JPH0453583A - Needle thread feeding device in twin needle sewing machine - Google Patents

Abstract

PURPOSE:To prevent the cut of a thread and dispense with complicated works such as rethreading by conducing action by the counting of a determined number of stitch by a counter means after generation of single needle state signal, and alternately conducting drawing control of twin needle state and drawing control of single needle state by the following counting of a determined number of stitch. CONSTITUTION:When the signal of a single needle stopping switch 5 is generated from twin needle sewing state, a single needle stopping electromagnet 6 corresponding to one selected needlebar is energized to form signal needle state. A single needle control circuit 12 holds the electromagnet 3 of a holding means A1 or A2 corresponding to the needle thread on the selected side, and controls to draw only the needle thread on the used side. Two needles after ten stitches work a twin needle control circuit 13 so that it controls an energizing circuit 11 to draw both needle threads T1, T2. After twin needle seams by the two needles are formed, the single control circuit 12 is worked to deliver only the needle thread on the used side. When a signal is generated from a single needle releasing switch after the signal generation of the single needle stopping switch 5, a releasing means works to release the single needle state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention enables one of the needles to be held in a resting state, and - the thread required for forming a seam is drawn from a thread supply source each time a seam is formed. The present invention relates to a needle thread supply device for a two-needle sewing machine.

[Prior art] For example, as described in JP-A-1-204694, stitches are always formed using two needles, and one needle is held in a resting state when forming corner stitches, etc. Sewing machines are known in which the threads of the two needles are pulled out by the required amount for each seam formation. As shown in FIG. 3, the pulling means for pulling out the needle thread consists of a drive roller 1 that constantly rotates in conjunction with a drive source and an idler on the needle thread path between the needle and the thread supply source W. Needle threads T1 and T2 of both needles (not shown) are sandwiched between the roller 2 and the needle threads T1 and T2 can be drawn out from the supply source W,
Before and after, thread gripping means A1, A2, and BIB2 arranged separately for both needle threads T1 and T2 can grip or release each thread, and when released, the threads T1 and T2 can be pulled out. 12, when a predetermined amount of yarn is pulled out, the amount of yarn to be pulled out is set by gripping the yarn gripping means Al and A2 on the supply source W side. These thread gripping means Al, A2, B1. B2 is for holding or releasing the threads T1 and T2 between the electromagnet 3 main body by moving the gripping plate 4 toward and away from the action or non-action of the electromagnet 3.

When the above-mentioned one-needle state is established, that is, when one needle is in a resting state, the electromagnets 3 of the thread gripping means Al and A2 on the supply source W side act so that the needle thread on the resting side is not pulled out. It is designed to be held in a gripped state.

When forming a stitch with two needles using such a sewing machine, if one of the bobbin threads runs out during the two-needle sewing, or if one of the needle threads breaks on the supply source W side, Normally, the bobbin thread is replenished or the threads are connected, but in actual sewing factories, such work is not done, the needle on the side where the bobbin thread has run out or the thread has broken is stopped, and the thread is spliced on one side. After successively forming only one stitch in the needle state (FIG. 4), intermediate stitches were successively formed with the needle on one side in the used state while in the single-needle state.

[Problem to be solved] However, when sewing a stitch on only one side as shown in Fig. 4, the needle thread t of the needle in the dormant state is in the gripping state as described above, so it is not pulled out from the supply source and is sewn according to the sewing. Gradually tension increases, and the seam stretches over a long distance, for example 10
When the distance exceeds the stitch, the tension increases. As a result, the fabric sent to the sewing machine is pulled up by the needle thread t while it is at rest, causing it to roll up, interfering with the sewing process and reducing work efficiency, or causing the worker to touch the rolled up fabric. In the case of thick (heavy) cloth, the tension of the needle thread t between the cloth and the needle may be overcome by the weight, resulting in disadvantages such as the needle thread t connected to the cloth breaking.

Furthermore, at this time, the needle thread is not pulled out by the thread gripping means on the side of the supply source of the needle thread in the rest state and is held in a stationary state, so that the grip plate 4 and the electromagnet A phenomenon in which the needle thread t, which is held between the main body 3 and the main body 3, moves to be pulled out from between the grip plate 4 and the main body 3 because the gripping force on the outside of the grip plate 4 is weak, and eventually falls off. As a result, the needle thread being used and the needle thread t that has fallen from this extraction may become intertwined, interrupting stitch formation, and requiring the troublesome work of rethreading the needle thread t during the next double-needle sewing. occured.

