JP2010188106A - Thread cutter for button sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thread cutter for a button sewing machine which suppresses deterioration of sharpness, such as nicked edge, and increases the length of a replacement cycle to have reduced trouble and reduced running cost, and further reliably cuts only a predetermined part of a needle thread into a good appearance with reduced remaining length of the thread. <P>SOLUTION: After a button sewing step and/or a wound thread shank step, a movable knife 14 is driven to swing from a position on the side of the needle plate 15 to a position under the needle plate 15. A needle thread guide member 14A extends diagonally forward and downward from the movable knife 14, the needle thread guide member raises and guides only a part 12a of the needle thread on the side extending to the end of a button sewing thread 10 and/or a wound thread shank thread 37, relatively upward, out of two parts 12a and 12b of the needle thread extending between the button sewing thread 10 and/or the wound thread shank thread 37 and a looper 9 into a substantially triangular loop form. The raised and guided part 12a of the thread needle is cut by slide contact action between the movable knife 14 and a fixed knife 16 formed on the needle plate 15. <P>COPYRIGHT: (C)2010,JPO&INPIT

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 movable knife for cutting a needle thread portion connected to an end portion of a buttoning thread and / or a root winding thread, out of 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 thin movable knife such as a cutter blade is linearly reciprocated along a horizontal plane below a needle plate having a needle drop portion, so that a substantially triangular shape is obtained. Of the two needle thread portions that are stretched and held in a loop, the needle thread portion connected to the end portion of the buttoning thread and / or the root winding thread is pushed only by the movable knife. (For example, refer nonpatent literature 1).

  For example, referring to FIG. 9, the operation of cutting the needle thread portion after the end of the buttoning process by the above-described conventional button cutting machine thread trimming apparatus will be described in detail with reference to FIG. A state immediately after the end of the buttoning process in which the seam is formed by the cooperative action of the vertical movement of the looper and the rotational movement of the looper 42 and the button B is sewn to the fabric W is shown. At this time, between the buttoning thread 43 and the looper 42, there are a needle thread part 43a on the side continuous with the end part of the buttoning thread 43 and a needle thread part 43b inserted and held in the needle hole at the tip of the needle 41. However, the upper part is held in a substantially triangular loop shape gradually narrower toward the upper part, and has a needle drop part (not shown) on the horizontal plane at the lower part of the needle plate 44 that sets the fabric W in the needle drop part. A movable knife 45 that is configured to be linearly reciprocally movable along the line is waiting at a lateral position of the two needle thread portions 43a and 43b having a substantially triangular loop shape.

  Next, as shown in FIG. 9B, the movable knife 45 is linearly driven in the direction of the arrow x along the horizontal plane to move to the end of the buttoning thread 43. Next, as shown in FIG. 9 (c), the movable knife 45 is moved forward to a position directly below the needle plate 44 to push and cut the needle thread portion 43a. . Thereafter (after thread trimming), as shown in FIG. 9 (d), the movable knife 45 is linearly driven back in the direction of the arrow y along the horizontal plane, while the other needle thread portion. 43b is held by a wiper (not shown) and is dispelled to the rear side of the vertical movement path of the needle 41. In addition, since the thread trimming operation after the end of the root winding process is performed in the same manner as the thread trimming operation after the end of the above buttoning process, detailed description and illustration thereof are omitted.

  On November 1, 2004, Yamato Sewing Machine Manufacturing Co., Ltd. has a parts list "ILLUSTRATED SPARE PARTS LIST FOR ELECTRONIC CONTROLLED POSTED SEWER, MODELS NB3000 NB3100 No. 2", p. 10

  However, since the above-described conventional thread trimming device pushes and cuts the needle thread portion 43a with only the movable knife 45, in order to exert a good sharpness, the sharp movable knife with a sharp edge like a cutter blade is used. 45 must be used. For this reason, the sharpness of the knife 45 is likely to decrease rapidly due to a sharp edge or breakage of the knife 45 due to short-term use, and the needle thread portion 43a to be cut is directly below the needle plate 44 as the sharpness decreases. And the cutting position is shifted to a position away from the end of the buttoning thread 43. As a result, the remaining thread length becomes longer. For example, when viewed in the state after the root winding process, FIG. As shown, the needle thread portion 46a on the side connected to the end portion of the root winding thread 46 is exposed for a long time on the surface of the fabric W, so that the appearance tends to deteriorate. In order to avoid such a deterioration in appearance due to the reduction in sharpness, the movable knife 45 must be frequently replaced in a short use cycle, which is very troublesome and has a running cost. There is a problem of rising.

