JP2002102574A - Looper drive mechanism for sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a looper drive mechanism having both functions of a lock stitch and an over-edge chain stitch and capable of forming a lock stitch section and an over-edge chain stitch section in one sewing with one sewing machine. SOLUTION: The lock stitch section comprising parallel seams and vertical seams is formed on the face of a sewn body 5 by a needle thread piercing a needle 10 and a bobbin thread stored in a shuttle 20, and the over-edge chain stitch section is formed by an upper looper thread and a lower looper thread piercing an upper looper 30 and a lower looper 40 respectively in a looper drive mechanism. The upper looper 30 and the lower looper 40 are provided below a throat plate 8, respectively, and bayonet points 31 and 41 are arranged in the same direction to pass through a side face on this side of the needle in the sewing direction. A looper drive section 60 driving the upper looper 30 and the lower looper 40 is provided so that the loci L30 and L40 respectively of the upper looper 30 and the lower looper 40 move on the practically parallel planes to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a looper drive mechanism for a sewing machine, and more particularly to a looper drive mechanism for a sewing machine that can integrate a lockstitch and an overlock stitch.

[0002]

2. Description of the Related 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 vertical movement of the needle and scooping it with the blade point of the shuttle that stores the lower thread. Multiple fabrics can be seamed along the seams.

[0003] On the other hand, there is an overcast sewing to prevent fraying of an edge portion of a fabric or the like which is easily frayed. Depending on the number of threads for forming the seam and the number of needles that move substantially perpendicularly to the cloth surface, the overlock stitch has two needles and one overlock stitch (US Stitch type 503) or one stitch. Three-needle overlock stitching (US Stitch type 504), and two-needle five-thread stitching (US stitch type 516) known as an interlock that combines chain stitching and edge overlocking. is there.

However, in such an overlock sewing, for example, a needle thread is scooped from the side with two hook-shaped needles called a looper, and a needle is scooped by a looper thread moving horizontally to form a seam. Since the looper thread does not cross the needle thread in a direction perpendicular to the cloth surface, 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 (US Stitch type Stitch type 517) for performing the lock stitch together.

[0005]

SUMMARY OF THE INVENTION Such stitches (Stit)
The ch type 517) desirably has the lockstitch portion and the overlock portion as close as possible, but the lockstitch requires a shuttle portion for storing the lower thread below the needle that moves up and down. Since a looper that moves so as to cross the trajectory of the vertical movement of the needle, which is provided separately from the lockstitch, is required, both positions naturally have limitations. Accordingly, sewing machines for both lockstitching and overlock stitching have been proposed (JP-B-56-15268, JP-B-60-25145, JP-B-61-25396, etc.). This is a sewing machine that selects and uses a function, and it is impossible for the sewing machine to perform the lock stitch and the overlock stitch at once in a state of being close to each other.

[0006] On the other hand, attempts have been made to simultaneously perform lock stitching and edge overlock stitching (Japanese Patent Application Laid-Open Nos. 55-113490, 55-136085, 55-14).
No. 6190, JP-A-63-122495, etc.). 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 portion 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 vertical movement, which is provided separately from the lockstitch. Therefore, it is difficult for the sewing machine to perform the lock stitch and the overlock stitch at once in a state of being close to each other because both positions are limited.

There has also been proposed a lock stitch overlock attachment (trade name "Ruby Lock", manufactured by Toyo Seiki Kogyo Co., Ltd.) that performs lock stitch and overlock stitch all at once. This attachment is, as shown in FIG.
001 is used by being fixed to 001.
The drive arm 1003a of the crank 1003 pivotally supported by the attachment frame 1002 is driven by a needle bar (not shown) carrying the driven arm 1003, and the driven arm 1003b is pivotally supported by the attachment frame 1002 via the drive connection link 1004. Upper looper drive plate 1005
Rocks. The swing of the upper looper drive plate 1005 causes the upper looper 1007 pivotally supported by the attachment frame 1002 via the upper looper drive link 1006 to swing. On the other hand, the swing of the upper looper driving plate 1005 causes the pins 1005 protruding from the upper looper driving plate 1005 to protrude.
a slides in a groove 1008a provided in the lower looper driving plate 1008 pivotally supported by the attachment frame 1002, and swings the lower looper driving plate 1008. The swing of the lower looper drive plate 1008 causes the lower looper 1010 pivotally supported by the attachment frame 1002 to swing 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 when viewed in the cloth feeding direction. Must cross the needle 1011 at the lower surface of the cloth, so that it is inclined downward and to the left when viewed in the cloth feeding direction, and furthermore, the upper and lower loopers 1007 and 1010 intersect beside the cloth end. Are inclined to each other.

In FIG. 1, reference numeral 1014 denotes a needle 101.
A needle drop portion 1, a thread tensioner 1012, and a looper balance 1013 driven by a lower looper driving plate 1008.

In the attachment having the above-described structure, when the needle bar moves up and down, a needle thread (not shown) pierced through the needle 1011 and a bobbin thread (not shown) stored in a shuttle (not shown) (Not shown), 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, thereby driving the upper looper. The swing of the plate 1005 causes the upper looper drive link 10
06, the upper looper 1007 is swung, and the swing of the upper looper drive plate 1005 causes the upper looper drive plate 1005 to swing.
The pin 1005a protruding from the lower looper driving plate 100
8, the lower looper driving plate 1008 is oscillated, and the lower looper driving plate 1008 is oscillated to lower the lower looper 1010 via the lower looper driving link 1009. An overlock stitch is formed by an upper looper thread and a lower looper thread (not shown) pierced through the looper 1007 and the lower looper 1010, respectively.

However, in such an attachment, since the upper and lower loopers 1007 and 1010 are inclined, a high-level 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 households or by tailors, it is extremely troublesome to replace such an attachment with a work clamp and fix it to the work clamp bar. Upper looper 100 for the fixed needle
The operation of adjusting the positional relationship between the lower looper 7 and the lower looper 1010 is extremely complicated, and furthermore, it is necessary to cut the edge of the cloth to be overlocked with scissors in advance and then perform the overlocking operation. Have difficulties.

Therefore, the inventor of the present application has a single-needle, four-thread, lockstitch, overlock stitch structure having both functions of lockstitch and overlock stitch, and which can be formed at a time by a sewing machine, and a method of forming the same. (Japanese Patent No. 267209).
No. 7). 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 of forming the same.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and has both functions of a lockstitch and an overlock stitch, and can be formed at once by a single sewing machine. It is an object of the present invention to provide a looper driving mechanism.

[0013]

In order to achieve this object, a looper drive mechanism of a sewing machine according to the present invention is provided with a needle and a shuttle which penetrate a needle which moves up and down in a direction perpendicular to a needle plate. With the stored lower thread, 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 by the stored lower thread rises from the bottom dead center of the needle. At the time, the lower thread is stored under the needle plate, and the lower thread is stored in the rotatable shuttle and the upper thread and the lower thread are crossed to intersect with the stitch parallel to the surface of the body to be sewn. A seam is formed, and a reciprocating motion that draws a substantially circular locus above and below the needle plate, and an upper looper that intersects the needle locus above the needle plate and a lower looper below the needle plate. Draw a substantially arc-shaped trajectory, and pass through the lower looper that intersects with the trajectory of the needle and the trajectory of the upper looper, respectively. In a looper drive mechanism of a sewing machine in which an over loop portion is formed by an upper looper thread and a lower looper thread, the upper looper and the lower looper are provided below the needle plate, respectively, and each sword point is located on the near side of the needle when viewed from the sewing direction. A needle which is arranged in the same direction so as to pass through the side surface, and drives the upper looper and the lower looper so that their trajectories move on planes substantially parallel to each other; The upper looper thread pierced through the upper looper that reciprocates in a reciprocating motion by drawing an arc-shaped trajectory that crosses the trajectory above the needle plate and passes through the needle plate, descends from the top dead center when the upper looper descends from the top dead center The lower looper thread pierced through the lower looper that reciprocates by drawing a locus intersecting with the locus of the needle and the locus of the upper looper below the needle plate. When moving to the bottom of the needle plate When the lower looper is scooped by the descending needle and the upper looper ascending from the lower dead center when the lower looper moves to the other end, the upper looper thread and the lower looper thread intersect at the edge of the sewn body. A looper drive unit is provided such that an upper looper thread crosses the lockstitch portion through the upper surface of the sewing body and a lower looper thread crosses the lockstitch portion through the lower surface of the sewing body to form an overlock portion. ing.

