JPH0663265A - Automatic control device for amount of thread drawing-out for sewing machine - Google Patents

Abstract

PURPOSE:To provide an automatic control device for a sewing machine whereby a proper amount of thread drawing-out can be set even if stitch types such as a straight stitch and a close stitch are different. CONSTITUTION:A thread is drawn out according to the amount of thread drawing-out operated on the basis of sewing-data and sewing is done. A detecting means 11 for detecting the directional change of the sewing and a detecting means 12 for detecting the amount of movement along the direction of the sewing are provided. Whether a straight stitch or a close stitch is determined due to both the directional change of the sewing and the amount of the movement before and after the directional change, and according to its determination, the amount of the thread drawing-out is controlled. In concrete terms, when sewing direction is changed and the sum of the amount of the movement along the sewing direction at that time and the amount of its directional movement at the next time is larger than a fixed value, a stitch type is determined as the close stitch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic thread feed-out amount adjusting device for a sewing machine, and more particularly, an automatic thread feed-out amount adjusting device for a sewing machine which feeds a thread according to a thread feed-out amount calculated according to sewing data. Regarding

[0002]

2. Description of the Related Art Conventionally, a sewing machine controls an on / off time of a first solenoid and a second solenoid according to sewing data to control an appropriate amount of thread delivery. That is, as shown in FIG. 4, the yarn 7 unwound from the thread spool 1 is guided by the first solenoid 3, the auxiliary balance 4, and the second solenoid 5 while being tensioned by the base tension 2. When the yarn is delivered, the first solenoid 3 is turned off and the second solenoid 5 is turned on, and the auxiliary balance 4 moves horizontally in FIG. 4, whereby the yarn 7 is delivered from the thread spool 1 by a predetermined amount. . This yarn feeding amount is obtained by setting X as the yarn swing amount, Y as the cloth feed amount, D as the cloth thickness, and K1 and K2 as parameters.

[0003]

[Equation 1]

Is calculated in accordance with After the calculated thread feeding amount is detected by the encoder 8, the first solenoid is turned on and the second solenoid is turned off, and the sewing is performed with the yarn feeding amount measured according to the hand movement.

In such a sewing machine, if D is measured by a cloth thickness sensor and K1 and K2 are set in advance for each type of pattern, an appropriate amount of thread to be extended is calculated for each pattern,
Sewing is automatically performed with a predetermined thread feeding amount.

[0006]

In a sewing machine which performs sewing by calculating the amount of thread to be fed out as described above, an appropriate amount of thread to be fed out is given to one pattern by the above calculation formula, but a large pattern or the like is used. In a pattern in which straight stitching and close stitching (meaning fine pitch of zigzag pattern) are mixed,
There is a drawback in that it is not possible to calculate a fine thread feeding amount for each stitch due to the different sewing types.

Therefore, the present invention has been made in order to solve such a drawback, and an automatic thread feed-out amount of a sewing machine capable of setting an appropriate thread feed-out amount even when sewing types such as straight stitching and close stitching are different. It is an object to provide an adjusting device.

[0008]

In order to solve this problem, the present invention provides an automatic thread feed-out amount adjusting device for a sewing machine, which feeds a thread according to a thread feed-out amount calculated in accordance with sewing data and performs sewing. A direction detecting means for detecting the change of the sewing direction, a moving amount detecting means for obtaining the moving amount along the sewing direction, and a means for determining whether the sewing is a straight stitch or a close stitch based on the change in the sewing direction and the moving amount before and after the sewing direction. Adopted a structure that adjusts the thread feeding amount according to whether it is straight stitching or close stitching.

[0009]

With such a construction, the switching of the sewing direction and the amount of movement before and after the sewing direction are obtained in accordance with the sewing data, and the straight line stitching and the close stitching are discriminated accordingly. Therefore, the straight-line stitching and the close-fitting stitching are individually calculated, and the thread let-out amount is calculated for each stitch. In this way, even when the sewing style is different for one sewing pattern, the thread let-out amount is automatically adjusted and optimum sewing can be performed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 shows a configuration for calculating the thread let-out amount by discriminating between straight line stitching and close stitching. In the figure, reference numeral 10 indicates a data generator for generating sewing data. The sewing data from this sewing data generator 10 is
It is input to the direction detector 11 and the movement amount detector 12. The direction detector 11 detects the switching of the sewing direction by detecting the difference in the sign of the movement amount in the sewing direction for each sewing in the predetermined sewing direction. The movement amount detector 12 detects the movement amount for each sewing in the sewing direction. A comparator 15 is connected after the movement amount detector 12, and this comparator 15 compares the sum Lx, y of movement amounts in the sewing direction before and after a certain stitch with a predetermined threshold value Lk. The comparison result is input to the AND gate 16. The AND gate 16 is made conductive when the change in the sewing direction is detected by the direction detector 11, and when the sum Lx, y of the front and rear movement amounts at that time is larger than a predetermined threshold value Lk, the thread connected thereafter. The yarn feeding amount calculator 17 sets the yarn feeding amount.

Next, a method for discriminating close stitches in such a structure will be described with reference to FIGS. 2 and 3.

