JP2012166000A - Thread cutter for button sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thread cutter for a button sewing machine which is capable of easily and appropriately adjusting contact-sliding performance between knife edges of a movable knife and a fixed knife and maintaining the contact-sliding performance to reliably cut a predetermined part of a needle thread into a good appearance with a reduced remaining length of the thread.SOLUTION: After a button sewing step and/or a wound thread shank step, a knife mechanism 21 in which a fixed knife 16 and a movable knife 14 are integrated in an openable and closable manner is driven to swing from a position on a side of a needle plate 15 to a position under the needle plate 15. A needle thread hooking guide part 16b provided on the fixed knife 16 guides a part 12a of a needle thread on the side extending to an end of a button sewing thread 10 and/or a wound thread shank thread 37, out of two parts 12a and 12b of the needle thread extending between a button sewing thread 10 and/or a wound thread shank thread 37 and a looper 9 into a substantially triangular loop form, to the knife edge part 16a. The part 12a of the needle thread is sandwiched and cut by a slide contact action between knife edges 16a and 14a of the movable knife 14 and the fixed knife 16.

Description

  The present invention is equipped with a button sewing machine that sews various buttons such as flat buttons and marble buttons on fabrics such as men's and women's clothing, and is sewn on the fabrics by the buttoning process and / or buttoning process. After the root winding process for reinforcing the buttoning thread by winding the thread around the buttoning thread between the selected button and the fabric, the width gradually increases toward the top between the buttoning thread and / or the root winding thread and the looper. A knife mechanism that cuts the needle thread portion that is connected to the end of the buttoning thread and / or the root winding thread, out of the two needle thread sections that are stretched and held in a narrow, substantially triangular loop shape. The present invention relates to a thread trimming device for a buttoned sewing machine.

  As a thread trimming device of this kind of button sewing machine, conventionally, a movable knife is generally held in a substantially triangular loop shape by linearly reciprocatingly moving along a horizontal plane below the needle plate. Of the two needle thread portions, one that is configured to push out the needle thread portion that is connected to the end portion of the buttoning thread and / or the root winding thread has been widely used.

  However, in the case of a push-cut type thread trimming device with a thin movable knife that has been generally used in the past, strong tension does not work, and in order to demonstrate a reliable sharpness against the needle thread part that seems to be staggered, It is necessary to use a thin movable knife having a sharp edge like a cutter blade. For this reason, the sharpness of the movable knife is liable to be rapidly lowered due to the sharp edges and breakage of the blade of the movable knife due to short-term use. When the sharpness is reduced, the needle thread portion to be cut by receiving the pressing force of the movable knife is pushed and bent just below the needle plate, so that the cutting position of the needle thread portion is lowered from the end of the button attachment thread. As a result, the remaining yarn length becomes longer, and the longer remaining needle thread portion is exposed and noticeable on the surface of the fabric, which tends to deteriorate the appearance.

  In addition, in order to shorten the thread remaining length, the reciprocating drive movement path of the movable knife is set as close as possible to the lower surface of the needle plate. If so, the sharp and thin movable knife with a sharp edge like a cutter blade is set. Will push and cut the narrow part of the upper part of the loop of the two needle thread parts that are held in a substantially triangular loop shape. As a result, the needle that does not require cutting on the side that is inserted and held in the needle hole The two needle thread portions forming the loop including the thread portion are likely to be cut together.

In order to eliminate the inconvenience as described above, the applicant of the present invention has provided a movable knife capable of reciprocating and swinging along the water surface between the lower position of the needle plate and the lateral position of the needle plate, and the needle plate. Patent application for a thread trimming device having a knife mechanism that is fixed (formed) to the movable knife and slidably contacted with the movable knife, and the contents of the patent application have already been published (for example, , See Patent Document 1).
The knife mechanism described in Patent Document 1 is an approximately formed by two needle thread portions when the movable knife swings forwardly from the lateral position of the needle plate toward the lower position of the needle plate. Enter the wide part below the triangular loop space and guide the needle thread part on the side of the two needle thread parts connected to the end of the buttoning thread and / or root winding thread relatively upward. Thus, the needle thread portion guided to be pulled up is cut by the sliding contact action between the movable knife and the fixed knife.

  JP 2010-188106 A

  However, in the thread trimming device disclosed in Patent Document 1 described above, the movable knife is fixed to the movable knife such that the movable knife is attached to the reciprocating drive moving member and the fixed knife is fixed (formed) to the needle plate. Since the knife is separated separately and attached to different members separately, the blade edges of both knifes are smooth without gaps and without mutual interference such as the blade edges collide with each other. Therefore, it is very difficult to properly adjust the sliding movement so that the sliding movement is performed. In order to optimize the friction between the blade edges of both knives, extremely high accuracy is required not only for the production processing accuracy of both knives but also for the production and assembly accuracy of the members to which both knives are attached. If even a slight error occurs in the manufacturing accuracy of both knives and the manufacturing and assembly accuracy of their attachment members, the sliding performance of the blade edges of both knives deteriorates, and there is a mistake in the predetermined thread trimming. It is liable to cause a failure such as occurrence or damage due to collision between the blade edges of both scalpels.