The looper drive section includes a crank attached to a looper drive shaft driven by the lower shaft, a lower looper drive link connected to the crank, and a lower looper drive link connected to the lower looper drive link and supported by the machine frame. A lower looper mounting arm for supporting the looper, an upper looper mounting arm pivotally supported by the machine frame and supporting the upper looper, and an upper looper driving link connecting the lower looper driving link and the upper looper mounting arm.

The looper drive mechanism of this sewing machine transmits power from the lower shaft to the looper drive shaft when the overlock portion is formed, thereby forming the lockstitch portion and the overlock portion. And a clutch for forming a lockstitch portion by retracting and shutting off the power from the lower shaft to the looper drive shaft.

In such a looper drive mechanism of a sewing machine, an upper looper and a lower looper are provided below the needle plate, respectively.
Each sword point is arranged in the same direction so as to pass through the front side of the needle when viewed in the sewing direction, and the upper looper and the lower looper are moved upward so that their trajectories move in a plane substantially parallel to each other. By driving the looper and the lower looper, both the functions of the lockstitch and the overlock stitch can be performed, and they can be formed at once by one sewing machine.

When the overlock portion is formed, power is transmitted from the lower shaft to the looper drive shaft to form a lockstitch portion and an overlock portion. Can be switched by a clutch so as to form a lockstitch portion by cutting off the power from the motor to the looper drive shaft.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention in which a looper drive mechanism of a sewing machine according to the present invention is applied to a lock stitch overlock sewing machine will be described with reference to the drawings.

As shown in FIG. 1, a lockstitch overlock sewing machine includes a lockstitch forming mechanism 100 for forming a lockstitch portion composed of stitches parallel to and perpendicular to the surface of a sewn body, and a sewn body. And a looper drive mechanism 50 for forming an overhanging portion on the surface.

This lockstitch forming mechanism 100 is known (well-known).
(JP-A-49-117148, JP-A-52-154448, JP-A-53-10854).
7, JP-A-54-60052, JP-A-54-60052
-110049, JP-A-55-35676, JP-A-55-113490, JP-A-55-1
46190, JP-A-56-3091, etc.), and a detailed description thereof will be omitted. However, in brief, as shown in FIG. 2, the needle 1 fixed to the needle bar 11 and vertically moving with respect to the needle plate 8 to draw a locus L10 in the vertical direction.
0, and a shuttle 20 that performs a horizontal rotation movement that draws a locus L20 in the same cycle as the vertical movement of the needle 10. The upper thread 1 pierced through the needle 10 and the lower thread 2 stored in the shuttle 20 When the needle thread 10 pierced through the needle 10 that reciprocates vertically in the vertical direction through the sewn object at every feed of the sewn object placed on the needle plate 8 when the needle 10 rises from the bottom dead center of the needle 10 A stitch parallel to the surface of the body to be sewn under the needle plate 8 by storing the lower thread 2 and scooping it with the blade point 21 of the shuttle 20 which rotates horizontally so that the upper thread 1 and the lower thread 2 intersect. And a seam perpendicular to the seam. The needle bar 11 has a machine frame F at the upper end.
A needle bar drive unit MT1 having a needle bar crank, which is a motion conversion mechanism that is slidably supported in a vertical direction by a needle frame 12 pivotally supported by R, moves up and down. In addition, pot (sword point)
20 may be not only full rotation but also half rotation. In short, the locus L20 and the locus L10 of the needle 10 cross each other, and the needle thread 21 scoops the upper thread 1.

Further, as shown in FIG. 1, in the lock stitch overlock sewing machine, a sewer rotates a stitch changeover knob NB to switch a pattern stitch changeover dial DL to each rotation position to switch to various sewing modes. Thus, straight stitching, zigzag stitching, and the like can be performed. The lockstitch forming mechanism 100 corresponding to this sewing mode also has a well-known (well-known) structure.
JP-A-8-50853, JP-A-49-32754, JP-A-50-73754, JP-A-54-46
No. 46, JP-A-54-6643, JP-A-54
-120057, JP-A-55-16676, JP-A-55-216, JP-A-55-4787.
JP-A-55-8406), 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 a pattern stitch generating device (shown in the drawing) that generates zigzag stitching and pattern stitching in cooperation with the cloth feeding. ) And a stitch switching device 110. In the lock stitch overlock sewing machine shown in FIG. 1, the pattern stitch generating device and the stitch switching device 110 are unitized,
The pattern stitch generating device is incorporated at the rear of the stitch switching device 110.

As shown in FIGS. 3 and 4, the stitch switching device 110 displays a stitch switching shaft 111 which is rotated by operating a stitch switching knob NB to set a pattern stitch, and various stitches. A pattern stitch change dial DL fixed to the operation-side shaft end of the stitch change shaft 111;
When a stitch is selectively switched by operating B, a necessary cam is selected from various cams of the pattern stitch generating device, and a mechanism for setting a needle swing amount, a needle swing position, and a needle feed amount is provided.

The pattern stitch generating device and the stitch switching device 110 are connected to the lockstitch forming mechanism 1 via the needle drop controller 520.
00 is drive-controlled. The needle drop controller 520 has one end connected to the pattern stitch generating device and the other end connected to the lockstitch forming mechanism 100.
And a needle bar puller 526 for reciprocating the needle bar 11 left and right with the needle frame 12 of the needle bar driver 120 by driving from the pattern stitch generator. And a needle drop conversion arm 536 engaged with the needle drop conversion cam 527 and rotatably fixed to the machine frame FR with a step screw 537. Needle drop conversion link 539 to needle drop conversion arm 536
And a needle drop conversion claw 522 that is connected to the needle bar pull bar 526 and is engaged with the needle bar pull bar 526.

A spring hook pin 526c is attached to the needle bar pull bar 526.
And a tension spring 529 is stretched between the spring hook pin 526c and the machine frame FR, so that the needle bar pull bar 526 is constantly urged leftward when the sewing machine is viewed from the front. ing. In addition, a needle drop conversion pin 526d that engages with the needle drop conversion claw 522 protrudes from the needle bar pull bar 526. The needle drop conversion claw 522 that engages with the needle drop conversion pin 526d is
The needle drop adjusting plate 521 is fixed to the needle drop adjusting plate 521 with a screw 525. The needle drop adjusting plate 521 is rotatably connected to one end of the needle drop converting link 539 by a screw 523. The needle drop adjusting plate 521 and the needle drop converting claw 522 fixed by the screw 525 are rotatably fixed to the machine frame FR by the screw 524 in an integrated state. The other end of the needle drop conversion link 539 is rotated by a screw 540 to an intermediate arm 536c protruding toward the needle drop conversion link 539 near a hole 536e through which the step screw 537 of the needle drop conversion arm 536 is inserted. They are freely connected. In addition, a safety pin 536b is protruded from an upper arm 536a disposed above the needle drop conversion arm 536 so as to engage with the needle drop conversion cam 527. The needle drop conversion cam 527 has a safety pin 536 of the needle drop conversion arm 536.
The recess 527a for making b rush into is formed,
Lower arm 536d arranged below needle drop conversion arm 536
A tension spring 538 is stretched between and the machine frame FR. Thus, the needle drop converting arm 53 can be viewed from the front of the sewing machine.
6 is repelled clockwise around the stepped screw 537, so that the recess 527a of the needle drop conversion cam 527 is formed.
The safety pin 536b of the needle drop conversion arm 536 can be made to protrude.

Further, the needle drop control unit 520 is provided with an overlock sewing switching button B provided on a front cover (not shown) of the sewing machine main body.
The needle drop conversion arm holding plate 5 which is operated by T to rotate the needle drop conversion arm 536 clockwise when the sewing machine is viewed from the front.
32. The overlock switch button BT is always repelled by the compression spring 534 in a direction away from the sewing machine main body front cover, and is prevented from coming off the sewing machine main body front cover by the elasticity of the compression spring 534. The retaining ring 535 locks the sewing machine main body front cover such that the pressing operation is possible. Needle drop conversion arm holding plate 53
2 has a receiving portion 532a formed at one end for pressing with the tip of the overlock switching button BT, and a needle drop converting arm 53 at the other end.
A holding portion 532b that supports the end of the upper arm 536a of the sixth arm 536a is formed. Such a needle drop conversion arm holding plate 532 is
Needle drop conversion arm holder 5 fixed to machine frame FR with screw 531
30 is attached rotatably by a step screw 533. Further, in order to repel the needle drop conversion arm holding plate 532 clockwise when viewed from above, the needle drop conversion arm holding plate 532 has a spring hook portion 532c, and the needle drop conversion arm holding base 530 has A spring hook portion 530a is formed, and a tension spring 5 is provided between the spring hook portion 532c and the spring hook portion 530a.
40 is stretched. As a result, the holding portion 532b of the needle drop conversion arm holding plate 532 is pressed against the end of the upper arm 536a of the needle drop conversion arm 536. Further, the needle drop conversion arm holding base 530 is provided with a stopper 532b for restricting the push when operating the overlock sewing switching button BT. Accordingly, when the overlock sewing switching button BT is pressed in, the needle drop conversion arm holding plate 532 rotates counterclockwise around the step screw 533 as viewed from above,
The rotation is regulated by the stopper 532b of the needle drop conversion arm holding base 530, and the push-in limitation when operating the overlock sewing switching button BT is achieved.

