SU384241A1 - DEVICE MANAGEMENT WORK NITENABLESTERS - Google Patents

Description

one

A device is known for controlling the operation of thread watchers of a sewing machine, comprising thread breakage sensors and an electronic control circuit implemented on semiconductor elements.

The purpose of the invention is to control the breaking of the threads operating at a variable speed. For this, the proposed device contains two counting stages, two tilting circuits, a diode assembly, an “IET” logic circuit, switches and a switching amplifier.

The counting stages are connected on the one hand to the overturning circuit, its circuit and thread control sensors or switches connected to this circuit, which are alternately connected through the base of one of the two tipping circuit transistors and the diode chains, and on the other to the output of the circuit "NO through the diode assembly. In this case, the logic circuit "PET, depending on the number of revolutions of the shaft of the sewing maschine, generates a pulse arriving at the counting device, which, in turn, is connected to a switching amplifier.

The drawing shows the electrical circuit of the device described.

It contains a sensor / pulse that is synchronized with the shaft of the sewing machine, two tilting circuits 2 and 3 with an output

4 and two counting stages 5 and 6. Stage 5 has transistors 7 and 8, dividers 9 w. 10 voltages, capacitors // and 12, diodes 13 and 14 are resistances / 5 and 16, and stage 6 is transistors 17 and 18 and capacitor 19.

Stages 5 and 6 are connected to the tilting circuit 20, equipped with two transistors 21 and 22, and through diodes 23-26 with switches 27 and 28. At the same time, steps 5 and 6 are connected to the output of the logic circuit PET 29 and through diodes 13 and 14 sec. switching amplifier 30. The stages are equipped with switches 31-34. The device also contains a diode 35 mounted on the input of circuit 2, diodes 36 and 37,

connected to the transistor 38 of the amplifier 30,

diode 39, magnet 40, dividers 41 and 42 nanometers, and transistor 43.

At each turn synchronized

A negative pulse appears with the sensor sewing shaft / output 4 of the circuits 2 and 3, which is used to switch the first stage 5. The transistors 7 and 18 are conductive in the position corresponding to the digital value "zero without pulse appearance."

In the first stage 5, a weak negative voltage relative to the mass, corresponding to the signal O, arises, and with the help of dividers 9} 1 10, the base of transistor 7 acquires a positive potential, and transistor 7 becomes nonconductive. A signal L then appears at the input of the first stage 5. The capacitor // is then charged through the resistance 15 and the transistor 7, which becomes conductive. When the signal L passes the input to the signal O, the capacitor 11 is discharged through diode 13, the transistor 7 becomes nonconductive again, and the transistor 8 is conductive. Stage 5 tilts to another position and the signal L appears at the output of the second stage 6. Similarly, this signal discharges the second stage 6 when capacitor 12 discharges. At the input of stage 5 of the second input signal L, the capacitor 12 is recharged 16 and the transistor 8. With the subsequent transition of the L-O signals, the transistor 8 again becomes non-conductive, and the transistor 7 becomes conductive. Stage 5 is tilted to its previous state. At the same time, the stage 6 tilts. Transistor 17 becomes non-conductive and transistor 18 becomes conductive. At the third input pulse, only one first stage 5 changes its state, and at the fourth input pulse, the state of both stages 5 and 5 again corresponds to the initial one. For all subsequent input pulses, the process is repeated in the same sequence. At the same time, on switches 31-34 steps 5 and b, after each input pulse, signals up to the third input pulse appear, which allow to unambiguously determine the number of passed pulses in accordance with the table. After the next fourth input pulse, the initial position is re-created. Depending on the connection of the diodes 36 and 37 to one of the switches 31-34 when the thread breaks in the circuit of the amplifier 30, a signal L appears, which overturns the circuit. When this happens, the transistor 43 becomes conductive and the magnet circuit 40 is closed. Moving the bark magnet 40 separates the mechanical connection of the foot pedal and the electric motor and starts the normal braking process. In this case, the diodes 36 and 37 are connected in such a way that after the third rotation of the sensor / during the initial time interval, the signal L appears in the circuit of the switching amplifier 30. At the same time, the switching amplifier 30, acting as a drive, retains its position. Then, through the diode 35, a signal O is applied to the input of the circuit 2, whereby the upper needle position is established. In the next period of time, the disconnection process ends, the amplifier 30, under the influence of the signal O transmitted through the diodes 13 and 14, overturns. The excitation of the magnet 40 also ends. At the same time, the signal O izmenta.t voltage on the dividers 9 to 10 to the counting stages 5 and 6 is returned to its original position, which is maintained until through the scheme 3 a signal appears with the new sewing process. If there is no thread break and the sewing process does not stop, using switches 27 and 28, which open or close depending on the movement of the controlled thread, both counting steps 5 and b return to their original position. In the closed position of one of the switches 27 or 28, a positive impulse appears on the bases of both transistors 21 and 22 of the circuit 20. When the pulses thus generated are alternately supplied to the inputs of the circuit 20, the latter continuously moves from one position to another. If, however, a pulse appears on only one of the two inputs of circuit 20, this means the presence of a thread break and circuit 20 maintains an unchanged position. With each tilting circuit 20, a positive pulse through diodes 23 and 24 or 25 and 26 is fed to the reset inputs of both counting stages 5 and 6. The initial time interval is chosen so that the switches 27 and 28, in the absence of a thread break, cause this interval time tilting circuit 20. It continuously restores the original position of the counting stages 5 6, and the speed of recovery is proportional to the number of revolutions of the shaft of the sewing machine. The subject of the invention A control unit for the operation of thread garners of a sewing machine, comprising thread breakage sensors and an electronic control circuit made on semiconductor elements, characterized in that, in order to control the breakage of threads, which operate at variable speed, it contains counting stages, two tipping hems, the diode assembly, the logic circuit NO, the switches and the switching amplifier, the counting stages being connected on the bottom with a tilting circuit and coders on the coitrol and switches or switches Interlocked with this circuit, which are connected one by one through the base of one of the transistors of the tilting circuit and the iodine chains, on the other hand, with the selection of the circuit "NO through the diode assembly, with the logical circuit" NO depending on the number of revolutions of the shaft of the sewing machine A pulse arrives at the counting device, which is connected to a switching amplifier.

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