JP2001273836A - Door switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safer door switch which prevents the possibility of detecting foreign matters other than doors. SOLUTION: An attraction plate 32 having protrusions 32a and 32b is mounted on a door and a door switch 31 is mounted on a doorframe. A case of the door switch 31 has slots 21b and 21c to receive the protrusions 32a and 32b, respectively. A built-in switch 24, a cam 25, and a compression spring 26 are housed within the case. When the attraction plate 32 is away from magnets MG of the door switch 31, the rotation of the cam 25 is locked, by the compression spring 26 and engaging means 22a and 25a, in a state in which the cam 25 is pressing down a push button 24a of the built-in switch 24. When the protrusions 32a and 32b enter the inside of the door switch 31 through the slots 21b and 21c, the cam 25 is first unlocked by the first protrusion 32a and is then rotated by the second protrusion 32b, thus the push button 24a of the built-in switch 24 is protruded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a door switch for detecting whether a door is open or closed. Such a door switch is a safety cover that opens and closes the opening of mechanical equipment,
Widely used for furniture doors.

[0002]

2. Description of the Related Art A conventional example of this type of door switch will be described with reference to FIGS. FIG. 1 shows a box (frame) 11 including a door (opening / closing door) 12 to which a door switch is attached.
FIG. 2 is a partially enlarged view of FIG. 2 (however, FIG. 2 is drawn upside down for easy viewing). FIG. 3 is a perspective view of the door switch.

As shown in FIGS. 1 and 2, a suction plate 13 made of a magnetic material is mounted inside a door 12,
A door switch 14 is mounted at a corresponding position of the first switch. As shown in FIG. 3, the door switch 14 is
A pair of magnets 15 (more precisely, a magnet and a yoke) for holding the door 12 in a closed state by adsorbing 3 is provided, and a push button (rod) 16 protrudes between them.

When the attraction plate 13 is attracted to the magnet 15 when the door 12 is closed, the push button 16 is pressed by the attraction plate 13, and as a result, the contact point of the microswitch mounted inside the door switch 14 opens. (Or close). Conversely, when the door 12 is opened, the push button 16 protrudes as shown in FIG. 3 and the contact of the microswitch closes (or opens) due to the action of the return spring mounted inside the door switch 14. Therefore, the open / closed state of the door 12 can be detected by electrically detecting the open / closed state of the contact of the microswitch. When the door 12 is made of a magnetic material such as steel, the suction plate 13 is unnecessary.

For example, when the above-mentioned door switch is provided on a safety cover for opening and closing an opening of mechanical equipment,
The signal of the door switch (micro switch) is used as a safety stop signal of the machine. That is, the safety is ensured by preventing the machine from being energized (not operating) when the door is open.

[0006]

However, in the conventional door switch 14 shown in FIGS. 1 to 3, since the push button 16 for opening and closing the contact of the built-in micro switch is protruding, the conventional door switch 14 is in a state in which the door 12 is open. There is a high possibility that an object other than the door 12 is pushed and erroneously detected that the door 12 is closed. In particular, when a magnetic material such as a metal gauge or tweezers is attracted to the magnet 15 of the door switch 14, the erroneous detection state continues, so that the machine is powered even though the door 12 is open. Dangerous conditions such as activation can occur.

In order to avoid the danger due to such erroneous detection, a structure as shown in FIG. 4 can be considered. In this configuration, the door switch 14 'does not have a protruding push button, but has a small hole 17 for accessing the built-in microswitch. Then, a protrusion 13a is provided on the suction plate 13 side.
Is provided. When the door 12 is closed, the suction plate 13
Is attracted to the magnet 15, the protrusions 1
3a enters the small diameter hole 17 of the door switch 14 'and opens and closes the contacts of the internal microswitch.

However, the door switch 1 shown in FIG.
4 'has a smaller possibility of being operated erroneously than the door switch 14 shown in FIGS. 1 to 3, but inserts a rod-shaped foreign substance such as the tip of a driver into the small diameter hole 17 of the door switch 14'. If this is the case, false detection can still be performed. Therefore, it cannot be said that sufficient safety can be ensured.

The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a safe door switch which is less likely to be erroneously detected by a foreign substance other than the door.

[0010]

According to a first configuration of the door switch according to the present invention, a projection is mounted on one of the door and the frame, and the projection is inserted into the other of the door and the frame. A case in which an opening is formed, a built-in switch housed in the case, and a rotary cam housed in the case, rotated by contact of the protrusion, and driving a push button of the built-in switch by the rotation. And characterized in that:

In a second configuration of the door switch according to the present invention, the first and second projections are mounted on one of the door and the frame, and the first and second projections are mounted on the other of the door and the frame. A case having first and second openings through which the projections are inserted; a built-in switch housed in the case;
A rotating cam that is housed in the case, rotates by abutment of the second protrusion, and drives a push button of the built-in switch by the rotation; and a lock unit that regulates rotation of the cam. The restriction of rotation of the cam by the locking means is released by the first protrusion.

