JP2004121391A - Seam forming apparatus of sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seam forming apparatus having lock stitch and over-edge chain stitch, incorporating a knife cutting mechanism part in an existing structural space of a sewing machine, switching among lock stitch cutting cloth edge, over-edge chain stitch, and lock stitch not cutting the cloth edge, and accomplishing simple threading. <P>SOLUTION: This seam forming apparatus includes: a lock stitch/over-edge chain stitch switching control part 510 for controlling switching between the lock stitch and the over-edge chain stitch, interlocking with the seam selection of a seam select device 130 switching a sewing mode between the lock stitch wherein a needle thread and a bobbin thread are crossed to form a seam parallel to the surface of a body to be sewn and a seam vertical thereto and the over-edge chain stitch formed by an upper looper thread and a lower looper thread; a hatch opening and closing part 602 provided on a thread plate 8 to open an upper looper 30 in vertically elevating the thread plate, interlocking with the switching control to the over-edge chain stitch of the lock stitch/over-edge chain stitch switching control part; and a looper threading device 300 threading the upper looper and lower looper threads through the upper and lower loopers 40, respectively, in cooperation with switching control to the lock stitch of the part. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a stitch forming apparatus for a sewing machine, and more particularly to a sewing machine having both functions of a lock stitch and an overlock stitch, and in any of the stitches, a cloth edge can be cut with a scalpel, and the stitch is formed at once by a single sewing machine. The present invention relates to a stitch forming apparatus for a sewing machine.
[0002]
[Prior art]
Conventionally, there is a lockstitch which is the most basic stitch formed by a sewing machine as a stitch for sewing a plurality of cloths or the like. The lockstitch is formed by crossing the upper thread and the lower thread by scooping the upper thread passed through the needle through the cloth by the up and down movement of the needle and scooping it with the point of the hook that stores the lower thread. Multiple fabrics can be seamed along the seams.
[0003]
On the other hand, there is an overlock stitch to prevent fraying of an edge of a cloth or the like which is easily frayed. Edge overlock stitching is performed according to the number of threads for forming the stitch and the number of needles that move substantially perpendicularly to the cloth surface. One-needle two-thread overlock stitching (ISO4915 Stitch type 503) or one-needle three Thread edge overlock stitching (ISO4915 Stitch type 504) and two-needle five-thread sewing (so-called interlock combining stitching and edge overlocking) (ISO4915 Stitch)
type 516).
[0004]
However, in such edge overlock sewing, for example, a needle thread is scooped from the side with two hook-shaped needles called a looper, and a looper thread moving horizontally is scooped by a needle to form a seam. On the other hand, since the looper thread does not cross in the direction perpendicular to the surface of the cloth, the cloth cannot be joined together as in the case of lock sewing. That is, a so-called "laughing" phenomenon occurs in which the sewing thread is exposed when the two cloths joined by the overlock sewing are opened. Therefore, when performing overcasting by combining a plurality of cloths, it is necessary to form a stitch (ISO4915 Stitch type 517) for performing main sewing together.
[0005]
[Problems to be solved by the invention]
In such a stitch (Stitch type 517), it is preferable that the lock stitch portion and the overlock portion are as close as possible. However, the lock stitch requires a shuttle portion for storing a lower thread below a needle that moves up and down, On the other hand, the overlock sewing requires a looper, which is provided separately from the lockstitch and moves so as to cross the trajectory of the vertical movement of the needle, and therefore, both positions naturally have limitations.
[0006]
Therefore, sewing machines for both lockstitching and overlock stitching have been proposed (for example, see Patent Literature 1, Patent Literature 2, and Patent Literature 3), each of which is a sewing machine that selects and uses one function. It was impossible for the sewing machine to simultaneously perform the lockstitch and the overlock stitch in a state of being close to each other.
[0007]
On the other hand, there has been proposed an attempt to perform the lock stitch and the overlock stitch all at once (for example, refer to Patent Document 4, Patent Document 5, Patent Document 6, Patent Document 7). However, in these proposals, the overlock stitch is a looper that crosses the trajectory of the vertical movement of the needle provided separately from the lockstitch, but the movement applies the looper motion in the conventional overlock stitch as described above. Therefore, the lockstitch requires a shuttle section for storing the bobbin below the needle that moves up and down, and the overlock sewing is a looper that moves so as to cross the locus of the needle's up and down movement that is provided separately from the lockstitch. Therefore, it is difficult for the sewing machine to perform the lockstitch and the overlock stitch all at once in a state where the lockstitch and the overlock stitch are close to each other.
[0008]
Further, a lock stitch overlock attachment (trade name “Ruby Lock” manufactured by Toyo Seiki Kogyo Co., Ltd.) that performs lock stitch and overlock stitch at once has been proposed (see Patent Document 8). As shown in FIG. 28, this attachment is used by being fixed to a cloth presser bar 1001. A crank 1003 pivotally supported by an attachment frame 1002 by a needle bar (not shown) carrying a needle 1011 is used. The drive arm 1003a is driven, and the driven arm 1003b swings the upper looper drive plate 1005 pivotally supported by the attachment frame 1002 via the drive connection link 1004. The swing of the upper looper drive plate 1005 causes the upper looper 1007 pivotally supported by the attachment frame 1002 to swing through the upper looper drive link 1006. On the other hand, the pin 1005a protruding from the upper looper driving plate 1005 by the swing of the upper looper driving plate 1005 slides in the groove 1008a provided in the lower looper driving plate 1008 pivotally supported by the attachment frame 1002. The lower looper driving plate 1008 is swung. The swing of the lower looper drive plate 1008 swings the lower looper 1010 pivotally supported by the attachment frame 1002 via the lower looper drive link 1009. In this attachment structure, since the upper looper 1007 must cross the needle 1011 on the upper surface of the cloth (not shown), the upper looper 1007 is inclined upward to the left as viewed in the cloth feeding direction, and the lower looper 1010 is Must intersect with the needle 1011 on the lower surface of the cloth, so that it is inclined downward and to the left when viewed in the cloth feed direction, and furthermore, the upper and lower loopers 1007 and 1010 are mutually inclined such that the upper and lower loopers 1007 and 1010 intersect on the side of the cloth end. are doing.
[0009]
In the figure, reference numeral 1014 denotes a needle drop portion of the needle 1011; 1012, a thread tensioner; and 1013, a looper balance driven by a lower looper driving plate 1008.
[0010]
In the attachment having such a configuration, when the needle bar moves up and down, the needle thread (not shown) pierced by the needle 1011 and the bobbin thread (not shown) stored in the shuttle (not shown) form the book. While the sewing is formed, the drive arm 1003a of the crank 1003 is driven by the needle bar, and the driven arm 1003b swings the upper looper drive plate 1005 via the drive connection link 1004, and the swing of the upper looper drive plate 1005 Swings the upper looper 1007 via the upper looper drive link 1006, and the pin 1005 a projecting from the upper looper drive plate 1005 by the swing of the upper looper drive plate 1005 causes the groove provided on the lower looper drive plate 1008 to be formed. 1008a, the lower looper drive plate 1008 is swung, and the lower looper drive link 10 Since swinging the lower looper 1010 via 9, overedge sewing by looper thread after having pierced the respective upper looper 1007 and the lower looper 1010 and the lower looper thread (not shown) is formed.
[0011]
However, in such an attachment, since the upper and lower loopers 1007 and 1010 are inclined, a high processing technique in manufacturing is required, and a technique for maintaining accuracy in assembly is required. However, since this type of lockstitch sewing machine is used by ordinary users or by tailors, it is extremely troublesome to replace such an attachment with a work clamp and fix it to the work clamp bar. In addition, the operation of adjusting the positional relationship between the upper looper 1007 and the lower looper 1010 with respect to the needle after fixing is very complicated, and furthermore, after cutting the edge for sewing the cloth by using scissors in advance, the edge overlock sewing is performed. It has the major drawback of having to perform work.
[0012]
The inventor of the present application has proposed a one-needle, four-thread, lockstitch, overlock stitch structure which has both functions of lockstitch and overlock stitch, and can be formed at a time by a sewing machine, and a method of forming the same. (See Patent Document 9). For the user of the lockstitch sewing machine, there has been a strong demand for research and development of a lockstitch overlock sewing machine capable of realizing the single-needle, 4-thread lockstitch overlock stitch structure and a method for forming the same.
[0013]
In response to such a demand, the present inventor has proposed a looper drive mechanism for a sewing machine (see Patent Document 10).
[0014]
The looper drive mechanism of this sewing machine forms a lockstitch portion consisting of a stitch parallel to the surface of the sewing object and a vertical stitch by using the upper thread pierced through the needle and the lower thread stored in the shuttle. At the same time, the upper looper thread and the lower looper thread pierced respectively into the upper looper and the lower looper, and the looper drive mechanism that forms the overhanging part, the sword tip of each looper is viewed in the sewing direction, and the front side of the needle is A looper drive unit is disposed to face in the same direction so as to pass therethrough, and drives the upper looper and the lower looper so that their movement trajectories move on planes substantially parallel to each other. .
[0015]
In such a looper driving mechanism, the upper looper and the lower looper each pass the same point in front of the needle, the upper looper intersects the needle above the needle plate, and the lower looper crosses the needle below the needle plate. The upper looper descends in an arc-shaped trajectory behind the lower looper that retreats after crossing the needle, and the upper looper passes through the lowest point and rises before the lower looper reaches the final retreat point. , The lower looper blade tip passes through the lower looper locus before crossing with the upper looper locus.
[0016]
However, such a looper driving mechanism is configured such that the tip of the upper looper approaches the thread exit of the retreating lower looper and draws an arc-shaped locus, so that the shape of the upper looper and the lower looper is inevitable. And the thickness of the looper itself could not be increased. Also, when the upper looper rises, it passes immediately before the retreating lower looper blade point, so the shape of the upper looper and lower looper blade points is necessarily limited, and furthermore, there is a margin when these loopers cross. Since it disappears, a jump is likely to occur.
[0017]
In addition, since the looper drive mechanism has to incline the movement surface drawn by the upper looper and the lower looper with respect to the vertical movement direction of the needle, the looper drive unit itself is installed on the machine frame of the sewing machine so as to be inclined. The mounting seat must be inclined, which makes processing difficult and makes it difficult to achieve high processing accuracy. Therefore, it is difficult to adjust the position when assembling the upper looper and the lower looper that moves on the inclined motion surface.
[0018]
Further, since this looper drive mechanism has a structure in which the looper drive shaft is installed above the lower shaft, the space for assembling is limited, and assembly is difficult.
[0019]
Furthermore, since the upper looper that moves up and down by the looper drive mechanism during the overlock stitching, the upper looper vertical lifting hole that opens on the top of the bed must be closed with the lid cover at the time of lockstitching. At this time, the cover must be removed and opened, and it must be attached and closed. At the time of opening, it is necessary to store and manage the lid cover, which is troublesome, and sometimes an accident of losing the lid cover may occur. Further, in the stitch switching operation from the main stitch to the overlock stitch, there is an inconvenience in that, after selecting a stitch, an operation of further switching to the overlock stitch is required.
[0020]
Also, a single-needle, two-thread overlock stitch (ISO4915 Stitch type 503), a single-needle, three-thread overlock stitch (ISO4915 Stitch type 504), and a two-needle, five needles to form an overlock stitch In thread sewing (ISO4915 Stitch type 516) and the like, a cloth edge is cut by an upper knife that moves up and down and a lower knife that cooperates with the knife to perform overlock sewing.
[0021]
Thus, as in the case of such overlock sewing, simple overhanging can be performed by performing zigzag sewing by cutting the cloth edge with a scalpel using zigzag sewing even in main sewing.
[0022]
For this reason, sewing machines in which a scalpel cutting function is added to lockstitches have been proposed (for example, see Patent Literature 11, Patent Literature 12, and Patent Literature 13).
[0023]
However, in addition to the reason that a lockstitch sewing machine generally needs to be manufactured in a small size, it is desirable that the lockstitch portion and the knife cutting mechanism are as close as possible. There is a limit in incorporating a knife cutting mechanism into the existing structural space of the lockstitch machine because of the necessity of a hook portion for storing the lockstitch. Conventionally, it has been difficult to commercialize and commercialize the lockstitch because of the mechanism of the lockstitch machine.
[0024]
Therefore, the inventor of the present application can incorporate a scalpel cutting mechanism portion into the existing structural space of the sewing machine, cut the cloth edge, perform the overlock sewing with the lock stitch, and perform the lock stitch without cutting the cloth edge. There has been proposed a knife drive mechanism of a sewing machine that can easily switch and perform the operation to be performed (for example, see Patent Documents 14 and 15).
[0025]
The scalpel drive mechanism of the sewing machine includes an upper scalpel that moves up and down via a motion conversion mechanism that is linked to the rotation axis of the sewing machine, a lower scalpel that cuts a cloth edge in cooperation with the upper scalpel, and an upper scalpel supported by the machine frame. A knife drive unit that guides the knife slidably, and the motion conversion mechanism is connected to the upper knife via a clutch that pivots the knife drive unit to the retracted position when the knife is not operated and shuts off power to the upper knife. Are linked.
[0026]
Such a knife drive mechanism of the sewing machine can be stored simply by turning the upper knife to the upper left as viewed from the operator.
[0027]
However, such a scalpel drive mechanism of the sewing machine has a scalpel drive unit having an upper scalpel, which is installed on the right side of the needle when viewed from the operator, so that the upper scalpel crosses the front side of the needle with the needle during storage. Will move to. That is, since the upper thread hangs down from the balance located above the arm and is inserted through the thread hole of the needle, when the upper knife is stored, the upper knife intersects with the upper thread, which hinders sewing, and The upper thread must be re-threaded each time the machine is installed or stored. In order to solve such difficulties, it is conceivable to rotate the upper knife to the upper right and store it.However, the width of the lower end of the sewing machine arm becomes large and the pocket below the arm becomes narrow, which hinders the sewing operation. Will come.
[0028]
In addition, since the threading operation of passing the looper thread through the upper looper and the lower looper is manual, it has been difficult with a sewing machine in which a work space is limited because a looper thread balance and the like are incorporated in the sewing machine bed. In particular, in the case of a sewing machine using a free-arm type cylindrical bed, the work space is further narrowed, so that the threading operation to the upper looper and the lower looper requires opening the cover provided on the free arm portion of the bed. Threading must be performed with tweezers in a narrow place between parts, which is a very troublesome operation.
[0029]
Then, the inventor of the present application has proposed a threading device for a sewing machine that can automatically pass a thread through an upper looper and a lower looper with one touch by using a pressurized gas (see Patent Document 16). .
[0030]
The threading device of this sewing machine has a hollow structure including a looper having a hollow structure from a looper thread inlet to a looper blade tip thread outlet, a thread introduction unit for inserting a thread guided to the looper, and a thread guide outlet abutting the thread inlet of the looper. A yarn guide, a moving device for integrally connecting the yarn introduction portion to the looper blade tip yarn outlet, and an air pump for feeding the yarn from the yarn introduction portion integrally connected by the moving device to the looper blade tip yarn outlet. I have.
[0031]
Such a threading device for a sewing machine allows a threader to be threaded through a looper of a sewing machine having a looper with a single touch, thereby simplifying the threading operation and preventing malfunction.
[0032]
However, such a threading device of a sewing machine cannot connect a looper to a hollow thread guide and perform threading unless a hand pulley is turned and a set button for threading is pressed at a predetermined position. Further, after the completion of the threading, an operation to release the connected thread guide has to be performed. Furthermore, since it was not possible to connect the hollow fiber guide to the looper only from the direction of movement of the looper, it was difficult to apply the present invention to a high-speed rotary sewing machine.
[0033]
Further, since the upper looper thread and the lower looper thread are supplied directly from the thread guide to the upper looper and the lower looper, it is not possible to appropriately control the thread tightening timing and the thread supply amount. For this reason, it is difficult to balance the thread tension between the upper thread and the lower thread of the lockstitch portion and the upper looper thread and the lower looper thread of the overlock stitch portion, and if the looseness of the upper looper thread and the lower looper thread during sewing is reduced, the curl (edge (The state in which the cloth is folded due to the tightening of the overlock thread) is generated, and if the tightening of the upper looper thread and the lower looper thread is loosened, the cloth edge floats and the thread tension operation for producing a preferable sewing finish becomes difficult. Further, since the upper looper thread and the lower looper thread may pull the upper thread and the lower thread of the main sewing portion, it is difficult to form a beautiful stitch.
[0034]
The present invention has been made in order to solve such a conventional problem, and has both functions of a lockstitch and an overlock stitch, and can be formed at once by one sewing machine. A knife cutting mechanism can be incorporated into the existing structural space, and it can be executed by switching between the work of cutting the cloth edge and performing the overlock sewing with the lockstitch and the work of performing the lockstitch without cutting the cloth edge, Further, the present invention relates to a stitch forming apparatus for a sewing machine which can easily perform threading.
[0035]
[Patent Document 1] Japanese Patent Publication No. 56-15268
[Patent Document 2] Japanese Patent Publication No. 60-25145
[Patent Document 3] Japanese Patent Publication No. 61-25396
[Patent Document 4] JP-A-55-113490
[Patent Document 5] JP-A-55-136085
[Patent Document 6] JP-A-55-146190
[Patent Document 7] JP-A-63-122495
[Patent Document 8] Japanese Patent No. 2541601
[Patent Document 9] Japanese Patent No. 2672097
[Patent Document 10] JP-A-2002-102574
[Patent Document 11] Japanese Utility Model Laid-Open No. 57-90056
[Patent Document 12] Japanese Utility Model Laid-Open No. 57-90057
[Patent Document 13] Japanese Patent Publication No. 58-31950
[Patent Document 14] JP-A-2002-018170
[Patent Document 15] JP-A-2002-126386
[Patent Document 16] Japanese Patent No. 2865470
[Means for Solving the Problems]
A stitch forming apparatus for a sewing machine according to the present invention, which achieves the above object, has a needle plate formed by an upper thread penetrated by a needle that moves up and down in a direction perpendicular to a needle plate and a lower thread stored in a shuttle. When the upper thread penetrating the needle which reciprocates vertically in the vertical direction through the sewn object at every feed of the sewn object placed on the needle is lifted from the bottom dead center of the needle, Straight stitch, zigzag, consisting of stitches parallel to the surface of the sewn body and stitches perpendicular to the surface of the body to be sewn by storing the lower thread and scooping it with the point of a rotating rotary hook and crossing the upper thread and the lower thread Form a main sewing part such as sewing, make a reciprocating motion that draws a locus above and below the needle plate, an upper looper that intersects the locus of the needle above the needle plate, draw a locus below the needle plate, draw the locus of the needle and An overlock sewing portion is formed by the upper looper thread and the lower looper thread pierced through the lower looper that intersects with the locus of the looper, respectively. Together, it is for the cloth feed control of the present sewing or needle of the needle drop control in accordance with the stitch selection stitch selection device switches the overedge sewing sewing mode and the fabric workpiece.
