JPS5913234B2 - Automatic sewing machine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for an automatic sewing machine, and more particularly to a fabric guiding means for always guiding the side edge of the fabric to a predetermined position according to a detection signal from a detector that detects the side edge of the fabric. An object of the present invention is to provide a control device for an automatic sewing machine that can drive and stop the sewing machine, raise and lower the presser foot, etc. in a purposeful manner.

An embodiment of the present invention will be described below, in which the present invention is embodied in a so-called automatic surging machine that uses an overlock sewing machine to form overlock stitches along the side edges of a fabric.

Reference numeral 1 in the figure is a table of the automatic serging machine, and an overlock sewing machine main body 2 (hereinafter referred to as the sewing machine main body) is placed on the table 1.

The sewing machine main body 2 includes a needle 3 that moves up and down, and a cloth feed mechanism including a presser foot 5 and a feed dog 6 for transporting the cloth 4 in one direction on its supporting surface across the vertical movement path of the needle 3. It is equipped with

Also. The feed dog 6 passes through a throat plate 7 and moves up and down, and a cloth plate 8 is provided so as to be flush with the throat plate 7. 4 support surfaces are constructed.

Reference numeral 9 denotes a presser foot lifting lever whose intermediate portion is rotatably supported on the sewing machine main body 2 by a shaft 10, and supports the presser foot 5 at one end.

Reference numeral 11 denotes a presser foot coil spring provided between the presser foot lifting lever 9 and the sewing machine main body 2, which applies presser pressure to the presser foot 5.

Reference numeral 12 denotes an air cylinder for lifting the presser foot, which is fixed to the sewing machine body 2 or table 1, and its rod 13 is connected to the chain 1.
4 to the other end of the presser foot lifting lever 9.

Reference numeral 15 denotes a face edge cutting device for cutting the side edges of the fabric 4, but in such a serging machine, the fabric is cut into a desired shape before sewing, and the edges of the fabric are not cut.

Reference numeral 16 denotes a motor with a clutch attached to the underside of the table, and is of a known type that increases the clutch interlocking and breaking impulse by 1 when the clutch lever 18 is operated. This is performed by a driving air cylinder 18 provided between the clutch motor 16 and the bracket.

The output of the motor 16 is transmitted to the sewing machine main body 2 via a belt 19.

Further, a first detector for detecting the side edge 4a of the fabric 4 is provided on the fabric feeding side with respect to the needle 3.

The first detector includes a detection element 20 including a light emitter 20a and a light receiver 20b, and a reflecting section 21 provided on the cloth plate 8 for reflecting light from the light emitter 20a toward the light receiver 20b. Consisting of

Further, the detection element 20 is attached to a mounting plate 22 fixed to the sewing machine main body 2.

Reference numeral 23 denotes a servo motor which is rotated forward and backward by a signal from the light receiver 20b of the first detector, and is attached to the lower surface of the cloth plate 8, and a rotating ring 24 is attached to its output shaft.

The rotating wheel 24 is rotated around an axis parallel to the cloth feeding direction, and its upper end slightly protrudes through an opening 25 formed in the cloth plate 8, as is clear from FIG.

A presser support arm 26 is rotatably supported by a shaft 28 on a support 27 fixed on the cloth plate 8, and a presser foot 28 that cooperates with the rotary ring 24 is attached to one end.

Reference numeral 29 denotes a presser spring that applies rotational force in the counterclockwise direction of FIG. 4 to the presser support arm 26.

Reference numeral 30 denotes a presser foot lifting air cylinder fixed to the sewing machine main body 2 or table 1, and its rod 31 is connected to the other end of the presser foot support arm 26.

Furthermore, a second detector is located on the cloth feeding side of the needle 3 and spaced from the cloth feeding direction line passing through the first detector inside the cloth side edge 4a for detecting the presence or absence of the cloth 4. Detectors are provided.

The second detector includes a detection element 31 including a light emitter 31a and a light receiver 31b, and a reflecting section 32 provided on the cloth plate 8 to reflect the light from the light emitter 31g toward the light receiver 31b. The detection element 31 consisting of the following is attached to the mounting plate 22.

Note that the second detector is located closer to the cloth feeding side than the first detector.