The lockstitch forming mechanism 100 thus configured
Will be described with reference to FIGS. 1 and 5.

The needle 10 is provided with a machine frame F of a lockstitch overlock sewing machine.
The rotation shaft, which is rotatably supported by R, that is, from the upper shaft S1 to the needle bar driving unit M
Move up and down via T1. The upper shaft S1 is provided with a balance 730 for pulling up and feeding out the needle thread 10 and a motion conversion mechanism 71.
(FIG. 10). This upper axis S1 is
The motor M is driven to rotate by a hand pulley HP via a timing belt TB1. A needle frame 12 for supporting a needle bar 11 to which the needle 10 is fixed slidably in the vertical direction.
Is a needle bar pull bar 5 driven and controlled by the pattern stitch generating device.
26 shifts the left / right position for each stitch. The needle plate 8 is formed in a horizontally long shape so that the needle drop hole PS can cope with the shift of the left and right positions of the needle 10.

The hook 20 is provided with a machine frame F of a lockstitch overlock sewing machine.
The shaft is rotated from a rotating shaft supported by R, that is, a lower shaft S2, via a shuttle driving screw gear MT2 which is a motion converting mechanism. The hook driving screw gear MT2 changes the rotational motion from the lower shaft S2 by 90 degrees in the feed direction and then transmits it to the hook 20. The driven gear 202 is fixed to the hook 20 and the driving gear 201
(FIG. 6) is fitted and fixed to the lower shaft S2. Lower shaft S2
Is synchronized with the upper shaft S1 by the timing belt TB2 and 2
It is rotationally driven at double speed (1: 2). This pot 20
The timing is adjusted so that the needle point 21 of the shuttle 20 scoops the loop of the needle thread 10 when the needle 10 rises from the lowest point by two rotations with respect to the vertical movement of one stitch.

The feed amount of the feed dog FB for feeding the cloth is also driven and controlled by the pattern stitch generating device. The cloth feed motion of the feed dog FB is driven by a feed drive unit 120 having a triangular cam from the lower shaft S2, and the feed drive unit 120 raises the feed dog FB to push up the sewn body. The feed dog FB is moved forward 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 step of feeding.

The overlock sewing machine with a lock stitch is shown in FIGS.
As shown in the figure, a substantially circular locus L above and below the needle plate 8
The reciprocating motion of drawing 30 is made, and the trajectory L of the needle 10 above the needle plate 8
The upper looper 30 intersecting with the needle 10 and a substantially arc-shaped trajectory L40 below the needle plate 8 are pierced by the lower looper 40 intersecting with the trajectory L10 of the needle 10 and the trajectory L30 of the upper looper 30, respectively. Further, a looper drive mechanism 50 is provided which forms the overcast portion 7 with the upper looper thread 3 and the lower looper thread 4.

The looper driving mechanism 50 is provided with the upper looper 3
0, the lower looper 40 is provided below the needle plate 8, respectively.
The sword tips 31, 41 are arranged in the same direction so as to pass through the front side of the needle 10 when viewed in the sewing direction, and the trajectories L30, 40 of the upper looper 30 and the lower looper 40 are substantially parallel to each other. It drives the upper looper 30 and the lower looper 40 to move in a parallel plane, and draws a locus L30 of the needle 10 and an arc-shaped locus L30 that crosses above the needle plate 8 and penetrates the needle plate 8. When the upper looper 30 descends from the top dead center, the upper looper thread 3 pierced through the upper looper 30 that reciprocates is scooped by the needle 10 descending from the top dead center, and the locus L10 of the needle 10 When the lower looper 40 moves from one end to the other end of the lower looper 40, the lower looper thread 4 pierced by the lower looper 40 that reciprocates by drawing a locus L40 that intersects the locus L30 of the upper looper 30 with the needle plate 8 Needle 1 descending below
When the lower looper 40 moves to the other end, the lower looper thread 4 is lifted from the lower dead center by the upper looper 30 to scoop the upper looper thread 3 and the lower looper thread 4 so that the lower looper thread 4 and the lower looper thread 4 move to the edge of the sewing body 5. 5
c and crosses the upper looper thread 3 onto the upper surface 5 of the body 5 to be sewn.
a looper drive section 60 (FIG. 6) so that the lower looper thread 4 passes through the lower surface 5b of the workpiece 5 and intersects with the lockstitch portion 6 to form an overhang portion 7. , FIG. 7)
It has.

The looper driving section 60 is provided below the needle plate 8, and as shown in FIGS. 6 and 7, the rotational movement from the lower shaft S2 is transmitted via a clutch 500, which will be described later.
61b attached to one end of a looper drive shaft 61 driven by the motor, a lower looper drive link 62 connected to the crank 61b, and a lower looper mounting arm connected to the lower looper drive link 62 and carrying the lower looper 40 63,
An upper looper mounting arm 64 that is supported by the machine frame FR and carries the upper looper 30 at one end, and an upper looper driving link 65 that connects the lower looper driving link 62 and the upper looper mounting arm 64 to each other. Are incorporated in a looper base 601 attached to the machine frame FR. Specifically, the looper drive shaft 61 is rotatably fixed to the looper base 601, and the crank pin 61 c of the crank 61 b is rotatably connected to one end of the lower looper drive link 62. The other end of the lower looper drive link 62 is rotatably connected to one end of a lower looper mounting arm 63.
The other end of 3 is supported by a looper base 601. Also,
The other end of the upper looper mounting arm 64 is pivotally attached to an upper looper mounting arm shaft 602 fixed to the looper base 601.

The overcasting operation by the looper driving unit 60 will be described with reference to FIGS. 5, 6, 7, and 8. FIG.

When the lower shaft S2 rotates, the looper drive shaft 61 rotates via the clutch 500, and the lower looper drive link 62 connected to the crank 61b of the looper drive shaft 61 converts this rotation to left and right reciprocation. Convert. When the lower looper drive link 62 reciprocates left and right, the lower looper mounting arm 63 swings about a pivot point of the lower looper mounting arm 63 with respect to the looper base 601, so that the lower looper mounting arm 63 carries the lower looper mounting arm 63. 40 swings in an arc from right to left of the needle 10 when the sewing machine is viewed from the front below the needle plate 8 (FIG. 2A). When the lower looper drive link 62 reciprocates left and right, the lower looper drive link 62
The upper looper mounting arm 64 is connected to the upper looper mounting arm 64 by the upper looper driving link 65 connecting the upper looper mounting arm 64 and the upper looper mounting arm 64.
The left-right reciprocating motion is converted to the up-down reciprocating motion around the upper looper mounting arm shaft 602 of FIG. When the upper looper mounting arm 64 reciprocates up and down about the upper looper mounting arm axis 602, the upper looper 30 moves the sewing machine from the right side of the needle 10 when viewed from the front and below the point 41 of the lower looper 40 from the front. It swings in an arc between the left side of the needle 10 and above the needle plate 8 (FIG. 2A).

The clutch 500 for transmitting / disconnecting 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 51 at the time of forming the overcast portion 7, and transmits the power to the lockstitch portion 6. When the lock stitch portion 7 is formed, the upper looper 30 is retracted at the bottom dead center when the lock stitch portion 6 is formed, and the power is cut off from the lower shaft S2 to the looper drive shaft 51 to form the lock stitch portion 6 (FIG. 2). (B)), a looper drive screw gear MT3 as a motion conversion mechanism is provided (FIG. 1). As shown in FIG. 6, 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 driven gear 509 is a looper base. The driving gear 505 is fixed to the other end of the looper drive shaft 61 rotatably fixed to the driving gear 601.
Is slidably fitted on the lower shaft S2.

