Key switch

Details Key switch Key switch

1999-07-29

2001-10-23

Bradley, Paula (Department: 2832)

Electricity: circuit makers and breakers

Switch activation inhibitor

Actuator locking device

C200S043040

Reexamination Certificate

active

06307167

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a key switch, and particularly to an improved key switch utilized, for example, as a safety switch of a door.
2. Description of the Related Art
A conventional safety switch of a door is mounted in a safety door or a care fence on equipment in order to prevent accidents by unprepared operations or accidental operations beforehand in various machine tools and industry equipment.
This kind of safety switch is designed to be inoperable with a tool, for example, a screw driver, except for an exclusive key, and lock its internal apparatus in an initial condition that the key is pulled out, an example of which is shown in
FIGS. 32 and 33
.
In this conventional safety switch, cam plate
104
is rotated by the insertion-and-pull-out movement of a key
103
as to a key insertion opening
102
, and a plunger
105
coming into contact with a peripheral cam surface of the cam plate
104
is displaced in accordance with the rotational movement of the cam plate
104
so as to switch a switch mechanism (not shown in drawings), and there is provided a rotational lock mechanism for locking the rotation of the cam plate
104
in the initial position when the key
103
is pulled out.
This rotational lock mechanism
106
includes a pair of forward and backward locking members
107
disposed near the periphery of the cam for a forward-and-backward movement in a rotary axial direction “q” of the cam plate
104
, and a spring
108
for urging the locking members
107
toward the cam
104
, in which a lock pin
109
projecting from the locking member
107
is urged to be engaged with an engagement concave portion
110
formed at the periphery of the cam plate
104
so as to fix the cam plate
104
at the initial position.
Each locking member
107
includes a cam slant
111
directed to the key insertion opening
102
for lock release. As shown in
FIG. 33
, a point of the key
103
inserted in the key insertion opening
102
pushes the lock release cam slant
111
of each locking member
107
so as to move each locking member
107
backward against the spring
108
to release the locking for rotating the cam plate
104
by the subsequent insertion operation of the key
103
According to the conventional rotation lock mechanism
106
of the above-mentioned construction, the locking member
107
is disposed for a forward-and-backward movement in a rotary axial direction “q” of the cam plate
104
, so that the arrangement space of the locking member
107
and the lock push spring
108
is large in the rotation axial direction “q” of the cam plate
104
, so that the thickness of the whole switch in the forward and backward direction is bulky.
A pair of locking members
107
have to be disposed in front and back of the cam plate
104
to comply with the standard, whereby the space in the forward-and-backward direction of rotation lock mechanism
106
is enlarged causing a bulky key switch.
SUMMARY OF THE INVENTION
It is, therefore, a primary object of this invention to provide a thinner switch body an improved rotation lock mechanism.
According to a first aspect of this invention, there is provided a key switch including a cam member rotating in accordance with the insertion-and-pull of a key to be inserted into a key insertion opening, a plunger coming into contact with the circumferential cam side of the cam member, a switch mechanism actuated by the plunger which is displaced in accordance with the rotation of the cam member, and a rotation lock mechanism for locking the rotation of the cam member when the key is pulled, the rotation lock mechanism including a locking member which can be displaced in the direction parallel with a vertical rotation face on the rotation axis of the cam member and a spring urging the locking member toward a position to be engaged with the cam member, and the locking member being disposed to be displaced to a lock release position by contacting the key resisting the spring.
The rotation face is not limited to a surface of the rotating cam member, but includes a virtual rotation face of the interior which run through the cam member if it is perpendicular to a rotation axis of the cam member.
As the key is inserted into the key insertion opening, the key comes into contact with the locking member, and the locking member is displaced backward into the lack release position against the spring in the direction in parallel with a vertical rotation face on the rotation axis of the cam member. As the key is further inserted, the cam member is rotated in a predetermined direction and the plunger is displaced to switch contacts of the switch mechanism. The locking member is displaced in the direction parallel with the rotation face of the cam member, and not displaced in the rotational axis of the cam plate, that is, the forward-and-backward direction of the switch, so that the space for the lock mechanism in the forward and backward direction may be limited to a small space for accommodating the locking member, whereby the width of the whole configuration of the switch can be reduced.
According to a second aspect of this invention, there is provided a key switch including a cam member rotating in accordance with the insertion-and-pull of a key to be inserted into a key insertion opening, a plunger coming into contact with a circumferential cam side of the cam member, a switch mechanism actuated by the plunger which is displaced in accordance with the rotation of the cam member, and a rotational lock mechanism for locking the rotation of the cam member when the key is pulled, the rotational lock mechanism including a locking member which can be displaced in the direction parallel with a vertical rotation face in the rotational axis of the cam member, an intermediate operating member which comes into contact with the locking member for moving the same, and a spring urging the locking member toward a position to be engaged with the cam member, and the locking member being disposed to be displaced to a lock release position resisting the spring by displacing the intermediate operating member by the insertion of the key.
As the key is inserted into the key insertion opening, the key first comes into contact with the intermediate operating member and the locking member to displace the same, the locking member is touched and actuated by the intermediate operating member to be displaced backward into the lock release position against the spring in the direction parallel with a vertical rotation face in the rotational axis of the cam member. As the key is further inserted, the cam member is rotated in a predetermined direction and the plunger is displaced to switch contacts of the switch mechanism. The locking member is displaced in the direction parallel with the rotation face of the cam member, and not displayed in the rotational axis of the cam plate, that is, the forward-and-back ward direction of the switch, so that the space for the lock mechanism in the forward and backward direction may be limited to the space for accommodating the locking member.
The locking member is adapted not to be displaced in the rotational axis of the cam plate, whereby the space for the lock mechanism in the forward and backward direction may be reduced to a small space for accommodating the locking member, whereby the width of the whole configuration of the switch can be reduced. The locking member is not directly actuated by the key, but is indirectly actuated through the intermediate operating member, whereby the setting position of the locking member may be freely selected as to the key insertion position, and the cam member may be locked in the best position.
According to a third aspect of this invention, there is provided a key switch in the second aspect of this invention, in which the intermediate operating member is supported together with the cam member, and the intermediate operating member rotates together with the cam member in accordance with the rotation of the cam member after the lock release and includes a circ

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