JP2005038664A - Lock door switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the man-hour of a user by eliminating the necessity of assembling an external circuit at the user side in preparation of the case that a switch is in disorder. <P>SOLUTION: Based on states of a first monitor contact which is switched in accordance with the insertion/pulling-out of a key between terminals 33, 34 and a second monitor contact which is switched in accordance with a locked/unlocked state between terminals 51, 52, an abnormal state that the key is pulled out and a door is opened in spite of the locked state is detected, and a relay contact of a latching relay 24 inserted between terminals 11, 42 in an output line for a safety circuit is held in an opened state. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic lock type lock door switch.
[0002]
[Prior art]
In general, a door switch detects the opening and closing of a door provided at the entrance / exit of a work area where an automated machine tool is installed, and turns the machine tool on and off. When the door is closed, the key provided on the door side is Inserted into the switch body provided on the entrance / exit side, the internal cam is rotated by the inserted key, the switching mechanism built in the switch body is switched to the switch-on state, the power circuit etc. are connected, and the door is opened When opened, the internal cam is rotated by pulling out the key, the switching mechanism is switched to the switch-off state, and the power supply circuit and the like are shut off (see, for example, Patent Document 1).
[0003]
Such a door switch is an electromagnetic lock type door switch, for example, the door is not locked immediately even when the door is closed, and the lock mechanism is operated only while the electromagnetic solenoid is energized to maintain the lock state. Solenoid lock type that supplies power to the machine tool from the power circuit in the locked state, stops energizing the electromagnetic solenoid, releases the lock to allow the door to open, and shuts off the power circuit It has been known.
[0004]
In such an electromagnetic lock type door switch, when the door is forcibly opened when the lock is not released, the internal cam is forced to rotate by pulling out the key. May rotate and the key may be pulled out to open the door.
[0005]
If the door is closed again with the lock mechanism broken in this way, the door will not be locked, but the switching mechanism will be switched on and the power supply circuit will be connected to operate the machine tool. The operator may continue to use the device without noticing it even though the lock does not work, and may cause an unexpected situation.
[0006]
[Patent Document 1]
JP 2002-50262 A
[0007]
[Problems to be solved by the invention]
For this reason, conventionally, among the plurality of contacts of the switching mechanism built in the switch body, it is different from the plurality of main contacts for opening and closing the power circuit in conjunction with the opening and closing of the door and the operation of the electromagnetic lock. Using the monitor contacts, on the user side, the opening and closing of the door and the operating state of the electromagnetic lock are monitored by an external circuit, and although the abnormal state as described above, that is, the electromagnetic lock is applied, the door is It is configured to detect an open state and take appropriate measures such as shutting off the power supply circuit or issuing an alarm.
[0008]
Thus, in preparation for a case where the switch fails, the user must assemble an external circuit by wiring from the monitor contact, and there is a problem that man-hours increase accordingly.
[0009]
The present invention has been made in view of the above points, and it is an object of the present invention to eliminate the need for a user to assemble an external circuit in preparation for a switch failure, and to reduce the number of man-hours for the user.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is configured as follows.
[0011]
That is, the lock door switch of the present invention includes a switching mechanism, an operation mechanism that operates forward and backward by inserting and removing a key to switch the first main contact of the switching mechanism, and the first main contact. Lock mechanism for locking in the contact switching state brought about by insertion of the lock, lock / unlock means for locking or unlocking by the lock mechanism, and switching operation according to lock / unlock by the lock / unlock means A lock door switch having a second main contact that includes a detection means for detecting and outputting an abnormality, and the first and second main contacts based on a detection output of the detection means Holding means for holding the main circuit line in an open state.
[0012]
Here, the main circuit refers to a main circuit to which the output of the lock door switch is given, for example, a power supply circuit or a safety circuit for controlling power supply interruption to the machine tool.
[0013]
According to the present invention, for example, when the lock mechanism is forcibly pulled out and the lock mechanism is destroyed and the lock door switch fails, the abnormality is detected and the line for the main circuit including the first and second main contacts is provided. Is maintained in the open state, so even if the key is inserted in the failed state, the line for the main circuit remains open. Will not turn on and the machine tool will not operate. This eliminates the need for the user to assemble an external circuit by wiring from the monitor contact in preparation for a switch failure, as in the conventional case.
