JPH1125810A - Safety switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent dangerous operation by enabling a safety door to be unlocked by a manual operation when the safety door is closed, and a key member is set at a predetermined position of a switch body and by keeping a lock member in an unlocked state by means of a spring action when the safety door is not closed or a control signal is turned off by a power failure or the like. SOLUTION: While a safety door 6 is opened, a lock solenoid 22 and a lock- release solenoid 33 are not energized, a lock block 20 is lowered through the action of a lock spring 23, and a lock-release block 30 is pressed against the side surface of the lock block 20 through a lock-release spring 32. A forced release key 4 is inserted and turned into a normal condition other than a power cut-off condition such as power failure or the like, the lock-release block 30 is moved leftwards but the lock solenoid 22 maintains a current-carrying state, so that the lock block 20 continues to lock a key 2 without being lowered. In normal condition, a forced release of the lock cannot be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety fence surrounding an industrial machine, which prevents the industrial machine from operating unless the entrance door is completely closed, thereby preventing the human body from being caught or caught by the industrial machine. The present invention relates to a safety switch to be mounted on an entrance for prevention.

[0002]

2. Description of the Related Art A safety switch is installed as an interlock for an industrial machine at a doorway or the like of a safety fence. When pressed, the key is inserted into the switch body to close the electrical contacts. By incorporating this electrical contact signal into one of the conditions of the industrial machine drive circuit, the industrial machine can be stopped when the safety door is opened. However, some industrial machines rotate or operate due to inertia even after the operation is stopped.In such a case, even after the safety door is opened, the hazardous condition to the workers continues, and although safety has been completely secured. Absent.

[0003] Therefore, there is a safety switch provided with a lock mechanism that cannot be easily opened after the safety door is closed, that is, the key cannot be pulled out freely.
An example of a safety switch with this mechanism is Telemecani
There is a safety switch represented by model XCK-J598 (hereinafter referred to as known example 1) manufactured by que. This has a key having a locking means operated by a solenoid. When the key is inserted into the switch body, the locking means is activated by energizing the locking solenoid by a control signal from the control device, and the key is mechanically locked to prevent the door from being opened. It is. When it is desired to release the lock, the lock member for fixing the key is forcibly retracted by turning the forcible release key attached to the switch body, and the lock is released. That is, the key is locked by turning on the solenoid.

Japanese Patent Application Laid-Open No. 64-14834 (hereinafter referred to as "known example 2") discloses that when a key is inserted into a switch body, the key is locked by a mechanical locking means provided in the switch body so as not to be pulled out. Such a safety switch is disclosed. In releasing the lock, the solenoid of the lock release means is energized by a release control signal from the control device, and the lock member, to which the key is fixed, is retracted by the solenoid to release the lock. That is, the solenoid is turned on to release the lock.

[0005]

However, the safety door switch as described above has the following problems. In the known example 1, when the power supply to the control device is interrupted due to a power failure or the like, the solenoid is turned off, the lock is easily released, and the door can be opened and closed. Some industrial machines operate by inertia for a while even after the machine operation is stopped, which may cause a worker to be caught and caught.

In the second prior art, when the power is cut off, the solenoid cannot be energized, so that the key cannot be unlocked and the door cannot be opened at all. For this reason, measures have been taken to forcibly release the locked state and allow the door to be opened and closed by attaching a switch or key for forcibly releasing the lock. In some cases, there is a possibility that the door may be opened using a key or switch for forced release during operation of the industrial machine, and there is a risk that the door may be caught during operation of the machine. Therefore, the present invention, after closing the safety door, not only can not be opened unless an open command is issued from the control device, even if the power supply to the control device is interrupted due to power failure, etc., and maintain the locked state, and An object of the present invention is to provide a safety switch in which the lock cannot be forcibly released in a normal state other than when the power is turned off.

[0007]

