JPS6032466B2 - Sewing machine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a needle swinging mechanism for a zigzag stitch sewing machine that is capable of swinging in a direction perpendicular to the cloth feeding direction when the needle is raised,
A sewing machine's feed change depth mechanism that can change its position to control the next cloth feed amount when the needle descends, and therefore when the feed dog sinks, and fabrics that hold sewing pieces such as shirt collars and cuffs. Relating to a sewing machine equipped with an operating mechanism such as a feeding mechanism that drives a holding mechanism intermittently in a predetermined direction when the needle is raised in synchronization with the drive of the sewing machine so as to form a seam line of a predetermined shape on the piece to be sewn, In particular, it relates to a control device for a sewing machine in which the operating mechanisms are controlled by electrically actuated actuators such as step motors and solenoids.

In a conventional zigzag stitch sewing machine, when the horizontal movement of the needle Fujibashi mower is performed from outside the step mo, the time required from the start to the end of the movement is always constant regardless of the rotational speed of the sewing machine. An error occurs in the needle drop position when the sewing machine rotates at a low speed and when the sewing machine rotates at a high speed, resulting in the inability to properly form a predetermined zigzag stitch, and various other inconveniences. That is, as shown in Fig. 3, in the movement A of the needle bar when the sewing machine rotates at low speed, the step motor drive section (from the needle position y) when the needle rises from the fabric (the section above the x-axis) is If a, the driving range b of the motor when the sewing machine rotates at high speed (twice the low speed rotation)
The end of the needle deviates from the point at which the needle descends into the fabric (△b), and as a result, the needle drop is raised before the needle pole swinging mechanism reaches the scheduled swinging position. It becomes impossible to form a zigzag stitch with a width of Disadvantages such as tearing, bending and bending of the needle, etc. occur.

In order to prevent this drawback, it is possible to increase the swinging speed of the needle birch swinging mechanism by increasing the frequency of the pulse input to the step motor and increasing the speed of the step operation of the motor.
The motor may not be able to follow the electrical displacement, causing a step-out, or damping may occur when the rotor completes displacement, causing the needle swinging mechanism to move slightly without completely stopping at the expected swinging position. As a result, the needle drop position varies and beautiful zigzag stitches cannot be formed, so there is a limit to increasing the operating speed of the step motor. In addition, in reverse-stitch sewing machines in which the feed conversion mechanism is controlled by operating a solenoid for a certain period of time to reverse the cloth feed direction, variations in the sewing machine's rotational speed may cause variations in the starting timing of reverse-stitching. For this reason, there is a drawback that it is not always possible to perform stable backstitching.Furthermore, in a feeding mechanism in which the fabric holding mechanism that holds items to be sewn, such as shirt collars and cuffs, is driven step by step from the outside, When the rotation speed of the sewing machine changes from low speed to high speed, the needle drops before the fabric holding mechanism completes feeding, and as with the needle swinging mechanism described above, the fabric continues to be held even after the needle drops. As the mechanism moves to the planned feed position, the piece to be sewn is moved while the needle remains stuck in the piece, which may cause the fabric to be torn by the needle, bent or folded, or the fabric holding mechanism In order to prevent this, the operation speed of the step motor should be increased to speed up each step of the cloth holding mechanism. There is a need,
Therefore, the same drawbacks as above arise.

The present invention provides a sewing machine control device free from the above-mentioned drawbacks by controlling the operating timing of an operating mechanism by advancing or delaying the operating timing of an actuator such as a step motor or a solenoid in accordance with the rotational speed of the sewing machine. The purpose is to

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

In this example, the needle swinging punch of a zigzag stitch sewing machine is implemented in a needle swinging mechanism that is associated with the needle swinging punch in a direction perpendicular to the cloth feeding direction when the needle is raised from the outside of the step motion. . As shown in Fig. 1, a sewing machine and a needle bar swinging village 3 that is swingable about a fixed fulcrum 1 and that supports a needle twill 2 so as to be movable up and down are installed in a jaw part (not shown) of a sewing machine frame. The rotor 5 of a step motor 4 fixedly disposed on the arm is interlocked with the rotor 5 by appropriate link mechanisms 6 and 7, and the step drive of the step motor 4 causes the needle swinging village 3 to move in the cloth feeding direction about the fixed fulcrum 1. (horizontal direction in FIG. 1). As is well known, the needle bar 2 moves up and down in conjunction with the main shaft (not shown) of the sewing machine, and due to its up and down movement, the needle 8 supported at the lower end of the needle bar 2 and the hook (not shown) disposed on the sewing machine bed. ) in cooperation with needle 8
The needle thread held in the hook and the bobbin thread held in the hook are knotted vertically to form a main stitch.