  Furthermore, in the initial stage of assembly, even if the sliding performance can be adjusted properly, the blade edges of both scalpels wear due to repeated thread trimming, and rattling or the like may occur due to wear of the scalpel mounting members. In such a case, there has been a problem that the rubbing performance gradually deteriorates and the above-described defective situation occurs at an early stage.

  The present invention has been made in view of the above circumstances, and it is easy to appropriately adjust the sliding performance between the blade edges of the movable knife and the fixed knife, and the proper sliding performance can be maintained over a long period of time. It is an object of the present invention to provide a thread trimming device for a button-attached sewing machine that can reliably maintain only a predetermined needle thread portion and can cut the thread remaining length into a state of good appearance with a short thread remaining length. .

  In order to achieve the above object, a thread trimming apparatus for a button-attached sewing machine according to the present invention includes a button attaching step for forming a seam by a cooperative action of a vertical movement of a needle and a rotational movement of a looper to sew a button on a cloth. And / or after the end of the root winding process in which the needle-wrapping thread is wound around the buttoning thread and reinforced by alternately dropping needles at the left and right positions of the outer periphery of the buttoning thread. Needle on the side connected to the end of the buttoning thread and / or the root winding thread among the two needle thread parts that are stretched and held in a substantially triangular loop shape gradually narrowing toward the upper part between the looper and the looper A thread cutting device for a button-attached sewing machine having a knife mechanism for cutting a thread portion, wherein the knife mechanism is capable of reciprocating between a lower position of a needle plate and a side portion position of the needle plate. From the side position of the needle plate, under the needle plate When moving forward toward the position, the needle thread on the side that enters the substantially triangular loop space formed by the two needle thread sections and continues to the end of the buttoning thread and / or the root winding thread A fixed knife having a sharp needle thread hook guiding portion that hooks the portion and guides it to the blade edge, and the needle thread hook that is pivotally supported via a fulcrum shaft on the base end side of the fixed knife A movable knife that can be opened and closed by a sliding contact with the blade edge of the fixed knife by hooking on the guide edge and guiding the needle thread portion guided by the blade edge part. An actuator for reciprocating driving movement between the two positions, and when the knife mechanism is moved to near the end of the reciprocating driving movement path by the actuator, the movable knife is moved relative to the edge of the fixed knife. Around the fulcrum axis. The movable knife is slidably released from the edge of the fixed knife when the knife mechanism is moved backward by the actuator to the vicinity of the starting end of the reciprocating drive movement path. And a movable knife open / close swing control mechanism that opens and swings in the other direction around the fulcrum shaft.

  In the thread trimming apparatus for a button-attached sewing machine according to the present invention, the movable knife open / close swing control mechanism is a projecting piece portion integrally projecting from the proximal end portion of the movable knife to the side of the reciprocating path of the knife mechanism. And fixedly suspended downward from the needle plate near the end and near the start of the reciprocation path of the knife mechanism, and the projecting piece abuts to move the movable knife around the fulcrum axis in the one direction and the other direction. And a contact member that controls opening and closing and swinging.

  Further, in the thread trimming apparatus for a button-attached sewing machine according to the present invention, the knife mechanism is a fixed knife at a tip end of a swinging arm that is supported by the thread moving shaft so as to be swingable about the axis of the thread moving shaft. The movable knife is pivotally supported on the base end side of the fixed knife so as to be able to swing, and the swing arm is driven to swing around the axis of the yarn feeder shaft via the actuator. Accordingly, it is preferable that the entire knife mechanism is configured to be capable of reciprocating drive swinging between the two positions.

  Further, in the thread trimming apparatus for a button-attached sewing machine according to the present invention, the knife mechanism is configured to be capable of linearly reciprocating along the horizontal plane or substantially horizontal plane between the two positions via the actuator. Is preferred.

  Further, in the thread trimming device for a button-attached sewing machine according to the present invention, the fixed knife of the knife mechanism is attached to the tip of the swing arm so that the position thereof can be adjusted in the axial direction of the yarn feeder shaft. It is preferable.