The clutch 500 is fixed to the machine frame FR with screws 504 and fitted to a concave portion 505b formed at one end of the driving gear 505, and is fixed to one end of the lower shaft S2. A clutch receiver 506 having an end face formed with a clutch engaging recess 506a for fitting a clutch claw 505c formed at the other end of the driving gear 505, and a driving gear 2 of the hook driving screw gear MT2.
01 and the driving side gear 50 of the looper drive screw gear MT3
5 and is loosely fitted to the lower shaft S2 so as to be located between
The clutch spring 508 resiliently reciprocates in a direction in which the clutch pawl 505c of FIG. 502 is slidably mounted by a looper drive screw gear M
It has a clutch switching link 501 formed at one end with an L-shaped tip portion 501a that fits into a moving groove 505a formed in the driving side gear 505 of T3.

As shown in FIGS. 3 and 4, the clutch switching link 501 of the clutch 500 has a needle drop controller 520.
Are connected to a clutch control unit 510 that operates in conjunction with. The clutch control unit 510 connects the other end of the clutch switching link 501 to the end of the lower arm 536d of the needle drop conversion arm 536 of the needle drop control unit 520.
11 is provided. This clutch control link 511 is
An elongated hole 511a is drilled at one end where it is connected to the end of the lower arm 536d of the needle drop conversion arm 536, and can be slid by being connected to the needle drop conversion arm 536 with a step screw 514. Also, the clutch switching link 5 of the clutch control link 511
The other end of the clutch switching link 501 is provided with a connecting hole 511b at the other end connected to the other end of the clutch switching link 501.
01b is provided, and the clutch control link 51
A connection piece 512 is loosely fitted in the first connection hole 511b, and a clutch switching link 501 is fitted to the connection piece 512 by a screw 513 and a washer 515 so that the position thereof can be adjusted by an adjustment long hole 501b.
It is fixed at. Further, the clutch control link 511
And a needle drop conversion arm 536
A tension spring 517 is stretched between a spring hook hole provided in the lower arm 536d. As a result, the clutch control link 511 is always repelled in the direction in which it is drawn to the needle drop conversion arm 536.

When performing overcasting in the clutch 500 and the clutch control unit 510 configured as described above, the needle drop converting arm 536 rotates the sewing machine clockwise as viewed from the front due to the elasticity of the tension spring 538. Therefore, the clutch control link 511 connected to the end of the lower arm 536d of the needle drop conversion arm 536 moves leftward, so that the clutch switching link 501 connected to the clutch control link 511 also moves leftward. Moving. When the clutch switching link 501 moves to the left, the L-shaped tip 501a of the clutch switching link 501 fitted into the moving groove 505a of the driving side gear 505 of the looper drive screw gear MT3.
Moves the driving side gear 505 to the left, the concave portion 505b of the driving side gear 505 is disengaged from the looper driving screw gear stopper 503, and the concave portion 505b of the clutch receiving portion 506a of the clutch receiver 506 fixed to the lower shaft S2. The clutch pawl 505c of the driving gear 505 is engaged (FIG. 9).
(A)). As a result, the rotational motion of the lower shaft S2 is transmitted to the driven gear 509 via the driving gear 505.
The upper looper 30 and the lower looper 40 of the looper driving unit 60 are driven.

When the overcast sewing is completed, the needle drop converting arm 536 rotates counterclockwise when the sewing machine is viewed from the front, against the elasticity of the tension spring 538. Since the clutch control link 511 connected to the end of the lower arm 536d of 536 moves rightward, the clutch switching link 501 connected to the clutch control link 511 also moves rightward. When the clutch switching link 501 moves rightward, the looper drive screw gear M
The L-shaped tip 501a of the clutch switching link 501 fitted in the moving groove 505a of the driving gear 505 of T3 moves the driving gear 505 rightward, and this driving gear 505
Of the clutch spring 508 can be fitted to the looper driving screw gear stopper 503 against the resilience of the compression spring 508, and the clutch engaging recess 506a of the clutch receiver 506 fixed to the lower shaft S2 is connected to the driving gear 505. Clutch claws 5
05c (FIG. 9 (b)). 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.

The lock-stitch overlock sewing machine provided with such a looper drive mechanism 50 further includes a motion conversion mechanism 71 which is linked to the rotation axis of the lock-stitch overlock stitch machine, that is, the upper shaft S1.
An upper knife 72 that moves up and down via (FIGS. 10 and 11);
Cloth 5 (FIG. 2) by upper knife 72 and lower knife 73 which cooperates
May be provided with a scalpel drive mechanism 70 for cutting the cloth edge 5c.

The knife drive mechanism 70 includes a knife drive 74 pivotally supported by the machine frame FR and slidably guiding the upper knife 72.
(FIGS. 1 and 10) are provided.

The motion converting mechanism 71 transmits power to the upper knife 72 when the knife driving section 74 operates the knife.
When the knife is not operated, the upper knife 72 is pivoted to the retracted position to shut off the power to the upper knife 72 (FIG. 10).
It is connected to.

The motion conversion mechanism 71 is shown in FIGS.
1. As shown in FIG. 12, four links 76, 77 (78), 79, 8 connecting the upper shaft S1 as a rotating shaft and the machine frame FR.
0, a first link 79 of the first four-link chain LK1 and a link N4 of the machine frame FR.
And a second four-node rotating chain LK2 composed of four links 79, 81, 82, and 83 in which the driving unit 751 of the clutch 75 is used as another link 82. Note that, in the first four-bar rotation chain LK1, the link 77
The link 78 is fixed to the
It is connected to. The link 76 is a fixed link.

In the embodiment shown in FIG. 11, the motion converting mechanism 71 takes out motion from a mechanism for driving the balance 730 up and down from the upper shaft S1 as a rotation axis, converts the motion, and moves the upper knife 72 up and down. is there. However, the motion conversion mechanism 71 extracts the motion from the mechanism for driving the needle 10 up and down from the upper axis S1 as the rotation axis, converts the motion, and converts
2 may be moved up and down. The balance 730 is driven up and down by four links 76, 77 (78), 79, 80 from the upper shaft S1.

As shown in FIGS. 10 and 13, the clutch 75 has a pin 84 formed on the other link 82 as a driving section 751 and a pin 84 formed on the upper knife 72 as a driven section 741 to be fitted. And a long groove 85. Pin 84
Is screwed with a nut 753 into a mounting hole 752 at the bent lower end of another link 82 as a driving portion 751.

A lower knife 73 is slidably mounted on the knife drive section 74 on a knife drive plate 742 as a driven section 741. In order to achieve this sliding structure, the lower knife 73 is fixed to the sliding plate 744 by screws 743. The protrusion 746 of the pivoting member 745 fits into the opening 747 of the sliding plate 744 and the opening 748 of the female drive plate 742 to stop the stopper 749.
The pivoting member 745 is fixed with a screw 760. Therefore, the knife driving section 74 is provided with the sliding plate 744, that is, the lower knife 73.
Are slidably mounted within the relative dimensions of the openings 747, 748 and the protrusion 746.

An upper knife 72 is mounted on a knife drive plate 742 of the knife drive section 74 by a pin 761 so as to be replaceable. A knife-side pressure repelling member 88 for pressing the upper knife 72 against the lower knife 73 is provided. The female-side pressure repelling member 88 is formed of an elastic U-shaped member and is pivotally attached to the sliding plate 744 by a pin 763.
The elastic U-shaped member 762 is fitted in the state in which the upper knife 72 is attached to the lower knife 7 while the elastic U-shaped member 762 is held.
3 is pressed.

As shown in FIGS. 14 and 15, the lower knife 73 positions the knife driving section 74 in the positioning recess 86a of the positioning plate 86 of the needle plate 8 with respect to the needle drop position PS of the needle 10 when the knife is actuated. It has a positioning locking portion 87. Positioning plate 86 having positioning recess 86a formed therein
Is configured so that the sewing width W can be adjusted to the left and right so as to be variable with respect to the needle drop position PS. That is, the positioning plate 86 is incorporated into the concave portion 8a provided in the needle plate 8 so as to be adjustable in the left and right directions so as to be variable in the sewing width W direction, and is fixed by screws or the like after positioning.

The scalpel driving section 74 has a lower scalpel 73 slidably mounted thereon, and presses the positioning locking portion 87 against the positioning recess 86a of the positioning plate 86 of the needle plate 8 when the scalpel is actuated. 89 are provided. The positioning repelling member 89 is inserted into a mounting hole formed in the pivot member 745 and is fixed to the receiving plate 764 by the pin 763 and the pivot member 7.
45, and the positioning locking portion 8
7 is pressed against the positioning recess 86a of the positioning plate 86.