[Means for Solving the Problems] In order to solve these problems, the present invention uses two needles arranged parallel to each other and separated from each other in the direction crossing the cloth feeding direction, and a needle that is electrically operated. Single-needle resting means capable of holding both needles separately in the upper position in a resting state; It has a needle thread gripping means capable of gripping or releasing the thread, and a pulling means that engages with both needle threads on the needle side of the needle thread gripping means and pulls out the needle thread from the thread supply source. During each stitch formation, the double needle thread gripping means releases or grips and releases the needle thread, while the pulling means pulls out a predetermined amount of needle thread, and in the one-sided state where the single needle resting means operates, the needle of the needle thread on the resting side In a sewing machine that holds thread gripping means in a gripping state, there is a switch that, when operated, generates a signal indicating that one needle is in a rest state, a detection means that generates a signal every time the main shaft of the sewing machine rotates, and a signal from the detection means that is counted. a determining means for detecting the counting of a predetermined number of stitches by the counting means; and a discriminating means for detecting the counting of a predetermined number of stitches by the counting means; A control means is provided for alternately controlling the withdrawal of the state and the withdrawal control of the single needle state.

[Function] With this configuration, if the one-needle state continues for a predetermined number of stitches, for example 10 stitches or more, when forming subsequent stitches, the gripping means on the side of the supply source of the needle thread on the idle side is moved every predetermined number of stitches. By controlling the needle thread to be gripped or released at the same time, the needle thread on the resting side does not stay stationary for a long time and prevents excessive tension.

[Example] This example of the present invention will be described with reference to the drawings. Components that are similar to those of the prior art are given the same numbers and descriptions thereof will be omitted.

Reference numeral 5 denotes a one-needle stop switch that turns on the left and right hands separately to generate a signal in connection with the operation of an operating member (not shown) that changes one needle to a rest state so as to change from a double-needle state to a single-needle state;
a pair of single-needle stop electromagnets, which are disposed in a single-needle stop mechanism (not shown) and act on the stop mechanism to selectively hold one of the left and right needle bars (not shown) at top dead center by biasing;
numeral 8 is an energizing circuit that energizes the electromagnet 6 to hold one of the left and right needle bars, and 8 is an ◯R gate that manually outputs both the left and right signals of the single needle stop switch 5.

Reference numeral 9 denotes a one-needle release switch that is turned on to generate a signal when the rest state is released in connection with the operation of a release operation member (not shown) arranged in relation to the above-mentioned rest mechanism, and reference numeral 10 denotes a one-handle release switch 9 at a predetermined time. This is a switch discrimination circuit that discriminates the output state of the switch.

Reference numeral 11 indicates a biasing circuit for separately biasing both types of magnets 3 of the gripping means Al and A2 on the front side (on the thread supply source W side) of the roller 1.2 of the thread pulling means, and reference numeral 12 is used when the needle is in a single-needle state. Gripping means AI corresponding to the needle thread TIT2 of one of the left and right needles in the state
, a one-sided needle control circuit that controls the energizing circuit 11 to energize the electromagnet 3 of A2; 13 is a double-needle gripping means A;
This is a two-point control circuit that controls the energizing circuit 11 to energize the electromagnet 3 of 1 and A2. Reference numeral 14 denotes a yarn amount control means which instructs the amount of yarn to be pulled out for each stitch and controls the electromagnet 3 so that the amount of yarn pulled out is the set amount.

14 is rotation detection means that generates one pulse in relation to one revolution of the sewing machine main shaft (not shown); 15.16
is a 1-th point that counts the signal of the rotation detection means 14 at a predetermined time.
and a second counter circuit; 17 is a determination circuit for determining whether the count value N of the first counter circuit is 10 or more; 18;
is a determination circuit that determines whether the count value E of the second counter circuit 16 is smaller than 2 or has reached 10.

The structure of the present invention is as described above, and the operation will be explained next with reference to the flowchart of FIG. 2.

