JP2010194066A - Thread cutter of sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thread cutter of a sewing machine capable of canceling clamping condition of a needle thread and a looper thread in an optimal timing during a movable knife goes forward. <P>SOLUTION: A thread tension adjusting means 33 for shifting to either one of a clamping condition providing tension by clamping the needle thread A and the looper thread C and a clamping canceling condition is arranged in the upper part of the sewing machine body 32. The movable knife 35 goes forward and rearward and cuts the needle thread A and the looper thread C in the lower part of a needle plate 34. One end part of an swinging arm 38 is connected to the sewing machine body 32 so as to be freely angularly displaceable and a follower 37 is arranged in a middle part between the other end part and the one end part. A long hole 39 is formed in a cam member 40 to keep the swinging arm 38 angularly displaced in the one direction or the other direction by the displacement of the cam member 40. The first link means 42 transmits the displacement of the other end part of the swinging arm 38 to the thread tension adjusting means 33 and the second link means 43 transmits the drive force of a driving means 41 to the movable knife 35 and moves the movable knife 35 forward and rearward. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thread trimming device for a sewing machine.

  FIG. 6 is a perspective view showing a configuration of a conventional thread cutting device 1 for a sewing machine. This prior art is described in Patent Document 1, for example. In a conventional thread trimming device 1 for a sewing machine, one end of an interlocking shaft 5 is connected to a piston rod 3 of a pneumatic cylinder 2 by a connecting block 4, and a needle is fixed by a cam member 6 fixed to the other end of the interlocking shaft 5. Needle thread and looper thread are clamped to a thread tension adjusting device (not shown), also called a thread retainer, to apply the desired tension, and the clamped state is released to release the tension of the needle thread and looper thread. In synchronism with the displacement of the interlock shaft 5, the substantially C-shaped movable knife 12 provided on the lower surface of the needle plate (not shown) is angularly displaced in the directions of arrows B1 and B2. The needle thread and the looper thread are configured to be cut.

  The axis of the interlocking shaft 5 and the axis of the piston rod 3 of the pneumatic cylinder 2 are parallel. The pneumatic cylinder 2 is realized by a single acting pneumatic cylinder, and the piston rod 3 is retracted in the direction of the arrow A1 by the air pressure, and is expanded in the direction of the arrow A2 by the spring force of the return spring 2a.

  One end of a push rod 7 is connected to the connection block 4, and one end of a first swing arm 9 is connected to the other end of the push rod 7 by a first pin 8. One end of a knife drive rod 11 is connected to the other end of the first swing arm 9 by a second pin 10, and the movable knife 12 is connected to the other end of the knife drive rod 11 by a third pin. 13 are connected so as to be angularly displaceable.

  An intermediate portion of the first swing arm 9 is pivotally supported on the machine body of the sewing machine by a fourth pin 14. When the piston rod 3 is retracted in the direction of the arrow A 1, the first swing arm 9 is moved to the fourth pin 14. And move the movable knife 12 through the knife drive rod 11 to advance it in the direction of the arrow B1. When the piston rod 3 extends in the direction of the arrow A2, the first swing arm 9 is angularly displaced in the opposite direction around the axis of the fourth pin 14, and the movable knife 12 is pulled via the knife drive rod 11. And move backward in the direction of arrow B2. The movable knife 12 is pivotally supported by the fifth pin 15 on the lower surface of the needle plate.

  The cam member 6 is formed of a long plate-like member that extends substantially parallel to the interlocking shaft 5, and first and second cam surfaces 6a and 6b are formed on the upper portion. The first cam surface 6a is formed to be inclined upward in the direction of the arrow A2. The second cam surface 6b is formed to extend horizontally from the upper end of the first cam surface 6a.

