DE3533850A1 - Electronic control apparatus for monitoring the conveying of work-pieces in multi-stage presses - Google Patents

Abstract

The invention relates to a control apparatus for monitoring the conveying of work-pieces in multi-stage presses, having conveying control devices which can be assigned to the stages, and having a shift register which represents the intended allocation and whose serial input is connected to a material control device and whose parallel outputs are connected to a comparator to form the switch off signal. The aim is to design the monitoring to be reliable with a high degree of economy in terms of time and material, to be simple to operate and flexible in use. The object is to achieve this by simple restarting with a different work-piece allocation after fault clearance and by unproblematic bridging of non-controlled stages. The object is achieved in that a memory (6) is connected on the input side to the conveying control devices (B1...Bn) and on the output side to the comparator (7), in that two position-dependent signal devices (K1; K2) serve to actuate the memory and the shift register (5a, 5b), whose parallel inputs (V1...Vn) are connected to the memory outputs to adopt a changed intended allocation. To bridge non-controlled stages, corresponding shift register outputs (A1...An) can be switched over to the associated parallel inputs. In the case of a plurality of independent tool sets, the shift register can be divided into a plurality of parts (5a), (5b). <IMAGE>

Description

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Electronic control device for monitoring the workpiece transport in transfer presses

The invention relates to an electronic control device according to the preamble of the claim, which is shown in Malfunctions, such as gripping errors in the feed device, failure of a workpiece during the Transport, a workpiece getting stuck in the tool or the like, a switch-off signal for the press drive generated. This device is for transfer and transfer presses as well as for press complexes and is synchronous working press lines can be used

Such a known device according to DE-AS 12 03 uses scanning elements to detect the workpieces Limit switches which are arranged on the grippers of the feed device or on the press table. the Evaluation takes place in a relay sliding chain that is clocked by a control cam connected to the crankshaft and the vacancies of the Let the workpiece feed run through without the press being switched off. The disadvantage of this solution can be seen both when pulling the machine during commissioning and when it is restarted after a fault shutdown, for example by removing a damaged workpiece, in these cases is a further pushing through of the fault locations through the remaining levels while maintaining the monitoring function not possible in continuous operation, that is, the press is stopped after each stroke until the Defects have gone through the last stage.

This Uachteil is according to DE-OS 20 32 674 by a electronic circuit arrangement from a slide

register for the target assignment of the levels and a combinatorial logic for the comparison between the actual and target occupancy eliminated. The misplaced positions are connected to the switches assigned to the levels Parallel inputs of the shift register manually acknowledged, which is due to the target assignment updated in the latter enables the press to be restarted in continuous operation. The disadvantage of this known facility consists in the fact that the press is shut down every time due to the lack of workpiece feed will.

Another known electronic control device according to DD-PS 120 831 consists essentially of one Input memory and a storing error display to display blanks and errors and the Storage of the current target occupancy for the next one Press stroke. The transport control devices are direct and the material control device as well the error display outputs of the respective upstream stage are connected to the input memory via OR-UICHT gates. The input memory outputs are via OR-NOT or OTDJ-Gl led it with the error display inputs tied together. Furthermore, there is an OR gate, a pulse shaper and a pulse distributor for deletion the previous status of the error display, a status memory for the error shutdown and a further state memory is provided to ensure that there are empty spaces. After fault shutdown the press and the removal of the faulty workpiece can be done by operating an acknowledgment switch can be put back into operation in the run. This facility is disadvantageous because that the error display is not for the separate representation of target and actual occupancy, i.e. also of empty

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and defects, can be used and that, if a workpiece is not removed after an error message, but is adjusted again, a delete key for the level in question must also be pressed otherwise this workpiece will run through the transfer press in an uncontrolled manner.

All of the aforementioned control devices still have the Disadvantage that they are inflexible with regard to changing control tasks and level assignments.

It is therefore the aim of the invention to monitor the workpiece transport in transfer presses at high To make time and material economy safe, easy to use and flexible to use.

The object of the invention is to provide an electrical control device to create a simple restart with changed workpiece assignment after a fault shutdown and a problem-free bridging of steps that cannot be controlled is permitted.

In a device of the generic type, this object is achieved by the characterizing features of the claim solved.

In a certain position of the feed device, the storage device takes over the signals from the transport control devices and thus records the actual status of the workpiece allocation. The target occupancy is formed with the help of the shift register, the serial input of which with the material control device - For example on a feeder - connected and whose clock input for serial inputs receives a pulse with every working cycle. A

ORIQiMAL

The comparator carries out the set-actual value comparison and generates the switch-off signal for the press in the event of an error. The fact that the target assignment by means of the shift register is an automatic pulling of the machine as well as an automatic blank pass through possible if the material feed is interrupted. By the connection of the outputs of the memory with the parallel inputs of the shift register can be done by pressing of the acknowledgment switch, a new setpoint assignment can be written, which, for example, after responding the control device and removal of a defective workpiece from the press the operational readiness is restored. The bridging of control levels that should not be controlled for technological reasons, for example by switching elements on the control device with which the corresponding parallel outputs of the shift register are separated from the comparator and switched to the associated parallel inputs « To control several independent tool sets in the press, the shift register can be attached to suitable Digits are separated so that the resulting additional serial inputs and the connected additional material control devices - for example, additional feed devices Target assignments can be recorded. In a simple manner, the memory output signals are for representation the actual occupancy and independently of it the shift register output signals can be used to display the target assignment of the transfer press. The position-dependent Signals to control the shift register and the memory can be obtained from the position of the crankshaft derived from the press and / or the position of the feed device «