  According to the thread trimming apparatus for a button sewing machine according to the present invention having the above-described characteristic configuration, after the buttoning process is completed and / or after the root winding process is completed, the entire knife mechanism is connected to the needle plate via the actuator. Is moved forward from the side portion position toward the lower position of the needle plate. As the knife mechanism moves forward, the needle thread hooking guide member of the fixed knife moves into a wide part below the substantially triangular loop space formed by the two needle thread parts, and is one of the sides to be cut. The needle thread portion of the book, that is, the needle thread portion on the side connected to the end portion of the buttoning thread and / or the root winding thread is captured and guided to the blade edge of the fixed knife. When the entire knife mechanism reaches near the end of the forward drive movement path, the movable knife is closed and swung in one direction around the fulcrum shaft on the proximal end side of the fixed knife through the swing control mechanism and fixed. The scissors act on the blade edge of the knife in the same manner as when the hand-held scissors are closed. Thereby, the needle thread portion guided to the edge of the fixed knife is cut at a narrow portion of the substantially triangular loop space. Therefore, only the needle thread portion on the side that needs to be cut can be surely cut into a state where the remaining thread length is short, and the appearance after the button is attached can be improved.

  In addition, the needle thread is cut by the sliding contact between the blade edges of the movable knife and fixed knife, not just by the movable knife, so that the knife is sharp and thin like a cutter blade. There is no need to use anything. For this reason, there is very little cutting or breakage of the blade, and a predetermined yarn cutting performance can be ensured even after continuous use over a long period of time.

In addition, the fixed knife and the movable knife are separated and attached to different locations such that the movable knife is pivotally supported via a fulcrum shaft on the base end side of the fixed knife, The needle mechanism guided between the two scalpels is squeezed out while reciprocating and moving the entire scalpel mechanism assembled so that the fixed scalpel and movable scalpel can be opened and closed. It is easy to adjust the blade edges of the knife to the proper rubbing performance at the assembly stage, and the adjusted proper rubbing performance is suppressed from decreasing with use for a long time. Thus, proper rubbing performance can be maintained.
Therefore, it is possible to keep the sharpness by the knife mechanism always good, the knife replacement and maintenance cycle can be extended for a very long time, the maintenance work can be reduced, and the running cost can be reduced. In spite of this, there is an effect that only a predetermined needle thread portion can be surely cut into a state in which the remaining thread length is short and looks good.

  In particular, the open / close swing control mechanism of the movable knife is composed of a projecting piece that is integrally projected from the movable knife and a contact member that is fixedly suspended downward from the needle plate. There is no need to use a special actuator for sliding contact and release. Therefore, the structure of the sewing machine bed that incorporates the knife mechanism is simplified, and the manufacturing cost of the entire thread trimming device is reduced. Can be achieved.

  Further, when the knife mechanism is configured to be capable of reciprocating drive movement between both the above-mentioned positions, the knife mechanism is supported so as to be swingable around the axis of the yarn gathering shaft provided inside the sewing machine bed portion. A fixed knife of the knife mechanism is attached to the tip of the swing arm, and the knife mechanism is configured to be capable of reciprocating drive swinging around the axis of the thread guide shaft. As a support member for stable reciprocating drive movement along a fixed path, an existing thread-shift shaft can be used effectively, thereby enabling a structure for incorporating a knife mechanism and stabilizing the operation. It can be simplified.

  In addition, when the knife mechanism is configured to be linearly reciprocatingly movable along the horizontal plane or the substantially horizontal plane between the two positions described above, the space required for the reciprocating movement of the female mechanism, particularly in the vertical direction The required space (thickness) can be kept to a minimum, which eliminates the need for special improvements such as increasing the size of the sewing machine bed to secure the installation space for the knife mechanism, and the overall production cost of the device It is easy to achieve further reduction and compactness.

  Furthermore, when attaching the fixed knife of the knife mechanism to the tip of the swinging arm that swings around the axis of the thread gathering shaft, it is possible to adjust the position in the axial direction of the thread gathering shaft. Even if the button thickness or thread thickness (count) is something like that, the needle thread part to be cut is surely captured, and the thread can be cut with a short thread remaining length. Can be done well.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic overall perspective view of a sewing machine with a root winding button showing an embodiment of the present invention. It is a disassembled perspective view of the whole thread trimming device which is the principal part of a sewing machine with a root winding button. It is a front view of the principal part which shows the assembly | attachment state of a thread trimming apparatus same as the above. (A), (b) is operation | movement explanatory drawing of the buttoning process by a root winding buttoning sewing machine same as the above. (A), (b) is operation | movement explanatory drawing of the root winding process by a root winding button attaching sewing machine same as the above. (A)-(f) is a figure explaining operation | movement of the rocking | fluctuation control mechanism of a movable knife. (A)-(d) is an expansion perspective view of the principal part explaining in order the yarn cutting operation by the thread trimming device of the root winding button sewing machine of embodiment. It is an expanded perspective view of the principal part which shows the state after thread | yarn cutting by the thread trimming apparatus after completion | finish of the root winding process by a root winding button attachment sewing machine same as the above.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic overall perspective view of a root winding button sewing machine showing an embodiment of the present invention. FIG. 2 is an exploded perspective view of the entire thread trimming apparatus, which is the main part of the above-described root winding button sewing machine. FIG. 3 is a front view of the main part showing the assembled state of the same thread trimming device. FIGS. 4A and 4B are operation explanatory views of the buttoning process by the root winding buttoning sewing machine. FIGS. 5A and 5B are operation explanatory views of the root winding process by the same root winding button attaching sewing machine.

