JPS5917319B2 - Press equipment equipped with a failure check function for optical safety devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a press device equipped with a failure checking function of a light beam safety device.

Light beam safety devices are used in press machines and the like to ensure safety.

This light beam type safety device projects one or more light beams into a dangerous area, and when this light beam is blocked by a part of the human body, it outputs an emergency stop signal, and this signal causes the press machine to stop. It is designed to stop the slide, etc.

By the way, the above-mentioned conventional optical safety device has a light emitting element that projects a light beam.If an abnormality occurs in the light receiving element that receives this light beam or the peripheral circuit thereof, it may no longer function as a safety device. If you put your hand, etc. into the dangerous area without noticing this, it is very dangerous because you may lose your hand, etc.

Therefore, in view of the above-mentioned circumstances, a device for detecting abnormalities in light-emitting elements and light-receiving elements has been devised (see Japanese Patent Application No. 52-80212 (see Japanese Unexamined Patent Publication No. 54-14079)). Disclosed in "Failure Detection Device for Optical Safety Devices").

This invention embodies the incorporation of a failure detection device into a press machine as disclosed in the above-mentioned Japanese Patent Application No. 52-80212, and is designed to improve safety when operating the press machine. The present invention aims to provide a press device equipped with a failure checking function for the optical safety device.

According to this invention, the failure detection device is activated by a command to start operation of the press device, and the light emitting element of the optical safety device is
The light receiving element and its peripheral circuits are checked for failures, and if they are normal, the press equipment is enabled to operate in conjunction with the operation start command, and if a failure is detected, the operation is prohibited, and the press equipment is activated. The operation of safety devices is checked immediately before starting operation.

The present invention will be described in detail below based on an embodiment of the accompanying drawings.

First, a failure detection circuit that detects a failure of a light receiving element and a light emitting element will be described.

In FIG. 1, the light emitting signal generator 1 is a light emitting element 2at2b.
Light emission signals Sa, sb, for causing t2ct2d to emit light,
This light emission signal 5a-
8d is applied to each of the light emitting elements 28 to 2d via two-man NAND circuits 3a, 3bt3c, and 3d.

The light emitting elements 28 to 2d project light beams onto a dangerous area such as a slide passing portion of a press machine, and are made of, for example, light emitting diodes.

Light receiving elements 4a, corresponding to the light emitting diodes 28 to 2d,
4bt4ct4d are arranged.

When the light receiving elements 48 to 4d receive the light beams projected from the light emitting elements 28 to 2d, they output a light reception signal, and this signal is added to the synchronization circuit 5.

Further, the synchronization circuit 5 is supplied with light emission signals 5a to 8d from the light emission signal generation circuit 1.

The synchronization circuit 5 matches the light emission signals Sa to Sd and the corresponding light reception signals, and if both signals are present, outputs the signals to the corresponding output lines la, tb, tc, and td.
Furthermore, the light emitting signal is outputted, but if there is no corresponding light receiving signal, it is assumed that the light beam is blocked and no signal is output to the corresponding output line.

This synchronous circuit 5 can be constructed using a group of AND circuits, etc., which take an AND condition between the light emission signals Sa to Sd and the corresponding light reception signals.

The emergency stop signal generation circuit 6 aggregates the signals on the output lines ta-td of the synchronization circuit 5, and outputs a bi-level signal if all of the signals are present, and outputs a low-level signal if there is no signal in any of the signals. It outputs a level signal,
This circuit 6 can be composed of, for example, a four-man power AND circuit.

The output of the emergency stop signal generating circuit 6 is applied to the relay coil 1, and when the output of the circuit 6 is at bi level, the relay coil 1 is excited, and when the output of the circuit 6 is at low level, the relay coil γ is demagnetized.

As will be detailed later, the relay coil γ is
When demagnetized, relay contact γa (shown in FIG. 2) is opened to give an emergency stop signal to the press.

Contacts 34d, 3γc, 38d and 40f shown in FIG.
are normally closed contacts or normally open contacts that are controlled to open and close depending on whether the relay coils 34, 37, 38 and 40 shown in FIG. 2 are energized or de-energized, respectively.

