JP2004259712A - Lock type safety switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safety switch in which a safety door cannot be opened unless an open directive is given by a control device after the safety door is closed, in which a lock state is retained even in the case a power supply interception to the control device occurs because of power failure or the like, and in which forced release of the lock cannot be carried out at the normal time except the time of interception of the power supply. <P>SOLUTION: This lock type safety switch is composed of a key member and the switch main body respectively mounted onto a safety fence or the safety door. The key member has a fixed part, and the switch main body has a lock means provided with a fixed member to be engaged with the fixed part of the key member, and a plunger which is capable of moving in a longitudinal direction and pushes the fixed member at one end by a solenoid or a spring, a lock release means which is provided at a regulating part to regulate movement of the plunger of the lock means at one end, which is capable of moving in the longitudinal direction, and goes in the one end direction by a solenoid or the spring, and in which the regulating part is pushed, and a forced release means in which the regulating part is retreated from the plunger of the lock means in such a state that the plunger of the lock means is regulated by the regulating part. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a safety fence surrounding an industrial machine, by preventing the industrial machine from operating unless the entrance door is completely closed, thereby preventing the human body from being caught and trapped by the industrial machine. The present invention relates to a lock-type safety switch to be mounted.

Safety switches are installed at the entrance and exit of safety fences as interlocks for industrial machinery. For example, a key is attached to the entrance door (hereinafter referred to as the safety door) side, and a switch body is attached to the fixed side. It is inserted into the body so that the electrical contacts close. 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 and 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.

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.
As an example of a safety switch provided with this mechanism, there is a safety switch represented by Model XCK-J598 (hereinafter referred to as known example 1) manufactured by Telemecanique. This has a key provided with 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 a forcible release key attached to the switch body to release the lock. That is, the key is locked by turning on the solenoid.

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

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.

Further, in the case of the known example 2, when the power is cut off, the key cannot be unlocked because the power supply to the solenoid becomes impossible, and the door cannot be opened at all. For this reason, measures have been taken to forcibly release the locked state and open and close the door by attaching a switch or key for forcibly releasing the lock. In some cases, the door may be opened using a key or switch for forced release during operation of the industrial machine, and there is a possibility 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 opening command is issued from the control device, even if the power supply to the control device is cut off 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.

  One embodiment of the present invention is a lock-type safety switch including a key member attached to either a safety fence or a safety door and a switch body. The key member has, for example, a groove-shaped fixing portion. The switch body has a lock unit, a lock release unit, and a forced release unit. The locking means includes a fixing member that engages with the fixing portion of the key member, and a plunger that is movable in the longitudinal direction and that presses the fixing member at one end by a solenoid or a spring. Accordingly, the key member is fixed by the fixing member engaged with the fixing portion, and the fixed state is maintained by the fixing member being pressed by the plunger. The unlocking means includes a plunger provided at one end with a restricting portion for restricting the movement of the plunger of the locking means, the plunger being movable in the longitudinal direction and being pressed toward the one end by a solenoid or a spring. I have. The movement of the plunger of the lock means is restricted by restricting the movement of the plunger of the lock means by the restricting portion of the plunger of the lock release means, and the above-mentioned fixed state is safely maintained. The forcible release means retracts the restriction part from the plunger of the lock means when the restriction part of the plunger of the lock release means restricts the plunger of the lock means. Therefore, even when the power is cut off due to a power failure or the like, the restraint of the movement of the plunger of the locking means by the regulating part of the plunger of the unlocking means is released, the fixing member of the locking means is detached from the fixing part of the key member, and the key member is released. Is extracted from the switch body. If the plunger of the lock unit is pressed by a solenoid that is excited by a command from a control device and the plunger of the lock release unit is pressed by a spring, the power supply to the control device may be interrupted due to a power failure or the like. However, the locked state is maintained, and the lock is not forcibly released in normal times other than when the power is turned off.

  As described above, the safety switch of the present invention can not only open the safety door when the safety door is closed and the control device is in the key lock control state, but also forcibly releases the key lock when the control device performs the key lock operation. It cannot be performed in the 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 from being forcibly released to open the safety door. At the time of a power failure, the safety door cannot be opened unconditionally 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.

One embodiment of the safety switch of 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. The switch body 1 has a case 3 having a key insertion opening for inserting the key 2, a lock means 10 in the case 3 which acts to prevent the key 2 from being pulled out of the switch body 1, and acts on the lock means. It has a lock release means 11, a lock forcible release means 12 acting on the lock release means 11, and a key insertion detection switch 40 for detecting the insertion state of the key 2 into the switch body 1. The key insertion detection switch 40 is turned on when the safety door 6 is completely closed, and transmits the signal to a control device (not shown).

  The lock means 10 locks the key 2 by being inserted into the lock groove 2A of the key 2, a lock plunger 21 connected to the lock block 20, and a lock plunger 21 when energized. (The same applies to the following.) The lock solenoid 22 is configured to push up the lock plunger 21 and the lock spring 23 is connected to the other end of the lock plunger 21 and pulls the lock plunger 21 downward.

