JP2009066191A - Seam ravel preventing method and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seam ravel preventing method capable of preventing seam ravel from the end side of sewing end of seam while gathering and disposing components inside a sewing machine bed, and an apparatus therefor. <P>SOLUTION: In a sewing machine provided with a vertically moving needle and a looper swinging forward and backward while clamping the needle, the apparatus is provided with a receiving knife disposed on the retreat position side of the looper, a hook moving back and forth from the receiving knife and a route change means for changing the back and forth movement route of the hook. At the end of sewing, in the state that the looper is moved forward, the hook is moved forth and engaged with a looper thread from a loop-like needle thread to the looper, the engaging part of the looper thread is cut with the receiving knife by the back movement following it, the back and forth movement route of the hook is changed after the back and forth movement of the hook, the sewing machine is driven for one stitch, and the looper is moved forward again. The hook is moved forth to be advanced to and engaged with the loop-like needle thread captured by the looper and is engaged with the looper thread from the loop-like needle thread to the looper, and the engaging part of each thread is cut with the receiving knife by the back movement following it. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for preventing fraying of a seam from the end of a seam when a double ring seam or a flat seam is formed on a fabric by a sewing machine.

  As a conventional stitch fray prevention device, the sewing machine is driven by one stitch after engaging the looper thread hook with the looper thread from the loop needle thread to the looper with the looper swinging to the forward position at the end of sewing. After that, the looper thread engaging part of the looper thread, the looped needle thread captured by the looper and the looper thread from the looped needle thread to the looper are captured by the thread trimming hook, and each thread is arranged on the retracted position side of the looper. What is cut with a thread trimming knife (receiving knife) is known (see, for example, Patent Document 1). The looper thread hook and the thread trimming hook are disposed in the sewing machine bed.

JP 2006-314762 A (Pages 6-11, FIGS. 8-12)

However, in the conventional stitch fray prevention device, the looper thread from the loop-shaped needle thread to the looper is engaged by a plurality of hooks, that is, a looper thread hook and a thread trimming hook. Parts were scattered in the machine bed.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a stitch fraying prevention method and apparatus capable of preventing fraying of a stitch from the stitch end end side while arranging components in a sewing machine bed. It is an object.

  In order to achieve the above object, the present invention achieves at least one needle inserted and moved up and down and swings forward and backward between a forward position and a backward position with the needle interposed therebetween. In a sewing machine equipped with a looper for inserting a looper thread that forms a double loop seam, a receiving knife arranged at the retracted position side of the looper and a hook for catching the thread at the tip, and reciprocating from the receiving knife. And a path changing means for changing the reciprocating path of the hook to the first path or the second path, with the looper swinging to the forward position at the end of sewing, The hook moves forward along the first path and engages with the looper thread extending from the loop needle thread to the looper, and the subsequent movement of the hook receives the looper thread engaging portion and cuts it with the knife. The looper thread remaining on the fabric side by the loop of the final loop needle thread The reciprocating path of the hook is changed from the first path to the second path after the hook is reciprocated and the sewing machine is driven by one stitch to swing the looper to the forward position again. Engage with the loop needle thread that moves forward along the path and is captured by the looper, and engages with the looper thread from the loop needle thread to the looper, and the subsequent return movement engages each thread. It is characterized by being cut with a scalpel.

  The thread cutter is fixed to the hook and has a first elongated hole and a second elongated hole along the longitudinal direction, and is inserted into the first elongated hole and the second elongated hole separately to support the slidable operating piece. And a first drive member that drives the operating piece, and the path changing means is formed in one of the first long hole or the second long hole and is opposed to the first path along the longitudinal direction. The first guide surface and the second guide surface for the second path, and the second guide member connected to the operating piece and engaging the first guide surface or the second guide surface with the support member are desirable.