As will be described later, the relay contacts 34ay37c, 38d, and 40f all open when the switch is turned on to start machine operation, and the light emitting elements 2a to 2d and the light receiving elements 48 to
4d failure detection operation is started.

The NOR circuit 9 and the NOR circuit 10 form a flimp flopped/F, and when the signal at the input S of the NOR circuit 9 becomes a low level, the output Q of the NOR circuit 9, which is a cent output, goes to a high level, and the NOR circuit 9 becomes a low level. When the input R of the circuit 100 becomes low level, the output Q of the NOR circuit 9 becomes low level.

Further, the output Q of the NOR circuit 10 is an inverted output of the cent output Q, and this signal is applied to the reset terminal R of the counter 12 via the inverter 11.

The counter 12 is a binary counter, and the counting is done manually.
A signal from a NAND circuit 11, which will be described later, is added to , and counts up when the signal from the NAND circuit 11 falls.

The count value of the counter 12 is added to the decoder 13 and converted to BCD.
converted to code.

Therefore, when the count value of the counter 12 is O, only the output line LO indicating O of the decoder 13 is at a low level, and the signals on the remaining output lines L, -L9 indicating 1 to 9 are at bi level.

The capacitor 30 is used to reset the flip-flop F/F when the power is turned on.

That is, when the power is turned on, the voltage of the capacitor 30 rises from the low level to the bi level depending on the time constant determined by the resistance value of the resistor 29 and the capacitance value of the capacitor 30. The circuit was initially cleared.

It is now assumed that relay contacts 34d, 37c, 38d, and 40f are open, and the count value of counter 12 is O.

At this time, the input S of the NAND circuit 9 forming the flip-flop F/F becomes low level, and the output Q of the NAND circuit 9 becomes low level.
is bi-level.

This signal is applied to the NAND circuit 15a.

The NAND circuit 15a is a two-man powered NAND circuit, and the other input terminal is the output line L of the decoder 13.

A signal inverted by the inverter 14a is added to the signal.

Here, since the a↑ value of the counter 12 is 0, the output line L of the decoder 13.

The signal is at low level, the NAND condition of the NAND circuit 15a is satisfied, and the low level signal is passed to the NAND circuit 3a.
Add to.

As a result, the NAND circuit 3a is closed, and the light emission signal Sa from the light emission signal generation circuit 1 is cut off.

Note that the other NAND circuits 3b and 3c. 3d, the signals of the output lines L1, L2 and tL3 of the decoder 13 are connected to the husband b
The signal inverted by the inverter 14bt14ct14d and the output of the NAND circuit 17 are commonly added together with the output of a two-man NAND circuit 15by15ct15d, and at this time, the output lines L1, L2, L3 of the decoder 13 are added.
Since the outputs of are all high level, the NAND circuit 15 b
The NAND condition of t15ct15d is not satisfied, and the NAND circuits 3by3c and 3d are all opened (.

Therefore, only the light emitting element 2a corresponding to the light emission signal Sa is turned off.

As a result, the output of the light receiving element 4a corresponding to the light emitting element 2a disappears, and at the same time, the signal on the output line ta of the synchronizing circuit 5 also disappears, and the output of the emergency signal generating circuit 6 becomes low level.

The output of the emergency stop signal generation circuit 6 is inverted by an inverter 16 and applied to a NAND circuit 17.

The NAND circuit 17 consists of a two-man NAND circuit, and the signal from the output line L3 of the decoder 13 is input to the other input terminals of the inverter 14d1, the NAND circuit 15d, and the jumper wire 18.
It was added via (・ru.

Here, since the signal on the output line L3 of the decoder 13 is at the .-- level, the output of the inverter 14d is at the low level, and the NAND condition of the NAND circuit 15d is not satisfied, and the signal applied to the NAND circuit 1.gamma. becomes the .-- level.

Therefore, the NAND condition of the NAND circuit 11 is satisfied, and a signal falling from a high level to a low level is added to the counter 12's counting power CU.

As a result, the color/receiver 12 performs count amplification.

Then, the output line L of the decoder 13.

The signal on the output line L1 changes from low level to high level, and the signal on the output line L1 changes from high level to low level.

Output line L.

When the signal reaches the . . . level, the NAND condition of the NAND circuit 15a no longer holds true, and the output of the NAND circuit 15a becomes the . . . level, opening the NAND circuit 3a and lighting the light emitting element 2a again.