  As shown in FIG. 1, the needle-wound button-equipped sewing machine 1 of the present embodiment is provided with a needle 3 that reciprocates up and down a fixed path via an elevating drive mechanism (not shown) provided in a sewing machine arm 2. In addition, a cloth W (see FIGS. 4 to 6 and 8) to which a button B (see FIGS. 4 to 6 and 8) is to be sewn is provided at the front part of the double-up and down movement path of the needle 3. The dough holder 4 for setting the needle 3 in the double-folded movement path in the folded state, the dough guide 5 for moving and guiding the set folded cloth W in the horizontal direction along the horizontal plane, and the button B are sandwiched from both sides in the radial direction. The button holder 6 to be held, the fabric presser 47 that presses the fabric W obliquely from above when the button is attached, and the needle thread that can be protruded and retracted with respect to the vertical movement path of the needle 3 and is thread-cut after the buttoning process is finished. Oblique part 12b (see FIG. 7) Wiper 7 such dispel rearward upward is configured is disposed. Since each of these components is well known, detailed description thereof will be omitted.

  A looper 9 reciprocally driven and rotated by a looper shaft 9A having an axis perpendicular to the double-up and down movement path of the needle 3 and a thread A cutting device 13 and a yarn moving shaft 33 are provided. As shown in FIG. 4B, the looper 9 is provided with a button for sewing the button B to the fabric W by forming a seam by the cooperative action of the vertical movement of the needle 3 and the rotational movement of the looper 9. As shown in FIG. 5 (b), the needles 3 are alternately placed on the left and right sides of the outer periphery of the buttoning thread 10 by the cooperative action of the needles 3 and the looper 9 after the buttoning process. A root winding process is performed in which the root winding thread 37 is wound around the buttoning thread 10 for reinforcement.

  After the buttoning process as shown in FIGS. 4 (a) and 4 (b), the thread trimming device 13 is formed in a substantially triangular loop shape with a gradually narrower width between the buttoning thread 10 and the looper 9. Of the two needle thread portions 12a and 12b that are stretched and held, the needle thread portion 12a that is connected to the end of the buttoning thread 10 and the root winding process as shown in FIGS. 5 (a) and 5 (b) Later, of the two needle thread portions 37a and 37b that are held in a substantially triangular loop shape gradually narrower toward the upper part between the root winding thread 37 and the looper 9, the end of the root winding thread 37 The needle thread portion 37a on the side continuous with the portion is cut.

  The thread trimmer 13 includes a knife mechanism 21 composed of a fixed knife 16 and a movable knife 14, and the knife mechanism 21 as a whole. An air cylinder 22 as an actuator that reciprocates and swings in the arrow direction xy in FIG. 3 between the lower position and the movable knife 14 of the knife mechanism 21 with respect to the blade edge 16a of the fixed knife 16. And a movable knife swinging control mechanism 23 for switching between a closed state in which the sliding contact is swung in the yarn cutting direction and an open state in which the blade edge portion 16a of the fixed knife 16 is released to swing in the non-cutting direction. .

  More specifically, as shown in FIGS. 2 and 3, the knife mechanism 21 includes a fixed knife 16 and a movable knife that is pivotally supported on the base end side of the fixed knife 16 via a fulcrum shaft 19. 14 and a spring 20 that elastically presses both the scalpels 16 and 14 from above and below to hold them in an elastic contact state, and can be opened and closed. When the entire scalpel mechanism 21 of the fixed scalpel 16 is swung in the direction of the arrow y in FIG. 3 from the lateral position of the needle plate 15 toward the lower position of the needle plate 15, the two needles are moved. It enters the substantially triangular loop space portion S formed by the thread portions 12a, 12b or 37a, 37b and hooks one of the needle thread portions 12a or 37a, and the edge 16a of the fixed knife 16 A needle thread hooking guide portion 16b having a sharp tip for sequentially moving and guiding is formed.

  The air cylinder 22 is disposed so as to protrude outward from the side of the sewing machine bed portion 8, and is supported by a mounting base 24 fixed to the extension portion 15 b of the needle plate 15 via screws 25. The movable rod 22a of the air cylinder 22 reciprocates linearly in the direction perpendicular to the axis of the looper shaft 9A and the yarn feeder shaft 33 outside the side of the sewing machine bed 8 as the air cylinder 22 expands and contracts. Moving.

