JPH0792193B2 - Light safety device for press machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention forms a light beam around a press machine, and when the light beam is blocked by the intrusion of foreign matter, a stop signal is generated to operate the press machine. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light beam safety device for a press machine, which is capable of starting a press machine by generating a stop release signal when it is stopped and the interruption is released.

[Conventional technology]

The light beam type safety device of the conventional press machine of this type is designed to form a light beam in a single plane, and various types have been developed on the premise of such a single layer light beam.

[Problems to be Solved by the Invention]

Therefore, when the light beam of one layer is interrupted, the operation of the machine is stopped, and when the operation is restarted by the generation of the stop release signal, in consideration of safety, it is not started unless the hard manual switch is pressed. Further, if it is one layer, if the foreign matter detection function is out of order, the safety monitoring function is completely lost.

Therefore, an object of the present invention is to provide a light beam safety device for a press machine that can reliably detect the entry of foreign matter and also reliably detect the recovery of the foreign matter.

[Means for Solving the Problems]

In order to achieve this object, the present invention forms multiple layers of light rays from the outer side to the inner side of the press machine in multiple layers, and inputs a light ray interruption signal of the light rays of multiple layers, and at least one layer is intercepted. Then, a stop signal generation circuit that generates a stop signal that stops the operation of the press machine and the disappearance of the light beam cutoff signal of the innermost light beam to the light ray cutoff signal of the outermost light beam are sequentially detected, and the foreign matter escape signal is detected. There is provided a foreign matter escape signal generating circuit for generating a stop cancel signal and a stop release signal generating circuit for detecting the occurrence of the foreign matter escape signal after the generation of the stop signal and generating a stop cancel signal.

In order to ensure the safety of starting, it is preferable to provide a manual operation switch for starting the press machine by operating with the stop release signal generated from the stop release signal generating circuit. It is also possible to use a remote system owned by.

In order to generate a more reliable foreign matter escape signal, the foreign matter escape signal generation circuit is blocked in order from the outermost ray to the innermost ray, and then the innermost ray interception signal to the outermost ray interception. It is configured to detect disappearance of signals in order. In this case, the stop release signal generating circuit may directly generate the start signal for starting the press machine instead of the stop release signal without providing a manual operation switch for starting the press machine.

Immediately after releasing the light blocking at the end of work, for example, work,
In order to avoid the risk of reflexive actions such as mold setting mistakes, the stop release signal generation circuit is equipped with a timer that slightly delays the generation of the stop release signal. It is extremely effective.

Furthermore, considering that the worker enters inside the light beam, the foreign substance crossing signal is generated by detecting the disappearance of the outermost light beam to the innermost light beam in order. A signal generation circuit and a foreign object reverse penetration signal generation circuit that detects the occurrence of the light blocking signal of the innermost light beam to the light blocking signal of the outermost light beam in order to generate a foreign object reverse penetration signal are provided, and the stop is released. The signal generation circuit
It can be considered that the operation is disabled after the foreign matter crossing signal is input until the foreign matter reverse intrusion signal is input.

[Action]

The stop signal generation circuit generates a stop signal when at least one layer of the light beam is cut off, and stops the operation of the press machine. In this state, the foreign matter escape signal generation circuit detects that the foreign matter escapes from the light beam and disappears in order from the light ray cutoff signal of the innermost light ray to the light ray cutoff signal of the outermost light ray, and detects the foreign matter escape signal. Occur. This allows
The stop release signal generation circuit generates a stop release signal to bring the press machine into a ready state for operation, and operates the manual operation switch to start the press machine. Therefore, it is possible to configure the structure to ensure the same level of safety as the conventional one and to make the operation of the switch easier. When the manual operation switch is a remote type, an operator or the like can start the operation by separating from the apparatus main body.