Also, at this time, since the output of the NAND circuit 11 is at a low level, the NAND conditions of the NAND circuits 15b to 15d no longer hold, and eventually all the light emitting elements 28 to 2d turn on, so the output of the emergency signal generation circuit 6 becomes a high level, the NAND condition of the NAND circuit 1γ no longer holds true, and its output becomes a high level.

Then, this time, output line L. Since the signal is at a low level, the NAND condition of the NAND circuit 15b is immediately established, a low level signal is applied to the NAND circuit 3b, the light emitting signal sb is disconnected, and the light emitting element corresponding to the light emitting signal sb is 2
Clarify b.

Therefore, the output signal of the light receiving element 4b corresponding to the light emitting element 2b disappears, the output of the emergency signal generating circuit 6 becomes low level, and the counter 12 performs count amplification at the falling edge of the output of the NAND circuit 17.

In this way, the NAND conditions are satisfied in the NAND circuits 15a to 15d sequentially according to the count value of the counter 12, and the outputs of the NAND circuits 15a to 15d cause the NAND circuits 3a to 3d to
scan to close sequentially.

That is, from the light emitting signal generation circuit 1 to each of the light emitting elements 28 to 2d
The light emitting devices 28 to 2d are scanned so as to sequentially cut off the light emitting signals Sa to Sd applied to the light emitting elements 28 to 2d.

As a result of this scanning, when the count value of the counter 12 becomes 3 in decimal notation, the output of the output line L3 of the decoder 13 becomes low level 9, and the NAND condition of the NAND circuit 15d is satisfied.

Therefore, the output of the NAND circuit 15d becomes low level, and this signal is applied to one input terminal of the NAND circuit 1γ via the jumper wire 1B, so the NAND circuit 11 remains open and the count of the counter 12 is Stop.

In addition, the output of the NAND circuit 15d taken out via the upper d-pi jumper line 18 is inverted by the inverter 19.
It is added to the human powered NAND circuit 20.

The other input terminal of the NAND circuit 20 is connected to the relay contact 34.
Signals from d, 37ct, 38d and 40f and a signal from relay contact 7c, which opens when the relay coil T is energized, are added.

This Linley contact 34d, 3rct38d and 40f
The signals from these relay contacts 34d and 37c.

When 38d and 4()f are all open, the level is low, and when even one is closed, the level is high.

In addition, the signal from the relay contact 1c is grounded via a resistor 211, and when the relay contact 1c is closed (that is, when the relay coil 1 is not excited), it becomes an level, and the relay contact 7c is open. and becomes a low level.

Therefore, relay contacts 34d, 3γct38a and 4
0f is closed, the NAND condition of the NAND circuit 20 is satisfied, and the low level signal is passed to the flip-flop F.
'/F is added to the input terminal of the NOR circuit 100, which is the reset terminal R.

As a result, the output of the NOR circuit 10, which is the inverted output Q, is...
This signal is applied to the reset terminal R of the counter 12 via the inverter 11, and the counter 12 is reset.

When the counter 12 is reset, the output of the decoder 13 is on line L.

Since all the signals except for the signals of NAND circuits 15a to 15d become high level, and the output of NOR circuit 9, which is the output Q of the flip-flop F/F, also becomes low level, the NAND conditions of NAND circuits 15a to 15d no longer hold, and the NAND conditions of NAND circuits 3a to 3d are all opened.

As a result, the output of the emergency stop signal generating circuit 6 becomes high level, and the checking of all light beams is completed.

The above explanation is based on the light emitting elements 2a to 2d and the light receiving elements 4a to 4.
Regarding the operation when there is no abnormality in the light emitting elements d and their peripheral circuits, there are light emitting elements 28 to 2d. Even if scanning is performed so as to sequentially cut off the light emission signals 5a to 8d applied to the emergency signal generating circuit 6, the output of the emergency signal generating circuit 6 does not reach the E level, and the relay coil 1 remains demagnetized.

FIG. 2 shows an embodiment in which the failure check function according to the present invention is applied to the control of a press machine.

Each relay contact in Fig. 2 is given the same numerical number among the relay coils 31 to 40.
Opening/closing is controlled by demagnetization.