A swing arm (female base) 26 that is swingable about the axis of the yarn gathering shaft 33 is pivotally supported on the yarn gathering shaft 33 disposed in the sewing machine bed 8. The swing arm 26 is formed with a long groove 27 penetrating between both side surfaces in the axial direction of the yarn gathering shaft 33.
Note that the middle portion of the two needle thread portions 12 a and 12 b that are stretched and held between the fabric W and the looper 9 are gathered together on the yarn gathering shaft 33 so as to be retracted from the vertical movement path of the needle 3. A yarn gathering tool (not shown) that reciprocally rotates around the axis of the yarn gathering shaft 33 is attached to the yarn gathering shaft 33. Since the structure and operation of this yarn gathering tool are well known, the detailed explanation and illustration thereof are shown. Is omitted.

  A knife support member 28 is fixedly connected to the tip of the movable rod 22 a of the air cylinder 22. This knife support member 28 is configured to be reciprocally slidable in the width direction of the sewing machine bed portion 8 along the lower surface of the extension portion 15b of the needle plate 15 as the air cylinder 22 expands and contracts. A pin 29 is inserted into a long groove 27 formed in the swing arm 26 so as to be relatively movable in the longitudinal direction of the long groove 27 at the distal end portion of the knife support member 28 located in the sewing machine bed portion 8. Is held.

  The fixed knife 16 of the knife mechanism 21 has a mounting plate portion 16c extending in a direction orthogonal to the blade edge portion 16a. The fixed knife 16 is attached to the tip end portion of the swing arm 26 via a long hole 16d formed in the attachment plate portion 16c and a fixing screw 30 so that the position of the yarn feeder shaft 23 can be adjusted. . With the above configuration, when the air cylinder 22 expands and contracts, the knife support member 28 linearly reciprocates and moves, and the reciprocating drive force of the knife support member 28 swings through the pin 29 and the long groove 27. The swing arm 26 is reciprocally driven and swung about the axis of the yarn gathering shaft 33 as a result of being transmitted to the moving arm 26, and the reciprocating drive swing of the swing arm 26 causes the entire female mechanism 21 to move to the needle plate. 15 is configured to be reciprocally driven and swingable between a side position of 15 and a position below the needle plate 15.

  Further, the movable knife 14 of the knife mechanism 21 is integrally formed with a projecting piece 14b that protrudes to the side of the reciprocating rocking path of the entire knife mechanism 21 so as to be substantially orthogonal to the blade edge 14a. On the other hand, a pair of contact members 31a and 31b are fixedly suspended downward from the lower surface of the needle plate 15 near the end and near the start of the reciprocating swing path of the knife mechanism 21, and these projecting pieces 14b The pair of contact members 31a and 31b constitute an open / close swing control mechanism 23 for the movable knife 14 in the knife mechanism 21.

  FIGS. 6A to 6F are diagrams for explaining the opening / closing operation by the opening / closing swing control mechanism 23 of the movable knife 14. In the open / close swing control mechanism 23 of the movable knife 14, one of the pair of contact members 31a and 31b is provided with one of the contact mechanisms 31a as shown in FIGS. 6 (a) and 6 (b). When the forward swing is made to near the end of the reciprocating drive swing path, the projecting piece 14b of the movable knife 14 comes into contact. After this contact, the knife mechanism 21 is further swung to the end of the reciprocating drive rocking path, so that the movable knife 14 is unidirectional around the fulcrum shaft 19 as shown in FIG. The blade edge portions 14a and 16a of both the knives 14 and 16 of the knife mechanism 21 are slidably brought into contact with each other and the needle thread portion 12a or 37a is cut (squeezed).

  Further, as shown in FIG. 6 (e), when the knife mechanism 21 is oscillated backward to the vicinity of the start end of the reciprocating drive oscillation path, the projecting portion of the movable knife 14 is placed on the other contact member 31b. 14b contacts. After this contact, the knife mechanism 21 is further swung to the starting end of the reciprocating drive swing path, so that the movable knife 14 moves in the other direction around the fulcrum shaft 19 as shown in FIG. The blade edge portions 14a and 16a of both the knives 14 and 16 of the knife mechanism 21 are slidably released from each other and returned to the next cutting standby state.

  Next, the buttoning process by the root winding buttoning sewing machine 1 according to the embodiment configured as described above and the buttoning operation in which the root winding process is one cycle, and after the buttoning process is completed and the root winding process The yarn cutting operation by the yarn trimming device 13 after the end of will be described.

