JPS6255436B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thread switching device for a sewing machine that can quickly and easily change a plurality of sewing threads using one thread take-up.

Changing the sewing thread on a sewing machine requires a lot of effort, and this has a large negative impact on efficiency, especially in assembly lines of industrial sewing.

Conventionally, there have already been multi-head shearing machines that have multiple thread holes in one thread take-up to quickly switch between multiple threads, but due to the structure, due to the increase in the weight of the thread take-up, etc. This also became a factor that hindered speed increases.

In addition, with this type of sewing machine, only one of the sewing needles in use works, and the other needles do not work, but all the threads move up and down as the thread take-up moves up and down. Therefore, there were problems such as thread tangles, etc., and the workers were visually bothered by the disturbance of the threads.

The present applicant has already filed an application for a technology (Japanese Patent Application No. 57-076262, hereinafter referred to as technology No. 1) that eliminates such drawbacks.

That is, only one thread selected from among the many threads is moved by one thread take-up, and the other threads are held in place near the top dead center. For this purpose, one thread take-up was provided, and a string was hung on the thread to move it up and down. and a first groove having a long groove for receiving the vertical movement of the thread threading portion of the thread take-up, is bent into an arc shape that is approximately the same as the locus of this movement, and is arranged at intervals in the projecting direction of the thread take-up. and a second thread holding plate, and a plurality of thread holding plates arranged in parallel between them, having the same vertical grooves as above, and bent in the same manner as the thread holding plate. .

The lower part of each of the thread holding plates forms a gap between the first and second thread holding plates, through which the thread passes, and one part of the gap is such that the thread can freely pass through. I kept it.

Therefore, the upper part of each of the thread holding plates moves to the first or second holding plate side simultaneously or individually, and when each thread is lifted by the thread take-up, the selected thread is removed. By holding the thread, it is possible to quickly change the thread.

The configuration of the present invention relates to an improvement of the technology mainly based on the main part of the technical configuration of item (A), in which threads other than the selected thread are clamped with surface pressure near the top dead center of the thread take-up. As such, frictional resistance means are provided on either the first or second yarn holding plate and both the first and second yarn holding plates. Therefore, the unselected threads are completely held between the joints, and the clamping function is not inhibited even by vibrations during operation of the sewing machine.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a side view of a sewing machine head equipped with a thread switching device of the present invention, and FIGS. 2 and 3 are a plan view and a front view thereof, respectively. In the figure, 5 is a thread tension device;
6 is a thread tension device support, 7 is a thread loosening shaft, 8 is a thread loosening operating arm, 9 is a thread loosening drive arm, 10 is a thread take-up support shaft, 1
1 is a balance crank, 12 is an upper shaft, 13 is a needle bar crank rod, 14 is a needle bar crank rod shaft, 15
16 is a thread hook, 16 is a needle bar holder, 17 is a needle bar, and 18 is a presser bar, and since these are the same as the conventional mechanisms, a detailed structural explanation will not be given.

Reference numeral 19 denotes a thread take-up, and a portion 19a on which the needle thread 20 is hung is formed into a fork as shown in FIG. The tip of the thread hooking part 19a of the thread take-up lever 19 is connected to a long groove 23 formed in the vertical movement direction of the thread thread take-up lever on the first and second thread holding plates 21 and 22.
a and 23b (see Fig. 1). Further, the first and first thread holding plates 21 and 22 are bent into an arc shape that is approximately the same as the trajectory of the vertical movement of the thread take-up lever 19, and the first thread holding plate 21 has an appropriate width l near the top dead center of the thread take-up. A curved protrusion 21a is formed, and both are spaced apart from each other in the protruding direction of the balance 19.