For example, the relay coil 31 has relay contacts 31a and 31b.
t31c.

31d corresponds to this, and when the relay coil 31 is demagnetized, the state is "closed", "open", "open", open", and when the relay coil 31 is energized, the state is "open", °Closed"', 1
"closed", "closed".

In addition, relay contact γa. γb,? A is a contact that is opened and closed by the relay coil γ shown in FIG.

Rotary cam switch RCLS1. RCLS2゜RC
LS3. RCLS4 is a switch that operates in different ways depending on the stroke angle of the press machine (hereinafter referred to as press stroke).

In this embodiment, each of the above switches RCLSI 4
The switch LS4' is set to turn on when the press stroke is at an angle shown by diagonal lines in FIG.

The relay coils 31 to 40 are each connected in parallel to a power source, and each relay coil 31 to 40 is excited when all the switches connected in series to each relay coil are turned on.

For example, relay coils 31, 32 and 33 are connected to rotary cam switch RCLS1. RCLS2 and RCLS3
are each excited by turning on.

In addition, the relay coil 34 has relay contacts γd, 37a
, 38a, 39ay, 36a, and 31a are all turned on to be excited.

Note that the relay contact 34a is a contact for self-holding of the relay coil 34.

Relay coils 36 and 37 are similarly excited and are self-held by relay contacts 36b and 3γb.

Relay coils 38 and 39 are energized or demagnetized in response to operation of operation pushbuttons 41 a and 4 l b for starting operation of the press machine.

In this embodiment, the relay coil 38 is energized and the relay coil 39 is deenergized to operate the press machine only when both operation push buttons 41at41b are depressed.

Relay coil 40 connects relay contacts 34c, 38c and 3
It is energized when all relay contacts 9b are turned on, and is self-held by relay contact 40d when all relay contacts 31d, 32b, and 36d are turned on.

Clutch brake relinoid valve 42 is energized by turning on relay contact 40e when relay coil 40 is energized.

The press machine is operated by energizing the clutch/brake solenoid valve 42.

The emergency stop circuit 43 is a slide of the press machine (not shown)
This is to stop the

Relay contacts γa, 40c, 34c, 33b and rotary cam switch RCL S 4 are connected to this emergency stop circuit 4.
3 operating conditions are determined.

That is, contacts γa and 40c, switch RCLS4
Alternatively, only when the contacts 31c and 33b are all open, the emergency stop circuit 43 is operated to stop the power supply to the clutch brake renoid valve 42 and stop the sliding of the press machine.

In this embodiment, when the slide of the press is descending (in other words, when the press stroke is in a dangerous range), switch RCLS4 and contact 40c are turned off, and contact γa is activated (i.e., when the press stroke is in a dangerous range). An emergency stop is activated when a hand or other object enters the danger area.

In addition, when the slide of the press rises (in other words, when there is little danger, the switch RCLS4 is turned on, and either or both of the contacts 31c and 33b are turned on, and the contact γa is turned off. It is also designed so that an emergency stop does not occur.

Here, -flJ of the operation of the failure check mechanism constituted by the circuit shown in FIGS. 1 and 2 will be explained.

Assume that the slide of the press has stopped at the top dead center (press stroke 00).

At this time, when the power is turned on, only 38d of the relay contacts 34d, 3γct 38d and 40f shown in FIG. ), the input S of the clip-flop circuit F/F becomes bi-level, and the human power R becomes bi-level with a slight delay due to the action of the capacitor 30, and as a result, the output Q becomes bi-level, and the counter 12 is initial cleared. .

In addition, the output Q becomes a low level, and the NAND circuits 15a to 1
None of the NAND conditions 5d is satisfied, and therefore all the elements 28 to 2d are not scanned and are all lit.

Then, the output of the emergency stop signal generation circuit 6 becomes bi-level, and the relay coil 1 is excited.

Also, at this time, the rotary cam switch R in Fig. 2
As shown in FIG. 3, only switches RCL3 and RCL4' of CL1 to RCL4' are turned on.

From the above, in this case, the relay coil is relay coil 33.
Only 39 and 39 are stable in the excited state.

