JP2012081500A - Device enabling press machine to work as non-repeat press machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance a function as a non-repeat press machine as well as maintenability.SOLUTION: In the device enabling a press machine to work as the non-repeat press machine, the control circuit section is achieved not by a board being a fixed circuit but by a commercially available PLC board 1 which has excellent maintainability such as rewritability by using a personal computer, and further, a defect monitoring function is strengthened by using an external safety relay 2.

Description

  The present invention relates to a double fall prevention device for preventing a double fall in a mechanical press such as a crank press.

  Many processing operations in mechanical presses are generally performed in a form called a hand-in die in which the press machine is operated intermittently and the operator puts hands between the dies when the machine is stopped to supply and take out materials. Yes, many of the work accidents in the press work are caused by the operation of the press machine when this is done.

  By the way, as an operation mode of the mechanical press, as long as the operation button is kept pressed from the top dead center position of the crank, which is a stop position, for example, at a height of about 170 degrees where there is no room for the operator to hold his hand. The so-called “safety process” (hereinafter referred to as the “this is the safety process”), which stops when the hand is released from the operation button. Mode, which may be abbreviated as “Anichi” in the book.

  When the crank reaches top dead center, the press machine is supposed to stop, but if the rotation continues due to some abnormality, the slide descends again and a disaster occurs. Such excessive rotation (overrun) may be referred to as “falling twice”, and the press machine may have some overrun monitoring function (double fall prevention function) in its power press structure standard. It is obligatory.

  Patent Document 1 discloses that in such a press, a double fall prevention signal is output by a double fall detection signal, and a restart prevention circuit is provided to temporarily stop at a fixed position near top dead center. There is described a double fall prevention device (overrun monitoring device) for a press machine that can reliably prevent fall.

  This will be briefly described with reference to the drawings.

  FIG. 6 is a configuration diagram of the double drop prevention control portion in the invention described in Patent Document 1, and FIG. 7 is a circuit diagram of the entire press.

  As shown in these figures, the double drop prevention device generally includes an operation state signal detection means 10, a step operation confirmation means 20, a double drop detection means 30, and a double drop prevention signal generation means 40. .

  The operation state signal detection means 10 monitors the operation state of each component of the press operation circuit, and includes a cam detector that outputs a signal when the cam switch is turned on and off, a relay detector that outputs a signal when the relay is turned on and off, and an operation button. The operation button detector that outputs an operation button signal when turned on and off, the restart prevention circuit detector that outputs the restart prevention relay signal, and the like.

  Further, the step operation confirmation means 20 confirms the change state at the same time point of the input operation state signal as a plurality of step operations, and if any step operation is determined to be abnormal, it is prohibited to proceed to the next step. To do. When it is confirmed that all steps are normal, a reset signal RST is output.

  The double drop detection means 30 detects the double drop by counting the rotation state of the crankshaft as a proximity signal, and is cleared by the reset signal RST from the step operation confirmation means 20. However, if any of the components is abnormal, the reset signal RST is not input. If the overrun occurs without stopping at a fixed position, the proximity signal input at a predetermined angle is counted and the fall detection signal DBL is output twice. .

  The double drop prevention signal generation means 40 receives the double drop detection signal DBL and outputs a double drop prevention signal DR1 when entering the next press cycle.

  When the fall prevention signal DR1 is output twice, the contact a of the relay DR1 of the power supply system shown in FIG. 7 is turned off, the solenoid 5 is turned off in the same manner as when the emergency stop button EP1 is pressed, the clutch is disengaged, and the brake Will stop the press.

  Further, in the step operation confirmation means 20, the input order monitoring means judges that the restart prevention relay signal is input earlier than the press operation relay signal, for example, and determines that an abnormality has occurred, and stops proceeding to the next step. At the same time, an abnormal signal is output from the fall prevention signal generating means. Therefore, it is possible to reliably stop suddenly near the fixed position.

JP-A-5-23899

  In the conventional double fall prevention device described with reference to FIGS. 6 and 7, a large number of relays and cam switches are used for each circuit, and if these are all normal, the original double fall prevention function is used. However, there is a problem that stopping at a fixed position is not guaranteed if an abnormality such as relay welding or cam switch shaft breakage occurs.