  According to the present invention, when the looper is swung to the forward position at the end of sewing, the hook is reciprocated along the first path from the receiving knife so that the looper thread engaging portion is received and cut by the knife. As a result, the looper yarn remaining on the fabric side is held in the loop of the final loop-shaped needle thread, so that even if the looper yarn is pulled, the stitches are not frayed. In addition, after the hook is reciprocated along the first path, the sewing machine is driven for one stitch, and after the hook is reciprocated, the reciprocating path of the hook is changed from the first path to the second path. The loop needle thread captured by the looper and the looper thread from the loop needle thread to the looper are received and cut by the knife, so that the looper can be connected to the looper without interspersing the hooks. The looped needle thread and the looper thread extending from the looped needle thread to the looper can be cut.

  If the first guide surface and the second guide surface formed opposite to the elongated hole of the hook fixing bracket are included as a route changing means for changing the hook reciprocating route to the first route or the second route, a new configuration is provided. Can be kept to a minimum.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The sewing machine applied to the present invention includes an arm portion 1A and a bed portion 1B, and the bed portion 1B includes a cylinder bed 1b on the distal end side. The cylinder bed 1b includes a feed dog 2 that moves four times up and down and forwards the cloth in the direction of arrow F, a looper 3 that moves elliptically in the left and right directions, and a needle plate 4 that is fixed to the screw hole 4a (see FIG. 2). ) Is provided. A needle bar 7 is provided above the cylinder bed 1b. The needle bar 7 is connected to a needle bar vertical drive mechanism (not shown) in the arm 1 </ b> A, and the left needle 5 and the right needle 6 are attached to the lower end of the needle bar 7. The tip portions of the left and right needles 5 and 6 penetrate the needle plate intermittently by the vertical movement of the needle bar 7. The looper 3 is fixed to the looper base 3b at the tip of the looper shaft 3a with screws 3c, and the looper shaft 3a swings in a direction orthogonal to the cloth feeding direction F in conjunction with the vertical movement of the needle bar 7. That is, the looper 3 swings forward and backward between the forward position and the backward position with the tip portions of the needles 5 and 6 sandwiched below the needle plate 4. When the left and right needles 5 and 6 and the looper 3 cooperate, the needle threads 8 and 9 inserted into the left and right needles 5 and 6 and the looper thread inserted into the looper 3 as shown in FIGS. 10, a double ring stitch S is formed on the fabric W. The needle yarns 8 and 9 and the looper yarn 10 are connected to a yarn supply source via a tension tensioning device TT. Further, as shown in FIG. 14, the thread tensioner TT has a known thread loosening tool TL, and the tension applied to the respective threads 8, 9, and 10 is released simultaneously by the operation of the thread loosening tool TL.

  A thread cutter 11 having the following configuration is provided on the base side (right side) of the cylinder bed 1b. The receiving knife 12 of the thread cutter 11 is disposed on the retracted position side of the looper 3 and is fixed to the tip of the bracket 16 with a screw 15 together with a hook guide 13 and a leaf spring 14. A screw 19 fixed to the bed inner lid 17 via a washer 18 is disposed in a long hole 16a formed in a base end portion of the bracket 16, and the bracket 16 is supported by the washer 18 so as to be rotatable and slidable. The screws 20 inserted through the tip of the bracket 16 pass through the long hole 21 a of the thread holding spring 21 and are screwed into the screw hole 22 a of the fixing piece 22. A recess 16 b is formed at the base end of the bracket 16. One end of the wire spring 23 is in contact with the recess 16 b, and the other end of the wire spring 23 is fixed to the bed inner lid 17 with a screw 24. As a result, the bracket 16 is constantly urged toward the locking piece 25 fixed to the bed inner lid 17.

  A hook 26 is slidably disposed between the receiving knife 12 and the hook guide 13. The hook 26 has a looper thread heel part 26a and a needle thread heel part 26b at the front end of the abdomen, and the back side of the hook 26 is substantially linear. The base end portion of the hook 26 is fixed to the operating piece 27 by a screw 28. The operating piece 27 is horizontally long and has a first long hole 29 and a second long hole 30 along the longitudinal direction, and screws 31 and 33 are attached to the bed inner lid 17. A circular collar 32 inserted through the screw 31 is disposed in the first long hole 29, and a circular collar 34 inserted through the screw 33 is disposed in the second long hole 30. That is, the operating piece 27 is supported by the collars 32 and 34 so as to be slidable. The operating piece 27 is connected to a link member 36 rotatably supported by a screw 35 on the bed inner lid 17, and the link member 36 is connected to a piston rod 37 a of the first air cylinder 37. When the piston rod 37a of the first air cylinder 37 advances and retreats, the operating piece 27 is driven. The operating piece 27 is formed with a protruding piece 27a, and the bracket 16 is formed with an engaging portion 16c for engaging the protruding piece 27a. It is desirable that a part of the bracket 16 is slidably engaged on both sides of the operating piece 27 so that the protruding piece 27a and the engaging portion 16c are properly engaged.

