Electricity: circuit makers and breakers – Electric switch details – Actuators
Reexamination Certificate
2002-04-30
2003-03-25
Friedhofer, Michael (Department: 2832)
Electricity: circuit makers and breakers
Electric switch details
Actuators
C200S341000
Reexamination Certificate
active
06538222
ABSTRACT:
This application claims priority of Taiwan Patent Application Serial No. 090111131 filed on May 10, 2001.
FIELD OF INVENTION
The present invention relates to a push button switch apparatus and a method of assembling the same, and more particularly, to a push button switch apparatus used in a keyboard apparatus and a method of assembling the same.
BACKGROUND OF THE INVENTION
As the development of portable electronic technologies continues, engineers continually attempt to further reduce the size of such devices. In order to provide smaller keyboard devices, for example, there is a continued attempt to improve the design of push button switches used as keys in miniaturized keyboards.
FIG.
1
(A) is a schematic diagram of a conventional push button switch apparatus
10
. The push button switch apparatus
10
has a scissors-like structure including a key cap
11
, a base plate
12
, an elastically deformable actuator
13
, a first arm
14
, and a second arm
15
. The first arm
14
and the second arm
15
are typically pivotally connected together via a pivot axle
16
so as to form the scissors-like structure of the push button switch apparatus
10
. A thin film circuit board
121
is appropriately disposed on the base plate
12
. A pivotal ear
123
and a bearing portion
124
are typically formed on the base plate
12
.
The first arm
14
has a pivot axle
141
at its one end, and the pivot axle
141
is typically rotatably disposed in a groove
1231
of the pivotal ear
123
. The second arm
15
has a pivot axle
151
at its one end, and the pivot axle
151
is slidably rotatable within a space
1241
between the bearing portion
124
and the base plate
12
. The downward action of the key cap
11
causes the elastically deformable actuator
13
to downwardly press the thin film circuit board
121
to generate input signals. The scissors-like structure consists of first arm
14
and second arm
15
, and functions as a holder for the deformation of the elastically deformable actuator
13
and for the up-and-down movement of the key cap
11
. The thin film circuit board
121
is typically made of elastic materials, so it is regarded as a flexible layer.
Both FIG.
1
(B) and FIG.
1
(C) are top views of portions of elements of the push button switch apparatus
10
in FIG.
1
(A) showing a method of assembling the pivot axle
141
into the groove
1231
of the pivotal ear
123
. A typical scissors-like structure includes two first arms
14
connected by a shaft. Each first arm
14
typically has a U-shaped frame, as shown. Before being assembled, first arm
14
is typically pressed by a force along a direction shown as the arrowhead in FIG.
1
(B), and first arm
14
is deformed to enable the pivot axle
141
to align with the groove
1231
of the pivotal ear
123
. The first arm
14
is then released to make the pivot axle
141
move into the groove
1231
, shown in FIG.
1
(C).
Accordingly, with the design of the pivotal ear
123
, the typical assembling method relies upon the deformation of the first arm
14
, which results in complexity of assembly. It is therefore desirable to devise a switch structure that is assembled without the deformation of the first arm
14
. Additionally, it is also desirable that a switch structure prevents the push button switch from disconnecting as the pivot axle
141
moves within the groove
1231
.
SUMMARY OF THE INVENTION
In the first exemplary embodiment of the present invention, a push button switch apparatus includes a base plate and a first arm. The base plate includes a first bearing portion and a recess, wherein a pivot bearing space is formed between the base plate and the first bearing portion, and an entrance is formed on the base plate. The first arm includes a pivot axle at a first end, and the pivot axle has a protrusion. The protrusion is disposed into the recess, and the pivot axle enters into the pivot bearing space during assembly process by deforming the protrusion or the pivot axle. The walls defined by the recess constrain the pivot axle within the pivot bearing space, while the first arm selectively rotates along the pivot axle.
The second exemplary embodiment further includes a flexible layer having a second entrance on the base plate. The walls defined by the second entrance constrain the protrusion of the pivot axle and pivot axle within the pivot bearing space. One embodiment of the flexible layer is a thin film circuit board.
In the third exemplary embodiment of the present invention, the pivot axle is a short-spindle axle. By adjusting the position of the second entrance, walls defined by the second entrance constrain the protrusion of the pivot axle and pivot axle is allowed to move within the pivot bearing space.
In the fourth exemplary embodiment of the present invention, there is no protrusion on the pivot axle. The pivot axle is surrounded by the second entrance by adjusting the position of the second entrance. The pivot axle is forced into the second entrance through deformation of the shape of the second entrance. The walls defined by the second entrance constrain the pivot axle within the pivot bearing space.
In the fifth exemplary embodiment of the present invention, the pivot axle is a short-spindle axle and does not have a protrusion on the pivot axle. The walls defined by the second entrance constrain the pivot axle within the pivot bearing space.
These and other aspects of the present invention will no doubt become apparent to those of ordinary skill in the art after having read the following detailed description of the exemplary embodiments which are illustrated in the various figures and drawings.
REFERENCES:
patent: 5278372 (1994-01-01), Takagi et al.
patent: 5329084 (1994-07-01), Watanabe et al.
patent: 5767464 (1998-06-01), Dyer et al.
patent: 6448520 (2002-09-01), Inoue
Darfon Electronics Corp.
Friedhofer Michael
Klaus Lisa N.
Snell & Wilmer L.L.P.
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