  In addition, the reciprocating drive movement path of the movable knife 45 is set as close as possible to the lower surface of the needle plate 44 so that the remaining thread length is shortened. The thin movable knife 45 pushes and cuts the narrow portion of the upper part of the loop of the two needle thread portions 43a and 43b that are held in a substantially triangular loop shape. As a result, the thin movable knife 45 is inserted and held in the needle hole. The two needle thread portions that form a loop, including the needle thread portion 43b that does not require cutting, are likely to be cut together. In order to avoid such inconvenience, generally, the reciprocating drive movement path of the movable knife 45 has been set at a position sufficiently spaced from the lower surface of the needle plate 36, and as a result, the yarn remainder The problem that the length became long and the appearance after the button was attached was unavoidable.

  The present invention has been made in view of the above-mentioned circumstances, and not only can reduce the sharpness such as cutting of the blade as much as possible to prolong the replacement cycle but also reduce troublesome labor and running cost. It is an object of the present invention to provide a thread trimming device for a button-attached sewing machine that can cut only a portion reliably and in a state where the remaining thread length is short and looks good.

  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. Of the two needle thread portions that are stretched and held in a substantially triangular loop shape that gradually narrows toward the top, between the looper and the looper, on the side that is connected to the end of the buttoning thread and / or the root winding thread A thread trimming device for a button-attached sewing machine having a movable knife that cuts a needle thread portion, the movable knife having a needle drop portion on a side portion of a needle plate that sets a cloth on the needle drop portion. The needle around the provided spindle Between the lower position of the needle plate and the side position of the needle plate so as to be reciprocally driven and swingable along a horizontal plane. When the forward drive swings toward the lower position of the plate, it enters into a wide portion below the substantially triangular loop space formed by the two needle thread portions, and along the horizontal surface of the movable knife after the entry. Further, the needle thread guide member having a sharp tip that travels upward and guides the needle thread portion connected to the end portion of the buttoning thread and / or the root winding thread in accordance with the forward drive swinging travels from the movable knife. A fixed knife that cuts the needle thread portion that is guided to be pulled up by a sliding action with a movable knife is integrally formed extending diagonally forward and downward in the swinging direction. It is characterized by being.

  In the thread trimming device for a button-attached sewing machine according to the present invention, the movable knife is formed in a substantially U shape in plan view, and the needle thread guide member is obliquely forward and downward from one side of the U shape. It is preferable to extend integrally.

  In the thread trimming apparatus for a button-attached sewing machine according to the present invention, it is preferable that the movable knife is configured such that its reciprocating swing movement path can be adjusted in the vertical direction.

  According to the thread trimming apparatus for a button sewing machine according to the present invention having the above-described characteristic configuration, the movable knife is supported on the side portion of the needle plate after the buttoning process and / or the root winding process. The needle drive guide swings forwardly toward the lower position of the needle plate with the center of the needle plate extending sharply forward and downward as the movable knife moves forward. One needle thread part on the side to be cut by entering a wide part below the substantially triangular loop space where the member is formed by two needle thread parts, that is, the end of the buttoning thread and / or the root winding thread The needle thread portion on the side connected to the needle portion is reliably captured, and the needle thread portion captured by the needle thread guide member with the subsequent forward movement of the movable knife moves relatively along the inclined side of the needle thread guide member. The guide is pulled up to the movable knife and guided to the movable knife. So that the needle thread portion of the narrow portion of the loop spaces of said generally triangular by sliding action between the fixed knife that is formed closest point to the dough is cut. Therefore, it is possible to cut only the needle thread portion on the side that requires cutting without fail, and in a state where the remaining thread length is short, so that the appearance after the button is attached can be improved.

  In addition, the movable knife is cut by the sliding contact with the fixed knife formed at the fixed position of the needle plate, not by the push-cut with only the movable knife. Since there is no need to use a thread, there is very little edge breakage or breakage, and a predetermined thread cutting performance can be ensured even when used continuously over a long period of time. Therefore, the replacement and maintenance cycle for keeping the sharpness of the movable knife always good can be extended for a very long time, and the maintenance work can be reduced and the running cost can be reduced. .