  The second elongated hole 30 of the operating piece 27 is provided with a first guide surface 30a and a second guide surface 30b that are opposed in the longitudinal direction. The first guide surface 30a is composed of a cam surface extending continuously in three directions, and the second guide surface 30b is composed of a cam surface extending continuously in two directions, whereby the distance between both guide surfaces 30a, 30b is It is wide on the way. One end of a wire work spring 38 is fixed to the base end portion of the operating piece 27 with a screw 39. The other end of the wire work spring 38 is fixed to a long-angle member 41 fixed to the piston rod 40a of the second air cylinder 40. When the piston rod 40 a of the second air cylinder 40 advances and retreats, the first guide surface 30 a or the second guide surface 30 b of the second long hole 30 is engaged with the washer 34 supported by the screw 33.

  A thread guide 42 is fixed to the operating piece 27 with a screw 43, and a U-shaped thread guide 44 is fixed to the end of the bed inner lid 17. A known yarn reel 45 is fixedly disposed between the yarn path guide 42 and the looper 3, and a small tensioner 46 is disposed between the U-shaped yarn guide 44 and the thread tensioner TT. The yarn reel 45 has a pair of L-shaped yarn guides 45a and 45a, and a hook-like cam (not shown) protruding and retracting from the yarn reel 45 is engaged with the looper yarn 10 between the L-shaped yarn guides 45a and 45a. . The subtensioner 46 includes two thread tension plates 48 and 48 that are pressed against each other by a spring 47, and a release member 49 that interposes a claw 49a between the two thread tension plates 48 and 48 when operating. The pressure contact force of the thread tension plates 48, 48 by the spring 47 is stronger than the pressure contact force of the thread tensioner TT arranged on the yarn supply source side. When this pressure contact force acts on the looper thread 10, the looper thread 10 is moved from the thread tensioner TT. It is not pulled out to the looper 3 side. Normally, a claw 49a is interposed between the thread tension plates 48, 48 of the sub-tension device so that no tension is applied to the looper thread 10 between the thread tension plates 48, 48.

The operation of the fraying prevention device according to the present invention will be described with reference to FIGS.
When the sewing end of the fabric W is approached and the needles 5 and 6 are at the top dead center and the looper 3 is in the forward position as shown in FIG. 5, the first air cylinder 37 is operated to move the piston rod 37a to the arrow. Retreat in the X direction. As the piston rod 37a moves backward, the link member 36 rotates around the screw 35, and the operating piece 27 advances toward the needle plate 4. At this time, the piston rod 40 a of the second air cylinder 40 has advanced, and the operating piece 27 moves with the first guide surface 30 a of the second long hole 30 engaged with the collar 34 supported by the screw 33. As the operating piece 27 advances, the bracket 16 advances together until the bracket 16 comes into contact with the locking piece 25. Subsequently, when the operating piece 27 is advanced, the projecting piece 27a of the operating piece 27 is separated from the engaging portion 16c of the bracket 16, and the hook is interposed between the receiving knife 12 and the thread holding spring 21 as shown in FIG. 26 will advance. By a series of advancing operations of the operating piece 27, the hook 26 is connected to the first path (a → b1 → c → d) indicated by the one-dot chain line in FIG. 12, that is, the loop needle threads 8L and 9L captured by the looper 3. While passing through the outside of the ring, it moves forward along a path engaging with the looper thread 10a from the loop-shaped needle thread 8L to the looper 3. At the end of the forward movement of the hook 26 along the first path, the back side of the hook 26 comes into contact with the loop needle threads 8L and 9L, and the hook portion 26a of the hook 26 passes over the side of the looper thread 10a. Yes.

