JPH0112517B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in an automatic sewing machine that stores pattern data in a storage medium and reads out this data to form a stitch pattern.

[Prior art]

Conventionally, there has been a device of this type as shown in FIG. In the figure, 1 is a sewing machine, 2 is a two-axis drive device for moving the presser foot device 4 according to predetermined pattern data, 3 is a sewing machine table, and 4 is a device that clamps the workpiece (sewn material) using air pressure. , a presser foot device driven by a two-axis drive device 2; 5 a storage medium storing preprogrammed pattern data; 6 a storage medium 5;
A control device for controlling the shaft drive device 2, 8A,
8B is an operating device for operating the drive of the automatic sewing machine, 9 is a power switch, and 10 is a two-axis drive device 2.
11 is a test switch that drives the two axes according to the sewing data without moving the needle of the sewing machine. Reference numeral 12 is an origin detection device that detects the mechanical origin of the two axes. 14 is a start switch for starting sewing; 15 is a motor for the sewing machine; 16 is an intermediate stop switch; and 17 is a presser foot switch for clamping and releasing the presser foot device.

18 is a detector that indicates the sewing machine needle bar position, 19 is a thread cutting device, 54 is a solenoid for driving this, 25
is a thread cutting mechanism driven by this solenoid.

Next, the operation will be explained.

First, the power switch 9 included in the operating device 8B
to start the sewing machine motor 15. Next, the reset switch 10 is operated to drive the two-axis drive device 2 and move the presser foot device 4 to a position predetermined by the origin detection device 12 (hereinafter referred to as the machine origin). Next, when the workpiece is held between the presser foot device 4 and the start switch 14 is operated, the sewing machine 1 and the two-axis drive device 2 are driven according to the predetermined pattern data programmed in the storage medium 5, and the workpiece is The presser device 4 moves the workpiece to form stitches. When the sewing is finished, the sewing thread is automatically cut by the thread cutting device 19, the sewing machine 1 is stopped, and the presser foot device 4, which is driven by air pressure, releases the clamping of the workpiece. These series of operations are controlled by the control device 6. The pre-programmed pattern data is moved from the machine origin to the sewing start position by jump feed (without driving the sewing machine) to start sewing, and when the sewing is finished, it is sent as an end command for the pattern data in the storage medium 5. At the same time, the machine is moved to the machine origin by the origin detection device 12 of the automatic sewing machine body and then stopped. This program consists of a series of operations from the start to the end of sewing, and can be stopped midway through sewing by operating the midway stop switch 16.

In order to stop the needle in the upper position after thread trimming, the conventional automatic sewing machine uses a needle position detector 18 as shown in FIG. 3 to stop the needle in the upper position after thread trimming. Generally, the control circuit is configured to operate the thread trimming solenoid 54 until the position signal 41 is reached. Therefore, if the thread gets tangled in the thread trimming mechanism 25 or if the sewing machine cannot rotate from the needle down position 40 to the needle up position 41 for some reason, the thread trimming solenoid 54 will remain energized, resulting in burnout of the solenoid. It had the disadvantage of inviting

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it is a safety feature that can prevent the solenoid from burning out by automatically turning off the power within a certain period of time after the thread trimming solenoid is activated. The purpose is to provide an automatic sewing machine incorporating the device.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

The figure specifically shows the control device section 6 of the automatic sewing machine, and 20 is its central control device.
The CPUs 20 and 21 are PROMs in which system control programs are stored in advance, and 22 is a RAM that operates as a stack RAM for the CPU 20.

Although conventional devices have such a basic configuration, in this invention, in particular, the above-mentioned PROM 21
In addition to a storage section for a system control program for performing normal sewing as in the past, it also has a storage section for a counter program as a timer.

Next, the operation will be explained.