  In the buttoning process immediately after the operation of the root winding button sewing machine 1, as shown in FIGS. 4A and 4B, the seam is formed by the cooperative action of the vertical movement of the needle 3 and the rotational movement of the looper 9. Form and sew the button B to the folded fabric W. Then, the operation of the thread trimming device 13 is started when the button attaching process with a predetermined number of stitches is completed.

  The yarn cutting operation of the yarn cutting device 13 is as shown in FIGS. That is, immediately after the end of the buttoning process, as shown in FIG. 7A, the needle thread portion 12 a on the side continuous with the end of the buttoning thread 10 is interposed between the buttoning thread 10 and the looper 9. The needle thread portion 12b inserted and held in the needle hole at the tip end of the needle 3 is held in a substantially triangular loop shape with a gradually narrower width toward the upper part, and the female mechanism 21 in the thread trimmer 13 is As shown in FIG. 6A, two needles in a substantially triangular loop shape formed below the needle plate 15 in an open state in which the blade edge portions 14a, 16a of both the scalpels 14, 16 are released from sliding contact with each other. It is waiting in the side part position of the thread portions 12a and 12b.

  Next, the air cylinder 22 is driven to extend, and the extension driving force of the movable rod 22a is transmitted to the swing arm 26 via the knife support member 28 and the pin 29, so that the swing arm 26 and the knife mechanism 21 are threaded. The forward drive is swung from the side portion position toward the lower position of the needle plate 15 around the axis of the shift shaft 33. Along with the forward drive swing of the knife mechanism 21, a sharp needle thread hooking guide member 16b of the fixed knife 16 is formed by two needle thread portions 12a and 12b as shown in FIG. 7B. One needle thread portion on the side to be cut by entering a wide portion below the substantially triangular loop space S, that is, the needle thread portion 12a on the side continuous with the end portion of the buttoning thread 10 is captured and captured. The needle thread portion 12a thus guided is guided to the blade edge portion 16a. Until this state is reached, as shown in FIGS. 6B and 6C, the fixed knife 16 and the movable knife 14 remain in an open state in which the blade edge portions 14a and 16a are released from sliding contact with each other.

  Next, when the knife mechanism 21 reaches near the end of the forward drive swing path, as shown in FIG. 6C, the projecting piece 14b of the movable knife 14 comes into contact with one of the contact members 31a. After the contact, the knife mechanism 21 is further swung to the end of the reciprocating drive swing path, so that the movable knife 14 is moved as shown in FIGS. 6 (d) and 7 (c). The blade edge portions 14a and 16a of both the scalpels 14 and 16 of the scalpel mechanism 21 are slidably contacted in one direction around the fulcrum shaft 19 so that the width of the substantially triangular loop space S is reached. The needle thread portion 12a is cut (squeezed) at a narrow portion.

  After that (after the yarn is cut), the air cylinder 22 is driven to contract, and the driving force is transmitted to the swing arm 26 by the movable rod 22a via the knife support member 28 and the pin 29, and the swing arm 26 is moved. As shown in FIG. 6 (d), the forward drive is swung from the lower position of the needle plate 15 toward the side part about the axis of the yarn moving shaft 33. As a result, the knife mechanism 21 is retracted from the needle thread portions 12a and 12b as shown in FIGS. 6 (e) and 7 (d). At this time, the other needle thread portion 12b cut off by the cutting is held by the wiper 7 and is dispelled to the rear side of the double forward and backward movement path of the needle 3.

  Next, when the knife mechanism 21 reaches the vicinity of the starting end of the forward drive swing path, the protruding piece 14b of the movable knife 14 comes into contact with the other contact member 31b. Then, after this contact, the knife mechanism 21 is further swung to the starting end of the forward drive swing path, so that the movable knife 14 is rotated around the fulcrum shaft 19 as shown in FIG. Thus, the swinging control is performed in the other direction, the blade edge portions 14a and 16a of both the scalpels 14 and 16 of the scalpel mechanism 21 are released from sliding contact, and are returned to the open state.

  Then, when the button attaching process and the thread cutting operation with the predetermined number of stitches are completed, the button holder 6 is turned by approximately 90 °, and the button B is switched to the vertical posture in the root winding process with respect to the fabric W. Move to the root winding process.

  In this root winding process, as shown in FIGS. 5 (a) and 5 (b), the needles 3 are alternately dropped to the left and right positions on the outer periphery of the buttoning thread 10, and cooperate with the rotational movement of the looper 9. The button thread 10 is reinforced by sequentially winding the root thread 37 around the button thread 10.

  When the root winding process with a predetermined number of stitches is completed, the thread trimming device 13 starts to operate again, and the needle thread portion 37a on the side connected to the end of the root winding thread 37 is fixed knife of the knife mechanism 21. 16 and the blade edge portions 16a of the movable knife 14 are cut by a sliding contact action between the blade edges 16a. The yarn cutting operation after the end of the root winding process is performed after the end of the buttoning process. Since it is performed in exactly the same manner as the yarn cutting operation, its detailed description and illustration are omitted.

