JP2005192688A - Thread end processor for zigzag stitch sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize the withdrawal amount of a needle thread at the time of a thread end processing and to perform an appropriate thread end processing with less quality decline and needle thread loss even while appropriate stitch balancing thread tension is maintained at all times and prescribed zigzag stitches are surely formed regardless of the change of the thickness of a sewing cloth or the like at the time of normal sewing. <P>SOLUTION: In athe zigzag stitch sewing machine provided with a wiper for picking a needle thread end part suspended from a needle and moving it to the side after sewing and a needle thread cutting knife for cutting the needle thread end part near the upper surface of the sewing cloth, in the route of supplying the needle thread to the needle 8, a rotary disk type needle thread tension device 14, a pretension mechanism 15 for imparting tension to the delivery of the needle thread 13 beforehand and an auxiliary needle thread holding mechanism 16 capable of elastically holding the needle thread 13 on the upper side in a needle thread supply direction from the pretension mechanism 15 are provided. Also, an operation switching mechanism 26 for selectively switching the pretension mechanism 15 and the auxiliary needle thread holding mechanism 16 to an operation state is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a thread end processing device for a staggered sewing machine. Specifically, after the stitch is raised at the end of the staggered stitch by the zigzag stitching machine, it is cut below the sewing cloth, and then the end of the needle thread that is lowered from the needle is gripped by the needle thread gripper, This invention relates to a thread end processing device for a staggered sewing machine configured to cut a needle thread moved sideways by a knife near the upper surface of the sewing cloth at the start of sewing of the next sewing cloth. Is.

  In the staggered sewing machine, when the sewing thread that has been lowered from the needle at the end of sewing is left as it is and the sewing of the next sewing cloth is started, the end of the lowering needle thread moves to the lower side of the sewing cloth due to the downward movement of the needle. The needle thread is entangled with the stitches while the stitches for several stitches are advanced, and the end portions of the needle threads are entangled with the zigzag stitches to generate a so-called poor-quality stitch called a bird's nest. In order to prevent such deterioration in the quality of the seam at the start of sewing, a needle thread gripping tool that grips the end part of the needle thread that is lowered from the needle at the end of sewing and moves it to the side and the start of sewing for the next sewing cloth A zigzag stitching machine equipped with a thread end processing device consisting of a needle thread trimming knife that cuts the needle thread that has been gripped and moved sideways as the sewing progresses for several stitches near the upper surface of the sewing cloth has been known. (For example, refer to Patent Document 1).

  In staggered sewing machines, the needle thread in the middle of the needle thread supply path is wound around the outer peripheral surface for at least one turn as a thread tension to maintain the proper and smooth supply of the needle thread from the spool to the needle during normal sewing. Needle thread tension that has a disc that can be held and a spring that applies frictional torque to the rotation of the disc, and that can be fed out by applying a predetermined tension to the needle thread by the rotation of the disc accompanying the supply of the needle yarn linked to the sewing operation And a pretensioning mechanism that is provided on the upper side of the needle thread supply direction than the needle thread tensioner and pre-tensions the needle thread with respect to the feeding of the needle thread tensioner. (For example, see Patent Document 2).

  No. 5-32067   JP 10-21380 A

  As is clear from the above-mentioned conventional techniques, in the staggered sewing machine, the end of the needle thread that has been cut from the bottom of the sewing cloth at the end of sewing of one sewing cloth and then the needle thread is lowered by the needle thread gripper. Thread at the time of normal sewing is used for the needle thread feeding control at the time of thread end processing that is gripped and moved to the side of the sewing part and cut by the needle thread knife near the top surface of the next sewing cloth at the start of sewing. In general, the above-described needle thread tension device and pretensioning mechanism provided as a tension are used as they are, and in this case, the following problems have occurred.