  The pneumatic cylinder 2 is provided substantially horizontally on a bracket 16 fixed to the back surface of the sewing machine body, and a lower end portion of a support frame 17 is fixed to the bracket 16. The center portion of the second swing arm 19 is connected to the upper end portion of the support frame 17 by a sixth pin 18 so as to be swingable around a horizontal axis of the sixth pin 18. A follower 20 guided by the first and second cam surfaces 6a and 6b is provided at one end of the second swing arm 19. The other end of the second swing arm 19 is connected to one end disposed below a connecting rod 23 that extends vertically by a seventh pin 21. The sixth and seventh pins 18 and 21 are realized by pin bolts.

  The other end portion disposed above the connecting rod 23 is connected to the yarn tension adjusting device, and the yarn tension adjusting device is moved upward and downward in the direction of the arrow C1 by the connecting rod 23. It is possible to switch between the pinched state of the needle thread and looper thread and the released state in which the pinched state is released.

  In such a thread trimming device 1, the needle thread and looper thread are elastically clamped during sewing to give an appropriate tension, and when the sewing operation is stopped, the needle thread and looper thread are stopped. Release the pinched state of the thread, release the tension during the sewing of the needle thread and the looper thread, and relax the needle thread and the looper thread when the movable knife 12 moves forward and backward in the direction of the arrow D2, The needle thread and the looper thread are prevented from being cut at an inappropriate timing.

Utility Model Registration No. 3136842

  The above-described prior art sewing thread trimming device 1 receives a follower 20 provided at one end of a second swing arm 19 by first and second cam surfaces 6a and 6b formed on an upper portion of a cam member 6, Since the connecting rod 23 is vertically displaced in the directions of the arrows C1 and C2 by moving the member 6 in the directions of the arrows A1 and A2, the movable knife 12 is moved forward in the direction of the arrow B2. Even if the first and second cam surfaces 6a and 6b are formed on the cam member 6 at a desired inclination angle so as to release the clamped state of the needle thread and looper thread by the thread tension adjusting device, the follower 20 smoothly follows. There is a problem that the clamped state of the needle thread and looper thread of the thread tension adjusting device cannot be released at an optimal timing while the movable knife 12 is moving forward in the direction of the arrow B1.

  An object of the present invention is to provide a thread trimming device for a sewing machine that can release a clamped state of a needle thread and a looper thread at an optimal timing while the movable knife is moving forward.

The present invention is provided in the upper part of the sewing machine main body, and includes either a clamped state in which the needle thread and the looper thread are clamped to apply tension to the needle thread and the looper thread, and a clamped release state in which the clamped state is released. Thread tension adjusting means switchable to either one of
A movable knife that cuts the needle thread and the looper thread by moving forward in the direction close to the needle drop position below the needle plate and moving backward in the direction away from the needle drop position;
One swinging end is connected to the sewing machine body so as to be angularly displaceable, and a swing arm provided with a follower at an intermediate portion between the other end and the one end,
A long hole into which the follower is movably fitted is formed, and the swing arm is angularly displaced in one direction by displacement in one direction, and the swing arm is angularly displaced in another direction by displacement in the other direction. Members,
Drive means for displacing the cam member in the one direction and the other direction;
The displacement of the other end of the swing arm is transmitted to the thread tension adjusting means, and the thread tension adjusting means is operated from the clamped state to the clamp release state or from the clamp release state to the clamp. First link means for operating to a wearing state;
A sewing machine thread trimming apparatus comprising: second link means for transmitting a driving force of the driving means to the movable knife and moving the movable knife forward and backward.

Further, the present invention is provided in an upper portion of the sewing machine main body, in a sandwiched state in which the needle thread and the looper thread are sandwiched to apply tension to the needle thread and the looper thread, and in a sandwiched unreleased state in which the sandwiched state is released. Thread tension adjusting means switchable to either one of
A movable knife that cuts the needle thread and the looper thread by moving forward in the direction close to the needle drop position below the needle plate and moving backward in the direction away from the needle drop position;
A displacement of the follower in a direction crossing the first and second directions, which is fixed to the sewing machine body and allows the displacement of the follower in a second direction opposite to the first direction and the first direction. A follower guide member provided with a follower guide part for preventing
A long hole is formed into which the follower is movably fitted, and the follower is displaced in the first direction by displacement in one direction along the intersecting direction, and by displacement in the other direction along the intersecting direction. A cam member for displacing the follower in the second direction;
Drive means for displacing the cam member in the one direction and the other direction;
The displacement of the other end of the swing arm is transmitted to the yarn tension adjusting means, and the yarn tension adjusting means is operated from the clamped state to the clamp release state or from the clamp release state to the clamp First link means for operating to a state;
A sewing machine thread trimming apparatus comprising: second link means for transmitting a driving force of the driving means to the movable knife and moving the movable knife forward and backward.