[0036]
The stitch forming device of the sewing machine includes a lockstitch / overlock switchover control unit that controls switching between lockstitch and overlock stitch in conjunction with stitch selection by a stitch selection device, and a lockstitch / edge overlock provided on the needle plate. A hatch that opens when the upper looper moves up and down the needle plate in conjunction with the overlock stitching switchover control of the overlock switchover control unit, and interlocks with the switchover to lockstitching of the lockstitch and edge overlocking switchover control unit And a looper threading device for threading the upper looper thread and the lower looper thread through the upper looper and the lower looper, respectively.
[0037]
According to such a stitch forming device for a household sewing machine, when the stitch selection of the stitch selecting device is other than the overlock stitching, the lock stitching / overlock stitching switching control unit automatically performs switching control other than the overlock stitching. Therefore, the looper threading device can thread the upper looper thread and the lower looper thread through the upper looper and the lower looper, respectively, in conjunction with the switching control. Further, when the stitch selection of the stitch selection device is the overlock stitching, the lock stitch / overlock stitching switching control unit automatically switches to the overlock stitching. The upper looper can be opened when the upper looper is moved up and down the needle plate in conjunction with the switching control to the overlock sewing by the overlock switching control section.
[0038]
Further, the stitch forming apparatus of the household sewing machine is provided with a needle drop control unit that controls the needle drop of the needle in conjunction with the switching control of the lockstitch / overlock switching control unit. With this, when the lockstitch / overlock switchover control unit is controlled to switch to the lockstitch, the needle drop control unit interlocks with the switching control to the lockstitch by the lockstitch / edge overlock switchover control unit, and the position of the needle is changed. Needle drop control is automatically performed to move to the lock stitch needle drop position.When the lock stitch / overlock switchover control unit is switched to overlock stitch, the needle drop control unit controls the lock stitch / overlock switch. The needle drop control can be performed so that the position of the needle automatically moves to the edge overlock needle drop position in conjunction with the switching control to the overlock sewing by the section.
[0039]
Further, the stitch forming apparatus of the household sewing machine is provided with a cloth feeder that controls the cloth feed of the sewing object in conjunction with the stitch selection of the stitch selection device. Thereby, the cloth feed control of the sewn object according to the stitch selected by the stitch selecting device can be performed.
[0040]
Further, in the stitch forming device of a household sewing machine, the upper looper is opened when the upper looper moves up and down the needle plate in conjunction with the switching control to the overlock stitching of the lockstitch / overlock stitching switching control unit. A hatch opening / closing section is provided which drives the opening / closing of the hatch so that the upper looper is closed when the upper looper is retracted to a fixed position in conjunction with the overlocking switching control section switching control to lockstitch. With this, when the lockstitch / overlock switchover control unit is controlled to switch to the lockstitch, the hatch opening / closing unit can automatically close the hatch when the upper looper is retracted to a fixed position below the needle plate. This eliminates the need to open and close the lid that closes the opening formed in the needle plate in order to raise and lower the upper looper above and below the needle plate, and saves time for storing and managing the lid after removing the lid. Can be omitted, and the accident of losing the lid can be prevented. Further, the hatch opening / closing section is opened when the upper looper moves up and down the needle plate in conjunction with the switching control to the overlock stitching of the lockstitch / overlocking switching control section. When the upper looper is retracted to the home position in conjunction with the switching control to the lockstitch of the section, the looper clutch is completely disengaged, the power to the upper looper is shut off, and the hatch opening / closing spring for closing the hatch is closed. It is provided so as to interlock with the sewing / overlock switching control unit. Thus, the hatch can be automatically opened and closed by the elastic force of the hatch opening and closing spring provided in the hatch opening and closing unit.
[0041]
Further, in a stitch forming apparatus for a household sewing machine, a hatch is used to sew cloth dust cut off at the time of overlock sewing of an upper looper thread pierced through an upper looper that rises and falls in an opening formed when the hatch is opened. When the hatch is closed, a cloth waste guide plate that forms the same plane as the needle plate is hinged together with the hatch when the hatch is closed. Thus, it is possible to prevent the cloth waste from falling into the opening of the needle plate and adversely affecting the upper looper, the lower looper, and the like.
[0042]
Further, in the stitch forming apparatus of a household sewing machine, power is transmitted to the upper looper and the lower looper in conjunction with the switching control to the overlock stitching of the lockstitch / overlock stitching switching control section, and the lockstitch portion and the overlock stitch portion are transmitted. And a looper clutch that cuts off the power when the upper looper is evacuated to a fixed position in conjunction with the switching control to the lockstitch by the lockstitch / overlock switchover control unit, thereby forming a lockstitch portion. . This facilitates switching control between the lockstitch and the overlock stitch.
[0043]
Further, in the stitch forming apparatus of a household sewing machine, power is transmitted to the upper looper and the lower looper in conjunction with the switching control to the overlock stitching of the lockstitch / overlock stitching switching control section, and the lockstitch portion and the overlock stitch portion are transmitted. A looper clutch that forms a lockstitch by shutting off the power when the upper looper is retracted to a fixed position in conjunction with the switching control to the lockstitch by the lockstitch / overlock switching control section. A crank attached to a looper drive shaft driven when the motor enters, an L-shaped looper drive link connected to the crank, a long link end of the L-shaped looper drive link supported at the intermediate portion by the machine frame and having one end. The upper looper mounting arm, which is connected to the upper looper and carries the upper looper and swings with the rotation of the crank, is connected to the short link end of the L-shaped looper drive link and performs an elliptical motion at a constant speed with the rotation of the crank. Lower looper drive Link, one end is supported by a machine frame at an intermediate portion and a looper drive portion composed of the lower looper mounting arm for carrying the lower looper is connected to the lower looper drive link. Accordingly, when the looper clutch is engaged, that is, when the lock stitch / overlock switching control section is switched to the overlock stitch and the crank of the looper drive section rotates, the L-shaped looper drive connected to this crank is rotated. Since the link is driven, the upper looper mounting arm connected to the long link end of the L-shaped looper drive link converts the rotational motion of the looper drive shaft into the swinging motion of the upper looper, while the L-shaped looper drive link Since the short link end is restricted by the four-bar rotating chain formed by the crank attached to the looper drive shaft, the upper looper mounting arm, and the long link of the L-shaped looper drive link, the short link end generates a non-uniform velocity elliptic motion. A lower looper mounting arm connected via a lower looper drive link converts the rotational motion of the looper drive shaft into a non-uniform swing motion of the lower looper. Therefore, when the looper drive section is driven and the tip of the upper looper and the tip of the lower looper cross each other, collision can be prevented.
[0044]
Further, in the stitch forming apparatus of a household sewing machine, the upper looper thread and the lower looper thread are interlocked with the movement trajectories of the upper looper and the lower looper in accordance with the switching control to the overlock stitching of the lockstitch / overlock stitching switching control section. The upper looper thread and lower looper thread necessary for edge overlock when the machine is looped on the needle is threaded through the thread tensioner and stored, and the needle comes off from the upper looper thread and lower looper thread. After the upper thread is tightened by the upper thread balance, a looper thread supply means is provided to supply the upper looper thread and the lower looper thread which have been wound and stored to the upper looper and the lower looper. Accordingly, in the overlock sewing, when the needle is pierced through the sewn body, the movement of the upper looper and the lower looper located between the thread tensioner and the overlock seam in advance and the thread of the looper thread supply means. The upper looper yarn and the lower looper yarn accumulated by pulling can be released and tightened.
[0045]
In a stitch forming apparatus for a household sewing machine, the upper looper and the lower looper have a hollow structure from the entrance of the looper thread to the exit of the looper blade tip thread, and the upper looper thread and the lower looper thread guided to the upper looper and the lower looper are inserted. The upper looper and lower looper loop entrance when the upper looper is retracted to the fixed position below the needle plate in conjunction with the switching control to the lockstitch from the thread introduction port to the lockstitch / overlock switchover control section. A looper threading device having a hollow thread guide for threading the upper looper thread and the lower looper thread to the thread guide outlet that matches the thread guide outlet, and the upper looper thread and the lower looper with the looper thread inlets aligned with the thread guide outlet. There is provided a threading air pump for sending a looper thread and a lower looper thread from a thread guide inlet through a thread guide outlet of the thread guide, an upper looper, a looper thread inlet of the lower looper, and a looper tip end thread outlet. As a result, when the lockstitch / overlock switchover control unit is controlled to switch to the lockstitch and the upper looper is retracted to a fixed position below the needle plate, the looper threading device is turned into the hollows for the upper looper and the lower looper. Since the upper looper and the lower looper's looper thread inlets are respectively matched with the thread guide outlet of the thread guide, the thread guide air pump passes the thread guide outlet, upper looper, The upper looper thread and the lower looper thread can be sent out toward the lower looper looper thread entrance and the looper blade tip thread exit. Further, in a stitch forming apparatus of a household sewing machine provided with such a looper threading device and a threading air pump, an upper looper, Power is transmitted to the lower looper to form an overlock stitch, and the power is cut off in conjunction with the switching control to the lockstitch by the lockstitch and overlock stitching switching control unit to form the lock stitch, and the upper A looper clutch is provided for retracting the looper to a fixed position and matching the yarn guide outlet with the looper yarn inlet. This facilitates switching control between the lockstitch and the overlock stitch.
[0046]
Further, in a stitch forming apparatus of a household sewing machine provided with a looper threading device and a threading air pump, the upper looper, the lower looper's looper thread entrance and the thread guide outlet of the thread guide are moving surfaces drawn by the upper looper and the lower looper. Are arranged in the direction crossing each other. Further, the power is transmitted to the upper looper and the lower looper in conjunction with the switching control to the overlock stitching of the lockstitching / overlocking switchover control unit to form an overlocking stitching portion, and the bookbinding of the lockstitching / overlocking overturning control unit is performed. A looper clutch is provided to form a lockstitch portion by shutting off the power in conjunction with the switching control to the sewing, to retract the upper looper to a fixed position when the power is shut off, and to match the thread guide outlet with the looper thread entrance. This facilitates processing, assembling, and adjustment for matching the looper thread entrance of the upper looper and the lower looper with the thread guide exit of the thread guide, and also facilitates the switching control between the lockstitch and the overlock stitch.
[0047]
Further, in the stitch forming apparatus of a household sewing machine, when the upper looper descends and the looper thread inlet passes through the thread guide outlet, the upper looper thread is entangled with the needle, and the upper looper thread starts tightening, and the upper looper is moved. After the thread is further lowered and the upper looper thread is tightened, the upper looper reaches the bottom dead center and the needle is pulled out of the sewing body. When the ascent starts, the accumulated upper looper thread is released, and when the upper looper rises and passes through the upper looper top dead center and starts descending, the needle moves upward while scooping the upper looper thread from top dead center. When the lower looper retracts and the looper thread inlet passes through the thread guide outlet, the lower looper thread entangles with the needle and starts tightening of the lower looper thread. The lower looper is further retracted and the lower looper thread is tightened. And a lower looper thread balance that rewinds and stores the lower looper thread through the thread tensioner until the lower looper reaches the final retreat point, and releases the stored thread when the lower looper advances. I have. Thereby, in the overlock sewing, when the needle is pierced through the sewn body, the movement of the upper looper and the lower looper located between the thread tensioner and the overlock seam in advance and the upper looper thread balance, The upper looper thread and the lower looper thread accumulated by the threading of the looper thread balance can be released and tightened. Further, the upper looper thread balance has a looper balance drive arm pivotally attached to the machine frame and having a speed change drive cam groove, and a cam drive that slides in the speed change drive cam groove to shift the looper balance drive arm by the looper drive unit. The lower looper thread balance is provided at one end of the looper balance driving arm. Thus, the drive control of the upper looper thread balance and the lower looper thread balance can be performed only by the cam driver that is driven by the looper drive unit.
[0048]
Further, in a stitch forming apparatus for a household sewing machine, an upper knife that moves up and down through a motion conversion mechanism that is linked to a rotation shaft that drives a needle is slidably guided to cooperate with the upper knife. A scalpel drive section for cutting the cloth edge of the sewing body with a scalpel is provided with a 4-bar rotary link having a different internode length. The movement conversion mechanism transmits the vertical movement to the upper knife in the operating position, and moves up and down to the upper knife in the retracted position. It is connected to the upper knife via a female clutch that blocks the movement.
[0049]
According to such a stitch forming apparatus for a household sewing machine, the knife cutting mechanism can be compactly incorporated in the existing structural space of the sewing machine. The work and the work of performing the main sewing without cutting the cloth edge can be easily switched and executed.
[0050]
In addition, the stitch forming device of the sewing machine of the present invention that achieves the above object is characterized in that an upper thread penetrated by a needle that moves up and down in a vertical direction with respect to a needle plate and a lower thread stored in a shuttle. When the needle thread penetrating the needle which reciprocates vertically in the vertical direction through the sewn object at every feed of the sewn object placed on the needle plate is raised from the bottom dead center of the needle, A lock stitch portion comprising a stitch parallel to the surface of the sewn body and a stitch in the vertical direction, where the lower thread is stored below and scooped with a sword tip of a rotating rotary hook to cross the upper thread and the lower thread. The upper looper crosses the trajectory of the needle above the needle plate, draws a trajectory below the needle plate, and the trajectory of the needle and the upper looper respectively. An overlock sewing portion is formed by the upper looper thread and the lower looper thread that have been passed through the intersecting lower loopers, respectively.
[0051]
The stitch forming apparatus of this sewing machine is provided with an upper looper thread and a lower looper necessary for overlock sewing when the upper looper thread and the lower looper thread are looped around the needle in conjunction with the movement locus of the upper looper and the lower looper. The yarn is fed through the thread tensioner and stored, and the needle is pulled out of the upper looper thread and the lower looper thread, and the upper thread is tightened by the upper thread balance. There is provided a looper thread supply means for supplying the looper thread and the lower looper thread to the upper looper and the lower looper.
[0052]
According to such a stitch forming apparatus of an industrial sewing machine, when the needle is pierced through the sewing object, the movement of the upper looper and the lower looper which are located between the thread tensioner and the overlock stitch in advance. The upper looper thread and the lower looper thread accumulated by the threading of the looper thread supplying means can be released and tightened.
[0053]
In addition, the stitch forming device of the industrial sewing machine has an upper looper and a lower looper having a hollow structure from a looper thread inlet to a looper blade tip thread outlet, and inserts an upper looper thread and a lower looper thread guided to the upper looper and the lower looper. A looper threading device having a hollow thread guide for threading the upper looper thread and the lower looper thread from the thread introduction port to the thread guide outlets corresponding to the looper thread inlets of the upper looper and the lower looper is provided. The looper thread entrance of the looper and the thread guide exit of the thread guide are arranged in a direction intersecting the movement plane drawn by the upper looper and the lower looper. A threading air pump for feeding a looper thread and a lower looper thread from a thread guide inlet through a thread guide outlet of the thread guide, an upper looper, a looper thread inlet of the lower looper, and a looper tip end thread outlet is provided.
[0054]
According to such a stitch forming apparatus for an industrial sewing machine, the industrial lock stitch overlock sewing machine is a mechanism that always performs edge overlock stitching, so that it becomes the swing center of the upper looper mounting arm of the looper drive unit. The upper looper mounting arm shaft and the lower looper mounting arm shaft, which is the swing center of the lower looper mounting arm, have a hollow structure and are used as the looper thread inlets of the upper looper and the lower looper. Since the upper looper and the lower looper's looper thread inlet can always be respectively aligned with the thread guide outlets of the respective hollow thread guides for the lower looper, the hollow thread guides of the respective hollow thread guides are threaded by the threading air pump in this matched state. The upper looper thread and lower looper thread can be sent from the inlet to the thread guide outlet, upper looper, lower looper loop inlet, and looper blade point thread outlet. Processing for matching the thread guide outlet of Pas yarn inlet and the yarn guide, assembling, adjustment is facilitated.
[0055]
Further, in the stitch forming apparatus of the industrial sewing machine, when the upper looper descends and the looper thread inlet passes through the thread guide outlet, the upper looper thread is entangled with the needle, and the upper looper thread starts to be tightened, and the upper looper is moved. After the thread is further lowered and the upper looper thread is tightened, the upper looper reaches the bottom dead center and the needle is pulled out of the sewing body. When the ascent starts, the accumulated upper looper thread is released, and when the upper looper rises and passes through the upper looper top dead center and starts descending, the needle moves upward while scooping the upper looper thread from top dead center. When the lower looper retracts and the looper thread inlet passes through the thread guide outlet, the lower looper thread entangles with the needle and starts tightening of the lower looper thread. The lower looper is further retracted and the lower looper thread is tightened. And a lower looper thread balance that rewinds and stores the lower looper thread through the thread tensioner until the lower looper reaches the final retreat point, and releases the stored thread when the lower looper advances. I have. Accordingly, when the needle is pierced through the sewing object, the movement of the upper looper and the lower looper and the thread of the upper looper thread balance and the lower looper thread balance which are located between the thread tensioner and the overlock stitch in advance. The upper looper thread and the lower looper thread accumulated by pulling can be released and tightened. Further, the upper looper thread balance is provided with a looper balance driving arm pivotally attached to the machine frame and having a speed change drive cam groove, and a cam that slides in the speed change drive cam groove to drive the looper balance drive arm by the looper drive unit. The lower looper thread balance is provided at one end of the looper balance driving arm. Thus, the drive control of the upper looper thread balance and the lower looper thread balance can be performed only by the cam driver that is driven by the looper drive unit.
[0056]
Also, in the stitch forming apparatus of the industrial sewing machine, power is transmitted to the upper looper and the lower looper to form an overlock stitch portion, and when the upper looper is retracted to a fixed position, the power is shut off to lock the main stitch portion. A looper clutch to be formed, a crank mounted on a looper drive shaft that is driven when the looper clutch is engaged and performing a rotary motion, an L-shaped looper drive link connected to the crank, and one end supported by the machine frame at an intermediate portion and having one end L The upper looper mounting arm, which is connected to the long link end of the L-shaped looper drive link and carries the upper looper and swings with the rotation of the crank, is connected to the short link end of the L-shaped looper drive link for rotation of the crank. A lower looper drive link that makes an unequal-velocity elliptical motion, and a lower looper drive arm that includes a lower looper mounting arm that is supported by the machine frame at an intermediate portion and has one end connected to the lower looper drive link to carry the lower looper. And a part.
[0057]
According to such a stitch forming apparatus for an industrial sewing machine, when the crank of the looper drive section rotates, the L-shaped looper drive link connected to the crank is driven. The upper looper mounting arm connected to the long link end converts the rotational motion of the looper drive shaft into the swinging motion of the upper looper, while the short link end of the L-shaped looper drive link connects the crank attached to the looper drive shaft. The lower looper is connected via the lower looper drive link because the upper looper mounting arm and the L-shaped looper drive link are constrained by the four-bar rotating chain formed by the long link to generate unequal velocity elliptical motion. The mounting arm converts the rotational motion of the looper drive shaft into a non-uniform rocking motion of the lower looper. Therefore, when the looper drive section is driven and the tip of the upper looper and the tip of the lower looper cross each other, collision can be prevented.