  In particular, by using a movable knife which is formed in a substantially U shape in plan view and the needle thread guide member is integrally extended from one side of the U shape, it is captured by the needle thread guide member and pulled up. The needle thread portion thus made can be surely locked and held at a fixed position, and the yarn can be cut reliably with a short yarn remaining length.

  In addition, by allowing the movable knife's swing movement path to be adjusted up and down according to the thickness of the button to be sewn, the thread remaining length can be adjusted regardless of the thickness of the button to be sewn. Yarn cutting in a short state can be performed reliably and satisfactorily.

1 is a schematic overall perspective view of a root winding button sewing machine showing a first embodiment of the present invention; It is a disassembled perspective view of the whole thread trimming device which is the principal part of the root winding button sewing machine which concerns on 1st Embodiment of this invention. (A), (b) is operation | movement explanatory drawing of the buttoning process by the root winding buttoning sewing machine which concerns on 1st Embodiment of this invention. (A)-(d) is an expansion perspective view of the principal part explaining in order the thread cutting operation by the thread trimming device which is the principal part of the root winding button sewing machine concerning a 1st embodiment of the present invention. (A), (b) is operation | movement explanatory drawing of the root winding process by the root winding button sewing machine which concerns on 1st Embodiment of this invention. It is an expansion 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 the root winding button attachment sewing machine which concerns on 1st Embodiment of this invention. It is an expansion disassembled perspective view of the attachment part of the thread trimming device which is the principal part of the root winding button sewing machine which concerns on 2nd Embodiment of this invention. It is an enlarged partial notch side view of the attachment part of the thread trimming device which is the principal part of the root winding button sewing machine which concerns on 2nd Embodiment of this invention. (A)-(d) is an expanded perspective view of the principal part explaining in order the yarn cutting operation | movement by the thread trimming apparatus of the conventional root winding button sewing machine. 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 the conventional root winding button sewing machine.

Hereinafter, a first embodiment 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-attached sewing machine shown in the first embodiment of the present invention, and FIG. 2 is an exploded perspective view of the entire thread trimming apparatus that is a main part of the root-winding button-attached sewing machine. The needle-wound button-equipped sewing machine 1 is provided with a needle 3 that reciprocates up and down at a fixed position via an elevating drive mechanism provided in the sewing machine arm 2 and at the front part of the vertical movement path of the needle 3. The cloth holder 4 for setting the cloth W (see FIGS. 3 to 6) to which the button B (see FIGS. 3 to 6) is to be sewn in the folded state to the vertical movement path of the needle 3; A cloth guide 5 for moving and guiding the cloth W in the horizontal direction along the horizontal plane, a button holder 6 for holding and holding the button B from both sides in the radial direction, a cloth presser 47 for pressing the cloth W obliquely from above when the button is attached, and the needle A wiper 7 and the like that can project and retreat with respect to the up and down movement path 3 and can dispose of the needle thread portion 35b after thread trimming obliquely rearward and upward after the buttoning process is completed. Since each of these components is well known, detailed description thereof will be omitted.

  Further, a button for sewing the button B to the fabric W by forming a seam in the sewing machine bed 8 by the cooperative action of the vertical movement of the needle 3 and the rotational movement of the looper 9 (see FIGS. 3 to 5). As shown in FIGS. 5 and 6, after the end of the attaching process and as shown in FIG. 5 and FIG. Of the two needle thread portions 12a and 12b that are stretched between the buttoning thread 10 and the root winding thread 37 and the looper 9 and are held in a substantially triangular loop shape gradually narrowing toward the upper part after the process is completed. A thread trimming device 13 for cutting 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 provided.

  The thread trimming device 13 includes a movable knife 14 and a fixed knife 16 formed on a needle plate 15 which is fixed to the lower surface of the central portion of the fabric guide 5 and has a needle drop portion for setting the fabric W. A specific configuration of the thread trimming device 13 relating to the movable knife 14 will be described with reference to FIG. 2. An L-shaped support is provided on a knife device mounting plate 18 fixed to the upper surface of the tip of the sewing machine bed 8 with screws 17. 19 is attached through an elongated hole 20a and a fixing screw 20b so that the initial position can be adjusted. A movable knife base mounting plate 22 is attached to the rising plate portion of the support 19 via a vertically long hole 21a and a fixing screw 21b so that the vertical position can be adjusted. The needle plate 15 is located below the movable knife base mounting plate 22. On the horizontal plate portion located on the side of the needle plate 15, the movable knife base 25 is positioned around the axis (support shaft) of the step screw 23 and the needle through the step screw 23 and the disc spring 24. A reciprocating swing is attached along the horizontal plane between the side portions of the plate 15.

