JP2567955B2 - Sewing machine drive controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine drive control device, and more particularly to a malfunction in a sewing machine control device that detects the depression of a foot pedal and controls the electric drive of a sewing machine drive shaft. Regarding prevention.

[Conventional technology]

In an electrically driven industrial sewing machine, an electric drive control command for a sewing machine drive shaft is given by operating a foot pedal. Generally, by stepping on the foot pedal in the forward direction (front stepping), the sewing operation is performed at a speed according to the stepped amount, and by pressing in the rear direction (reverse stepping), the thread trimming operation is performed. And the work clamp foot lifting operation.

To this end, the sewing machine drive control device is provided with a detection device including a front step detection switch, a reverse step detection switch for detecting the stepping direction of the foot pedal, and a step amount detector for detecting the step amount. This detection device is configured to rotate the switch operating lever, which is maintained at the neutral position by the return spring, in conjunction with the depression of the foot pedal. The inertia of the switch operating lever causes the return spring to vibrate, and the switch operating lever also vibrates, so that the two detection switches generate a stepping detection signal in response to this. Therefore, the control circuit executes the sewing machine drive control against the operator's intention. For example, a predetermined number of stitches is patterned and stored, the next stitch number is sequentially read, and the stitching operation is automatically performed to perform stitch number control. When the stitching operation for the number of stitches is completed and the sewing direction is changed for the next sewing operation, the foot operation pedal is released and the switch operation lever vibrates, causing the reverse operation detection switch to respond and reverse operation. When the detection signal is generated, the thread trimming operation and the presser foot lifting operation are performed and the sewing operation ends, and when the front stepping detection switch responds again and the front stepping detection signal is generated, the next sewing operation is performed. There is a problem that will start. In particular, if the next sewing operation starts in an unplanned direction, even if the next sewing operation is removed, the stitches will remain on the material and the quality of the sewn product will be degraded.

[Problems to be Solved by the Invention]

As described above, in the conventional sewing machine drive control device, the two detection switches each generate a detection signal in response to the vibration of the switch operating lever when the foot pedal is suddenly released from the depressed state, and the control circuit generates the detection signals. However, there is a problem in that the sewing machine drive control is executed (malfunction) against the operator's intention in response to the detection signal.

Therefore, an object of the present invention is to prevent malfunction due to a depression detection signal (erroneous signal) generated from the detection switch in response to vibration of the switch operating lever when the foot pedal is rapidly released from the depressed state. is there.

[Means for Solving the Problems] The present invention, in order to achieve this object, a foot pedal,
A front stepping detection switch that detects that the foot pedal is stepped forward, a reverse step detection switch that detects that the foot pedal is stepped backward, and a stepping pedal that is stepped forward Depression amount detector that outputs a speed command signal of a magnitude corresponding to the amount, and drive of the sewing machine drive shaft in response to the front step detection signal from the front step detection switch and the speed command signal from the step amount detector. A sewing machine drive control device including a motor control circuit for controlling the thread cutting solenoid and the presser foot solenoid in response to a reverse depression detection signal from the reverse depression detection switch. In response to the fact that the front stepping detection signal output from the stepping detection switch has changed from the state of stepping on the foot pedal to the state of being released, Is provided with a retriggerable timer that outputs a response prohibition signal for a predetermined time after the retriggerable timer, the electric motor control circuit, and the solenoid control circuit are configured using a microcomputer, and the response prohibition signal is output. During this period, the electric motor control circuit and the solenoid control circuit respond to changes in the front depression detection signal output from the front depression detection switch and the reverse depression detection signal output from the reverse depression detection switch. When the response inhibition signal is not output, the drive of the sewing machine drive shaft is controlled in response to the front stepping detection signal, and the thread trimming solenoid and the presser foot solenoid are driven in response to the reverse stepping detection signal. It is characterized in that it is configured to control.

[Action]

When the front depression detection signal changes from the state where the foot pedal is depressed to the state where it is released, the response prohibition signal is output for a predetermined time after that, and the motor control circuit and solenoid control circuit Since it does not respond to changes in the foot depression detection signal or reverse foot depression detection signal, sewing operation, thread trimming operation, cloth The work clamp operation (malfunction) is prevented.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is an external view of an electrically driven industrial sewing machine according to the present invention. The sewing machine main body 1 is mounted on the upper side of the table 2 and driven by an electric motor 3 mounted on the lower side of the table 2. A rotation speed generator 5 and a needle position detector 6 are further attached to the outside of the sewing machine pulley 4 attached to the end of the drive shaft of the sewing machine. A belt 8 penetrating the table 2 is wound around the sewing machine pulley 4 and an electric motor pulley 7 attached to the output shaft end of the electric motor 3 to connect the sewing machine body 1 and the electric motor 3. When the electric motor 3 is an indirectly driven clutch motor, the rotor of the electric motor 3 is continuously rotating, and the rotation of the output shaft is controlled by the clutch plate and the brake plate. The rotation of the rotor of the electric motor 3 is controlled. A controller 9 for controlling the electric motor is attached to the lower side of the electric motor 3, and a detection device provided in the controller 9 is connected to a foot pedal 11 via a connecting rod 10.