[0058]
In addition, the stitch forming device of the sewing machine of the present invention that achieves the above object is characterized in that an upper thread penetrated by a needle that moves up and down in a vertical direction with respect to a needle plate and a lower thread stored in a shuttle. When the needle thread penetrating the needle which reciprocates vertically in the vertical direction through the sewn object at every feed of the sewn object placed on the needle plate is raised from the bottom dead center of the needle, A straight stitch comprising a seam parallel to the surface of the body to be sewn and a vertical seam crossing the upper thread and the lower thread by scooping with a sword point of a rotating kettle which stores a lower thread and rotates below. , Regular sewing such as zigzag sewing and the like.
[0059]
The stitch forming device of this sewing machine is covered by an upper knife that moves up and down via a motion conversion mechanism that is linked to a rotating shaft that drives a needle, and a lower knife that slides and guides the upper knife to cooperate with the upper knife. The knife drive section for cutting the cloth edge of the sewing body is irregularly moved between the operating position on the needle plate when the knife is operated and the retracted position at the lower part of the arm of the sewing machine when the knife is not operated by the four-bar rotating links having different internode lengths. The movement conversion mechanism is pivotally attached to the machine frame so as to move in an elliptical trajectory, and the motion conversion mechanism transmits the vertical movement to the upper knife at the operating position and blocks the vertical movement to the upper knife at the retracted position The upper knife is connected to the upper knife via a female clutch.
[0060]
According to such a stitch forming apparatus for a home lockstitch sewing machine, a female cutting mechanism can be compactly incorporated in the existing structural space of the sewing machine. And the work of performing the main sewing without cutting the fabric edge can be easily switched and executed.
[0061]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment in which the stitch forming apparatus of the present invention is applied to a lock stitch overlock sewing machine will be described with reference to the drawings.
[0062]
As shown in FIG. 1, the lock stitch overlock sewing machine includes a lock stitch forming mechanism 100 that forms a lock stitch portion composed of stitches parallel to and perpendicular to the surface of the sewn body, and a surface of the sewn body. And a looper drive mechanism 50 for forming an overhanging portion.
[0063]
The lockstitch forming mechanism 100 has a known (well-known) structure (JP-A-49-117148, JP-A-52-154448, JP-A-53-108547, and JP-A-54-60052). JP-A-54-110049, JP-A-55-35676, JP-A-55-113490, JP-A-55-146190, JP-A-56-3091 and the like. , And a detailed description thereof will be omitted. However, in brief, as shown in FIG. 2, the needle 10 is fixed to the needle bar 11 (FIG. 3) and moves up and down with a trajectory L10 in the direction perpendicular to the needle plate 8. The shuttle 20 is provided with a horizontal rotary motion that draws a trajectory L20 in the same cycle. The upper thread 1 pierced through the needle 10 and the lower thread 2 stored in the shuttle 20 are used to cover the needle placed on the needle plate 8. When the upper thread 1 pierced from the bottom dead center of the needle 10 when the upper thread 1 pierced the needle 10 reciprocating in the vertical direction through the sewn body at every feed of the sewn body, the upper thread 1 A book consisting of stitches parallel to and perpendicular to the surface of the body to be sewn by storing the lower thread 2 and scooping it with the sword tip 21 of the shuttle 20 that moves horizontally and intersecting the upper thread 1 and the lower thread 2 The sewing part 6 is formed.
[0064]
As shown in FIGS. 1 and 3, the needle bar 11 to which the needle 10 is fixed at the tip end is a movement in which the upper end is slidably supported in a vertical direction by a needle frame pivotally supported by the machine frame FR. The needle bar drive unit MT1 having a needle bar crank as a conversion mechanism moves up and down. In addition, the shuttle (sword point) 20 may be not only full rotation but also half rotation. In short, if the locus L20 and the locus L10 of the needle 10 intersect and the needle thread 21 scoops the needle thread 1, It is good (see FIG. 2).
[0065]
Further, in the lock stitch overlock sewing machine, the sewing operator performs a straight stitch, a zigzag stitch, and the like by rotating the stitch selection knob NB and switching the pattern stitch selection dial DL to each of the various rotation modes to switch the sewing mode. be able to. The lockstitch forming mechanism 100 corresponding to this sewing mode also has a well-known (well-known) structure (Japanese Patent Application Laid-Open Nos. 48-50853, 49-32754, 50-73754, and 50-73754). JP-A-54-4646, JP-A-54-6643, JP-A-54-120057, JP-A-55-16676, JP-A-55-216, and JP-A-55-4787. For example, when the needle 10 is moved up and down, the needle 10 is moved in a direction perpendicular to the cloth feeding direction for each needle, and the needle 10 is cooperated with the cloth feeding. A needle drop control unit 110 (see FIG. 3) for generating zigzag sewing and pattern sewing is provided. The needle drop control unit 110 includes a pattern stitch generation device 120, a stitch selection device 130, and a needle swing device 140. The pattern stitch generation device 120 and the stitch selection device 130 are unitized, and The eye generating device 120 is incorporated in the upper part of the stitch selecting device 130, and controls the needle dropping of the needle 10 in conjunction with the switching control of the lockstitch / overlock switching control unit 510 described later. Thus, when the lockstitch / overlock switching control section 510 is controlled to switch to the lockstitch, the needle drop control section 110 interlocks with the switching control to the lockstitch by the lockstitch / edge overlock switching control section 510, and the needle Needle drop control is performed so that the position 10 automatically moves to the lock stitch needle drop position. When the lock stitch / overlock switchover control unit 510 is controlled to switch to the overlock stitch, the needle drop control unit 110 starts Needle drop control can be performed so that the position of the needle 10 automatically moves to the overlock stitch needle drop position in conjunction with the switching control to the overlock sewing by the sewing / overlock switch control unit 510.
[0066]
The stitch selection device 130 is rotated by operating a stitch selection knob NB (see FIG. 1) to set a pattern stitch, and a stitch selection shaft 111 for displaying various stitches and a stitch selection shaft 111 by a gear mechanism. And a pattern stitch selection dial DL interlocked with the pattern stitcher. When the sewer operates a stitch selection knob NB to selectively switch stitches, a necessary cam is selected from various cams of the pattern stitch generator 120. The needle swing amount, the needle swing position, and the needle feed amount are determined. The feed amount of the feed dog FB described later is adjusted by a feed adjustment knob 131 (see FIG. 3).
[0067]
Since such a needle drop control unit 110 also has a well-known (well-known) structure, detailed description thereof will be omitted, but drive control of the lockstitch forming mechanism 100 by the pattern stitch generation device 120 and the stitch selection device 130 is performed. are doing.
[0068]
The lockstitch forming operation by the lockstitch forming mechanism 100 configured as described above will be described with reference to FIGS.
[0069]
The needle 10 moves up and down from a rotation shaft, that is, an upper shaft S1 supported by the machine frame FR of the lockstitch overlock sewing machine via a needle bar drive unit MT1. In addition, the upper shaft S1 drives the upper thread balance 16 for lifting and feeding out the upper thread 1 up and down by a motion conversion mechanism 71 (see FIG. 12) described later. The upper shaft S1 is driven to rotate by a hand pulley HP from a motor M via a timing belt TB. A needle frame (not shown) that supports the needle bar 11 to which the needle 10 is fixed so as to be slidable in the up-down direction is needle-by-needle driven by a pattern stitch generating device 120 by a needle vibration device 140. Shift the left and right position. The needle plate 8 is formed in a horizontally long shape so that the needle drop hole PS can cope with a change in the left and right position of the needle 10 (see FIG. 20).
[0070]
The shuttle 20 is rotated from a rotary shaft, that is, a lower shaft S2, which is supported by the machine frame FR of the lock-stitched overlock sewing machine, via a shuttle drive screw gear MT2 which is a motion conversion mechanism. The shuttle drive screw gear MT2 is for rotating the rotary motion from the lower shaft S2 in the feed direction by 90 degrees and transmitting it to the shuttle 20. The driven gear 202 is fixed to the shuttle 20, and the driving gear 201 is a lower shaft. It is fitted and fixed in S2. The lower shaft S2 is rotationally driven by the timing belt TB in synchronization with the upper shaft S1 and at a double speed (1: 2). The timing of the shuttle 20 is adjusted so that the loop of the upper thread 10 is scooped by the blade point 21 of the shuttle 20 when the needle 10 rises from the lowest point by rotating twice with respect to the vertical movement of one stitch.
[0071]
Further, the feed amount of the feed dog FB of the cloth feeder for cloth feed is also driven and controlled by the pattern stitch generating device 120. The cloth feed movement of the feed dog FB is driven by a feed dog drive unit 121 having a triangular cam from the lower shaft S2, and the feed dog drive unit 121 raises the feed dog FB to push up the sewing object. In this state, the feed dog FB is advanced to move the sewing object forward, and further, the feed dog FB is lowered to leave the sewing object on the needle plate 8 and the feed dog FB is retracted to the original position. This is one process of fabric feeding. Thereby, the cloth feed control of the sewn object according to the stitch selected by the stitch selection device 130 can be performed.
[0072]
As shown in FIGS. 1 and 2, the overlock sewing machine performs a reciprocating motion to draw a substantially circular locus L30 above and below the needle plate 8, and moves the needle 10 above the needle plate 8. The upper looper 30 intersecting with L10, draws a substantially arc-shaped locus L40 below the needle plate 8, and is pierced by the lower looper 40 intersecting with the locus L10 of the needle 10 and the locus L30 of the upper looper 30, respectively. Further, a looper drive mechanism 50 that forms the overhanging portion 7 by the upper looper thread 3 and the lower looper thread 4 is provided.
[0073]
The looper drive mechanism 50 includes an upper looper 30 and a lower looper 40 provided below the needle plate 8, respectively, so that the respective blade tips 31 and 41 are viewed in the sewing direction and pass in the same direction so as to pass through the front side surface of the needle 10. And drives the upper looper 30 and the lower looper 40 so that their trajectories L30 and L40 move in a plane substantially parallel to each other. The upper looper thread 3 penetrates the upper looper 30 that reciprocates in a circular path L30 that crosses the locus L10 of the upper part of the needle plate 8 and crosses the needle plate 8, and the upper looper 30 descends from the top dead center. The needle 10 descends from the top dead center, and is pierced by the lower looper 40 that reciprocates by drawing a locus L40 that intersects the locus L10 of the needle 10 and the locus L30 of the upper looper 30 below the needle plate 8. Lower looper thread 4 When the lower looper 40 moves from one end of the locus L40 to the other end, the lower looper 40 scoops with the descending needle 10 below the needle plate 8, and when the lower looper 40 moves to the other end, the lower looper thread 4 rises from the bottom dead center. When the upper looper 30 scoops, the upper looper thread 3 and the lower looper thread 4 intersect at the edge 5c of the sewing object 5 and the upper looper thread 3 passes through the upper surface 5a of the sewing object 5 and A looper drive section 60 (FIG. 4) is provided so that the lower looper thread 4 passes through the lower surface 5b of the sewing body 5 and crosses with the main sewing section 6 to form an overlock sewing section 7.
[0074]
The looper drive unit 60 is provided below the needle plate 8, and as shown in FIG. 4, the rotational motion from the lower shaft S2 is transmitted via a looper clutch 500 (FIGS. 8, 9, and 10) described later. A crank 61a attached to one end of a looper drive shaft 61 that is driven when the looper clutch 500 is engaged, and performs a rotary motion; an L-shaped looper drive link 62 connected to the crank 61a; An upper looper mounting arm 63 pivotally supported by 67 and having one end connected to the long link end 62a of the L-shaped looper drive link 62 for carrying the upper looper 30 and swinging with the rotation of the crank 62; A lower looper drive link 64, which is connected to the short link end 62b of the drive link 62 and moves unequally elliptically with the rotational movement of the crank 61a; And a lower looper mounting arm 65 that carries the lower looper 40 and is connected to the looper drive link 64. These cranks 61a and the like are incorporated in a looper base 67 mounted on the machine frame FR by a looper base mounting plate 620. Have been.
[0075]
More specifically, the looper drive shaft 61 is rotatably attached to the looper base 67, and the crank 61a is rotatably connected to the long link and short link connecting portion 62c of the L-shaped looper drive link 62. . The upper looper mounting arm 63 having one end connected to the long link end 62a of the L-shaped looper drive link 62 has an intermediate portion rotatably connected to the looper base 67, and the other end provided by an upper looper mounting plate 68. The upper looper 30 is fixed. An upper looper thread pipe 301 for passing the upper looper thread 3 is attached to the upper looper 30. A lower looper drive link 64 having one end connected to the short link end 62b of the L-shaped looper drive link 62 has the other end pivotally attached to one end of a lower looper drive arm 66. One end is fixed to a lower looper mounting arm 65 that is pivotally mounted at one end to a looper base 67 with a lower looper mounting arm shaft 69. The lower looper 40 is fixed to the other end of the lower looper mounting arm 65. A lower looper thread pipe 401 for passing the lower looper thread 4 is attached to the lower looper 40.
[0076]
The overlocking operation performed by the looper driving unit 60 will be described with reference to FIGS. 3, 4, 5, and 6. FIG.
[0077]
When the lower shaft S2 rotates, the looper drive shaft 61 rotates via the looper clutch 500, and the L-shaped looper drive link 62 connected to the crank 61a of the looper drive shaft 61 converts the rotation to another motion. I do. That is, the short link end 62b of the L-shaped looper drive link 62 is a four-bar rotary chain formed by the crank 61a mounted on the looper drive shaft 61, the upper looper mounting arm 63, and the long link of the L-shaped looper drive link 62. (See FIG. 7), the lower looper drive arm 66 connected via the lower looper drive link 64 controls the rotational movement of the looper drive shaft 61 to lower looper mounting arm 65. Is converted into an unequal-speed oscillating motion of the lower looper 40 carried by the lower looper 40, so that the lower looper 40 oscillates in an arc from the right side to the left side of the needle 10 when the sewing machine is viewed from the front below the needle plate 8. (FIG. 2 (a)). In addition, the long link end 62a of the L-shaped looper drive link 62 is converted into a vertical motion, and the upper looper mounting arm 63 swings about a shaft fulcrum of the upper looper mounting arm 63 with respect to the looper base 67. The upper looper 30 carried by the upper looper mounting arm 63 extends from the right side of the needle 10 when viewed from the front of the sewing machine and below the sword tip 41 of the lower looper 40, to the left side of the needle 10 and above the needle plate 8 when viewed from the front of the sewing machine. (FIG. 2 (a)).
[0078]
The looper clutch 500 for transmitting and interrupting the power from the lower shaft S2 to the looper driving unit 60 transmits the power from the lower shaft S2 to the looper driving shaft 61 at the time of forming the overcast portion 7 so as to transmit the power to the lockstitch portion 6 and the edge. The overlock portion 7 is formed, the upper looper 30 is retracted at the bottom dead center when the lock stitch portion 6 is formed, and power is cut off from the lower shaft S2 to the looper drive shaft 61 to form the lock stitch portion 6 (FIG. 2 (b)). )), And a looper drive screw gear MT3 as a motion conversion mechanism (FIGS. 8 and 9). As shown in FIGS. 8, 9, and 10, the looper drive screw gear MT3 changes the rotational motion from the lower shaft S2 by 90 degrees in the feed direction and then transmits it to the looper drive unit 60. The gear 509 is fixed to the other end of the looper drive shaft 61 rotatably fixed to the looper base 67, and the driving gear 505 is slidably fitted to the lower shaft S2.
[0079]
Further, a looper clutch 500 is fixed to the looper base 67 with screws and is fitted to a concave portion 505b formed at one end of the driving side gear 505, and a looper driving screw gear stopper 503, and is fixed to one end of the lower shaft S2 and fixed to the end surface. A clutch receiver 506 having a clutch engaging recess 506a formed on the other end of the driving gear 505 for fitting a clutch claw 505c, and a driving gear 201 and a looper driving screw gear MT3 of the hook driving screw gear MT2. A clutch spring 508 which is loosely fitted to the lower shaft S2 so as to be located between the driving side gears 505 and resiliently resilient in a direction in which the clutch claws 505c of the driving side gear 505 can engage with the clutch engaging recesses 506a of the clutch receiver 506; Movement formed on the driving side gear 505 of the looper drive screw gear MT3 incorporated in the lockstitch / overlock switching control unit 510 described later. Looper stop timing arm tip 501a fitted to 505a has a looper stop control plate 501 which is formed at one end.
[0080]
The lockstitch / overlock switching control unit 510 in which the looper stop control plate 501 is incorporated includes a clutch switching plate 511 that is overlapped with the looper stop control plate 501 and fixed to be slidable with each other. Specifically, the looper stop control plate 501 is slidable by a predetermined length in the axial direction of the lower shaft S2 on the protrusions 512a and 512b protruding from the lower surface of the shuttle mount 512 fixed to the machine frame FR. A clutch switching plate 511 is fixed to the stop control plate 501 so as to be slidable by a predetermined length in the axial direction of the lower shaft S2. Further, a looper stop control tension spring 514 is stretched between a first spring hook 511a provided on the clutch switching plate 511 and a spring hook 501b provided on the looper stop control plate 501. Further, a clutch switching tension spring 513 is stretched between a second spring hook 511b provided on the clutch switching plate 511 and a spring hook 512c provided on the left end of the shuttle mount 512 in FIG. I have. Thus, the clutch switching plate 511 and the looper stop control plate 501 are constantly repelled leftward in FIG.
[0081]
The lock stitch / overlock switchover control section 510 is controlled by the lock stitch / overlock switchover control section 510 in order to control the switching between the lockstitch and the overlock stitch in conjunction with the stitch selection of the stitch selection device 130. The clutch switching plate 511 is connected to the stitch selection device 130.
[0082]
The stitch selection device 130 has a stitch switching arm 133 whose one end is engaged with an edge overlock cam 132 fixed to a stitch selection shaft 131 and rotates around a stitch switching arm shaft 134 based on the cam shape. One end of a stitch switching rod 135 is connected to the other end of the stitch switching arm 133. A long slot 135a for adjustment is drilled at the other end of the stitch switching rod 135, and a connecting piece 514 is loosely fitted into a connecting hole of a connecting portion 511c formed at one end of the clutch switching plate 511. At 514, a stitch switching rod 135 is fixed with a screw 515 and a washer 516 so as to be position-adjustable with an adjusting slot 135a.