  A position of the movable knife 14 formed in a substantially U shape in a plan view is adjusted in a direction in which a rocking radius thereof is adjusted via a long hole 26a and a set screw 26b at one end portion of the movable knife base 25. One end of a movable knife lever 29 that is fixed in a movable manner and has a long hole 28 that fits into a pin screw 27 that is screwed to the other end of the tip of the movable knife base 25 is bent in an L shape. The rod 8 is directly connected to the movable rod 31a of the air cylinder 31 so as to linearly extend and retract in the front-rear direction via the mounting plate 30 via the mounting plate 30 and via the rod end 32 and the connecting rod 33, and The movable knife lever 29 is supported by a movable knife lever guide 35 fixed to the knife device mounting plate 18 via a screw 34 so as to reciprocate linearly via a roller 36.

  With the above configuration, when the air cylinder 31 is expanded and contracted, the expansion / contraction driving force is transmitted to the movable female lever 29 via the movable rod 31a, the rod end 32 and the connecting rod 33, and the movable female lever 29 is transferred to the movable female lever guide 35. The guided reciprocating drive moves linearly, and the reciprocating driving force is transmitted to the movable knife base 25 through the long hole 28 and the pin screw 27, so that the movable knife base 25 and the movable knife 14 are axially centered on the step screw 23. It is configured to be reciprocally driven and oscillated along a horizontal plane between a lower position of the needle plate 15 and a side portion position of the needle plate 15 with the (support shaft) as a center, and the movable knife base is mounted. By adjusting the position of the plate 22 up and down via the vertically long hole 21a and the fixing screw 21b, the reciprocating rocking motion path of the movable knife 14 is configured to be vertically adjustable.

  Further, on one side of the U-shape of the movable knife 14 formed in a substantially U shape in plan view, the movable knife 14 moves from a lateral position of the needle plate 15 toward a position below the needle plate 15. When the forward drive swings, a needle thread guide member 14A having a sharp tip portion 14a is integrally extended downward and obliquely downward in the forward swing direction.

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

  In the buttoning step immediately after the operation of the root winding button sewing machine 1, as shown in FIGS. 3A and 3B, a seam is formed by the cooperative action of the vertical movement of the needle 3 and the rotational movement of the looper 9. Then, the button B is sewn on the folded fabric W. Then, the thread trimming device 13 starts operating when the buttoning 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. 4A, the needle thread portion 12a on the side connected to the end of the buttoning thread 10 is between the buttoning thread 10 and the looper 9. And the needle thread portion 12b inserted and held in the needle hole at the tip of the needle 3 are stretched and held in a substantially triangular loop shape gradually narrowing toward the upper part, and the movable knife 45 of the thread trimmer 13 is Under the needle plate 15, the two needle thread portions 12a and 12b in a substantially triangular loop shape are waiting at the side position.

  Next, the air cylinder 31 is driven to extend, and the driving force is transmitted to the movable knife base 25 via the movable rod 31a, the rod end 32, the connecting rod 33, the movable knife lever 29, the long hole 28, and the pin screw 27. The movable knife base 25 and the movable knife 14 are driven and swung in the forward direction from the lateral position toward the lower position of the needle plate 15 around the axis (support axis) of the step screw 23. As shown in FIG. 4B, the sharp tip 14a of the needle thread guide member 14A that is integrally extended from the movable knife 14 obliquely forward and downward in accordance with the forward drive swing of the movable knife 14 is shown. As described above, one needle thread portion on the side to be cut by entering the wide portion below the substantially triangular loop space S formed by the two needle thread portions 12a and 12b, that is, the button attaching thread 10 The needle thread portion 12a on the side continuous with the end portion is reliably captured.

  The needle thread portion 12a captured by the needle thread guide member 14A is relatively lifted and guided along the inclined side of the needle thread guide member 14A along with the forward drive swing of the movable knife 14 so as to form a substantially triangular loop space. After the narrow needle portion 12a at the upper part of S is guided to the movable knife 14 and hooked, the movable knife 14 is closest to the cloth W called the needle plate 15 as shown in FIG. The needle knife portion 12a is cut at a narrow portion of the substantially triangular loop space S due to a sliding contact with the fixed knife 16 formed at the portion.

