JP4294435B2 - sewing machine - Google Patents

Description

  The present invention relates to a sewing machine.

2. Description of the Related Art Conventionally, there is a single thread chain stitch sewing machine that sews a button on a cloth of clothes by a single thread ring stitch. This single thread chain stitch sewing machine is provided with a thread shifting member, and for example, the one shown in FIG. 10 is known. Here, FIG. 10A is a plan view, FIG. 10B is a front view, and FIG. 10C is a side view. Immediately before the sewing needle 81 reaches the bottom dead center, when the tip of the sewing needle 81 is substantially flush with the upper surface of the thread gathering member 82, the thread gathering member 82 moves in the A direction. Two sewing threads are hooked by the thread gathering portion 82a at the tip, and gathered to the ridgeline 82b at the deepest part of the yarn gathering portion 82a. At this time, the two sewing threads 83 a and 83 b gathered together are retracted to the side of the vertical movement path in a posture inclined with respect to the vertical movement path of the sewing needle 81. Therefore, in a state where the upper portions of the two sewing threads 83a and 83b are brought close to each other, the sewing needle 81 is displaced to the side of the vertical movement path, whereby the sewing needle 81 is moved to the two sewing threads 83a and 83b. It is made to prevent falling in between (for example, refer patent document 1).
Japanese Patent Laid-Open No. 11-19361

  By the way, the yarn shifting member 82 is moved by a necessary minimum distance in order to eliminate unnecessary movement. In other words, even when the yarn moving member 82 moves in the A direction, it moves only to the extent that the vertical movement path of the sewing needle 81 is barely displaced. For this reason, when the tip of the sewing needle 81 is bent by the tension of the sewing threads 83a and 83b, there is a problem in that when the sewing needle 81 is lowered, the tip contacts the thread shifting member 82 and the sewing needle 81 is broken.

  Therefore, an object of the present invention is to provide a sewing machine that prevents the tip from coming into contact with the thread gathering member when the sewing needle is lowered.

In order to solve the above problems, the invention described in claim 1
A sewing needle that reciprocates up and down;
A looper that picks up a loop of sewing thread when the sewing needle ascends from bottom dead center;
Thread gathering arranged above the looper and gathering together the middle portions of the two sewing threads stretched between the looper and the fabric when the sewing needle descends and retracts from the vertical movement path of the sewing needle And a clamping part for sandwiching one of the sewing threads passed through the needle hole of the sewing needle between the sewing needle and the sewing needle when the sewing needle is raised, and passing through the predetermined movement path from the standby position. A yarn gathering member that moves to a yarn gathering position where yarn gathering by the gathering unit and yarn clamping by the clamping unit are performed;
A sewing machine comprising: a drive mechanism that moves the yarn shifting member along the predetermined movement path;
The drive mechanism moves the thread gathering member to the thread gathering position before the tip of the descending sewing needle reaches the thread gathering member, and then the tip of the sewing needle is moved to the side of the thread gathering member. Is moved to an isolation position that is isolated from the vertical movement path of the sewing needle before passing the direction, and contact with the sewing needle is prevented, and further, the sewing needle is moved to the thread shifting position before the sewing needle is raised from the bottom dead center. By returning, the sewing thread passed through the needle hole of the sewing needle is clamped .

  According to the first aspect of the present invention, the drive mechanism moves the thread gathering member to the thread gathering position before the tip of the descending sewing needle reaches the thread gathering member, and then the tip of the sewing needle moves to the thread gathering position. Before passing the side of the shifting member, it is moved to an isolation position where it is isolated from the vertical movement path of the sewing needle, and further returned to the thread shifting position before the sewing needle rises from the bottom dead center.