  In other words, the pre-tension mechanism is for pre-tensioning the needle thread so that there is no slip phenomenon that prevents the disk of the needle thread tensioner from rotating during normal sewing. When the tension by the needle thread tensioner is adjusted according to the flexibility, etc., the pretension is also adjusted in accordance with the adjustment, so that regardless of changes in the thickness of the sewing fabric or the flexibility of the fabric structure, It is configured to maintain the proper thread tension during normal sewing.

  As described above, the conventional pre-tensioning mechanism can adjust (set) the pre-tension within a certain range with the main purpose of maintaining the proper thread tension during normal sewing. If the tension mechanism is used as it is for controlling the feeding out of the needle thread at the time of the yarn end processing, the amount of needle thread brought out due to the lateral movement of the needle thread gripping tool may not be stable. In other words, when the pretension mechanism set in consideration of the thread tension during normal sewing is strong, the needle thread gripper grips the end part of the needle thread and moves to the side for thread end processing. When the needle thread is pulled out from the needle thread gripper and the end portion of the needle thread cannot be pulled out to the side, the end part of the needle thread is placed between the next sewing cloth and the presser foot. If the pretensioning mechanism has a weak pretension, there is a problem that a low quality seam in the shape of a bird's nest will be formed at the sewing start part of the next sewing cloth. As the needle thread gripper moves sideways, the needle thread is unwound excessively, and as a result, the length of the needle thread to be cut increases and the needle thread loss increases accordingly. there were.

  The present invention has been made in view of the above-described circumstances, and at the time of normal sewing, regardless of changes in the thickness of the sewing fabric, the flexibility of the fabric structure, etc., it is always possible to maintain a proper thread tone and to ensure a predetermined staggered stitch. Although it can be formed, the amount of needle thread taken out at the time of yarn end processing is stabilized, so that low-quality seams like bird's nests are not generated, and proper yarn end processing with little needle thread loss is performed. An object of the present invention is to provide a thread end processing device for a staggered sewing machine that can be performed.

  In order to achieve the above object, a thread end processing device for a staggered sewing machine according to the present invention is provided with a balance mechanism, a cloth feed mechanism, and a needle imitation mechanism that rotate in synchronization with the rotation of the main spindle of the sewing machine to form a staggered stitch. And a disk capable of winding and holding the needle thread in the middle of the needle thread supply path to the needle around the outer peripheral surface part for at least one turn and a spring for applying friction torque to the rotation of the disk. A needle thread tensioner that can be fed out by applying a predetermined tension to the needle thread by rotating the disk associated with the needle thread supply linked to the sewing operation, and on the upper side of the needle thread supply direction than the needle thread tensioner. A pre-tensioning mechanism that applies tension to the needle thread in advance with respect to the feeding of the needle thread tensioner, and an end portion of the needle thread that is lowered from the needle at the end of sewing, and the end portion of the grasped needle thread Is moved to the side of the sewing part. A staggered sewing machine provided with a needle thread gripper and a needle thread trimming knife that cuts the needle thread that is gripped by the needle thread gripper and moved to the side of the sewing part near the upper surface of the cloth to be sewn. In this yarn end processing apparatus, an auxiliary needle thread holding mechanism capable of elastically holding the needle thread in the needle thread supply path is provided on the upper side in the needle thread supply direction than the pretension mechanism. While the elastic holding of the needle thread by the thread holding mechanism is released, the normal sewing operation state in which the pretensioning mechanism applies pretension to the needle thread and the pretensioning mechanism by the pretensioning mechanism is released, while the auxiliary needle thread holding An action switching mechanism that can be switched to the action state of the needle thread end processing for elastically holding the needle thread by the mechanism is provided.