The first and second yarn holding plates 21 and 22, which are disposed with this interval, have the same groove as the holding plates,
and a first thread retaining plate 21 having a curved protrusion 24a which is bent in the same way and is wider and lower in height than the protrusion 21a of the first thread holding plate 21.
A second yarn presser plate 25 is disposed opposite to the thread presser plate 24 and the protrusion of the first yarn presser plate 24, and has a curved protrusion 25a that is wider and lower in height than the protrusion 24a. In addition, the projections 21a, 24a,
The R of the contact surface at the time of contact in each of 25a is the same and is centered at the same point. Therefore, the thread presser plate 2
4, 25 are provided with first and second thread holding plates 21, 2.
2 through spacers 26, 26, 26 with screws 27, and a gap 28 is formed through which the thread passes.

29 is a thread 20 extending from the thread tension device 5 to the thread hook 15
is a thread hanging bar on which the thread holding plate 24, 2 is hung.
A grooved cam plate 30 is provided on the lower side of the grooved cam plate 30 so as to be movable back and forth. A groove 31 having a shape as shown in FIG. 2 is formed in the grooved cam plate 30, and the groove 31 has a rising portion 22a of the second yarn holding plate 22, and the first and second yarn holding plates 24, 25. The rising portions 24b, 25b are inserted from below and engaged with the inclined cam surface of the groove 31.

Also, a thread switching lever 32 is provided at the other end of the grooved cam plate 30.
The upper ends of the lever 32 are connected to each other, and the lower part of the lever 32 is pivotally supported to a frame 35 by a stepped screw 34 via a disc spring 33. 36 is the frame 3 with the tightening screw 37.
With the positioning plate attached to 5, the thread switching lever 3
2 is a gap 38 between the positioning plate 36 and the frame 35
When the projection 32a provided on the lever 32 enters the notch 39 of the positioning plate 36, its position is fixed, and the lever 32 is inserted into the notch 39 of the positioning plate 36. When the knob 40 fixed to the top of the frame 32 is pressed, it tilts toward the frame 35 against the disc spring 33, and the protrusion 32a
is removed from the notch 39 and becomes slidable in the direction of the arrow, allowing the grooved cam plate 30 to be moved in the direction of the arrow.

Next, to explain the operation, first, the thread take-up 19 is positioned at the bottom dead center, the three threads 20 are taken out from the gap 28 in the part where the spacer 26 is located, and the thread take-up 19 is moved to the bottom dead center.
After hanging the thread above the thread hook 19a, pass it through the needle 17,
For example, the first and second thread presser plates 24 and 25 are shown in FIG.
When moved to the states shown in FIG. 5A and FIG. 2, the thread 20 in the middle is selected.

In this state, when the pedal of the sewing machine is depressed, the shaft 12 rotates (it stops when the pedal is released). Upper shaft 12
When the lever rotates, the thread take-up crank 11 rotates, and the needle bar 17 is rotated through the needle bar crank rod 13 and the rod shaft 14.
moves up and down. Also, the thread take-up 19 includes a needle bar crank rod 13, a slider 41, a rod 42, and a thread take-up support shaft 1.
The needle bar 17 swings up and down while being out of phase with the needle bar 17 via the needle bar 17. The middle thread selected by the vertical movement of the thread take-up 19 is pulled out and supplied to the needle for use in sewing, while the threads on both sides are lifted by the upward movement of the thread take-up 19, one of which is attached to the first thread holding plate 21. protrusion 2
1a and the protrusion 24a of the first thread holding plate 24, and the other between the second thread holding plate 22 and the protrusion 25a of the second thread holding plate 25 near the top dead center of the thread take-up 19. It does not move because it is held in place by the husband.

Next, push in the knob 40 to remove the protrusion 32a from the center notch 39, and move the thread switching lever 32 to the first
When turned to the left in the figure using the step screw 34 as a fulcrum, the grooved cam plate 30 moves to the position indicated by the solid line in Figure 4A, and the first and second thread presser plates 24 and 25 engage the groove 31 at the same time. Then, the rising portions 24b and 25b move to the position shown in FIG. 5B, release the left thread for sewing, and pinch the middle and right threads.