[0014]
In one embodiment of the present invention, the detection means and the holding means are built in a switch case in which the mechanisms are housed.
[0015]
According to this embodiment, the lock door switch itself has a built-in configuration for detecting an abnormality and opening the line for the main circuit. There is no need for wiring and man-hours can be reduced.
[0016]
In a preferred embodiment of the present invention, the detection device includes a first monitor contact that is switched in response to the insertion / extraction of the key, and a second monitor contact that is switched in response to the lock / unlock. The means detects an abnormality of the lock mechanism based on an operating state of the both monitor contacts, and the main circuit is a safety circuit.
[0017]
According to this embodiment, the first monitor contact is used to monitor the insertion / removal of the key corresponding to the opening / closing of the door, and the lock / unlock is monitored using the second monitor contact. An abnormal state in which the key is removed, that is, an abnormal state in which the lock mechanism is broken, can be detected. When the lock mechanism is broken and fails, the output of the lock door switch to the safety circuit is opened. It can be kept in a state.
[0018]
In one embodiment of the present invention, the holding means is a latching relay that holds the contact provided on the line for the main circuit in an open state in response to the detection output.
[0019]
According to this embodiment, when the locking mechanism is broken, the contact of the latching relay interposed in the main circuit line can be held open.
[0020]
In a preferred embodiment of the present invention, the lock / unlock means includes an electromagnetic solenoid, and performs the lock when the electromagnetic solenoid is energized, and in a state where the key is inserted, When the electromagnetic solenoid is energized, release means for releasing the holding of the latching relay is provided.
[0021]
According to this embodiment, even if the abnormality of the lock mechanism is detected and the line for the main circuit is held in the open state, if the normal operation, that is, the key is inserted and the electromagnetic solenoid is excited and locked, the holding is not performed. For example, when a malfunction of the lock mechanism is detected but the lock mechanism has not been destroyed, the lock door switch is returned to normal operation again by performing a proper operation. Can be made.
[0022]
In one embodiment of the present invention, the power source for holding and releasing the latching relay is also used as the power source for the electromagnetic solenoid.
[0023]
According to this embodiment, when detecting an abnormality of the lock mechanism, it is not necessary to separately provide a power source for holding the main circuit line or releasing the holding, and the power source of the electromagnetic solenoid can be used as it is. become.
[0024]
In another embodiment of the present invention, a series circuit in which the first monitor contact, the second monitor contact, and the set coil of the latching relay are connected in series is connected in parallel to the electromagnetic solenoid. .
[0025]
According to this embodiment, in the locked state in which the electromagnetic solenoid is energized, when an abnormality occurs such as when the key is pulled out and the door is opened, both monitor contacts are turned on to apply a voltage to the set coil. The contact of the latching relay interposed in the circuit line can be kept open.
[0026]
In a preferred embodiment of the present invention, the release means includes a release relay and a charge / discharge circuit, and a coil of the release relay is connected in parallel to the electromagnetic solenoid, and the contact of the release relay and the latching A series circuit with a reset coil of the relay is connected in parallel with the electromagnetic solenoid, and the charge / discharge circuit is connected in parallel with the reset coil of the latching relay.
[0027]
According to this embodiment, when the electromagnetic solenoid is energized and locked, the release relay is energized and its contact is opened, but the charging / discharging circuit is charged using the time until the release, and this charging / discharging circuit is charged. Due to the discharge of the discharge circuit, the latching relay can be reset by energizing the reset coil of the latching relay parallel to the charge / discharge circuit, that is, the open state of the main circuit line can be released.
[0028]
In another embodiment of the present invention, the switching mechanism may be configured such that the movable member that supports the movable terminal facing the fixed terminal is biased and displaced by a return spring so that the movable terminal contacts the fixed terminal and The first main contact is turned on, and the movable member is displaced against the return spring, whereby the movable terminal is separated from the fixed terminal, and the first main contact is turned off. The operation mechanism displaces the movable member to the OFF position of the first main contact against the return biasing force when the key is pulled out, and moves the movable member by the return biasing force when the key is inserted. The lock mechanism is configured to engage the lock member with the movable member or a plunger interlocked with the movable member so that the first main contact is moved to the lock position. Status It is intended to, the locking member, when extracting the load state of the above set key of the lock acts, is destroyed in which the lock is released.