  According to the thread end processing device of the staggered sewing machine according to the present invention having the above-described configuration, during normal sewing, the operation switching mechanism is switched to the normal sewing operating state so that the thickness of the sewing fabric, the flexibility of the fabric structure, etc. Correspondingly, by adjusting the tension of the needle thread by the needle thread tension device and adjusting the pre-tension by the pre-tension mechanism accordingly, the thickness of the sewing cloth and the flexibility of the fabric structure can always be maintained while maintaining the proper thread tension. Regardless of changes in sex and the like, a predetermined zigzag stitch can be reliably and satisfactorily formed. Nevertheless, at the time of the needle thread gripping operation by the needle thread gripper after the sewing for one sewing cloth is finished, the action switching mechanism is switched to the action state of the needle thread end processing to release the pretensioning by the pretension mechanism. By holding the needle thread elastically with the auxiliary needle thread holding mechanism, the needle thread in the needle thread supply path is changed to a needle thread holding force suitable for thread end processing, and the amount of needle thread taken out at the time of thread end processing is changed. Can be stabilized. As a result, the needle thread end part comes out of the needle thread gripper and remains between the next sewing cloth and the presser foot to form a poor quality seam like a bird's nest, or the needle thread is excessively fed and cut. This prevents the needle thread length from becoming too long and the loss of discarded needle thread from increasing, and ensures that proper thread end processing is always performed regardless of the thread tension during normal sewing. There is an effect that can be done.

  In the thread end processing device for a staggered sewing machine according to the present invention, the pretensioning force applied to the needle thread by the pretensioning mechanism and the elastic holding force to the needle thread by the auxiliary needle thread holding mechanism can be adjusted, respectively. With this construction, the adjustment range of the thread tension at the time of normal sewing and the adjustment range of the needle thread holding force at the time of thread end processing can be made sufficiently wide, and a wide range of sewing with different thicknesses, flexibility of the structure, etc. Appropriate zigzag stitching and yarn end processing can always be performed on the fabric.

  Further, in the thread end processing device for the staggered sewing machine according to the present invention, the auxiliary needle thread holding mechanism and the pretensioning mechanism may be independently attached to the sewing machine arm. The auxiliary needle thread holding mechanism and the action switching mechanism for switching the operating state of the auxiliary needle thread holding mechanism and the pretension mechanism may be integrally mounted on a yarn path base for attaching the pretension mechanism to a sewing machine arm. desirable. In this case, the auxiliary needle thread holding mechanism and the action switching mechanism can be attached to the sewing machine arm using the existing attachment part provided in the conventional zigzag sewing machine for attaching the pretensioning mechanism. The needle thread flow path (supply path) need not be changed much, and the above-described effects can be achieved while the needle thread supply action is always kept smooth.

  Further, the needle thread trimming knife may be provided at a position near the upper surface of the sewing cloth. However, as described in claim 4, the needle thread trimming knife intersects with the needle drop groove of the presser foot, In the case of fixing to the lower surface, the cutting process can be performed with a short length without leaving the needle thread end that causes the quality of the sewing product to deteriorate.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an external perspective view showing the entire zigzag sewing machine according to the present invention, and FIG. 2 is an enlarged perspective view of an essential part thereof. The zigzag sewing machine 1 is a main shaft (not shown) provided in a sewing machine arm 2. A balance mechanism 5 comprising a rotating disk 3 that rotates in synchronization with the rotation of the rotating disk 3 and a balance 4 fixed to the rotating disk 3 is formed in the front surface of the sewing machine arm 2 and has a concave opening 2A with an opening / closing guard 6. The needle 8 is attached to the lower end of the needle bar 7 which is provided in the main shaft and linked to the main shaft via a crank mechanism (not shown), and the presser foot 9 has a cloth presser 10 is attached. The sewing machine arm 2 is provided with a needle swinging mechanism for forming a staggered stitch, and a lower part of a needle plate 12 provided on the sewing machine bed 11 has a thread trimming device, a cloth feeding mechanism, Although a shuttle mechanism and the like are provided, since these are well known, illustration and description of their specific structures are omitted. In FIG. 1, 30 is a lower thread winding device, and 31 is a lower thread winding pretension mechanism.

