The present invention relates to a safety holder attached to a safety switch that is attached to a wall surface of a doorway and the like of a room installed with industrial machines and stops power supply to the industrial machines or the like when the door of the doorway is open. More specifically, the present invention relates to a safety holder that is attached to a safety switch with a door of a doorway being opened and prevents rotation of a drive cam and insertion of an actuator in the safety switch.
Rooms and factories installed with industrial machines or dangerous zones around the industrial machines themselves require installation of systems for locking the machines when doors of the doorway of the room and dangerous zones are not completely closed, for the purpose of preventing occurrence of troubles such as worker injury caused by the worker being caught in the machines. In order to meet such a requirement, a safety switch (Japanese Unexamined Patent Application Publication No. 10-69831) has been proposed. The safety switch is configured as follows. A switch body of the safety switch is installed on wall surfaces in the vicinity of the doorway of the room. When the door of the doorway is closed, a dedicated actuator fixed to the door is inserted into an insertion opening of the switch body. The insertion leads to rotation of a drive cam in the switch body. An operating rod moves in response to the rotation of the drive cam so that the connection state of a contact point is switched. Such a switching operation of the contact point allows a circuit connection to be switched to a main circuit (a power supply circuit for the industrial machines) side so that the machines in the room become operable state.
However, such a safety switch has a following drawback. In the cases where a worker enters the room for maintenance or the like of the machines while keeping the machines stopped and where another worker, who does not know the fact that the maintenance is being carried out, closes the door, the machines could be started and the worker already in the room could fall into a dangerous situation.
Therefore, in order to prevent the occurrence of the above situation or the like and further to ensure safety of workers, the safety holder shown in
However, the above-described prior art has the following problems.
(1) Both the base body 51 and the slide body 52 are merely inserted in the same one actuator insertion opening 54 and, therefore, the attaching state of the safety holder 50 with respect to the safety switch is not strong. Accordingly, there is a possibility that the safety holder 50 slips out from the actuator insertion opening 54 when the safety holder is pried open or the actuator is inserted in the other actuator insertion openings 58.
(2) In addition, since the lock mounting openings 55 and 56 in the base body 51 and the slide body 52 are arranged in alignment, a state occurs in which respective lock mounting openings 55 and 56 of the base body 51 and the slide body 52 overlap in the middle of insertion of the slide body 52 and before the slide body 52 being inserted all the way into the opening 54. Therefore, there is a possibility that the padlocks 57 are unintentionally locked in the lock mounting openings 55 and 56 in this state. In such a case, since the slide body 52 is not sufficiently inserted all the way, the attaching state of the safety holder 50 to the safety switch is not firm. Accordingly, when the actuator is inserted in the other actuator insertion opening 58, the driving cam rotates and the machine operates.
(3) Also, since both the base body 51 and the slide body 52 are inserted in the same one actuator insertion opening 54, the other actuator insertion opening 58 is not blocked. As a result, there is a possibility that the drive cam rotates when an actuator is forced to be inserted in the other actuator insertion opening 58.
As described above, the safety holder 50 of the prior art has not been adequate in view of safety of workers.
The present invention has been accomplished in view of the above-described circumstances, and it is an object of the present invention to provide a safety holder that blocks all of actuator insertion openings and firmly attaches to a safety switch, thereby enhancing safety of a worker.
In order to achieve the above-described view, the invention provides a safety holder for preventing insertion of an actuator into a safety switch, the safety switch including a switch body having a box-shaped body and actuator insertion openings provided in two different surfaces thereof through which the actuator is insertable, and a contacting portion provided within the switch body, connection of which is switched in response to insertion of the actuator. The safety holder is characterized by comprising a base body that engages with one of the actuator insertion openings provided in the two different surfaces and blocks the one of the actuator insertion openings, and a slide body movably attached to the base body so as to be able to block, when the base body is engaged with the one of the actuator insertion openings, the other one of the actuator insertion openings provided in the two different surfaces by engaging with the other actuator insertion opening.
According to the above configuration, both one of the actuator insertion openings and the other actuator insertion opening are blocked. As such, by blocking all of the actuator insertion openings, the situation found in the prior art in which the safety holder is slipped out from the actuator insertion opening due to the actuator being unintentionally inserted, can be completely prevented from occurring. Consequently, a safety holder with enhanced worker safety can be realized.