  After that (after the yarn is cut), the air cylinder 31 is driven to contract, and the driving force causes the movable knife 14 to move backward in the direction of the arrow z along the horizontal plane as shown in FIG. On the other hand, the other needle thread portion 12b is held by a wiper (not shown) and is discharged to the rear side of the vertical movement path of the needle 3.

  When the buttoning process and the yarn cutting operation with the predetermined number of stitches are completed, the button holder 6 is turned 90 °, and the button B is switched to the vertical posture in the root winding process with respect to the fabric W. Transition to the winding process.

  In this root winding process, as shown in FIGS. 5A and 5B, the needles 3 are alternately dropped to the left and right positions of the outer peripheral portion of the buttoning thread 10 to cooperate with the rotational movement of the looper 9. Thus, the root thread 37 is sequentially wound around the buttoning thread 10 to reinforce the buttoning thread 10.

  When the root winding process with a predetermined number of stitches is completed, the thread trimming device 13 starts operating again, and a thread cutting operation is performed to cut the needle thread portion connected to the end of the root winding thread 37. However, since the yarn cutting operation after the end of the root winding step is performed in the same manner as the yarn cutting operation after the end of the buttoning step, detailed description and illustration thereof are omitted.

  As described above, according to the thread trimming device 13 of the present invention, the movable knife 14 is centered on the support shaft at the side portion of the needle plate 15 after the buttoning step and the root winding step are finished. The sharp tip portion 14a of the needle thread guide member 14A that is integrally extended obliquely forward and downward from the movable knife 14 in accordance with the forward drive swinging toward the lower position of the needle knife has two needle threads. One needle thread portion on the side to be cut by entering a wide portion below the substantially triangular loop space S formed by the portions 12a and 12b, that is, the end portions of the buttoning thread 10 and the root winding thread 37. The needle thread portion 12a on the side is reliably captured, and the captured needle thread portion 12a is guided to be relatively lifted along the inclined side of the needle thread guide member 14A as the movable knife 14 continues to swing forwardly. To the movable knife 14, and this movable 14 and the needle plate 15 is cut at the narrow portion of the substantially triangular loop space S by the sliding contact action of the fixed knife 16 formed at a location closest to the fabric W such as the needle plate 15. Become. Therefore, it is possible to reliably cut only the needle thread portion 12a on the side that requires cutting, without mistakes. For example, when viewed in the state after the root winding process, as shown in FIG. The needle thread portion 12a on the side connected to the end of the fabric can be cut with the length exposed on the surface of the fabric W being very short, so that the thread residue is hardly noticeable and the appearance after buttoning is improved. Can do.

In addition, the movable knife 14 is cut by the sliding contact with the fixed knife 16 formed at a fixed position of the needle plate 15 instead of being pushed only by the movable knife 14. Therefore, the movable knife 14 has a sharpness like a cutter blade. It is not necessary to use a sharp thin-walled material, and therefore, a predetermined yarn cutting performance can be ensured even when used continuously over a long period of time with very little blade breakage or breakage. Therefore, the replacement and maintenance cycle for keeping the sharpness of the movable knife 14 always good can be extended for a very long time, so that the number of operations for maintenance can be reduced, and the running cost can be reduced.
In a state where the fixed position of the needle thread T that has been cut from the cloth after buttoning is forcibly held and fixed between the thread gripping piece 17 and the thread hooking portion 8a at the tip of the wiper 8, the wiper 8 and the thread gripping piece 17 can be moved back and forth, so that the needle thread T can be surely prevented from coming off from the yarn hooking portion 8a, and even the slippery needle thread T can be prevented. Since the thread length that can be removed to the side can be stabilized without causing slippage in the longitudinal direction of the T, it is possible to reliably and stably form the seam of the first stitch at the start of the next sewing. Therefore, even when the next sewing is button-attached or root-wrapped sewing, it is possible to always ensure reliable and well-finished sewing without variations in the seam.

  In particular, as shown in the above embodiment, a movable knife in which the movable knife 14 is formed in a substantially U shape in plan view and the needle thread guide member 14A is integrally extended from one side of the U letter is used. As a result, the needle thread portion 12a that has been captured and guided by the needle thread guide member 14A can be reliably locked and held at a fixed position, and the thread can be cut with a short thread remaining length.