According to the first aspect of the present invention, the drive mechanism moves to the thread gathering position before the tip of the sewing needle that descends the thread gathering member reaches the thread gathering member, and then the tip of the sewing needle moves to the yarn gathering. Before passing the side of the member, the sewing needle is moved to an isolation position to be isolated from the vertical movement path of the sewing needle, and further returned to the thread shifting position before the sewing needle is lifted from the bottom dead center.
Therefore, when the sewing needle is lowered, the drive mechanism forms a gap between the tip of the sewing needle and the thread pulling member when the tip of the sewing needle passes the side of the thread pulling member. Therefore, even if the tip of the sewing needle descends in a bent state due to the tension of the sewing thread, the tip will pierce the fabric through the gap, so that it is possible to prevent the sewing needle from coming into contact with the thread gathering member. it can. In addition, when the sewing needle is raised, the drive mechanism is such that a part of the sewing thread passed through the needle hole of the sewing needle is sandwiched between the sewing needle and the thread pulling member, and the sewing needle rises even when the sewing needle is raised. The sewing thread near the needle hole is loosened. Therefore, since it becomes easy to form a loop of the sewing thread, it is possible to reduce sewing defects due to stitch skipping, greatly improve workability, and further improve product quality.

Hereinafter, the best mode of a sewing machine according to the present invention will be described in detail with reference to the drawings. In this embodiment, as an example of the sewing machine, a button sewing machine that performs single-thread ring stitching will be described as an example.
<Configuration of sewing machine>
As shown in FIGS. 1 to 4, a button sewing machine (hereinafter referred to as a sewing machine) 100 includes a sewing needle 1 that reciprocates up and down, and a loop of sewing threads t1 and t2 when the sewing needle 1 rises from the bottom dead center. The looper 2 that picks up the sewing needle and the middle portions of the two sewing threads t1 and t2 that are stretched between the looper 2 and the fabric when the sewing needle 1 descends are gathered together and retracted from the vertical movement path of the sewing needle 1. It has a thread gathering part 32 and a clamping part 34 that sandwiches one of the two sewing threads t1, t2 between the sewing needle 1 when the sewing needle 1 is raised, and passes a predetermined movement path from the standby position. A yarn gathering member 3 that moves to a yarn gathering position where yarn gathering by the yarn gathering portion 32 and yarn clamping by the pinching portion 34 are performed, a drive mechanism 4 that moves the yarn gathering member 3 along a predetermined movement path, and the like It has.

As shown in FIG. 1, a needle hole 11 is formed at the tip of the sewing needle 1, and the sewing threads t <b> 1 and t <b> 2 are passed through the needle hole 11.
The looper 2 includes a first thread hook 2a having a claw-shaped tip, a second thread hook 2b having a curved outer peripheral surface, and a shaft portion 2c. Internally, it is attached to the front end of the looper shaft via the shaft portion 2c, and when the sewing machine 100 is operated, it rotates in the counterclockwise direction by the rotation of the looper shaft and operates together with the sewing needle 1 to form a seam. is there.

  The thread shifting member 3 is interposed between a needle plate (not shown) of the sewing machine 100 and the looper 2 and performs a leftward / rightward movement in the direction AB, and when the sewing needle 1 is lowered. , Once in the D direction, proceed in the A direction, and the lower end of the sewing needle 1 by hooking the middle part of the two sewing threads (loop part) with the tip part stretched between the fabric and the looper 2 Further, the sewing needle 1 is configured to retreat in an oblique direction between the B direction and the C direction when the sewing needle 1 is raised. Further, as shown in FIG. 2, an oval guide hole 31 that is long in the width direction, that is, the AB direction is formed in the proximal end portion of the yarn moving member 3.

Further, the thread shifting member 3 hooks the middle portions of the two sewing threads (loop portions) t1 and t2 stretched between the fabric and the looper 2 so as to be moved to the side where the sewing needle 1 is lowered. However, the two sewing threads t1 and t2 located above the thread shifting member 3 are arranged so as to closely contact each other when the middle portions of the two sewing threads t1 and t2 are hooked and gathered. Yes. In other words, the yarn gathering member 32 is formed with a yarn gathering portion 32 in which a depression is formed in the direction in which the sewing threads t1 and t2 are gathered.
Further, the thread shifting member 3 guides the lowering of the sewing needle 1 when the sewing needle 1 is lowered, and the thread shifting member 3 is connected to the sewing needle 1 so that a thread loop is reliably formed when the sewing needle 1 is raised. A clamping part 34 for clamping the sewing thread t1 therebetween is provided.
Further, both side end surfaces and the lower surface of the yarn moving member 3 are supported by the guide plate 7. The guide plate 7 is fixed in the longitudinal direction of the yarn moving member 3, that is, the CD direction, and is movable in the AB direction. Further, the yarn shifting member 3 is attached to the guide plate 7 so as to be slidable in the AB direction.
Further, as shown in FIGS. 2 to 4, a rotary shaft 22 is disposed below the yarn shifting member 3 so as to be parallel to the CD direction and rotatable about the axis. The sewing needle 1 is rotated in conjunction with the vertical movement of the sewing needle 1 by a drive source (not shown). Further, as shown in FIG. 4, the triangular cam 9 is attached to the distal end portion of the rotating shaft 22 in an eccentric state. Therefore, when the triangular cam 9 is rotated by the rotary shaft 22, the guide plate 7 is moved in the AB direction.