[0083]
In the looper clutch 500 and the lock stitching / overlock switching control unit 510 configured as described above, when performing the overlock stitching, the stitch switching arm 133 is moved by the overlock cam 132 of the stitch selection device 130 in FIG. As the sewing machine rotates clockwise (when the sewing machine is viewed from the front), the seam switching rod 135 connected to the other end of the seam switching arm 133 moves to the left. 501 also moves leftward due to the resilient force of the clutch switching tension spring 513 and the looper stop control tension spring 514. When the looper stop control plate 501 moves leftward, the looper stop timing arm tip 501a of the looper stop control plate 501 fitted in the movement groove 505a of the drive side gear 505 of the looper drive screw gear MT3 moves the drive side gear 505. Moving to the left, the clutch pawl 505c of the driving gear 505 is engaged with the clutch engaging recess 506a of the clutch receiver 506 fixed to the lower shaft S2 (see FIGS. 9A and 10A). . As a result, the rotational motion of the lower shaft S2 is transmitted to the driven gear 509 (see FIG. 4) via the driving gear 505, so that the upper looper 30 and the lower looper 40 of the looper driving unit 60 are driven.
[0084]
In the case of performing the lock stitch, the stitch switching arm 133 is rotated counterclockwise in FIG. 8 (when the sewing machine is viewed from the front) by the overlock cam 132 of the stitch selecting device 130. Since the stitch switching rod 135 connected to the other end of the arm 133 moves rightward, the looper stop control plate 501 is resiliently moved by the clutch switching tension spring 513 and the looper stop control tension spring 514 together with the clutch switching plate 511. Move to the right against the force. When the looper stop control plate 501 moves rightward, the looper stop timing arm tip 501a of the looper stop control plate 501 fitted into the movement groove 505a of the drive side gear 505 of the looper drive screw gear MT3 moves the drive side gear 505. By moving to the right, the concave portion 505b of the driving gear 505 can be fitted to the looper drive screw gear stopper 503 against the resilience of the compression spring 508, and the clutch receiver fixed to the lower shaft S2. The clutch engagement concave portion 506a of 506 is disengaged from the clutch pawl 505c of the driving side gear 505 (FIGS. 9B and 10B). As a result, the rotational motion of the lower shaft S2 is not transmitted to the driving gear 505, so that the driven gear 509 does not rotate, and the upper looper 30 and the lower looper 40 of the looper driving unit 60 stop.
[0085]
The lockstitch overlock sewing machine provided with such a looper drive mechanism 50 further includes a motion conversion mechanism 71 (FIGS. 11 and 12) interlocked with the rotation axis of the lockstitch overlock stitch machine, that is, the upper axis S1. An upper knife 72 that moves up and down through the lower knife 73 that cooperates with the upper knife 72 is provided with a knife driving mechanism 70 that cuts the cloth edge 5c of the cloth 5 (FIG. 2).
[0086]
The knife drive mechanism 70 is provided with a knife drive section 710 pivotally supported by the machine frame FR and slidably guiding the upper knife 72.
[0087]
The motion converting mechanism 71 transmits power to the upper knife 72 when the knife drive unit 710 operates, and pivots the knife drive unit 710 to the retracted position when the knife does not operate to cut off the power to the upper knife 72. It is connected to the upper knife 72 via 75.
[0088]
As shown in FIGS. 1, 11, 12, and 13, the motion conversion mechanism 71 includes four links 76, 77 (78), 79, and 80 that connect the upper shaft S1 as a rotation shaft and the machine frame FR. 4 link 79 using one link 79 of the first four-joint rotary chain LK1 and a node N4 of the machine frame FR, and using the drive unit 751 of the female clutch 75 as another link 82. , 81, 82, and 83, and a second four-node rotating chain LK2. In the first four-bar chain LK <b> 1, a link 78 is fixed to a link 77, and this link 78 is connected to a link 80. The link 76 is a fixed link.
[0089]
In the embodiment shown in FIG. 12, the motion converting mechanism 71 extracts motion from a mechanism for driving the balance 16 up and down from an upper shaft S1 as a rotation axis, converts the motion, and moves the upper knife 72 up and down. However, the movement converting mechanism 71 may take out a movement from a mechanism for driving the needle 10 up and down from the upper axis S1 as a rotation axis, convert the movement, and move the upper knife 72 up and down. The balance 16 is driven up and down by four links 76, 77 (78), 79, 80 from the upper shaft S1.
[0090]
As shown in FIG. 11, the female clutch 75 includes a pin 84 formed on another link 82 as a driving section 751 and a long groove 702 formed on the upper knife 72 as a driven section 701 and into which the pin 84 fits. . The pin 84 is screwed into a mounting hole (not shown) at the bent lower end of the other link 82 as the driving unit 751 with a nut 753 so that the vertical position can be adjusted.
[0091]
As shown in FIG. 14, the knife driving section 710 is provided with a long groove 702 to be fitted to the pin 84 of the driving section 751 and the upper knife driving piece 711 to which the upper knife 72 is fixed, and the upper knife driving piece 711 is arranged in parallel. A female sliding body 712 to be provided, a lower female mounting piece 713 which is provided in parallel with the female sliding body 712 and to which the lower knife 73 is fixed, and these three components are disposed from above with an upper female driving piece 711, a female sliding body 712 and a lower A knife sliding shaft 714 is slidably fitted in the order of the knife mounting piece 713, and the upper knife 72 and the lower knife 73 are arranged so as to be able to cut the cloth.
[0092]
A guide groove 712a is formed in the female sliding body 712 so that the convex portion 713a formed on the lower female mounting piece 713 is slidably fitted in the axial direction of the female sliding shaft 714. A female unit base 715 for movably fixing to the machine frame FR is fixed. The knife unit table 715 has an irregular elliptical trajectory between the operating position on the needle plate 8 when the knife is operated and the retracted position at the lower part of the arm of the sewing machine when the knife is not operated by the four-bar rotating link 730 having different internode lengths. It is pivotally attached to the machine frame FR so as to draw and shift.
[0093]
The four-bar rotation link 730 has an upper swing arm 731 having one end pivotally attached to the upper end of the female unit base 715, and a lower swing arm 732 having one end pivotally attached to the lower end of the female unit base 715. The other end of the arm 731 is pivotally mounted between the upper part of the thread guide plate 733 and the upper part of the female unit mounting plate 734, and the other end of the lower swing arm 732 is located at the lower part of the thread guide plate 733 and the lower part of the female unit mounting plate 734. Axle is mounted between. A female retracting tension spring 736 is stretched between a spring hook 731a provided on the other end side of the upper swing arm 731 and a spring hook 735 provided on the lower side of the female unit mounting plate 734. The female unit mounting plate 734 is fixed to the machine frame FR. Since the four-bar rotation link 730 is configured as described above, the female unit table 715 can be moved by drawing an irregular elliptical trajectory.
[0094]
The female unit base 715 is bent in an L-shape so as to cover two predetermined adjacent surfaces of the female sliding body 712 and the lower female mounting piece 713. Note that the female sliding body 712 is fixed to the female sliding shaft 714 with a screw member such as a screw. In addition, the knife unit base 715 has a knife drive section 710 with an irregular elliptical trajectory between the operating position on the needle plate 8 when the knife is actuated and the retracted position under the arm of the sewing machine when the knife is not actuated by the four-bar rotating link 730. A knob 715f for drawing and shifting is formed.
[0095]
The lower knife mounting piece 713 has a groove 713b, and is engaged with a positioning lever 718 that is loosely fitted in a slit 715c formed in a bent portion of a knife unit base 715 fixed to the knife sliding body 712. ing. More specifically, the positioning lever 718 has a half-pressed convex portion 718a as a rotation axis serving as a fulcrum, and is pivotally supported by a pivot hole 715d formed in the female unit base 715. Further, a protrusion 718b serving as a load point is formed at one end of the positioning lever 718, and is engaged with the groove 713b of the lower knife mounting piece 713. Therefore, since the positioning lever 718 is gripped between the knife unit base 715 and the lower knife mounting piece 713, the operating portion 718c formed at the other end of the positioning lever 718 serving as a force point is operated upward. When rotated, the lower knife mounting piece 713 descends while sliding on the female sliding shaft 714, and when the operating portion 718c is rotated downward by operating, the lower knife mounting piece 713 causes the female sliding shaft 714 to rotate. It will rise while sliding. A concave portion 718d for stopper is formed on the back surface of the convex portion 718b of the positioning lever 718. When the positioning lever 718 is operated upward so that the lower knife 73 is lowered to a predetermined position, the positioning lever 718 protrudes from the female unit base 715. The stopper convex portion 715e is fitted.
[0096]
The lower knife 73 fixed to the lower end portion 713c of the lower knife mounting piece 713 positions the knife driving section 710 in the positioning recess 8a of the needle plate 8 with respect to the needle drop position PS of the needle 10 when the knife is operated. It has a positioning locking portion 87 (see FIG. 21).
[0097]
On the other hand, the upper knife driving piece 711 has a groove 711a, and the upper knife spring plate 719 is fitted in the groove 711a, and is fixed by a screwing member 720 such as a screw. The upper knife spring plate 719 is formed to have a length that extends from the upper knife drive piece 711, and is slidably loosely fitted in the guide groove 712 a of the knife sliding body 712. An upper knife 72 is fixed to a portion 719a of the upper knife spring plate 719 extending from the upper knife driving piece 711 by a screw member 721 such as a screw. The extension portion 719a of the upper knife spring plate 719 is bent so that the elastic force of the upper knife spring plate 719 can be positively applied to press the upper knife 72 against the lower knife 73.
[0098]
According to the scalpel drive mechanism 70 configured as described above, the scalpel drive section 710, which is a scalpel cutting mechanism portion, can be compactly incorporated in the existing structural space of the sewing machine. The operation of performing the overlock sewing and the operation of performing the main sewing without cutting the cloth edge can be easily switched and executed.
[0099]
In addition, the lock-stitch overlock sewing machine transfers the upper looper thread 3 and the lower looper thread 4 to the upper looper 30 and the lower looper 40 in conjunction with the switching control to the lock stitch by the lock-stitch / overlock stitching switching control unit 500. A looper threading device 300 for threading is provided in a table of the sewing machine.
[0100]
As shown in FIGS. 15 and 16, the looper threading device 300 includes an upper looper thread conduit 305, which is a hollow thread guide for sending air supplied from the air pump 304 to the upper looper 30 and the lower looper 40, and a lower looper. The yarn conduit 306, the yarn introduction member 307 connected to the upper looper yarn conduit 305, and the lower looper yarn conduit 306, respectively, and the air from the air pump 304 is supplied to one of the upper looper yarn conduit 305 and the lower looper yarn conduit 306. And a connection switching member 308 for performing switching.
[0101]
The upper looper 30 and the lower looper 40 have a hollow structure from the looper blade tip thread outlets 30b and 40b serving as the blade tips to the looper thread inlets 30a and 40a. The upper looper 30 and the lower looper 40 are composed of looper thread pipes 301 and 401 which are tubular members from the looper blade tip thread outlets 30b and 40b to the looper thread inlets 30a and 40a, and the looper thread inlets 30a and 30a are pressurized air. The upper looper yarn conduit 305 and the lower looper yarn conduit 306 are connected to each other. The receiving portions of the looper thread inlets 30a, 30a are formed in an expanded shape suitable for introducing the looper thread, that is, in a trumpet shape. In addition, the upper looper 30 and the lower looper 40 can also be constituted by hollow members themselves.
[0102]
Further, the upper looper 30, the looper thread inlets 30a and 40a of the lower looper 40, and the thread guide outlets 305b and 306b of the upper looper thread conduit 305 and the lower looper thread conduit 306 intersect with the motion plane drawn by the upper looper 30 and the lower looper 40. It is arranged in the direction. This facilitates processing, assembly, and adjustment to match the looper thread inlets 30a, 40a of the upper looper 30, the lower looper 40 and the thread guide outlets 305b, 306b of the upper looper thread conduit 305, the lower looper thread conduit 306. That's why.
[0103]
The air pump 304 includes a cylinder 304a, a piston 304b that slides in the cylinder 304a, and a lever 304c that slides the piston 304b. The lever 304c is attached in a direction to push down the piston 304b by a spring 304d fixed to the sewing machine main body. It is being rushed. An air supply pipe 304e for sending air is connected to an upper end of the cylinder 304a.
[0104]
When the lever 304c is pushed down in the air pump 304 having such a configuration, the piston 304b is pushed up against the urging force of the spring 304d and sends pressurized air to the air supply pipe 304e. The air supply pipe 304e is connected to the connection switching member 308.
[0105]
As shown in FIGS. 17, 18, and 19, the connection switching member 308 includes two air supply ports 381 and 382 for supplying air to the yarn introduction member 307, and these air supply ports 381 and 382 and the air supply pipe 304e. Is connected to the yarn introducing member 307 such that the surface on which the air supply ports 381 and 382 are formed contacts the yarn introducing member 307. A sealing member such as an O-ring for maintaining airtightness is fitted to the air supply ports 381 and 382.
[0106]
Further, the connection switching member 308 has a projection 384 formed on the surface where the air supply ports 381 and 382 are formed, and the projection 384 is formed with a wavy cutout 371a formed on the surface of the yarn introduction member 307 facing this surface. Engages. Further, the connection switching member 308 is formed integrally with a slide portion 385 and a knob portion 386 which are engaged with a slide groove 371b of a thread introduction member 307 described later. The connection switching member 308 is operated by operating the knob portion 386. It can be slid with respect to the thread introduction member 307 along the slide groove 371b. At this time, the connection switching member 308 is positioned at one of the first and second positions with respect to the thread introduction member 307 by the engagement between the wavy notch 371a of the thread introduction member 307 and the projection 384.
[0107]
The yarn introduction member 307 includes a base 371 connected to the connection switching member 308, a yarn inlet pipe 378, 378 'fitted to the base 371, and a yarn inlet fitted to the yarn inlet pipe 378, 378'. It comprises members 372, 372 'and a mounting plate 373 to which a base 371 fitted with the thread inlet members 372, 372' together with the thread inlet pipes 378, 378 'is screwed. The mounting plate 373 is fixed to the sewing machine body by screwing.
[0108]
As described above, the base 371 is formed with the slide groove 371b in which the slide portion 385 of the connection switching member 308 engages and the waveform notch 371a in which the protrusion 384 engages. A spring 374 and a ball 375 are embedded in the base 371 on the side facing the knob 386, and the spring 374 presses the knob 386 via the ball 375, and the air supply port 381 of the connection switching member 308. , 382 are urged so as to be in close contact with the base 371. Further, the base 371 is provided with two substantially cylindrical concave portions 376 and 376 'into which the thread inlet members 372 and 372' are fitted.
[0109]
The recess 376 (same for 376 ') is connected to the first hole 376a (376'a) into which the yarn inlet tube 378 (378') is inserted and the air supply port 381 (382) of the connection switching member 308. The second hole 376b (376'b) is formed (see FIGS. 17 and 18). When the connection switching member 308 is slid to the first position by the knob 386, the air supply port 381 is positioned so as to coincide with the second hole 376b of the one concave portion 376, and at this time, the air supply port 382 is The second concave portion 376 'is located at a position completely shifted from the second hole 376'b. When the connection switching member 308 is slid to the second position by the knob 386, the air supply port 382 is positioned so as to coincide with the second hole 376'b of the other concave portion 376 '. The air supply port 381 is located at a position completely displaced from the second hole 376b of the concave portion 376. The upper end of the first hole 376a is cut in a conical shape so that the upper part of the yarn inlet tube 378 is engaged.
[0110]
The yarn inlet tube 378 (378'a) has a funnel-shaped receiver at the top for engaging a cut conical part at the top of the first hole 376a (376'a). The thread inlet member 372 (372 ') is engaged with the funnel-shaped receiving portion of the tube 378 (378'). The lower end of the yarn inlet tube 378 (378 ') is connected to the upper looper yarn conduit 305 (lower looper yarn conduit 306) by a connecting rubber 379 (379').
[0111]
The thread inlet member 372 (372 ') has a substantially cylindrical shape having a flange 372a having a diameter substantially equal to the diameter of the recess 376 (376'), and a thread inlet for inserting a thread into the center of the upper end. 372b is formed, and a yarn introduction tube 372c is formed to penetrate the center of the cylinder continuously from the yarn inlet 372b.
[0112]
The base 371 in which the thread inlet members 372, 372 'are fitted via the thread inlet pipes 378, 378' has an O-ring formed in a hole 373a in which the thread inlets 372b, 372'b are formed in parallel with the mounting plate 373. It is screwed to the mounting plate 373 so as to be fitted via a sealing member as described above. The yarn inlets 372b and 372'b have a trumpet shape so that the yarn can be easily inserted.
[0113]
Further, an air flow path of the yarn inlet member 372 will be described. Note that the yarn inlet member 372 'has the same configuration as the yarn inlet member 372, and a description thereof is omitted.
[0114]
The lower end of the thread inlet member 372 has a conical shape which engages with a receiving portion of the thread inlet tube 378 which is fitted into the first hole 376a cut into the concave portion 376, and the outer surface of the cone has at least two or more. Are formed to form the gas introduction portion 377. That is, the end of each gas introduction part 377 is opened to the yarn introduction pipe 372c at the center of the yarn inlet member 372, respectively. Therefore, when the air supply port 381 and the second hole 376b communicate with each other, the air supplied from the air supply port 381 is branched into a plurality of gas introduction portions 377 through the space of the second hole 376b and the concave portion 376. The yarn is introduced into the yarn introduction tube 372c.
[0115]
Here, when the pressurized air is extruded from each gas introduction part 377, the gas introduction part 377 opens at an acute angle to the yarn introduction pipe 372c, so that the flow velocity in the direction of the arrow is high near the outlet. An air flow occurs. Therefore, a force directed in the direction of the arrow is generated on the yarn inlet side of the yarn introduction tube 372c by the Bernoulli's theorem, and the yarn inserted from the yarn inlet 372b is drawn into the upper looper yarn conduit 305 via the yarn inlet tube 378. . It is sent to the yarn outlet of the looper by the flow of air having a high flow rate from the gas introduction part 377. At this time, the pressurized air is branched by the plurality of gas introduction portions 377 and introduced into the yarn introduction tube 372c, so that the yarn inserted into the yarn introduction tube 372c from the yarn inlet 372b can be extremely efficiently transferred to the upper looper yarn conduit 305. Can be sent to the side.
[0116]
When pressurized air is supplied from the yarn introduction pipe 372c to the upper looper yarn conduit 305, the air existing for a long distance from the upper looper yarn conduit 305 to the yarn outlet 30b of the upper looper 30 has resistance and resistance. In order to prevent the pressurized air from being pushed back, the amount of air supplied from the gas introduction portion 377 is such that there is no such resistance and the air is smoothly discharged from the yarn outlet 30b. It is desirable to have a sufficient flow rate. For this reason, when the pipe diameter of the yarn introduction pipe 372c is d2, the sum d1 of the pipe diameters of the gas introduction section 377 is preferably d1 <d2. For example, the pipe diameter of the yarn introduction pipe 372c is 0.8 mm or more. When the distance is about 1 mm, d1 is preferably set to about 80% thereof. By setting the total diameter of the pipes of the gas introduction section 377 in this way, it is possible to obtain a flow velocity sufficient to draw out the yarn with a relatively small amount of air, and to suppress the resistance due to the air in the middle, and to control the upper looper yarn. 3 can be smoothly conveyed to the yarn outlet 30b.