SUMMARY OF THE INVENTION The present invention comprises a switch body and a key member which is attached to either a safety fence or a safety door. The switch body has a safety door closed and a key member provided on a predetermined portion of the switch body. A switch that detects this state when set to a position, a lock member that locks and unlocks the key member in a controlled manner, a lock member release member that locks and unlocks the lock member in a controlled manner, and a lock member release It has a forcible release means capable of moving the member to the unlock position by manual operation. The present invention is preferably such that in a state in which the safety door is not closed and a state in which the control signal is interrupted due to a power failure or the like, the lock release member is provided with a spring so that the lock member is in a position for holding the unlocked state by a spring action. It is preferable that the lock position is maintained by the action.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the safety switch according to the present invention will be described below. As shown in FIG. 1, the safety switch includes a key 2 attached to a safety door 6 and a switch body 1 attached to a fixed portion of a safety fence 5. Switch body 1
A case 3 having a key insertion opening for inserting the key 2, a lock means 10 in the case 3 for preventing the key 2 from being pulled out of the switch body 1, and a lock release means for acting on the lock means 11 and unlocking means 11
Lock releasing means 12 acting on the switch body 1 and the switch body 1
And a key insertion detection switch 40 for detecting the state of insertion of the key 2 into the key. The key insertion detection switch 40 is a safety door 6
Is turned on when it is completely closed, and the signal is transmitted to a control device (not shown).

The lock means 10 includes a lock groove 2A of the key 2.
Lock block 20 that locks key 2 by being inserted into
A lock plunger 21 connected to the lock block 20, a lock solenoid 22 acting to push up the lock plunger 21 when energized upward (looking toward the paper surface; the same applies hereinafter), and the other end of the lock plunger 21. It is constituted by a lock spring 23 which is connected and pulls this downward.

[0010] The lock release means 11 is a lock block 2
Unlocking block 30 capable of mechanically restricting the ascending / descending operation of the lock 0, an unlocking plunger 31 connected to the unlocking block 30, and an unlocking solenoid 3 for operating the unlocking plunger 31 to the left when energized.
3 and an unlocking spring 32 that is set between the unlocking solenoid 33 and the unlocking block 30 and that pushes the unlocking block 30 to the right.

The unlocking means is combined with the unlocking means, and is provided with a groove 30A provided in the unlocking block 30.
A lock release block 34 for rotating the lock release block 30 to the left by the pawl by rotating the lock release block 30; A lock release rotation bar 34A which penetrates outside the case 3 of the switch body and has a key groove 34B at an end thereof, and a lock release rotation block 34 inserted through the key groove 34B and through the lock release rotation bar 34A. Is provided with a forcible release key 4 for rotating.

The operation of the safety switch will be described below with reference to FIGS. When the safety door 6 is open, the lock solenoid 22 and the lock release solenoid 33 are not energized as shown in FIG. 3, and the lock block 20 is actuated by the lock spring 23 as shown in FIG. The lock release block 30 is lowered, and is pressed against the side surface of the lock block 20 by the action of the lock release spring 32.

When the safety door 6 is closed, the key insertion detection switch 40 is turned on by the key 2 as shown in FIG.
And sends a key insertion detection signal to the control device. When the control device receives the key insertion detection signal, the lock solenoid 2
An energization command is issued to 2 (FIG. 3). As shown in FIG. 2C, when the lock plunger 21 operates against the force of the lock spring 23, the lock block 20 is raised (A).
Direction) and locks the key 2 into the lock groove 2A of the key 2. When the lock block 20 moves up, the lock release spring 32 acts to release the lock release block 30.
Is pushed to the right (C direction) to lock block 20
To prevent the lock block 20 from lowering. Thereafter, the control device issues an operation command to an industrial machine (not shown). During the operation of the industrial machine, the above state is maintained, and even if the safety door 6 is to be opened, the key 2 is locked, and the safety door 6 cannot be opened.

When the control device determines that the industrial machine has completed the predetermined work and the inertial rotation has completely stopped, first, the energization of the lock solenoid 22 is cut off (FIG. 3). When the power to the lock solenoid 22 is turned off, the lock block 20 attempts to descend (in the direction B) due to the action of the lock spring 23. However, since the lock release block 30 has entered the lower part of the lock block 20, it cannot descend. At this stage, the key 2 is still in the locked state.

Next, when an energization command (FIG. 3) is issued to the lock release solenoid 33, the lock release solenoid 32 is actuated.
By moving the lock release block 30 to the left (D direction), the lock block 20 that has been prevented from moving by the lock release block 30 can be moved,
The key 2 is unlocked by descending (direction B) (see FIG. 2).
(D)). Thereby, the safety door 6 becomes movable and can be opened. After that, the energization of the lock release solenoid 33 may be appropriately cut off.

Next, the case where the lock of the key 2 is forcibly released in a state where the power is cut off due to a power failure or the like while the industrial machine is operating will be described. Figure 2 above with key 2 locked
When the power is cut off in the state of (c), the lock solenoid 22 is turned off (FIG. 4). For this reason, the lock block 20 tends to move downward (direction B) by the action of the lock spring 23, but the lock block 20 can move down because the lock release block 30 remains in the lower part of the lock block 20. Key 2 cannot be removed. That is, the key 2 keeps the locked state.

