JPH03205098A - Safety protecting device for industrial sewing machine - Google Patents

Abstract

PURPOSE:To prevent any breakage of a sewing machine or any danger applied on a sewing worker by stopping a motor after judging that the revolution direction of the motor is abnormal, when the motor revolves in the reverse direction to the revolution direction instruction supplied from a microcomputer. CONSTITUTION:When a stepping-on switch is turned ON, driving signals are outputted to a motor 17 from a driving circuit 14 and a drive controller 15, and the motor 17 starts revolution. At this time, if the motor 17 normally revolves according to the normal.reverse revolution instruction supplied from the drive controller 15, a safety protecting device 16 does not operate. While, when the motor revolves in the reverse direction for a normal revolution instruction supplied from a microcomputer, an encoder signal supplied from the motor forms the wave shape shown on the Fig.4, and the microcomputer judges from the encoder signal that the motor is reversely revolved, and the safety protecting device operates to stop the motor. Further, even if a reverse revolution instruction is outputted from the microcomputer, if the revolution direction of the motor is reverse to the revolution instruction, the safety protecting device operates to stop the motor.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a motor drive safety protection device, and when the motor rotates in the opposite direction in response to a rotation command from a microcomputer, the motor rotation direction is determined to be abnormal. This is a motor drive safety protection device that stops the motor drive.

[Conventional technology]

As a conventional safety protection device, for example, Japanese Patent Application Laid-Open No. 59-503
It is disclosed in No. 55. However, this device does not have a safety protection function in the event that the motor rotates in the opposite direction in response to the forward and reverse rotation commands, so even if the motor rotates in the opposite direction to the rotation direction command from the microcomputer, it cannot be determined that there is an abnormality. Therefore, the motor continues to rotate. This causes damage to the sewing machine and danger to the sewing worker.

[Problem to be solved by the invention]

In the conventional technology, only the motor is controlled by a needle position detector installed in the sewing machine body that generates a needle position signal corresponding to the vertical position of the needle, and a speed detector installed in the sewing machine body to detect the sewing machine rotation speed. Was. For this reason, if
If the microcomputer outputs a signal for forward rotation, even if the motor rotates in the opposite direction, this rotational abnormality could not be detected. Because the abnormal rotation cannot be detected, the motor continues to rotate in the opposite direction, potentially damaging the sewing machine or endangering the sewing worker.

The purpose of the present invention is to constantly monitor the rotational direction of the motor, and if the motor rotates in the opposite direction in response to forward/reverse rotation commands from a microcomputer, it is possible to stop the motor as an abnormal rotation. . This results in
This is a safety protection device that can completely eliminate damage to the sewing machine and danger to sewing workers.

[Means to solve the problem]

The control structure of the industrial sewing machine according to the present invention includes a sewing machine main body and a needle position detector installed in the sewing machine main body that generates a needle position signal corresponding to the vertical position of a needle that is moved up and down in conjunction with rotation. a sewing machine drive motor operatively connected to the drive shaft of the sewing machine; an encoder that generates a signal proportional to the rotational speed of the motor; In a safety protection device for industrial sewing machines that consists of a speed control device to control the speed of the motor, the motor checks whether the motor rotation direction is correct in response to forward/reverse rotation commands from the microcomputer to the motor. This is a safety protection device that detects by feeding back the encoder signal from the

[Effect]

In the present invention, when the motor rotates in the opposite direction to the rotation command from the microcomputer in response to a forward/reverse rotation command from the microcomputer, the encoder signal from the motor becomes a reverse rotation signal instead of a forward rotation signal. .

In this case, the motor rotation direction is abnormal, the safety protection device is activated, and the motor is stopped. This makes it possible to completely prevent rotation in a direction opposite to the rotation command from the microcomputer.

〔Example〕

Examples related to the present invention will be described with reference to each episode.

FIG. 1 shows a schematic structure of a general industrial sewing machine, in which a sewing machine main body 1 is mounted on a table 2, and a motor 3 is mounted below. Furthermore, a detector 6 for detecting the position of the sewing machine needle is attached. Next, a belt 8 is applied to the sewing machine driving pulley 4 and the motor pulley 7 attached to the shaft of the motor 3, a controller 9 is attached to control the operation of the motor 3 and the sewing machine body 1, and a sewing command is issued using the foot switch pedal 10. is provided to the controller 9.

When the foot switch pedal 10 is stepped forward, a drive signal is output from the controller 9 to the motor 3, and the motor 3 starts rotating.

To explain with the schematic diagram of FIG. 2, when the foot switch is turned on, a drive signal is output from the drive circuit 14 and the drive control device 15 to the motor 17, and the motor 17 starts rotating. At this time, if the motor 17 rotates correctly in response to the forward and reverse rotation commands from the drive control device 15,
The encoder signal shown in FIG. 3 is obtained, and the safety protection device 16 does not work.

However, if the motor rotates in the opposite direction in response to the forward rotation command from the microcomputer, the encoder signal from the motor will have the waveform shown in Figure 4, so the microcomputer will indicate that the motor is rotating in the opposite direction based on the encoder signal. The safety protection device operates and stops the motor.

Further, even when a reverse rotation command is output from the microcomputer, if the rotation direction of the motor is reverse to the rotation command, the safety protection device is activated and the motor stops.

〔Effect of the invention〕

According to the present invention, in the safety protection device for an industrial sewing machine, when the motor rotates in the reverse direction, the motor can be stopped, which has the effect of improving safety and reliability.

[Brief explanation of the drawings] Figure 1 is a perspective view showing the general configuration of an industrial sewing machine, Figure 2 is a diagram showing a simple safety protection device, and Figure 3 is a diagram showing the forward rotation (C
Figure 4 shows the encoder signal from the motor of CV).
The figure shows an encoder signal from the motor during reverse rotation (CW). ■... Sewing machine body, 3... Motor, 9... Controller, 10... Foot switch pedal, 16... Safety protection device. 7゛, 2 drawings] Cor φ signal when rotating forward [(W) body] Cor “l gohi”

Claims (1)

[Claims] 1. A sewing machine main body, a needle position detector installed in the sewing machine main body that generates a needle position signal corresponding to the vertical position of the needle that moves up and down in conjunction with rotation, and a needle position detector installed on the sewing machine main body that generates a needle position signal corresponding to the vertical position of the needle that moves up and down in conjunction with rotation, and a sewing machine driving motor connected to the motor; an encoder that generates a signal proportional to the rotational speed of the motor; and a speed control device connected to the motor and controlling the speed of the motor based on the depression of a foot pedal. An industrial sewing machine characterized in that, in an operation safety protection device for an industrial sewing machine, if the motor rotates in a direction opposite to a rotation direction command from a microcomputer, the rotation direction of the motor is determined to be abnormal and the motor is stopped. Safety protection device.