[0029]
According to this embodiment, when the key is forcibly extracted in the locked state and an extraction load more than the setting is applied to the lock member, the lock member is destroyed and the lock is released. For example, the rotary cam or the plunger is destroyed. As described above, the portion to be destroyed and the strength of the destruction do not vary, and can be easily restored by replacing the lock member.
[0030]
In a preferred embodiment of the present invention, the lock member is made of a brittle material and has a portion that is easily deformed and damaged by the extraction load.
[0031]
As the brittle material, for example, ceramics are preferable, and as the portion that is easily deformed and damaged, for example, a groove formed around the engaging portion is preferable.
[0032]
According to this embodiment, since the lock member is made of a brittle material such as ceramics that hardly undergoes plastic deformation until breakage, variation in fracture strength at which the lock member is broken can be suppressed, and stress such as a groove is concentrated. Thus, since it has a portion that is easily deformed and damaged, it is always destroyed at this portion, and the design of the breaking strength is facilitated.
[0033]
In another embodiment of the present invention, the lock member has a protrusion on a contact surface with the plunger.
[0034]
According to this embodiment, even if the plunger is tilted slightly and acts on the lock member, it will surely come into contact with the projection portion, and the contact portion will not vary, thereby further reducing variation in breaking strength. it can.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0036]
As shown in FIG. 1, this lock door switch is used by being attached to an entrance / exit of an automatic machining area where a machine tool is installed, and is a switch body with an interlock attached to a fixed frame of the entrance / exit. 1, and a key 2 attached to a door to be opened and closed is inserted into and removed from the switch body 1. The key 2 may be attached to the fixed frame, and the switch body 1 may be attached to the door.
[0037]
The switch main body 1 includes a main body case 3 and a head case 4 screwed to the upper left end of the main body case 3 as a switch case. A key insertion slot 5 is formed in the head case 4.
[0038]
2 to 4 are schematic views showing the internal configuration of the lock door switch of FIG. 1, FIG. 2 shows the state before the key 2 is inserted, FIG. 3 shows the inserted state of the key 2, and FIG. Each state is shown.
[0039]
The main body case 3 incorporates a main switching mechanism 6, a lock mechanism 7, an electromagnetic solenoid 8 constituting a main part of the lock / unlock means, a lock / unlock monitoring switching mechanism 9, and a circuit board 10 described later. Further, the head case 4 incorporates a rotating cam 11 as an operation mechanism for operating the switching mechanism 6.
[0040]
The switching mechanism 6 is arranged on the left side in the main body case 3 so as to be positioned directly below the head case 4 and can move up and down with three pairs of first to third fixed terminals 12-1 to 12-3. The movable member 13 includes three movable terminals 14-1 to 14-3 supported by the movable member 13, and the movable member 13 is biased upward by a return spring 15. Further, each of the movable terminals 14-1 to 14-3 is elastically supported so as to be able to move backwardly through a stroke absorbing spring (not shown).
[0041]
In this embodiment, two contacts that are switched by inserting and removing the key 2 are provided, and the first and second fixed terminals 12-1 and 12-2 and the first and second movable terminals 14-1 are provided. , 14-2 constitute two contact points.
[0042]
In this embodiment, of the two contacts, a first main contact connected to a main circuit such as a safety circuit is constituted by the first fixed terminal 12-1 and the first movable terminal 14-1. .
[0043]
Further, a first monitor contact that is switched in response to the insertion / extraction of the key 2 is provided, and the first monitor contact is constituted by the third fixed terminal 12-3 and the third movable terminal 14-3. Is done.
[0044]
A plunger 16 is in contact with the upper end of the movable member 13, and the upper end of the plunger 16 is inserted into the head case 4 and is in contact with the outer peripheral cam surface of the rotary cam 11.
[0045]
A rotating cam 11 as an operation mechanism incorporated in the head case 4 is supported so as to be rotatable around a horizontal axis, and the outer shape of the rotating cam 11 is reversed in accordance with the insertion / extraction of the key 2 into / from the key insertion port 5. It is made into the shape which is rotated and operated.
