JPS5820231Y2 - Sewing machine cutter control device - Google Patents

Description

[Detailed description of the invention] This invention controls a cutter placed on the cloth feeding side near the seam forming point in order to cut loops, tapes, etc. that are connected to the front or rear edge of the sewn workpiece cloth. This invention relates to improvements to control devices for the purpose of

Conventionally, in this type of control device, a detection device for detecting the front edge or the rear edge of the workpiece cloth is placed near the seam forming point, and the cutter is operated after the output signal of the detection device is generated and the cutter is moved. There has been provided a device which is operated to cut the loop, tape, etc. that are continuous to the front edge or the rear edge of the cloth to be processed, and which can adjust the time from the generation of the detection signal to the operation of the cutter.

However, the conventional device has the following deficiencies.

That is, in the conventional device, for example, FIG.
When sewing a workpiece cloth whose front end shape is constant in the cloth feeding direction as shown in ,
By appropriately adjusting the setting time of the timer circuit from the generation of the front edge signal of the workpiece cloth until the cutter operation, the cutter is activated after a predetermined time 11.12 has elapsed from the generation of the detection signal, and the cutter is connected to the workpiece cloth. The length of the empty ring portion ΔL can be made constant.

However, when sewing a workpiece cloth whose front end shape is shown in FIG. 3A and a workpiece cloth shown in FIG. It is necessary to perform this adjustment every time the shape is changed, and the work efficiency is greatly reduced. If the adjustment is neglected, for example, the setting time t1 of the timer circuit suitable for the workpiece cloth shown in Fig. 3a may remain unchanged. When the workpiece cloth shown in Figure 3C is sewn, the front end of the workpiece cloth may be cut as shown in Figure 3C, or the length of the hollow ring connected to the front edge of the workpiece cloth may be uneven. It has defects such as

The present invention solves the above-mentioned defects and improves the cutter control circuit so that the work efficiency does not decrease even when randomly sewing workpiece cloths of different shapes. The details will be explained with reference to FIGS. 1 to 4a and 4b showing the embodiment.

In the figure, 1 is the head of an overlock sewing machine (hereinafter abbreviated as the sewing machine), which is placed on a table 2.

3 is a sewing machine needle, 4 is a throat plate, 5 is a feed dog, and 6 is a presser foot.

A fixed blade 7 is embedded in the table 2 on the cloth feeding side from the throat plate 4, and works in cooperation with a cutter 8 that rotates in a vertical plane to cut the empty ring part connected to the front edge of the workpiece cloth during sewing. do.

Reference numeral 9 denotes a rotation shaft rotatably attached to the sewing machine, and the cutter 8 is fixed to one end of the rotation shaft, and a pinion 10 is fixed to the other end.

A solenoid 16 is fixed to the side surface of the sewing machine head, and its solenoid shaft 14 is connected to a rack 11 via a coupling 12, and the rack 11 meshes with the pinion.

A spring 13 pushes the rack 11 downward while the solenoid 16 is not energized, so that the cutter 8 is held in the position shown in FIGS. 1-2.

15 is a flange attached to both ends of the spring 13;
7.18 is a rotary shaft holder for holding the rotary shaft 9 and fixing it on the table 2; 19 is a rotary shaft holder for holding the rotary shaft 9 and fixing the rotary shaft 9 on the table 2; This is an air suction tube for suctioning and making it easier to cut.

20 is an optical sensor holder fixed on the table 2;
Reference numeral 21a denotes a reflective optical sensor for detecting the front end or rear end of the cloth to be processed, and is attached to the lower surface of the optical sensor holder 20.

Reference numeral 21b denotes an optical sensor installed in parallel with the optical sensor 21a in a direction perpendicular to the cloth feeding direction with respect to the optical sensor 21a.

The control section of this embodiment is shown below in Fig. 4a, Fig. 4b,
This will be explained with reference to FIGS. 5a and 5s.

30 is the optical sensor 21a, 21b, OR circuit 31
．． .

and an AND circuit 32, the OR circuit 3
1 is the output terminal P1.1 of the optical sensor 21a, 21b.
P2, and when either one of the optical sensors detects the front end of the cloth to be processed, l is output to its output terminal, and the AND circuit 32 is connected to the output terminals of the optical sensors 21a and 21b, and outputs the light When both sensors 21a and 21b detect the front end of the cloth to be processed, 1 is output to their output terminals.