33 is a first amplifier added to the light receiver 20b of the first detector, which generates a high level when the side edge 4a of the fabric 4 blocks half of the light from the light emitter 20a on the reflector 21; When the fabric 4 is not present and all the light from the light emitter 20a enters the light receiver 20b, a low level output voltage is generated.

Reference numeral 34 denotes a second amplifier added to the light receiver 31b of the second detector, which generates a high level output voltage when the fabric 4 blocks the light from the light emitter 31a. When the light from the light emitter 31a enters the light receiver 31b, a low level output voltage is generated.

35 is an AND circuit which receives the outputs from the first and second amplifiers, and 36 is a flip-flop constituted by two OR circuits 37 and 38.

The output from the AND circuit 35 is input when the output from the AND circuit 35 and the output from the second amplifier circuit 34 are input, and the second and second detectors both detect the presence of the fabric 4. is set so that a high level output voltage appears at its output terminal 39, and is reset when the second detector detects passage of the fabric 4, and a low level output voltage appears at its output terminal 39. be exposed.

40 is the presser foot lifting air cylinder 30. which is operated based on the output of the flip-flop 36. A control means that opens and closes electromagnetic valves attached to the presser foot lifting air cylinder 12 and the driving air cylinder 18 to control the introduction and evacuation of air to these air cylinders, and the flip-flop 36 is set. When a high level output voltage appears at the output terminal 39 of the lever, the presser foot 28 is lowered by the presser spring 29, the presser foot 5 is lowered by the cloth presser coil spring 11, and the driving air cylinder 18 is lowered. When the flip-flop 36 is reset and a low level output voltage appears at the output terminal 39, the reverse operation is performed. let

The first amplifier 33 also sends a drive signal to the servo motor 23, and its rotating wheel 24 and presser foot 28 cause the side edge 4a of the fabric 4 to receive light from the light projector 20a of the first detector. (on the reflecting section 21).

Next, the effect will be explained.

When the power is turned on, the light projectors 20a in the first and second detectors.

All the light from 31a enters the receivers 20b and 31b, respectively, the output voltages of the first and second amplifiers 33 and 34 are both at a low level, and the flip-flop 36 is reset and its output terminal 39 has a low level. Level output is displayed.

Therefore, the presser foot support arm 26 is rotated by the presser foot lifting air cylinder 30 against the action of the pressing spring 29, and the presser foot 28 is raised, and the presser foot lifting air cylinder 1
2, the presser foot lifting lever 9 is rotated against the action of the coil spring 11 for the presser foot, and the presser foot 5 is raised, and furthermore, the introduction and discharge of air to the drive air cylinder 18 is controlled, and the clutch is attached. The clutch lever 17 of the motor 16 is operated, the clutch is disengaged, and the driving of the sewing machine body 2 is stopped.

In this state, the cloth 4 is inserted, and the cloth 4 covers the reflecting portions 21 and 32 of the first and second detectors (that is, the light from the respective projectors 20a and 31a) as shown in FIG. 6a. When the output voltage becomes high, both the output voltages of the first and second amplifiers 33 and 34 become high level, which is applied as an input to the AND circuit 35, and the output of the AND circuit causes the flip-flop 36 to be activated. When set, a high level output voltage appears at its output terminal 39.

Thereby, contrary to the above, the presser foot 28 is moved by the presser spring 29.
is lowered onto the rotating wheel 24, and the presser foot is lowered by the coil springs 1, 1 for the presser foot, and the clutch lever 17 is actuated via the drive air cylinder 18.The clutch of the clutch motor 16 is activated. Once connected, the sewing machine main body 2 is driven.

Those presser feet28. It is necessary that there is a timing delay between the lowering of the presser foot 6 and the driving of the sewing machine.

Therefore, even if the shape of the side edge 4a of the fabric 4 changes while sewing continues, the light is reflected from the light emitter 20a1 by the reflecting part '21, and the light is reflected from the light receiver 2Q.
The amount of light entering b changes and is applied to the servo motor 23, which rotates the motor forward and backward. ) and an overlock seam is formed along its edge.