[0046]
As shown in FIG. 2, when the key 2 is extracted, the movable member 13 is displaced downward by the plunger 16 being pushed down against the return spring 15 by the large-diameter cam portion 11a of the rotating cam 11. Then, a switch-off state which will be described later appears, and as shown in FIG. 3, when the key 2 is inserted and the rotating cam 11 is rotated clockwise in the figure, the plunger 16 has a small diameter of the rotating cam 11. The cam member 11b engages and can be displaced upward, and the movable member 13 is biased upward and a switch-on state described later appears.
[0047]
As described above, the movable member 13 is forcibly pushed down by the rotating cam 11 to be switched off, so that the contact can be forcibly separated even if welding occurs.
[0048]
In addition, you may comprise the movable member 13 and the plunger 16 by one member.
[0049]
FIG. 2 shows a switch-off state in which the movable member 13 moves downward against the return spring 15 and the two contacts including the first main contact are turned off. The first and first components constituting the two contacts are shown in FIG. The second movable terminals 14-1 and 14-2 are separated from the first and second fixed terminals 12-1 and 12-2, and at this time, the third movable terminal constituting the first monitor contact 14-3 is conductively connected to the third fixed terminal 12-3.
[0050]
Further, as shown in FIG. 3, the key 2 is inserted and the movable member 13 is urged and moved upward by the return spring 15, so that the first and first contacts that constitute two contacts including the first main contact are formed. The two movable terminals 14-1 and 14-2 are brought into contact with the first and second fixed terminals 12-1 and 12-2 to be switched on. At this time, the first monitor contact is formed. The third movable terminal 14-3 to be separated is away from the third fixed terminal 12-3.
[0051]
The lock mechanism 7 is of a solenoid lock type, and includes a lock member 17 that acts on the lower portion of the plunger 16, a lever 18 that slides and moves left and right along a guide groove formed inside the main body case 3, and this lever The above-described electromagnetic solenoid 8 connected to 18 and the like are configured. When the electromagnetic solenoid 8 is excited and the core 8a is displaced upward, the lock member 17 is slid to the left which is the lock direction. As shown in FIG. 4, when the lock is applied and the excitation is released, the lock member 17 is slid to the right in the unlocking direction and unlocked by a spring (not shown). .
[0052]
The lever 18 is connected to the movable member 19 of the monitoring switching mechanism 9, and as shown in FIGS. 2 and 3, when the lever 18 is in the unlocked position, The two first and second movable terminals 21-1 and 21-2 held by the movable member 19 with respect to the two pairs of first and second fixed terminals 20-1 and 20-2 are separated from each other, As shown in FIG. 4, when the movable member 19 is in the locked position, the movable terminals 21-1 and 21-2 are brought into contact with the fixed terminals 20-1 and 20-2, respectively. Yes.
[0053]
In this embodiment, there are two contacts that are switched in accordance with locking / unlocking by the electromagnetic solenoid 8, and the first and second fixed terminals 20-1, 20-2 and the first, first, Two movable terminals 21-1 and 21-2 constitute two contact points.
[0054]
In this embodiment, of the two contacts, the second main contact connected to the main circuit such as a safety circuit is constituted by the first fixed terminal 20-1 and the first movable terminal 21-1. .
[0055]
Further, the second monitor contact that is switched in accordance with the lock / unlock is constituted by the second fixed terminal 20-2 and the second movable terminal 21-2.
[0056]
5A and 5B are plan views of the lock member 17, in which FIG. 5A shows a state before the lock shown in FIG. 3, and FIG. 5B shows a lock state shown in FIG.
[0057]
An engagement portion 22 that engages with the plunger 16 is formed on the left side of the lock member 17 so as to be bridged back and forth, and a step is formed on the lower side of the plunger 16 on the left side of the engagement portion 22. A concave portion 22a that engages with the small-diameter portion formed in a shape from the right side is formed. In addition, a projection 22b that contacts the plunger 16 is formed at the center near the recess 22a as described later, and a groove 22c is formed at both ends of the engagement portion 22.
[0058]
The lock member 17 has operation pin portions 23a and 23b formed on the front and rear sides of the right end portion thereof, and the lever 18 is engaged and linked to the operation pin portion 23a on the back side.