  The lower end of the sewing machine arm 2 is configured so that it can be driven to swing around a needle thread gripping shaft 29 supported by a needle thread gripping base 28 fixed to the sewing machine arm 2 via an air cylinder (not shown). When the needle 8 is lifted at the end, the thread trimming device cuts the lower portion of the sewing cloth, and then hooks the end portion of the needle thread 13 that is lowered from the needle 8, and the hooked needle thread end portion is sewn to the sewing portion (needle). A needle thread gripper (hereinafter referred to as a wiper) 21 that is moved to the side of the plate 12) and a needle thread end portion that is hooked on the wiper 21 and moved to the side are sandwiched and held between the wiper 21. An auxiliary needle thread grip 27 is provided. Further, on the lower surface of the cloth presser 10, a needle thread trimmer for cutting the needle thread end portion 13a, which is gripped by the wiper 21 and moved laterally at the start of sewing of the next sewing cloth, near the upper surface of the sewing cloth. A knife 22 is fixed so as to cross the needle drop groove 10a of the presser foot 10.

  On the other hand, on the side of the sewing machine arm 2, the feeding of the needle thread 13 in the needle thread supply path from the unillustrated thread winding to the needle 8 through the stationary thread guides 17 and 18 and the balance 4 of the balance mechanism 5 is controlled. As shown in FIG. 3, as the thread tension for this purpose, the rotary needle thread tensioner 14 and the rotary needle thread tensioner 14 on the upper side in the needle thread supply direction than the needle thread tensioner 14 are used. A pretensioning mechanism 15 that applies tension to the feeding in advance, and the needle thread 13 can be elastically held during gripping movement and cutting processing of a needle thread end portion, which will be described later, on the upper side of the pretensioning mechanism 15 in the needle thread supply direction. An auxiliary needle thread holding mechanism 16 is provided.

  The rotary needle thread tensioner 14 has a rotating disk 14A capable of winding and holding the needle thread 13 for one or more rotations on the outer peripheral surface thereof, a spring 14B that presses the disk 14A and applies friction torque to the rotation, and the spring. 14B includes a thread tension nut 14C for adjusting the disk pressing force by 14B, and applies a predetermined tension to the needle thread 13 by the rotation of the disk 14A accompanying the supply of the needle thread linked to the sewing operation. The pretension mechanism 15 includes two tone plates 15A and 15A, a spring 15B that presses the tone plates 15A and 15A, and a knob 15C that adjusts the pressing force of the spring 15B. A pretension is applied to the needle thread 13 by passing the needle thread 13 between 15A and 15A.

  Similar to the pretension mechanism 15, the auxiliary needle thread holding mechanism 16 adjusts the two tension plates 16A and 16A, the spring 16B that presses the tension plates 16A and 16A, and the pressing force of the spring 16B. 16C, and the needle thread 13 is elastically held by passing the needle thread 13 between the two tone plates 16A, 16A. The auxiliary needle thread holding mechanism 16 and the needle thread 13 are A yarn hooking pin 19 for guiding the pretensioning mechanism 15 is integrally attached to a yarn path 20 for attaching the pretensioning mechanism 15 to the sewing machine arm 2.

  Further, the thread guide base 20 includes a thread loosening plate 24 that can swing around a support shaft 23 at a substantially central portion between the pretension mechanism 15 and the auxiliary needle thread holding mechanism 16, and the thread loosening plate 24. And an air cylinder 25 that reciprocally swings the yarn loosening plate 24 through the air cylinder 25, and the two end plates 24a and 24b of the two tension plates 15A and 15A of the pretension mechanism 15 and By selectively fitting between the two tension plates 16A and 16A of the auxiliary needle thread holding mechanism 16, the elastic holding of the needle thread 13 by the auxiliary needle thread holding mechanism 16 is released, while the pretension mechanism 15 releases the needle thread. The operation state of normal sewing for applying a pretension to the roller 13 and the yarn end processing for elastically holding the needle thread 13 by the auxiliary needle thread holding mechanism 16 while releasing the pretensioning by the pretension mechanism 15 are released. Switchable action switching mechanism 26 is equipped to the use state.

