JP2849185B2 - 2-needle sewing machine with upper thread supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-needle sewing machine with a needle thread supply device for beautifully sewing a corner curve or the like.

[Conventional technology]

Turn the upper left thread amount setting volume or upper right thread amount setting volume to change the open time of the solenoid of the left thread presser or right thread presser to change the upper thread supply amount of the left needle or right needle. Needle sewing machines are widely known.

[Problems to be solved by the invention]

In a conventional two-needle sewing machine with a needle thread supply device, the needle thread supply amount of the left and right needles can be changed in advance, but only in a limited range during sewing, such as in the case of sewing a corner curve or the like. It was difficult to change the upper thread supply of one of the needles under specific conditions.

In the sewing of a corner curve, although the set feed pitch of the inner and outer needles is constant, the actual amount of movement (hand movement) of the cloth by the inner and outer needles is Is smaller than a straight line.
However, since the supply amounts of the upper thread of the left and right needles do not change, the upper thread of the inner needle has a surplus state, resulting in a seam with poor tightening.

An object of the present invention is to provide a two-needle sewing machine with a needle thread supply device that can sew a corner curve or the like with a beautiful stitch.

B. Configuration of the Invention [Means for Solving the Problems] In order to achieve the above object, a two-needle sewing machine according to the present invention includes a roller that constantly rotates and feeds left and right threads, and a left and right An upper thread supply device including a left thread presser and a right thread presser that individually pass through and open at predetermined time intervals, and a thread presser that intermittently opens and closes the left and right threads sent from the rollers for each stitch. During sewing, without changing the feed pitch of each needle, the opening time of the left thread presser or right thread presser is changed at a rate stored in advance to supply the upper thread of either one of the needles. It is provided with a means for temporarily changing the amount.

[Action]

In the two-needle sewing machine with the needle thread supply device configured as described above, the needle thread supply amount of one of the needles is temporarily reduced during the sewing operation, even though the feed pitch of the left and right needles does not change. The curve and the like are sewn without the upper thread of the stitches of both needles sagging.

〔Example〕

First, an outline of an upper thread supply device of a two-needle sewing machine with an upper thread supply device will be described with reference to FIG.

This device includes a thread guide 3, a left thread presser 4, a right thread presser 5, a driving roller 6, a driven roller 7, and a thread presser 8.

The yarn guide 3 guides each yarn drawn from the left yarn bobbin 1 and the right yarn bobbin 2.

The left thread presser 4 and the right thread presser 5 are each formed of a solenoid that individually passes through each thread drawn from the thread guide 3 and presses it.

The driving roller 6 and the driven roller 7
Is rotated by the power from the left and right to send the left and right yarns.

The drive roller 6 is provided with an encoder (not shown) having a plurality of slits for sending pulse signals for instructing the opening times of the left thread presser 4 and the right thread presser 5. The left thread presser 4 and the right thread presser 5 repeat opening and closing at predetermined time intervals according to the signal.

The thread presser 8 is made of a solenoid that passes right and left threads sent from the driving roller 6 and the driven roller 7 to the slack, and intermittently opens and closes every one stitch.

Further, the upper thread supply device is provided with an upper left thread amount setting volume 9 and an upper right thread amount setting volume 10 for changing the opening time of the left thread presser 4 and the right thread presser 5.

Instructions are sent separately from these volumes 9 and 10 to the central processing unit, and the signals sent from the encoders are arithmetically processed to change the opening times of the left thread presser 4 and the right thread presser 5 to change the respective upper thread presses. The supply amount is determined.

Reference numerals 11 and 12 denote manual left and right thread amount change switches for instructing by a system different from the upper left thread amount setting volume 9 and the upper right thread amount setting volume 10 and adding a feed amount of a previously programmed amount. Details will be described later.

Next, the second needle sewing machine with a needle thread supply device
An example of performing curve stitching as shown in the figure will be described.

For example, when performing a curve stitch with a curvature radius of 8 mm for the inner hand at the corner of the cloth (interval of the left and right needles is 1/4 in), the upper thread supply amounts of the left and right needles are equal from the front to the position A, but from the position A At the curve sewing point extending to the position B, a beautiful stitch cannot be obtained unless the inner needle is supplied with a needle thread supply amount that is about half that of the outer needle. Therefore, the third
The upper thread supply amount corresponding to the hand movement as shown in the figure is stored in the storage device in advance. That is, for each stitch of the needle at the curve sewing position, a percentage of the upper thread supply amount at the time of straight stitching to determine the upper thread supply amount is determined and stored.