The foreign matter escape signal generation circuit detects in turn from the outermost light ray to the innermost light ray, and then disappears in order from the innermost light ray cutoff signal to the outermost light ray cutoff signal, When the switch for starting is not provided, when the foreign matter escape signal is generated, the stop release signal generating circuit directly generates the start signal instead of the stop release signal, and the press machine is automatically started.

Further, when the foreign matter crossing signal generation circuit and the foreign matter reverse penetration signal generation circuit are provided, the foreign matter crossing signal generation circuit detects that the worker enters the inside of the light beam, and the foreign matter reverse penetration signal generation circuit causes the worker to detect the light beam. The stop release signal generating circuit becomes inoperable until it comes in from the opposite direction, and subsequently, when the foreign matter escape signal is generated at the time when the escape is completed, the press machine is ready for operation or automatically started.

〔Example〕

1 and 2 show a safety device according to an embodiment of the present invention applied to a press machine.

FIG. 2 shows the upper mold 2 and the lower mold 3 attached to the slide 1.
1 shows a press machine for bending a metal material interposed therebetween into a predetermined shape. Then, a floodlight bracket 10 is attached to one side of the front surface, the light emitting elements 11 _{1 to} 11 ₁₀ are arranged from the upper side to the lower side, and further toward the inner side, the light emitting elements 12 _{1 to} 12 ₁₀ and 13 _{1 to} 13 are arranged. ₁₀ are arranged so that the curtain is formed in three layers on the vertical surface. On the other side, the brackets 20 for light receivers are arranged so as to face each other, and light receiving elements 14 _{1 to} 14 ₁₀ and 15 ₁ to 15 are similarly provided in three layers at positions facing the respective light emitting elements.
₁₀ , 16 _{1 to} 16 ₁₀ are arranged. The light emitting elements 11 _{1 to} 11 ₁₀ form an outer light curtain, and when _{one of} the optical axes incident on each of the facing light receiving elements 14 _{1 to} 14 ₁₀ is blocked, the light beam of the first layer is well known. The cutoff signal S ₁ is generated from an auxiliary circuit (not shown). Similarly, the light receiving element 15 ₁
When any one of the optical axes incident on ˜15 ₁₀ is blocked, the second layer ray blocking signal S ₂ and the inner light receiving elements 16 _{1 to} 16 ₁₀ output the third layer ray blocking signal S ₃ . .

Figure 1 shows a processing circuit portion of these rays interrupting signal S ₁ to S _3. That is, 21 is an OR gate that functions as a stop signal generation circuit, and a drive control circuit 22 that controls the operation of the press machine when at least one of the light blocking signals S _{1 to} S ₃ is input.
To stop signal l.

Reference numeral 23 denotes a foreign matter escape signal generation circuit, which in turn extinguishes from the inner light blocking signal S ₃ to the outer one S _{1 while the} light blocking signals S _{1 to} S ₃ are generated by the insertion of the operator's hand or the like. Is detected and a foreign matter escape signal m is generated. This circuit can be composed of various types of hard logic circuits or CPUs that receive the light beam cut-off signals S _{1 to} S ₃ .

Reference numeral 24 denotes a stop release signal generating circuit, which detects that the foreign matter escape signal m is generated after the stop signal 1 is generated and generates a stop release signal n.

Reference numeral 25 is a touch switch attached to a wristwatch type belt to configure a remote switch for starting the operation of the press machine, and a transmission circuit 25a for generating an ultrasonic beam by its operation is attached, and the transmission beam is A receiving circuit 25b for receiving is attached to the apparatus body. And
When the touch switch 25 is operated while the stop release signal n is generated, the transmission signal is received and the start signal o is supplied to the drive control circuit 22 through the AND gate 26.

The operation is as follows.