The pivot member 745 of the knife drive 74 is
65 pivotally supports the pivot hole 767 of the stopper 766. The stopper 766 is fixed to the machine frame FR by a retaining arm 768. In this manner, the female drive unit 74 is
To guide the upper knife 72 slidably.

The positioning repelling member 89 and the receiving plate 76
4 without using the knife driving unit 7 as shown in FIG.
4 is a positioning eccentric cam 90 which slidably mounts the lower knife 73 and fits the positioning locking portion 87 into the positioning recess 86a of the positioning plate 86 of the needle plate 8 when the knife is actuated.
May be provided. The scalpel drive section 74 having the eccentric cam 90 includes a scalpel drive body 942 provided with a groove 85 ′ to be fitted to the pin 84 of the drive section 751, which is a component of the clutch 75, and to which the upper knife 72 is fixed. This female driver 942
Sliding guides 946 arranged side by side with the sliding guides 94
6, a sliding body 944 to which the lower knife 73 is fixedly attached,
These three parts are, from above, a scalpel driver 942 and a sliding guide 9
46 and a sliding shaft 948 that is slidably fitted in the order of the sliding body 944.

The sliding guide 946 is provided with a guide groove in which a convex portion 944a formed on the sliding member 944 is slidably fitted in the axial direction of the sliding shaft 948. The pivot member 945 is fixed. The sliding guide 946 is fixed to the sliding shaft 948 with screws. The sliding body 944 has a groove as a cam follower at one end, and is vertically moved by the rotation of a positioning eccentric cam 90 rotatably mounted by an operation knob 91 around a shaft hole formed in the pivoting member 945 as an axis. Will move. Further, a knife-side pressure elastic member 950 for pressing the upper knife 72 against the lower knife 73 is fixed to the knife driving body 942. Further, the pivot member 945 of the scalpel driving unit 74 is pivotally supported by a pin in a pivot hole 767 of the stopper 766.
The stopper 766 is fixed to the machine frame FR by a retaining arm 768. In this way, the knife driving section 74 is pivotally supported by the machine frame FR and guides the upper knife 72 slidably.

According to the scalpel drive section 74 having such a configuration, the rotation of the operation knob 91 causes the positioning eccentric cam 90 to be eccentric and the lower knife 73 to be moved upward. The state in which the positioning locking portion 87 is fitted in the positioning recess 86a of the positioning plate 86 of the needle plate 8 can be released. Also,
By rotating the operation knob 91, the lower knife 73 is moved downward, and the positioning locking portion 87 of the lower knife 73 can be fitted into the positioning recess 86a of the positioning plate 86 of the needle plate 8.

The lock stitch overlock operation by the lock stitch overlock sewing machine thus configured will be described below.

As shown in FIG. 2, the stitches of the lock stitch overlock stitch include a lock stitch portion 6 composed of an upper thread 1 and a lower thread 2, an upper looper thread 3 which is two looper threads, and a lower looper thread. 4 and is formed by the lock stitch portion 6 and the overlock portion 7 intersecting each other. That is, the upper thread 1 and the lower thread 2 form stitches 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 main stitch portion 6 is formed by forming a stitch that crosses the vicinity of the center in the thickness direction and penetrates the cloth 5.

On the other hand, the upper looper thread 3 and the lower looper thread 4
Are formed at the edge 5c of the cloth 5 to prevent fraying of the edge 5c. The upper looper thread 3 crosses each other at the edge 5c of the cloth 5, and the upper looper thread 3 passes through the upper surface 5a of the cloth 5. 6, the lower looper thread 4 passes through the lower surface 5b of the cloth 5 and crosses the lower end of the lockstitch portion 6.

As described above, the stitch of the overlock stitch is formed by 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, and the upper thread With respect to the lock stitch portion 6 formed by the lower thread 1 and the lower thread 2, the overlock portion 7 formed by the looper threads 3 and 4 intersects on both sides of the cloth, so that both the lock stitch and the overlock portion are connected to each other, and the Is composed.

In such a lockstitch overlock sewing machine that forms a stitch formed by connecting both the lockstitch and the overlock stitch, first, when the sewer performs the overlock stitch, a sewing operation is performed. By operating the stitch switching knob NB to select, for example, straight stitching and a feed amount that is optimal for overcast stitching, the stitch switching shaft 111 of the stitch switching device 110 is inserted into the concave portion 527a of the needle drop conversion cam 527. It rotates to a position where the safety pin 536b of the needle drop conversion arm 536 can be inserted (FIGS. 3 and 4).

In this state, when the sewing person pushes the overlocking stitching switching button BT against the resilience of the compression spring 534, the tip of the overlocking stitching switching button BT holds the needle dropping conversion arm of the needle dropping control section 520. The needle-drop conversion arm holding plate 532 is rotated counterclockwise by pressing the receiving portion 532a of the plate 532, and the stopper 532b of the needle-drop conversion arm holding plate 532 retreats, so that it is supported by this stopper 532b. Needle drop conversion arm 536
Is rotated clockwise around the stepped screw 537 by the elastic force of the tension spring 538. Thus, the safety pin 515b of the needle drop conversion arm 536 is pushed into contact with the bottom surface of the concave portion 527a of the needle drop conversion cam 527 (FIGS. 3 and 4).

When the needle drop conversion arm 536 rotates clockwise around the stepped screw 537, the needle drop conversion arm 53 rotates.
6 is connected to the needle drop conversion link 539.
Is pushed upward, and the integrated needle drop adjusting plate 521 and the needle drop converting claw 522 are rotated clockwise. The needle drop conversion claw 522 is rotated by the rotation of the needle drop conversion claw 522 via a needle drop conversion pin 526 d fixed to the needle bar pull bar 526.
The needle bar pull bar 526, which has been repelled to the left, is moved to the right (FIGS. 1, 3). Thus, the needle drop position can be shifted to the rightmost point that is optimal for overlock sewing regardless of the needle drop position control of the stitch switching device 110. The needle drop conversion claw 522 is fixed to the needle drop conversion claw 522 with a screw 525 in order to prevent the needle position accuracy of the rightmost point that is optimal for the overlock sewing from being deteriorated by an error caused by the part itself or assembly. When adjustment of the needle position is necessary, the screw 525 is loosened so that the position of the needle drop conversion claw 522 can be adjusted.

Further, the needle drop conversion arm 536 is
When it is rotated clockwise around the center, the needle drop conversion arm 5
Since the clutch switching link 501 moves leftward via the clutch control link 511 connected to the end of the lower arm 536d of FIG. 36 (FIGS. 1, 3, 4, and 6), the looper drive screw gear MT3 Groove 505 of the driving side gear 505
L-shaped tip part 5 of clutch switching link 501 fitted to a
01a moves the driving side gear 505 to the left, the concave portion 505b of the driving side gear 505 is disengaged from the looper driving screw gear stopper 503, and the clutch engaging concave portion 506a of the clutch receiver 506 fixed to the lower shaft S2. 9 is engaged with the clutch pawl 505c of the driving gear 505 (FIG. 9).
(B)). As a result, the rotational motion of the lower shaft S2 is transmitted to the driven gear 509 via the driving gear 505.
The upper looper 30 and the lower looper 40 of the looper driving unit 60 are driven.

As described above, the upper looper 3 of the looper driving section 60
0, in a state where the lower looper 40 can be driven, the upper thread 1 pierced by the needle 10 is
After penetrating the cloth 5 following the up and down movement of the needle 10 by 1, when the needle 10 starts to rise from the bottom dead center,
The upper thread 1 intersects the lower thread 2 by scooping the upper thread 1 of the upper thread 1, and when the upper thread 1 is pulled up by the needle 10 and the balance 730 returning upward, the lower thread 2 is formed by pulling up the lower thread 2. The above-described operation is repeated every time the cloth is fed, whereby a continuous lock stitch portion 6 is formed (FIG. 2).

In addition, when the upper looper 30 at the top dead center is reciprocated up and down by the upper looper mounting arm 64, the upper looper thread 3 is scooped by the needle 10 at the point P which is descending. As a result, the upper end of the lockstitch portion 6 and the upper looper thread 3 intersect at the upper surface of the cloth (FIG. 8A).

Next, when the lower looper mounting arm 63 reciprocates left and right, the lower looper thread 4 of the lower looper 40 moving rightward from the leftmost point is moved by the needle 10 descending from the top dead center at the point Q. By being scooped, the lower end of the lockstitch portion 6 and the lower looper thread 4 intersect at the lower surface of the cloth (FIG. 8B). Further, when the lower looper mounting arm 63 reciprocates left and right, the lower looper thread 4 retreating rightward is moved downward by the upper looper 30 rising from the lower dead center by the upper looper mounting arm 64 at the point S. By being scooped, the upper looper thread 3 and the lower looper thread 4 intersect with each other at the edge 5c of the cloth 5 to form the overcast portion 7 (FIG. 2). The overlock portion 7 is also repeated with one cycle of cloth feeding as one cycle, thereby obtaining a stitch in which the overlock portion 7 intersects every single stitch as shown in FIG. .