FIG. 3 is a side view of the switch operating lever portion of the detection device. The connecting rod 10 is connected to the end of a switch operating lever 12b attached to the shaft end of an operating shaft 12a for operating the front depression detecting switch, the reverse depression detecting switch, and the depression amount detector provided in the controller 9. . The switch operation lever
12b is urged in the clockwise direction by the tension of the front stepping return spring 12c, which is a tension spring, and is supported in the neutral position by the extension force of the reverse stepping return spring 12d in the compressed state. FIG. 3 illustrates this neutral state. In this state, both the front depression detection switch and the reverse depression detection switch in the controller 9 are in the off state, and the speed command signal output from the depression amount detector is in the lowest state.

When the foot pedal 11 is stepped forward, the switch operating lever 12b rotates counterclockwise to turn on the front step detection switch and output a front step detection signal (becomes a low level) and detect the stepped amount. The instrument outputs a speed command signal having a magnitude corresponding to the amount of depression.

Then, when the foot pedal 11 is released, the switch operating lever 12b is rotated clockwise by the tension of the front stepping return spring 12c and is received by the reverse stepping return spring 12d and stopped at the neutral position. As a result, the front stepping detection signal disappears (becomes a high level).

On the contrary, when the foot pedal 11 is depressed in the reverse direction, the switch operation lever 12b rotates clockwise against the extension force of the reverse depression return spring 12d, and the reverse depression detection switch is turned on to output the reverse depression detection signal. Yes (becomes the Loule level).

When the foot pedal 11 is released, the switch operating lever 12b rotates counterclockwise by the extension force of the reverse step return spring 12d and stops at the neutral position. As a result, the reverse pedal detection signal disappears (becomes a high level).

Although it is desirable for the detection device to operate in this way,
Actually, when the foot pedal is suddenly released from the front stepping state, the switch operating lever 12b is suddenly returned by the tension of the front stepping return spring 12c and collides with the reverse stepping return spring 12d. While rotating 12d while compressing 12d, it bounces and vibrates. As a result, the reverse depression detection switch and the front depression detection switch are alternately turned on and off repeatedly to generate a depression detection signal (erroneous signal). FIG. 4 shows the waveform of the depression detection signal at this time.

The present invention prevents a malfunction due to such a false detection signal, and a control circuit provided in the controller 9 for that purpose is shown in FIG.

In FIG. 1, 9a is a front step detection switch that outputs a front step detection signal in response to the rotation of the operation shaft 12a due to the front step of the foot pedal 11, and 9b is the step pedal 11
The reverse depression detection switch that outputs a reverse depression detection signal in response to the rotation of the operation shaft 12a due to the reverse depression, 9c is the depression amount that outputs a speed command signal of a size corresponding to the rotation amount of the operation shaft 12a. A detector 9d is an electric motor control circuit for controlling the rotational output of the electric motor 3 in response to the front depression detection signal (change from high level to low level) and a speed command signal, 9e.
Is a solenoid control circuit which drives the thread trimming solenoid 13 and the work clamp solenoid 14 in response to the reverse depression detection signal (change from high level to low level), and 9f is the front depression detection signal that the foot pedal 11 is depressed. In response to the state that the switch operating lever 12b has been released from the state and returned to the neutral position (changed from the low level to the high level), the response prohibition signal is output for a predetermined time thereafter. It is a retriggerable timer. And
The electric motor control circuit 9d and the solenoid control circuit 9e are configured so as not to respond to the front depression detection signal and the reverse depression detection signal while the response inhibition signal is output.
As shown by T ₁ in FIG. 4, the predetermined time length of the response prohibiting signal output from the retriggerable timer 9f causes the switch operating lever 12b to vibrate and the front stepping detection switch 9a.
The time is set to a little longer than the time it turns on after turning on. The retriggerable timer 9f is used to prevent malfunction even when multiple false detection signals are generated.

According to the control circuit configured as described above, even if an erroneous detection signal is generated from the front depression detection switch 9a and the reverse depression detection switch 9b even by the vibration of the switch operation lever 12b,
Since the erroneous detection signal is ignored, it does not malfunction.

The electric motor control circuit 9d, the solenoid control circuit 9e, and the retriggerable timer 9f are configured by using a microcomputer, and the malfunction prevention control function is realized by the signal processing function of the microcomputer.

FIG. 5 is a signal processing flow chart by the microcomputer when the malfunction prevention control function is realized by the microcomputer.

 Process 101 is a process of inputting a front stepping detection signal.

In process 102, it is checked whether or not the input front depression detection signal has changed from low level to high level. If it has changed, the process proceeds to process 103, and if it has not changed, the process proceeds to process 104.