  Further, according to the present invention, a first cam surface that guides the follower when the cam member moves in the one direction and an inner periphery of the cam member facing the elongated hole, A second cam surface that guides when moving in the other direction is formed.

  According to the present invention, a hollow is provided in an intermediate portion between one end and the other end of the swing arm, and the cam member is movably fitted in the long hole of the cam member. The oscillating arm can be angularly displaced in one direction by the displacement in the direction, and the oscillating arm can be angularly displaced in the other direction by the displacement in the other direction of the cam member. According to the displacement, the follower can follow the elongated hole, and the thread tension adjusting means is operated at the timing corresponding to the optimum position immediately before the outer periphery of the needle thread hook that the movable knife is moving forward pushes the needle thread. The pinched state of the needle thread and the looper thread can be released.

  According to the present invention, the follower guide member allows the follower to be displaced in the first direction and the second direction, and prevents the displacement in the direction intersecting the first and second directions. The hole is movably fitted in the hole, the follower is displaced in the first direction by displacement of the cam member in one direction, and the follower is displaced in the second direction by displacement of the cam member in the other direction. Therefore, the follower can follow the elongated hole according to the displacement of the cam member in one direction and the other direction, and the outer peripheral portion of the needle thread hook that the moving knife is moving forward spreads the needle thread. The pinched state of the needle thread and looper thread by the thread tension adjusting means can be released at a timing corresponding to the immediately preceding optimum position.

  Further, according to the present invention, since the first cam surface and the second cam surface are formed in the elongated hole, the follower can be surely followed and displaced by the first and second cam surfaces and is movable. The needle thread and looper thread pinned state by the thread tension adjusting means can be released with higher accuracy at the timing corresponding to the optimum position immediately before the outer periphery of the needle thread hook while the knife is moving forward. Can do.

1 is a system diagram showing a configuration of a thread cutting device 30 for a sewing machine according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of a thread cutting device 30 for a sewing machine. It is a perspective view of a sewing machine 31 provided with a thread trimming device 30. FIGS. 4A and 4B are views for explaining the operation of the thread trimming device 30 of the sewing machine. FIG. 4A shows a state immediately before the movable knife 35 enters the right needle thread A1 loop, and FIG. Fig. 4 (3) shows the state in which the thread A1 is pushed and spread by the outer periphery of the needle thread hook 35a. 4 (4) shows the right needle thread A1, the center needle thread A2 and the left needle thread A3 being cut without resisting the spreading force by the needle thread hook 35a, and the looper thread C being the needle thread. FIG. 4 (5) shows a state in which the movable knife 35 has normally entered between the loops of the needle threads A1 to A3 and the looper thread C. FIG. . It is a disassembled perspective view which shows the structure of the thread trimming device 30a of the sewing machine of other embodiment in this invention. It is a perspective view which shows the structure of the thread trimming apparatus 1 of a prior art sewing machine.

  1 is a system diagram showing a configuration of a thread trimming device 30 of a sewing machine according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the thread trimming device 30 of a sewing machine, and FIG. 2 is a perspective view of a multi-needle chain stitch sewing machine 31 to be obtained. FIG.

  The thread trimming device 30 of the sewing machine according to this embodiment includes a thread tension adjusting unit 33, a movable knife 35, a swing arm 38, a cam member 40, a driving unit 41, a first link unit 42, and a second link unit 43.