The rotation axis of the sewing machine, the upper axis S in the illustrated example,
The rotation motion of 1 is converted into a vertical motion through a motion conversion mechanism 71 (FIGS. 1, 10, 11, and 12) linked therewith. That is, when the upper shaft S1 rotates, the links 77 and 78 of the first four-bar rotation chain LK1 are used as cranks and the link 8
0 is a connecting rod, and the link 79 is rocked as a rocker arm. The swing of the link 79 causes the second four-joint rotary chain L
The link 81 of K2 is swung, 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, LK2, and a guide plate 755 fixed to the machine frame FR by drawing an approximate straight line trajectory in the suburb PL point of the driving unit 751. The guide pin 754 fixed to the PL point of the link 82 penetrates the guide elongated hole 755a and supports the recoil from the knife driving unit 74 (FIGS. 10, 11, and 1).
3). As a result, the movement of the drive unit 751 in the horizontal direction is restricted, and only the vertical movement is obtained in one stroke of the upper shaft S1 with the stroke t (FIG. 11).

The vertically moving motion converted by the motion converting mechanism 71 is converted into a long groove 85 in which the pin 84 of the driving portion 751 of the clutch 75 and the pin 84 of the female driving plate 742 of the female driving portion 74 as the driven portion 741 are fitted. Is transmitted to the upper knife 72 via the. A knife operating state in which the positioning locking portion 87 of the lower knife 73 is fitted in the positioning recess 86a of the positioning plate 86 of the needle plate 8 to position the knife driving portion 74 with respect to the needle drop position PS of the needle 10. (FIG. 14)
The upper knife 72 is slidably guided on the slide plate 744 by the knife drive plate 742 of the knife drive unit 74 pivotally supported by R. In this knife operating state, the knife driving section 74 is
5 is maintained in a vertical state around the long groove 5 and the longitudinal direction of the long groove 85 is oriented in the horizontal direction.
The pin 84 and the long groove 85 of the driven part 741 are transmitted with power and transmit power to the upper knife 72 when the knife driving part 74 operates the knife, and the upper knife 72 and the lower knife cooperating with the upper knife 72 by this vertical movement. 73, the cloth edge 5c of the cloth 5 is cut.

In this way, by cutting the cloth edge 5c of the cloth 5 and performing the main sewing or the like, the overlock sewing operation can be performed at the same time.

Further, in order to switch from the overlock stitch to the lockstitch, the sewing machine is stopped and then the stitch change knob NB is operated to select a mode other than the straight stitch.
The stitch switching shaft 111 rotates and the stitch switching shaft 11
Since the safety pin 536b of the needle drop conversion arm 536 is disengaged from the concave portion 527a of the needle drop conversion cam 527 fixed at a predetermined position of the needle drop conversion arm 536, the needle drop conversion arm 536 is stepped against the elasticity of the tension spring 538. It rotates counterclockwise around the screw 537 (FIGS. 1, 3, and 4). Accordingly, the intermediate arm 536c of the needle drop conversion arm 536 pulls the connected needle drop conversion link 539 downward, so that the integrated needle drop adjustment plate 521 and the needle drop conversion claw 522 rotate counterclockwise. . When the needle drop conversion claw 522 rotates counterclockwise, the resilient force of the tension spring 529 causes the needle bar pull bar 526 to move to the left, so that the needle position is optimal for lockstitching.

Further, the needle drop conversion arm 536 is
, The lower arm 536d of the needle drop conversion arm 536 attempts to move the clutch control link 511 to the right, but the looper drive screw gear M
If the concave portion 505b of the driving side gear 505 of T3 and the looper drive screw gear stopper 503 fixed to the machine frame FR are not at the same position, they cannot be fitted, so that the needle drop conversion arm 536 is attached to the lower arm 536d. Step screw 51 fixed to
4 slides rightward in the elongated hole 511a of the clutch control link 511 against the resilience of the tension spring 517 (FIGS. 1, 3, 4, 6, and 9). Therefore, 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 fit together rotates the hand pulley HP fixed to the upper shaft S1 to the timing position of the lowest point, the clutch control link Since 511 moves rightward due to the elasticity of the extension spring 517,
The L-shaped tip 501a of the clutch switching link 501 fitted in the moving groove 505a of the driving gear 505 is
05 can be moved to the right. This allows
The clutch pawl 50 of the driving-side gear 505 extends from the clutch engaging recess 506a of the clutch receiver 506 fixed to the lower shaft S2.
5c is dissociated, the rotational movement of the lower shaft S2 is cut off, and the driving gear 505 cannot rotate.
The upper looper 30 and the lower looper 40 can be retracted to predetermined positions below the needle plate 8.

In the above embodiment, the upper looper thread 3 and the lower looper thread 4 intersect all the adjacent lock stitches 6, respectively. For example, as shown in FIG. The overhang portions 7 may intersect every other one. In this case, the ratio of the number of rotations of the lower shaft S2 and the looper drive unit 60 may be set so that the upper looper 30 and the lower looper 40 move by one cycle of the two cycles of the movement of the needle 10. .

In the above embodiment, the stitches 1a and 2a of the upper thread 1 and the lower thread 2 are linear, respectively.
As shown in (c), the shape may be zigzag for each stitch, or may be a folded line for each of a plurality of stitches.

On the other hand, if the overlock switching button BT is not pushed in, even if the needle drop converting arm 536 is repelled clockwise around the stepped screw 537 by the resilient force of the tension spring 538, the needle is not moved. Since the rotation of the upper arm 536a of the drop conversion arm 536 is regulated by the holding portion 532b of the needle drop conversion arm holding plate 532, the concave portion of the needle drop conversion cam 527 can be used even when the lockstitch is selected by the stitch switching knob NB. The safety pin 536b of the needle drop conversion arm 536 does not enter the 527a (FIGS. 1 and 3). When other stitches are selected, the stitch switching knob NB is operated so that these stitches can be performed.
The needle drop conversion arm 53 is provided in the concave portion 527a of the needle drop conversion cam 527.
6 rotates to a position where the safety pin 536b cannot enter (FIGS. 1 and 3).

Therefore, in this state, the needle drop conversion claw 5
Reference numeral 22 does not move the needle bar pull bar 526 rightward, and the clutch switching link 501 of the clutch control unit 510 moves rightward due to the resilience of the tension spring 517. The clutch pawl 505c of the side gear 505 is in a state of being disengaged from the concave portion 506a of the clutch receiver 506 (FIG. 9A). Accordingly, the screw gear stopper 503 is engaged with the concave portion 505b of the driving side gear 505, and the rotational movement of the lower shaft S2 is interrupted, so that the driving side gear 505 cannot rotate. 40 can be retracted to a predetermined position below the needle plate 8.

In the non-operation state of the scalpel where only the main sewing is desired without cutting the cloth edge 5c of the cloth 5, as shown in FIG. 15, the sliding plate 744 is lifted or the operation knob 91 is operated.
The eccentric cam 90 is rotated (FIG. 16), and the lower knife 73 is rotated.
Of the positioning plate 8 of the needle plate 8
6 is released from the state in which it is fitted in the positioning recess 86a, and the knife driving section 74 is pivoted to the horizontal retreat position around the pin 765, so that the longitudinal direction of the long groove 85 is oriented in the vertical direction. Pin 8 of 75 drive unit 751
4 only floats in the long groove 85 of the driven portion 741 and shuts off the power to the upper knife 72.

In this manner, the cloth edge 5c of the cloth 5 can be easily operated by pivoting the knife driving section 74 to the horizontal retracted position.
It is possible to switch to an operation in which only the main sewing is performed without cutting the main sewing.

According to the preferred embodiment in which the looper drive mechanism of the sewing machine of the present invention is applied to a lock-stitch overlock sewing machine, a horizontal shuttle having horizontal rotation is used.
In addition to this, when the upper thread pierced through the needle rises from the bottom dead center of the needle, the upper thread and the lower thread are crossed to form a seam parallel to the surface of the body to be sewn and a vertical seam. Any shuttle can be used as long as the lock stitch portion can be formed.