  On the other hand, what constituted the electronic circuit including the relay which operate | moves with these switches, sensors, etc., and put it together as a board | substrate is put in practical use. A portion surrounded by a broken line in FIG. 6 corresponds to a substrate. However, although the circuit of the board can be compactly arranged, the operation cannot be visually observed, so that it is difficult to cope with an abnormality, and it is usually necessary to replace the board itself with a new one. Since the board is manufactured at the factory in accordance with the circuit, it is naturally expensive, and there is a problem that it is difficult to cope with if the production is stopped depending on the model.

  The present invention replaces the function of the board with a combination of commercially available general-purpose parts, thereby improving the maintenance performance such as inspection, repair, and improvement while maintaining the circuit function as it is, and making the component easy to maintain. The purpose is to further strengthen the fall prevention function by adding.

  The present invention described in claim 1 is an operation state signal detecting means for detecting an operation state signal of each component of the operating circuit of the press machine, and confirms the state of change of the input operation state signal as a multi-step operation. If any step operation is determined to be abnormal, the step operation confirmation means for prohibiting the advance to the next step operation and outputting an abnormal signal, and detecting the rotation state of the crankshaft, the double drop is detected. Double drop detection means for detecting, and double drop prevention for preventing advancing to the next press cycle when this double drop detection signal is input or when an abnormal signal is input from the step operation confirmation means In a twice-fall prevention device for a press machine comprising a signal generating means, the control circuit of each of the means is configured by a programmable controller. It is twice fall prevention device for a press machine according to claim.

  According to a second aspect of the present invention, there is provided a plurality of safety relays on the output side of the programmable controller that are actuated by the double fall prevention signal to disengage an electromagnetic clutch of a press machine and operate a brake. The press machine according to claim 1, wherein the press machine is a double-falling prevention device.

  According to the present invention, updating the software of the programmable controller (PLC) or adding a new function can be carried out simply by connecting to a personal computer, so that it is optional and easy.

  In addition, by using a safety relay that is exposed on the board surface and is attached by a relay socket, there is an excellent effect that the fall prevention function is enhanced twice without impairing maintenance.

It is a front view which shows the PLC board in the double fall prevention apparatus of this invention Example, and its auxiliary equipment. It is a front view of the PLC board in the double drop prevention device of the embodiment of the present invention. It is a circuit diagram which shows the power input part of the PLC board in an Example. It is a part of circuit diagram inside PLC in an Example. It is a part of circuit diagram inside PLC similarly in an Example. It is a block diagram of a twice fall prevention control part. It is a circuit diagram of the whole conventional press machine. FIG. 2 is a circuit diagram of an apparatus according to the present invention. It is explanatory drawing explaining conventionally well-known PLC.

  Embodiments of the present invention will be described below with reference to the drawings.

  Also in the present invention, the basic configuration of the double drop prevention device is the same as that of the invention described in Patent Document 1 described with reference to FIGS. That is, it comprises an operation state signal detection means, a double fall detection means, and a double fall prevention signal generation means. In the case of abnormality, a double fall prevention signal is generated and the press is stopped.

  The operation state signal detection means monitors the operation state of each component of the press operation circuit. The cam detector outputs a signal when the cam switch is turned on / off, the relay detector outputs a signal when the relay is turned on / off, and the operation button. An operation button detector that outputs an operation button signal when turned on and off, a restart prevention circuit detector that outputs a restart prevention relay signal, and the like are included.

  Further, the step operation confirmation means confirms the change state at the same point of the input operation state signal as a plurality of step operations, and prohibits proceeding to the next step when any step operation is determined to be abnormal. . When it is confirmed that all steps are normal, a reset signal RST is output.

  The double drop detection means detects the double drop by counting the rotation state of the crankshaft as an approach signal, and is cleared by the reset signal RST from the step operation confirmation means. However, if any of the components is abnormal, the reset signal RST is not input. If the overrun occurs without stopping at a fixed position, the approach signal input at a predetermined angle is counted and the fall detection signal DBL is output twice. .