The invention is to be explained in more detail below using an exemplary embodiment »In the associated Show drawing

Fig. 1: the schematic arrangement of the control devices,

Fig. 2; the basic sequence of movements of a feed system depending on the crank angle the press and the position-dependent signals derived from it,

3s shows the circuit diagram of the electronic control device.

In the embodiment of the invention shown in the drawing, they are designed as proximity switches Transport control devices B1 «.. Bn for detecting workpieces 4 on grippers of a feed device 3 arranged. The feed device 3 arranged on a press table 2 is transported the workpieces 4 according to the sequence of movements indicated in FIG. 2 with each press stroke one tool level further. In the presence of workpieces 4, the transport control devices give Β1,. · Βη a signal to the electronic control device. On a feed device 1 is designed as a proximity switch Material control device BO arranged, which when a workpiece 4 is made available the feed device 1 generates an electrical signal.

The electronic control device essentially consists of a shift register 5a, 5b, a memory 6 and a comparator 7 · It is expedient J ^> advantageously from a positive current imaging

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Logic built up, as this provides a good level of protection against faulty circuits caused by line interruptions or causes earth-shorts could become. In response to a detection pulse 9 in the first angular quadrant of the crank position of a first control curve K1 serving as a position-dependent signaling device is derived to the charging control inputs L of the memory 6, this takes over its set inputs S from the transport control devices BL..Bn generated signals. The output signals of the memory 6 thus correspond to the actual state the workpiece assignment. The memory 6 is reset (erased) via its reset control inputs R by a clock pulse 8, which is in the fourth angular quadrant the crank position is derived from a second control curve K2. With the help of the shift register 5a, 5b, the target state of the tool level occupancy is formed by connecting its serial input I to the material control device BO is connected and the clock input for serial input T with each stroke of the press one Clock pulse 8 receives. Thus, the signals of the parallel outputs AL..An of the shift register 5a, 5b correspond to the Target state of the Y / generation level assignment. The comparator 7 contains one corresponding to the number η of tool stages Number of equivalent elements and compares the output signals of the shift register 5a »5t> with the associated output signals of memory 6. In connection With an interrogation pulse 10, a switch-off signal 11 is generated to switch off the press in the event of a fault. The outputs of the memory 6 are via OR gates 12 with the parallel inputs VL..Vn of the shift register 5a »5b connected. This is how it becomes possible by actuating an acknowledgment switch SO connected to the clock input for parallel input P. to take over the actual state registered in the memory 6 as the new target state.

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With the help of switches S1 ... Sn, the parallel outputs Al · «« An of the shift register 5a, 5b of the Disconnect comparator 7 and connect it to the corresponding parallel inputs Connect Vl .... Vn of the shift register 5a, 5b, can have uncontrolled transport stages

be bridged. By separating the shift register output which corresponds to the bridged transport stage, from the comparator 7 and the thereby permissible omission of the corresponding transport control device results for the associated

Equivalence member always equivalence, so that by the bridged Level no signal to switch off the press can be triggered. The connection of the bridged Stage corresponding shift register output with the associated parallel input via one of the OR gate 12 is required so that when actuated of the acknowledgment holder SO the content of the shift register remains unchanged at this point.

-v 20 The two parts of the shift register 5a and 5b can be separated from one another using an isolating switch Sz. An additional feed device, which is arranged on a second feed device, can be connected to the serial input Iz thus freed up Material control device Bz are connected, so that a second target assignment with the shift register part 5b is detected. This enables the control of two independent tool sets in the press.

OBIOINAL

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Claims (1)

Pat e nt a η sgr uch Electronic control device for monitoring the workpiece transport in transfer presses via position-dependent Signals is controlled and the transport control devices on or between the tool stages or on the feed device as well as one Contains acknowledgment switch and a shift register, the serial input of which is connected to a material control device and whose parallel outputs are connected to a comparator for forming a switch-off signal, characterized in that a memory (6) on the input side with the transport control devices (Β1 ·., Βη) and on the output side with the comparator (7) and via its control inputs (L; R) is connected to position-dependent signal devices (K1; K2) that the parallel outputs (Α1 ··· Αη) of the Shift registers (5a, 5b) switchable independently of one another to the inputs of the comparator (7) and, via OR gates (12) to the equal outputs of the Memory (6) linked to parallel inputs of the same rank (V1.,. Vn) of the shift register (5a »5b) are that the acknowledgment switch (SO) is arranged at the clock input for parallel input (P) of the shift register (5a, 5b) and that the shift register (5a, 5b) can be separated at suitable points if necessary and the resulting additional serial inputs (Iz) with additional material control devices (Bz) are connected. -2-