[0117]
As shown in FIGS. 15 and 16, the upper looper yarn conduit 305 and the lower looper yarn conduit 306 are arranged in such a direction that the yarn guide outlets 305b and 306b intersect the movement plane drawn by the upper looper 30 and the lower looper 40. The upper looper yarn guide 311 and the lower looper yarn guide 312 are fixed to the looper base 67 of the looper driving unit 60 so as to be supported. Therefore, the looper thread inlets 30a and 40a of the upper looper 30 and the lower looper 40 are also arranged in a direction crossing the movement plane drawn by the upper looper 30 and the lower looper 40. The yarn inlets 30a and 40a can be matched with the yarn guide outlets 305b and 306b of the upper looper yarn conduit 305 and the lower looper yarn conduit 306. Since the looper thread inlets 30a and 40a of the upper looper 30 and the lower looper 40 are formed in a trumpet shape (tapered wall surface), the upper looper thread conduit 305 and the lower looper thread conduit 306 are connected to the looper thread inlets 30a and 40a. , The center of the upper looper thread conduit 305 and the center of the lower looper thread conduit 306 and the center of the looper (looper thread pipes 301 and 401) can be eliminated, and the centers can be matched.
[0118]
Next, a connecting means for connecting the upper looper yarn conduit 305 and the lower looper yarn conduit 306 to the looper yarn inlets 30a and 40a of the upper looper 30 and the lower looper 40 will be described. As shown in FIG. 4, FIG. 8, FIG. 9, FIG. 15, and FIG. 16, the yarn conduit disengagement lever 321, yarn conduit disengagement lever link 322, dissociation lever base 323, torsion spring 324 for disengagement lever, yarn conduit disassembly It is constituted by a claw plate 325 and tension springs 326 and 327 for thread conduits. One end of the thread conduit disengaging lever 321 is disposed so as to be able to press against the upper looper thread conduit 305 and the thread guide outlets 305b, 306b side of the lower looper thread conduit 306, and the other end is connected to the looper base 67 of the looper driving unit 60. The intermediate portion is rotatably mounted on one end of a thread conduit disengaging lever link 322. Further, since the yarn conduit disengaging lever 321 is always repelled so as to be separated from the upper looper yarn conduit 305 and the lower looper yarn conduit 306, a disengaging lever is provided between the yarn conduit disengaging lever 321 and the yarn conduit disengaging lever link 322. A torsion spring 324 is provided. Further, the other end of the thread conduit disengaging lever link 322 is connected to one end of a thread conduit disengaging claw plate 325 which is rotatably fixed to a convex portion 512c formed on the hook mount 512 of the lockstitch / overlock switchover control unit 510. It is connected to.
[0119]
A thread conduit disengaging claw 325a is formed at the other end of the thread conduit disengaging claw plate 325, and the thread conduit connection claw which is cut off in the clutch switching plate 511 and the looper stop control plate 501 of the lockstitch / overlock switching control unit 510. The release cam 511d and the yarn conduit contact / separation timing cam 501c can be engaged.
[0120]
Further, one end of the tension spring 326 (327) for the yarn conduit is fixed to the machine frame FR, and the other end is hooked on the upper looper yarn conduit 305 (the lower looper yarn conduit 306). Therefore, the upper looper yarn conduit 305 (the lower looper yarn conduit 306) always connects the yarn guide outlets 305b, 306b by the elastic force of the yarn conduit tension springs 326 (327) to the looper yarns of the upper looper 30 and the lower looper 40. The inlets 30a and 40a can be pressed against each other.
[0121]
According to the looper threading device 300 configured as described above, when the stitch selection of the stitch selection device 130 is performed other than the overlock stitching, the lockstitch / overlock stitching switching control unit 510 automatically performs the operation other than the overlock stitching. Since the switching control is performed, the looper threading device 300 can thread the upper looper thread 3 and the lower looper thread 4 through the upper looper 30 and the lower looper 40 in conjunction with the switching control.
[0122]
Further, a connection portion between the upper looper 30, the lower looper 40, the upper looper thread conduit 305, and the lower looper thread conduit 306 of the threading automatic device 300, that is, the upper looper 30, the looper thread inlets 30a, 40a of the lower looper 40 and the upper looper A looper thread balance 400 (see FIGS. 3, 4, and 15) as looper thread supply means is provided between the thread conduit 305 and the thread guide outlets 305b, 306b of the lower looper thread conduit 306. In this looper thread balance 400, the upper looper thread 3 and the lower looper thread 4 are interlocked with the movement trajectories of the upper looper 30 and the lower looper 40 in accordance with the switching control to the overlock stitching by the lockstitch / overlocking switching control section 510. The upper looper thread 3 and the lower looper thread 4 necessary for the overlock sewing when the loop is looped around the needle 10 are fed through the upper looper thread tensioner 35 and the lower looper thread tensioner 45 (see FIG. 1). After the needle 10 is removed from the upper looper thread 3 and the lower looper thread 4 and the upper thread 1 is thread-tightened by the upper thread balance 16, the upper looper thread 3 and the lower looper which have been threaded and stored are stored. The yarn 4 is supplied to the upper looper 30 and the lower looper 40.
[0123]
5 and 6, when the upper looper 30 descends and the looper thread inlet 30a passes through the thread guide outlet 305b of the upper looper thread conduit 305, the upper looper thread 3 moves the needle 10 The upper looper 30 reaches the bottom dead center after the upper looper 30 is further lowered and the thread tightening of the upper looper thread 3 is completed, and before the needle 10 comes off the sewing object. The upper looper thread 3 is fed through an upper looper thread tensioner 35 (see FIG. 1) to accumulate the yarn, and when the upper looper 30 starts to ascend, the accumulated upper looper yarn 3 is released, and the upper looper 30 is released. When the needle 10 descends from the top dead center when the needle 10 descends from the top dead center when rising and passing the upper looper top dead center, the upper looper that performs threading so as to apply tension to the upper looper thread 3 A thread balance 401 (see FIGS. 5A and 5B); When the looper 40 is retracted and the looper thread inlet 40a passes through the thread guide outlet 306b of the lower looper thread conduit 306, the lower looper thread 4 is entangled with the needle 10, and the lower looper thread 4 starts to be tightened. After the lower looper thread 4 is retracted and the thread tightening of the lower looper thread 4 is completed, the lower looper thread 4 is fed in through the lower looper thread tensioner 45 (see FIG. 1) until the lower looper 40 reaches the final retreat point, and the lower looper thread 4 is stored. A lower looper thread balance 402 (see FIGS. 6A and 6B) that discharges the accumulated yarn when the looper 40 moves forward is provided. Thereby, in the overlock sewing, when the needle 10 is pierced through the body to be sewn, the upper looper thread 3 and the lower looper thread 4 previously stored by the upper looper thread tensioner 35 and the lower looper thread tensioner 45. Can be tightened.
[0124]
As shown in FIG. 4, the upper looper thread balance 401 has a looper balance driving arm 404 having one end mounted on a looper base 67 fixed to the machine frame FR and having a shift driving cam groove 403, and And a cam driver 405 provided on the lower looper drive arm 66 for slidingly driving the looper balance drive arm 404 by the looper drive section 60. On the other hand, the lower looper thread balance 402 is provided at one end of the looper balance driving arm 404.
[0125]
As shown in FIG. 20, a lock stitch overlock sewing machine is provided on the needle plate 8 and is an openable and closable hatch that closes the opening 8b of the needle plate 8 in conjunction with the switching control of the lock stitch / overlock switch control unit 510. 601 and the upper looper 30 are opened and lowered when the upper looper 30 moves up and down the needle plate 8 in conjunction with the switching control to the overlock stitching of the lockstitch / overlock stitching switching control unit 510 (FIG. 20A). Hatch opening / closing for opening / closing the hatch 601 so that the upper looper 30 is closed when the upper looper 30 is retracted to the home position in conjunction with the overlocking switching control unit 510 switching control to lockstitching (FIG. 20B). 602.
[0126]
According to the hatch 601 configured as described above, when the stitch selection of the stitch selection device 130 is set to the overlock stitching, the lockstitch / overlock stitching switching control unit 510 automatically switches to the overlock stitching. The hatch 601 provided on the needle plate 8 can be opened when the upper looper 30 is moved up and down the needle plate 8 in conjunction with the switching control to the overlock sewing of the lockstitch / overlock switching control unit 510. Further, according to the hatch opening / closing section 602, when the lockstitch / overlock switchover control section 510 is switched to the lockstitch, the hatch opening / closing is performed when the upper looper 30 is retracted to a fixed position below the needle plate 8. Since the part 602 can automatically close the hatch 601, the operation of opening and closing the lid for closing the opening 8 b formed in the needle plate 8 in order to raise and lower the upper looper 30 up and down the needle plate 8 is performed. Can be omitted and also after removing the lid It is possible to save the trouble for accommodating managing the lid can prevent an accident of losing the lid.
[0127]
The hatch opening / closing portion 602 is opened when the upper looper 30 moves up and down the needle plate 8 in conjunction with the switching control to the overlock stitching of the lockstitch / overlock stitching switching control portion 510, and the stitch / overlock stitching is performed. When the upper looper 30 retreats to the home position in conjunction with the switching control to the lockstitching by the switching control unit 510, the looper clutch 500 is completely disengaged, the power to the upper looper 30 is shut off, and the hatch 601 is closed. Hatch opening / closing spring 604 is provided so as to interlock with the lockstitch / overlock switching control unit 510. Specifically, the hatch opening / closing spring 604 is fixed to a hatch opening / closing spring mounting plate 605 fixed to the other end of the looper stop control plate 501 of the lockstitch / overlock switching control unit 510. A hatch opening / closing drive claw 604 a is formed at the tip of the hatch opening / closing spring 604, and is engaged with a hatch opening / closing claw 606 provided inside the hatch 601. Thus, the hatch 601 can be automatically opened and closed by the elasticity of the hatch opening and closing spring 604 provided in the hatch opening and closing unit 602.
[0128]
Further, the hatch 601 is viewed in the sewing direction by looking at the cloth debris cut off during the overlock sewing of the edge of the upper looper thread 3 pierced by the upper looper 30 ascending and descending in the opening 8b formed when the hatch 601 is opened. When the hatch 601 is closed, a cloth waste guide plate 603 constituting the same surface as the needle plate 8 is hinged together with the hatch 601 when the hatch 601 is closed. The torsion spring for the hatch hinge is provided at the hinge portion between the cloth waste guide plate 603 and the hatch 601 so that the cloth waste guide plate 603 is always repelled so that the hatch 601 can be supported when the hatch 601 is opened. 608 are provided. Further, the hatch 601 is provided with a hatch stopper 607 so as to be locked at the position when the hatch 601 is opened at a predetermined opening. The hatch stopper 607 is adapted to be hooked on the end face of the opening 8b of the needle plate 8.
[0129]
A lock stitch overlock operation by a so-called home lock stitch overlock sewing machine to which the stitch forming apparatus of the sewing machine configured as described above is applied will be described below.
[0130]
As shown in FIG. 2, the stitches of the overlock stitch include a lock stitch portion 6 including an upper thread 1 and a lower thread 2 and an upper looper thread 3 and a lower looper thread 4 which are two looper threads. It has an overhang portion 7 and is formed by the lock stitch portion 6 and the overhang portion 7 intersecting each other. That is, the upper thread 1 and the lower thread 2 form seams 1a and 2a parallel to the cloth surface on the upper surface 5a and the lower surface 5b of the cloth to be sewn, for example, the two-ply cloth 5, respectively. The stitches 6 are formed by forming stitches that cross the cloth 5 in the vicinity of the center in the thickness direction.
[0131]
On the other hand, the upper looper yarn 3 and the lower looper yarn 4 form an overhang portion 7 for preventing the edge portion 5c of the cloth 5 from fraying. Passes through the upper surface 5a of the cloth 5 and intersects with the upper end of the lock stitch portion 6, and the lower looper thread 4 passes through the lower surface 5b of the cloth 5 and crosses with the lower end of the lock stitch portion 6.
[0132]
As described above, the stitch of the overlock stitch is composed of the upper thread 1 which is one needle thread, the lower thread 2 which is a hook thread, and the two looper threads 3 and 4. With respect to the lock stitch portion 6 formed by the thread 2, the overlock portion 7 formed by the looper threads 3 and 4 intersects on both surfaces of the cloth, and both the lock stitch and the overlock portion are connected to form a seam. ing.
[0133]
In such a lockstitch overlock sewing machine that forms a stitch formed by connecting both the lockstitch and the overlock stitch, when the sewing operator selects the overlock stitch, the upper thread 1 and the lower thread are used. 2. The threading operation to the upper looper thread 3 and the lower looper thread 4, the stitch switching operation to the overlock stitch, and the knife switching operation to the knife operating state are performed.
[0134]
The threading operation of the upper thread 1 and the lower thread 2 is performed by hooking the upper thread 1 wound on the upper thread spool onto the upper thread tensioner 15 and the upper thread balance 16 and passing the needle 1 through the needle 10, and passing the lower thread 2 through the needle plate. It is pulled out from a shuttle (sword point) 20 located below the bottom 8.
[0135]
Next, the threading operation of the upper looper thread 3 and the lower looper thread 4 is performed by the sewing operator selecting items other than the overlock stitches with the stitch switching knob NB. When the sewer selects an item other than the overlock stitch and rotates the stitch switching knob NB, the stitch selection knob 130 is fixed to the stitch selection shaft 131 of the stitch selection device 130 except for the concave portion 132a. One end of the stitch switching arm 133 is pushed up, and the stitch switching arm 133 rotates counterclockwise in FIG. 8, so that the stitch switching rod 135 connected to the other end of the stitch switching arm 133 moves rightward. As a result, the clutch switching plate 511 of the lockstitch / overlock switching control unit 510 connected to the stitch switching rod 135 moves rightward against the elasticity of the clutch switching tension spring 513. At this time, the looper stop control plate 501 also tries to move rightward against the repulsive force of the looper stop control tension spring 514, but the concave portion 505b of the driving side gear 505 of the looper drive screw gear MT3 and the looper base If the looper drive screw gear stopper 503 fixed to the base 67 is not at the same position, they cannot be fitted, so that the looper stop control plate 501 does not move even by the elastic force of the looper stop control tension spring 514 ( 8, 9, and 10). This is because the looper stop control plate 501 is fixed to the protrusions 512a and 512b protruding from the lower surface of the hook mounting base 512 so as to be slidable in the axial direction of the lower shaft S2 by a predetermined length. This is because the long holes 501d and 501e drilled in the hole allow the clutch switching plate 511 to move.
[0136]
Accordingly, if the upper looper 30 in which the concave portion 505b of the driving side gear 505 and the looper driving screw gear stopper 503 are fitted rotates the hand pulley HP fixed to the upper shaft S1 to the timing position at the lowest point, the looper stop control is performed. Since the plate 501 moves rightward due to the elasticity of the looper stop control tension spring 514, the L-shaped tip 501 a of the clutch switching link 501 fitted in the moving groove 505 a of the driving gear 505 connects the driving gear 505. Can be moved to the right. As a result, the clutch pawl 505c of the driving gear 505 is disengaged from the clutch engaging recess 506a of the clutch receiver 506 fixed to the lower shaft S2, and the rotational movement of the lower shaft S2 is interrupted, so that the driving gear 505 cannot rotate. Therefore, the upper looper 30 and the lower looper 40 of the looper driving unit 60 can be retracted to a predetermined position below the needle plate 8.
[0137]
In such a state, since the thread conduit contact / separation timing cam 501c of the looper stop control plate 501 and the thread conduit contact / separation cam 511d of the clutch switching plate 511 coincide with each other and are located rightward, the thread conduit disengagement / disconnection of the connecting means is performed. Since the thread conduit disengaging claw 325a of the claw plate 325 falls into the cams 501c and 511d, the thread conduit disengaging lever link 322 connected to the thread conduit disengaging claw plate 325 causes the thread conduit disengaging lever 321 to disengage the torsion spring 324 for the disengaging lever. Is separated from the upper looper yarn conduit 305 and the lower looper yarn conduit 306 against the repelling force of As a result, the upper looper yarn conduit 305 and the lower looper yarn conduit 306 move the yarn guide outlets 305b and 306b to the upper looper 30 and the looper yarn inlets 30a and 40a of the lower looper 40 by the elasticity of the yarn conduit tension springs 326 and 327. Press. At this time, since the receiving portions of the looper yarn inlets 30a and 40a have a trumpet shape, the ends of the upper looper yarn conduit 305 and the lower looper yarn conduit 306 naturally have the center of the upper looper yarn pipe 301, The center of the lower looper yarn pipe 401 coincides with the center.
[0138]
Next, the knob 386 of the connection switching member 308 is slid left (or right) so that one air supply port, for example, the left air supply port 381 coincides with the hole 376 b on the upper looper yarn conduit 305 side of the yarn introduction member 307. To do. In this state, the upper looper thread 3 wound around the upper looper thread spool (not shown) is passed through the upper looper thread tensioner 35 to an appropriate length (about 1 cm). ) At the same time, press down the lever 304c of the air pump 304 to send pressurized air to the upper looper yarn conduit 305. This flow of pressurized air generates a negative pressure that draws the yarn near the yarn introduction tube 372c by Bernoulli's theorem, and simultaneously draws the upper looper yarn 3 inserted from the yarn inlet 372b into the upper looper yarn conduit 305. The flow of the pressurized air sends the upper looper thread 3 along the looper side of the upper looper thread conduit 305, the upper looper thread pipe 301, and the thread transport path, and sends it at once from the blade point 31 of the upper looper 30. In the case where the thread cannot be fed by one operation of pressing the lever of the air pump 304, the threading can be reliably performed by repeating the operation two or three times.
[0139]
Next, the knob 386 of the connection switching member 308 is slid to the right so that the air supply port 382 is aligned with the hole 376 ′ b on the lower looper yarn conduit 306 side of the yarn introduction member 307. Here, the lower looper thread 4 wound around the lower looper thread spool (not shown) is inserted into the lower looper thread slot 372'b through the lower looper thread tensioner 45, and the lever of the air pump 304 is operated. The lower looper thread 4 can be sent to the point of the lower looper 40 at a stretch by pushing down 304c and pressurized air.
[0140]
In addition, not only an air pump but also any other apparatus that can send gas at an appropriate flow rate may be used.