  Thereafter, the first air cylinder 37 is operated to advance the piston rod 37a in the arrow Y direction. As the piston rod 37a advances, the link member 36 rotates around the screw 35, and the operating piece 27 moves backward. At this time, the advancement of the piston rod 40a is maintained, and the hook 26 moves backward along the first path. By this backward movement, the looper thread collar 26a of the hook 26 pulls the looper thread 10a extending from the loop needle thread 8L to the looper 3 to the knife 12, and the engaging portion of the looper thread 10a is engaged with the collar 26a and the receiving knife. 12 is cut in cooperation with 12. The looper thread 10x remaining on the sewing machine side by this cutting is sandwiched between the receiving knife 12 and the thread holding spring 21, and the end of the looper thread 10y remaining on the fabric W side is attached to the right needle 6 as shown in FIG. In addition to staying in the loop of the last loop needle thread 9L that is continuous, it remains in the ring of the final loop needle thread 8L that is continuous to the left needle 5. When the hook 26 is further retracted, the projecting piece 27a of the operating piece 27 is engaged with the engaging portion 16c of the bracket 16, and then the operating piece 27 and the bracket 16 are retracted together.

  After the operating piece 27 and the bracket 16 are retracted together, and the reciprocating motion of the hook 26 and the receiving knife 12 is completed, the second air cylinder 40 is operated to retract the piston rod 40a, and the second elongated hole 30 is The guide surface 30 b is kept engaged with the collar 34 supported by the screw 33. As a result, the reciprocating path of the hook 26 is changed from the first path to the second path. After the second air cylinder 40 is actuated, the sewing machine is driven to lower the needles 5 and 6 and retract the looper 3 to the retracted position (see FIG. 8). When the looper 3 is retracted, the loop-shaped needle threads 8L and 9L that are detached from the looper 3 gradually converge on the fabric W. When the sewing machine is continuously driven, the needles 5 and 6 rise through the bottom dead center and the looper 3 moves forward from the retracted position. At this time, the looper 3 captures new loop-shaped needle threads 8LL and 9LL formed at the rear portions of the needles 5 and 6, and a part of the looper thread 10x remaining on the sewing machine side is in the loop of the loop-shaped needle threads 8LL and 9LL. Will pass.

  When the needles 5 and 6 again reach the top dead center and the looper 3 reaches the forward position, the claw 49a of the release member 49 is retracted, and the pressure contact force of the thread tension plates 48 and 48 by the spring 47 is applied to the looper thread 10. To be granted. Thereafter, the first air cylinder 37 is operated to retract the piston rod 37a in the arrow X direction. As the piston rod 37a moves backward, the link member 36 rotates around the screw 35, and the operating piece 27 advances toward the needle plate 4. At this time, the piston rod 40 a of the second air cylinder 40 is retracted, and the operating piece 27 moves with the second guide surface 30 b of the second long hole 30 engaged with the collar 34 supported by the screw 33. As the operating piece 27 advances, the bracket 16 advances together until the bracket 16 comes into contact with the locking piece 25. As a result, as shown in FIG. 9, the hook 26 and the receiving knife 12 move from the standby position to the operating position.

  When the operating piece 27 is subsequently advanced, the projecting piece 27a of the operating piece 27 is separated from the engaging portion 16c of the bracket 16, and the hook 26 is advanced from between the receiving knife 12 and the thread holding spring 21, as shown in FIG. As shown, the end of the looper thread 10x remaining on the sewing machine side is released and hangs down from the final end of the seam S. The hook 26 is moved to the second path (a → b2 → c → d) indicated by the one-dot chain line in FIG. 12, that is, the loop needle threads 8LL and 9LL captured by the looper 3 by a series of advance operations of the operating piece 27. At the same time as entering and engaging, it moves forward along a path engaging with the looper thread 10aa from the loop needle thread 8LL to the looper 3. At the end of the forward movement of the hook 26 along the second path, the collar portions 26a and 26b are in a state of passing through the loop needle threads 8LL and 9LL. At this time, the yarn path guide 42 advances to the looper 3 side together with the operating piece 27, and the looper thread 10 between the U-shaped thread guide 44 and the L-shaped thread guide 45 is wound by the thread path guide 42. As a result, the looper thread 10x remaining on the sewing machine side is slightly pulled back from the stitches S to the looper 3 side, and the amount of drooping from the stitches S is shortened.