Now, suppose that due to a sudden change in the curve of the side edge of fabric 4, the 6th
As shown in the figure, when the side edge 4a of the first detector deviates from the center of the light from the projector 20-a and the output voltage of the first amplifier 33 becomes low level, the AND circuit 3
5 becomes a low level and a high level, and the output of the AND circuit changes, but an output voltage of a lower level than the OR circuit 38 is applied to one input terminal of the OR circuit 37 of the flip-flop 36. Therefore, the output state of this flip-flop 36 does not change.

However, as shown in FIG. 6C, when the sewing is nearing completion and the end of the fabric 4 passes over the reflecting part 21 of the first detector, the light from the emitter 31a is transmitted to the receiver 31b. As a result, a low level output appears at the second amplifier 34, which resets the flip-flop 36.

Therefore, a low level output voltage appears at the output terminal 39 of the flip-flop 36.

By the same action as when the power is turned on, the presser foot 28. The presser foot 5 is raised, the clutch of the clutch motor 16 is disconnected, and the driving of the sewing machine body 2 is stopped.

When the end of the fabric 4 is detected by the first detector, there is still a slight unsewn part, so such a presser foot 28. It is necessary to raise the presser foot 5 and stop the sewing machine body 2 with a delay after the end of the fabric 4 is detected.

The present invention has the configuration as described above in detail: a first detector for detecting the side edge of the fabric; A control means lowers the presser foot based on the output when a second detector installed on the inside for detecting the presence or absence of cloth both detects the presence of cloth, and a means for driving the sewing machine body. Since the sewing machine is enabled, the sewing machine will only be driven when the fabric is fed to the correct sewing position, and if the fabric is fed at an angle, for example, the sewing machine will not be driven, and therefore the sewing machine will not be able to operate. It does not produce good quality products.

Moreover, since the sewing machine starts driving as soon as the fabric is fed to the correct position, work efficiency is improved.

Furthermore, based on the output when the second detector detects the passing of the fabric, the sewing machine is stopped and the presser foot is raised, contrary to the above, through the control means. Even if the curve of the side edge of the sewing machine suddenly changes and the side edge begins to come off the first detector, the sewing machine will not stop unexpectedly, and so on.

BRIEF DESCRIPTION OF THE DRAWINGS - Fig. 1 is a front view, Fig. 2 is a side view of a seam forming part partially shown in cross section, and Fig. 3 is a plan view of the same part.

FIG. 4 is a cross-sectional view of the fabric guide means taken along the IT-IT line in FIG. 2, FIG. 5 is a control circuit diagram, and FIGS. 6 a to C.
is an action explanatory diagram.

In the figure, 2 is the sewing machine body, 3 is the needle, 4 is the fabric, 4a is the side edge of the fabric, 5 is the presser foot, 12 is the air cylinder for lifting the presser foot, 16 is the motor with a clutch, 18 is the driving air cylinder, 20 is a detection element consisting of a light projector 20a and a light receiver 20b, and 21 is a reflection section.

23 is a servo motor, 24 is a rotating wheel, and 28 is a presser foot.

30 is an air cylinder for lifting the presser foot; 31 is a detection element including a light emitter 31a and a light receiver 31b; 32 is a reflecting section; 33,3
4 is a first and second amplifier, 35 is an AND circuit, 36 is a flip-flop, 37.degree. 38 is an OR circuit, 39 is an output terminal, and 4'0 is a control means.

Claims (1)

[Scope of Claims] 1. A sewing machine equipped with a needle that moves up and down and a fabric feed mechanism that includes a presser foot and a feed dog for transferring the fabric in one direction on its supporting surface across the vertical movement path of the needle. With the main body. A driving means for driving the sewing machine main body; and an elevating and lowering operation means for elevating and lowering the presser foot of the sewing machine main body. a first detector located on the cloth feeding side of the needle for detecting a side edge of the cloth; fabric guiding means for always guiding the side edge of the fabric to a predetermined position according to a detection signal from the first detector;
A second detector located on the cloth feeding side relative to the needle and spaced from the cloth feeding direction line passing through the first detector inside the side edge of the cloth, for detecting the presence or absence of the cloth. and a detector of ′
Based on the output when both the second and second detectors detect the presence of the fabric, the presser foot is lowered via the lifting/lowering actuating means and the driving means is activated to start the sewing machine. A control device for an automatic sewing machine, characterized in that it is provided with a control means for driving and performing an operation opposite to the second detector based on an output when the passage of the cloth is detected.