During operation of the press machine, when, for example, a worker's hand intrudes and at least one of the light blocking signals S _{1 to} S ₃ is generated, a stop signal 1 is supplied to the drive control circuit 22 through the OR gate 21 to operate the press machine. Will stop. When the inserted hand escapes from the light beam, the light ray interruption signals S _{1 to} S ₃ disappear from the inside in order and a foreign matter escape signal m is generated, so that the stop release signal generating circuit 24 continues to generate the stop release signal n. . In this state, when the operator operates the touch switch 25, the start signal o is output through the AND gate 26, and the drive control circuit
22 starts the operation and at the same time, the stop release signal generating circuit 24
Is reset to stop the generation of the stop release signal n.

In other words, the foreign matter is detected by the multi-layered light beam and its escape is detected, so that not only the abnormality occurrence is surely detected, but also the release thereof is surely detected. As a result, there is no need to specially consider the safety and make it rigid. For example, when a foreign object traverses the inside of the light beam, the stop release signal n is not generated even if the light beam cutoff signal disappears. If only one or two layers of the three layers of light are blocked, the foreign matter escape signal m does not occur even after recovery, but a hand is inserted into the light beam at the time of starting to specifically generate the foreign matter escape signal m. Then, the touch switch 25 is operated.

FIG. 3 shows another embodiment, in which the stop release signal generating circuit 24 in FIG. 1 detects that the light beam cut-off signals S _{1 to} S ₃ are sequentially generated from the outer side and returns, A foreign matter crossing signal generation circuit 28 for detecting that the foreign matter crosses inside the light beam and a foreign matter reverse penetration signal generation circuit 29 for detecting that the foreign matter sequentially blocks three layers of light rays from the inside are attached. As a result, when working inside the light beam, the stop release signal generation circuit 24 becomes inoperable when the worker crosses the light beam, and when the worker finishes the work and enters the light beam from the inside, it enters the operating state and completely escapes. Then, the foreign matter escape signal m is generated, so that the stop release signal n is generated. As a result, the stop release signal n is not generated even if another person cuts off the light beam once the light beam is cut off and an operator enters the inside, and after the light beam is completely traversed from the inside to the outside. The stop release signal n is generated for the first time.

It should be noted that the stop release signal generating circuit 24 in the embodiment of FIGS. 1 and 3 has a built-in timer having a timer time corresponding to the sense of reflexively pushing out a work or die setting error. Only when the stop signal l is not generated again within the time, the stop release signal n is generated corresponding to the foreign matter escape signal m.
It is also conceivable to configure so as to generate. The operation switch of the press machine may be mounted on the main body of the press machine, which is easier to operate than the conventional one, instead of the touch switch described above. In other words, the safety will be further enhanced if the conventional state is maintained.

It is conceivable that the light rays may have two layers or four layers or more. Even in the case of two layers, the cutoff or recovery order of each light ray is similarly determined in consideration of electrical noise and optical malfunction. A highly reliable safety device can be realized. FIG. 4 is a foreign matter escape signal for generating a foreign matter escape signal m when a foreign matter, for example, a hand or an arm intrudes into the light rays of two layers in order from the outside in this manner, and the interruption is released from the inside in order from the state of blocking both. The generation circuit is shown in detail. The other circuit parts are the same as those of the circuit shown in FIG. 1. The two layers of light blocking signals S ₁ and S ₂ are respectively supplied to the OR gate 21 in the same figure, and the foreign matter escape signal m is the stop release signal generating circuit in the same figure. Supplied to 24.

In other words, this circuit is configured such that the first layer of light rays from the outside have a non-blocking state # ₁ , the second layer have a non-blocking state # ₂ , and these blocking states. As shown in FIG. 5, the light ray states a, b, c,
It is configured to detect transitions of d, e, ..., A. Here, states a and 2 are both unblocked,
c and block only the first layer from the inside, e block both layers,
b is from a to c, d is from c to e, is e
Moving from to means moving from to. In these states # ₁ , # ₂ , # ₁ and # ₂ , the ray non-blocking signals S ₁ and S ₂ and the ray blocking signals S ₁ and S ₂ are output,
RS which outputs a signal indicating that the states a, c, e, have been reached by inputting these signals and the delayed signals respectively obtained through the delay circuits 31 to 34 of, for example, about 0.2 seconds The flip-flops 41 to 45, their set input terminals AND gates 51 to 55, and reset input terminal OR gates 61 to 66 and AND gates 71 to 74 are configured to satisfy the following logical expressions. In this logical expression, D represents a delay, and the RS flip-flops 41 to 45 are all reset by the system reset signal and the foreign matter escape signal m.

