Electricity: circuit makers and breakers – Switch activation inhibitor – Removable actuator
Reexamination Certificate
2001-03-09
2002-11-19
Friedhofer, Michael (Department: 2832)
Electricity: circuit makers and breakers
Switch activation inhibitor
Removable actuator
C200S043040, C200S061620, C200S318000
Reexamination Certificate
active
06483053
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATION
This application claims all benefits accruing 35 U.S.C 119 from the Japanese Patent Application No. 2000-72875, filed on Mar. 15, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lock switch apparatus used as a safety door switch and the like.
2. Description of the Related Art
A safety door switch is mounted on a safety door for a machine and a door for a protective fence to prevent an accident caused by an inadvertent operation or accidental erroneous operation on various types of machine tools and industrial machines.
The safety door switch serves as an interlocking switch of a machine tool. For example, an operation key is installed on the door side and a switch body is installed on the fixed frame side of a doorway. When the door is closed, the operation key is inserted in the switch body so that an internal switch is turned on, whereby a drive start state is established. Inversely, by performing an operation for opening the door, that is, by removing the operation key from the switch body to turn off the internal switch, the machine tool is placed in the stopped state.
Generally, the lock switches are of two types: a mechanical lock type and a solenoid lock type. A key switch body of a lock switch S of a mechanical lock type has, as shown in FIG.
18
(
1
), a head unit
80
′, a detection switch unit
81
, a lock unit
82
for locking the detection switch unit
81
in an on state, a solenoid
83
for releasing a lock set by the lock unit
82
, and a switch unit
83
-
1
for detecting the release of lock effected by the solenoid
83
.
As shown in FIG.
18
(
2
), by inserting an operation key
76
′, a lock of a cam
84
is released, and the cam
84
is turned. Thereby, a second plunger
86
, which is connected to a first plunger
85
being in slidable contact with the cam
84
, is moved toward a head
80
′ by the urging force of a return spring
70
′. As a result, a contact face
86
A at the end of the second plunger
86
retracts from a plunger guide portion
88
into a guide wall portion
71
.
Thus, the second plunger
86
is placed in a state of moving to the maximum. In the detection switch unit
81
, therefore, a movable contact
87
a
of a first movable element
87
comes into contact with a fixed contact
89
a
of a first fixed terminal
89
, whereby a first switch
90
is placed in an on state. Also, a movable contact
91
a
of a second movable element
91
is separated from a fixed contact
92
a
of a second fixed terminal
92
, whereby a second switch
93
is placed in an off state. Thereby, it is verified that the detection switch unit
81
is operated.
In this case, a third plunger
96
of the lock unit
82
is advanced by the urging force of a locking spring
97
, so that the third plunger
96
comes into contact with the contact face
86
A at the end of the second plunger
86
, by which the detection switch unit
81
is locked in an on state.
As shown in FIG.
18
(
3
), the solenoid
83
is energized to retract a fourth plunger
94
connected to an iron core member
83
a
and thereby to turn a lever
95
around the turning center P, by which the third plunger
96
is moved against the locking spring
97
. Thereby, the third plunger
96
is removed from the contact face
86
A at the end of the second plunger
86
to release the lock of the detection switch unit
81
.
In this case, by the movement of the fourth plunger
94
, in the switch unit
83
-
1
, a movable contact
98
a
at both ends of a movable element
98
is separated from a fixed contact
99
a
of a fixed terminal
99
, so that a switch-off state is established. Therefore, since the switch unit
83
-
1
is placed in a switch-off state, the release of lock effected by the solenoid
83
is detected.
Also, by removing the operation key
76
′, the cam
84
is pulled by means of a transverse member
77
a
of the operation key
76
′ to turn the cam
84
reversely. By the reverse turning of the cam
84
, the second plunger
86
, which is connected to the first plunger
85
being in slidable contact with the cam
84
, is moved to the direction opposite to the head
80
′ against the return spring
87
, so that the contact face
86
A at the end of the second plunger
86
projects into the plunger guide portion
88
.
In the detection switch unit
81
, the movable contact
87
a
of the first movable element
87
is separated from the fixed contact
89
a
of the first fixed terminal
89
, so that the first switch
90
is placed in an off state. Also, the movable contact
91
a
of the second movable element
91
comes into contact with the fixed contact
92
a
of the second fixed terminal
92
, so that the second switch
93
is placed in an on state.
As shown in FIGS.
19
(
1
),
19
(
2
) and
19
(
3
), a lock switch S-
1
of a solenoid lock type is different from the lock switch S of a mechanical lock type in that an unlocking spring
97
-
1
is disposed in place of the locking spring
97
to release the lock of the third plunger
96
in the lock unit
82
. In this lock switch of a solenoid lock type, when the solenoid
83
is in an off state, a lock is not set, and only when the solenoid
83
is in an on state, a lock is set as shown in FIG.
19
(
3
). Other configurations are the same as those of the lock switch S of a mechanical lock type.
However, the above-described conventional lock switch apparatus has a construction such that the third plunger
96
is connected to the fourth plunger
94
, which is connected to the iron core member
83
a
of the solenoid
83
, via the lever
95
. Therefore, in order for the solenoid
83
to develop an attraction, a large-sized solenoid
83
is needed, which leads to an increased size and cost. Also, in the case where a vibration or impact is applied to the switch body, if the iron core weight increases in the large-sized solenoid
83
, the iron core is moved under the influence of an inertia force, easily causing a malfunction of switch signal, which presents a problem in that a malfunction of the apparatus occurs.
Also, in the case of the lock switch S-
1
of a solenoid lock type, since a lock must be set during the time when the apparatus is operated, the solenoid
83
must always be energized during this time, so that electric power is continuously consumed, which presents a problem in that the equipment cost increases.
The present invention has been made paying attention to the above problems, and accordingly an object thereof is to provide a lock switch apparatus in which a small-sized solenoid can be used, so that the outside size of a switch can be decreased, whereby handling by the user can be made easy.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a lock switch apparatus comprising: a key insertion unit; a detection switch unit for detecting the insertion of an operation key in the key insertion unit; a lock unit for locking the operation key when the operation key is inserted in the key insertion unit; and a lock detection unit for detecting the operation state of the lock unit, wherein the detection switch unit has a plunger which is moved by the insertion of the operation key in the key insertion unit to operate a switch element, the lock unit has a slide lock member for locking the plunger by the movement thereof and a solenoid for operating a solenoid-side movable portion by being energized, the solenoid-side movable portion of the solenoid is connected to the slide lock member by a lever having a turning center in an intermediate portion thereof, and the slide lock member is moved at the ratio of the lever with respect to the operation of the solenoid-side movable portion, whereby the plunger is locked.
By the above-described configuration, the plunger can be locked by moving the slide lock member at the ratio of the lever with respect to the operation of the solenoid-side movable portion. Therefore, the slide lock member can be moved by using the solenoid-side movable portion in a zone in which the attraction of th
Hibi Masaharu
Kajio Hiroyuki
Kobayashi Mitumi
Koshiba Yoshihito
Takenaka Hidemitu
Foley & Lardner
Friedhofer Michael
Omron Corporation
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