JPH0246848Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a buttonhole sewing method that controls the pitch of the crossing stitches required to sew the overlock stitches on both sides of automatic buttonhole sewing from the same direction depending on the fabric thickness. This invention relates to a feed pitch control device.

Prior Art Recently, in order to align the zigzag overlock stitches on both sides of a buttonhole, sewing on both sides is always performed from one direction. For this reason, the fifth
As shown in figure a, after performing zigzag stitch 1 on the left side in the direction of the arrow, perform bar stitch 2 and move to the right side, then perform cross stitch 3 and move to the right side of the initial position, and then perform bar stitch After performing step 4, zigzag stitch 5 on the right side is sewn in the same direction as the zigzag stitch 1 on the left side. In addition, in FIG. 5b, after performing a crossing stitch 6, performing a zigzag stitch 1 on the left side and returning to the original position, then performing a crossing stitch 3, performing a barter stitch 2 and moving to the right side, Zigzag stitch on the right side 5
After performing this step, bar stitch 4 is performed and the process is completed. Furthermore, as shown in FIG. 5c, left and right zigzag stitches 1 and 5 are sewn in the same direction in reverse.

Problems to be Solved by the Invention However, in this conventional automatic buttonhole sewing device, the pitch of the zigzag stitch can be changed, but the pitch of the crossing stitch cannot be changed. Therefore, if the stitching pitch is set to be large, the shape of the buttonhole will be defective as described below. First, as shown in Fig. 5d, when the left side crossing stitch 6 is performed and the specified length is reached, the reversing switch is turned on and the left side zigzag stitch 1 is performed with the feed reversed. Assume that the reversing switch is turned on at the end of the first stitch just before the end of the stitching section of the left cross stitch 6 to perform the left zigzag stitch 1. Next, perform the crossing stitch 3 on the right side,
When the reversing switch is turned on, bar tacking 2 is carried out. At this time, if the reversing switch 13 is turned on at the beginning of the last stitch in the feed section of the right side crossing stitch 3, the crossing stitch 6 will have the same stitch. There was a problem that the number of needles was reduced and there was a gap.

Conversely, when the reversing switch is turned on at the beginning of the last stitch in the feed section of the left side crossing stitch 6, the left side zigzag stitch 1 is performed after this last stitch is finished. Next, if you perform right side crossing stitch 3 and the reverse switch is turned on at the end of the stitch one stitch before the end of the feed section to perform bar tacking 2, the length of left side zigzag stitch 1 will be one stitch. There was a problem in that the zigzag stitch 1 on the left side protruded from the shape of the buttonhole as shown in Figure 5e.

In order to avoid such distortion of the shape of the buttonhole, it is better to make the pitches 3 and 6 of the jump stitches thinner, but when adjusting the pitch of the jump stitches 3 and 6 with a thin cloth, When attempting to form buttonholes in cloth, there was a problem in that the thick cloth would slip and not be fed due to the narrow feed pitch.

Furthermore, when the pitch of the crossing stitches can be changed by manual operation, there is a problem in that the operations for the operator become complicated.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention aims to sew the overlock stitches on both sides of the buttonhole from the same direction. When a preset length has been sewn, the detection lever is activated by the buttonhole presser, the switch closes, and the buttonhole sewing machine moves on to the next buttonhole sewing operation, which detects changes in fabric thickness. The movement of the buttonhole presser, which moves up and down in response to The fabric feed pitch of the buttonhole presser is changed according to the thickness of the fabric so that the fabric feed pitch of the crossing stitch is increased.

Function According to the present invention, the thickness of the fabric is detected by detecting the vertical movement of the buttonhole presser foot, and the feed pitch of the jump stitch is changed accordingly. In this case, the small pitch of the jump stitch is selected, so there is no difference in the timing when the reversing switch is turned on, and in the case of thick fabrics that are difficult to feed, the large pitch of the jump stitch is selected. This prevents the buttonhole from being unable to be sewn due to the cloth not being fed, or from causing a defective buttonhole shape, allowing beautiful buttonholes to be sewn on both thin and thick materials.