[0059]
In the switch-off state of FIG. 2 in which the key 2 is extracted, the electromagnetic solenoid 8 is in a non-energized state, the lock member 17 is slid to the right in the figure, and the lock member 17 is engaged with the plunger 16. Without movement, the plunger 16 is allowed to move.
[0060]
When the rotary cam 11 is rotated by the insertion of the key 2 and the plunger 116 and the movable member 13 are displaced upward to be switched on, the small diameter portion of the plunger 16 is locked as shown in FIGS. It reaches the position facing the member 17.
[0061]
In this state, when the electromagnetic solenoid 8 is energized, the lock member 17 slides and displaces to the left in the drawing via the lever 18, and as shown in FIG. 4 and FIG. 22a engages with the small diameter portion of the plunger 16 to provide a locked state. In this locked state, the tip of the engaging portion 22 comes into contact with the upper end step portion of the small diameter portion of the plunger 16 from below, so that the downward displacement of the plunger 16 is prevented and the reverse rotation of the rotary cam 11, that is, the key Extraction of 2 is prevented.
[0062]
In this embodiment, when the key 2 is forcibly pulled out in the locked state, the parts to be broken are divided into parts such as the rotating cam 11, the plunger 16, or the head case 4. In order to prevent the strength from varying, the following configuration is adopted.
[0063]
In other words, in this embodiment, the lock member 17 is made of a brittle material, for example, ceramics, and at the both ends of the engaging portion 22 so as to be broken when an extraction load more than a set value is applied in the locked state. The groove 22c is formed as described above.
[0064]
As a result, the key 2 is forcibly pulled out and engaged in the locked state in which the upper end step portion of the small diameter portion of the plunger 16 abuts against the engaging portion 22 of the lock member 17 to prevent downward displacement of the plunger 16. When the upper end step portion of the plunger 16 is applied to the joint portion 22 with a pressing load equal to or higher than the setting, the groove portion 22c of the engaging portion 22 is damaged and falls off.
[0065]
Therefore, there is no variation in the portion to be broken and its breaking strength, and it can be restored relatively easily by replacing the lock member 17.
[0066]
In addition, since the ceramic material has little change in mechanical characteristics even when the usage environment such as temperature changes, it is possible to suppress variation in fracture strength even if the usage environment changes.
[0067]
Further, in this embodiment, the plunger 16 of the engagement portion 22 is also reduced in order to reduce the variation in breaking strength even when the key insertion port of the head case 4 is changed to change the extraction direction of the key 2. As described above, the protrusion 22b is formed on the contact surface with respect to the surface.
[0068]
That is, when the key 2 is forcibly extracted, the plunger 16 pushed down by the rotation of the rotary cam 11 is slightly inclined and comes into contact with the engaging portion 22 of the lock member 17 so that a so-called one-sided state is obtained. The contact position changes depending on the direction of extracting the key. That is, the load point acting on the engaging portion 22 changes depending on the direction in which the key is pulled out, and the breaking load varies.
[0069]
Therefore, in this embodiment, the protrusion 22b is formed on the engaging portion 22 as described above, so that the plunger 16 always comes into contact with the protrusion 22b regardless of the direction in which the key 2 is pulled out. The load acting on the engaging portion 22 is not varied.
[0070]
Referring to FIG. 4 again, when the electromagnetic solenoid 8 is energized in the switch-on state and the lock member 17 of the lock mechanism 7 moves forward to the normal locking position, the monitoring switching mechanism 9 is also switched on. The pair of first fixed terminals 20-1 constituting the second main contact of the monitoring switching mechanism 9 is changed to the pair of first fixed terminals 12-1 constituting the first main contact in the switching mechanism 6. When the series circuit is closed and connected, the power to the machine tool in the automatic machine area is turned on via the safety circuit as the main circuit to which the output of the lock door switch is given. It is supposed to be.
[0071]
When the key 2 is pulled out, the energization of the electromagnetic solenoid 8 is released and the core 8a is displaced downward, so that the lock member 17 is slid to the right via the lever 18 and the tip of the engaging portion 22 is moved to the plunger. The plunger 16 is unlocked by being detached from the 16 small diameter portion. As a result, the key 2 can be removed, that is, the door can be opened.