  Further, the position of the swinging movement path of the movable knife 14 can be adjusted up and down in accordance with the thickness of the button B to be sewn, so that the thread having any thickness can be threaded. Yarn cutting with a short remaining length can be reliably and satisfactorily performed.

  FIGS. 7 and 8 are an enlarged exploded perspective view and an enlarged partially cutaway side view of a mounting portion of a thread trimming device 13 which is a main part of a sewing machine with a root winding button according to a second embodiment of the present invention. A specific configuration for configuring the swing movement path of the movable knife 14 to be vertically adjustable in accordance with the thickness of the button B will be described below.

  In this second embodiment, the movable knife base mounting plate vertical position adjusting screw 38 is overlapped on the holding plate 39 and a holding plate 39 that holds the screw adjusting portion 38a such as a driver groove so as to be rotatable upward. The L-shaped support 19 is fixed and integrated with a set screw 40, and the fixed and integrated holding plate 39 and L-type support 19 are formed on the female device mounting plate 18 with a long hole 20a and a fixing screw 20b. The initial position is adjustable. A movable knife base mounting plate 22 is attached to the rising plate portion of the L-shaped support 19 via a vertically long hole 21a and a fixing screw 21b so that the vertical position can be adjusted. The movable knife base mounting plate vertical position adjusting screw 38 is screwed into a vertically penetrating state in a female screw hole 22a formed in the horizontal flat plate portion. Since other configurations are the same as those of the first embodiment, illustration and description thereof are omitted.

  In the thread trimming device 13 according to the second embodiment having the mounting portion configuration as described above, the fixing screw 21b is loosened and the vertical position adjusting screw 38 is moved to the right via a screwdriver or the like engaged with the screw adjusting portion 38a. By rotating counterclockwise or counterclockwise, the movable knife mounting plate 22 is moved up and down in the direction of arrow ud in FIG. When the movable knife mounting plate 22 is moved up and down to a predetermined height position, the rocking movement path of the movable knife 14 is changed according to the thickness of the button to be sewn and the like by tightening and fixing the fixing screw 21b. It is possible to adjust the position up and down.

  According to the thread trimming device 13 of the second embodiment that employs the mounting portion as described above, the position and posture of the L-shaped support 19 and the movable knife mounting plate 22 with respect to the knife device mounting plate 18 are fixed. Thus, the vertical position of the swing movement path of the movable knife 14 can be adjusted. As a result, the thread cutting action by the movable knife 14 and the needle thread catching / pull-up guide action by the needle thread guide member 14A are always reliably and stably performed. Can be done.

  Further, in the first and second embodiments described above, the thread cutting device 13 is operated to perform the thread cutting operation after the buttoning process and the root winding process are finished. For example, in a button sewing machine that does not have a root winding process, the yarn cutting operation is performed only after the buttoning process is completed, and the same effect is obtained as described above.

DESCRIPTION OF SYMBOLS 1 Neck 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 Needle thread guide member 14a Sharp tip 15 Needle plate 16 Fixed knife 37 Root wound thread B Button W Fabric S A substantially triangular loop space

Claims (3)

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 movable knife 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 movable knife has a needle drop part, and a position between a lower position of the needle plate and a side part position of the needle plate around a support shaft provided on a side part of a needle plate for setting a cloth in the needle drop part. The movable knife is configured to be swingable in a reciprocating manner along a horizontal plane. The movable knife of the movable knife swings in the forward direction from the side position of the needle plate toward the lower position of the needle plate. When entering the wide portion below the substantially triangular loop space formed by the two needle thread portions, and with the forward drive swing along the horizontal plane of the movable knife after the entry, // A needle-thread guide member with a sharp tip that guides the needle thread portion that is connected to the end of the root winding thread relatively upwardly extends integrally from the movable knife toward the diagonally forward and downward direction in the forward swing direction. And the needle plate is lifted and guided on the needle plate. Thread cutting device of button sewing machine, wherein a fixed knife for cutting the portion by sliding action of the movable knife is formed. The said movable knife is formed in the substantially U shape in planar view, The said needle thread guide member is integrally extended toward the said diagonally forward downward from the one side part side of the U shape. Thread trimmer for sewing machine with buttons. The thread trimming device for a button-equipped sewing machine according to claim 1 or 2, wherein the movable knife is configured such that a reciprocal swing movement path thereof can be adjusted in a vertical direction.

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