[0141]
The stitch switching operation is performed by rotating the stitch switching knob NB in order to select the overlock stitch by the sewing operator, and the concave portion 132 a of the overlock cam 132 fixed to the stitch selection shaft 131 of the stitch selection device 130. Since one end of the seam switching arm 133 is dropped, the seam switching arm 133 rotates clockwise in FIG. 8, so that the seam switching rod 135 connected to the other end of the seam switching arm 133 moves leftward. , And the clutch switching plate 511 of the lockstitch / overlock switching control unit 510 connected to the stitch switching rod 135 moves leftward due to the elastic force of the clutch switching tension spring 513. When the clutch switching plate 511 moves to the left, the looper stop control plate 501 also moves to the left by the elastic force of the looper stop control tension spring 514, so that the moving groove of the driving side gear 505 of the looper drive screw gear MT3. The looper stop timing arm tip 501a of the looper stop control plate 501 fitted to the looper stop 505a moves the driving side gear 505 leftward, and the concave portion 505b of the driving side gear 505 is dissociated from the looper driving screw gear stopper 503, and The clutch pawl 505c of the driving gear 505 engages with the clutch engaging recess 506a of the clutch receiver 506 fixed to the lower shaft S2 (FIG. 9A). When the clutch engagement recess 506a of the clutch receiver 506 is located at a position where the clutch pawl 505c of the driving gear 505 cannot be engaged, the clutch of the clutch receiver 506 fixed to the lower shaft S2 by rotating the hand pulley HP. The engaging recess 506a and the clutch pawl 505c of the driving gear 505 are engaged. Accordingly, the rotational motion of the lower shaft S2 is transmitted to the driven gear 509 via the driving gear 505, so that the upper looper 30 and the lower looper 40 of the looper driving unit 60 are driven.
[0142]
Further, since the thread conduit separating / separating cam 511d of the clutch switching plate 511 is moving to the left, the thread conduit releasing claw 325a of the thread conduit releasing claw plate 325 of the connecting means is connected to the thread conduit releasing / separating cam 325 of the clutch switching plate 511. 511d, it rotates counterclockwise, so that the thread conduit disengaging lever link 322 connected to the thread conduit disengaging claw plate 325 causes the thread conduit disengaging lever 321 to be repelled by the torsion spring 324 for the disengaging lever, thereby forming the upper looper. The yarn conduit 305 and the lower looper yarn conduit 306 are pressed. As a result, the upper looper thread conduit 305 and the lower looper thread conduit 306 move the thread guide outlets 305b and 306b into the upper looper 30 and the looper thread inlet 30a of the lower looper 40 against the elasticity of the thread conduit tension springs 326 and 327. , 40a.
[0143]
Further, since the hatch opening / closing spring mounting plate 605 fixed to the other end of the looper stop control plate 501 that has moved to the left also moves to the left, the hatch opening / closing spring 604 fixed to the hatch opening / closing spring mounting plate 605 is not shown. As shown in FIG. 20A, the hatch opening / closing drive claw 604a is separated from the hatch opening / closing claw 606 of the hatch 601, so that the hatch 601 and the cloth dust guide plate 603 are resilient by the torsion spring 606 for the hatch hinge and the hatch stopper 607. Until it catches on the end face of the opening 8b of the needle plate 8.
[0144]
In the knife switching operation, the knife drive unit 710 is in the knife non-operating state (the retracted position at the lower part of the arm of the sewing machine) as shown in FIG. In this case, the knife drive unit 710 is set to the knife operating state (operating position on the needle plate 8) by the knob 715f formed on the knife unit base 715 of the knife driving unit 710. That is, when the knob 715f is lowered, the upper swing arm 731 and the lower swing arm 732 of the four-bar rotation link 730 move downward while drawing an irregular elliptical trajectory as shown in FIGS. 22, 23, and 24. Then, it smoothly moves to the operating position on the needle plate 8. At this time, the repulsion of the female retraction tension spring 736 stretched between a spring hook 731a provided on the other end side of the upper swing arm 731 and a spring hook 735 provided on the lower side of the female unit mounting plate 734. Since the spring hook 731a of the upper swing arm 731 is locked by the first spring hook locking section 734a of the female unit mounting plate 734 by the force, the knife drive section 710 can be prevented from returning. Here, as shown in FIG. 25A, the positioning lever 718 of the knife driving unit 710 is lowered to a predetermined position, and the lower knife 73 is in a non-operating state in which the lower knife 73 is retracted to the retracted position by the lower knife mounting piece 713. If so, the positioning lever 718 is operated upward as shown in FIG. As a result, the lower knife 73 fixed to the lower knife mounting piece 713 having the groove 713b in which the projection 718b of the positioning lever 718 is fitted is lowered, and the positioning locking portion 87 of the lower knife 73 is moved by the needle. A knife operating state (FIG. 24) in which the knife driving section 710 is fitted to the positioning recess 8a of the plate 8 and positioned with respect to the needle drop position PS of the needle 10 is obtained. At this time, the stopper convex portion 715e projecting from the female unit base 715 is fitted into the stopper concave portion 718d formed on the positioning lever 718 in a state where the stopper convex portion 715e can be detached with a predetermined force. Can be prevented.
[0145]
In the state where the upper looper 30, the lower looper 40, the upper knife 72, and the lower knife 73 of the looper driving unit 60 can be driven in this manner, the lockstitch portion 6 moves the upper thread 1 pierced through the needle 10 with the needle bar. After penetrating the cloth 5 following the vertical movement of the needle 10 by the part MT1, the needle point 21 of the shuttle 20 scoops the needle thread 1 at the point R when the needle 10 starts to rise from the bottom dead center. When the upper thread 1 is pulled up by the needle 10 and the balance 16 which intersect with the lower thread 2 and return further upward, the upper thread 1 is formed by pulling up the lower thread 2, and the above operation is repeated every time the cloth is fed. A continuous lock stitch 6 is formed (FIG. 2).
[0146]
In addition, when the upper looper 30 at the top dead center is reciprocated up and down by the upper looper mounting arm 63, the upper looper thread 3 is firstly scooped by the needle 10 at the point P descending. The upper end of the lockstitch portion 6 and the upper looper thread 3 intersect at the upper surface of the cloth (FIGS. 2, 5A and 5B). Next, when the lower looper mounting arm 65 reciprocates left and right, the lower looper thread 4 of the lower looper 40 that moves from the most protruding point to the last retreat point is scooped by the needle 10 descending from the top dead center at point Q. As a result, the lower end of the lockstitch portion 6 and the lower looper thread 4 intersect at the lower surface of the cloth (FIGS. 2, 6A and 6B). Further, when the lower looper mounting arm 65 reciprocates left and right, the lower looper thread 4 that retreats to the last retreat point moves upward from the lower dead center by the upper looper mounting arm 63 at the point S. As a result, the upper looper thread 3 and the lower looper thread 4 intersect at the edge 5c of the cloth 5 to form an overcast portion 7 (FIG. 2). The overlock portion 7 is also repeated with one cloth feed as one cycle, so that a stitch in which the overlock portion 7 intersects every single stitch as shown in FIG. 27A is obtained. .
[0147]
As shown in FIG. 7 and FIG. 26, when the crank 61a of the looper driving unit 60 rotates, the upper looper 30 and the lower looper 40 drive the L-shaped looper drive link 62 connected to the crank 61a. Therefore, the upper looper mounting arm 63 connected to the long link end 62a of the L-shaped looper drive link 62 converts the constant speed rotation of the looper drive shaft 61 into the swinging motion of the upper looper 30. The short link end 62b of the looper drive link 62 is restricted by a four-joint rotating chain formed by the crank 61a attached to the looper drive shaft 61, the upper looper mounting arm 63, and the long link of the L-shaped looper drive link 62. Since the constant velocity elliptical motion is generated, the lower looper mounting arm 65 connected via the lower looper drive link 64 and the lower looper drive arm 66 rotates the looper drive shaft 61. Converting the dynamic unequal speed swinging movement of the lower looper 40.
[0148]
Here, the upper looper mounting arm 63 is located at the position A. ₁ (Top looper 30 is at bottom dead center) from position C ₁ (The upper looper 30 moves up and down between the upper dead center), and the lower looper mounting arm 65 moves to the position B. ₃ (Lower looper 40 is the last retreat) to position D ₃ (The lower looper 40 moves forward and backward), but the upper looper mounting arm 63 is governed by the constant speed rotation of the coupling portion 62c of the L-shaped looper drive link 62, and the lower looper mounting arm 65 is Since the lower looper 4 is controlled by the unequal-velocity elliptical motion of the short link end 62b of the looper drive link 62, the lower looper 4 performs the swinging motion with a delay with respect to the upper looper 30 (FIGS. 7 and 26). Thus, when the distal end of the upper looper 30 and the distal end of the lower looper 40 intersect, they can be rocked so as not to collide, so that the structural design of the upper looper 30 and the lower looper 40 is facilitated.
[0149]
The upper looper thread 3 and the lower looper thread 4 supplied to the upper looper 30 and the lower looper 40 are loosened or tightened by the upper looper thread balance 401 and the lower looper thread balance 402 of the looper thread balance 400. . Specifically, the upper looper thread balance 401 and the lower looper thread balance 402 of the looper thread balance 400 are controlled by the cam action of the cam driver 405 provided on the lower looper drive arm 66 and the speed change drive cam groove 403. That is, by this cam action, the upper looper thread balance 401 causes the upper looper thread 3 to entangle with the needle 10 when the upper looper 30 descends and the looper thread inlet 30a passes through the thread guide outlet 305b of the upper looper thread conduit 305. After tightening of the looper thread 3 is started and the upper looper 30 further descends and the thread tightening of the upper looper thread 3 is completed, the upper looper 30 reaches the bottom dead center and the upper looper thread before the needle 10 comes out of the sewing object. The upper looper thread 3 is fed in via the tensioner 35 (see FIG. 1) and stored, and when the upper looper 30 starts to rise, the stored upper looper thread 3 is released, and the upper looper 30 rises and the upper looper 30 rises. When the needle 10 descends from the top dead center after passing through the top dead center, the stringing can be performed so as to apply tension to the upper looper thread 3 when the needle 10 scoops the upper looper thread 3 (FIG. 5). (See (a) and (b).) Also, due to this cam action, the lower looper thread balance 402 causes the lower looper thread 4 to be entangled with the needle 10 when the lower looper 40 retreats and the looper thread inlet 40a passes through the thread guide outlet 306b of the lower looper thread conduit 306. The threading of the looper thread 4 is started, the lower looper 40 is further retracted, and after the threading of the lower looper thread 4 is completed, the lower looper thread tensioner 45 (see FIG. 1) is operated until the lower looper 40 reaches the last retreat point. The lower looper thread 4 is fed through the lower looper 40 to accumulate the yarn, and the accumulated yarn can be released when the lower looper 40 advances (see FIGS. 6A and 6B). Thereby, in the overlock sewing, when the needle 10 is pierced through the sewn body, the upper looper thread 3 and the lower looper thread 4 previously stored by the upper looper thread tensioner 35 and the lower looper thread tensioner 45. Can be tightened.
[0150]
In addition, the rotational motion of the rotating shaft of the sewing machine, that is, the upper shaft S1 in the illustrated example, is converted into a vertical motion through a motion converting mechanism 71 that is linked thereto (see FIGS. 1, 3, 11, 12, and 12). 13). That is, when the upper shaft S1 rotates, the links 77 and 78 of the first four-node rotating chain LK1 are cranked, the link 80 is a connecting rod, and the link 79 is rocked as a rocker arm. The swing of the link 79 swings the link 81 of the second four-node rotating chain LK2, and the link 82, and thus the drive 751 of the clutch 75, moves up and down. The motion trajectory of the link 82 draws an elliptical trajectory by the four-bar rotating chain mechanism LK1 and LK2, and a guide plate 755 fixed to the machine frame FR by drawing a trajectory of an approximate straight line in a vertical direction at a PL point near the drive unit 751. The guide pin 754 fixed at the PL point of the link 82 through the guide elongated hole supports the recoil from the knife drive unit 710. As a result, the movement of the drive unit 751 in the horizontal direction is restricted, and only the vertical movement is obtained with a stroke t (FIG. 12) for one rotation of the upper shaft S1.
[0151]
The up-down motion converted by the motion converting mechanism 71 is transmitted via the long groove 702 in which the pin 84 of the driving portion 751 of the clutch 75 and the pin 84 of the upper knife driving piece 711 of the knife driving portion 710 as the driven portion 701 are fitted. And transmitted to the upper knife 72. In the scalpel operating state (FIG. 24), the positioning and locking portion 87 of the lower knife 73 is fitted into the positioning recess 8a of the needle plate 8 to position the scalpel drive portion 710 with respect to the needle drop position PS of the needle 10. The upper knife 72 is slidably guided by a guide groove 712a of a knife sliding body 712 via an upper knife spring plate 719 by an upper knife drive piece 711 pivotally supported by the machine frame FR. In this scalpel operating state, the scalpel drive section 710 is maintained in a vertical state, and since the longitudinal direction of the long groove 702 is oriented in the horizontal direction, power is transmitted between the pin 84 of the drive section 751 of the clutch 75 and the long groove 702 of the driven section 701. The power is transmitted to the upper knife 72 when the knife drive unit 710 operates, and the upper knife 72 and the lower knife 73 cooperating with the upper knife cut the cloth edge 5c of the cloth 5 by this vertical movement.
[0152]
In this manner, by cutting the cloth edge 5c of the cloth 5 and performing zigzag sewing or the like, the overcast sewing operation can be performed in the same manner.
[0153]
Next, when the sewer selects a lockstitch, the threading operation to the upper thread 1 and the lower thread 2, the switching operation to the lockstitch, and the cutting of the cloth edge 5 c of the cloth 5 are performed. If it is desired to perform only the lockstitch without performing the knife switching operation, the knife is switched to the knife non-operation state.
[0154]
The threading operation of the upper thread 1 and the lower thread 2 is performed by hooking the upper thread 1 wound on the upper thread spool onto the upper thread tensioner 15 and the upper thread balance 16 and passing the needle 1 through the needle 10, and passing the lower thread 2 through the needle plate. It is pulled out from a shuttle (sword point) 20 located below the bottom 8.
[0155]
The stitch switching operation is performed by rotating the stitch switching knob NB in order to select the final stitch by the sewing operator, and the concave portion 132 a of the edge overlock cam 132 fixed to the stitch selection shaft 131 of the stitch selection device 130. One end of the seam switching arm 133 is pushed up to the other part, and the seam switching arm 133 rotates counterclockwise in FIG. 8, so the seam switching rod 135 connected to the other end of the seam switching arm 133. Is pulled to the right, and the clutch switching plate 511 of the lockstitch / edge overlock switching control unit 510 connected to the stitch switching rod 135 moves rightward against the elasticity of the clutch switching tension spring 513. Go to At this time, the looper stop control plate 501 also tries to move rightward against the repulsive force of the looper stop control tension spring 514, but the concave portion 505b of the driving side gear 505 of the looper drive screw gear MT3 and the looper base If the looper drive screw gear stopper 503 fixed to the base 67 is not at the same position, they cannot be fitted, so that the looper stop control plate 501 does not move due to the elastic force of the looper stop control tension spring 514 (FIG. 8, FIG. 9, FIG. 10). This is because the looper stop control plate 501 is fixed to the protrusions 512a and 512b protruding from the lower surface of the hook mounting base 512 so as to be slidable in the axial direction of the lower shaft S2 by a predetermined length. This is because the long holes 501d and 501e drilled in the hole absorb the movement of the clutch switching plate 511.
[0156]
Accordingly, if the upper looper 30 in which the concave portion 505b of the driving side gear 505 and the looper driving screw gear stopper 503 are fitted rotates the hand pulley HP fixed to the upper shaft S1 to the timing position at the lowest point, the looper stop control is performed. Since the plate 501 moves rightward due to the elasticity of the looper stop control tension spring 514, the L-shaped tip 501 a of the clutch switching link 501 fitted in the moving groove 505 a of the driving gear 505 connects the driving gear 505. Can be moved to the right. As a result, the clutch pawl 505c of the driving gear 505 is disengaged from the clutch engaging recess 506a of the clutch receiver 506 fixed to the lower shaft S2, and the rotational movement of the lower shaft S2 is interrupted, so that the driving gear 505 cannot rotate. Therefore, the upper looper 30 and the lower looper 40 of the looper driving unit 60 can be retracted to a predetermined position below the needle plate 8.
[0157]
Since the hatch opening / closing spring mounting plate 605 fixed to the other end of the looper stop control plate 501 that has moved rightward also moves rightward, the hatch opening / closing spring 604 fixed to the hatch opening / closing spring mounting plate 605 is shown in FIG. As shown in (b), the hatch 601 of the hatch 601 is pulled by the hatch opening / closing drive claw 604a to close the hatch 601. At this time, the cloth waste guide plate 603 hinged to the hatch 601 also forms the same plane as the needle plate 8 together with the hatch 601 against the resilience of the torsion spring 608 for the hatch hinge. Thus, it is possible to prevent the cloth waste from falling into the opening 8b of the needle plate 8 and adversely affecting the upper looper 30, the lower looper 40, and the like.
[0158]
In the scalpel switching operation, when it is desired to perform only the main sewing without cutting the cloth edge 5c of the cloth 5, the scalpel drive unit 710 is in the scalpel operation state (the operation position on the needle plate 8) as shown in FIG. If so, the positioning lever 718 is operated downward. As a result, the lower knife 73 fixed to the lower knife mounting piece 713 is raised, and the positioning locking portion 87 of the lower knife 73 is released from the state in which the positioning locking portion 87 is fitted into the positioning recess 8 a of the needle plate 8. (See FIG. 25). Then, the knife drive unit 710 is set to a non-operating state of the knife (a retracted position at the lower part of the arm of the sewing machine) by a knob 715f formed on the knife unit base 715 of the knife drive unit 710. That is, when the knob 715f is lowered upward, the upper swing arm 731 and the lower swing arm 732 of the four-bar rotating link 730 move upward while drawing an irregular elliptical trajectory as shown in FIGS. 24, 23 and 22. And smoothly move to the retracted position under the arm of the sewing machine. At this time, the repulsion of the female retraction tension spring 736 stretched between a spring hook 731a provided on the other end side of the upper swing arm 731 and a spring hook 735 provided on the lower side of the female unit mounting plate 734. Since the spring hook 731a of the upper swing arm 731 is locked by the second spring hook locking part 734b of the female unit mounting plate 734 by the force, it is possible to prevent the knife drive part 710 from returning backward. As a result, the longitudinal direction of the long groove 702 of the driven portion 701 is oriented in the vertical direction, so that the pin 84 of the driving portion 751 of the clutch 75 only floats in the long groove 702 of the driven portion 701, and shuts off the power to the upper knife 72. Can be.
[0159]
In this manner, the knife edge of the cloth 5 is moved by the simple operation of the knob 715f of the knife unit base 715 for moving the knife drive section 710 from the vertical knife operating position to the horizontal knife retracting position by drawing an irregular elliptical trajectory. It is possible to smoothly switch to the work in which only the main sewing is performed without cutting the 5c.
[0160]
Thus, lockstitching can be performed.