[0072]
In this embodiment, when the door is forcibly opened without releasing the lock and the lock member 17 of the lock mechanism 7 is broken, the operator continues to use the device without noticing it and the unexpected situation occurs. It is configured as follows so as not to bring
[0073]
FIG. 6 is an internal circuit diagram showing the main part of this embodiment, showing a state in which the key 2 is inserted and locked, and portions corresponding to the above-mentioned terminals are denoted by the same reference numerals. Is attached.
[0074]
Here, for convenience of explanation, each pair of the first and second fixed terminals 12-1 and 12-2 constituting the two contacts including the first main contact of the switching mechanism 6 is connected to the terminals 11 and 12 and the terminals. The pair of third fixed terminals 12-3, which are referred to as 21 and 22 and constitute the first monitor contact, are referred to as terminals 33 and 34.
[0075]
Each pair of the first and second fixed terminals 20-1 and 20-2 constituting the second main contact and the second monitor contact of the monitoring switching mechanism 9 is connected to terminals 41 and 42 and a terminal 51, respectively. , 52.
[0076]
Usually, the terminals 11 and 12 and the terminals 41 and 42 are connected in series, and further connected to an external safety circuit. In the safety circuit, the doors are closed and the terminals 11 and 12 are turned on, and the electromagnetic solenoid 8 is energized through the power terminals E1 and E2 to be locked and the terminals 41 and 42 are turned on. The power circuit is turned on to allow the machine tool to be operated. Conversely, when the door is open or not locked, that is, when the terminals 11 and 42 are off, the safety circuit is The power supply circuit for the machine tool is cut off to prohibit the operation of the machine tool.
[0077]
In this embodiment, when the abnormality occurs such that the lock mechanism 7 is broken by forcibly opening the door without releasing the lock, this is detected and the terminals 11 and 42 that are output lines to the safety circuit are opened. The machine tool is configured to be held in the (open) state, so that the machine tool is not operated even if the operator uses it without noticing that the lock mechanism 7 is broken.
[0078]
That is, in this embodiment, the terminals 33 and 34 constituting the first monitor contact for monitoring the insertion and removal of the key 2, that is, the opening and closing of the door, and the terminals constituting the second monitor contact for monitoring the lock / unlock. 51 and 52 are connected in series, and the relay contact interposed between the terminals 12 and 41 is held in the OFF state when the door is opened, although the lock is applied based on the operation state. A latching relay 24 is provided.
[0079]
In this embodiment, the terminals 33 and 34 and the terminals 51 and 52 are connected in series to constitute an abnormality detection means, and based on the output of the abnormality detection means, the latching relay 24 as a holding means causes the terminals 12, The line between 41 is held in an off (open) state.
[0080]
FIG. 7 is a circuit diagram showing a detailed configuration of the main part of FIG. 6, and corresponding portions are denoted by the same reference numerals.
[0081]
First, when the door is closed and the key 2 is inserted, the terminals 11 and 12 are turned on, and the relay contact 25 of the latching relay 24 interposed between the terminals 12 and 41 is also turned on. Yes.
[0082]
In this state, when the electromagnetic solenoid 8 is energized via the power supply terminals E1 and E2, the locked state is established, the terminals 41 and 42 in FIG. 6 are turned on, and the external safety circuit is connected to the machine tool from the power supply circuit. The machine tool is allowed to operate with the supply of power.
[0083]
In this locked state, when the door is forcibly opened without releasing the lock, the terminals 33 and 34 are turned on. At this time, the second monitor between the terminals 51 and 52 remains in the locked state. The contact is also kept on, so that a voltage is applied to the set coil (R (S)) of the latching relay 24 via the jumper wire 26 shown in FIG. The relay contact 25 of the latching relay 24 is turned off and held in that state. Therefore, the terminals 11 and 42, which are output lines for the safety circuit, are held in an open state, and even if the operator closes the door again without noticing that the lock mechanism 7 has been destroyed. The machine will not operate.
[0084]
In this way, when the door is opened in the locked state and the lock mechanism 7 is broken, the output line is held in the open state. Thus, it is not necessary to build an external circuit for taking appropriate measures such as shutting off the power supply circuit for the machine tool, and the man-hours on the user side are reduced accordingly.