When a signal from the single-needle stop switch 5 is generated from the double-needle sewing state, the single-needle stop electromagnet 6 corresponding to the selected one needle bar is energized, resulting in the single-needle sewing state (step 2). This signal also clears the count value N of the first counter circuit 15 (step 2). The state of the one-needle release switch 9 is determined by the switch determination circuit 10 (step ■)
. When it is off, the first counter circuit 15 is enabled and the first counter circuit 15 counts the signal from the rotation detection means 14 (step (2)), the one-sided needle control circuit 12 is activated (step (2)), and the control circuit 12 is stopped. The electromagnet 3 of the gripping means A1 or A2 corresponding to the needle thread on the selected side is held in an energized state, and control is performed so that only the needle thread on the use side is pulled out. The count discrimination circuit 17 determines the count value N〉
When determining 10 (step ■), that is, single needle stitch is 10
When the count value E of the second counter circuit 16 is cleared (step (2)), the switch discrimination circuit 10 discriminates the state again (step (2)). When it is off, the second count circuit 16 is enabled and the second count circuit 16 counts the signal of the rotation detection circuit 14 (Step ■), and the count discrimination circuit 18 discriminates if the count value E>2 (Step [Phase] ). Until it is determined that E>2, that is, for the two needles after the middle needle, the double needle control circuit 13 is activated to control the double needle threads T1 and T2.
Step ■) to control the energizing circuit 11 so as to draw out the
When it is determined that E>2, that is, after the two-needle stitch is formed, the one-sided needle control circuit 12 is activated again to perform needle thread delivery on only the use side as described above (step @). When the discrimination circuit 18 discriminates E=10 (step ■),
That is, after performing single-needle sewing with a claw needle, the second counter circuit 16
Clear and repeat steps ■-■. When a signal is generated from the single-needle release switch after the single-needle stop switch 5 generates a signal, the release means is activated to release the single-needle state (step 0).

In this embodiment, during the first intermediate needle, the one-side needle control circuit 12 controls the one-side needle control circuit 12 to prevent the needle thread from being fed out. This setting was made because the corner stitch is usually within the length of a bochu needle.

Further, the count discrimination value of the count discrimination circuit 1718 in this embodiment is configured to be arbitrarily set.

Further, it may be configured by computer control or by a hardware circuit so as to perform the same function as in the block diagram of this embodiment.

[Effects] With this invention, when single-needle sewing continues for a predetermined number of stitches or more, thread withdrawal in a single-needle state and thread withdrawal in a double-needle state for a predetermined number of stitches are then alternately repeated. Even if the needle thread connected to the cloth in a resting state is pulled by the movement of the cloth, it will not be cut due to tension or the like, and the cloth will not be rolled up and interfere with the sewing work. Furthermore, when the thread gripping means on the thread supply source side has a structure as shown in Fig. 5.6, the needle thread between the gripping plate and the electromagnet body cannot be pulled out, and the thread cannot be rethreaded. The effect of eliminating the need for complicated work can also be obtained.

Figure 2

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the control circuit of this embodiment, Fig. 2 is a flowchart of this embodiment, Fig. 3 is a schematic front view of a conventional thread pulling means, and Fig. 4 is a single-needle sewing during double-needle sewing. FIG. 5 is an explanatory diagram showing the state of the thread gripping means A and the needle thread t. FIG. FIG. Applicant name Juki Co., Ltd. Figure 4

Claims (2)

[Claims] (1) Two needles arranged parallel to each other and separated from each other in the direction intersecting the cloth feeding direction, and a one-needle resting means that can individually hold both needles in a resting state at an upper position by electrical action; Needle thread gripping means electrically actuated or inactive to grip or release the needle thread separately on both needle thread paths between the needle thread supply source and the needle; and a pull-out means that engages with the thread of both needles on the side and pulls out the needle thread from the thread supply source, and in the double-needle state, the thread gripping means for both needles releases or grips and releases the needle thread each time each stitch is formed. In a sewing machine, a pulling means pulls out a predetermined amount of needle thread, and in a one-needle state in which a one-needle resting means operates, a needle thread gripping means for the resting needle thread is held in a gripping state, whereby one needle is brought into a resting state by an operation. a switch (5) that generates a signal indicating the
), counting means (15, 16) for counting the signals of the detection means, and determining means (1) for detecting the counting of a predetermined number of stitches by the counting means.
7, 18), it acts by counting a predetermined number of stitches by the counting means after the signal for the single needle state is generated, and then by counting the predetermined number of stitches, the withdrawal control for the double needle state and the withdrawal control for the single needle state are alternately performed. A needle thread supply device for a two-needle sewing machine, comprising: control means (12, 13) for controlling the needle thread supplying device. (2) The needle thread supply device for a two-needle sewing machine according to claim 1, wherein the predetermined number of stitches determined by the determining means is a different number of stitches.