Here, when the operation pushbuttons 41a and 41b are pressed, the relay coil 39 is demagnetized and the relay coil 3B is energized.

When the relay coil 38 is excited, the relay contact 38d in FIG. 1 is turned off, and the relay contacts 34d and 3γc are turned off.
t38d and 40f are all turned off, and the input pin of the clip-flop circuit F/F becomes low level.

Therefore, the output Q of the clip-flop circuit F/F becomes bi-level, the NAND condition of the NAND circuit 15a is satisfied, and the count value of the counter 12 is O), all the elements 28 to 2d and the light receiving elements 4a to 4d described above A failure check is started.

When a failure check is being performed, the output of the emergency stop signal generating circuit 6 is at a low level, so that the relay coil γ is demagnetized.

Therefore, as shown in FIG. 2, the relay contact 7b is turned on and the relay coil 31 is energized (the relay contact 38b is turned on by pressing the push buttons 41a and 41b, and the relay contact 38b is turned on by pressing the push buttons 41a and 41b,
(c and 34e are both on because the relay coils 36 and 34 are demagnetized).

When the relay coil 3γ is turned on, the relay contact 37b is turned on, and the IJ relay coil 31 is self-held.

In addition, the relay contact 3γC in Fig. 1 is turned on, the input S of the clip-flop circuit F/F becomes a NO level, and the signal (output Q of the flip-flop circuit F/F) for starting the failure check starts to be checked. Return to previous state (low level).

When all the elements 28 to 2d and the light receiving elements 48 to 4d operate normally and the failure check operation of → is completed, the output of the emergency stop signal generation circuit 6 becomes bi-level, and the relay coil 1 is excited.

By excitation of the relay coil γ, the relay contact 7d in FIG.
is turned on, and the relay coil 34 is excited (because the relay contacts 37a, 38a, 39a, 36a, and 31a are already on at this time).

This relay coil 34 is self-held by a relay contact 34a.

By the way, the generating elements 28 to 2d and the light receiving element 4a
4d is out of order, the output of the emergency stop signal generation circuit 6 will not be bi-level, and therefore the relay coil 1 and even the relay coil 34 will remain demagnetized, and the subsequent operation will proceed. I won't.

When the relay coil 34 is excited, the relay contact 34e is turned off, the relay coil 31 is demagnetized, and self-holding is released.

As a result, the relay contact 3γC in FIG. 1 is turned off, but before that the relay contact 34d is turned on, so that the input S of the clip-flop circuit F/F maintains the bi-level.

Furthermore, the relay contact 34c is turned on by the excitation of the relay coil 34, and current flows from the relay contact γa or 40c to the relay coil 40 via the emergency stop circuit 43 and the relay contacts 34cy38cy39b, and excites the relay coil 4o.

Excitation of the relay coil 40 turns on the relay contact 40e, which causes the clutch brake solenoid pulp 42
is excited and press operation is started.

Also, at this time, the relay contact 40c connected to the emergency stop circuit 43 is turned off, so the emergency stop circuit 43 is activated by turning off the relay contact 7a, that is, all the elements 28 to 2d and the light receiving elements 48 to 4d. It becomes operational when a hand or the like crosses between them.

As soon as the press starts operating and the slide begins to descend, the rotary cam switch RCLS3 is turned off (
(See Figure 3).

At the same time, the C-tally cam switch RCL S4 is also turned off, and the rotary cam switch RCLS4 linked to this is turned off.
' turns on.

Therefore, the rotary cam switch RCLS4' and the relay contact 34by3 are connected to the relay coil 35.
2ay 40a and 33a are all turned on, and the relay coil 35 is excited.

This relay coil 35 is self-held by a relay contact 35a.

When operation is started and the press stroke has not reached the vicinity of the bottom dead center, the rotary cam switch RCLS1 is turned off as shown in Fig. 3, so the relay coil 31 is not energized and the relay contact 31d is not energized. It is turned off.

Therefore, in this section, the relay coil 40 cannot be held by itself by the relay contact 40d. For example, if the operation pushbuttons 41a and 41b are turned off at this time, the relay coil 40 is demagnetized and the clutch brake solenoid valve 42 is also demagnetized. The slide stops descending.