  In the zigzag sewing machine configured as described above, when normal zigzag stitching is performed, the thread loosening plate 24 of the action switching mechanism 26 is swung in the direction of arrow a about the support shaft 23 to The elastic holding of the needle thread 13 by the auxiliary needle thread holding mechanism 16 is canceled by switching to the normal sewing operation state in which the one end plate portion 24b is fitted between the two tension plates 16A and 16A of the auxiliary needle thread holding mechanism 16. On the other hand, the pretensioning mechanism 15 adjusts the pretension by the pretension mechanism 15 according to the needle thread tension by the needle thread tensioner 15 that is adjusted in accordance with the thickness of the sewing cloth, the softness of the cloth structure, and the like. As a result, it is possible to reliably and satisfactorily form a predetermined zigzag stitch regardless of changes in the thickness of the sewing fabric, the flexibility of the fabric structure, etc. while maintaining an appropriate thread tension.

  Then, after the sewing for one sewing cloth is completed and the needle 8 is raised, the thread trimming device cuts the sewing thread under the sewing cloth and then cuts the needle thread end portion 13a that is lowered from the needle 8. Then, the thread loosening plate 24 of the action switching mechanism 26 is swung in the direction of the arrow b about the support shaft 23 so that the one end plate portion 24a of the thread loosening plate 24 is between the two tension plates 15A, 15A of the pretension mechanism 15. By switching to the applied state of the thread end processing, the pretension mechanism 15 releases the pretension, while the auxiliary needle thread holding mechanism 16 elastically holds the needle thread 13.

  In this state, the needle thread end portion 13a where the wiper 21 is actuated and is lowered from the needle 8 is hooked by the wiper 21 and moved to the side as shown in FIG. Then, the next sewing cloth W is set under the presser foot 10 and sewing for the next sewing cloth W is started as shown in FIG. Then, when the sewing further proceeds from the state of FIG. 6 in which the stitching for several stitches has progressed, it is hooked and moved to the side by the wiper 21 and held between the wiper 21 and the auxiliary needle thread grip 27. The needle thread end portion 13a touches the blade edge of the needle thread knife 22 fixed to the lower surface of the presser foot 10, and is cut as shown in FIG. The needle thread end portion 13a after the cutting is released from the auxiliary needle thread grip 27 when the wiper 21 is operated, and is collected and discarded in the bag, for example, by sucking air.

  At the time of yarn end processing as described above, the needle thread 13 in the needle thread supply path is inserted between the two tension plates 16A and 16A of the auxiliary needle thread holding mechanism 16 so that the needle thread holding force suitable for the thread end processing is obtained. Since the amount of the needle thread 13 taken out by the wiper 21 is stabilized, the needle thread end portion 13a comes out of the wiper 21 and remains between the next sewing cloth W and the presser foot 10 and the bird. Forming a seam with poor quality of the nest, or excessively extending the length of the needle thread where the needle thread 13 is excessively fed and cut, resulting in an increase in discarded needle thread loss. Thus, proper thread end processing can always be performed regardless of the thread tension during normal sewing.

  In the above-described embodiment, the auxiliary needle thread holding mechanism 16 and the action switching mechanism 26 are shown as being integrally provided on the thread guide base 20 for attaching the pretension mechanism 15 to the sewing machine arm 2. The auxiliary needle thread holding mechanism 16 and the action switching mechanism 26 may be mounted on the sewing machine arm 2 by being mounted on a thread path base different from the thread path base 20.

  In the above embodiment, the needle thread knife 22 is fixed to the lower surface of the presser foot 10, but may be fixed to the upper surface of the presser foot 10.

  Moreover, in the said embodiment, the wiper 21 which hooks the needle thread end part 13a keeps hold | maintaining between the auxiliary needle thread grips 27 until the hooked needle thread end part 13a is cut | disconnected by the needle thread knife 22. FIG. However, the needle thread end portion that is hooked by the wiper 21 and moved to the side may be held until it is cut by the wiper 21 alone.