33 is a control circuit serving as a timer means for determining the timing of operation of the cutter 8;
first and second timer circuits 34 connected to the output terminals of
．． 35, and their timer circuits are OR circuits 31
The output signal is generated at a set time after the input of the output signal from the sewing machine, and the set time is based on the feed speed of the sewing machine, the distance from the sewing machine needle 3 to the cutter 8, the shape of the workpiece cloth, etc. Adjusted arbitrarily.

36 is a selection circuit which determines which of the cutter operation start signals outputted from the timer circuits 34 and 35 is to be supplied to a cutter drive device to be described later, and includes a cloth edge shape identification circuit 37, a changeover drive circuit 38, and a changeover switch. 39.

The cloth edge shape identification circuit 37 includes a timer circuit 40, an AND circuit 41, and a flip-flop 42, and the timer circuit 40 is triggered by the output of the OR circuit 31 and outputs 1 to its output terminal for a set time t3, and The AND circuit 41 is connected to the output terminals of the timer circuit and the AND circuit 32, and inputs the pulse P3 to the input terminal of the flip-flop 42 only when there is an output from both of them.

That is, when both the optical sensors 21a and 21b detect the front end of the workpiece cloth within the set time 13, in other words, when the front end of the workpiece cloth is perpendicular to the cloth feeding direction or in a shape close to it, the pulse is generated. P3 is input to the input terminal of the flip-flop 42.

The switching drive circuit 38 inputs the Q output of the flip-flop 42 and switches the changeover switch 39, and the movable contact 39a of the switch 39 always receives a signal from the first timer circuit 34, which will be described later. It is connected to the fixed contact 39b side so as to supply the cutter drive circuit, and is connected to the fixed contact 39C side by the actuation signal from the switching drive circuit 38, and at this time, the signal from the second timer circuit 35 is connected to the cutter drive circuit. Supplied to the drive circuit.

Note that 43 is a relay for operating the changeover switch 39.

Therefore, according to this embodiment, when the front end of the cloth to be processed is perpendicular to the feeding direction or close to the shape, the changeover drive circuit does not operate and the changeover switch 39 remains in its state and the first
After the time set by the timer circuit has elapsed, a cutter operation start signal is supplied to the cutter drive circuit, and the switching drive circuit 38 is activated only when the front end of the workpiece cloth has a shape as shown in FIG. 3C. Then, the changeover switch 39 is switched, and after the time set by the second timer circuit has elapsed, a cutter operation start signal is supplied to the cutter drive circuit.

Note that 44 is a cutter drive circuit connected to the selection circuit 36, which connects the solenoid 16 and the solenoid drive circuit 45.
As described above, the solenoid drive circuit is connected to the changeover switch 39 and drives the solenoid 16 for a predetermined period of time by a monostable multivibrator built into the circuit.

The operating mode of this embodiment configured as described above will be explained with particular reference to FIGS. 3a and 3c.

First, the workpiece cloth W is set between the presser foot 6 and the feed dog 5, and sewing is started based on a sewing start command signal (not shown) to form a hemline stitch on the workpiece cloth W.

In this case, the front end of the workpiece cloth W has a series of empty rings left from the previous sewing, and these empty rings are connected to the air suction pipe 1.
9 into the tube.

As shown in FIG. 3a, when the front end of the workpiece cloth W is perpendicular to the feeding direction, both optical sensors 21a and 21b detect the front end of the workpiece cloth W almost at the same time.

Therefore, the shape of the cloth W to be processed is identified by the cloth edge shape identification circuit 37, and since the changeover switch 39 cannot be switched in this case, the timer circuit of the wool 1 is activated after the front edge of the cloth to be processed is detected by the optical sensors 21a and 21b. After the time t0 set by 34 has elapsed, the solenoid 16 is actuated by the solenoid drive circuit 45, and based on this, the cutter 8 is actuated to cut the empty ring.

The set time t1 of the timer circuit 34 is set, taking into consideration various conditions as described above, such that the empty ring is cut leaving a small amount of the empty ring ΔL at the front end of the workpiece cloth W.

Next, when the shape of the cloth to be processed is as shown in FIG.
After a lapse of (very short time), the optical sensor 21b detects the front end of the cloth W to be processed.

