Electricity: circuit makers and breakers – Electric switch details – Actuators
Reexamination Certificate
2000-12-27
2002-09-24
Enad, Elvin (Department: 2832)
Electricity: circuit makers and breakers
Electric switch details
Actuators
C200S0050EA, C200S517000, C400S490000, C400S492000
Reexamination Certificate
active
06455794
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a key switch device in which vertical and horizontal motions of a key top are guided and supported with a pair of link members which are operated synchronously when the key top is depressed with favorable operability; a keyboard provided with the key switch device; and an electronic apparatus provided with the keyboard; and particularly to a key switch device provided with link members including gear parts with improved structures for allowing synchronous action of the link members; a keyboard provided with the key switch device; and an electronic apparatus provided with the keyboard.
The present invention also relates to a key switch device in which a horizontal motion of a key top in course of depression is restrained to provide stable key operability, a keyboard provided with the key switch device, and an electronic apparatus provided with the keyboard.
Moreover, the present invention relates to a key switch device in which a guide member including a key top is removably mounted on a circuit board, a keyboard provided with the key switch device, and an electronic apparatus provided with the keyboard.
2. Description of Related Art
Conventionally, various types of key switch devices have been proposed. In association with the recent trend toward a thin key switch device, enhancement of key operability, etc., there has been proposed a key switch device in which a pair of link members support a key top for guiding vertical movement of the key top, and the link members are operated in synchronization with each other upon depression of the key top, thus achieving a reduction in thickness (height) of a key switch device and an enhanced key top operability.
For example, Japanese patent unexamined publication No. 11-003628 discloses a key switch device in which a pair of bearing portions each having two bearing holes are provided on the underside of a key top and a guide claw is provided at each end of two recesses formed on the upper surface of a support part. In this device, two support shafts of one gear link member are rotatably supported in the bearing holes, and also each end of a support shaft is slidably supported between the recess and the guide claw. Two support shafts of the other gear link member are rotatably supported in the bearing holes, and also each end of a support shaft is slidably supported between the recess and the guide claw.
In the above key switch device, a pair of middle shafts constituting each of the two gear link members is formed with gear portions having one tooth or two teeth at the upper ends. The tooth or teeth of each gear portion of the middle shaft of the gear link member engage the tooth or teeth of each gear portion of the middle shaft of the other gear link member. When the key top is depressed from a non-depression position (original position) through elasticity of a protrusion of an actuator provided on a rubber sheet, the support shafts of the gear link members are rotated in the bearing holes, while each of the support shafts is slid outwardly between the recess and the guide claw. At this time, the teeth of the gear portions of the gear link members are engaged with each other, thereby allowing synchronous operation of the link members.
The structure of the gear portion of each gear link member adopted in the key switch device in the abovementioned publication is explained below with reference to FIG.
26
.
FIG. 26
is a schematic perspective enlarged view of the gear portions of the gear link members in the conventional key switch device. In
FIG. 26
, a first gear link member
100
has a pair of middle shafts
101
and
102
on which support shafts
103
and
104
are provided protruding outwardly. The support shafts
103
and
104
are rotatably supported in the bearing holes of bearing portions provided on the underside of the key top.
Like the first gear link member
100
, a second gear link member
105
has a pair of middle shafts
106
and
107
on which support shafts
108
and
109
are provided protruding outwards. The support shafts
108
and
109
are rotatably supported in the bearing holes of the other bearing portions provided on the underside of the key top.
A gear portion
110
is formed in the tip end of a middle shaft
101
of the first gear link member
100
. This gear portion
110
is provided with a single gear tooth
111
. A gear portion
112
is formed in the tip end of a middle shaft
102
. This gear portion
112
is provided with double gear teeth
113
.
A gear portion
114
is formed in the tip end of a middle shaft
106
of the second gear link member
105
. This gear portion
114
is provided with double gear teeth
115
. The gear tooth
111
of the gear portion
110
of the middle shaft
101
of the first gear link member
100
is engaged between the double gear teeth
115
of the gear portion
114
of the middle shaft
106
. A gear portion
116
is formed in the tip end of a middle shaft
107
of the second gear link member
105
. This gear portion
116
is provided with a single gear tooth
117
. This gear tooth
117
is engaged between the double gear teeth
113
of the gear portion
112
of the middle shaft
102
of the first gear link member
100
.
As above, the gear tooth
111
of the middle shaft
110
is engaged with the gear teeth
115
of the middle shaft
106
, while the gear teeth
113
of the middle shaft
102
are engaged with the gear tooth
117
of the middle shaft
107
. Thus, as the key top is depressed, the first and second gear link members
100
and
105
are synchronously operated, allowing downward movement of the key top with its horizontal condition maintained.
Meanwhile, an electronic apparatus such as notebook-size computers, mobile computer devices and the like have come into wide use rapidly. In association with this, a reduction in thickness of a keyboard associated with such the electronic apparatus has been promoted year after year. Accordingly, a key switch device is increasingly required to be reduced in thickness.
In the conventional key switch device mentioned above, however, the gear teeth
113
of the middle shaft
102
of the first gear link member
100
and the gear teeth
115
of the middle shaft
106
of the second gear link member
105
are formed in a double teeth configuration of an upper and lower teeth aligned and spaced in the thickness direction of the middle shaft
102
or
106
. To help a further reduction in thickness or height of a key switch device, the gear teeth
113
and
115
have to be further reduced in thickness and size.
This makes it difficult to assemble the gear tooth
111
of the first gear link member
100
and the gear teeth
115
of the second gear link member
105
, and the gear teeth
113
of the first gear link member
100
and the gear tooth
117
of the second gear link member
105
in a proper engagement relationship. As a result, an assembling efficiency of the key switch device would be deteriorated.
As mentioned above, the gear teeth
113
and
115
must be reduced in thickness and size to achieve a thinner key switch device, resulting in a decrease in durability of the gear teeth
113
and
115
. Thus, a key switch device with high durability for long-term use could not be achieved.
In the case where the gear teeth
113
and
115
are made of a resin, each of which has a double teeth configuration; upper and lower teeth provided in aligned and spaced relation in the thickness direction of the middle shaft
102
or
106
, the gear link member
100
(
105
) having such the gear teeth
113
(
115
) could not be molded by only a simple die constructed of upper and lower parts which are opened in the shaft thickness direction. In this case, a slide die which is removably arranged in parallel to the teeth is further needed to form the double teeth configuration. This slide die necessarily occupies space. Accordingly, the number of gear link members to be made with use of one die would be reduced. This decreases production efficiency of the gear link
Mochizuki Isao
Sato Hirofumi
Brother Kogyo Kabushiki Kaisha
Enad Elvin
Lee Kyung S.
Oliff & Berridg,e PLC
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