  The unlocking means 11 includes a lock release block 30 capable of mechanically restricting the elevating operation of the lock block 20, a lock release plunger 31 connected to the lock release block 30, and a power release lock release plunger 31 to the left. , And a lock release spring 32 that is set between the lock release solenoid 33 and the lock release block 30 and that pushes the lock release block 30 to the right.

  The lock forcible release means is combined with the lock release means, has a claw fitted in the groove 30A provided in the lock release block 30, and can rotate the lock release block 30 to the left by the claw by rotating. A lock forcible release rotation block 34, a lock forcible release rotation bar 34A attached to the center of the lock forcible release rotation block 34, penetrating outside the case 3 of the switch body, and having a key groove 34B at its end. The forced release key 4 is inserted into the key groove 34B and rotates the lock release rotation block 34 via the lock release rotation bar 34A.

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 by the circle 1 in FIG. 3, and the lock block 20 is locked by the lock spring 23 as shown in FIG. The lock release block 30 is pressed against the side surface of the lock block 20 by the operation 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. 2B, and a key insertion detection signal is sent to the control device.
Upon receiving the key insertion detection signal, the control device issues an energization command to the lock solenoid 22 (circle 2 in 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 (in the direction A), and is fitted into the lock groove 2A of the key 2 to lock the key 2. I do. When the lock block 20 moves up, the lock release spring 32 pushes the lock release block 30 rightward (in the direction C) and enters below the 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. 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 been completely stopped, first, the energization of the lock solenoid 22 is cut off (circle 3 in 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, but cannot descend because the lock release block 30 has entered the lower part of the lock block 20. At this stage, the key 2 is still in the locked state.

  Next, when an energizing command (circle 4 in FIG. 3) is issued to the unlocking solenoid 33, the unlocking block 30 moves leftward (in the direction D) against the unlocking spring 32, and the unlocking block 30 is moved. As a result, the lock block 20, which has been prevented from moving, becomes movable, descends (in the direction B), and the lock of the key 2 is released (FIG. 2D). Thereby, the safety door 6 becomes movable and can be opened. After that, the energization of the lock release solenoid 33 may be cut off as appropriate.

Next, a 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.
When the power is shut off in the state of FIG. 2C in which the key 2 is locked, the lock solenoid 22 is turned off (circle 1 in FIG. 4). For this reason, the lock block 20 tends to descend downward (direction B) by the action of the lock spring 23, but the lock block 20 can descend 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 (circle 2 in FIG. 4), the forcibly unlocked rotation bar 34A and the forcibly unlocked rotation block 34 rotate, and the claw of the forcibly unlocked rotation block 34 is rotated. As a result, the lock release block 30 is pushed leftward (D direction). By forcibly retracting the lock release block 30 to the left (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 a state in which 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 direction E, the lock release block 30 moves to the left (in the direction D). However, since the lock solenoid 22 is kept energized, the lock block 20 continues to lock the key 2 without descending. I'm going. That is, the lock cannot be forcibly released in the normal state.

In the above description, the key 2 is attached to the safety door and the key body 1 is attached to the fixed portion of the safety fence. However, 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 unit and the lock release unit described in the present embodiment are replaced with each other, the tip of the lock release block 30 of the lock release unit is inserted into the lock groove 2A of the key 2, and the lock block 20 of the lock unit is locked. It may be mounted below the release block 30. At this time, the unlocking means is combined with the unlocking 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 to the left, 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. A control circuit for energizing each solenoid thereafter can be easily set.
Also, instead of a solenoid that uses electric energy as it is, an actuator that uses fluid energy such as air or hydraulic pressure can be used.

FIG. 2 is a diagram showing an embodiment of the safety switch of the present invention. FIG. 4 is a diagram illustrating the operation of the safety switch according to the present embodiment. Diagram showing signal timing between devices during normal control Diagram showing inter-device signal timing (forced release) at power-off

Explanation of reference numerals

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 32 Lock Release spring 33 Lock release solenoid 34 Lock release rotation block 40 Key insertion detection switch

Claims (3)

It consists of a key member and a switch body, each of which is attached to either a safety fence or a safety door,
The key member has a fixing portion,
The switch body is
Locking means comprising: a fixing member engaged with the fixing portion of the key member; and a plunger which is movable in the longitudinal direction and presses the fixing member at one end by a solenoid or a spring.
Unlocking means comprising a plunger provided at one end with a restricting portion for restricting the movement of the plunger of the locking means and being movable in the longitudinal direction, the plunger being pressed toward the one end by a solenoid or a spring and pressing the restricting portion; ,
A lock-type safety switch comprising: a forced release unit that retracts the restricting unit from the plunger of the lock unit when the restricting unit restricts the plunger of the lock unit.   3. The lock-type safety switch according to claim 1, further comprising a forced release key for operating said forced release means.   3. The lock-type safety switch according to claim 1, wherein the key member is set at a predetermined position of the switch body, and a fixing member of the lock unit is engaged with a fixing portion of the key member. 4. A lock-type safety switch having a switch that detects the state when they are combined.

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