  Thereafter, the first air cylinder 37 is operated to advance the piston rod 37a in the arrow Y direction. As the piston rod 37 advances, the link member 36 rotates around the screw 35 and the operating piece 27 moves backward. At this time, the backward movement of the piston rod 40a is maintained, and the hook 26 moves backward along the second path. By this backward movement, the looper thread collar 26a of the hook 26 pulls the looper thread 10aa extending from the loop needle thread 8LL to the looper 3, and the needle thread collar 26b is captured by the looper 3. The loop needle thread 8LL, Tow 9LL. When the loop-shaped needle threads 8LL and 9LL are captured by the hook portion 26b, the loop-shaped needle threads 8LL and 9LL are smoothly pulled when the thread loosening device TL is operated. When the collar portions 26a and 26b reach the receiving knife 12, the engaging portions of the yarns 8LL, 9LL, and 10aa are cut in cooperation with each other. The looper thread 10z finally remaining on the sewing machine side by this cutting is sandwiched between the receiving knife 12 and the thread holding spring 21, and the thread waste 10xx of the looper thread is formed at the final end of the seam S as shown in FIG. stay.

  When the hook 26 is further retracted, the projecting piece 27a of the operating piece 27 is engaged with the engaging portion 16c of the bracket 16, and then the operating piece 27 and the bracket 16 are retracted together to complete the operation of the apparatus. As long as the looper yarn 10y remaining on the fabric W side by the first reciprocating movement of the hook 26 is not pulled out from the final left loop needle yarn 8L, no fraying occurs at the sewing end of the fabric. It should be noted that the yarn waste 10xx of the looper yarn remaining at the end of the seam S is not particularly problematic as it is, but if it becomes an obstacle, the end portion of the yarn waste may be removed by pulling.

  The yarn loosening device TL arranged on the yarn supply source side may be operated at the time of the first reciprocating motion of the operating piece 27 and the operation may be continued even after the first reciprocating motion of the operating piece 27. In this case, the sewing machine is driven for one stitch while the needle thread is loosened. As a result, an appropriate tension is not generated on the loop needle thread captured by the looper 3. In order to solve this problem, it is preferable to attach a yarn handing device so as to remove the looseness of the needle thread when the sewing machine is driven after the first reciprocating movement of the operating piece 27. Although not described in detail in the present embodiment, as shown in FIG. 6, the hook 26 comes into contact with the loop needle threads 8L, 9L from the outside during the first reciprocating motion. Therefore, if the front and rear width of the hook 26 is shortened as much as possible to reduce interference with the loop needle thread, the possibility of cutting the loop needle thread is reduced.

  Further, in the present embodiment, the elongated hole of the operating piece is deformed in order to change the reciprocating path of the hook 26, but the present invention is not limited to this. For example, as shown in FIG. 13, the first and second long holes 50a and 50b of the operating piece 50 may be formed linearly. At that time, it is sufficient that the circular support members inserted into the first and second elongated holes 50a and 50b can be moved in a direction intersecting the longitudinal direction of the elongated holes with a pen-type cylinder. The support member may be made into an eccentric so that the support member can be rotated by a rotary solenoid. Also, the reciprocating path of the hook 26 can be changed by fixing the thread cutter 51 itself to the moving piece of the rodless cylinder. Although not described in detail in the present embodiment, the locking piece 25 is fixed to the bed inner lid 17 with a screw so that the locking position of the locking piece 25 can be adjusted when the screw is loosened. The operating position of the receiving knife 12 can be changed.