At this point, when the operation pushbuttons 41a and 41b are turned on again, operation is resumed after performing the series of failure checks described above.

When the slide descends and the rotary cam switch RCLS2 is turned on, the relay coil 32 is energized, and when the rotary cam switch RCL S 1 is turned on, the relay coil 31 is energized, and this energization of the relay coil 31 turns on the relay contact 31b. Relay coil 36 is energized.

This relay coil 36 is self-held by a relay contact 36b.

Also, almost at the same time as the rotary cam switch RCLSI is excited, the rotary cam switch RCL S4 is turned on, and the progress of the input to the emergency stop circuit 43 is through the relay contact γ.
In addition to a, a path for a rotary cam switch RCLS4 and a relay contact 31c is formed.

Therefore, after this time (in the example shown in FIG. 3, after the press stroke reaches near the bottom dead center), the light emitting element 28
2d and the light receiving elements 48 to 4d become inoperable.

This is because there is no need to activate the safety device when the slide is rising after pressing.

When relay coils 31, 36 and 32 are turned on,
Relay contacts 31d, 36d and 32b turn on,
Relay coil 40 is self-held by relay contact 40d.

When the relay coil 40 is self-held, the operation push button 41 is activated.
Even if a and 41b are turned off, the relay coil 40 is not demagnetized.

That is, during the period when the slide reaches the bottom dead center from just before the bottom dead center and further reaches the top dead center, the operation pushbuttons 41a and 4 are pressed.
Even if 1b is turned off, the machine will not be stopped.

By the way, when the relay coil 31 is excited, the relay contact 31a is turned off and the relay coil 34 is demagnetized.

As a result, the relay contact 34d shown in FIG. 1 is turned off, but since the relay contact 40f is already turned on at that time, the input S of the flimp float circuit F/F continues to maintain the low level.

When the press stroke reaches around 270°, the rotary cam switch RCLS3 turns on and the relay coil 33
Excite.

As a result, the relay contact 33a is turned off, and the self-holding of the relay coil 35 is released.

The slide will rise further and the press stroke will be approximately 30d)
When the temperature is near, the rotary cam switch RCLSI is turned off, which turns off the relay contact 31d and releases the self-holding of the relay coil 40.

Therefore, the clutch brake solenoid valve 42 is demagnetized, the machine stops operating, and the slide stops near top dead center.

Further, by releasing the self-holding of the relay coil 40, the relay contact 40b is turned off, the self-holding of the relay coil 36 is also released, and all the relay coils are returned to their initial states.

Then, by turning on the operation pushbuttons 41a and 41b again, the series of operations starting from the failure check is repeated.

As explained above, according to the present invention, in a press machine equipped with a light beam safety device, a malfunction of the light beam safety device is checked before starting the press device. This has the effect of improving safety when operating the device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a failure detection device for a light beam safety device applied to this invention, FIG. 2 is a block diagram showing an embodiment of this invention, and FIG. It is a figure which shows →l of the operation|movement of the rotary cam sinch shown in the Example. DESCRIPTION OF SYMBOLS 1... All original signal generation circuit, 28-2d... Light emitting element, 4a-4d... Light receiving element, 5-... Synchronization circuit, 6...
- Emergency stop signal generation circuit, 12... Binary counter, 13... Decoder, γ, 31-40... Relay coil, RCL S 1 - RCLS 4, RCLS4'
...Rotary cam switch, 41a, 41b...Operation pushbutton, 42...Franch brake solenoid valve, 43...Emergency stop circuit.

Claims (1)

[Claims] 1. A light beam safety device that projects at least one light beam into a critical area and outputs an emergency stop signal to the press operation circuit by interrupting this light beam, and an input of a light emitting element that projects the light beam. In a press machine comprising a failure check circuit that scans signals in a sequential manner and detects whether or not the optical safety device operates normally based on this scanning, a command to start operation of the press machine is provided. a circuit that operates the failure check circuit based on the operation of the failure check circuit; a circuit that enables the press apparatus to operate in conjunction with the operation start command when no failure is detected as a result of the operation of the failure check circuit; and a circuit that enables the press apparatus to operate in conjunction with the operation start command; A press apparatus, characterized in that the press operation circuit is combined with a circuit that disables the press apparatus when the press apparatus is detected.