JPH04361787A - Position control device for industrial sewing machine - Google Patents

Abstract

PURPOSE:To improve the precision of an industrial sewing machine to stop at the fixed position by performing the delay control inversely proportional to the rotating speed while the needle position when a front depression switch is turned off is used as an origin. CONSTITUTION:When a front depression switch 6 is turned on, a speed control device 1 reads the set speed from a speed setter 7 and controls the sewing machine rotating speed from an encoder 3 and a needle position detector 4 to be equal to the set value. The stop time is set to T when the deceleration process from the first lower position signal is performed after the front depression switch 6 is turned off while a sewing machine is operated at the rotating speed Na. When the rotating speed is Nb, the deceleration process is performed after pulse signals from the encoder 3 are counted by Pb shown in the figure inversely proportional to Nb from the first lower position. When the rotating speed is No lower than Nb, the deceleration process is performed after pulse signals are counted by Pc inversely proportional to Nc. The sewing machine can be stopped at the same stop time T regardless of when the front depression switch 6 is turned off or what is the rotating speed.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a position control device for an industrial sewing machine, which suppresses variations in operating time when stopped in deceleration control after turning off the front pedal switch. This invention relates to a position control device.

0002

[Prior Art] As a position control method for industrial sewing machines,
When the front pedal switch is turned off, a low-speed rotation command that can be stopped is output to start deceleration, and when the lower position or upper position signal is detected, the sewing machine rotation speed changes to the rotation speed N that can be stopped.
If the sewing machine has reached o, a stop command is output, and after a certain period of time, if the sewing machine is within the lower position width, it is determined that the sewing machine has stopped.

[0003] A prior art related to a method of controlling the position of a sewing machine is described in, for example, Japanese Patent Application No. 189260/1982.

0004

[Problems to be Solved by the Invention] However, conventional position control methods for industrial sewing machines execute deceleration processing starting from the point at which the front switch is turned off until the rotation speed reaches a point at which it can be stopped. When the lower position signal from the device rises, if the rotation speed has reached the point where it can be stopped, the stop processing is performed.

[0005] Therefore, when the number of revolutions at which it can be stopped is reached after the down position signal from the needle position detector has passed, it will continue to rotate until the next down position signal comes, so it takes time equivalent to one revolution. It turns out. Furthermore, this time becomes longer as the rotation speed that can be stopped is set lower.

Furthermore, when deceleration is started from the time when the front pedal switch is turned off, the rotational angle position is different at the time when the front pedal switch is turned off, so the operating time at the time of stopping varies within the time equivalent to one revolution. I will do it.

[0007] Therefore, there has been a problem in that the efficiency during sewing work is reduced and the time required for stopping changes for each sewing operation, which disrupts the sewing rhythm and prevents the sewing work from being carried out smoothly.

SUMMARY OF THE INVENTION An object of the present invention is to provide a position control device for an industrial sewing machine that improves the accuracy of stopping the industrial sewing machine at a fixed position.

[0009]

[Means for Solving the Problems] The object is to provide a sewing machine body, a motor for driving the sewing machine, a needle position detector for detecting the position of the needle of the sewing machine and generating an upper position or lower position signal, and a pedal. a front pedal switch that outputs a stop command signal at a predetermined position; a means for providing an encoder on the motor and measuring the rotation of the motor based on the number of pulses from the encoder; and a signal from the front switch. In an industrial sewing machine comprising a position control device that controls the drive of This is achieved by providing means for counting the number of encoder pulses inversely proportional to the number of rotations and delaying the timing at which deceleration starts.

0010

[Operation] As mentioned above, the position control device of an industrial sewing machine detects the sewing machine rotational speed from the encoder at the time when the needle position detector first rises to the upper or lower position after the front switch is turned off. It is calculated using a pulse signal, and a value corresponding to the inverse proportion of the rotation speed is set, and then the number of encoder pulses is counted, and the start of deceleration is delayed until the number becomes equal to the set value.

[0011]

[Embodiment] The present invention will be described below based on an embodiment of the drawings. FIG. 1 is a block diagram showing the overall configuration of a position control device according to the present invention, and FIG. 2 is a block diagram showing the position control device shown in FIG. 1. FIG. 3 is a timing chart of various signals generated in the device, and is an operation flowchart of the position control device shown in FIG. 1.

In FIG. 1 showing the overall configuration of the position control device, 1 is a speed control device including a microcomputer, a comparator, a control section, etc., 2 is a sewing machine driving motor,
3 is an encoder, 4 is a needle position detector installed on a pulley portion 5 of the sewing machine body and detects the needle position of the sewing machine, 6 is a front pedal switch, 7 is a speed setting device, and 8 is a rotation speed measuring device.

