Switch device

Details Switch device Switch device

2001-08-03

2002-08-13

Friedhofer, Michael (Department: 2832)

Electricity: circuit makers and breakers

Snap

Double snap

C200S434000, C200S439000, C200S520000, C200S533000

Reexamination Certificate

active

06433291

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a switch device used as a power switch of an electronic device, and more particularly, to the structure of a quick-acting switch device in which contacts are opened and closed by using the inversion of a spring.
2. Description of the Related Art
The structure of a conventional quick-acting switch device is shown in
FIGS. 13
to
15
.
FIG. 13
is a longitudinal sectional view showing an OFF state of the switch device.
FIG. 14
is a longitudinal sectional view showing an ON state of the switch device.
FIG. 15
is a partial explanatory view of a contact mechanism section.
The illustrated conventional switch device principally includes a casing
21
made of an insulating material, such as a synthetic resin. A fixed terminal
22
is placed on the inner bottom surface of the casing
21
and has a fixed contact
22
a
on its upper surface. A center terminal
23
is similarly placed on the inner bottom surface of the casing
21
adjacent to the fixed terminal
22
. A conductor plate
28
is movably supported by the center terminal
23
and has at one end a movable contact
29
that is movable closer to and further apart from the fixed terminal
22
. A support plate
27
is retained by the conductor plate
28
and the center terminal
23
so as to movably support the conductor plate
28
, a leaf spring
30
retained in a bent form between the conductor plate
28
and the center terminal
23
so as to move the conductor plate
28
by its bending and stretching motions, and a slide member
31
for moving a projection
30
a
of the leaf spring
30
in contact therewith so as to shift the conductor plate
28
closer to and further apart from the fixed terminal
22
.
The center terminal
23
is made of a conductive metal plate or the like, and includes a support plate retaining projection
23
a
for retaining the support plate
27
and a leaf spring retaining projection
23
b
for retaining the leaf spring
30
. The support plate retaining projection
23
a
and the leaf spring retaining projection
23
b
have, respectively, retaining V-grooves
23
c
and
23
d
formed nearly opposed to each other. The support plate
27
and the leaf spring
30
are retained at one end by the retaining groves
23
c
and
23
d
respectively.
The support plate
27
is similarly made of a conductive metal plate, is substantially U-shaped, and has an opening at the center where the leaf spring retaining projection
23
b
can be loosely fitted. The support plate
27
is retained by the retaining V-groove
23
c
of the support plate retaining projection
23
a
at one end, and is retained adjacent to the side of the conductor plate
28
, where the movable contact
29
is attached, at the other end.
The conductor plate
28
is similarly made of a conductive metal plate, and has at its center an opening where the support plate retaining projection
23
a
and the leaf spring retaining projection
23
b
can be loosely fitted, and the movable contact
29
at one end. The conductor plate
28
is movably mounted on the center terminal
23
while one end of the support plate
27
is retained at one inner end of the opening, and the other end of the opening is retained by the leaf spring
30
.
The leaf spring
30
is made of an elastic thin metal plate, and is substantially V-shaped. One end of the leaf spring
30
is retained by the retaining V-groove
23
d
of the leaf spring retaining projection
23
b
of the center terminal
23
, and the other end thereof is retained on the inner side of the opening of the conductor plate
28
opposite from the side where the support plate
27
is retained. The leaf spring
30
is placed in a bent form between the center terminal
23
and the conductor plate
28
. Adjacent to the top of the nearly V-shaped leaf spring
30
, an operating projection
30
a
is formed so as to drive the conductor plate
28
when the slide member
31
slides.
In order to assemble the contact mechanism of the above-described switch device, since the conductor plate
28
is movably mounted on the center terminal
23
, the leaf spring
30
must be placed in a bent form between one inner end of the opening of the conductor plate
28
and the leaf spring retaining projection
23
b
of the center terminal
23
in a state in which one end of the support plate
27
is retained at the other inner end of the opening of the conductor plate
28
, and the other end of the support plate
27
is retained by the support plate retaining projection
23
a
of the center terminal
23
. In this case, since the leaf spring
30
is mounted in an elastically bent form between the conductor plate
28
and the center terminal
23
with the support plate
27
therebetween, the conductor plate
28
, the support plate
27
, and the leaf spring
30
are movably mounted together on the center terminal
23
.
The operation of the above switch device will now be described. When the slide member
31
is pressed, it slides in the pressing direction (rightward in the figure) and presses the adjacency of the top of the V-shaped leaf spring
30
, and the leaf spring
30
is pivoted clockwise on the retaining V-groove
23
d
of the leaf spring retaining projection
23
b
of the center terminal
23
. In this case, the conductor plate
28
is turned downward together with the support plate
27
on the retaining V-groove
23
c
of the support plate retaining projection
23
a
of the center terminal
23
. When the retaining portion between the conductor plate
28
and the leaf spring
30
passes over the retaining V-groove
23
c
(the point of inversion of the leaf spring
30
), the conductor plate
28
moves downward and the movable contact
29
contacts the fixed contact
22
a
, thereby closing the circuit. In this case, the slide member
31
is locked in a pressed position.
When the slide member
31
is further pressed in this state, it is unlocked and returned by the urging force of the return spring
26
in a direction (leftward in the figure) opposite from the pressing direction. In this case, when the operating projection
30
a
of the leaf spring
30
is pressed, and the leaf spring
30
is pivoted counterclockwise and passes through the point of inversion, the conductor plate
28
moves upward, and the movable contact
29
separates from the fixed contact
22
a
, thereby opening the circuit.
In the above-described conventional switch device, the leaf spring
30
is used in order to move the conductor plate
28
and, at the inversion of leaf spring
30
, to establish a contact between the movable contact
29
and the fixed contact
22
a
. However, since the required load is heavy, the leaf spring
30
must be made of a spring material with a great allowable stress (for example, titanium copper or beryllium copper). This makes it difficult to maintain machinablility and dimensional accuracy, and increases the parts cost.
Furthermore, since the support plate
27
and the leaf spring
30
are made of a platelike material, the shape is complicated, and the material yield is low. Since the support plate
27
and the leaf spring
30
contact with the center terminal
23
at cut edge portions, they are prone to wear, and the reliability of the contact portion is decreased.
SUMMARY OF THE INVENTION
The present invention has been made in order to overcome the above problems, and an object of the invention is to provide a quick-acting switch device in which machinablility and dimensional accuracy can be easily maintained the cost can be reduced, and the reliability of the contact portion can be improved by making a spring member of a contact mechanism of a round wire.
In order to achieve the above object, according to an aspect of the present invention, there is provided a switch device including a fixed contact, a conductor plate having a movable contact which is moved closer to and further apart from the fixed contact, a center terminal for movably supporting the conductor plate, a support arm retained by the conductor plate at one end and retained by the cente

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