  The double drop prevention signal generating means outputs the double drop prevention signal DR1 when the double drop detection signal DBL is input and enters the next press cycle.

  When the fall prevention signal DR1 is output twice, CRY00 and CRY01 connected to the emergency stop line shown in FIG. 8 are turned off, the solenoid is turned off and the clutch is disengaged in the same manner as when the emergency stop button EP1 is pressed. The press machine stops because the brake is applied.

  Further, in the step operation confirmation means, the input order monitoring means determines that the restart prevention relay signal is input earlier than, for example, the press operation relay signal, and determines that it is abnormal, and stops proceeding to the next step. An abnormal signal is output from the fall prevention signal generating means twice. Therefore, the emergency stop can be surely performed in the vicinity of the fixed position.

  As described above, in some conventional press machines, the signal processing and the control of each actuator have been replaced with a single substrate. However, the first feature of the present invention is that the control portion has a substrate. Instead, a PLC is used.

  The PLC is an abbreviation of Programmable Logic Controller, and is also called a programmable controller, and is a control device for FA incorporating a microcomputer (CPU) and a memory as shown in FIG. Processes signals from input devices such as various sensors and switches to control output devices such as solenoid valves, motors, and indicator lights. Program can be freely written and changed using PC application software. What can be done is a major difference from a substrate whose circuit is determined in the manufacturing stage. The program uses a “ladder program” based on a sequence diagram.

  The second feature of the present invention is that a self-diagnosis relay called a safety relay is externally added to the PLC, thereby improving the reliability of the apparatus and facilitating maintenance such as relay replacement. I was able to do it.

  Also in the present invention, the configuration of peripheral devices such as the operation state signal detection means, the step operation confirmation means, the double drop detection means, and the double drop prevention signal generation means is the same as that of the invention described in Patent Document 1, In the embodiment described in the above, the description is omitted. In FIG. 6, an area surrounded by a broken line is a portion to be controlled by the PLC. The control part for controlling these means will be described below.

  FIG. 1 is a front view showing a PLC board and its associated equipment in the double drop prevention device of the present invention. Reference numeral 1 is a PLC board, reference numeral 2 is an external safety relay, reference numeral 3 is a direct current that is an operating power source for peripheral equipment. (DC) A power supply that supplies 12V.

  If the PLC is a normal battery-less type, no battery is required.

  The safety relay 2 can be easily replaced by attaching it using a relay socket.

  FIG. 2 is a front view of the PLC board 1. Reference numeral 11 denotes a main body of the PLC, reference numeral 12 denotes an input / output terminal block, and reference numerals 13a to 13d denote LED indicator lamp groups.

  The PLC of the embodiment includes four indicator lamp groups 13a to 13d.

  The first indicator lamp group 13a is for displaying the operating state of the PLC. “POWER” indicates that the power is on, “RUN” indicates that the PLC is operating normally, and “ERROR” indicates an abnormality. Is displayed.

  In the second indicator lamp group 13b, the numbers “7” and “10” indicate that the overrun detection proximity switch has detected a dog, and the numbers “11” and “12” indicate that two safety relays are provided. Lights when turned off. The number “13” indicates that the “safe one stroke” is currently selected, and it is possible to detect an abnormality in the constant input state of the restart prevention cam input. On the other hand, the number “14” is turned on when the press does not select the safety one stroke and the wiring is short-circuited, and indicates that the restart prevention circuit is not monitored.

  In the third indicator lamp group 13c, the number “0” is when the restart prevention cam is in the valley, the number “1” is when the operation button is pressed, the number “2” is the press operation, that is, the clutch is ON. Lights when. Number "3" is lit when the restart prevention circuit condition is satisfied, number "4" is lit when the reset button is pressed, and number "5" is lit when the fixed position stop cam is in the valley.

  In the fourth indicator lamp group 13d, the numbers “0” and “1” are “emergency stop outputs” indicating the operating state of the safety relay, and are turned on when normal, and turned off when an abnormality is detected. These “0” and “1” displays are synchronized outputs, and the emergency stop circuit itself is also monitored by duplicating the circuit.