Next, when the thread switching lever 32 is turned to the right from the state shown in FIG. 1, the grooved cam plate 30 moves to the right as shown in FIG. 24b and 25b simultaneously move toward the first yarn holding plate 21 to release the right yarn and pinch the middle and left yarns.

The first embodiment has been described above, and next, the second embodiment will be described with reference to FIG.

In this embodiment, the first thread holding plate 21 and the first and second thread pressing plates 2 in the first embodiment are
4 and 25, protrusions 21a and 24a, 2
5a, etc., and instead, face plate-like elastic bodies 41, 42, 43 are fixedly installed on each of the above-mentioned members by an appropriate processing method. Since this elastic body comes into close contact with the opposing pressing surfaces without any gaps, the yarn clamping effect is good. Further, although illustration is omitted, as another embodiment, instead of installing the protrusion or elastic body, knurling may be performed at the same location, and furthermore, instead of knurling, dot protrusions may be randomly provided. However, the same effects as described above can be expected.

In the above embodiment, the protrusion was provided on the first thread holding plate side, and the second thread holding plate side was provided with a flat surface, but this may be reversed (in this case, the first and second thread (The protrusion of the presser plate should also be oriented in the opposite direction.) The same effect can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a side view of a sewing machine head equipped with a thread switching device of the present invention, Figs. 2 and 3 are a plan view and a front view of Fig. 1, respectively, and Fig. 4 A and B are Fig. 2. FIGS. 5 and 6 are plan views of the grooved cam plate at different positions, and FIGS. 5... Thread tension device, 15... Thread hook, 19... Balance, 1
9a... Threading part, 20... Upper thread, 21, 22... First,
Second thread holding plate, 23a, 23b...long groove, 24,
25...First and second thread presser plates, 21a, 24a, 2
5a...Protrusion, 22a, 24b, 25b...Rising portion, 26...Spacer, 28...Gap, 30...Groove cam plate, 31...Groove, 32...Thread switching lever, 41, 4
2,43...Elastic body.

Claims (1)

[Scope of Claims] 1. In a sewing machine that uses a single thread take-up to sew with a large number of threads, all the threads are hung on the top surface of the thread take-up and moved up and down, and the thread-hanging portion of the thread take-up moves up and down. A first and a second groove having a long groove, bent into an arc shape substantially the same as the locus of the movement, and arranged with an interval in the protruding direction of the balance.
A thread holding plate, a plurality of thread holding plates arranged in parallel between them, having the same long grooves in the vertical direction as described above, and bent in the same manner as the thread holding plate, and the thread holding plates and the thread. a spacer provided between each plate so that a gap is formed at the bottom of the holding plate through which the thread can pass;
a grooved cam plate having a cam groove that engages with the rising portion of the upper part of the plurality of thread presser plates, and by moving the grooved cam plate from side to side, the plurality of thread presser plates can be connected to the first and second thread presser plates. When each thread is lifted by the thread take-up by moving it to the thread holding plate side simultaneously or individually,
Frictional resistance means provided on either one of the first or second yarn holding plates and both of the plurality of yarn holding plates causes the yarns other than the selected yarn to be moved near the top dead center of the thread take-up. A thread switching device for a sewing machine that holds a clamp. 2. The friction resistance means according to claim 1 is provided on either one of the first or second yarn holding plates and on both of the plurality of yarn holding plates, and has an appropriate width, and A thread switching device for a sewing machine comprising a curved protrusion whose contact surface has an equal curvature and a center of curvature when in contact. 3. A sewing machine in which a face plate-like elastic body is fixed to either one of the first or second thread holding plate and a plurality of thread holding plates as the friction resistance means according to claim 1. Thread switching device. 4. A thread switching device for a sewing machine, in which one of the first or second thread holding plates and both of a plurality of thread holding plates are knurled as the frictional resistance means according to claim 1. . 5. A sewing machine in which dot-like projections are randomly provided on either one of the first or second thread holding plate and on both of a plurality of thread holding plates as the frictional resistance means according to claim 1. Thread switching device.