Embodiment FIG. 1 is a side view of a part of an automatic buttonhole sewing device according to an embodiment of the present invention, and FIG. 2 is a front view of the automatic buttonhole sewing device of FIG. 1. The buttonhole presser foot 9 is supported by the lower end of a presser foot support 10 disposed on the opposite side of the needle bar 14 from the operator, and is moved toward and away from the throat plate or the feed dog 8 in two positions by means of an elevating device (not shown). It is now possible to move up and down. A detection lever 11 provided on the upper part of the buttonhole presser foot 9 is pivotally mounted so as to be rotatable in the feeding direction about a fulcrum 11a, and a tip portion 11b of the detection lever has a protrusion 12a protruding from the buttonhole presser foot 9, 12
It is located between b. These protrusions 12a, 12
The interval b is adjusted to the length of the buttonhole, and the buttonhole presser foot 9 follows the feeding movement of the feed dog 8.
When the detection lever 11 moves, the projections 12a, 1
2b, and the base end 1 of the detection lever 11
One of the switches 13a and 13b arranged opposite to each other is turned on to detect the sewing length of the buttonhole. Note that the on signals of the switches 13a and 13b are read by the central processing unit CPU25 as various operating conditions as described below. Further, a needle bar 14 is provided parallel to the presser foot support 10, and a needle 15 is supported at the lower end of this needle bar 14. Further, the needle bar 14 is supported by a swinging table 16, and is pivotally mounted by a pin 16a provided on the head 24 of the sewing machine frame 23 so as to be swingable perpendicular to the cloth feeding direction. It is connected to the arm 19 of the needle swing pulse motor 18, and the needle 1 provided on the needle bar 14 is moved by the reciprocating motion of the needle swing pulse motor 18.
5 is swung in a zigzag manner to enable zigzag stitching. Further, one end of an arm 21 of a potentiometer 20 is connected to the presser foot support 10, and a potentiometer spring 22 is connected to the other end of this arm 21. The arm 21 of the potentiometer 20 is pressed against the upper surface of the presser support 10 by a potentiometer spring 22.

FIG. 3 is a block diagram of a control device that controls the buttonhole sewing feed pitch shown in FIG. has been done. Furthermore, the input/output device I/028 is connected to the potentiometer 2 shown in FIG.
0, the switch 13 and the needle swing pulse motor 18 are connected, and the feed adjustment motor 29 of the feed dog 8 is connected.
is connected.

Next, the operation of this embodiment will be explained with reference to the flowchart shown in FIG. First, buttonhole presser foot 9
Adjust the distance between the protrusions 12a and 12b to the length of the buttonhole, lower the buttonhole presser foot 9 onto the fabric to be sewn 30, bring the tip 11b of the detection lever 11 into contact with one of the protrusions 12a, and press one switch. 1
3a is turned on. At this time, the height of the buttonhole presser foot 9 and the presser foot support 10 on which the buttonhole presser foot 9 is attached from the top surface of the throat plate 7 changes depending on the thickness of the cloth 30 to be sewn. The amount of change in height is measured by the potentiometer 20 via the arm 21.
is transmitted as the amount of rotation.

When the start switch of the sewing machine is turned on in this state (step 1), the central processing unit CPU 25 reads the rotation amount of the potentiometer 20, which changes depending on the thickness of the cloth 30 to be sewn, as a voltage, and calculates the thickness of the cloth 30 to be sewn. If it is more than x mm, the stitches are fed with a large stitch pitch, and if it is less than x mm, the stitches are fed with a small pitch stitch (step 2). As the crossing stitch progresses while repeating this operation, the buttonhole presser foot 9 moves in the feeding direction together with the cloth to be sewn 30 in conjunction with the feeding movement of the feeding dog 8, and when a predetermined length is reached,
The switch 13b is turned on via the detection lever 11 by the protrusion 12b. Upon receiving this ON signal (step 3), the feed dog 8 reverses the feed direction.
Form a zigzag left side stitch (step 4),
When the sewing machine returns to the sewing start position, the protrusion 12a turns on the switch 13a via the detection lever 11, stops sewing on the left side (step 5), moves to the right side stitch (step 6), and also switches the right side stitch to the left side. As with sewing, read the thickness of the fabric to be sewn, and if the thickness is x mm or more, feed it with a large jump stitch pitch, and if it is less than x mm, feed it with a small jump stitch pitch (step 7). When the right side running stitch is sewn to a predetermined length, the switch 13b is turned on by the protrusion 12b via the detection lever 11 (step 8), bar tacking is performed (step 9), and the right side running seam is sewn to a predetermined length. A zigzag right-hand stitch is formed in the opposite direction to the feed direction (step 10), and when the sewing machine returns to the beginning of sewing, the switch 13a is turned on via the detection lever 11 by the protrusion 12a (step 11).
A bar tacking is performed (step 12), then a tacking is performed (step 13), and the sewing machine stops (step 14).