  As described above, according to the thread trimming device 13 of the present invention, after the buttoning process and the root winding process are completed, the entire knife mechanism 21 is centered on the support shaft at the side portion of the needle plate 15. As the forward drive is swung toward the lower position of the plate 15, the needle thread hooking guide portion 16b of the fixed knife 16 of the knife mechanism 21 is formed by two needle thread portions 12a and 12b. One needle thread portion on the side to be cut by entering a wide portion below the loop space S, that is, the needle thread portion 12a on the side continuous with the end portions of the buttoning thread 10 and the root winding thread 37 is captured. Guide and guide to the edge 16a of the fixed knife 16. The needle thread portion 12a guided by the blade edge portion 16a is moved by the sliding movement of the movable knife 14 with respect to the blade edge portion 16a of the fixed knife 16 along with the forward drive swing of the knife mechanism 21. The space S is cut (squeezed) at a narrow portion. Therefore, it is possible to reliably cut only the needle thread portion 12a on the side that requires cutting without mistake.

  Further, for example, when viewed in the state after the root winding process, as shown in FIG. 8, only the needle thread portion 37 a on the side continuous to the end of the root winding thread 37 is exposed to a very short length on the surface of the fabric W. Since the thread is cut in a state, the yarn residue is hardly noticeable, and the appearance after the button is attached can be improved.

  Further, since the needle thread portions 12a and 37a are squeezed by the sliding action of the blade edges 14a, 16a of the movable knife 14 and the fixed knife 16 instead of being pushed only by the movable knife 14, the movable knife 14 As a result, it is not necessary to use a sharp thin-walled material such as a cutter blade. For this reason, there is very little cutting or breakage of the blade, and a predetermined yarn cutting performance can be ensured even after continuous use over a long period of time.

Further, the knife mechanism 21 pivotally supports the movable knife 14 on the base end side of the fixed knife 16 through the fulcrum shaft 19 so that the movable knife 14 can be opened and closed. Are separated from each other and attached to different locations, and the entire female mechanism 21 in which the fixed knife 16 and the movable knife 14 are assembled together is reciprocally driven and guided between both the knife 16 and 14. Since the needle thread portions 12a and 37a are cut off, the blade edges of both the scalpels 16 and 14 are properly slid together at the assembly stage of the scalpel mechanism 21 before being assembled into the sewing machine bed portion 8. It is possible to easily adjust the performance, and it is possible to maintain the proper sliding performance over a long period of time by suppressing the fall of the adjusted proper sliding performance with use. It is.
Accordingly, the sharpness by the knife mechanism 21 is always kept good, the movable knife 14 replacement and maintenance cycle can be extended for a very long time, the maintenance work can be reduced, and the running cost can be reduced. However, it is possible to cut only a predetermined needle thread portion with certainty and a good appearance with a short thread remaining length.

  In particular, as shown in the above-described embodiment, as the opening / closing swing control mechanism 23 of the movable knife 14, a pair of projecting pieces 14 b integrally projecting from the movable knife 14 and a pair of fixedly suspended downward from the needle plate 15. With the contact members 31a and 31b, it is not necessary to incorporate a special actuator or the like for the sliding contact and the sliding contact release of both the knife 14 and 16 in the knife mechanism 21, and the knife mechanism 21 is incorporated. The structure of the sewing machine bed portion 8 can be simplified and made compact, and the manufacturing cost of the entire thread trimming apparatus can be reduced.

  Further, as in the above-described embodiment, when the knife mechanism 21 is configured to be capable of reciprocating drive movement between the lateral position of the needle plate 15 and the lower position of the needle plate 15, Attach to the tip of a swing arm 26 that swings about the axis of the yarn gathering shaft 33 provided inside, and the reciprocating drive swings the entire knife mechanism 21 around the axis of the yarn gathering shaft 33. By making it possible, the existing thread shifting shaft 33 can be effectively used as a support member when the knife mechanism 21 is incorporated into the sewing machine bed portion 8, whereby the knife mechanism 21 can be incorporated and operated. The structure for stabilization can be further simplified.

  Further, by attaching the movable mechanism 26 to the swing arm 26 of the fixed knife 16 so that the position can be adjusted, the thread remaining length is short regardless of the thickness of the button B to be sewn or the thread count. Thread cutting can be performed at

In the above-described embodiment, the knife mechanism 21 is attached to the tip of the swing arm 26 that can freely swing around the axis of the yarn gathering shaft 33, and the knife mechanism 21 is attached to the shaft center of the yarn gathering shaft 33. Although the description has been given of the reciprocating drive swingable as the center, it is not limited to this.
For example, the knife mechanism 21 may be configured to be capable of linearly reciprocatingly moving along a horizontal plane or a substantially horizontal plane via an actuator such as a rotary cam in the sewing machine bed portion 8. In this case, it is possible to minimize the space required for reciprocating and moving the knife mechanism 21, particularly the required space in the vertical direction. No special improvement such as increasing the size of the portion 8 is required, and it is easy to further reduce the manufacturing cost of the entire apparatus and make it compact.