  The number “3” selects inching or continuous operation, and the number “0” in the third indicator lamp group 13c lights up at the falling edge of the restart prevention cam signal, and when this lights up, it falls twice. Is not detected. The number “4” lights up when there is an abnormality in the emergency stop output.

  The number “5” is “slip abnormality”, and lights when the overrun occurs beyond the top dead center stop position due to slipping of the clutch in safe operation. The number “6” is “proximity abnormality”, and is lit when the input of the proximity switch does not enter normally or when the input is always in the input state.

  Similarly, the number “7” is “restart prevention cam error”, and if the restart prevention cam input does not enter normally, or if the input is always in the input state, the number “10” is “stop in position” Lights when the input of the fixed position stop cam does not enter normally due to "cam error" or when the input is always in the input state. The number “11” is “abnormality of restart prevention circuit”, and is lit when the input of the restart prevention cam is not normally entered or when the input is always in the input state. However, as described above, in order to detect an abnormality in the constantly input state, it is necessary to select and input “safety process”.

  As described above, the double drop prevention device of the present invention always monitors and displays the presence or absence of abnormality in the control circuit even during normal operation.

  3 to 5 are part of a circuit diagram realized by the PLC.

  FIG. 3 shows an input portion from the alternating current (AC) 100 V to the PLC board 1. Connect AC100V to the D0 and D16 terminals, and connect the ground to the E terminal.

  FIG. 4 shows safety relays in the circuit diagram, where the upper half is a PLC input circuit and the lower half is a PLC output circuit. Since X11 and X12 are respectively connected to the b contacts of two safety relays CRY00 and CRY01, the LED display is turned off by the operation of the relay.

  In FIG. 5, the upper half is a PLC input circuit and the lower half is a contact circuit. The a contact of the two safety relays CRY00 and CRY01 is connected in series, and the b contact is connected in parallel, so the emergency stop circuit is a double system, and the self-diagnosis function of the emergency stop circuit is added to prevent malfunction. Improves reliability.

  Although the above configuration can be surely realized until an emergency stop signal is sent to the press, there is no guarantee that the press will actually stop at a fixed position if there is a mechanical slip in the clutch or brake part. However, in the present invention, there is a “slip abnormality” lamp in the indicator lamp group 13d, and an alarm can be issued even in such a case. In addition, as a means to supplement the double drop prevention device of the present invention, a dual valve solenoid valve with an abnormality monitor is adopted as a countermeasure against exhaust failure of the solenoid valve, and an emergency solenoid valve is attached to the clutch / brake air piping to By ensuring that the exhaust is performed even when the exhaust of the valve is defective, it is possible to strengthen the countermeasure against the double drop caused by the machine side and improve the reliability.

  DESCRIPTION OF SYMBOLS 1 ... PLC board, 2 ... Safety relay, 3 ... Power supply, 11 ... PLC board main body, 12 ... Terminal block, 13a-13d ... Indicator light group, 10 ... Operation state signal detection means, 20 ... Step operation confirmation means, 30 ... Two drop detection means; 40 ... Two drop prevention signal generation means.

The invention according to claim 2, turn clutches of the press machine is operated by the twice drop prevention signal, claims a plurality of safety relays for actuating the brake formed by providing on the output side of the programmable controller The press machine according to claim 1, wherein the press machine is a double-falling prevention device.

Claims (2)

An operation state signal detecting means for detecting an operation state signal of each component of the operation circuit of the press machine;
Step operation confirmation means for confirming the state of change of the input operation state signal as a multi-step operation and prohibiting the advance to the next step operation when any step operation is determined to be abnormal and outputting an abnormal signal When,
A double drop detection means for detecting a double drop by detecting the rotation state of the crankshaft;
A press provided with a double fall prevention signal generating means for preventing advancing to the next press cycle when the double drop detection signal is inputted or when an abnormal signal is inputted from the step operation confirmation means. In the machine double fall prevention device,
A double fall prevention device for a press machine, wherein the control circuit of each means is constituted by a programmable controller.   The press machine according to claim 1, wherein a plurality of safety relays are provided on the output side of the programmable controller to actuate the electromagnetic clutch of the press machine by operating according to the double drop prevention signal and operate the brake. apparatus.

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