[0161]
In addition, according to the preferred embodiment in which the stitch forming device of the sewing machine of the present invention is applied to a home-stitched overlock stitch sewing machine, a horizontal shuttle that performs a horizontal rotation motion is used. When the upper thread pierced through the needle rises from the bottom dead center of the needle, the upper thread and the lower thread cross each other, and a lock stitch portion including a stitch parallel to the surface of the body to be sewn and a vertical stitch. Any kettle may be used as long as it can be formed.
[0162]
In addition, the knife drive unit of the knife drive mechanism is not limited to the above-described one, and a lower lever is slidably mounted, and a positioning lever that fits the lower knife positioning locking portion into the positioning recess of the needle plate at the time of operating the knife is provided. Any structure may be used as long as it can be provided.
[0163]
Further, in the above-described embodiment, the upper looper thread 3 and the lower looper thread 4 intersect with all of the adjacent lockstitch portions 6, respectively. However, for example, as shown in FIG. The overhang portions 7 may cross each other. In this case, the ratio of the number of rotations of the lower shaft S2 and the looper drive unit 60 may be set such that the upper looper 30 and the lower looper 40 move by one cycle for one cycle of the two cycles of movement of the needle 10. .
[0164]
Further, in the above embodiment, the stitches 1a and 2a of the upper thread 1 and the lower thread 2 are respectively linear, but as shown in FIG. May be a folded line for each stitch.
[0165]
Further, the stitch forming apparatus of the sewing machine of the present invention can be applied not only to the home lock stitch overlock sewing machine as in the above embodiment but also to an industrial lock stitch overlock sewing machine.
[0166]
The industrial lock-stitch overlock sewing machine was placed on the needle plate by the upper thread pierced by the needle moving up and down in a direction perpendicular to the needle plate and the lower thread stored in the shuttle. When the upper thread pierced from the bottom dead center of the needle penetrating the needle which reciprocates in the vertical direction through the sewn body at every feed of the sewn body, the lower thread below the needle plate The upper thread and the lower thread are intersected by scooping with the blade point of the rotating and rotating kettle to form a final stitch portion composed of stitches parallel to the surface of the sewn body and stitches in the vertical direction. Make a reciprocating motion that draws a trajectory up and down, and draw a locus below the needle plate above the needle plate and a locus below the needle plate, and stimulate the lower looper that intersects with the needle trajectory and the upper looper respectively. The sewing machine includes a stitch forming device of a sewing machine that forms an overlock stitch portion with the upper looper thread and the lower looper thread passed through.
[0167]
A looper thread balance 400 as a looper thread supply means including an upper looper thread balance 401 and a lower looper thread balance 402 as shown in FIGS. 4, 5, and 6 is provided in the stitch forming apparatus of the sewing machine. Thus, the upper looper thread 3 and the lower looper thread 4 previously stored by the looper thread balance 400 can be tightened when the needle is pierced through the sewing body. As shown in FIGS. 4, 5, and 6, the upper looper thread balance 401 includes a looper balance drive arm 404 and a cam driver 405, and the lower looper thread balance 402 is provided at one end of the looper balance drive arm 404. Thus, the upper looper thread balance 401 and the lower looper thread balance 402 can be driven and controlled only by the cam driver 405 that is driven by the looper drive unit 60 at a variable speed.
[0168]
4, 5, and 6, a crank 61a, an L-shaped looper drive link 62, an upper looper mounting arm 63, a lower looper drive link 64, and a lower looper mounting arm 65 as shown in FIGS. Is provided. Thus, when the crank 61a of the looper drive unit 60 performs a rotational movement, the L-shaped looper drive link 62 connected to the crank 61a is driven, so that the L-shaped looper drive link 62 is connected to the long link end 62a. The upper looper mounting arm 63 converts the rotational motion of the looper drive shaft 61 into a swinging motion of the upper looper 30, while the short link end 62 b of the L-shaped looper drive link 62 is connected to the crank mounted on the looper drive shaft 61. 61a, the upper looper mounting arm 63 and the long link of the L-shaped looper drive link 62 are restrained by a four-bar rotating chain to generate a non-uniform elliptical motion. Therefore, they are connected via a lower looper drive link 64. The lower looper mounting arm 65 converts the rotational motion of the looper drive shaft 61 into a non-uniform swinging motion of the lower looper 40. Therefore, when the looper driving section 60 is driven and the tip of the upper looper 30 and the tip of the lower looper 40 cross each other, it is possible to prevent collision.
[0169]
In addition, the stitch forming apparatus of the sewing machine includes a looper threading device 300 having a threading air pump 304 as shown in FIGS. At this time, in the industrial lock stitch overlock sewing machine, since the overlock stitch is always performed, the upper looper mounting arm shaft 600 and the lower looper mounting arm shaft 69 of the looper driving unit 60 have a hollow structure in FIG. The upper looper 30 and the lower looper 40 are provided with the looper thread inlets, so that the looper threading device 300 can control the thread guide outlets 305b of the hollow thread guides 305 and 306 for the upper looper 30 and the lower looper 40, respectively. The looper thread entrances of the upper looper 30 and the lower looper 40 can always be aligned with 306b. In this state, the threading air pump 304 directs the hollow thread guides 305, 306 from the inlets of the hollow thread guides 305b, 306b, the looper thread inlets of the upper looper 30, the lower looper 40, and the looper blade point thread outlets 30b, 40b. The upper looper thread 3 and the lower looper thread 4 can be fed out, and processing, assembly, and the like for matching the looper thread inlets of the upper looper 30 and the lower looper 40 and the thread guide outlets 305b and 306b of the thread guides 305 and 306 can be performed. Adjustment becomes easy.
[0170]
The scalpel drive mechanism 70 shown in FIGS. 1, 3, 11, and 14 draws a trajectory in the vertical direction with respect to the needle plate and penetrates a needle that moves up and down, and a lower thread stored in a shuttle. When the needle thread penetrating the needle which reciprocates vertically in the vertical direction through the sewing object at every feed of the sewing object placed on the needle plate by the thread and rises from the bottom dead center of the needle, Under the needle plate, the lower thread is stored, and the upper thread and the lower thread intersect by scooping with the blade point of the rotating kettle to cross the upper thread and the lower thread from the seam parallel to the surface of the body to be sewn and the vertical seam. The present invention can also be applied to a household lockstitch sewing machine provided with a stitch forming device for a lockstitch that performs lockstitch such as straight stitching and zigzag stitching. As a result, the knife cutting mechanism can be incorporated into the existing structure space of the sewing machine in a compact manner, without cutting the cloth edge and performing the overlock sewing with the lockstitch without cutting the cloth edge. The operation for performing the main sewing can be easily switched and executed.
[0171]
【The invention's effect】
As described above, according to the stitch forming apparatus for a sewing machine of the present invention, the sewing machine has both functions of a lock stitch and an overlock stitch, and can be formed at once by one sewing machine. A knife cutting mechanism can be incorporated into the existing structural space, and it can be executed by switching between the work of cutting the cloth edge and performing the overlock sewing with the lockstitch and the work of performing the lockstitch without cutting the cloth edge, Furthermore, threading can be easily performed.
[Brief description of the drawings]
FIG. 1 is an overall perspective view showing a preferred embodiment of a sewing stitch forming apparatus of the present invention applied to a lock stitch overlock sewing machine.
FIGS. 2A and 2B are explanatory views briefly showing the operation of a lockstitch overlock sewing machine to which the stitch forming apparatus of the sewing machine of the present invention is applied.
FIG. 3 is a block diagram showing a drive system of a lockstitch overlock sewing machine to which the stitch forming apparatus of the present invention is applied.
FIG. 4 is an exploded perspective view showing a looper drive unit in the stitch forming apparatus of the sewing machine of the present invention.
FIGS. 5A and 5B are explanatory diagrams showing an operation state of a looper drive unit in the stitch forming apparatus of the sewing machine of the present invention, wherein FIG. 5A is a diagram when the upper looper is at a top dead center, and FIG. Figure at the time of the point.
FIGS. 6A and 6B are explanatory diagrams showing an operation state of a looper driving unit in the stitch forming apparatus of the sewing machine according to the present invention, wherein FIG. 6A is a diagram when the lower looper is at the most protruding point, and FIG. Figure at the time of the point.
FIG. 7 is a movement mechanism diagram showing an operation state of a looper drive unit in the sewing machine stitch forming apparatus of the present invention.
FIG. 8 is an exploded perspective view showing a looper clutch and a lockstitch / overlock switchover control unit in the stitch forming apparatus of the sewing machine of the present invention.
9A and 9B are diagrams illustrating an operation state of a looper clutch and a lockstitch / overlocking changeover control unit in the stitch forming apparatus of the sewing machine according to the present invention, wherein FIG. FIG.
FIGS. 10A and 10B are explanatory diagrams showing an operation state of a looper clutch in the stitch forming apparatus of the sewing machine of the present invention, wherein FIG. 10A is a diagram showing a state where power is transmitted from a lower shaft to a looper drive shaft, and FIG. FIG. 4 is a diagram illustrating a state in which power from the shaft to the looper drive shaft is shut off.
FIG. 11 is a perspective view showing a knife driving mechanism in the stitch forming apparatus of the sewing machine of the present invention.
FIGS. 12A and 12B are explanatory views showing an operation state of a motion conversion mechanism in a knife drive mechanism of the stitch forming device of the sewing machine of the present invention.
FIG. 13 is an explanatory view showing the operation of the motion conversion mechanism in the knife drive mechanism of the stitch forming device of the sewing machine of the present invention.
FIG. 14 is an exploded perspective view showing a knife drive unit and a four-bar rotary link in the knife drive mechanism of the stitch forming apparatus of the sewing machine of the present invention.
FIG. 15 is a perspective view showing a looper threading device in the stitch forming device of the sewing machine of the present invention.
FIG. 16 is an exploded perspective view showing a looper threading device in the stitch forming device of the sewing machine of the present invention.
FIG. 17 is a detailed view showing a relationship between a thread introduction member and a connection switching member of the looper threading device in the stitch forming device of the sewing machine of the present invention.
FIGS. 18 (a) and (b) are explanatory views showing a thread introduction member of a looper threading device in the stitch forming apparatus of the sewing machine of the present invention.
FIG. 19 is an exploded perspective view showing a thread introduction member and a connection switching member of the looper threading device in the stitch forming device of the sewing machine of the present invention.
FIGS. 20A and 20B are explanatory views showing a hatch opening / closing section in the stitch forming apparatus of the sewing machine of the present invention, wherein FIG. 20A is a view showing a hatch opening state, and FIG. 20B is a view showing a hatch closing state.
FIG. 21 is a perspective view showing an operating state of a four-joint rotary link of a knife drive mechanism in the stitch forming apparatus of the sewing machine of the present invention.
FIG. 22 is a perspective view showing an operating state of a four-joint rotary link of a scalpel drive unit in the stitch forming apparatus of the sewing machine of the present invention.
FIG. 23 is a perspective view showing an operating state of a four-joint rotary link of a scalpel drive unit in the stitch forming apparatus of the sewing machine of the present invention.
FIG. 24 is a perspective view showing an operating state of a four-bar rotary link of the knife drive mechanism in the stitch forming apparatus of the sewing machine of the present invention.
FIGS. 25A and 25B are explanatory diagrams showing a knife driving unit in the stitch forming apparatus of the sewing machine of the present invention, wherein FIG. 25A is a diagram showing a knife non-operation state, and FIG.
FIG. 26 is a diagram illustrating an operation state of a looper driving unit in the stitch forming apparatus of the sewing machine according to the present invention, in which (a) is an explanatory diagram illustrating a relationship between an upper looper and a lower looper when the upper looper is raised; (b) is an explanatory diagram showing the relationship between the upper looper and the lower looper when the upper looper is descending.
FIG. 27 is a view showing a stitch formed by a lock stitch overlock sewing machine to which the sewing machine stitch forming apparatus of the present invention is applied, and FIG. 27 (a) is a stitch in which a lock stitch portion crosses every stitch of a lock stitch portion. (B) is an explanatory view of a stitch in which the overlock portion crosses every other or every two stitch portions, and (c) is a zigzag shape of the stitch portion for each stitch, or Explanatory drawing of the stitch which becomes a folding line shape for every several stitches.
FIG. 28 is a perspective view showing the configuration of a lockstitch overlock attachment used by being attached to a lockstitch sewing machine.
[Explanation of symbols]
1 ... Upper thread
2 ... Bottom thread
3 ... Upper looper thread
4 Lower looper thread
6 Lock stitch section
7 ... Overhanging part
8 ... needle plate
10 ... needle
16 ... Needle balance
20 ... pot
21 ... Sword point
30 Upper looper
30a ・ ・ ・ ・ ・ ・ looper thread entrance
30b ... Looper pointed thread outlet
35 ... Upper looper thread tensioner
40 ... Lower looper
40a: Looper thread entrance
40b ... Looper pointed thread outlet
45 Lower looper thread tensioner
60 Looper drive unit
61 ... Looper drive shaft
61a: Looper drive shaft
62 L-shaped looper drive link
62a ... Long link end
62b ... short link end
63 Upper arm attachment arm
64 Lower link drive link
65 Lower arm mounting arm
71 ... Motion conversion mechanism
72 Upper knife
73 ・ ・ ・ ・ ・ ・ Lower knife
75 ... female clutch
110 Needle drop control unit
130 seam selection device
300 Looper threading device
304 Threading air pump
305... Upper looper yarn conduit (hollow yarn guide)
305b ・ ・ ・ ・ ・ ・ Thread guide outlet
306... Lower looper yarn conduit (hollow yarn guide)
306b ・ ・ ・ ・ ・ ・ Thread guide outlet
400 Looper thread balance (looper thread supply means)
401 Upper looper thread balance
402: Lower looper thread balance
403... Variable speed drive cam mechanism
404 ... looper balance driving arm
405 ... Cam drive
500 ... looper clutch
510 ・ ・ ・ ・ ・ ・ Lock stitch / overlock switching control unit
601 hatch
602: Hatch opening / closing part
603: Cloth waste guide plate
604 ... Hatch open / close spring
710... Scalpel drive unit
730: Four-link rotary link
FR ... machine frame
S1 · · · · · · Upper shaft (rotary shaft)
L10: The trajectory of the needle
L30: Arc path of upper looper
L40: Arc locus of lower looper

Claims (21)

The upper thread penetrated by a needle moving up and down in a vertical direction with respect to the needle plate, and the lower thread stored in the shuttle, the feed thread to be sewn on the needle plate every one feed is moved. When the upper thread penetrating the needle which reciprocates in the vertical direction through the sewn body and rises from the bottom dead center of the needle, the lower thread is stored below the needle plate and the lower thread is stored and rotated. The upper thread and the lower thread intersect with each other by scooping with a blade point of a shuttle to form a main stitch portion such as a straight stitch, a zigzag stitch, or the like, which includes a stitch parallel to a surface of the sewn body and a vertical stitch. A reciprocating motion that draws a locus above and below the needle plate, an upper looper that intersects the locus of the needle above the needle plate, a locus that draws a locus below the needle plate, the locus of the needle and the upper looper Overlock sewing with upper looper thread and lower looper thread pierced through the lower looper that intersects with the locus of Stitch formation of the sewing machine that controls the needle dropping of the needle and the cloth feed control of the sewn object according to the stitch selection of the stitch selection device that switches to the sewing mode of the lockstitch or the overlock stitch. A device,
A lockstitch / edge-overlock switching control unit that controls switching between the lockstitch and the edge-overlock stitch in conjunction with the stitch selection of the seam selection device; and the lock-stitch / edge-overlock switch control unit provided on the needle plate. A hatch that is opened when the upper looper is moved up and down the needle plate in conjunction with the switching control to the overlock stitch, and a switching control to the lockstitch by the lockstitch / overlock overswitching control unit. A stitch forming apparatus for a sewing machine, comprising: a looper threading device for threading the upper looper thread and the lower looper thread through the upper looper and the lower looper, respectively. 2. The stitch forming apparatus for a sewing machine according to claim 1, further comprising a needle drop control unit that controls the needle drop of the needle in conjunction with the switching control of the lockstitch / overlock switching control unit. 2. The stitch forming apparatus for a sewing machine according to claim 1, further comprising a cloth feeder that controls the cloth feed of the sewn object in conjunction with stitch selection by the stitch selector. The upper looper is opened when the upper looper moves up and down the needle plate in conjunction with the switching control to the overlock stitching of the lockstitch / overlock switching control unit, and the lock stitching / overlock switching control unit of the 2. The sewing machine according to claim 1, further comprising a hatch opening / closing portion that opens and closes the hatch so as to close the upper looper when the upper looper is retracted to a fixed position in conjunction with the switching control to the lockstitch. Seam forming device. The power is transmitted to the upper looper and the lower looper in conjunction with the switching control to the overlock stitching of the lockstitch / overlock stitching switching control unit to form the lockstitch portion and the edge overlock stitch portion, and the lockstitch. A looper clutch that forms the lockstitch by shutting off the power when the upper looper is retracted to a fixed position in conjunction with the overlock switch control unit switching control to the lockstitch. The stitch forming apparatus for a sewing machine according to claim 1, wherein The upper thread penetrated by a needle moving up and down in a vertical direction with respect to the needle plate, and the lower thread stored in the shuttle, the feed thread to be sewn on the needle plate every one feed is moved. When the upper thread penetrating the needle which reciprocates in the vertical direction through the sewn body and rises from the bottom dead center of the needle, the lower thread is stored below the needle plate and the lower thread is stored and rotated. The upper thread and the lower thread intersect with each other by scooping with a blade point of a shuttle to form a main stitch portion such as a straight stitch, a zigzag stitch, or the like, which includes a stitch parallel to a surface of the sewn body and a vertical stitch. A reciprocating motion that draws a locus above and below the needle plate, an upper looper that intersects the locus of the needle above the needle plate, a locus that draws a locus below the needle plate, the locus of the needle and the upper looper Overlock sewing with upper looper thread and lower looper thread pierced through the lower looper that intersects with the locus of Stitch formation of the sewing machine that controls the needle dropping of the needle and the cloth feed control of the sewn object according to the stitch selection of the stitch selection device that switches to the sewing mode of the lockstitch or the overlock stitch. A device,
Interlocking with the switching control to the overlock stitching of the lockstitch / overlock stitching switching control unit, power is transmitted to the upper looper and the lower looper to form the lockstitch portion and the edge overlock stitching portion, and the lockstitch. A looper clutch for forming the lockstitch by cutting off the power when the upper looper is retracted to a fixed position in interlocking with the overlocking switching control unit switching control to the lockstitch; and the looper clutch is engaged. A crank which is mounted on a looper drive shaft which is driven when it is driven, performs a rotary motion, an L-shaped looper drive link connected to the crank, a long end of the L-shaped looper drive link which is supported by the machine frame at an intermediate portion and has one end. An upper looper mounting arm that is connected to the upper looper and that swings with the rotational movement of the crank, and that is connected to the short link end of the L-shaped looper drive link and is unequal with the rotational movement of the crank. Speed A lower looper drive link that moves in a circular motion, and a looper drive unit that includes a lower looper mounting arm that supports the lower looper with one end pivotally supported by the machine frame at an intermediate portion and having one end connected to the lower looper drive link. A stitch forming apparatus for a sewing machine. The upper thread penetrated by a needle moving up and down in a vertical direction with respect to the needle plate, and the lower thread stored in the shuttle, the feed thread to be sewn on the needle plate every one feed is moved. When the upper thread penetrating the needle which reciprocates in the vertical direction through the sewn body and rises from the bottom dead center of the needle, the lower thread is stored below the needle plate and the lower thread is stored and rotated. The upper thread and the lower thread intersect with each other by scooping with a blade point of a shuttle to form a main stitch portion such as a straight stitch, a zigzag stitch, or the like, which includes a stitch parallel to a surface of the sewn body and a vertical stitch. A reciprocating motion that draws a locus above and below the needle plate, an upper looper that intersects the locus of the needle above the needle plate, a locus that draws a locus below the needle plate, the locus of the needle and the upper looper Overlock sewing with upper looper thread and lower looper thread pierced through the lower looper that intersects with the locus of Stitch formation of the sewing machine that controls the needle dropping of the needle and the cloth feed control of the sewn object according to the stitch selection of the stitch selection device that switches to the sewing mode of the lockstitch or the overlock stitch. A device,