A pulley 9 is fixed to a main shaft (not shown) protruding from the sewing machine frame, and three magnetic sensing elements (Hall elements "magnetoresistive elements etc.") 10, 1 are arranged along the axial direction facing the outer peripheral surface of the pulley 9.
1 and 12 are fixedly arranged on the machine frame, and on the outer peripheral surface of the pulley 9, there is a permanent magnet 13 that faces the sensor 10' when the needle 8 corresponds to the top dead center, and a permanent magnet 13 that faces the sensor 10' when the needle 8 corresponds to the bottom dead center. Sensing body 1
Seven permanent magnet turtles 4 and needles 8 are arranged circumferentially at equal intervals so as to sequentially face the sensor 12 in the rotation angle range in which the permanent magnet tortoise 4 and the needle 8 rise from the bottom dead center to a position slightly above the upper surface of the needle slope. Permanent magnets 15a to 15g are fixedly arranged.
The permanent magnet 13 and the sensing body 8 constitute an upper layer detection means, and when the sensing body 10 senses magnetism, it generates an H level upper layer signal. When the sensor 11 senses magnetism, it generates an H level lower layer signal.
Further, the amount of permanent magnets 5a to 15g and the sensing body tatami 2 constitute a timing detecting means (second detecting means), and the sensing body 12
When sensing the magnetism of each of the permanent magnets 15a to 15g, it sequentially generates seven H-level timing pulses. It is self-evident that these detected signals have pulses that are inversely proportional to the sewing machine drive speed.

Next, the electric circuit shown in FIG. 4 will be explained. G is an AND or NAND gate, and 1 is an invert gate. The OS is a pulse oscillator that generates intermittent pulses with a constant period while the lower layer signal is generated.

CT and CT2 are counter circuits, and one counter circuit CT and # catch and count the falling edge of the intermittent pulse generated by the pulse oscillator OS, and the other counter circuit C
T2 captures and counts the falling edge of the timing pulse, and both counter circuits CT, CT2 are cleared by the above position signal and "PC is exclusive OR, ~OR3".
It is a coincidence circuit composed of both counter circuits CT
, , When the outputs of CT2 match, each output is set to L level and a match signal of H level is generated from NOR gate G3.

These two counter circuits CT, , CT2 and the coincidence circuit PC
A comparison circuit is formed by the gate G3 and the gate G3. F is the well-known J-K type flip-flop, and the AND gate G
4 is used as a clock signal, the Q terminal is set to L output, and cleared by the rise of the lower layer signal (inverted by inverter 1), and the Q terminal is set to day output.

The NAND gate G2 acts to close the AND gate G by providing an L output when the counter circuit CT counts a predetermined number (seven) of pulses.

AND gate G5 is the control circuit for stepping motor 4 (
(not shown) and use the output on that day as the activation signal.
The present invention has the above-mentioned configuration, and its operation will be explained next with reference to the time chart shown in FIG.

When the needle 8 descends to the bottom dead center due to the rotation of the main shaft of the sewing machine, a lower layer signal is generated from the sensor 11, and in relation to this, the flip-flop F is cleared and the Q terminal becomes the daily output, and the oscillator OS An intermittent pulse is generated and becomes a clock input to the counter circuit CT through the gate G. When the sewing machine is driven at high speed, the pulse duration of the lower layer signal is short, so the number of intermittent pulses of the oscillator OS is reduced, and when the sewing machine is driven at low speed, the duration of the pulse of the lower layer signal is shorter. Since it is long, the number of intermittent pulses is large. When the sewing machine is driven at high speed and, for example, two intermittent pulses are generated, the counter circuit CT counts these two intermittent pulses and outputs "LHL", which becomes one input of the coincidence circuit PC.