In the meantime, it is sufficient in the present invention that the slide body is movable with respect to the base body, and the slide body may or may not be configured rotatably with respect to the base body.
In the present invention, a key hole that is formed by the base body and the slide body and for fixing the slide body may emerge only when the slide body is moved to a predetermined position at which the slide body blocks the other actuator insertion opening.
According to the above configuration, locking can be prevented when the slide body is in the middle of insertion, since the key hole does not emerge.
In the present invention, the slide body may be movably and rotatably attached to the base body, and the base body may be provided with a rotation limiting means for limiting rotation of the slide body when the slide body is pulled out.
As described above, since the rotation of the slide body is limited when the slide body is pulled out, there is an advantage that the safety holder is easy to use.
In addition, in the present invention, a tip end portion of the slide body may engage with a tip end portion of the base body engaging with the one of the actuator insertion openings when the slide body is engaged with the other actuator insertion opening.
According to the above configuration, since the tip end portion of the slide body engages with the tip end portion of the base body engaging with one of the actuator insertion openings with the slide body being engaged with the other actuator insertion opening, attaching state of the safety holder with respect to the safety switch body becomes much stronger comparing to an example of the prior art.
In addition, in the present invention, the tip end portion of the base body inserted into the one of the actuator insertion openings may be fitted into a concave portion of a drive cam provided within the switch body to thereby limit rotation of the drive cam.
As described above, by limiting the rotation of the drive cam, safety of the worker becomes further ensured.
According to the present invention, the following advantage may be obtained.
Both the one of actuator insertion openings and the other actuator insertion opening are blocked. By blocking all of the actuator insertion openings like this, the situation found in the prior art, in which the safety holder is slipped out from the actuator insertion openings due to the actuator being unintentionally inserted, can be completely prevented from occurring. As a result of this, a safety holder with safety of a worker being enhanced is realized.
Hereinafter, a safety holder according to the present invention will be described in detail by way of embodiments. However, the present invention is not limited to the following embodiments.
Now, general configuration of a safety switch for which a safety holder of the present invention is used will be described with reference to
The switch body 2 is constituted with an operating portion 5 in which the actuator 3 is inserted and a switch portion 6 in which a contact block (not shown) is embedded. The operating portion 5 is provided with actuator insertion openings 7 and 8 on its two different surfaces such that the insertion direction of the actuator can be selected according to the condition of an installation location. The operating portion 5 is also provided with a drive cam 9 as apparently shown in
In the safety switch configured as above, when the actuator 3 proceeds to the inside of the operating portion 5 through the actuator insertion opening 7 and a pressing piece 3a of the actuator 3 (refer to
Next, when the actuator 3 is pulled out from this state, the drive cam 9 rotates in the direction opposite to the aforementioned direction due to backward movement of the actuator 3. In response to the rotation, the operating rod 10 moves to the connection contact point side of the switch portion 6. Then the connection contact point is switched to turn off the power supply to the machines.
In another embodiment, when the actuator 3 proceeds to the inside of the operating portion 5 through the other actuator insertion opening 8, the pressing piece 3a of the actuator 3 hits the drive cam 9 to rotate the drive cam 9. In response to the rotation of this drive cam 9, the operating rod 10 of the switch portion 6 moves to the side of the drive cam 9 of the operating portion 5 and the connection contact point is switched. At the same time, the pressing piece 3a of the actuator 3 fits into the concave portion 13 of the drive cam 9 (refer to
In the safety switch configured as above, when a worker enters the room for maintenance or the like of machines, the stopped state of the machines is maintained as long as the door 4 is kept opened. Therefore, safety of the worker is ensured. However, when the door 4 is closed by mistake, the machines are started, and the worker in the room could fall into a dangerous situation. To prevent such an accident from being occurred and ensure safety of a worker, the safety holder according to the present invention is used.