As shown in FIGS. 3 and 4, the drive mechanism 4 includes a guide hole 31 formed at the proximal end portion of the yarn moving member 3, a rotating member 5 that rotates while being supported by the rotating shaft 22, and a guide hole 31. And a pin member 6 that engages with the rotating member 5.
The rotating member 5 is formed in a cylindrical shape, and a wave-like groove 51 is formed on the outer peripheral surface along the rotation direction. A curved portion 52 that slightly swells on the distal end side of the proximal end portion of the yarn moving member 3 is formed in a part of the groove portion 51. Although details will be described later, the curved portion 52 moves the thread pulling member 3 so as to be isolated from the vertical movement path of the sewing needle 1 when the sewing needle 1 is lowered.
The pin member 6 is provided on the other end portion of the plate member 8 whose one end portion is rotatably fixed to the sewing machine body so as to protrude perpendicularly from the upper and lower surfaces of the plate member 8 to the upper and lower surfaces of the plate member 8, respectively. Yes. The pin member 6 on the lower surface side of the plate material 8 is engaged with the groove portion 51 of the rotating member 5, and the pin member 6 on the upper surface side of the plate material 8 is engaged with the guide hole 31 of the yarn shifting member 3, The guide hole 31 can be freely moved.

<Single thread chain stitch method>
Here, a method of sewing buttons on the fabric by single-thread ring stitching will be described with reference to FIG. First, when the sewing needle 1 in one hole of the button starts to move slightly upward from its bottom dead center position, a loop portion of the sewing threads t1, t2 is formed on the back side of the tip of the sewing needle 1. The tip of the first yarn hooking portion 2a of the looper 2 enters the loop portion. At this time, the loop portion of the sewing threads t1 and t2 in the previous step is hung between the first yarn hooking portion 2a and the second yarn hooking portion 2b. It is going to the left to bring the loop part.

  Next, when the sewing needle 1 rises from one hole of the button, the looper 2 widens the loop portions of the sewing threads t1, t2 with the first thread hook portion 2a, and the loop portion in the previous step is hooked with the first thread hook. Remove from the rear side of the part 2a. At this time, the thread pulling member 3 is retracted to the right as the sewing needle 1 is raised.

  Subsequently, when the sewing needle 1 descends from the top dead center position, the button and the fabric C are fed by the feed mechanism provided inside the sewing machine, and the other hole of the button is placed directly below the sewing needle 1. Will be located. At this time, the looper 2 rotates counterclockwise to move the loop portions of the sewing threads t1, t2 from the first thread hook 2a to the second thread hook 2b. At this time, the previously removed loop portion of the previous process is pulled upward and tightened. At the same time, the yarn gathering member 3 moves leftward so as to catch the middle portion of the loop portion and bring it to a position that does not hinder the lowering of the sewing needle 1.

  Next, as the sewing needle 1 descends and enters the other hole of the button, the loop of the sewing threads t1 and t2 in the previous process is tightened to form a knot (seam). At the same time, the loop portions of the sewing threads t1 and t2 move from the first yarn hooking portion 2a of the looper 2 to the second yarn hooking portion 2b side, and obliquely from the lower surface of the fabric C to the yarn shifting member 3. It is in a stretched state. Next, when the sewing needle 1 that has entered the other hole of the button begins to move upward slightly from its bottom dead center, a new loop portion is newly formed on the back side of the tip of the sewing needle 1, Thereafter, sewing is performed in the same manner as described above.

