JPS6019279B2 - Sewing machine single stitch device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that enables single-stitch sewing of an electric sewing machine by operating the sewing machine.

Generally, when changing the sewing direction during the sewing process, extremely high accuracy is required for the needle stop position at the direction change point.

In this case, the accuracy of the needle stop position is obtained by stopping the sewing machine once before a predetermined conversion point and then sewing one stitch. Therefore, from the standpoint of sewing work efficiency, it is necessary that the single stitch be sewn accurately and quickly. Conventionally, to perform this one-stitch sewing, a hand switch was installed separately from the sewing machine's bevel, which resulted in poor work efficiency.Moreover, the sewing speed of machines that operated the single-stitch sewing with the bevel was slow. It was slow and there were problems with work efficiency. The present invention is intended to improve these conventional drawbacks, and makes it possible to perform single-stitch sewing by operating the sewing machine's bevel, and also increases the single-stitch sewing speed to approximately twice that of the conventional method. The purpose is to increase efficiency and accuracy.

The present invention will be explained below with reference to the drawings showing embodiments thereof.

FIG. 1 shows the structure of the sewing machine driving section in the sewing machine of the present invention, where A is a needle position detection device which generates signals corresponding to the needle upper layer and the needle lower layer.

B is an electric motor, C is an electromagnetic brake coil, D is a magnetic rotating plate that is directly connected to the axis E of the electric motor B and can only move in the direction of the axis of the electric motor B, and F is connected to the axis E of the electric motor B via a coupling. This is a sewing machine shaft. When the bevel of the sewing machine is stepped on, motor B rotates. When the bevel is released, motor B is disconnected from the power source, both ends of the armature of motor B are short-circuited, dynamic braking is activated, and motor B is decelerated. When a voltage is applied to the electromagnetic brake coil C, an attractive force acts between the rotating plate D and the electromagnetic brake coil C, and this attractive force acts as a braking force for the electric motor B to stop it. FIG. 2 shows the electric circuit of the device of the present invention, in which 1 is a D-flip-flop (hereinafter referred to as D-FF), 2 is a NAND logic element (hereinafter referred to as NA
3 is an operational amplifier, 4, 5, 6, 7, 8 are transistors, 9 is an N-gate thyristor, 10, 11 are diodes, 12, 13, 14, 15, 16, 17, 1
8, 19, 20, 21, 22, 23, 24, and 25 are resistors, 26 is a capacitor, and 27 is a sewing machine base.

Note that Va is a constant voltage power supply terminal for the control circuit, Vb is a power supply terminal for the oscillation circuit, and Vc is a power supply terminal for driving the motor B.
Further, the resistor 12 constitutes a speed setting signal generation circuit 1 that generates a signal corresponding to the amount of depression of the bevel, that is, a speed setting signal, by a slider interlocking with the bevel 27,
The transistor 5 and the resistors 24 and 25 constitute a pedal depression detection circuit 0 that detects whether or not the beta 27 is depressed. D-FFI inputs the signal from the pedal depression detection circuit 0 and the signal from the needle position detection device A applied to the terminal T, and operates the base input of the control transistor 7 of the motor B together with the transistor 8 and the resistor 23. The operation circuit m is constituted, and the NAND 2, the transistor 4, and the resistors 13 and 15 constitute a positioning speed setting signal generation circuit W which generates a signal only when the hand position is detected. The operational amplifier 3 receives the speed setting signal and the leveling speed setting signal, an N gate thyristor 9, and resistors 16, 17, 18.
, constitutes a comparator that compares the output signal of the sawtooth wave generating circuit V constituted by the capacitor 26, and the transistors 6, 7 and resistors 20, 21, 22 constitute the drive circuit of the motor B. . 28 is a monostable multipipulator (hereinafter referred to as MM) for energizing the electromagnetic brake coil C for a certain period of time.

Next, the operation will be explained.

FIG. 3a shows the output P of the needle position detecting device A, which shows a high potential when the needle is in the lower layer and a low potential L when the needle is in the upper layer.

