JPS5941753B2 - Sewing machine single stitch control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a sewing machine equipped with a single stitch mechanism, and its purpose is to enable automatic needle stitching in addition to normal stitching and normal needle stitching. - Reduction of noise during needle sewing, Normal - Prevention of re-rotation due to erroneous operation when stopping the needle line,
The purpose of this invention is to enable adjustment of the repetition cycle of automatic needle stitching.

That is, the present invention has a mechanism in which the mechanism and electric circuit are set to one-stitch sewing by selecting the operation knob for one-stitch sewing, and when the controller is depressed, the sewing machine rotates once and stops at a predetermined stop phase. As a stopping means, a method of mechanically preventing rotation is usually used.

In addition, after stopping, it is possible to have either a mechanism in which the drive unit including the motor remains locked while the controller remains depressed, or a mechanism in which it is released by a clutch and rotates freely, and then when the controller is released, the driving force is restored. is released, and thereby the stop mechanism can also release its rotation blocking state.

The present invention adds a new control device to a sewing machine equipped with a single-stitch sewing mechanism as described above, and automatically controls the operation knob.
You can select needle stitching, and if you select automatic needle stitching,
The object of the present invention is to provide a device that automatically repeats the above-mentioned needle stitching operation at a constant cycle while the controller is kept depressed.

The features of the present invention are as follows: (1) In the case of normal needle stitching,
Immediately after the motor stops, the motor current is cut off and this state is maintained, so even if the controller is kept depressed, the motor does not generate any humming or rotational noise.

In addition, when the sewing machine is manually moved after it has stopped, which is the case with conventional constant phase stop devices, the sewing machine does not automatically start rotating again. (3) A simple circuit can be provided with an auto-needle function, and its repetition period is low. It is possible to adjust the

The embodiments of the present invention will be explained below with reference to the drawings. In Fig. 1, 1 is a power plug, 2 is a general sewing machine controller, 3 is a sewing machine motor, 4 is a changeover switch section, 5 is a control circuit section, and 6 is a current cutoff section. It is a switch for

Reference numeral 41 denotes a connecting piece, which when placed between terminals a and b and between terminals a and c forms an electric circuit of a commonly used electric sewing machine.

That is, when the speed is between a and b, the speed of the sewing machine motor is controlled only by the controller 2, and -
Needle stitch, automatic - Not related to needle stitch.

Next, when the connecting piece 41 is located between A and C, the sewing machine motor 3
Since the diode 42 is inserted together with the controller in the energization path of , the maximum speed of the sewing machine can be kept lower than when it is between a and b.

When the connecting piece 41 is further moved between c and d, a -needle line circuit is formed, and in conjunction with this, the mechanical part (not shown) is also set for one-stitch sewing.

43 and 44 are interlocking switches, and when both are closed, normal needle stitching is performed, and when they are open, automatic needle stitching is performed.

511 is a fuse, 512, 521.527 is a diode, 513, 515.517, 519° 522.523
is a resistor, 516 and 524 are semi-fixed resistors, 518 is a temperature compensation thermistor, 520° and 525 are electrolytic capacitors, 5
28 is a capacitor for noise prevention, 526 is a Zener diode, R is a relay, and R-1 and R-2 are normally open contacts of the relay.

The thyristor 5140 firing circuit is formed by elements 515-527.

The ignition circuit is adjusted by a semi-fixed resistor 524, and controls the thyristor 514 based on the difference between the reference voltage generated across the resistor 5230 and the residual back electromotive voltage of the sewing machine motor, thereby feedback controlling the speed of the sewing machine motor 3 at a constant low speed. It is something to do.

Next, the operation of the one-stitch wire of the present invention will be explained.

In FIG. 1, the power supply path of the sewing machine motor of the single-stitch sewing circuit where the connection piece 41 is located between c and d is formed by the controller 2, the thyristor 514, and the diode 42.

First, the connecting piece 41 is located between c and d, and the switch 43.4
4 is closed. When the controller is depressed, the sewing machine motor 3 starts to drive the upper shaft of the sewing machine at a constant low rotation rate under feedback control.