It is the outline perspective view showing the peripheral composition of the stitch fray prevention device concerning the present invention. It is the whole top view explaining the stitch fraying prevention device concerning the present invention. It is the components expanded view which showed the principal part of the apparatus. It is a schematic threading diagram of a looper thread used for a sewing machine. It is the schematic perspective view which showed the operation | movement process of the stitch fraying prevention apparatus which concerns on this invention. It is the schematic perspective view which showed the operation | movement process of the apparatus. It is the schematic perspective view which showed the operation | movement process of the apparatus. It is the schematic perspective view which showed the operation | movement process of the apparatus. It is the schematic perspective view which showed the operation | movement process of the apparatus. It is the schematic perspective view which showed the operation | movement process of the apparatus. It is the schematic perspective view which showed the operation | movement process of the apparatus. FIG. 6 is a schematic explanatory diagram showing an operation locus of a hook 26. It is the schematic explanatory drawing which showed the modification of the stitch fraying prevention apparatus which concerns on this invention. It is the external appearance perspective view which showed the sewing machine carrying the same apparatus.

Explanation of symbols

3 Looper 5, 6 Needle 8, 9 Needle thread 8L, 9L Loop needle thread 8LL, 9LL New loop needle thread 10 Looper thread 11 Thread cutter 12 Receiving knife 26 Hook 27 Actuating piece 26a, 26b Hook 29 First Long hole 30 Second long hole 30a First guide surface 30b Second guide surface 33 Screw 34 Collar 40 Second air cylinder

Claims (3)

Insert at least one needle that passes through the needle thread and moves up and down, and a looper thread that moves forward and backward between the forward position and the backward position across the needle to form the needle thread and the double ring stitch. In sewing fabric with a sewing machine equipped with a looper,
When the looper swings to the forward position at the end of sewing, the hook moves forward along the first path that engages the looper thread from the loop needle thread to the looper from the receiving knife arranged on the retracted position side of the looper. A first step of receiving the looper thread engaging portion of the looper thread by a backward movement and cutting with a knife and retaining the looper thread remaining on the cloth side in the loop of the final loop-shaped needle thread;
A second step of changing the reciprocating path of the hook from the first path to the second path after the reciprocating movement of the hook;
A third step of driving the sewing machine for one stitch and swinging the looper to the advanced position again with the looper yarn remaining on the fabric side held in the loop of the final loop-shaped needle yarn;
After the second step and the third step, along the second path that engages the loop needle thread that is hooked by the looper from the receiving knife into the loop needle thread and engages the looper thread from the loop needle thread to the looper. A stitch fraying prevention method comprising: a fourth step of moving forward and then receiving the engaging portion of each thread by a backward movement and cutting with a knife. Insert at least one needle that passes through the needle thread and moves up and down, and a looper thread that moves forward and backward between the forward position and the backward position across the needle to form the needle thread and the double ring stitch. In a sewing machine equipped with a looper,
A thread scissor including a receiving knife arranged on the retreat position side of the looper, and a hook having a hook part for catching a thread at the tip part and reciprocating from the receiving knife;
Path changing means for changing the reciprocating path of the hook to the first path or the second path,
At the end of sewing, with the looper swinging to the forward position, the hook moves forward along the first path from the receiving knife and engages with the looper thread from the loop needle thread to the looper. The looper thread engaging portion is cut with a knife and the looper thread remaining on the fabric side by the cutting is held in the loop of the final loop-shaped needle thread. The loop is changed from the first path to the second path, and the sewing machine is driven by one stitch to swing the looper to the forward position again, and the hook moves forward along the second path from the receiving knife and is captured by the looper. The needle thread is engaged and engaged with a looper thread extending from the loop needle thread to the looper, and the subsequent return movement receives each thread's engaging portion and cuts with a knife. Stitch fray prevention device. Thread cutter
An operating piece fixed to the hook and having a first slot and a second slot along the longitudinal direction;
A circular support member that is inserted into the first long hole and the second long hole and supports the operation piece in a slidable manner;
A first drive member for driving the operating piece;
The route change means
A first guide surface for the first path and a second guide surface for the second path which are formed in one of the first long hole or the second long hole and are opposed in the longitudinal direction;
The stitch fray prevention device according to claim 2, further comprising a second drive member connected to the operating piece and engaging the first guide surface or the second guide surface with the support member.

Images