Preferably, a magnetic body is mounted on one of the door and the frame, and a magnet for attracting the magnetic body is mounted on the other of the door and the frame. Further, it is preferable that the magnetic body and the protrusion are formed integrally.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A door switch according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 is an exploded view of the door switch according to the embodiment of the present invention. The door switch according to the present embodiment includes a built-in micro switch 24, a cam 25, a compression spring 26, and the like inside an exterior formed by a case 21, a lid 22, and a terminal cover 23. The case 21, the lid 22, and the terminal cover 23 are preferably made by injection molding of a synthetic resin such as PBT or nylon.

The terminal cover 23 has a rubber bush 23a through which a lead wire of a contact signal of the built-in micro switch 24 is inserted, similarly to the conventional door switch shown in FIG. The built-in micro switch (hereinafter simply referred to as built-in switch) 24 can be the same as that used for a conventional door switch, and has a push button (rod) 24a for opening and closing a contact. However, in the door switch of the present invention, the push button (rod) 24a is not exposed to the outside of the door switch, and is pressed indirectly via the cam 25.

A pair of magnets MG is mounted on the flat surface 21a of the case 21 opposite to the terminal cover 23. This magnet MG has a magnet body sandwiched between two yokes, and is the same as the magnet 15 of the conventional door switch shown in FIG. A pair of openings that expose the magnet 15 are provided apart from each other in the longitudinal direction of the flat surface 21a, and first and second slot holes 21b and 21c are formed therebetween. 2 slot holes 2
1b and 21c are flat surfaces 21a so that projecting portions 32a and 32b provided on a suction plate 32 described later can be inserted.
Are arranged obliquely so as to be separated from each other in the longitudinal direction and the width direction.

The built-in switch 24, the cam 25, and the magnet MG are fixed to the case 21 by inserting respective mounting holes into respective bosses 27, 28, 29 formed on the inner surface of the case 21. . However, a compression spring 26 is interposed between the cam 25 and the inner surface of the case 21, and the case 25, the lid 22 and the terminal The cover 23 is assembled.

FIGS. 6A and 6B are cross-sectional views showing a state where the suction plate 32 provided on the door side approaches the door switch 31 having the above-described structure. FIG. 6B is a diagram viewed from the left side of FIG. 6A. However,
The terminal cover 23 is omitted for easy viewing. The same applies to FIGS. 7A and 7B.

The suction plate 32 has first and second protrusions 32.
a and 32b. The first protrusion 32a is provided in the first slot hole 2 provided on the flat surface 21a of the door switch 31.
1b, the second protrusion 32b is provided in the second slot hole 2 provided in the flat surface 21a of the door switch 31.
1c.

FIGS. 7A and 7B show a state in which the suction plate 32 is further approached to the door switch 31 from the state of FIGS. 6A and 6B and is attracted to the pair of magnets MG. That is, a state in which the door is completely closed is shown. The operation when shifting from the state of FIGS. 6A and 6B to the state of FIGS. 7A and 7B is as follows.

First, in the state shown in FIGS. 6A and 6B, the push button 24a of the built-in switch 24 is in a state pressed by the cam 25. At this time, the built-in switch 24
The push button 24a attempts to return to the protruding state due to the restoring force of the spring built in the cam 22. However, the projection 22a provided on the inner surface of the lid 22 has engaged with the small hole 25a provided on the side surface of the cam 25 (see FIG. 5). Since the locked state is formed,
The pressed state of the push button 24a is maintained (locked).

This locked state is not easily released since the cam 25 is pressed against the lid 22 by the action of the compression spring 26 as described above. Even if a driver, tweezers, or the like is inserted from the second slot hole 21c, the cam 25 cannot be rotated by itself. At this time, the contacts of the built-in switch 24 are in an open state.
The machine is in a safe stop.

When the door is closed and the state shown in FIGS. 6A and 6B is changed to the state shown in FIGS. 7A and 7B, the first and The second protrusions 32a and 32b are inserted into the first and second slot holes 21b and 21c provided on the flat surface 21a of the door switch 31. The distal end face of the first projection 32a is formed in a tapered shape as shown in FIG. Also, the cam 25
A tapered portion 25b is also formed on the upper portion of the side surface on the side of the cover 22.

The first projection 32a is formed in the first slot hole 21b.
When the tapered tip surface of the cam 25 comes into contact with the tapered portion 25b of the cam 25, the first projection 32a enters between the cam 25 and the inner surface of the lid 22, and as a result, the cam 25
Is moved in a direction away from the inner surface of the lid 22 against the biasing force of the compression spring 26, whereby the projection 22a provided on the inner surface of the lid 22 engages with the small hole 25a provided on the side surface of the cam 25. The state (locked state) is released. Thereafter, the distal end portion 32c of the second protrusion 32b of the suction plate 32 pushes down the concave portion 25c of the cam 25, whereby the cam 2
5 rotates clockwise.