  Furthermore, in the above-described embodiment, the description has been given of the one in which the yarn cutting device 13 is operated to perform the yarn cutting operation after the buttoning step and the root winding step are completed. In the case of a non-button sewing machine, when the yarn cutting operation is performed only after the buttoning process is completed, the same operation as described above is performed and the same effect is achieved.

DESCRIPTION OF SYMBOLS 1 Root winding button sewing machine 3 Needle 9 Looper 10 Button attaching thread 12a, 12b Needle thread part 13 Thread trimming device 14 Movable knife 14a Blade edge part 14b Projection part 15 Needle plate 16 Fixed knife 16a Blade edge part 16b Needle thread hooking guide Part 19 fulcrum shaft 21 female mechanism 22 air cylinder (actuator)
23 Opening / closing swing control mechanism of movable knife 26 Swing arm 33 Yarn-feeding shaft 37 Neck wound thread B Button W Fabric S Loop space of substantially triangle

Claims (5)

The needle is alternately dropped at the left and right positions on the outer periphery of the buttoning thread after the buttoning process in which a stitch is formed and the button is sewn to the fabric by the cooperative action of the vertical movement of the needle and the rotational movement of the looper. After the root winding process, in which the root winding thread is wound around the buttoning thread and reinforced, the button winding thread and / or the root winding thread and the looper are spanned in a substantially triangular loop shape gradually narrowing toward the top. A thread cutting device for a button-attached sewing machine having a knife mechanism for cutting a needle thread portion connected to an end portion of a button attaching thread and / or a root winding thread among two held needle thread portions. ,
The knife mechanism is capable of reciprocating between a lower position of the needle plate and a lateral position of the needle plate, and when moving forward from a lateral position of the needle plate toward a lower position of the needle plate. , Entering a substantially triangular loop space portion formed by the two needle thread portions, hooking the needle thread portion on the side connected to the end portion of the buttoning thread and / or the root winding thread to the edge of the blade A fixed knife having a needle thread hooking guide portion having a sharp tip to be guided, and a blade edge portion which is pivotally supported on the base end side of the fixed knife through a fulcrum shaft and hooked on the needle thread hook guide portion. A movable knife that cuts the needle thread portion guided by the sliding contact with the blade edge of the fixed knife, and is configured to be openable and closable.
An actuator for reciprocally driving the entire knife mechanism between the two positions; and when the knife mechanism is moved forward to near the end of the reciprocating drive movement path by the actuator, the movable knife is moved to the fixed knife. When the knife mechanism is closed and swung in one direction around the fulcrum axis so as to be in sliding contact with the blade edge of the blade, and when the knife mechanism is moved backward to the vicinity of the start end of the reciprocating drive movement path by the actuator, A movable knife opening / closing swing control mechanism for opening and swinging the movable knife in the other direction around the fulcrum axis so as to release the sliding movement from the edge of the fixed knife. Sewing machine thread trimming device.   The movable knife open / close swing control mechanism includes: a projecting piece integrally projecting from the base end of the movable knife to the side of the reciprocation path of the knife mechanism; and the end of the reciprocation path of the knife mechanism; A contact member that is fixedly suspended downward from the throat plate near the start end and controls the opening and closing of the movable knife in the one direction and the other direction around the fulcrum shaft by the projecting piece abutting. The thread trimming device for a buttoned sewing machine according to claim 1.   In the knife mechanism, a fixed knife is attached to a tip end of a swing arm that is swingably supported on a thread guide shaft about the axis of the thread guide shaft, and a movable knife is installed on the base end side of the fixed knife. The swing mechanism is pivotally supported so that the swing arm is driven and swinged about the axis of the thread guide shaft via the actuator, so that the entire knife mechanism is spanned between the two positions. The thread trimming device for a buttoned sewing machine according to claim 1 or 2, wherein the thread trimming device is configured to be capable of swinging in a reciprocating manner.   3. The thread trimming apparatus for a button-attached sewing machine according to claim 1, wherein the knife mechanism is configured to be able to reciprocate linearly along a horizontal plane or a substantially horizontal plane between the two positions via the actuator.   The thread trimming device for a button-equipped sewing machine according to claim 3, wherein the fixed knife of the knife mechanism is attached to the tip of the swing arm so that the position of the knife can be adjusted in the axial direction of the yarn feeder shaft.

Images