JPH0153386B2 - - Google Patents

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention involves hanging a plurality of sewing threads on one thread take-up, and attaching the non-sewing thread to the movement of the thread take-up near the top dead center of the thread take-up. This invention relates to a mechanism for pulling up a needle thread that is held stationary regardless of the need for use, and is used in a needle thread switching device of a sewing machine.

(Prior Art) Conventionally, as this type of device, the following technology shown in FIG. 5 has been obtained. (Japanese Unexamined Patent Publication No. 59-47466) That is, in the figure, 31 is the take-up bin, 31a is the tip of the take-up bin formed in the fork, 32 is the thread guide stand, and 3
Numerals 3 and 34 are thread guides, and 35 is a thread guide, in which the tip end 31a of the thread take-up enters into each long groove, allowing the thread take-up to move up and down. 40 is a switching cam and thread guide middle 3
The upper ends of 3 and 34 are moved to release and regulate the thread paths 37, 38, and 39. When switching the sewing thread, set the thread take-up near the top dead center (stop position after thread trimming operation), operate the switching cam 40, and release any of the thread paths 37, 38, and 39 through which the desired thread passes. do. In the remaining thread paths, the thread is held between a thread guide stand 32, thread guides 33 and 34, and a thread guide 35.

(Problems to be Solved by the Invention) In the above technique, since the non-sewing thread is clamped near the top dead center of the take-up, the thread is held slightly below the top dead center of the take-up. becomes. Therefore, there was a risk that the thread would come into contact with the thread take-up at the top dead center of the thread take-up, causing the holding thread to break. The present invention is intended to prevent such inconveniences from occurring.

[Structure of the invention]

(Means for solving the problems) In order to solve the above problems, the present invention takes the following measures. That is, as shown in FIGS. 2 to 4, the drive arm 4 is fixed to a push-down shaft 8 supported on the machine frame.
Then, the rod arm 21 was fixed to the thread pulling arm shaft 14 which was rotatably supported on the thread pulling arm stand 2. The thread pulling drive arm 4 and the rod arm 21 are connected by a rod 3, and there is a spring 5 which is a biasing means for biasing the rod 3 in one direction, and a stepped shaft 7 that supports this.
is provided on the thread pulling drive arm 4. Said rod 3
There is a long hole 3 which is a means of connection with the thread pulling drive arm 4.
a is provided and connected with a step screw 6, but the elongated hole 3
A allows the thread pulling drive arm 4 to further swing even if the movement of the rod 3 is restricted. 1 is a thread pulling arm fixed to the thread pulling arm shaft 14.
The thread pulling arm stand 2 is provided with a stopper 22 for regulating the swinging of the thread pulling arm 1.

(Function) When the thread pulling drive arm 4 is driven, the thread pulling arm 1 swings. Then take the thread up to the top dead center 2
3. Pull it up and hold it. Therefore, the non-sewing thread is held without contacting the thread take-up.

(Example) In FIG. 1, a needle bar guide shaft 23 is fixed to an arm and guides the vertical movement of a needle bar crank rod end 24, which is connected to a crank rod that moves up and down due to the rotation of an upper shaft (not shown). has been done. The needle bar crank rod end 24 has a convex portion 24a, which engages with concave portions 25b, 25b' of the needle bar and moves up and down the needle bar. The plurality of needle bars 25, 25' are supported by a needle bar arm 26. The non-sewing needle bar includes a push-down bar 18 fixed to the push-down arm 16, a convex portion 17b of the push-down body 17, and recesses 25a, 25 at the upper end of the needle bar.
It is held in the standby position by engagement of a'.

The sewing needle bar is attached to the protrusion 2 on the needle bar crank rod end.
4a and the concave portions 25b, 25b' of the needle bar and the relief 17a of the convex portion of the push-down body 17, the needle bar can be moved up and down independently of the non-sewing needle bar, and becomes ready for sewing.
As shown in FIGS. 2 to 4, the push-down arm 16 that fixes the push-down rod 18 and the push-down body 17 is fixed to a push-down shaft 8, and the push-down shaft 8 is swingably supported by the arm. 20 is a solenoid connected to the push-down arm 16, and the swing motion of the push-down arm is transmitted by the solenoid. A thread pulling arm 4 is fixed to the other end of the push-down shaft 8, and a thread pulling arm 1 fixed to a thread pulling arm shaft 14 with a screw 15 is rotatably supported on a thread pulling arm stand 2 fixed to the arm. ing. A rod arm 21 is fixed to the other end of the thread pulling arm shaft 14. A stopper 27 for the thread pulling arm 1 is fixed to the thread pulling arm stand 2 to restrict the swinging of the thread pulling arm 1. A rod 3 connecting the rod arm 21 and the thread pulling drive arm 4 is supported by a step screw 6. A spring 5 is held on the thread pulling drive arm 4 by a step screw 7 so as to press the rod 3 to the right, and is locked by the thread pulling drive arm 4 and the rod elongated hole 3b. The rod 3 has a long hole 3a so that only the thread pulling drive arm 4 can swing even if the movement of the rod is restricted.
have.

In the take-up section, a thread path is formed by a thread guide stand 11, a thread guide middle 10, a thread guide guide 9, and a spacer 12. ing. Pins 10a and 9a are attached to the thread guide 10 and the thread guide 9 above the top dead center of the thread take-up, and the pin 10a of the thread guide 10 is connected to a hole (not shown) in the thread guide stand 11. The thread guide pin 9a enters a hole (not shown) in the thread guide and holds the non-sewing thread. This switching of the holding is performed by moving the upper end of the thread guide 10 (not shown).