  The thread tension adjusting means 33 is provided on the upper part of the sewing machine main body 32 in the multi-needle chain stitch sewing machine 31, and a plurality (3 in the present embodiment) of needle threads A1, A2, A3 (in a collective term, “needle thread”). A ”), a clamped state in which the upper decorative yarn B and the looper yarn C are clamped to apply tension to each needle thread A, the upper decorative yarn B, and the looper yarn C, and a clamped state in which the clamped state is released. It is configured to be switchable to either one of the arrival release states.

  The movable knife 35 moves forward in the direction of an arrow B11 that is close to the needle drop position P below the needle plate 34 (hereinafter may be referred to as “advance direction B11”), and moves away from the needle drop position P. The needle thread A and the looper thread C are cut by moving backward in the direction of the arrow B12 (hereinafter sometimes referred to as “reverse direction B12”).

  One end of the swing arm 38 is connected to the sewing machine body 32 by a first pin 36 so as to be angularly displaceable, and a follower 37 is provided at an intermediate portion between the other end and the one end.

  The cam member 40 is formed with a long hole 39 into which the follower 37 is movably fitted, and the swinging arm 38 is angularly displaced upward by the displacement of the cam member 40 in the direction of the arrow A11. The swing arm 38 is angularly displaced downward by displacement in the A12 direction.

  The first link means 42 transmits the displacement of the other end portion of the swing arm 38 to the yarn tension adjusting means 33, and moves the yarn tension adjusting means 33 from the pinched state to the pinching released state. Operate or operate from the pinching release state to the pinching state.

  The second link means 43 transmits the driving force of the driving means 41 to the movable knife 35 and angularly displaces the movable knife 35 in the forward direction B11 and the reverse direction B12.

  The yarn tension adjusting means 33 includes a substrate 50 and a plurality (five in the present embodiment) of sandwiching tools 51 provided at intervals in the longitudinal direction perpendicular to the plane of FIG. Each clamping tool 51 is provided with a cylindrical holding piece 52 fixed to the substrate 50, and an operation piece provided on the holding piece 52 and provided with a clamping release pin 53 that is inserted through the holding piece 52 and protrudes to the back side. 54, and between the operation piece 54 and the holding piece 52, the needle thread A, the upper decoration thread B, and the looper thread C are clamped with a clamping force according to the operation amount of the operation piece 54, and the needle thread A, a pair of sandwiching plates 55a and 55b for applying desired tension to the upper decorative yarn B and the looper yarn C, and the holding piece 52 are attached to the needle yarn A, the upper decorative yarn B and the looper yarn C. A pair of through-holes 56a and 56b, respectively, and a thread guide piece 57 formed therein.

  The substrate 50 is integrally provided with a yarn path guide portion 59 formed with a pair of thread insertion holes 58a and 58b through which the needle thread A, the upper decoration thread B, and the looper thread C are respectively inserted. Provided. Each needle thread A, upper decoration thread B and looper thread C are wound around a winding reel or bobbin (not shown), and each needle thread A, upper decoration thread B and looper thread C are connected to the yarn path guide portion 59. The thread insertion holes 58a and 58b are inserted into the thread guide holes 57, and one thread insertion hole 58a of each thread guide piece 57 is inserted from the front side to the back side, and then the other thread insertion hole 58b is inserted from the back side to the front side. Is done.

  Each needle thread A, upper decoration thread B, and looper thread C inserted through the thread insertion holes 58a, 58b of the yarn path guide portion 59 pass through one through hole 56a of each thread guide piece 57 from the back side to the front side. A plurality of (5 in the present embodiment) yarn paths that are inserted and pass between the respective sandwiching plates 55a and 55b, are inserted through the other through hole 56b from the front surface side to the back surface side, and are provided on the upper portion of the sewing machine body 32. The needle threads A are inserted through the through holes formed in the guide members 61 to 65, the needle threads A are inserted into the thread holes of the needles S, and the upper decorative thread B is inserted into the through holes 67 of the yarn path fitting 66.