FIG. 3b shows the output P2 of the beta pedal 27 detection circuit 0. When the beta 27 is depressed, the potential becomes low L, and the beta 27 is depressed.
If you release 7, it becomes a high potential day. Figure 3C shows the Q output P3 of the D-FFI, which becomes a low potential L when the beta 27 is depressed, and a high potential at the lower layer of the needle.Figure 3D shows the NAND
2, and after the beta 27 is released, the potential is low up to the lower part of the needle. 3e shows the output P5 of the speed setting signal generation circuit 1, FIG. 3f shows the output P6 of the positioning speed setting signal generation circuit N, and FIG. 3g shows the output P7 of the sawtooth wave generation circuit V. 3h is the output P of the comparator town.
8 is shown.

When the power is turned on at this point, although it is not shown in the electric circuit in Figure 2, even if the circuit operates only when the power is turned on, D-
Clear the FFI and apply a high potential to its Q output P3 to operate transistor 8, make transistor 7 non-conductive, and disconnect motor B from the power supply. In this state, the sewing machine is not operating at all.Next When the bevel 27 is pressed forward at a certain time, the voltage shown in FIG.
At the same time, the D-FFI is preset by the signal shown in Figure 3C, its Q output P3 becomes low potential L, transistor 7 becomes active, and motor B is activated based on the speed setting signal shown in Figure 3E. and start rotating at low speed.

Next, when the bevel 27 is released at a time ratio of 2, the speed setting signal disappears, as shown in FIG. 3e, and the electric motor B is rotated by the positioning speed setting signal as shown in FIG. 3f.

This speed is determined by the stopping accuracy of the needle and is a constant speed. Also, after releasing the bevel 27, the positioning speed setting signal disappears at time t3 when the first needle lower layer is reached.
In addition, D-FFI is inverted by the rising edge of the signal shown in FIG. At the same time, with MM28, the time ratio is 3
During the operating time of the MM28, the electric brake coil C is energized, the rotary plate D is attracted, and the electric motor B is braked to stop the electric motor B. In this way, one process of sewing a single stitch is completed, and the sewing machine will not operate at all unless the bevel is pressed next. As is clear from the above embodiments, the single stitch sewing device of the present invention includes a speed setting signal generation circuit that generates a speed setting signal corresponding to the amount of depression of the sewing machine's bevel, and a speed setting signal generation circuit that determines whether the bevel is depressed. a bevel depression detection circuit that detects whether the needle is in position, a positioning speed setting signal generation circuit that generates a signal only when the needle position is detected, and a positioning speed setting signal generation circuit that is connected to the speed setting signal generation circuit and the positioning speed setting signal generation circuit. A speed control circuit that drives a sewing machine driving electric motor based on a speed setting signal when the pedal is first depressed by a signal from the circuit, and drives the electric motor according to a positioning speed setting signal when the pedal is next neutral, and the positioning speed setting signal. This device is equipped with a signal generating circuit that generates a signal to apply braking to the electric motor when the needle position is detected after the signal from the generating circuit disappears. It is raised continuously, and after starting the sewing machine, it is moved as far as possible (if you release the bevel, the time t,...
By increasing the positioning speed, the time t can be shortened.
2, t3 can be shortened, and when performing a single stitch, it can be performed accurately and quickly.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view of the main parts of a single stitch device of a sewing machine showing an embodiment of the present invention, Fig. 2 is an electric circuit diagram of the device, and Fig. 3 is a signal waveform of each part of the circuit. It is a diagram. 1... Speed setting signal generation circuit, W... Positioning speed setting signal generation circuit, V... Lock tooth wave oscillation circuit (speed control circuit), W... Comparator ( Speed control circuit), skin... Drive circuit (speed control circuit), B...
...Electric motor, 28... Monostable multipipulator (signal generation circuit for applying braking). Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A speed setting signal generation circuit that generates a speed setting signal corresponding to the amount of pedal depression on the sewing machine, a pedal depression detection circuit that detects whether or not the pedal is depressed, and a positioning circuit that generates a signal only when the needle position is detected. The speed setting signal generating circuit is connected to the speed setting signal generating circuit and the positioning speed setting signal generating circuit, and the signals from these circuits drive the sewing machine driving motor based on the speed setting signal when the pedal is depressed for the first time. , a speed control circuit for driving the electric motor according to the positioning speed setting signal when the next pedal is in neutral, and a signal for braking the electric motor when the needle position is detected after the signal from the positioning speed setting signal generation circuit disappears. A single-stitch sewing device for a sewing machine, which is equipped with a signal generation circuit that generates a signal.