JPH0453584A - Seam formation switching device in overlock sewing machine - Google Patents

Abstract

PURPOSE:To dispense with difficult adjustment of thread tension and easily switch seam formation during sewing by movably forming a thread guide relatively holding a needle thread to a thread take-up lever so that it is stretched by the needle thread take-up lever, and changing the position of a thread guide according to plain seam and hemming seam. CONSTITUTION:As a needle thread guide 7 is ordinarily situated in a lower position and the delivery quantity per stitch is small, a sewing machine is laid in plain seam state (in which needle thread is fastened). However, when an electromagnetic solenoid 16 is energized to rotate a lever 13 counterclockwise through a link 17, the needle thread guide 7 is raised to form a state in which a needle thread take-up lever 6 draws a needle thread 8 downward. Thus, the tension of the needle thread is increased, and the delivery quantity per stitch of the needle thread is increased to form hemming seam state (in which the needle thread is loosened). When an index lock pin 18 is manually moved along the scale of a scale plate 19 without energizing the electromagnetic solenoid 16 and locked in an optional position, plain seam, hemming seam, or an optional needle thread fastening state between them can be formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a seam formation switching device in an overlock sewing machine, and particularly to a seam formation switching device in an overlock sewing machine that forms a hem stitch following a base stitch in a sewing process. This invention relates to a switching device.

[Conventional technology]

Conventionally, switching between US seam standard 504 (base stitch) and 505 (hemming stitch) was generally done by changing the thread tension, and the adjustment was made by stopping the sewing machine drive. . Therefore, in order to prevent the sewing work from being interrupted, we decided to
0-26787, in which two thread tension devices are arranged in series in the thread path and the tension is varied by temporarily releasing the thread clamping pressure of one of the thread tension devices;
Like the one in Japanese Utility Model Publication No. 60-26787, the first thread tension device group is composed of first thread tension devices for the needle thread and looper thread, and the second thread tension devices for the needle thread and looper thread. The first thread tension regulator group and the second thread tension regulator group, which are set to have different thread supply ratios for the needle thread and the looper thread, can be used, for example, when performing plain stitching. An electromagnetic solenoid is used to switch between forming an empty ring and forming an empty ring during sewing.

[Problem to be solved by the invention]

However, in all of the above-mentioned conventional devices, the disadvantage is that the number of thread tension devices that are attached means that the stitches are switched, making it easy to thread the thread incorrectly, making it difficult to adjust the timing for lifting the thread tension disc, etc., and requiring a large number of parts, resulting in high costs. was there.

The present invention seeks to eliminate the above-mentioned drawbacks.

[Means to solve the problem]

The stitch formation switching device in the Ohharo 7 sewing machine of the present invention has a thread guide that holds the needle thread relative to the needle thread take-up movable so as to be pulled by the needle thread take-up, and the position of the thread guide is set to the basic sewing machine. , is characterized in that it changes depending on the deferred stitching.

[For production]

In the stitch formation switching device for the overlock sewing machine of the present invention, by moving the needle thread guide, the thread tension is changed and the stitch formation is switched.

〔Example〕

The present invention will be explained in detail below with reference to the drawings.

In Figures 1 and 2, 1 is an overlock sewing machine, 2
is a control box, 3 is a pulley driven by a sewing machine motor, 3a is a stitch count detector built into the pulley 3 that generates one pulse every time the pulley 3 rotates once, 4 is a fabric detection sensor (light emitting element), 5 6 is a light receiving sensor; 6 is a needle thread take-up having a hook portion 6a formed at one end and the other end is fixed to a needle holder; 7 is a needle thread guide; 8 is a needle thread inserted into the needle via the needle thread guide 7;
9 is a needle, 10 is a needle clasp, 11 is a needle clasp stand, 21.22.23
is a thread tension provided in the threader feeding the needle 9 and the left and right loopers (not shown). The movement of the needle 9 is caused by the vertical movement of an operating arm that swings via a crank connected to a main shaft (not shown), so that the needle holder base 11 moves up and down along the needle holder guide rod 11a to perform linear movement. It has become. In the present invention, the needle thread guide 7 is held by the outer casing 12 of the sewing machine so as to be movable up and down, and the intermediate portion of the lever 13 is rotatably supported on the outer casing 12 via a pivot screw 14. As shown in FIG. 3, one end of this lever 13 and the upper end of the needle thread guide 7 are connected to each other by a link 15, and an electromagnetic solenoid 16 is attached to the outer case 12, and a plunger 16 of the electromagnetic solenoid 16 is attached to the outer case 12. ' and the other end of the lever 13 are connected by a link 17.

Further, if necessary, an index lock pin 18 is implanted in the lever 13, and the index lock pin 18 is inserted into the arcuate groove 20 of the scale plate 19 fixed to the outer case 12.
The curvature of the index lock pin 18 is made to match the trajectory followed by the index lock pin 18 when the lever 13 rotates around the stepped screw 14.

Since the stitch formation switching device in the overlock sewing machine of the present invention has the above-mentioned configuration, the needle thread guide 7 is always in the lower position as shown in FIG. 3, and the amount of feed per stitch is small. , the sewing machine is in the ground sewing state (the needle is threaded), but if the electromagnetic solenoid 16 is energized and the lever 13 is rotated counterclockwise via the link 17, the needle thread guide 7 will rise, and the needle The thread take-up 6 becomes as shown in Fig. 4, and the needle thread 8
is in a state where it is pulled downward, and as a result, the tension of the needle thread increases and the amount of needle thread fed out per stitch increases, resulting in a state of hemming stitch (needle thread loosening). FIG. 5 shows a ground stitch, a hem stitch, and a seam in which a hem stitch is formed following the ground stitch.

Furthermore, by manually moving the index locking pin 18 along the scale of the scale plate 19 and locking it at a desired position without energizing the electromagnetic solenoid 16, base stitching, hemming stitching, or any needle thread between them can be performed. It can be made into a fluffy state.

The electromagnetic solenoid 16 is controlled by the control box 2. That is, the control box 2 detects cloth using the cloth detection sensor 4, and detects the cloth using the counting detector 3.
When the number of stitches detected from the above reaches a predetermined value, the electromagnetic solenoid 16 is energized.

By doing this, the stitches will be automatically changed at a predetermined point during sewing. For example, in the case of long-sleeved underwear shown in Figure 6, A-B will be hemmed and B-C will be hemmed. When sewing with ground stitching, the quality of the sewing improves because it fits the skin and the needle thread has a good flow.

[Effects of the Invention] As described above, according to the seam formation switching device of the overlock sewing machine of the present invention, there is no need for difficult adjustments such as thread tension, and it is extremely easy to switch the seam formation, and this can be done even during sewing. In addition, there are various benefits such as improved quality of the sewing material by switching the stitches.

Arc groove, 21, 22° 23... Thread tension

[Brief explanation of drawings]

Fig. 1 is a perspective view of a sewing machine equipped with a stitch forming switching device in an overlock sewing machine of the present invention, Fig. 2 is a detailed view of the needle clasp, and Fig. 3 is a stitch forming in an overlock sewing machine of the present invention. FIG. 4 is an explanatory diagram of the switching device, FIG. 4 is an explanatory diagram of its operation, FIG. 5 is an explanatory diagram of stitches, and FIG. 6 is an explanatory diagram of a sewn product.

Claims (1)

[Claims] A thread guide for holding the needle thread relative to the needle thread take-up so as to be pulled by the needle thread take-up is movable, and the position of the thread guide is changed depending on whether the needle thread is being sewn by the thread take-up or the thread take-up. Stitch formation switching device for overlock sewing machines.