Therefore, the RS flip-flop 41 outputs the a signal which is set in # ₁ and # ₂ in the normal state.

The RS flip-flop 42 has a state in which # ₁ is delayed, By setting the logical product of and as the set condition, the state is transferred from state a to state b. When it changes to, the c signal is output. It is not set when the state b is not passed. Also, reset conditions If the state does not change to the state e even after a lapse of a predetermined time after changing from the state c to the state c, the state is reset. That is, the c signal is released when only the first layer is cut off and left as it is or when it is pulled out.

The RS flip-flop 43 is in the state c according to the set condition D # _2.
Via state d to state When it changes to, the e signal is output. However, after returning to the state a by the reset conditions a, c, e ... Will be reset even if the state c or the state is reached again 0.2 seconds before.

RS flip-flop 44 changes from state e to state A signal is output when it changes to. However, similarly, when the state changes to the state c via the state b immediately after returning from the state to the state a, or the reset condition After returning from the state to the state e once, the state is reset when the state is changed to the state e again via the state d.

The RS flip-flop 45 outputs a signal when the state changes from the state to the states # ₁ and # ₂ .
Similarly, immediately after that, when the state changes to the state c via the state b, the state is reset.

Thus, for example, when a hand is inserted into the light rays of the two layers and then removed, the c signal, the e signal, the signal and the signal are sequentially generated while the a signal is being generated from the RS flip-flops 41 to 45, and the AND gate These AND signals are output from 75, and the foreign matter escape signal m is output from the delay circuit 76 after 0.2 seconds. If any of the signals disappears for 0.2 seconds, the foreign matter escape signal m is not generated. Further, unless the light beam is interrupted according to the normal work, the above-mentioned reset condition does not generate the sequence signal of the five stages.

Therefore, an extremely reliable foreign matter escape signal m is obtained, and the stop release signal is generated from the stop release signal generation circuit which has this timer as an input and which has a timer for the timer time corresponding to the above-mentioned reflexive hand-out feeling. It is also possible to output n as the starting signal o without the starting switch. That is, automatic start is possible with the interruption of the light beam.

In the present invention, the light emitting element and the light receiving element are arranged on the same side, the mirror is opposed to the opposite side, the light emitting operation of the light emitting element is sequentially switched and scanned, or each light beam is generated in each layer. It can be applied to the safety device that adopts the method.
The light beam can be applied not only to the front surface but also to the side surface.

〔The invention's effect〕

As described above, according to the present invention, by providing a plurality of layers of light rays, a detection error of foreign matter intrusion due to a failure of one of the light rays can be avoided, and safety can be further enhanced. In addition, by detecting the recovery of foreign matter intrusion, the operator does not enter the inside of the light beam to apparently recover the abnormality, or the frequency of accidental recovery of the abnormality is further reduced. The monitoring performance of is improved.

At this time, the detection of foreign matter intrusion is performed based on the disappearance from the outermost light ray to the innermost light ray in order, and then from the innermost light ray cutoff signal to the outermost light ray cutoff signal in order. The safety is further enhanced, and the manual operation switch for starting is abolished, and automatic starting is also possible.

Even when the operation of the press machine is started by the manual operation switch when the stop release signal is generated, there is no problem even if the operation can be easily performed. A remote switch can be easily adopted.