In step 103, the retriggerable timer checks whether or not it has finished counting the predetermined time, and if so, it is determined that the switch operating lever 12b has been returned to the neutral position for the first time, and the motor stop control step 105 is executed. Process after running 1
At 06, the retriggerable timer is triggered to set the response disabled state, and the process returns to the front depression detection signal input processing 101. In the automatic sewing operation mode, the motor stop control process 105 is omitted. If the retriggerable timer has not finished counting the predetermined time in the check in step 103, the switch operating lever
It is determined that the signal is an erroneous detection signal due to the vibration of 12b, the process proceeds to step 106, where the retriggerable timer is retriggered, and then the process returns to the front stepping detection signal input process 101.

In process 104, it is checked whether or not the input front stepping detection signal is at high level. If it is high level, the process proceeds to process 107, and if it is low level, the process proceeds to process 108.

In process 107, it is checked whether or not the retriggerable timer has finished counting the predetermined time, and if not completed, the process returns to the front depression detection signal input process 101. If it has been completed, the process proceeds to reverse pedal detection signal input processing 109.

After the reverse stepping detection signal is input in the reverse stepping detection signal input processing 109, it is checked in step 110 whether the reverse stepping detection signal has changed from the high level to the low level. If not, the front stepping detection signal is detected. The processing returns to the input processing 101, and if there is a change, the processing moves to processing 111.

Process 111 is a thread cutting solenoid and cloth pressing solenoid operation control process, which executes a process of energizing each solenoid at a predetermined timing and returns to the front step signal input process 101.

In the process 108, it is checked whether or not the retriggerable timer has finished counting the predetermined time. If it is not completed, it means that it is a reaction prohibition period, and therefore, the process returns to the front stepping detection signal input process 101, and if it is completed, the process proceeds to process 112.

The process 112 is a motor rotation control process, and the motor 3 is controlled so that the rotation output corresponding to the magnitude of the speed command signal is obtained.
Performing the power supply amount control to the front depression detection signal input processing
Return to 101.

By such signal processing by the micro computer, it is possible to prevent the erroneous operation due to the erroneous detection signal described above.

〔The invention's effect〕

As described above, according to the present invention, in response to the fact that the front depression detection signal is in the state indicating that the depression pedal is released, the response prohibition signal is output for a predetermined time thereafter. Since a triggerable timer is provided and the electric motor control circuit and solenoid control circuit are configured not to respond to changes in the front depression detection signal and the reverse depression detection signal while the response inhibition signal is being output, It is possible to prevent the sewing operation, the thread trimming operation, and the presser foot operation (erroneous operation) due to the front stepping detection signal and the reverse stepping detection signal (erroneous signal) output by the vibration of the switch operating lever.

[Brief description of drawings]

1 shows a control circuit diagram, FIG. 2 is an external view of an electrically driven industrial sewing machine, FIG. 3 is a side view of a switch operating lever portion of a detection device, and FIG. FIG. 4 is a waveform diagram of the depression detection signal, and FIG. 5 is a signal processing flow chart of the microcomputer for realizing the malfunction prevention control function. 1 ... Sewing machine main body, 3 ... electric motor, 9 ... controller, 9a ...
… Front pedal detection switch, 9b …… Reverse pedal detection switch, 9c
...... Stepping amount detector, 9d ...... Motor control circuit, 9e ...... Solenoid control circuit, 9f ...... Retriggerable timer, 11 ......
Foot pedal, 12b ... Switch operating lever, 13 ... Thread trimming solenoid, 14 ... Cloth pressing solenoid.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayuki Kanari 1-1-1, Higashitaga-cho, Hitachi-shi, Ibaraki Inside the Taga factory, Hitachi, Ltd. (56) Reference JP-A-57-206487 (JP, A) Kai 64-56094 (JP, A) JP 61-20590 (JP, A) JP 59-13876 (JP, B2) JP 63-49265 (JP, Y2)

Claims (1)

(57) [Claims] 1. A foot pedal, a front foot detection switch for detecting that the foot pedal is stepped forward, and a reverse foot detection switch for detecting that the foot pedal is stepped rearward. A stepping amount detector that outputs a speed command signal having a magnitude corresponding to the stepping amount of the foot pedal that is stepped forward, a front stepping detection signal from the front stepping detection switch, and a speed command from the stepping amount detector. A motor control circuit that controls the drive of the sewing machine drive shaft in response to a signal, and a solenoid control circuit that controls the drive of the thread trimming solenoid and the presser foot solenoid in response to the reverse depression detection signal from the reverse depression detection switch. In the sewing machine drive control device provided with, the state that the front depression detection signal output from the front depression detection switch is released from the state in which the foot pedal is depressed. A retriggerable timer that outputs a response prohibition signal for a predetermined period of time in response to the fact that
The retriggerable timer, the electric motor control circuit, and the solenoid control circuit are configured by using a microcomputer, and the electric motor control circuit and the solenoid control circuit are operated while the response prohibiting signal is being output. When the forward depression detection signal output from the front depression detection signal and the reverse depression detection signal output from the reverse depression detection switch are not responded to, and the response prohibition signal is not output, the front depression detection signal is responded to. The sewing machine drive control device is configured to control the drive of the sewing machine drive shaft and to control the drive of the thread trimming solenoid and the cloth pressing solenoid in response to the reverse depression detection signal.