When the upper shaft rotational phase of the sewing machine reaches a predetermined phase, the upper shaft rotation is stopped by the stop mechanism member, the constant phase detection switch 6 is turned on, and the relay R is activated.
Its contacts R-1 and R-2 close.

When R-1 closes, the thyristor 5140 reference voltage becomes zero, so the thyristor 514 is turned off and the motor supply current is cut off.

When the driving force from the motor is lost, the stop mechanism member is reset by a return spring or the like of the stop mechanism member, and prepares for stopping after the next rotation.

Further, this return causes the switch 6 to return to its original off state.

However, since R-2 is already closed, relay R is self-held in the activated (on) state.

Therefore, even if the controller remains depressed, the motor is not energized.

Furthermore, even if the upper shaft of the sewing machine is manually rotated in this state, the sewing machine will not start rotating unexpectedly.

Next, when the controller is returned to its original open state, relay R is turned off, and all circuits are in their original state.

Therefore, by simply turning the controller on and off, it is possible to safely repeat normal and needle sewing operations.

Next, the automatic needle stitching operation with the switches 43 and 44 released will be described.

In this case, even if relay R is turned on, the circuit at contact R-2 is always open, so the relay is not self-holding.

Therefore, as the switch 6 at constant phase stop is turned off again due to the return of the stop mechanism member from the on state, the relay R returns from the on state to the off state.
Contact R-1 is also released at the same time.

Therefore, as long as the controller is depressed, contact R-
1 is released, the reference voltage of the ignition circuit is generated, the thyristor 514 is turned on again, and the motor starts rotating at a low speed again.

The present invention makes it possible to adjust the time from the time when contact R-1 is released until the thyristor is turned on again, thereby making it possible to adjust the repetition time of the automatic needle stitching operation.

In other words, since the switch 44 is open, the semi-fixed resistor 516 is connected to the charging circuit for the capacitor 525.
The charging time constant is adjusted by this resistor 516, and as a result, the generation time of the firing gate current of the thyristor is controlled.

In addition, because of the normal needle line one-white movement one-stitch sewing, there is no need to intentionally short-circuit and release the resistor 516, but by adjusting the repetition time during automatic needle sewing, the low speed rotation speed during normal needle sewing can be adjusted. This is to prevent it from changing.

Note that the Zener diode 526 is for power supply voltage compensation, and stabilizes the ignition circuit voltage against fluctuations in the power supply voltage.

The temperature compensation thermistor 518 compensates for changes in the operating characteristics of the thyristor 514 due to changes in temperature such as ambient temperature.
- This is to reduce changes in needle rotation speed.

The circuit in Figure 2 uses the relay circuit in Figure 1 as a thyristor 529.
This is another example in which the circuit is replaced with a circuit using.

In FIG. 2, 530 is an electrolytic capacitor and 531 is a fixed resistor.

When the switch 45 is opened and the switch 46 is closed during normal needle sewing, the thyristor 52 is closed by the switch 6 which closes when the upper shaft of the sewing machine reaches a constant phase.
A gate current is supplied to the thyristor 9 and the thyristor is turned on.

As a result, the reference voltage mentioned above becomes zero, and the thyristor 5
14 is turned off and the motor supply current is cut off.

The voltage of capacitor 530 increases as thyristor 5290 turns on.

This is because a part of the main current of the thyristor 529 is bypassed to the gate circuit.

Therefore, even if the switch 6 is opened again after the motor current is cut off, the gate current is supplied to the thyristor 529 by the capacitor 530, and the thyristor 529 is self-maintained in the on state until the controller is released.

Next, in the case of automatic needle stitching in which switch 45 is closed and switch 46 is opened, the gate and cathode of thyristor 529 are short-circuited, thyristor 529 is ignored, and switch 6 directly applies the reference voltage. It plays the role of bringing it down to zero.

As a result, no self-holding circuit is formed, and an automatic needle stitching operation with a constant period is achieved.

Other operations in FIG. 2 are similar to those in FIG. 1.

Fig. 3 shows yet another embodiment, and the differences from the embodiment shown in Fig. 1.2 are as follows: (1) Self-holding circuit during normal needle sewing and repetition during automatic needle sewing. (2) When erasing the reference voltage during normal needle sewing and automatic needle sewing,
1 and 2, the terminals of the electrolytic capacitor 525 are short-circuited, whereas the one in FIG. 3 is short-circuited between the terminals of the resistor 523.