Taking the sewing pattern shown in Fig. 4 as an example, 30 is the sewing area of the automatic sewing machine, 31 is the machine origin of the automatic sewing machine, the broken line represents the needle position moving by idle feed without sewing, and the solid line represents the sewing pattern. shows the trajectory of actual sewing.

In a series of operations, by operating the start switch 14, the CPU 20 sequentially reads out the sewing data having the bit configuration shown in FIG. The cloth is moved by , the needle position is moved from the machine origin 31 to point 32 by idle feed, and the sewing machine is rotated from points 33 to 35 and 36 by the sewing machine motor 15 to perform actual sewing. Next, when the CPU 20 reads the thread cutting code shown in FIG. 6 stored in the storage medium 5 at the position of point 36,
The system control program written in the PROM controls the sewing machine motor 15 at a thread cutting speed of approx.
2-axis drive device 1.
0 is fixed at the position of point 36, and the needle bar position detector 1
The needle lower position 40 is read from 8, the thread trimming solenoid 54 is operated, and the thread trimming mechanism 25 is driven.

The operations up to this point are performed in the same manner as in the conventional device, but in the device of the present invention, as shown in FIG. 7, the operation of the thread trimming solenoid 54 is controlled by the needle bar position detector 18 as shown in FIG. The rotation continues in the direction of the arrow until the needle top position 41 is read by the CPU 20, and the needle bar position detector 18 is set at 200 rpm.
Since the thread cutting solenoid 54 is rotated by the thread cutting solenoid 54, it is meaningless to energize it for more than a certain period of time and will only cause burnout of the solenoid. That is,
The CPU 20 reads the counter program from the counter program storage section in the PROM 21, operates the solenoid 54, and starts counting from the time when the thread cutting mechanism 25 starts to be driven, and when this count becomes constant, A timer is configured to issue a signal to stop energizing the solenoid 54, giving priority to the above-mentioned stop control during normal thread cutting.

Although the above embodiment shows the case when the thread trimming code is read, the counting operation is similarly started when the midway stop switch 16 is operated and the thread trimming operation is performed in the middle of sewing. , the power supply to the solenoid is stopped. Furthermore, it is also possible to control the solenoids in exactly the same way for those that perform not only thread cutting but also wiper operation.

〔Effect of the invention〕

As described above, according to the present invention, since the timer means is provided by a program for the energization time of the thread trimming solenoid, the solenoid is activated in the event of an abnormal condition such as a malfunction of the thread trimming mechanism or a case where the needle top position signal is not transmitted. It is possible to prevent burnout, and there is an effect that the safety of the control circuit of an automatic sewing machine can be improved at a low cost.

[Brief explanation of drawings]

Figure 1 is an external view of a conventional automatic sewing machine, Figure 2
FIG. 3 is a block diagram showing a specific configuration of a control section in an embodiment of the present invention, FIG. 3 is an external view showing a needle bar position detector portion, FIG. 4 is a diagram showing a specific example of a sewing pattern, and FIG. 6 shows the bit structure of the sewing data, FIG. 6 shows the bit structure of the thread cutting code, and FIG. 7 shows a flowchart of the main operations. In addition, in the figure, 5 is a storage medium, 20 is a CPU, 21
1 is a PROM, 10 is a two-axis drive device, 15 is a sewing machine motor, 54 is a thread trimming solenoid, and 25 is a thread trimming mechanism.

Claims (1)

[Claims] 1. A storage means for storing sewing data, a driving means for a sewing machine that forms stitches, and a sewing machine that reads out the sewing data stored in the storage means and applies a driving signal to the driving means of the sewing machine to form stitches according to the sewing data. A control means for forming a stitch, an electrically driven thread cutting means which is energized after the stitch is formed by the control means by reading the thread cutting data stored in the storage means, and a count when the thread cutting means starts cutting the thread. The automatic sewing machine is provided with a counting means which issues a signal to the control means to stop energizing the electrically driven thread cutting means in preference to a normal energizing signal to the thread cutting means after a certain count.