Electricity: circuit makers and breakers – Electric switch details – Actuators
Reexamination Certificate
2004-02-19
2004-12-21
Lee, Kyung (Department: 2832)
Electricity: circuit makers and breakers
Electric switch details
Actuators
C200S0050EA, C200S01700A, C400S490000
Reexamination Certificate
active
06833522
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a key switch device, and more particularly to a key switch device having a structure capable of preventing its key top from being tilted, thereby maintaining the key top in a stable use state, while easily providing a desired waterproofing effect.
2. Description of the Related Art
Generally, portable electronic devices such as notobook computers use a keyboard including a plurality of key switch devices for a key input operation. Each key switch device includes a guide member consisting of a pair of links connected to each other in a crossing manner while being movable with respect to each other. The guide member has a function for guiding vertical movement of the key top to thereby effect a switching operation.
Such a key switch device is disclosed in a number of publications. An example of such a key switch device is disclosed in the Japanese Patent Publication No. 2924427 titled “KEY SWITCH DEVICE”. Now, the structure of the key switch device disclosed in the publication will be described in brief with reference to FIG.
1
.
The key switch device shown in
FIG. 1
includes a key top
101
provided at a lower surface thereof with two mounting portions
102
and
103
vertically downwardly protruded from the lower surface of the key top
101
, and a switching member
131
provided at its inner surface with a downward protrusion, and adapted to perform a switching operation in accordance with vertical movement of the key top
101
. A support member
106
is arranged between the key top
101
and the switching member
131
. The support member
106
includes two link members
107
and
108
connected to each other such that they are movable with respect to each other. Each of the link members
107
and
108
is provided at opposite ends thereof with mounting pins
115
and
121
, respectively.
A flexible printed circuit board
130
is arranged beneath the switching member
131
while being supported by the upper surface of a support plate
125
. Mounting pieces
135
and
136
corresponding to respective mounting portions
102
and
103
of the key top
101
are provided at the support plate
125
.
The support plate
125
is made of a metal plate. The mounting pieces
135
and
136
are formed by cutting desired portions of the support plate
125
, and then upwardly bending the cut portions. Accordingly, the mounting pieces
135
and
136
are integral with the support plate
125
. The flexible printed circuit board
130
is provided with through holes (not shown) corresponding to respective mounting pieces
135
and
136
.
The switching member
131
is made of a rubber material, so that it can serve to upwardly urges the key top
101
against a downward force applied to the key top
101
by its resilience.
In the conventional key switching device having the above mentioned configuration, the link members
107
and
108
move mutually in a scissors fashion when the user depresses the key top
101
, thereby causing the key top
101
to move downwardly. When the depressing force is released, the key top returns to its original position by virtue of the resilience of the switching member
131
. In the above procedure, the switching member
131
comes into contact with a contact on the flexible printed circuit board
130
, thereby effecting a switching operation.
However, the above mentioned conventional key switch device has the following drawbacks.
First, there is a drawback in that it is difficult to machine the mounting pieces
135
and
136
, to be engaged with the mounting pins
115
and
121
, in a high accuracy because they should be integrally formed with the support plate
125
, made of a metal, while having a structure protruded from the support plate
125
. Accordingly, the support plate
125
is typically manufactured, using a relatively flexible metal material such as aluminum, in order to easily machine the mounting pieces
135
and
136
in a high accuracy. In this case, however, the mounting pieces
135
and
136
may be easily bent or broken, even when they are subjected to low pressure, because the strength of aluminum is low. Even when any one of the mounting pieces
135
and
136
is bent or broken, the support plate
125
cannot operate normally, so that it is necessary to replace the support plate
125
with a new one.
Where the support plate
125
is used for a keyboard including a plurality of key switch devices, it has a structure in which a plurality of mounting pieces
135
and
136
associated with the key switch devices are arranged in the form of a matrix. In this case, the formation of the mounting pieces
135
and
136
becomes more difficult in proportion to the number of the mounting pieces
135
and
136
. As a result, it is difficult to manufacture the support plate
125
.
Meanwhile, each key switch device included in a keyboard equipped in a notebook computer is required to have a structure in which its key top
101
is horizontally maintained at a constant level without being tilted, while having a long stroke.
In the above mentioned conventional key switch device, however, it is difficult to machine the mounting pieces
135
and
136
in the high accuracy required in the key switch device. Since the mounting pieces
135
and
136
are made of a flexible material such as aluminum, they may also be easily bent, tilt to one side thereof, or broken, even when they are subjected to low pressure. For this reason, the key top
101
may be tilted without being horizontally maintained.
Since the mounting pins
115
and
121
have a cylindrical shape, their area contacting the mounting pieces
135
and
136
and the support plate
125
is also small. As a result, the mounting pins
115
and
121
cannot stably support the key top
101
. Furthermore, there is no structure for maintaining the key top
101
in a horizontal state. For this reason, it is impossible to prevent the key top
101
from being tilted.
In the above mentioned key switch device, its mounting pieces
135
and
136
are formed by cutting desired portions of the support plate
125
, and bending the cut portions such that the cut portions are protruded from the support plate
125
. As a result, holes are perforated through the support plate
125
at regions where the mounting pieces
135
and
136
are formed, respectively. For this reason-, there is a drawback in that it is necessary to attach a waterproofing tape to the lower surface of the support plate
125
or to otherwise close the holes, in order to waterproof the keyboard.
This results in an increase in the number of elements to be assembled and an increase in the number of assembly processes, thereby causing a degradation in productivity and an increase in manufacturing cost.
Also, in the conventional key switch device, the link members
107
and
108
are directly coupled to the mounting pieces
135
and
136
formed at the support plate
125
, respectively. For this reason, the sliding movements of the link members
107
and
108
are limited by the height of the mounting pieces
135
and
136
formed by the cut portions of the support plate
125
. Thus, the mounting pieces
135
and
136
serve as stoppers determining the height of the key switch device. In other words, the thickness of the support plate
125
determining the height of the keyboard corresponds to the thickness of the mounting plates
135
and
136
. Accordingly, it is necessary to increase the thickness of the mounting plates
135
and
136
for a stable use state of the keyboard. In this case, however, there is a problem in that the height of the keyboard increases.
SUMMARY OF THE INVENTION
Therefore, the present invention has been made in view of the above mentioned problems, and an object of the invention is to provide a key switch device in which mounting pieces, to be engaged with mounting pins for guiding vertical movement of a key top, are formed, separately from a support plate adapted to support a printed circuit board, so that the support plate can be easily manu
Lee Jeong-Hun
Min Chul-Gi
Park Kyung-Su
Gottlieb Rackman & Reisman P.C.
Lee Kyung
Samsung Electro-Mechanics Co. Ltd.
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