<Operation of the thread-feeding member>
Next, the operation of the yarn gathering member 3 by the drive mechanism 4 will be described with reference to FIGS. FIG. 6 is a diagram schematically showing the movement locus of the yarn gathering portion 32 of the yarn gathering member 3 synthesized based on the shapes of the groove portion 51 of the rotating member 5 and the outer peripheral surface of the triangular cam 9. FIG. 7 is a diagram schematically showing the height position of the tip of the sewing needle 1 from the yarn gathering member 3 corresponding to the movement locus of the yarn gathering portion 32 of the yarn gathering member 3 in FIG. In FIG. 6, for easy understanding, the position of the yarn shifting member 3 at the positions P5 and P2 (P4) is indicated by a one-dot chain line. Further, the sewing needle 1 moves up and down at the position of P6 as shown in FIG.

  First, when the sewing needle 1 is located at the top dead center, the yarn gathering portion 32 of the yarn gathering member 3 is located at P5 in FIG. 6, and the sewing needle 1 is located at the top dead center at P5 in FIG. When the rotary shaft 22 rotates with the lowering of the sewing needle 1 from the top dead center, the pin member 6 on the lower surface side of the plate material 8 engages with the groove portion 51 and moves in the D direction. While the pin member 6 slides on the guide hole 31, the yarn gathering member 3 is moved in the direction D, and the yarn gathering portion 32 of the yarn gathering member 3 is moved to P1. The position of P1 is a position where the tip 33 of the thread gathering member 3 can cross the vertical movement path of the sewing needle 1 when the yarn gathering member 3 moves in the A direction thereafter. In the movement of the yarn gathering portion 32 from P5 to P1, the triangular cam 9 is formed so that the distance from the outer peripheral surface to the axis of the rotary shaft 22 is constant. During the movement to P1, the movement in the AB direction by the triangular cam 9 is not performed.

Further, when the rotary shaft 22 rotates as the sewing needle 1 descends, the guide member 7 moves in the A direction due to the eccentricity of the triangular cam 9, and this movement causes the yarn feeder 3 to move in the A direction. Then, the tip 33 of the thread shifting member 3 crosses under the sewing needle 1 indicated by P6 during this movement, and hooks two sewing threads t1 and t2 that are stretched between the fabric and the looper 2. Gather together. Further, the movement of the yarn gathering member 3 in the A direction is continued until the yarn gathering portion 32 reaches P2 (yarn gathering position). The two sewing threads t1 and t2 spanned between the fabric and the looper 2 by the movement of the yarn gathering portion 32 from P1 to P2 are gathered together in the middle of the yarn gathering portion 32, and the position of P2 Moved to. By the movement of the thread gathering portion 32 from P1 to P2, the sewing needle 1 is withdrawn from the vertical movement path of the sewing needle 1, and the sewing needle 1 is prevented from entering between the sewing threads t1 and t2. And can be sewn to the fabric reliably.
The movement of the yarn feeder 32 from P1 to P2 is not performed by the groove 51 of the rotating member 5 in the CD direction of the plate member 8 but is performed only by the rotation of the triangular cam 9.

  At the moment when the thread gathering portion 32 is positioned at P2, as shown in FIG. 7, the sewing needle 1 is still in the position of lowering, and the tip of the sewing needle 1 is positioned above the thread gathering member 3 (for example, About 1 cm above). Thereafter, the sewing needle 1 further descends and moves to a position (position P3 shown in FIG. 7) that is substantially flush with the upper surface of the thread pulling member 3. While the sewing needle 1 is lowered from the position P2 to the position P3, the thread pulling member 3 moves backward in the C direction.