In the above configuration, when the sewing worker turns on the front pedal switch 6, the speed control device 1 controls the speed setting device 7.
The set speed is read from , and the sewing machine rotation speed from the encoder 3 and needle position detector 4 is controlled so as to be equal to the set value.

Next, when the front pedal switch 6 is turned off, deceleration processing is performed from that point on as shown in FIG. 2(a).
If the sewing machine reaches a rotational speed N at which it can be stopped at the time of the lower position signal obtained from the needle position detector 4, a stopping process is performed to stop the sewing machine.

The stop position at this time is the same as when the sewing machine rotational speed is Na, for example, when the sewing machine rotational speed is high when the front pedal switch 6 is off (time S0 in the figure) as shown in FIG. 2(a). When Nb, when the sewing machine rotation speed is Na,
Since the rotation speed N that can be stopped is reached when the lower position rises, the stop processing is performed immediately. However, in the case of Nb, since the rotation speed N that can be stopped is reached after the lower position rises, it takes Tb time to stop. It will take a while.

Further, if the front pedal switch 6 is turned off at time S1, the stop time will be Tc even if the rotational speed at this time is equal to the sewing machine rotational speed Na.

In this way, when the front pedal switch 6 is turned off and the vehicle is decelerated and stopped at the same time, it is inevitable that the stopping time will vary.

However, when the sewing machine is rotating at the rotational speed Na as shown in FIG. When the stop time is T, when the sewing machine rotation speed is Nb, the graphic Pb is inversely proportional to the sewing machine rotation speed Nb from the initial lower position, and when the speed Nc is lower than Nb, the graphical representation is similarly inversely proportional to the Nc. Encoder 3 for Pc
If the deceleration process is performed after counting the number of pulse signals from the It can be stopped at T and is controlled in that way.

As described above, this embodiment uses a microcomputer for position control, and the above control will now be explained based on the flowchart shown in FIG.

Now, when the front pedal switch 6 is turned on, the microcomputer sets the flag to φ and executes speed control.

Next, when the front pedal switch 6 is turned off, if the flag is φ and is not in the lower position, the first lower position after the front pedal switch 6 is turned off has not yet been detected, so no deceleration processing is performed and the speed is Keep control running.

When the flag is φ and the lower position is detected, the flag is set to 1, the rotational speed at this time is measured, and the number of pulses P (Pb, Pc in FIG. 2(b)) for delaying is calculated. Then, the calculated value of P is set in the counter.

At this time, if P is φ, the deceleration process is executed immediately, but if P is greater than 0, the deceleration process is not performed and when the above routine of FIG. 3 is entered again,
Since the flag is 1, we do not judge the bottom position or calculate the delay time, but judge whether the counter value has reached 0 and set it to 0.
If so, deceleration processing is performed, and the timing of executing the deceleration processing is delayed by the value of P.

[0024]

Effects of the Invention The present invention is as described above, and as is clear from the explanation of the illustrated embodiments, the present invention provides an industrial sewing machine that improves the accuracy of fixed position stopping in an industrial sewing machine. This invention can provide a position control device for a sewing machine, and can be said to be an invention with excellent practical effects.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of a position control device according to the present invention.

FIG. 2 is a timing chart of various signals generated in the position control device shown in FIG. 1;

FIG. 3 is an operation flowchart of the position control device shown in FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1...Speed control device, 2...Sewing machine drive motor, 3...Encoder, 4...Needle position detector, 5...Pulley section, 6...Front pedal switch, 7...Speed setting device, 8...Rotation speed measuring device.

Claims (1)

[Claims] 1. A sewing machine body, a motor that drives the sewing machine, a needle position detector that detects the position of the needle of the sewing machine and generates an upper position or lower position signal, and a needle position detector that generates a stop command when a pedal is at a specified position. a front pedal switch that outputs a signal; and means for providing an encoder on the motor and measuring the rotation of the motor based on the number of pulses from the encoder;
In an industrial sewing machine comprising a position control device configured to drive and stop the motor in a fixed position based on a signal from the front pedal switch, the motor is moved to the first lower position or the first lower position after the front switch is turned off. A position control device for an industrial sewing machine, characterized in that the number of pulses of an encoder is controlled to be delayed by counting the number of pulses of an encoder in inverse proportion to the number of revolutions at the starting point, starting from the upper position.