Based on the detection signal, the shape of the workpiece cloth W is identified by the cloth edge shape identification circuit 37, and in this case, the changeover switch 39 is changed over, so that after the set time t2 set by the second timer circuit 35 has elapsed, the solenoid The solenoid 16 is actuated by the drive circuit 45, and the cutter 8 is actuated based on the solenoid 16 to cut the empty ring.

Note that the set time t2 of the second timer circuit 35 is set so as to leave a slight empty ring at the front end of the workpiece cloth W and cut the empty ring, as in the case of the first timer circuit 34. As is clear from the drawing, when the front end is detected by the optical sensor 21a, the tip on the side where the seam is formed is located at the front end of the optical sensor 21a.
Since the second timer setting time t2 is located further on the cloth feeding side than the position 21a, the second timer setting time t2 is smaller than the setting time t1 of the first timer circuit 34.

Note that if the set time t2 of the second timer circuit 35 is made the same as the set time t1 of the first timer circuit 34, the edge of the workpiece cloth W will be cut as shown in FIG. 3. need not be explained in detail.

In this embodiment, the timer circuit is selected to operate the cutter depending on the shape of the front end of the workpiece cloth W, but if necessary, the cutter can also be operated for the rear end of the workpiece cloth W. It is possible to control the timing of cutter operation depending on the shape difference.

Further, in this embodiment, a timer circuit is provided which is activated after generation of one of the detection signals from the two detection elements, and the cutter actuating device is activated based on the timing signal from the timer circuit. Although the start timing is determined, a counting circuit is provided to count the number of stitches to be sewn after the detection signal is generated, and the timing to start driving the cutter actuating device is controlled based on the counting result. Also, although we have shown an example in which two optical sensors arranged apart in a direction perpendicular to the cloth feeding direction are used as detection elements for the shape identification means of the cloth to be processed, these two
The optical sensors do not necessarily need to be arranged in orthogonal directions, and may be arranged at the front or rear end of the workpiece cloth using other detection devices such as image sensors that have a large number of detection elements. The object of the present invention can also be achieved by identifying the shape.

As described in detail above, the present invention includes a shape identification means that includes two detection elements for detecting the front end or the rear end of the workpiece cloth and is capable of identifying the shape of the front and rear ends of the workpiece cloth, and a shape recognition means that includes This system is equipped with a control means that controls the timing of the start of operation of the cutter actuating device in response to the identification result of This has an excellent effect of completely eliminating accidents such as the cutter being operated at the time of operation and cutting the front and rear ends of the cloth to be processed, or the lengths of the empty rings becoming uneven.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing the main parts of this device, FIG. 2 is a partial plan view thereof, and FIGS. 3 a, 1), and c are views showing examples of sewing workpiece cloths of different shapes. Figure 4a is a block diagram showing the control section of this device, Figure 4 is a timing chart showing the operation of its main parts, and Figure 5a is a diagram showing specific circuits of the detection circuit, shape identification circuit, and switching drive circuit. The figure shown in FIG. 5 is a timing chart showing the operation of the main part thereof. 1 is the sewing machine head, 3 is the needle, 7 is the fixed blade, 8 is the cutter,
16 is a solenoid, 21a and 21b are optical sensors
, 34 is a first timer circuit, 35 is a second timer circuit,
37 is a cloth edge shape identification circuit.

Claims (1)

[Scope of utility model registration request] 1. A cutter placed on the cloth feeding side in the cloth feeding direction in the vicinity of the seam forming point to cut a hollow ring etc. sewn to the front edge or rear edge of the workpiece cloth, and a cutter for operating the cutter. A sewing machine comprising an actuating device and configured to automatically cut an empty ring, etc. sewn to the workpiece cloth at the start or end of sewing, the sewing machine comprising: It includes at least two detection elements arranged apart from each other in a direction intersecting the cloth feeding direction to detect the front edge or the rear edge of the fabric to be processed based on detection signals from the two detection elements. A shape identification means for identifying the shape of the front end or the rear end, and a control means for controlling the timing of starting the operation of the cutter actuating device in response to the shape identification result of the workpiece cloth identified by the shape identification means. A sewing machine cutter control device characterized by: 2. The control means includes a timer circuit that generates at least two types of timing signals in relation to the generation of one of the detection signals from the two detection elements, and a shape recognition means from the shape recognition means. A selection control device that selects one of the two types of timing signals in response to the result and drives the cutter actuating device based on the selected timing signal. A cutter control device for a sewing machine according to claim 1.