[0085]
Further, in this embodiment, the door is forcibly opened without releasing the lock, the latching relay 24 is set, and the terminals 11 and 42 that are output lines to the safety circuit are held in the open state. In other words, when the electromagnetic solenoid 8 is energized and locked after the door is closed, a release relay 27 is provided so that the latching relay 24 can be reset. A discharge circuit is provided. Thus, a voltage is applied to the reset coil (R (R)) of the latching relay 24 every time the electromagnetic solenoid 8 is energized with the door closed.
[0086]
That is, when the electromagnetic solenoid 8 is energized, the relay 27 is also energized, and the relay contact 30 of the relay 27 is turned off with a slight time delay, for example, about 2 msec. During this time delay, the capacitor 29 is charged via the resistor 28, and the voltage is applied to the reset coil (R (R)) of the latching relay 24 by using the discharge of the capacitor 29 so as to be reset. Yes.
[0087]
The relay 27, the resistor 28, the capacitor 29, the latching relay 24, and the like are mounted on the circuit board 10 described above.
[0088]
FIG. 8 is a time chart for explaining the above operation. In FIG. 8, (a) is the opening and closing of the door, (b) the energization state for the electromagnetic solenoid 8, (c) is the reset signal, and (d) is the abnormality detection. The output (set signal), (e) shows the latch output, and (f) shows the state between the terminals 11 and 42, respectively.
[0089]
First, when the door is closed and the electromagnetic solenoid 8 is energized and locked, the terminals 11 and 42, which are output lines to the safety circuit, are turned on, and power is supplied to the machine tool via the safety circuit to allow the machine tool to work. The machine will operate. When the door is closed and the electromagnetic solenoid 8 is energized and locked, a reset signal is output.
[0090]
Next, in this state, as shown in FIG. 5B, when the energization of the electromagnetic solenoid 8 is stopped and the lock is released (unlocked), the terminals 11 and 42 which are output lines to the safety circuit are turned off. Then, the supply of power to the machine tool is cut off via the safety circuit, and the operation of the machine tool is stopped. With this unlocked state, the door can be opened as shown in FIG.
[0091]
Next, the door is closed again and the electromagnetic solenoid 8 is energized to be in a locked state, the terminals 11 and 42 which are output lines to the safety circuit are turned on, and power is supplied to the machine tool via the safety circuit. Start the machine.
[0092]
In this locked state, if the door is forcibly opened at time T1 without releasing the lock, the terminals 33 and 52 are turned on, the latching relay 24 is set, the relay contact 25 is turned off, and the output to the safety circuit The terminals 11 and 42 which are lines are turned off (opened), the supply of power to the machine tool is cut off via the safety circuit, and the operation of the machine tool is stopped.
[0093]
Thereafter, regardless of whether the door is opened or closed, or the energization of the electromagnetic solenoid 8 is stopped, the terminals 11 and 42 as output lines are held in the OFF state.
[0094]
Next, when the normal operation, that is, when the door is closed and the electronic solenoid 8 is energized, the latching relay 24 is reset by the reset signal, and the terminals 11 and 42 which are output lines to the safety circuit are turned on, and the safety circuit is turned on. The machine tool can be operated by supplying power to the machine tool via the.
[0095]
As another embodiment of the present invention, the reset signal may be omitted.
[0096]
In the embodiment described above, the lock member 17 is made of ceramics, but may be made of other materials such as PPS (polyphenylene sulfide resin).
[0097]
In the above-described embodiment, the lock member 17 is easily damaged by forming the groove 22c. However, the lock member 17 is not limited to the groove, and may be easily damaged by forming a notch or a slit.
[0098]
In the above-described embodiment, the description is applied to the solenoid lock type switch. However, by providing the latching relay power source separately from the electromagnetic solenoid power source, the door is locked when the door is closed. The present invention can be similarly applied to a mechanical lock type switch in which the lock is released only when the power is turned on.
[0099]
【The invention's effect】
As described above, according to the present invention, when the lock key is forcibly removed and the lock mechanism is broken and the switch is broken, this is detected and the main circuit line is held open. Therefore, even if the door is closed, the power supply circuit of the machine tool is not turned on and the machine tool does not operate. Therefore, as in the past, the user must wire from the monitor contact in preparation for a switch failure. This eliminates the need for an external circuit and reduces the man-hours on the user side.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an overall appearance of a lock door switch.