A method of unlocking the key 2 in this case will be described with reference to FIG. When the forcible release key 4 is inserted into the key groove 34B and rotated in the direction E (FIG. 4), the forcibly released rotation bar 34A and the forcibly released rotation block 34 are rotated, and locked by the claw of the forcibly released rotation block 34. The release block 30 is pushed to the left (D direction). By forcibly retracting the lock release block 30 in the left direction (D direction) in this manner, the lock block 20 is pulled downward (B direction) by the action of the lock spring 23 because the lock solenoid 22 is not energized. To unlock the key 2.

As described above, the power can be forcibly released when the power is cut off due to a power failure or the like, but cannot be forcibly released in other normal states. This will be described below. When the forcible release operation is performed in a normal state other than the state where the power is cut off due to a power failure or the like, for example, in the state of FIG. 2C, the forcible release key 4 is inserted as shown in FIG. When the lock release block 30 is turned in the E direction, the lock release block 30 moves to the left (in the D direction). However, since the lock solenoid 22 is kept energized, the lock block 20 continues to lock the key 2 without descending. Have gone. That is, the lock cannot be forcibly released in the normal state.

In the above description, the key 2 is placed on the side of the safety door,
Although the key body 1 is attached to the fixed portion of the safety fence, even if the configuration is reversed, the function does not change at all. Further, the mutual combination and operation of the lock means, the lock release means, and the lock forcible release means can be appropriately modified and applied based on the concept of the present invention. For example, the lock means and the lock release means described in the present embodiment are replaced with each other, the tip of the lock release block 30 of the lock release means is inserted into the lock groove 2A of the key 2, and the lock block 20 of the lock means is locked. It may be mounted below the release block 30. At this time, the lock forcible release means is combined with the lock release means as described above. In this case, it can be dealt with by changing the energization timing of the lock solenoid 22 and the lock release solenoid 33. First, when the safety door 6 is open, the lock solenoid 22 is not energized, the lock block 20 is kept moving leftward, the lock release solenoid 33 is energized, and the lock release block 30 is retracted downward. If this is done, the safety door 6 can be freely opened and closed. The control circuit for energizing each solenoid thereafter can be easily set. Further, instead of a solenoid using electric energy as it is, an actuator using fluid energy such as air or hydraulic pressure can be used.

[0020]

As described above, the safety switch of the present invention not only cannot open the safety door when the safety door is closed and the control device is in the key lock control state, but also performs the forced unlocking operation of the key lock. This cannot be performed when the control device is in the key lock control state, but can be performed only when the power is cut off due to a power failure or the like. Therefore, it is possible to prevent the safety door from being accidentally opened during the operation of the industrial machine or the safety door from being forcibly released. In addition, the safety door cannot be opened unconditionally during a power failure and cannot be opened without a forced release operation, so when the industrial machine is still rotating due to inertia, the safety door is opened immediately and the safety fence is opened. Dangerous work of getting inside can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a safety switch according to the present invention.

FIG. 2 is a diagram illustrating the operation of the safety switch according to the present embodiment.

FIG. 3 is a diagram showing signal timing between devices during normal control.

FIG. 4 is a diagram showing an inter-device signal timing (forced release) at the time of power shutdown.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Switch body 2 Key 3 Case 4 Force release key 5 Safety fence 6 Safety door 10 Lock means 11 Lock release means 12 Lock forced release means 20 Lock block 21 Lock plunger 22 Lock solenoid 23 Lock spring 30 Lock release block 31 Lock release plunger Lock release Spring Lock release solenoid Lock release rotation block Key insertion detection switch

Claims (2)

[Claims] 1. A switch body comprising: a key member for attaching each to a safety fence or a safety door; and the switch body, when the safety door is closed and the key member is set at a predetermined position on the switch body. A switch for detecting a state, a lock member for locking and unlocking the key member in a controlled manner, a lock member unlocking member for locking and unlocking the lock member in a controlled manner, and an unlock position for manually operating the lock member unlocking member. A safety switch, characterized in that it has a forcible canceling means that can be moved to the safety switch. 2. In the safety switch, in a state in which the safety door is not closed and a state in which a control signal is interrupted due to a power failure or the like, the locking member is in a position to hold the unlocked state by a spring action. 2. The safety switch according to claim 1, wherein the member releasing member is located at a position for holding the locked state by a spring action.