The knife drive mechanism 70 and the needle drop control section 52
0, the clutch 500 and the clutch control unit 510 are not limited to the above-described structures. The knife drive mechanism 70 cuts the cloth edge to perform the overlock sewing with the lock stitch, and performs the lock sewing without cutting the cloth edge. The needle drop control unit 520 shifts the needle drop position in conjunction with the overlock stitching changeover button BT. The clutch 500 operates the lock stitch portion 6 and the overlock portion when the overlock portion 7 is formed. 7 and the lock stitch 6
Is formed, the clutch control section 510 may have any structure as long as the clutch control section 510 can control the clutch 500 in conjunction with the stitch switching knob NB.

Further, the looper drive section 60 is not limited to the above-described structure, and the upper looper 30 and the lower looper 40
, And are arranged in the same direction so as to pass through the front side of the needle 10 when viewing each of the sword tips 31, 41 in the sewing direction, and the locus of the upper looper 30 and the lower looper 40 is The upper looper 30 and the lower looper 40 are driven to move in planes substantially parallel to each other.
The upper looper thread 3 penetrates the upper looper 30 which reciprocates while drawing a circular locus crossing the locus of zero and the needle plate 8 and penetrating the needle plate 8, and the upper looper 30 descends from the top dead center. Sometimes, the lower looper 40 scoops with the needle 10 descending from the top dead center, and 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.
When the lower looper 40 moves from one end of the locus L40 to the other end, the lower looper thread 4 is stabbed with the descending needle 10 below the needle plate 8 and the lower looper 40 moves to the other end. The upper looper thread 4 rising from the bottom dead center scoops the lower looper thread 4, so that the upper looper thread 3 and the lower looper thread 4 intersect at the edge 5 c of the sewing body 5 and the upper looper thread 3 is attached to the sewing body 5. Crosses the lockstitch portion 6 through the upper surface 5a of the lower looper thread 4.
Any structure may be used as long as it can form an edge overhang portion 7 formed by crossing the lock stitch portion 6 through the lower surface 5b of the sewing target body 5.

[0079]

As described above, according to the looper drive mechanism of the sewing machine of the present invention, the upper looper and the lower looper are provided below the needle plate, respectively, and the point of the sword is viewed from the sewing direction in front of the needle. It is possible to drive the upper looper and the lower looper such that they move in the same direction so as to pass through the side surface of the upper looper and the lower looper so that their trajectories move on planes substantially parallel to each other. It can combine the functions of lock stitching and overlock stitching, and can stitch together multiple fabrics at the same time, overhang the edges of those fabrics, and minimize the labor cost of thread be able to.

According to the looper drive mechanism of the sewing machine of the present invention, the lockstitch and the overlock stitch can be separately formed by the needle and the two loopers. Seams can be realized, in which case
Other seams can be formed with only minor changes.

Further, at the time of forming the overlock portion, power is transmitted from the lower shaft to the looper drive shaft to form the lockstitch portion and the overlock portion, and at the time of forming the lockstitch, the upper looper is retracted at the bottom dead center and the lower shaft is retracted. Can be switched by the clutch so as to form a lockstitch portion by cutting off the power from the locker to the looper drive shaft, so that the time and effort for separating the lockstitch and the overlock stitch can be saved.

[Brief description of the drawings]

FIG. 1 is an overall perspective view showing an embodiment of a lockstitch overlock sewing machine to which a looper drive mechanism for a sewing machine according to the present invention is applied.

FIGS. 2A and 2B are explanatory views briefly showing the operation of a lockstitch overlock sewing machine to which the looper drive mechanism of the sewing machine according to the present invention is applied.

FIG. 3 is an exploded perspective view showing a stitch switching device, a needle drop control unit, and a clutch control unit in the looper drive mechanism of the sewing machine according to the present invention.

FIG. 4 is an explanatory diagram showing a needle drop control unit and a clutch control unit in the looper drive mechanism of the sewing machine according to the present invention.

FIG. 5 is a block diagram showing a drive system of the lockstitch overlock sewing machine to which the looper drive mechanism of the sewing machine of the present invention is applied.

FIG. 6 is an exploded perspective view showing a clutch control unit and a looper drive unit in the looper drive mechanism of the sewing machine according to the present invention.

FIG. 7 is a top view showing a looper drive unit in the looper drive mechanism of the sewing machine according to the present invention.

FIGS. 8A and 8B are explanatory views showing an operation state of a looper driving unit in the looper driving mechanism of the sewing machine according to the present invention, wherein FIG. 8A is a diagram in which a needle scoops an upper looper thread, and FIG. Diagram of scooping points.

FIGS. 9A and 9B are explanatory views showing an operating state of a clutch in the looper drive mechanism of the sewing machine according to the present invention, wherein FIG. 9A is a view in which power from the lower shaft to the looper drive shaft is cut off, and FIG. FIG. 4 is a diagram illustrating a state where power is transmitted to a looper drive shaft.

FIG. 10 is a perspective view showing a motion conversion mechanism and a knife drive unit in the knife drive mechanism used for the lockstitch overlock sewing machine.

FIGS. 11A and 11B are explanatory views showing an operation state of a motion conversion mechanism in a knife drive mechanism used for the lock stitch overlock sewing machine.

FIG. 12 is an explanatory view showing the operation of a motion conversion mechanism in a knife drive mechanism used in the lockstitch overlock sewing machine.

FIG. 13 is an exploded perspective view showing a motion conversion mechanism and a knife drive unit in the knife drive mechanism used in the lockstitch overlock sewing machine.

FIG. 14 is a perspective view showing a scalpel operation state in the scalpel drive mechanism used in the lockstitch overlock sewing machine.

FIG. 15 is a perspective view showing a non-operating state of a knife in a knife drive mechanism used for the lock stitch overlock sewing machine.

FIG. 16 is a perspective view showing a knife drive unit of another embodiment of the knife drive mechanism used in the overlock sewing machine, and viewed from the back side of the sewing machine.

FIG. 17 shows a stitch formed by a lock stitch overlock sewing machine to which the looper drive mechanism of the sewing machine of the present invention is applied, and (a).
Is an explanatory view of a stitch in which an overlock portion crosses at every glance of a lock stitch, (b) is an explanatory view of a stitch in which an overlock portion crosses every other or every two stitches, (c) () Is an explanatory view of stitches in which the main stitching portion has a zigzag shape for each stitch or a folded line shape for each of a plurality of stitches.

FIG. 18 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 ... lower thread 3 ... upper looper thread 4 ... lower looper thread 6 ... regular sewing part 7 ... .... Edge overhanging part 8 ... Needle plate 10 ... Needle 20 ... Hook 21 ... Sword tip 30 ... Upper looper 31・ ・ ・ ・ ・ ・ Sword tip 40 ・ ・ ・ ・ ・ ・ Lower looper 41 ・ ・ ・ ・ ・ ・ Sword tip 50 ・ ・ ・ ・ ・ ・ Loop drive mechanism 60 ・ ・ ・ ・ ・ ・ Loop drive section 61 ・ ・ ・ ・ ・ ・・ Loop drive shaft 61c ・ ・ ・ ・ ・ ・ Crank 62 ・ ・ ・ ・ ・ ・ Lower loop drive link 63 ・ ・ ・ ・ ・ ・ Lower looper mounting arm 64 ・ ・ ・ ・ ・ ・ Upper looper mounting arm 65 ・ ・ ・ ・ ・ ・··· Upper looper drive link 500 ·························································································· Looper arc Trajectory L40 ・ ・ ・ ・ ・ ・ arc shaped trajectory of lower looper

[Procedure amendment]

[Submission date] January 31, 2001 (2001.1.3)
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

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 ( patented ) .
No. 2541601 ). This attachment is
As shown in FIG. 18, a drive arm of a crank 1003 which is used by being fixed to a cloth presser bar 1001 and is pivotally supported by an attachment frame 1002 by a needle bar (not shown) carrying a needle 1011. 1003a is driven, and the driven arm 1003b is
The upper looper driving plate 1005 pivotally supported by the attachment frame 1002 via the base 4 is swung. The swing of the upper looper drive plate 1005 causes the upper looper 1007 pivotally supported by the attachment frame 1002 via the upper looper drive link 1006 to swing. On the other hand, the swing of the upper looper driving plate 1005 causes the upper looper driving plate 1 to move.
The lower looper drive plate 100 pivotally supported by the attachment frame 1002
8 is slid, and the lower looper driving plate 1008 is swung. The lower looper 10 pivotally supported by the attachment frame 1002 via the lower looper drive link 1009 by the swing of the lower looper drive plate 1008.
Swing 10. In this attachment structure, the upper looper 1007 has a needle 10 on the upper surface of a cloth (not shown).
11 so that it is inclined upward and to the left when viewed in the cloth feeding direction.
Must cross the needle 1011 at the lower surface of the cloth, so that it is inclined to the lower left when viewed in the cloth feed direction, and furthermore, the upper and lower loopers 1007, 1010 beside the cloth end.
Are inclined to cross each other. ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 13, 2001 (2001.3.1.
3)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0025