  Further, the looper yarn C is inserted through the thread insertion holes 58a and 58b of the yarn path guide portion 59, and is inserted through one through hole 56a of the yarn guide piece 57 from the back side to the front side, and between the sandwiching plates 55a and 55b. The other through-hole 56b is inserted from the front surface side to the back surface side, and is guided from the looper yarn loosening portion 69 to the looper 75 through the looper yarn guide pieces 70 to 74.

  The cam member 40 has a first cam surface 81 that guides the follower 37 when the cam member 40 moves in the one direction A11 to an inner peripheral portion facing the elongated hole 39, and the follower 37 to the cam member. A second cam surface 82 that is guided when the 40 moves in the other direction A12 is formed in parallel to bend downward from the horizontal toward the other direction A12.

  The driving means 41 includes an electromagnetic solenoid 83, a connecting tool 85 fixed to the plunger 84 of the electromagnetic solenoid 83, a connecting shaft 86 having one end fixed to the connecting tool 85, and the other end of the connecting shaft 86. The connecting block 87 to be fixed, the interlocking shaft 88 whose one end is fixed to the connecting block 87, the interlocking shaft 88 is inserted, and the interlocking shaft 88 is moved in the direction of the arrows A11 and A12 in the axial direction on the other end side. A guide member 89 that is freely held, and a bracket 79 that holds the electromagnetic solenoid 83 and the interlocking shaft 88 and is fixed to the back surface of the sewing machine main body 32.

  The interlocking shaft 88 is attached with a return assisting spring 100 that applies a spring force for returning the interlocking shaft 88 in the direction of the arrow A12 from the state in which the interlocking shaft 88 is displaced in the direction of the arrow A11. In another embodiment of the present invention, an electric motor such as a servo motor may be used instead of the electromagnetic solenoid 83.

  The guide member 89 has a guide tube portion 90 through which the interlocking shaft 88 is inserted, and a plate-like flange portion 91 protruding from the guide tube portion 90, and one end portion of the swing arm 38 is connected to the flange portion 91. The first pin 36 is connected to be angularly displaceable.

  The first link means 42 has a first link member 94 whose one end disposed below is connected to the other end of the swing arm 38 by a second pin 92 so as to be angularly displaceable, and one end is a first. The second link member 96 is connected to the other end portion disposed above the link member 94 by a third pin 95 so as to be angularly displaceable.

  The other end portion of the second link member 96 is fixed to a rotating shaft 97 arranged substantially horizontally, and the rotation releasing shaft 97 has a pinch release pin of each pinching tool 51 of the yarn tension adjusting means 33. A pressing piece 99 for pressing 53 is fixed. When the pressing piece 99 presses the clamping release pin 53, the clamping force of each pair of clamping plates 55a and 55b of each clamping tool 51 is released, and each needle thread A, upper decoration thread B and looper are released. The tension of the thread C is released.

  The second link means 43 connects the third link member 101, the fourth link member 102, the fifth link member 103, and one end of the third link member 101 to the connecting block 87 so as to be angularly displaceable. A fourth pin 104, a fifth pin 105 that connects the other end of the third link member 101 and one end of the fourth link member 102 so as to be angularly displaceable, and the other end of the fourth link member 102 and the fifth link A sixth pin 106 that connects the one end of the member 103 so as to be angularly displaceable, a seventh pin 107 that connects an intermediate portion between both ends of the fourth link member 102 to the sewing machine body 32 so as to be angularly displaceable, and a fifth It includes an eighth pin 108 that connects the other end portion of the link member 103 and the intermediate portion of the movable knife 35 so as to be angularly displaceable.

  One end of the movable knife 35 is connected to the back surface of the needle plate 34 by a ninth pin 109 so as to be angularly displaceable. The first to ninth pins 36, 92, 95, 104 to 109 may be realized by pin bolts, for example. At the other end of the movable knife 35, a needle thread hook 35a and a looper thread hook 35b are provided on the ninth pin 109 side which is the center of angular displacement.