A safety holder 20 is constituted with a base body 21 and a slide body 22. The base body 21 and the slide body 22 are, for example, plate shaped members made of metal. Also, the base body 21 and the slide body 22 may be members made of rigid synthetic resin. The slide body 22 is formed with a guide opening 23 extending in a longitudinal direction (corresponding to insertion direction X shown in
As shown in
The elevating portion 21b is formed with an opening 35 through which insertion arms 34 (refer to
On the other hand, as shown in
Furthermore, the relative location between the lock mounting openings 40a and 40b and the lock mounting opening 40c is similar to that between the lock mounting openings 30a and 30b and the lock mounting opening 40c described above, and the lock mounting openings 40a and 40b and the lock mounting opening 40c deviate each other in the width direction (corresponding to the direction perpendicular to the insertion direction X). Accordingly, in the middle of insertion of the slide body 22, only part of the lock mounting opening 30a and the lock mounting opening 40c overlap, and also only part of the lock mounting opening 30b and the lock mounting opening 40c overlap. As the result, the padlock 45 cannot be locked via the lock mounting opening 30a and the lock mounting opening 40c, and also the padlock 45 cannot be locked via the lock mounting opening 30b and the lock mounting opening 40c.
In this example, the lock mounting openings 30c and 40c are oval; however, they may be circular lock mounting openings like the lock mounting openings 30a and 30b, and 40a and 40b. However, such a case also requires that the locations of lock mounting openings are deviated from the lock mounting openings 30a and 30b, 40a and 40b. That is, it is required that, when a plurality of lock mounting openings are provided along the insertion direction X, respective lock mounting openings are not arranged in alignment but are deviated in the direction perpendicular to the insertion direction X (width direction). This allows the lock of the padlocks through wrong openings to be prevented.
Furthermore, the insertion arms 34 of the slide body 22 is inserted in the opening 35 of the base body 21 and the tip end portion of the insertion arms 34 is kept inserted in the opening 35, as shown in
How to use the safety holder 20 having the above-described configuration will be described with reference to these drawings.
Firstly, as shown in
In such a state in which the insertion arms 34 enter the engagement hole 36 of the hanging portion 21d, the lock mounting opening 30a and the lock mounting opening 40a, the lock mounting opening 30b and the lock mounting opening 40b, and the lock mounting opening 30c and the lock mounting opening 40c are exactly overlapped, respectively. Therefore, a key hole 100 for fixing the slide body 22 with respect to the base body 21 is configured (refer to
As described above, since the safety holder 20 of the above configuration blocks the actuator insertion openings 7 and 8, the situation in which the drive cam 9 is rotated due to insertion of the actuator can be completely prevented from occurring. Also, since the engaging state can be obtained when the insertion arms 34 enter the engagement hole of the hanging portion 21d, the attaching state of the safety holder with respect to the safety switch body becomes much stronger than that of the safety holder of the prior art.
(1) In the above embodiment, the slide body 22 is movable in insertion direction X with respect to the base body 21, and rotatable around the connecting shaft 25. However, the configuration may be such that the slide body 22 is movable in the insertion direction X, but not rotatable.
(2) In the above embodiment, the configuration is such that the insertion arms 34 enter the engagement hole 36 and the attaching state can be obtained. However, notches into which the insertion arms 34 are fixed may be used in place of the engagement hole.
(3) In the above embodiment, a padlock is exemplified as a lock; however, a latch, pin, and so forth can be used instead of a padlock. In short, anything can be used as long as it can limit the movement of the slide body by connecting the base body and the slide body.
(4) In the above embodiment, one actuator insertion opening 7 is provided in the upper surface of the switch body 3. However, the safety holder of the present invention can be applied to a safety switch having a configuration in which an actuator insertion opening for rotating the drive cam 9 in the opposite direction is disposed on front side of the actuator insertion opening 7. In the safety switch having such a configuration, an effect of blocking all of the actuator insertion openings can be obtained, because, when the hanging portion 21d of the base body 21 is inserted in the actuator insertion opening 7, the second flat portion 21c of the base body 21 covers the actuator insertion opening for rotating in the opposite direction.
(5) In the above embodiment, in order to lock the padlock 45 (
The present invention can be suitably implemented on a safety holder of a safety switch.
Number | Date | Country | Kind |
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2005-256362 | Sep 2005 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2006/317475 | 9/4/2006 | WO | 00 | 11/10/2008 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2007/029656 | 3/15/2007 | WO | A |
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Number | Date | Country |
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4029344 | Feb 1991 | DE |
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Number | Date | Country | |
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20090321227 A1 | Dec 2009 | US |