[Correction method] Change

[Correction contents]

Further, the needle drop control unit 520 is provided with an overlock sewing switching button B provided on a front cover (not shown) of the sewing machine main body.
The needle drop conversion arm holding plate 5 which is operated by T to rotate the needle drop conversion arm 536 clockwise when the sewing machine is viewed from the front.
32. The overlock switch button BT is always repelled by the compression spring 534 in a direction away from the sewing machine main body front cover, and is prevented from coming off the sewing machine main body front cover by the elasticity of the compression spring 534. The retaining ring 535 locks the sewing machine main body front cover such that the pressing operation is possible. Needle drop conversion arm holding plate 53
2 has a receiving portion 532a formed at one end for pressing with the tip of the overlock switching button BT, and a needle drop converting arm 53 at the other end.
A holding portion 532b that supports the end of the upper arm 536a of the sixth arm 536a is formed. Such a needle drop conversion arm holding plate 532 is
Needle drop conversion arm holder 5 fixed to machine frame FR with screw 531
30 is attached rotatably by a step screw 533. Further, in order to repel the needle drop conversion arm holding plate 532 clockwise when viewed from above, the needle drop conversion arm holding plate 532 has a spring hook portion 532c, and the needle drop conversion arm holding base 530 has A spring hook portion 530a is formed, and a tension spring 5 is provided between the spring hook portion 532c and the spring hook portion 530a.
40 is stretched. As a result, the holding portion 532b of the needle drop conversion arm holding plate 532 is pressed against the end of the upper arm 536a of the needle drop conversion arm 536. Further, the needle drop conversion arm holding base 530 is provided with a stopper 532b for restricting the push when operating the overlock sewing switching button BT. Thus, when the overlock switching button BT is pushed in, the needle drop conversion arm holding plate 532 rotates counterclockwise around the step screw 533 as viewed from above,
The rotation is regulated by the stopper 530b of the needle drop conversion arm holding base 530, and the pushing restriction when operating the overlock sewing switching button BT is achieved.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0027

[Correction method] Change

[Correction contents]

The needle 10 is provided with a machine frame F of a lockstitch overlock sewing machine.
The rotation shaft, which is rotatably supported by R, that is, from the upper shaft S1 to the needle bar driving unit M
Move up and down via T1. Further, the upper shaft S1 is movement the balance 730 to perform pulling on <br/> up feeding of the needle thread conversion mechanism 71 (FIG. 1
0) drives up and down. The upper shaft S1 is connected to a hand pulley H from a motor M via a timing belt TB1.
It is rotationally driven by P. The needle frame 12 that supports the needle bar 11 to which the needle 10 is fixed so as to be slidable in the vertical direction is shifted left and right by one stitch by a needle bar pull bar 526 driven and controlled by the pattern stitch generating device. Let it. The needle plate 8
The needle hole PS is formed in a horizontally long shape so that the needle drop hole PS can cope with a shift of the left and right positions of the needle 10.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0060

[Correction method] Change

[Correction contents]

When the needle drop conversion arm 536 rotates clockwise around the stepped screw 537, the needle drop conversion arm 53 rotates.
6 is connected to the needle drop conversion link 539.
Is pushed upward, and the integrated needle drop adjusting plate 521 and the needle drop converting claw 522 are rotated clockwise. The needle drop conversion claw 522 is rotated by the rotation of the needle drop conversion claw 522 via a needle drop conversion pin 526 d fixed to the needle bar pull bar 526.
The needle bar pull bar 526, which has been repelled to the left, is moved to the right (FIGS. 1, 3). Thus, the needle drop position can be shifted to the rightmost point that is optimal for overlock sewing regardless of the needle drop position control of the stitch switching device 110. In order to prevent the needle position accuracy of the rightmost point which is optimal for the overlock sewing from being deteriorated by an error caused by the part itself or assembly, the needle drop conversion claw 522 is fixed to the needle drop adjusting plate 521 with a screw 525. When adjustment of the needle position is necessary, the screw 525 is loosened so that the position of the needle drop conversion claw 522 can be adjusted.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0075

[Correction method] Change

[Correction contents]

In this manner, the cloth edge 5c of the cloth 5 can be easily operated by pivoting the knife driving section 74 to the horizontal retracted position.
This switching to work to perform only the sewing without cutting the
And it is possible.

[Procedure amendment 5]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4 ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 19, 2001 (2001.3.1.
9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

The pattern stitch generating device and the stitch switching device 110 are connected to the lockstitch forming mechanism 1 via the needle drop controller 520.
00 is drive-controlled. The needle drop controller 520 has one end connected to the pattern stitch generating device and the other end connected to the lockstitch forming mechanism 100.
It is connected to the needle bar drive portion MT1, a needle Bobiki bar 526 to reciprocate in the right and left needle bar 11 with the needle frame 12 of the needle bar drive portion MT1 by the drive from the pattern stitch generating device, the stitch changeover device 110 And a needle drop conversion arm 536 engaged with the needle drop conversion cam 527 and rotatably fixed to the machine frame FR with a step screw 537. Needle drop conversion link 539 to needle drop conversion arm 536
And a needle drop conversion claw 522 that is connected to the needle bar pull bar 526 and is engaged with the needle bar pull bar 526.

Claims (3)

[Claims] An object to be sewn placed on a needle plate by an upper thread penetrated by a needle that moves up and down in a direction perpendicular to the needle plate and a lower thread stored in a shuttle. When the upper thread pierced the needle that reciprocates in the vertical direction through the sewn body at every feed from the bottom dead center of the needle,
A stitch parallel to the surface of the sewn body and perpendicular to the seam parallel to the surface of the sewn body by scooping the lower thread under the needle plate and storing the lower thread with An upper looper for forming a lock stitch portion including a stitch, and performing a reciprocating motion to draw a substantially arc-shaped locus above and below the needle plate, and intersecting the locus of the needle above the needle plate; A substantially arc-shaped locus is drawn below the plate, and an overcast portion is formed by an upper looper thread and a lower looper thread pierced through a lower looper respectively intersecting with the locus of the needle and the locus of the upper looper. In the looper drive mechanism of the sewing machine, the upper looper and the lower looper are respectively provided below the needle plate, and are directed in the same direction so as to pass through the front side surface of the needle when viewing each blade point in the sewing direction. It is arranged, and the locus of the upper looper and lower looper The upper looper and the lower looper are driven so as to move in planes substantially parallel to each other, and the trajectory of the needle intersects above the needle plate and an arc-shaped trajectory penetrating the needle plate. The upper looper thread pierced through the upper looper that draws and reciprocates is scooped by the needle descending from the top dead center when the upper looper descends from the top dead center, and the trajectory of the needle and the upper The lower looper thread pierced through the lower looper that reciprocates in a reciprocating manner by drawing a trajectory that intersects with the trajectory of the looper descends below the needle plate when the lower looper moves from one end of the trajectory to the other end. When the lower looper moves to the other end, the upper looper that rises from the bottom dead center scoops with the needle, so that the upper looper thread and the lower looper thread are moved along the edge of the sewn body. Crosses the upper looper Crosses the lockstitch portion through the upper surface of the sewn body, and forms a loop overlock portion formed by the lower looper thread crossing the lockstitch portion through the lower surface of the sewn body. A looper drive mechanism for a sewing machine, comprising: 2. The looper drive section includes a crank attached to a looper drive shaft driven by a lower shaft, a lower looper drive link connected to the crank, and a machine frame connected to the lower looper drive link. A lower looper mounting arm pivotally supported by the lower looper, an upper looper mounting arm pivotally supported by the machine frame and supporting the upper looper, and an upper loop connecting the lower looper drive link and the upper looper mounting arm. 2. A looper drive mechanism for a sewing machine according to claim 1, further comprising a looper drive link. 3. When the overlock portion is formed, power is transmitted from the lower shaft to the looper drive shaft to form the lockstitch portion and the overlock portion. 3. The looper drive mechanism for a sewing machine according to claim 2, further comprising a clutch that retracts at a dead center and cuts off power from the lower shaft to the looper drive shaft to form the lockstitch portion.