  FIG. 4 is a view for explaining the operation of the thread trimming device 30 of the sewing machine. FIG. 4 (1) shows a state immediately before the movable knife 35 enters the right needle thread A1 loop, and FIG. 4 shows a state in which the right needle thread A1 is pushed and spread by the outer peripheral part of the needle thread hook 35a, and FIG. FIG. 4 (4) shows a state in which the right needle thread A1, the central needle thread A2, and the left needle thread A3 are cut without resisting the force of spreading by the needle thread hook 35a. FIG. 4 (5) shows a state in which C has passed over the outer periphery of the needle thread hook 35a and is fitted into the thread cutting blade. FIG. 4 (5) shows that the movable knife 35 is normally positioned between the loops of the needle thread A1 to A3 and the looper thread C. Indicates the state of entry. Here, the needle threads A1 to A3 and the looper thread C that are cut by the movable knife 35 will be described, and the description of the upper decoration thread B that the movable knife 35 does not cut is omitted.

  In the above-described thread trimming device 30 of the sewing machine, the thread tension adjusting means 33 provided on the upper part of the sewing machine body 32 sandwiches the needle threads A1 to A3, the upper decoration thread B and the looper thread C, and these needle threads. In the clamped state in which tension is applied to A1 to A3, the upper decorative yarn B, and the looper yarn C, as shown in FIG. 4 (1), each needle S (see FIG. 3) is stopped at approximately the top dead center. The movable knife 35 moves forward in the direction of the arrow B11 close to the needle drop position P below the needle plate 34, and the right needle thread A1 is moved by the outer periphery of the needle thread hook 35a as shown in FIG. It is pushed out.

  At this time, the timing for releasing the clamped state of the needle threads A1 to A3 and the looper thread C of the thread tension adjusting means 33 by the thread trimming device 30 and the timing of the forward / backward movement of the movable knife 35 are optimally timed. If the clamped state is maintained, the movable knife 35 moves forward in the direction of the arrow B11 and spreads the needle thread loop in a state in which the tension at the time of sewing is applied to the needle threads A1 to A3. At this time, if the thread tension adjusting device 33 does not release the clamped state of the needle threads A1 to A3 and the looper thread C at an appropriate timing, the right needle thread A1 is a needle thread hook as shown in FIG. It will be cut without resisting the spreading force by the outer periphery of 35a. Further, the center needle thread A2 and the left needle thread 3 are pushed and spread by the outer periphery of the needle thread hook 35a, and the looper thread C is pushed onto the outer periphery of the needle thread hook 35a.

  When the movable knife 35 further advances in the direction of the arrow B11, as shown in FIG. 4 (4), the center needle thread A2 and the left needle thread A3 cannot resist the force of spreading by the outer periphery of the needle thread hook 35a. After being cut, the looper thread C passes over the outer periphery of the needle thread hook 35a and fits into the thread cutting blade.

  Thus, when the needle threads A1 to A3 are cut with the thread tension adjusting device 33 held between the respective threads, the tension of the needle threads A1 to A3 is suddenly released, and the tension is adjusted by the reaction. It is pulled back to the device side. As a result, the length from the thread hole of the needle to the cut end of the cut needle thread is shortened, and tension is applied again for the next sewing, and when the needle moves up and down, the needle thread becomes threaded. This causes a problem that the sewing machine cannot be sewn smoothly. When the looper thread C is cut by the thread cutting blade portion of the needle thread hook 35a as described above, the cut end of the looper thread C connected to the loop hole of the looper is retracted with the retracted movable knife 35 and thread holding spring (not shown). And the looper thread C comes out of the looper 75 when the next sewing operation is started.

  In order to prevent such a problem, the long hole 39 is formed in the cam member 40, the first and second cam surfaces 81 and 82 are formed on the inner peripheral surface facing the long hole 39, and the follower 37 is formed in the long hole 39. The first and second cam surfaces 81 and 82 are forcibly guided to follow and the timing of releasing the clamping of the yarn tension adjusting means 33 by the yarn trimming device 30 is determined by the movable knife 35 in the direction of the arrow B11. As shown in FIG. 4 (5), the movable knife 35 can release the clamped state of the needle threads A1 to A3 and the looper thread C at the optimal timing. After being relaxed, the needle threads A1 to A3 and the looper thread C can be cut.