FIG. 2 is a schematic diagram showing an internal configuration before insertion of a key 2;
FIG. 3 is a perspective view showing an internal configuration of a key 2 in an inserted state.
FIG. 4 is a perspective view showing an internal configuration in a state where the key 2 is inserted and locked.
FIG. 5 is a plan view of a lock member.
6 is an internal circuit diagram of the embodiment of FIG. 1;
7 is a circuit diagram showing a detailed configuration of a main part of FIG. 6;
FIG. 8 is a time chart for explaining operations;
[Explanation of symbols]
2 key 3 body case 6 switching mechanism
7 Locking mechanism 8 Electromagnetic solenoid 13 Movable member
16 Plunger 17 Lock member 22 Engagement part

Claims (12)

A switching mechanism, an operating mechanism that operates forward and backward by inserting and removing a key to switch the first main contact of the switching mechanism, and the first main contact is locked in a contact switching state brought about by the insertion of a key A lock mechanism for locking, a lock / unlock means for locking or unlocking by the lock mechanism, and a second main contact that is switched according to the lock / unlock by the lock / unlock means Lock door switch,
Detection means for detecting and outputting an abnormality,
Based on the detection output of the detection means, holding means for holding the main circuit line including the first and second main contacts in an open state;
A lock door switch comprising: The lock door switch according to claim 1, wherein the detection unit and the holding unit are built in a switch case in which the mechanisms are housed. A first monitor contact that is switched according to the insertion / extraction of the key, and a second monitor contact that is switched according to the lock / unlock;
The detection means detects an abnormality of the lock mechanism based on the operating state of the monitor contacts.
The lock door switch according to claim 1 or 2, wherein the main circuit is a safety circuit. The lock door switch according to any one of claims 1 to 3, wherein the holding means is a latching relay that holds a contact provided in the main circuit line in an open state in response to the detection output. The lock / unlock means includes an electromagnetic solenoid, and performs the locking when the electromagnetic solenoid is energized.
The lock door switch according to claim 4, further comprising release means for releasing the holding of the latching relay when the electromagnetic solenoid is energized in a state where the key is inserted. The lock door switch according to claim 5, wherein a power source for holding and releasing the latching relay is also used as a power source for the electromagnetic solenoid. The lock door switch according to claim 6, wherein a series circuit in which the first monitor contact, the second monitor contact, and the set coil of the latching relay are connected in series is connected in parallel to the electromagnetic solenoid. The release means includes a release relay and a charge / discharge circuit, the release relay coil is connected in parallel to the electromagnetic solenoid, and a series circuit of a contact of the release relay and a reset coil of the latching relay is provided. The lock door switch according to claim 7, wherein the lock door switch is connected in parallel to the electromagnetic solenoid, and the charge / discharge circuit is connected in parallel to a reset coil of the latching relay. In the switching mechanism, the movable member supporting the movable terminal facing the fixed terminal is biased and displaced by a return spring, so that the movable terminal contacts the fixed terminal, and the first main contact is turned on. When the movable member is displaced against the return spring, the movable terminal is separated from the fixed terminal, and the first main contact is turned off.
The operation mechanism displaces the movable member to the off position of the first main contact against the return biasing force in the key extraction state, and in the key insertion state, the movable member is moved to the first biasing force by the return biasing force. The displacement of the main contact is turned on.
The lock mechanism is configured to engage the lock member with the movable member or a plunger interlocked with the movable member to bring the first main contact into the locked state. The lock door switch according to any one of claims 1 to 8, wherein the lock door switch is broken and unlocked when an extraction load exceeding a set value is applied to the key in a state. The lock door switch according to claim 9, wherein the lock member is made of a brittle material and has a portion that is easily deformed and damaged by the extraction load. The lock door switch according to claim 10, wherein the brittle material is ceramic, and the portion that is easily deformed and damaged is a groove formed around the engagement portion. The lock door switch according to claim 10 or 11, wherein the lock member has a protrusion on a contact surface with the plunger.

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