Here, the operation of the yarn gathering member 3 when the yarn gathering portion 32 which is a characteristic part of the present invention draws a locus from P2 to P3 and from P3 (isolation position) to P4 (yarn gathering position) will be described.
As shown in FIG. 8, when the sewing needle 1 is further lowered from the above-mentioned lowering position by the drive mechanism provided in the sewing machine 100, the rotary shaft 22 also rotates, and the tip of the sewing needle 1 is threaded. When passing through the side of the member 3 (position P3 shown in FIG. 7), that is, immediately before the tip and the upper surface of the yarn pulling member 3 are substantially flush, the pin member 6 on the lower surface side of the plate 8 is rotated by the rotating member 5. When the sewing needle 1 passes by the side of the thread gathering member 3 and the thread gathering member 3 starts to move backward in the direction C, the movement path of the sewing needle 1 and the thread gathering are started. The interval between the members 3 increases. The sewing needle 1 reaches the bottom dead center (position P4 shown in FIG. 7) immediately after the thread gathering portion 32 of the thread gathering member 3 is retracted to the position P3.

  Thereafter, as shown in FIGS. 7 and 8, while the sewing needle 1 reaches the bottom dead center from the side of the thread pulling member 3, the pin member 6 on the lower surface side of the plate member 8 is rotated by the rotation of the rotary shaft 22. It passes through the vicinity of the apex 52 a of the bending portion 52 of the rotating member 5, moves in the D direction, and finishes passing through the bending portion 52. Accordingly, the pin member 6 on the upper surface side of the plate member 8 advances the yarn gathering member 3 in the D direction, and before the sewing needle 1 is lifted from the bottom dead center, the yarn gathering portion 32 is again moved to the yarn gathering of P2 (P4). Returning to the position, the thread gathering member 3 is brought close to the sewing needle 1 and the clamping part 34 of the thread gathering member 3 so as to sandwich the sewing thread. As a result of this movement, the yarn moving portion 32 reaches the position P2 (P4) again. In this way, the sewing needle 1 and the pinching portion 34 of the thread pulling member 3 are brought close to each other so that the thread is pinched by the sewing needle 1 and the pinching portion 34, so that the lowering of the sewing needle 1 can be guided. When the sewing needle 1 is raised, a thread loop can be surely formed.

  During the movement in the CD direction of the yarn gathering member 3 from P2 to P4, the yarn gathering portion 32 is not moved in the AB direction by the triangular cam 9, and the movement of the yarn gathering member 3 is This is performed only by the rotation of the rotating member 5.

  Further, after the yarn gathering member 3 arrives at the position where the yarn gathering portion 32 is set to P2 (P4), it is moved in the B direction and the C direction by the rotation of the rotary shaft 22 as the sewing needle 1 is raised, and the sewing needle When 1 reaches the top dead center, the yarn gathering portion 32 arrives again at the position set to P5. The movement of the yarn feeder 32 from P2 (P4) to P5 is performed by combining the movement in the B direction by the triangular cam 9 and the movement in the C direction by the groove 51 of the rotating member 5.

  According to the sewing machine 100 according to the present invention, when the sewing needle 1 is lowered, the rotating member 5 rotates, so that the pin member 6 on the lower surface side of the plate material 8 is guided by the wave-like groove 51 and the thread-feeding member 3 is rotated. Moves up and down in the longitudinal direction. Here, the groove portion 51 is formed with a curved portion 52 that moves the pin member 6 on the lower surface side of the plate 8 toward the distal end side of the base end portion of the yarn gathering member 3 when the rotary member 5 rotates when the sewing needle 1 is lowered. Therefore, the pin member 6 on the lower surface side of the plate member 8 passes through the curved portion 52 during the rotation of the rotating member 5. When the pin member 6 on the lower surface side of the plate material 8 passes through the curved portion 52, the pin member 6 on the upper surface side of the plate material 8 moves backward along the longitudinal direction of the yarn gathering member 3 and guide holes 31 of the yarn gathering member 3. The pin member 6 on the upper surface side of the plate member 8 engaged with the threading member retracts the yarn gathering member 3 in the longitudinal direction. On the other hand, when the pin member 6 on the lower surface side of the plate material 8 has passed through the apex 52a of the curved portion 52, the pin member 6 on the upper surface side of the plate material 8 moves forward along the longitudinal direction of the yarn shifting member 3, The pin member 6 on the upper surface side of the plate member 8 engaged with the three guide holes 31 advances the yarn moving member 3 in the longitudinal direction.