The operation of the present invention will be described below.

The range in which the upper thread can be switched is the upper stop position after thread trimming (50° to 70° when the top dead center of the needle bar is 0° in the embodiment). In the case of 50° to 70°, the height of the needle bar at the sewing position will stop at a lower position at 70° than at 50°. When switching the upper thread, push the non-sewing needle bar up to the height where the sewing needle bar is stopped, make the recesses of multiple needle bars the same height, and then move the needle bar arm to switch the sewing needle bar. At the same time, this is done by switching the thread path and switching the thread holding.

To explain the case of 50 degrees in FIG. 3, the push-down arm 16 swings due to the operation of the solenoid 20, and the non-sewing needle bar is pushed down by the convex portion 17b of the push-down body 17. Then, the sewing needle bar swings until the upper end of the stationary sewing needle bar comes into contact with the push-down bar 18.

In addition, the thread pulling drive arm 4 swings together with the swing of the push-down arm 16, and the thread pull-up drive arm 4 swings to the rod arm 21 via the rod 3.
is swung, and the thread pulling arm 1 is pulled up above the pin 9a of the thread guide 9, which is located above the top dead center of the bobbin. At this time, the thread pulling arm 1 is in contact with the stopper 27, or is on the verge of contact.

To explain the case of 70 degrees in FIG. 4, the thread pulling arm 1 swings until it comes into contact with the stopper 27 and does not swing any further, but the push-down arm 16 swings further. At this time, the movement of the rod 3 is regulated by the thread pulling arm 1 and the stopper 27, but the thread pulling driving arm 4 resists the spring 5 and pulls into the elongated hole 3a of the rod.
As a result, the push-down bar 18 swings until it comes into contact with the upper end of the stationary sewing needle bar. In the case of 50° and 70°, after this, move the thread guide intermediate 10 to the thread guide stand 11 or the thread guide 9 side, and press each pin 9a, 10a.
The thread is held and released by engaging or disengaging the hole.

〔Effect of the invention〕

In order to compensate for the drawbacks of the prior art, a mechanism is also conceivable in which the thread pulling arm and the thread pulling driving arm are interlocked and the swinging motion of the thread pulling arm is changed depending on the magnitude of the swinging of the thread pulling driving arm. However, with this type, the amount of thread being pulled up varies, and when the amount of thread being pulled up is large, there is a problem that the thread may fall out of the needle hole. In the present invention, the connecting means between the rod and the thread pulling drive arm is made into an elongated hole, and the rod is pushed in one direction by the biasing means, so even if the thread pulling arm hits the stopper and the movement of the rod is restricted, Only the thread pulling drive arm moves independently. Therefore, regardless of the magnitude of the oscillation of the thread pulling drive arm, the oscillation of thread pulling is constant, regardless of the needle, thread type, count, and the length of thread remaining from the needle hole after thread trimming. There is an effect that the thread can be pulled up above the thread take-up dead center without changing the thread take-up, and the problem of the thread coming out from the needle hole does not occur. Further, since the overturn mechanism is disposed on the thread pulling drive arm side, there is an effect that the thread can be threaded easily without getting in the way when threading. In addition, the biasing means is not relevant until the thread pulling arm and the stopper come into contact, and only the swinging of the thread pulling drive arm after the contact acts, and the solenoid starts to act as a spring after the suction force becomes strong. Therefore, it can be operated with a small solenoid. Also,
Another advantage is that the solenoid can be built into the sewing machine arm.

[Brief explanation of drawings]

FIG. 1 is an explanatory view of the state of the needle bar related to the needle thread pulling mechanism of the present invention, and FIGS. 2 to 4 are explanatory views of the configuration and operation of the present invention. Figures 3 and 4 are illustrations of the thread pulling-up operation (50°) and (70°) respectively], and Figure 5 is an explanatory view of the prior art. 1... Thread pulling arm, 2... Thread pulling arm stand, 3...
...Rod, 3a...Elongated hole (connecting means), 4...Thread pulling drive arm, 5...Spring (biasing means),
9... Thread path guide, 10... Thread path guide, 11... Thread guide stand, 16... Push down arm, 20... Solenoid,
21...rod arm, 27...stopper.

Claims (1)

[Claims] 1. When switching the needle thread, the non-sewing needle bar is lowered to the height of the needle bar at the sewing position, and at the same time as the needle bar is switched, the thread on the non-sewing side is held, regardless of the movement of the thread take-up. A needle thread switching device that stands still and stands by includes: a push-down shaft fixed to a push-down arm that pushes down the non-sewing needle bar and pushes it up to a standby position, a thread pull-up drive arm fixed to the push-down shaft, and a thread fixed to the machine frame. a thread-pulling arm stand, a thread-pulling arm fixed to a thread-pulling arm shaft which is rotatably supported on the thread-pulling arm rest, one end of which is rotatably supported by a rod fixed to the thread-pulling arm shaft, and the other end of which is rotatably supported by the thread-pulling arm shaft; a rod rotatably supported on the lifting drive arm via a connecting means;
One end is locked to the thread pulling drive arm, and the other end is locked to the rod, thereby urging the thread pulling drive arm in one direction with respect to the rod, and even after the movement of the rod is restricted. An upper thread pulling device for a sewing machine, comprising: biasing means that can be slid independently via a connecting means.