Further, when the foreign matter crossing signal generation circuit and the foreign matter reverse entry signal generation circuit are provided, safety is further ensured when an operator enters inside the light beam.

[Brief description of drawings]

FIG. 1 is a front perspective view of an embodiment of a press machine to which the present invention is applied, FIG. 2 is a diagram showing a circuit configuration of the same embodiment, FIG. 3 is a diagram showing a modified example of the circuit, and FIG. Is a diagram showing a circuit configuration of another embodiment of a two-layer beam type and FIG. 5 is a diagram for explaining the operation of this embodiment. 11 _{1 to} 11 ₁₀ , 12 _{1 to} 12 ₁₀ , 13 _{1 to} 13 ₁₀ ...... Light emitting element, 14 ₁ to
14 ₁₀ , 15 ₁ to 15 ₁₀ , 16 _{1 to} 16 ₁₀ Photo detector, 25 Touch switch.

Claims (7)

[Claims] 1. A light beam is formed around a press machine, and when the light beam is interrupted by a foreign substance, a stop signal is generated to stop the operation of the press machine. In a light beam safety device of a press machine that is capable of starting a press machine, a plurality of layers of light rays are formed from the outside to the inside of the press machine, and a ray cutoff signal of the light rays is input, When at least one layer is cut off, a stop signal generating circuit for generating a stop signal for stopping the operation of the press machine, and in order from the light ray cutoff signal of the innermost light ray to the light ray cutoff signal of the outermost light ray A foreign matter escape signal generation circuit that detects the disappearance and generates a foreign matter escape signal and a stop release signal by detecting that the foreign matter escape signal occurs after the generation of the stop signal Beam safety device for a press machine, characterized by comprising a stop release signal generating circuit for raw. 2. A light beam is formed around the press machine, and when the light beam is interrupted by a foreign substance, a stop signal is generated to stop the operation of the press machine. In a light safety device for a press machine that is generated and can start the press machine, a plurality of layers of light rays are formed from the outside of the press machine to the inside, and a light ray blocking signal of the plurality of layers of light rays is generated. A stop signal generating circuit for generating a stop signal for stopping the operation of the press machine when at least one layer is cut off as an input, and sequentially cutting off from the outermost light ray to the innermost light ray, and then the innermost light ray. A foreign matter escape generation circuit that generates a foreign matter escape signal by detecting disappearance in order from the shutoff signal to the light ray shutoff signal of the outermost ray, and before the occurrence of the stop signal. Beam safety device for a press machine, characterized in that the foreign matter escape signal and a stop release signal generating circuit for generating a stop release signal is detected from occurring. 3. The switch according to claim 1, further comprising a manual operation switch for starting the press machine by operating in a state where the stop release signal is generated from the stop release signal generating circuit. Light type safety device for press machines. 4. The stop release signal generating circuit includes a timer for delaying the generation of the stop release signal, and the stop release is made in response to the foreign matter escape signal only when the stop signal is not generated again within the timer time. The optical safety device for a press machine according to claim 1 or 2, which generates a signal. 5. The light beam safety device for a press machine according to claim 2, wherein the stop release signal generating circuit directly generates a start signal for starting the press machine in place of the stop release signal. 6. The light beam safety device for a press machine according to claim 3, wherein the switch is a remote type carried by an operator. 7. A foreign matter crossing signal generating circuit for generating a foreign matter crossing signal by detecting disappearance in order from the light ray shutoff signal of the outermost light ray to the light ray shutoff signal of the innermost light ray, and the innermost foreign matter crossing signal generation circuit. A foreign matter reverse intrusion signal generating circuit for detecting the occurrence of the light ray blocking signal of the light beam to the light ray blocking signal of the outermost light beam in order to generate a foreign object reverse intrusion signal, and the stop release signal generating circuit, The light beam safety device for a press machine according to claim 1 or 2, which is configured to be inoperable after the foreign matter crossing signal is input until the foreign matter reverse penetration signal is input.