SU1493491A1 - Device for automatic correction of press shaft brake angle - Google Patents

Abstract

FIELD OF THE INVENTION The invention relates to mechanical engineering, in particular to the design of control systems for mechanical presses. The purpose of the invention is to improve the accuracy and stability of the stop of the press ram. Commands to stop the press shaft, and therefore the slide, come from the sensors of the control unit connected to the press drive. In this case, the inputs of the reversible counter are received through the elements 2 and the pulses from the reference frequency generator and from the output of the voltage-frequency converter connected to the drive speed sensor. The signals from the output of the reversible counter go through the memory block to the executive relay, the contacts of which are included in the control circuit of the clutch-brake inhibitor electromagnet. Thus, when the press operates with an adjustable drive speed, an automatic correction of the shaft braking angle and, consequently, the stop of the slide is achieved. 2 Il.

Description

(L

; ik

00

one

2a 3

press control

- AT

The invention relates to mechanical engineering, in particular to the design of control systems for mechanical presses.

The aim of the invention is to improve the accuracy and stability of the stopping of the press slide.

FIG. 1 shows a functional diagram of the device; in fig. 2 - angular diagram of the operation of sensors of the command and control.

The device contains a reversible counter of 1 pulses, the generator of the reference frequency 3 is connected to the forward counting input (+) through element 2И 2 and the first sensor 5 is connected through the first memory block 4, to the input of the counting return (-) via element 2И 6 converter 7 voltage-frequency tachogenerator 8 speeds of the main drive and through the second memory block 9 - the second sensor 10, and an output relay 11 is connected to the output through the third memory block 12, the reset input of which (element 2IHE 13 is connected to press control circuit. Memory blocks 4, 9 and 12 Turning on two identical elements 2I-NO (14, 15; 16; 17; 18, 13) and inverters 19, 20 and 21. The sensors 5 and 10 are within the composition of controller, with the articulated shaft of the press.

The device works as follows.

When the clutch-brake is turned on, a signal is given to reset the block 12 (input of element 2ID-NOT 13), and a signal is deduced that prevents the clutch-brake from engaging. The clutch-brake is engaged and the press shaft starts rotating. When the controller passes point A (see Fig. 2), the sensor 5 is briefly turned on and a signal is output to the unit. 4 memory, which stores it and gives permission through the element 2И 2 to the pulse count by the reversible counter 1 on the direct count input from the generator 3 of the reference frequency. When further rotation of the shaft at point B, the sensor 10 is briefly turned on and the signal is given to block 9, which memorizes it, and to the reset (input of element 2I-NOT 15) of memory block 4, and the counting of pulses from the reference frequency generator 3 is turned off. At the same time, the memory block 9 provides the resolution through the zemle 2I 6 to the pulse count by the reversing counter 1 on the counting input from the tachogenerator 8 of the main drive via the voltage-frequency converter 7. If the counted pulses are equal, the direct and reverse counting inputs at the output of the reversible counter I produce a signal that resets the memory block 9 (input element 2И– NOT 17) and turns off the counting pulses from the tachogenerator 8 of the main drive. At the same time, this signal is memorized by a memory unit 12 and output to an executive relay 11, which by its

closing contact 22 turns off the clutch-brake electromagnet 23. When this occurs, braking (point C) of the shaft of the press and the stop of the slide at the top dead center (TDC) occurs. The cycle is finished.

The increment of the braking angle Ap while increasing the frequency of the press strokes is

ten

,(one

Where

five

Os.1 - the angle set between the sensors 5 and 10 - f const frequency of the reference frequency generator; fiiH4 far - frequency converter

voltage-frequency

and the following frequency ratio is observed:

fnH4iriin fru f fmax

Thus, when the press operates at an adjustable speed (i.e., by changing the number of strokes), the braking angle of the press shaft is automatically corrected, and therefore, the required accuracy and stability of the slide stop in the initial position is achieved. This determines the efficiency of use of the device.

thirty

Claims (1)

Invention Formula Device for automatically correcting the deceleration angle of the press shaft, containing two sensors of the commander, connected to the main drive of the press, made in the form of an electric motor with an adjustable rotational speed press, characterized in that, with the aim increase the accuracy and stability of the press slide stop; it is equipped with a reversible pulse counter, a reference frequency generator, a speed sensor in the form of a tachogenerator, two 2I elements, a voltage-frequency converter and three memory blocks, each of which is made in the form of two 2I-HE elements connected in series with the inverter, with the first inputs of both elements 2I connected to the outputs of the first and second memory blocks, the second input of the first element 2I is connected to the output of the reference frequency generator, and the second input of the second element 2I is connected to the outputs of the voltage-frequency converter, the input of which is connected to the output of the tachogenerator, and the outputs of both elements 2I are connected to the inputs of the forward and reverse counting of a reversible counter, the output of which is connected to the information input of the third a memory unit whose output is connected to an executive relay, the closing contact of which is included in the circuit of the press brake clutch control electromagnet, while the output of the first sensor of the command device is connected to the information input of the first memory block, and the output of the second The sensor of the control unit is connected to the information input of the second memory block, the reset inputs of the memory block are connected: the first to the output of the second sensor of the control unit, the second to the output of the reversing counter, and the third to the output of the press control circuit. (rie, g