FIG. 4 is a block circuit diagram embodying the present invention.

In this figure, the curve stitching correction data is stored in the storage device 14.

Describing based on this figure, the counter 16 counts a signal for each stitch from the spindle phase detecting device 15, that is, the number of stitches. Further, a signal is sent from the spindle phase detecting device 15 to the feed-out timing control device 18 and the read-out timing control device 19.
The timing control of the upper thread payout 22 (which means the upper thread supply device described in FIG. 1) and the control of the readout controller 20 are performed.

When one of the left and right thread amount change switches 11 and 12 is manually pressed immediately before the curve sewing is started, the counter 16 is set to the initial value 0 and the counting of the number of stitches is started. Then, the signal is sent to the count determination device 17. When the initial value signal from the count determining device 17 is sent to the read control device 20, the read timing control device 19
Is sent to the storage device 14, and the storage device 14 reads out the stored curve sewing data (correction table) and sends it to the central processing unit 13. The central processing unit 13 performs one of the curve stitches based on the curve stitching data and the input signals from the upper and lower thread setting volumes 9 and 10 and the feed pitch detector 21 (the pitch of the curve stitches is invariable). The needle thread feed amount for each needle is calculated and sent to the feeding device 22. When the number of stitches reaches a predetermined value, the count discriminating device 17 and the reading control device
A command is issued from 20 and the curve sewing is completed. In addition,
After pressing one of the left and right thread amount change switches 11 and 12, the operator may assist by holding the vicinity of the center of the curve sewing by hand.

When a curve stitch is performed with a two-needle sewing machine with a needle thread supply device having such a program, the needle operation inside the curve becomes small, and the needle thread supply amount decreases accordingly. Seam that was
You can make beautiful seams with tight threads.

In addition, since the upper thread supply amount of the inner needle for curve stitching is corrected based on the upper thread feed-out amount of the straight section, regardless of the type of thread or cloth, the correction takes into account only the needle movement, It is possible to obtain a sufficiently beautiful corner seam.

Furthermore, even if the time for turning on the thread amount change switch 11 or 12 and the time when the needle moves to the curve of the cloth slightly deviate, it takes two or three stitches for the correction amount to be maximum as shown in FIG. The effect on the seam is small. In particular, in the case of the needle feed sewing machine, since the tightening of the seam goes back to the seam two to three stitches earlier, a uniform seam is formed.

The above operation is represented in a flowchart as shown in FIG. Although the example in which the correction of the upper thread supply amount is reduced with respect to the upper thread supply amount of the straight stitch portion has been described, switching to the increase also has an effect in responding to a sudden step portion and the like.

C. Effects of the Invention Since the present invention is configured as described above, it has the following effects.

That is, even if a portion such as a corner stitch is in the middle of the sewing stage, a beautiful two-line stitch with a tight thread can be formed by a simple operation regardless of the type of thread or cloth.

[Brief description of the drawings]

FIG. 1 is a perspective view of a two-needle sewing machine with a needle thread supply device, and FIG.
FIG. 3 is a view for explaining a stitch of a corner curve, FIG. 3 is a view showing a ratio of a supply amount of an upper thread for each stitch at the time of curve stitching with respect to a supply amount of an upper thread in a straight stitch portion, and FIG. A block circuit diagram of a two-needle sewing machine with a thread supply device,
FIG. 5 is a diagram of curve stitching. 4 ... left thread presser 5 ... right thread presser 6 ... drive roller 7 ... driven roller 8 ... thread presser 9 ... upper left thread amount setting volume 10 ... upper right thread amount setting volume 11
… Left thread amount change switch, 12 right thread amount change switch,
13 ... Central processing unit, 14 ... Storage device, 16 ... Counter

Claims (1)

(57) [Claims] A roller that constantly rotates and feeds left and right yarns;
A left thread presser and a right thread presser, which are arranged in front of the roller and pass right and left threads individually and open and close at predetermined intervals, and intermittently open and close every thread by passing the left and right threads sent from the roller. An upper thread supply device including a thread presser is provided, and during sewing, the opening time of the left thread presser or the right thread presser is changed at a rate stored in advance without changing the feed pitch of each needle. A two-needle sewing machine provided with a means for temporarily changing the upper thread supply amount of one of the needles.