First, to explain the operation during normal-needle sewing, selector switch 4
7 is on the terminal e side.

The self-holding circuit includes transistors Tr1. This is performed by a positive feedback circuit with Tr2.

When switch 6 is open, Trl and Tr2 are off, and thyristor 514 is on.

When switch 6 is closed, base current is supplied to T and Tr2 is turned on.

Then, the base current passing through the resistor 534 is also supplied to the transistor, and T2 is also turned on.

When Trl is turned on, even if switch 6 is opened again, Trl is already turned on.
2 is supplied with the base current from Trl, so T is self-maintained.

When Tr□ is on, the resistor 523 is short-circuited, so the thyristor 514 is turned off.

When the controller 2 is released, Trl and Tr2 are turned off again.

Note that the resistors 532, 534, 536, 538 and the capacitors 533, 537 are circuit components of a self-holding circuit formed by Trl and Tr2, and are usually common design means.

Next, to explain the automatic needle stitching operation, switch 47
is on the f side.

When switch 6 is open, transistor Tr3 is off and thyristor 514 is on.

When switch 6 is closed, capacitor 535 is rapidly charged from capacitor 525' and at the same time Tr3
Tr3 is turned on by supplying a base current to Tr3, and thyristor 514 is turned off.

Even if the switch 6 is then opened again, the charge accumulated in the capacitor 535 passes through the semi-fixed resistor 540 to supply the base current to the Tr3, so that the Tr3 remains on for a certain period of time.

The on duration of this Tr3 is determined by the discharge time constant determined by the capacitor 535 and resistors 540 and 541.

When this discharge is completed, Tr3 is turned off again, thyristor 514 is turned on, motor 3 is rotated, and the switch is closed again, repeating the above operation.

Other operations in FIG. 3 are similar to those in FIGS. 1 and 2.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a single needle line control device for a sewing machine according to the present invention, and FIGS. 2 and 3 are circuit diagrams of another embodiment of the present invention. In the figure, 2 is the sewing machine controller, 3 is the sewing machine motor, and 4 is the sewing machine controller.
6 is a constant phase detection switch, switches 43, 44, 45, 46, 47 are switching members, 514 is a main sill, and resistors 522 and 523 are selector switches for selecting each sewing operation.
are each element of the low-speed control circuit, capacitors 525, 535,
Resistors 516 and 540 are each element of the re-rotation circuit, thyristor 529, relay contact R-1, and transistor Tr2 are each element of the main current cutoff circuit, and capacitor 530, relay contact R-2, and transistor Tr1 are each element of the holding circuit. be.

Claims (1)

[Claims] 1. In a sewing machine equipped with a stop mechanism that forcibly stops the upper shaft at a fixed phase of rotation of the upper shaft of the sewing machine, - a controller that specifies operation and stop of needle stitching, and a controller that is connected in series to the sewing machine motor and that is connected in series to the sewing machine motor; a main thyristor that controls the supply current of the machine; a low-speed control circuit that controls the main thyristor to rotate the sewing machine motor at a low speed; and a switch that is activated by detecting a constant phase of the upper shaft rotation and that is stopped by the stop mechanism. a constant phase detection switch that returns when the sewing machine rotational driving force from the sewing machine motor disappears after the rotation of the sewing machine, and a main current cutoff that acts on the low speed control circuit to cut off the supply current to the sewing machine motor when the constant phase detection switch is activated. Circuit, normal - needle line function and automatic - Kushi”
and a switching member that mutually switches between the sewing function and the sewing function, and the switching member is activated when normal-needle sewing is specified, and after the constant phase detection switch is activated, the supply current of the main current cutoff circuit is changed. a holding circuit that maintains the cutoff state and releases the holding when the controller specifies stop; and a holding circuit that becomes active when the switching member specifies auto-needle stitching and controls the constant phase detection. A single needle line control device for a sewing machine, comprising a re-rotation circuit that acts on the low-speed control circuit to rotate the sewing machine again after a predetermined time has elapsed after a switch is activated.