  Therefore, when the sewing needle 1 is lowered, the drive mechanism 4 separates the thread gathering member 3 from the vertical movement path of the sewing needle 1 before the tip of the sewing needle 1 passes the side of the yarn gathering member 3. As a result, a gap is formed between the tip of the sewing needle 1 and the thread pulling member 3, and the tip pierces the fabric through the gap even when the tip is lowered while the tip is bent by the tension of the sewing thread. As a result, the sewing needle 1 can be prevented from coming into contact with the thread gathering member 3. Further, when the sewing needle 1 is raised, the drive mechanism 4 moves the thread-feeding member 3 in the vertical movement path of the sewing needle 1 so that a part of the sewing thread is sandwiched between the sewing needle 1 and the clamping part 34 of the thread-feeding member 3. Close. As a result, a part of the sewing thread passed through the needle hole of the sewing needle 1 is sandwiched between the sewing needle 1 and the thread pulling member 3 and does not rise even when the sewing needle 1 is raised. The sewing thread becomes loose. Therefore, since it becomes easy to form a loop of the sewing thread, it is possible to reduce sewing defects due to stitch skipping, greatly improve workability, and further improve product quality.

  Further, the drive mechanism 4 retracts the thread gathering member 3 along its longitudinal direction when the sewing needle 1 is lowered, and advances the thread gathering member 3 along its longitudinal direction when the sewing needle 1 is raised. That is, the drive mechanism 4 only needs to be configured to move the yarn gathering member 3 in the front-rear direction, so that the structure can be simplified.

  The present invention is not limited to the above embodiment. For example, instead of the rotating member 5 constituting the drive mechanism 4, the yarn moving member 3 may be moved backward or forward using another actuator such as a stepping motor. In addition, the present invention can be freely changed and improved without departing from the gist of the invention.

It is a perspective view which shows the principal part of the sewing machine which concerns on this invention. It is a top view which shows the principal part of the sewing machine shown in FIG. FIG. 2 is a perspective view of a rotating member in FIG. 1. It is a perspective view which shows a drive mechanism. It is a figure explaining the thread gathering member at the time of sewing, (a) is a front view, (b) is a side view. It is a top view which shows the movement locus | trajectory of the yarn gathering part of a yarn gathering member. It is a top view which shows the movement locus | trajectory of a sewing needle. It is a figure which shows the positional relationship of a sewing needle and a thread gathering member at the time of lowering of a sewing needle. It is a figure which shows the positional relationship of a sewing needle and a thread gathering member at the time of a raise of a sewing needle. It is an example of the sewing machine in a prior art, (a) is a top view, (b) is a front view, (c) is a side view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sewing needle 2 Looper 3 Thread gathering member 31 Guide hole 32 Thread gathering part 34 Nipping part 4 Drive mechanism 5 Rotating member 51 Groove part 52 Curved part 6 Pin member 100 Sewing machine

Claims (1)

A sewing needle that reciprocates up and down;
A looper that picks up a loop of sewing thread when the sewing needle ascends from bottom dead center;
Thread gathering arranged above the looper and gathering together the middle portions of the two sewing threads stretched between the looper and the fabric when the sewing needle descends and retracts from the vertical movement path of the sewing needle And a clamping part for sandwiching one of the sewing threads passed through the needle hole of the sewing needle between the sewing needle and the sewing needle when the sewing needle is raised, and passing through the predetermined movement path from the standby position. A yarn gathering member that moves to a yarn gathering position where yarn gathering by the gathering unit and yarn clamping by the clamping unit are performed;
A sewing machine comprising: a drive mechanism that moves the yarn shifting member along the predetermined movement path;
The drive mechanism moves the thread gathering member to the thread gathering position before the tip of the descending sewing needle reaches the thread gathering member, and then the tip of the sewing needle is moved to the side of the thread gathering member. Is moved to an isolation position that is isolated from the vertical movement path of the sewing needle before passing the direction, and contact with the sewing needle is prevented, and further, the sewing needle is moved to the thread shifting position before the sewing needle is raised from the bottom dead center. A sewing machine characterized by holding the sewing thread passed through the needle hole of the sewing needle by returning the sewing thread .

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