Since the present embodiment is configured as described above, one of the two types of cross stitches, large and small, is automatically selected depending on the thickness of the cloth 30 to be sewn, so that the following effects can be obtained. In other words, in the case of thin fabrics that are easily fed, the small pitch of the crossing stitch is selected, so there is no difference in the timing when the reversing switch 13 is turned on, and there is no gap between the side stitching and the bar tacking as shown in Fig. 5d. , e, shape defects such as gaps or excessive lengths are less likely to occur. Furthermore, in the case of thick fabrics that are difficult to feed, the stitching pitch is selected to be large, which solves the problem of not being able to feed the fabric and sewing buttonholes. You can sew beautiful buttonholes on both thin and thick fabrics.

In addition, in this embodiment, the fabric thickness was determined for each stitch of crossing stitch, but it is also possible to judge the cloth thickness at the beginning of the crossing stitch process, and then perform crossing stitching at a constant pitch without making a determination. Furthermore, the fabric thickness may be determined during the entire buttonhole sewing process.

Effects of the invention As is clear from the above explanation, the present invention automatically selects one of two types of crossing stitches depending on the thickness of the fabric to be sewn. Since the small pitch of the crossing stitch is selected, there is no difference in the timing when the reversing switch is turned on, and the 5th pitch is selected between the side stitch and the bar stitch.
Shape defects such as gaps and excessive lengths as shown in Figures d and e are less likely to occur. Furthermore, in the case of thick fabrics that are difficult to feed, the stitching pitch is selected to be large, which solves the problem of not being able to feed the fabric and sewing buttonholes. It has the advantage of being able to sew beautiful buttonholes on both thin and thick fabrics.

[Brief explanation of the drawing]

FIG. 1 is a side view of a part of the automatic buttonhole sewing device according to the embodiment of the present invention, FIG. 2 is a front view of the automatic buttonhole sewing device shown in FIG. FIG. 4 is a block diagram of a control device for controlling the sewing feed pitch, FIG. 4 is a flowchart for explaining the operation of this embodiment, and FIG. 5 is a plan view of a buttonhole for explaining the drawbacks of the conventional example. 7... Throat plate, 8... Feed dog, 9... Buttonhole presser foot, 10... Presser foot support, 11... Detection lever, 12... Protrusion, 13... Switch, 14...
...Needle bar, 15... Needle, 16... Rocking table, 17...
Oscillating rod, 18... Needle swing pulse motor, 19...
Arm, 20... Potentiometer, 21... Arm, 22... Potentiometer spring, 25... Central processing unit CPU, 26... Read/write memory
RAM, 27...Read-only memory ROM, 2
8... Input/output device I/O, 29... Feed adjustment motor, 30... Cloth to be sewn.

Claims (1)

[Scope of utility model registration request] In order to oversew both sides of the buttonhole from the same direction, sew across the sides of the buttonhole just before oversewing, and when the preset length has been sewn, the buttonhole presser foot will In the buttonhole sewing machine, the detection lever is activated, the switch closes, and the buttonhole sewing machine moves on to the next buttonhole sewing operation. It is detected by a potentiometer installed on the support of the buttonhole presser, and the buttonhole presser adjusts the buttonhole presser according to the thickness of the fabric so that when the fabric is thin, the feed pitch of the jump stitch is made larger than when the fabric is thick. A buttonhole sewing feed pitch control device characterized by changing the cloth feed pitch.