Now, as shown in FIG. 2A, M0 (x
0, y0), M1 (x1, y1), ... Mn are sewn in this order. At this time, M0 to M1 and Mn-2 to Mn are thread stitches for straight stitching, and M1 to M5 are thread stitches for tight stitching. Suppose.
Since the sewing data is relative data, the sewing direction can be detected by detecting whether the data at the next needle drop point is positive or negative. For example, when examining the signs of the amounts of movement of the needle entry points of M0 to Mn in the x and y directions, it is always + in the x direction for each needle entry point, and y
It is understood that the sign of the moving amount is switched at the needle drop points of M2 to M5 in the direction.

Therefore, as shown in step S1 of FIG. 3, the direction detector 11 determines the difference between the signs of the current y-direction movement amount and the next y-direction movement amount. If the signs match, move to step S2 and perform the same operation x
Determine the direction.

On the other hand, when it is detected in step S1 that the code has been switched, in step S3, the sum of the amounts of movement in the front and rear sewing directions when switching is performed by the movement amount detector 12, that is, this time (switching). Then, the sum Lx of the movement amount in the x direction and the next movement amount in the x direction is calculated. Next, in step S4, the comparison between Lx and Lk is performed using the comparator 15. The threshold value of Lk is an empirical value obtained experimentally.

If it is determined in step S4 that Lx is smaller than (or equal to) Lk, it is determined in step S5 that the stitching is a close stitch, and the thread let-out amount is set by an arithmetic expression of the thread let-out amount corresponding to it. The yarn feeding amount is set, for example, by setting K1 and K2 to the corresponding values in the arithmetic expression (1). On the other hand, in step S4, L
If it is determined that x is not smaller than Lk, step S
Up to 2.

The steps S2, S6 and S7 are
This time, the sign Ly is changed in the x direction and the sum Ly of the movement amounts in the y direction before and after that time is obtained. If Ly is smaller than (or equal to) Lk, step S
In step 5, it is determined to be close stitching, and if not, it is determined to be straight stitching in step S8 and the thread feeding amount is set. The thread feeding amount in the straight line sewing is set by using the arithmetic expression (1) as in the close contact sewing, but the parameters of K1 and K2 at this time are set to values corresponding to the straight line sewing.

FIG. 2B shows various examples of objects to be judged in steps S4 and S7. Now P1 to P0
Each example will be described in the case where the needle drop point advances to, and then the needle drop point changes to P2, P3, P4 or P5.

When the P1-P0-P2 seam is formed, the signs alternate in the y direction, so the amount of movement in the x direction is calculated (step S3). Since the sign is switched at P0, the current movement amount is the movement amount of P1-P0 in the x direction,
The next movement amount is the movement amount of P0-P2 in the x direction.
As shown in FIG. 2C, each moving amount is Δx1, Δ
Since it is x2, the sum of the movement amounts is L1 (= Lx) = Δx1 + Δ
x2. Therefore, when L1 is smaller than (or equal to) Lk, it is determined that the stitching is close contact.

Next, in the case of P1-P0-P3, L2 is L1
This is the case when it is not judged to be a close stitch because it is considerably larger. Further, in the case of the P1-P0-P4 stitch, the signs alternate in the x direction, so the sum of the movement amounts in the present and next y directions is calculated (step S6). Sum of this movement L4
Is also relatively large, and is not judged as close stitching. Further, when the sign changes in the x and y directions as in the case of P1-P0-P5, it is determined that the close stitching is performed only when both L5 and L6 are smaller (or equal) to Lk.

In the embodiment described above, the threshold value is one kind, but a plurality of threshold values may be provided and the yarn feeding amount corresponding to each threshold value may be set.

Further, in the above-described embodiment, when the sewing direction is switched and the sum of the movement amount along the sewing direction at that time and the next movement amount in that direction is larger than the predetermined value, it is determined that the stitching is a close stitch. However, it may be determined that the close stitching is not started until this condition is repeated several times.

Further, although the calculation formulas for the straight line stitching and the close stitching are obtained by changing the parameters of (1) respectively, separate and unique calculation formulas may be used.

[0024]

As described above, according to the present invention,
A means for distinguishing between straight line stitching and close stitching is provided based on the change in the sewing direction and the amount of movement before and after it, and the thread let-out amount is adjusted according to whether the stitch is a straight stitch or a close stitch. Even when the sewing types are different, the thread let-out amount is automatically adjusted to enable optimum sewing.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a device of the present invention.

2A, 2B, and 2C are diagrams for explaining calculation of a movement amount in a sewing direction.

FIG. 3 is a flow chart for explaining the operation of the present invention.

FIG. 4 is a configuration diagram illustrating a mechanism for adjusting a yarn feeding amount.

[Explanation of symbols]

 10 Sewing data generator 11 Direction detector 12 Movement amount detector 15 Comparator 17 Thread feeding amount calculator

Claims (2)

[Claims] 1. An automatic thread feed-out amount adjusting device for a sewing machine, which feeds a thread according to a thread feed-out amount calculated according to sewing data to perform sewing, and direction detecting means for detecting a change in sewing direction, and movement along the sewing direction. A feature is that a moving amount detecting means for obtaining the amount and a means for discriminating between linear stitching and close stitching based on the change in the sewing direction and the moving amount before and after the sewing direction are provided, and the thread let-out amount is adjusted according to the straight stitch or close stitching. An automatic thread feeding amount adjusting device for sewing machines. 2. When the sewing direction is changed and the sum of the movement amount along the sewing direction at that time and the next movement amount in that direction is smaller than or equal to a predetermined value, it is determined to be close stitching. The automatic yarn pay-out amount adjusting device for a sewing machine according to claim 1.