As a result, the state in which the push button 24a of the built-in switch 24 is pressed down by the cam 25 is released, and the push button 2
4a returns to the protruding state as shown in FIG. At this time, the contact of the built-in switch 24 is in a closed state, for example, the machine can be energized and the machine can be started. Further, the tip 32 of the second protrusion 32b of the suction plate 32
7c is in a state of being stuck in the concave portion 25c of the cam 25 as shown in FIG.

When the door is opened from the state shown in FIG. 7, the cam 25 is rotated counterclockwise so that the tip 32c of the second projection 32b of the suction plate 32 hooks the recess 25c of the cam 25. As a result, contrary to the above operation, the cam 25 pushes down the push button 24a of the built-in switch 24.
Then, as the first projection 32a of the suction plate 32 comes off from between the cam 25 and the inner surface of the lid 22, the compression spring 26
The cam 25 is pressed against the lid 22 by the action of
The engagement state (locked state) between the projection 22a provided on the inner surface of the cam 2 and the small hole 25a provided on the side surface of the cam 25 is formed again. In this way, the state returns to the state shown in FIG. 6, and the contacts of the built-in switch 24 are opened, so that the power supply to the machine is cut off, for example. It is preferable that the built-in switch 24 includes a forced opening mechanism for mechanically separating the contacts when the contacts are welded.

FIGS. 8A and 8B are a plan view and a side view showing a method of manufacturing the suction plate 32. FIG. In this example, the first and second sheets are attached to the suction plate 32 by bending the sheet metal.
Of the projections 32a and 32b.

FIG. 9 is a perspective view showing a method of manufacturing the suction plate 32 according to another embodiment. In this example, the first and second protrusions 32a and 32b are manufactured as separate members, and the first and second protrusions 32a and 32b are formed by caulking or the like.
Is fixed to the main body to produce the suction plate 32.

In the above embodiment, a normally open (NO) type built-in switch (micro switch)
However, the present invention is not limited to this, and a normally closed (NC) type built-in switch may be used.
A built-in switch having both O contacts and NC contacts may be used.

The door switch of the present invention can be applied not only to a door mechanism using a magnet and an attraction plate but also to a door mechanism in which a closed state of a door is maintained by a spring action. In addition, the door switch of the present invention can be implemented in various forms.

[0031]

As described above, according to the door switch, the push button for driving the contact of the built-in switch is not easily accessed from the outside, and the push button is indirectly driven via the rotating cam. Therefore, the possibility that the state of the contact of the built-in switch is switched by foreign matter other than the door is extremely low. Further, according to the configuration in which one of the two protrusions releases the locked state of the rotation cam and then rotates the rotation cam with the other protrusion to drive the push button, the contact state of the built-in switch is changed by foreign matter other than the door. The chance of switching is even lower.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a box including a door to which a door switch is attached.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a perspective view of a conventional door switch.

FIG. 4 is a perspective view showing a modification of the conventional door switch.

FIG. 5 is an exploded view of the door switch according to the embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a state when the door switch and the suction plate approach each other.

FIG. 7 is a cross-sectional view showing a state in which a suction plate is attracted to a magnet of the door switch.

FIG. 8 is a diagram showing an example of a method of manufacturing an attraction plate.

FIG. 9 is a view showing another example of a method of manufacturing the suction plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Box (frame) 12 Door (opening / closing door) 21 Case 21b Opening (1st slot hole) 21c Opening (2nd slot hole) 24 Built-in switch 24a Push button 25 Rotating cam 22a, 25a, 26 Locking means 32 Magnetic Body (adsorption plate) 32a First protrusion 32b Second protrusion MG magnet

Claims (4)

[Claims] 1. A case in which a projection is mounted on one of an opening / closing door and a frame, and a case in which an opening through which the projection is inserted is formed in the other of the opening / closing door and the frame, and is housed in the case. A door switch, comprising: a built-in switch; and a rotary cam that is housed in the case, is rotated by the contact of the protrusion, and drives a push button of the built-in switch by the rotation. 2. The first and second projections are mounted on one of the door and the frame, and the first and second projections are inserted through the other of the door and the frame. A case having an opening formed therein; a built-in switch housed in the case; a case housed in the case, rotated by abutment of the second protrusion, and the rotation of the push button of the built-in switch. A door switch comprising: a rotating cam that drives the cam; and a lock unit that restricts the rotation of the cam, wherein the first protrusion removes the restriction of rotation of the cam by the lock unit. 3. A magnetic body is mounted on one of the door and the frame, and a magnet for attracting the magnetic body is mounted on the other of the door and the frame.
The described door switch. 4. The door switch according to claim 3, wherein said magnetic body and said projection are formed integrally.