The upper looper thread and the lower looper thread are looped around the needle in conjunction with the movement trajectory of the upper looper and the lower looper in accordance with the switching control to the overlock stitching by the lockstitch / overlock stitching switching control unit. The upper looper thread and the lower looper thread required for the overlock stitching are rewound through a thread tensioner and stored, and the needle comes off from the upper looper thread and the lower looper thread. And a looper thread supply means for supplying the upper looper thread and the lower looper thread which have been wound and stored after the upper thread has been tightened by the upper thread balance to the upper looper and the lower looper. Sewing machine of the sewing machine. The upper thread penetrated by a needle that moves up and down in a vertical direction with respect to the needle plate and the lower thread stored in the shuttle have the thread to be sewn on the needle plate at every feed of the sewing object placed on the needle plate. When the upper thread pierced through the needle that reciprocates vertically in the sewing body through the sewn body and rises from the bottom dead center of the needle, the lower thread is located below the needle plate, and the lower thread is stored and rotated. The upper thread and the lower thread intersect with each other by scooping with a blade point of a shuttle to form a final stitch portion composed of stitches parallel to the surface of the sewn body and stitches in the vertical direction. The upper looper crosses the trajectory of the needle above the needle plate, and the lower loop crosses the trajectory of the needle below the needle plate. Sewing of a sewing machine that forms overlock stitches with the upper looper thread and lower looper thread that have been passed through the looper, respectively. A forming apparatus,
The upper looper thread and the lower looper thread necessary for the overcasting when the upper looper thread and the lower looper thread are looped around the needle in conjunction with the motion trajectories of the upper looper and the lower looper. After the needle is pulled out of the upper looper thread and the lower looper thread and the upper thread is thread-tightened by the upper thread balance, the thread is threaded and stored. A stitch forming device for a sewing machine, comprising: a looper thread supply means for supplying the selected upper looper thread and lower looper thread to the upper looper and the lower looper. The upper thread penetrated by a needle moving up and down in a vertical direction with respect to the needle plate, and the lower thread stored in the shuttle, the feed thread to be sewn on the needle plate every one feed is moved. When the upper thread penetrating the needle which reciprocates in the vertical direction through the sewn body and rises from the bottom dead center of the needle, the lower thread is stored below the needle plate and the lower thread is stored and rotated. The upper thread and the lower thread intersect with each other by scooping with a blade point of a shuttle to form a main stitch portion such as a straight stitch, a zigzag stitch, or the like, which includes a stitch parallel to a surface of the sewn body and a vertical stitch. A reciprocating motion that draws a locus above and below the needle plate, an upper looper that intersects the locus of the needle above the needle plate, a locus that draws a locus below the needle plate, the locus of the needle and the upper looper Overlock sewing with upper looper thread and lower looper thread pierced through the lower looper that intersects with the locus of Stitch formation of the sewing machine that controls the needle dropping of the needle and the cloth feed control of the sewn object according to the stitch selection of the stitch selection device that switches to the sewing mode of the lockstitch or the overlock stitch. A device,
The upper looper and the lower looper have a hollow structure from a looper thread entrance to a looper blade tip thread exit,
The upper looper, the upper looper thread guided to the lower looper, and the upper looper interlocked with the lock control of the lock stitch / overlock switch control unit from the thread inlet for inserting the lower looper thread to the lock stitch. A hollow thread for threading the upper looper thread and the lower looper thread to a thread guide outlet corresponding to the looper thread entrance of the upper looper and the lower looper when retracted to a fixed position below the needle plate, respectively; A looper threading device having a guide, the upper looper thread and the lower looper thread being passed from the inlet of the thread guide to the upper looper and the lower looper thread while the looper thread entrance of the lower looper is aligned with the thread guide outlet. A stitch forming apparatus for a sewing machine, comprising: a thread guide outlet of a thread guide; an upper looper; a looper thread inlet of the lower looper; and a threading air pump fed from a looper tip end thread outlet. The power is transmitted to the upper looper and the lower looper in conjunction with the switching control to the overlock stitching of the lockstitch / overlock stitching switching control unit to form the lockstitch portion and the edge overlock stitch portion, and the lockstitch. Interlocking with the switching control to the lock stitching by the overlock switch control unit, cuts off the power to form the lock stitch portion, and when the power is cut off, retracts the upper looper to the fixed position to thereby guide the thread. The stitch forming apparatus for a sewing machine according to claim 9, further comprising a looper clutch that matches an outlet with the looper thread entrance. The upper thread penetrated by a needle moving up and down in a vertical direction with respect to the needle plate, and the lower thread stored in the shuttle, the feed thread to be sewn on the needle plate every one feed is moved. When the upper thread penetrating the needle which reciprocates in the vertical direction through the sewn body and rises from the bottom dead center of the needle, the lower thread is stored below the needle plate and the lower thread is stored and rotated. The upper thread and the lower thread intersect with each other by scooping with a blade point of a shuttle to form a main stitch portion such as a straight stitch, a zigzag stitch, or the like, which includes a stitch parallel to a surface of the sewn body and a vertical stitch. A reciprocating motion that draws a locus above and below the needle plate, an upper looper that intersects the locus of the needle above the needle plate, a locus that draws a locus below the needle plate, the locus of the needle and the upper looper Overlock sewing with upper looper thread and lower looper thread pierced through the lower looper that intersects with the locus of Stitch formation of the sewing machine that controls the needle dropping of the needle and the cloth feed control of the sewn object according to the stitch selection of the stitch selection device that switches to the sewing mode of the lockstitch or the overlock stitch. A device,
The upper looper and the lower looper have a hollow structure from a looper thread entrance to a looper blade tip thread exit,
The upper looper, the upper looper thread guided to the lower looper, and the upper looper interlocked with a changeover control to the lockstitch by the lockstitch / edge-overlock switchover control unit from a thread inlet for inserting the lower looper thread. A hollow thread for threading the upper looper thread and the lower looper thread to a thread guide outlet corresponding to the looper thread entrance of the upper looper and the lower looper when retracted to a fixed position below the needle plate, respectively. Equipped with a looper threading device having a guide,
The upper looper, the looper thread inlet of the lower looper, and the thread guide outlet of the thread guide are arranged in a direction crossing a motion plane drawn by the upper looper and the lower looper,
The upper looper thread and the lower looper thread are fed from the introduction port of the thread guide to the thread guide outlet of the thread guide in a state where the looper thread entrance of the upper looper and the lower looper match the thread guide exit. A stitch forming apparatus for a sewing machine, comprising: a looper, a threading air pump that feeds the looper thread inlet of the lower looper, and a looper blade tip thread outlet. Power is transmitted to the upper looper and the lower looper in conjunction with the switching control to the overlock stitching of the lockstitch / overlock switchover control unit to form the overlock stitch portion, and the lockstitch / overlock switchover is performed. The power is cut off in conjunction with the switching control to the lock stitch by the control unit to form the lock stitch portion, and when the power is cut off, the upper looper is retracted to the fixed position and the thread guide outlet is moved to the looper. The stitch forming apparatus for a sewing machine according to claim 11, further comprising a looper clutch that matches a thread entrance. The upper thread penetrated by a needle that moves up and down in a vertical direction with respect to the needle plate and the lower thread stored in the shuttle have the thread to be sewn on the needle plate at every feed of the sewing object placed on the needle plate. When the upper thread pierced through the needle that reciprocates vertically in the sewing body through the sewn body and rises from the bottom dead center of the needle, the lower thread is located below the needle plate, and the lower thread is stored and rotated. The upper thread and the lower thread intersect with each other by scooping with a blade point of a shuttle to form a final stitch portion composed of stitches parallel to the surface of the sewn body and stitches in the vertical direction. The upper looper crosses the trajectory of the needle above the needle plate, and the lower loop crosses the trajectory of the needle below the needle plate. Sewing of a sewing machine that forms overlock stitches with the upper looper thread and lower looper thread that have been passed through the looper, respectively. A forming apparatus,
The upper looper and the lower looper have a hollow structure from a looper thread entrance to a looper blade tip thread exit,
The upper looper, the upper looper thread guided to the lower looper, the upper looper thread from the thread inlet for inserting the lower looper thread to the upper looper, the thread guide outlet that matches the looper thread inlet of the lower looper, A looper threading device having a hollow thread guide for threading the lower looper thread is provided,
The upper looper, the looper thread inlet of the lower looper, and the thread guide outlet of the thread guide are arranged in a direction crossing a motion plane drawn by the upper looper and the lower looper,
The upper looper thread and the lower looper thread are fed from the introduction port of the thread guide to the thread guide outlet of the thread guide in a state where the looper thread entrance of the upper looper and the lower looper match the thread guide exit. A stitch forming apparatus for a sewing machine, comprising: a looper, a threading air pump that feeds the looper thread inlet of the lower looper, and a looper blade tip thread outlet. The upper thread penetrated by a needle moving up and down in a vertical direction with respect to the needle plate, and the lower thread stored in the shuttle, the feed thread to be sewn on the needle plate every one feed is moved. When the upper thread penetrating the needle which reciprocates in the vertical direction through the sewn body and rises from the bottom dead center of the needle, the lower thread is stored below the needle plate and the lower thread is stored and rotated. The upper thread and the lower thread intersect with each other by scooping with a blade point of a shuttle to form a main stitch portion such as a straight stitch, a zigzag stitch, or the like, which includes a stitch parallel to a surface of the sewn body and a vertical stitch. A reciprocating motion that draws a locus above and below the needle plate, an upper looper that intersects the locus of the needle above the needle plate, a locus that draws a locus below the needle plate, the locus of the needle and the upper looper Overlock sewing with upper looper thread and lower looper thread pierced through the lower looper that intersects with the locus of Stitch formation of the sewing machine that controls the needle dropping of the needle and the cloth feed control of the sewn object according to the stitch selection of the stitch selection device that switches to the sewing mode of the lockstitch or the overlock stitch. A device,
A hatch provided on the needle plate and openable and closable in response to switching control of the lockstitch / overlock switchover control unit, and linked to switching control to the overlock stitch by the lockstitch / overlock switchover control unit. The upper looper is opened when the upper looper moves up and down the needle plate, and when the upper looper is retracted to a fixed position in conjunction with switching control to the lockstitch by the lockstitch / edge-overlock switching control unit. A hatch opening / closing section for driving the hatch to open and close so as to close the stitch. In the hatch, the cloth waste cut off at the time of the edge overlock sewing of the upper looper thread pierced through the upper looper that moves up and down in the opening formed when the hatch is opened is guided to the right outward when viewed in the sewing direction. 15. The cloth waste guide plate constituting the same surface as the needle plate together with the hatch when the hatch is closed is prevented from falling into the opening, and the hatch is closed when the hatch is closed. Sewing machine for sewing machine. The upper thread penetrated by a needle moving up and down in a vertical direction with respect to the needle plate, and the lower thread stored in the shuttle, the feed thread to be sewn on the needle plate every one feed is moved. When the upper thread penetrating the needle which reciprocates in the vertical direction through the sewn body and rises from the bottom dead center of the needle, the lower thread is stored below the needle plate and the lower thread is stored and rotated. The upper thread and the lower thread intersect with each other by scooping with a blade point of a shuttle to form a main stitch portion such as a straight stitch, a zigzag stitch, or the like, which includes a stitch parallel to a surface of the sewn body and a vertical stitch. A reciprocating motion that draws a locus above and below the needle plate, an upper looper that intersects the locus of the needle above the needle plate, a locus that draws a locus below the needle plate, the locus of the needle and the upper looper Overlock sewing with upper looper thread and lower looper thread pierced through the lower looper that intersects with the locus of Stitch formation of the sewing machine that controls the needle dropping of the needle and the cloth feed control of the sewn object according to the stitch selection of the stitch selection device that switches to the sewing mode of the lockstitch or the overlock stitch. A device,
An upper knife moving up and down via a motion conversion mechanism interlocked with a rotation shaft for driving the needle, and a lower knife cooperating with the upper knife so as to slidably guide the upper knife so that a cloth edge of the sewing object is formed. The knife drive section that cuts off the irregular elliptical trajectory between the operating position on the needle plate when the knife is operated and the retracted position at the lower part of the arm of the sewing machine when the knife is not operated by the four-bar rotating link having a different internode length. I pivoted to the machine frame to draw and change,
The movement conversion mechanism is configured such that the knife drive unit transmits vertical movement to the upper knife at the operating position, and transmits the vertical movement to the upper knife at the retracted position. A stitch forming device for a sewing machine, wherein the stitch forming device is connected. The upper thread penetrated by a needle that moves up and down in a vertical direction with respect to the needle plate and the lower thread stored in the shuttle have the thread to be sewn on the needle plate at every feed of the sewing object placed on the needle plate. When the upper thread pierced through the needle that reciprocates vertically in the sewing body through the sewn body and rises from the bottom dead center of the needle, the lower thread is located below the needle plate, and the lower thread is stored and rotated. The upper thread and the lower thread are intersected by scooping with a blade point of a shuttle hook, and main sewing such as straight stitching, zigzag stitching, and the like, which are made up of stitches parallel to the surface of the sewn body and stitches in the vertical direction, are performed. A stitch forming device for a sewing machine,
An upper knife moving up and down via a motion conversion mechanism interlocked with a rotation shaft for driving the needle, and a lower knife cooperating with the upper knife so as to slidably guide the upper knife so that a cloth edge of the sewing object is formed. The knife drive section that cuts off the irregular elliptical trajectory between the operating position on the needle plate when the knife is operated and the retracted position at the lower part of the arm of the sewing machine when the knife is not operated by the four-bar rotating link having a different internode length. I pivoted to the machine frame to draw and change,
The movement conversion mechanism is configured such that the knife drive unit transmits vertical movement to the upper knife at the operating position, and transmits the vertical movement to the upper knife at the retracted position. A stitch forming device for a sewing machine, wherein the stitch forming device is connected. The upper thread penetrated by a needle moving up and down in a vertical direction with respect to the needle plate, and the lower thread stored in the shuttle, the feed thread to be sewn on the needle plate every one feed is moved. When the upper thread penetrating the needle which reciprocates in the vertical direction through the sewn body and rises from the bottom dead center of the needle, the lower thread is stored below the needle plate and the lower thread is stored and rotated. The upper thread and the lower thread intersect with each other by scooping with a blade point of a shuttle to form a main stitch portion such as a straight stitch, a zigzag stitch, or the like, which includes a stitch parallel to a surface of the sewn body and a vertical stitch. A reciprocating motion that draws a locus above and below the needle plate, an upper looper that intersects the locus of the needle above the needle plate, a locus that draws a locus below the needle plate, the locus of the needle and the upper looper Overlock sewing with upper looper thread and lower looper thread pierced through the lower looper that intersects with the locus of A stitch forming apparatus of a sewing machine for forming a
A looper clutch that transmits power to the upper looper and the lower looper to form the edge overlock portion, and shuts off the power when the upper looper is retracted to a fixed position to form the lockstitch portion; A crank that is mounted on a looper drive shaft that is driven when the clutch is engaged and performs a rotary motion; an L-shaped looper drive link connected to the crank; An upper looper mounting arm that is connected to a long link end and carries the upper looper and swings with the rotational movement of the crank; an upper looper mounting arm that is connected to a short link end of the L-shaped looper drive link and associated with the rotational movement of the crank; A lower looper drive link that moves unequally in an elliptical manner, and a lower looper mounting arm that supports the lower looper by being supported at the intermediate portion by the machine frame and having one end connected to the lower looper drive link. Stitch forming apparatus of the sewing machine, characterized in that a looper drive portion that. When the upper looper descends and the looper thread inlet passes through the thread guide outlet, the upper looper thread is entangled with the needle to start tightening of the upper looper thread, and the upper looper further descends to lower the upper looper thread. After the thread has been tightened, the upper looper reaches the bottom dead center and before the needle comes out of the sewing body, the upper looper thread is threaded in through a thread tensioner to accumulate the thread, and the upper looper is driven. When the ascent starts, the accumulated upper looper thread is released, and when the upper looper ascends and starts to descend after passing through the upper looper top dead center, the needle scoops the upper looper thread while descending from the top dead center. An upper looper thread balance that performs threading so as to apply tension to the upper looper thread at a point in time, and the lower looper thread is entangled with the needle when the lower looper is retracted and the looper thread inlet passes through the thread guide outlet. To open the lower looper thread. The lower looper is further retracted, and after the lower looper thread is completely tightened, the lower looper thread is fed through the thread tensioner until the lower looper reaches the final retreat point, and the lower looper thread is accumulated. 14. The stitch forming apparatus for a sewing machine according to claim 11, further comprising a lower looper thread balance for discharging the accumulated thread when the looper moves forward. The upper looper thread balance is provided with a looper balance driving arm pivotally attached to a machine frame and having a speed-change driving cam groove, and a cam that slides in the speed-change driving cam groove to shift-drive the looper balance driving arm by a looper driving unit. And a driver
20. The stitch forming apparatus for a sewing machine according to claim 19, wherein the lower looper thread balance is provided at one end of the looper balance driving arm. The hatch opening / closing section is opened when the upper looper moves up and down the needle plate in conjunction with switching control to the overlock stitching of the lockstitch / overlock stitching switching control section. When the upper looper retreats to a fixed position in conjunction with the overlock switching control section switching control to the lockstitch, the looper clutch is completely disengaged, the power to the upper looper is shut off, and the hatch is closed. 15. The stitch forming apparatus for a sewing machine according to claim 4, wherein a hatch opening / closing spring for performing the operation is provided so as to interlock with the lockstitch / overlock switching control section.

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