When the needle starts to rise after passing the bottom dead center, the permanent magnets 15a to 15g sequentially pass through the sensor 12 and a timing pulse is generated, and when the second timing pulse 15b is generated, the counter circuit CT2 is activated. The output becomes "LHL", which becomes the other input of the matching circuit PC, and matches the input from T to the counter circuit, so each output of the matching circuit PC becomes L level, and gate G3 becomes H level matching. Generate a signal. Next, the third timing pulse 15c
When this occurs, the gate G5 becomes a daily output and becomes an operating signal to the control circuit of the stepping motor, and when the gate timing pulse falls and becomes an L output, the Q terminal of the flip-flop F becomes an L level. Also, when the sewing machine is driven at low speed and, for example, four pulses are generated from the oscillator OS, the count circuit CT counts these four intermittent pulses and makes the output "HLL'', and outputs it to one input of the matching circuit PC. becomes.

When the fourth timing pulse 15d occurs while the hand is rising, the counter circuit C is input as the other input of the coincidence circuit PC.
“HLL” of T2 is input, and each output of the matching circuit PC is set to L.
The gate G3 generates an H level coincidence signal. When the next fifth timing pulse is generated, the gate G5 generates an activation signal and sets the Q terminal of the flip-flop F to the L level in the same manner as described above. As is clear from this, the number of intermittent pulses counted by the counter circuit CT is inversely proportional to the sewing machine driving speed, and therefore the number of intermittent pulses counted by the counter circuit CT
The timing at which L counts the same number of timing pulses and generates a coincidence signal is inversely proportional to the sewing machine driving speed.

As described above, according to the present invention, in a sewing machine having an actuation mechanism that moves to actuate an electric actuator for a certain period of time when the needle rises or falls from the fabric to be sewn, the sewing machine has a pulse period that is inversely proportional to the sewing machine drive speed. The driving speed of the sewing machine is determined by activating the operating mechanism in relation to the number of pulses between the comparison signal generated during the generation of the detection signal and the timing signal generated thereafter. Even if the speed changes, the operation signal can always be generated at a time appropriate for the speed, so the stepping motor can be operated reliably. case,
This prevents the end of motor drive when the sewing machine is rotating at high speed from being delayed until the time when the needle descends onto the fabric.
Whether the sewing machine is running at low speed or high speed, the needle can be dropped after the needle oscillation mechanism reaches the predetermined oscillation position, making it possible to always produce zigzag stitches with the appropriate width. In addition to being able to prevent the needle from moving laterally while stuck in the fabric, the fabric is not torn by the needle or bent and bent, resulting in excellent safety effects. is obtained, and
Since there is no need to increase the oscillation speed on the side of the needle oscillation machine more than necessary, there is no need to increase the frequency of the pulses input to the step motor more than necessary. It is possible to prevent damping from occurring during completion, and as a result, a stable zigzag stitch can be formed at all times, and there is no variation in the layer at the needle drop point, allowing for beautiful zigzag stitches to be formed at all times. The effect of this can be obtained.

In the above example, the needle oscillation mechanism of the zigzag stitch sewing machine was oscillated by a step motor, but the fabric feeding direction could be reversed by operating the tosolenoid for a certain period of time like in a reverse stitch sewing machine. A similar effect can be obtained by controlling the feed conversion mechanism so as to change the start time of reverse stitching, that is, the activation time of the solenoid, in response to changes in the rotational speed of the sewing machine. In the feed mechanism of a sewing machine, the cloth holding mechanism that holds pieces to be sewn such as collars and cuffs is intermittently driven by the step drive of a step motor. A similar effect can be obtained by changing the opening timing of the drive.

[Brief explanation of drawings]

The turtle figure is a front view of the needle swinging mechanism of a zigzag stitch sewing machine that is driven in steps by a step motor, Figure 2 is a perspective view of the sewing machine pulley, and Figure 3 is a needle at low and high speed rotations of the sewing machine. FIG. 4 is an electric circuit diagram of this embodiment, and FIG. 5 is a time chart. Z Zusai 3 Zuzu Rokuzu Ritazu ``Ichiki

Claims (1)

[Claims] 1. In a sewing machine that has an operating mechanism that is linked to the operation of an electric actuator for a certain period of time when the needle rises or falls from the fabric being sewn, the speed that is a first detection means for generating a detection signal with a pulse width; a second detection means for generating a timing signal of a constant period in synchronization with the driving of the sewing machine after generation of the detection signal in relation to the rotation of the sewing machine main shaft; and generation of the detection signal. an oscillator that generates a comparison signal of a constant period within its generation period, a comparison circuit that compares the number of occurrences of the comparison signal and the timing signal and generates a coincidence signal when the numbers match; A control device for a sewing machine, comprising: a control circuit that operates an actuator in relation to an occurrence.