  Furthermore, in the above-described embodiment, the description has been given of the case where the both end plate portions 24a and 24b of the thread loosening plate 24 in the action switching mechanism 26 are integrally formed. By making the fitting depth between the plates 15A, 15A and 16A, 16A adjustable, the pretension and the needle thread holding force can be finely adjusted.

  1 is an external perspective view showing an entire staggered sewing machine according to the present invention.   It is a perspective view of the principal part of a staggered sewing machine same as the above.   It is an expansion perspective view of the principal part of a staggered sewing machine same as the above.   It is a perspective view of the principal part explaining the initial action state among the processing conditions of the needle thread end part by the same staggered sewing machine.   It is a perspective view of the principal part explaining the 2nd action state among the processing conditions of a needle thread end same as the above.   It is a perspective view of the principal part explaining the 3rd action state among the processing conditions of a needle thread end part same as the above.   It is a perspective view of the principal part explaining the final action state among the processing conditions of the needle thread end same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Staggered sewing machine 2 Sewing machine arm 5 Balance mechanism 8 Needle 10 Work clamp 12 Needle plate 13 Needle thread 13a Needle thread end part 14 Needle thread tensioner 14A Disk 14B Spring 15 Pretension mechanism 15A Tension plate 15B Spring 16 Auxiliary needle thread holding mechanism 16A Conditioning plate 16B Spring 20 Yarn way 21 Needle thread gripper (wiper)
22 Needle thread knife 26 Action switching mechanism

Claims (4)

A balance mechanism that rotates in synchronization with the rotation of the sewing machine spindle, a cloth feed mechanism, and a needle swing mechanism are provided to form a staggered seam. A disk that can be wound and held for at least one rotation and a spring that applies friction torque to the rotation of the disk, and a predetermined tension is applied to the needle thread by the rotation of the disk accompanying the supply of the needle thread linked to the sewing operation. A needle thread tensioner that can be fed out, and a tension that is provided on the upper side of the needle thread supply direction from the needle thread tensioner so that slippage does not occur when the needle thread tensioner is fed. Grab the pre-tensioning mechanism, the end of the needle thread that is lowered from the needle at the end of sewing, and move the end of the sewn needle thread to the side of the sewing part. To the side of the sewing part In the yarn end processing apparatus zigzag sewing machine and thread cutting knife for cutting the needle thread end portions are dynamic near the upper surface of the sewing cloth, is provided,
An auxiliary needle thread holding mechanism capable of elastically holding the needle thread in the needle thread supply path is provided on the upper side of the needle thread supply direction than the pretension mechanism, and the needle thread by the auxiliary needle thread holding mechanism is provided. While releasing the elastic holding, the pre-tensioning mechanism applies a pre-tensioning mechanism to the needle thread and the pre-tensioning mechanism releases the pre-tensioning application, while the auxiliary needle thread holding mechanism makes the needle thread elastic. A thread end processing device for a zigzag stitch sewing machine, wherein an action switching mechanism capable of switching between an action state of a needle thread end portion to be held is provided.   The staggered sewing machine thread end processing device according to claim 1, wherein an application pretension to the needle thread by the pretensioning mechanism and an elastic holding force to the needle thread by the auxiliary needle thread holding mechanism are adjustable.   The auxiliary needle thread holding mechanism and an action switching mechanism for switching the operating state of the auxiliary needle thread holding mechanism and the pretension mechanism are integrally mounted on a yarn path base for attaching the pretension mechanism to a sewing machine frame. A thread end processing device for a staggered sewing machine according to claim 1 or 2.   The thread end treatment device for a staggered sewing machine according to any one of claims 1 to 3, wherein the needle thread trimming knife is fixed to the presser foot so as to intersect with a needle drop groove of the presser foot.

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