  Accordingly, each needle thread A1 to A3 can be set to an appropriate length from the thread hole of each needle S, and the looper thread C can be held by a movable knife and a thread presser spring (not shown). This prevents the thread from coming off at the start of the sewing operation and prevents the above-described problems.

  In such a thread trimming device 30 of the present embodiment, a follower 37 is provided at an intermediate portion between one end and the other end of the swing arm 38, and the follower 37 is inserted into the elongated hole 39 of the cam member 40. In a state of being movably fitted, the swing arm 38 is angularly displaced in one direction by the displacement of the cam member 40 in one direction A11, and the swing arm 38 is moved by the displacement of the cam member 40 in the other direction A12. Since it can be angularly displaced in the other direction, the swing arm 38, the first link member 94, and the second link member 96 are interlocked by the displacement in the one direction A11 and the other direction A12 of the cam member 40, and with high responsiveness. The thread tension adjusting means 33 is moved from either the clamped state or the clamped release state to the other, and the movable knife 35 is clamped between the needle thread A and the looper thread C with high accuracy at an optimal timing during the forward movement. It can be released.

  FIG. 5 is an exploded perspective view showing a configuration of a thread cutting device 30a for a sewing machine according to another embodiment of the present invention. The parts corresponding to those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted to avoid duplication. The thread trimming device 30a of the sewing machine of this embodiment includes a thread tension adjusting means 33, a movable knife 35, a follower guide member 121, a cam member 40, a driving means 40, a first link means 42, and a second link. Means 43.

  The follower guide member 121 is fixed to the bracket 79, allows displacement of the follower 37 in a first direction J1 and a second direction J2 opposite to the first direction J1, and allows the follower 37 to move in the second direction J1. A follower guide 120 is provided to prevent displacement in the directions K1, K2 intersecting the first and second directions J1, J2. Here, the predetermined first direction J1 corresponds to the direction in which the yarn tension adjusting means 33 is operated from the pinched state to the pinching released state, and the predetermined second direction J2 is the yarn tension adjusting means 33. This corresponds to the direction of operation from the pinching release state to the pinching state.

  The cam member 40 is formed with a long hole 39 into which the follower 37 is movably fitted. By displacement in the arrow K1 direction, the follower 37 is displaced in the first direction J1 and in the arrow K2 direction. The displacement of the follower 37 is displaced in the second direction J2.

  The first link means 42 transmits the displacement of the other end of the swing arm 38 to the yarn tension adjusting means 33, and operates the yarn tension adjusting means 33 from the clamped state to the clamp release state. Or operating from the clamping release state to the clamping state.

  The second link means 43 transmits the driving force of the driving means 41 to the movable knife 35 and displaces the movable knife 35 in the forward direction B11 and the reverse direction B12. In the present embodiment, the first link means 42 is realized by a first link member 94. The cam member 40 is formed integrally with the other end of the swing arm 38 whose one end is pin-coupled to the flange 91 of the guide member 89 by the first pin 36.

  In such a thread trimming device 30a of the sewing machine, the arrow that allows the follower 37 to be displaced in the first direction J1 and the second direction J2 determined in advance by the follower guide member 121 and intersects the first and second directions J1 and J2. The displacement in the direction of the symbols K1 and K2 is prevented, and the follower 37 is movably fitted in the long hole 39 of the cam member 40. The displacement of the cam member 40 in the one direction K1 causes the follower 37 to move to the first direction. Displacement in the direction J1 and displacement of the follower 37 in the second direction J2 by the displacement of the cam member 40 in the other direction K2 switch between the pinching state and the pinching release state of the yarn tension adjusting means 33 with high accuracy. be able to.

  In addition, the follower 37 is fitted into the long hole 39 of the cam member 40, and the follower 37 is constituted by the first cam surface 81 and the second cam surface 82. Even if an impact force acts on the first and second link means 42 and 43 by the prepared abutment, the follower 37 abuts on one or both of the first and second cam surfaces 82, and the yarn tension adjusting means It is possible to prevent the second link member 96 closest to 33 from being displaced and the pinching state of the needle thread A, the upper decoration thread B, and the looper thread C being released.

30, 30a Thread trimming device for sewing machine 31 Multi-needle chain stitch machine 32 Sewing machine body 33 Thread tension adjusting means 34 Needle plate 35 Movable knife 36 First pin 37 Follower 38 Swing arm 39 Long hole 40 Cam member 41 Driving means 42 First Link means 43 Second link means 50 Substrate 51 Clamping tool 52 Holding piece 53 Clamping release pin 54 Operation piece 55a, 55b Clamping plate 56a, 56b; 67 Through hole 57 Thread guide piece 58a, 58b Thread insertion hole 59 Yarn path Guide part 61-65 Yarn path guide member 66 Yarn path metal fitting 75 Looper 81 First cam surface 82 Second cam surface 83 Electromagnetic solenoid 84 Plunger 85 Connection tool 86 Connection shaft 87 Connection block 88 Interlock shaft 89 Guide member 90 Guide tube 91 Flange A: A1-A3 Needle thread B Top decoration thread C Looper thread

Claims (3)

Switched to either the clamped state where the needle thread and looper thread are clamped and tension is applied to the needle thread and looper thread, and the clamped release state where the clamped state is released. Possible thread tension adjusting means;
A movable knife that cuts the needle thread and the looper thread by moving forward in the direction close to the needle drop position below the needle plate and moving backward in the direction away from the needle drop position;
One swinging end is connected to the sewing machine body so as to be angularly displaceable, and a swing arm provided with a follower at an intermediate portion between the other end and the one end,
A long hole into which the follower is movably fitted is formed, and the swing arm is angularly displaced in one direction by displacement in one direction, and the swing arm is angularly displaced in another direction by displacement in the other direction. Members,
Drive means for displacing the cam member in the one direction and the other direction;
The displacement of the other end of the swing arm is transmitted to the thread tension adjusting means, and the thread tension adjusting means is operated from the clamped state to the clamp release state or from the clamp release state to the clamp. First link means for operating to a wearing state;
A sewing machine thread trimming apparatus comprising: second link means for transmitting a driving force of the driving means to the movable knife and moving the movable knife forward and backward. Switched to either the clamped state where the needle thread and looper thread are clamped and tension is applied to the needle thread and looper thread, and the clamped release state where the clamped state is released. Possible thread tension adjusting means;
A movable knife that cuts the needle thread and the looper thread by moving forward in the direction close to the needle drop position below the needle plate and moving backward in the direction away from the needle drop position;
A displacement of the follower in a direction crossing the first and second directions, which is fixed to the sewing machine body and allows the displacement of the follower in a second direction opposite to the first direction and the first direction. A follower guide member provided with a follower guide part for preventing
A long hole is formed into which the follower is movably fitted, and the follower is displaced in the first direction by displacement in one direction along the intersecting direction, and by displacement in the other direction along the intersecting direction. A cam member for displacing the follower in the second direction;
Drive means for displacing the cam member in the one direction and the other direction;
The displacement of the other end of the swing arm is transmitted to the yarn tension adjusting means, and the yarn tension adjusting means is operated from the clamped state to the clamp release state or from the clamp release state to the clamp First link means for operating to a state;
A sewing machine thread trimming apparatus comprising: second link means for transmitting a driving force of the driving means to the movable knife and moving the movable knife forward and backward.   A first cam surface that guides the follower when the cam member moves in the one direction and an inner portion of the cam member facing the elongated hole, and the follower in the other direction of the cam member. The thread trimming device for a sewing machine according to claim 1, wherein a second cam surface is formed to guide when moving.

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