Electricity: circuit makers and breakers – Multiple circuit control – Multiple switch
Reexamination Certificate
2000-10-13
2001-10-02
Bradley, Paula (Department: 2832)
Electricity: circuit makers and breakers
Multiple circuit control
Multiple switch
C200S344000
Reexamination Certificate
active
06297461
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a keyboard switch for a lidded computer case. More particularly, the present invention relates to a keyboard switch that retracts multiple key switches from a stand-by orientation to a narrower storage orientation.
2. Description of the Prior Art
Conventionally known is a keyboard switch that retracts a plurality of key switches to a storage orientation within a lidded computer case.
A shown in
FIGS. 7 through 9
, a conventionally known keyboard switch (not shown) contains a plurality of key switches
100
each containing a cross-link
101
. Each cross-link
101
includes a first link member
101
a
and a second link member
101
b
pivotably coupled at intermediate pivot points
101
c
. Each cross-link
101
is located between a key top
102
and a support plate
107
.
A bottom end of first link member
1
O
1
a
hinges to a hinged end portion
110
and couples pivotally to a support projection
109
formed from support plate
107
. A top end of first link member
101
a
, having a pivotal and slidable end portion
111
, engages a guide portion
105
formed on the underside of key top
102
. Thus, first link member
101
a
both pivots and slides in a left-to-right direction in
FIGS. 7 through 9
.
A bottom end of second link member
101
b
, having a pivotable and slidable end portion
112
, engages an engagement long hole
108
. A top end of second link member
101
b
hinges to a hinged end portion
113
and couples pivotally to the underside of key top
102
.
In
FIG. 7
, keyboard switch
100
is shown in a stand-by position. A dome shaped rubber elastic portion
114
is disposed under key top
102
, and serves as a return spring. Elastic portion
114
is in contact with the underside of a depressing portion
106
projected perpendicularly from the bottom side of key top
102
.
Elastic portion
114
is formed integrally with a rubber sheet
104
on switch sheet
103
. A membrane switch portion
103
a
is formed integrally with switch sheet
103
. Switch sheet
103
is disposed continuously under keyboard switch
102
. Rubber sheet
104
and switch sheet
103
are slidable together on support plate
107
.
Depressing key top
102
(from above in
FIG. 7
) causes key top
102
, guided by cross-link
101
, to lower in parallel with switch sheet
103
, toward switch sheet
103
, without significantly inclination. Depressing key top
102
, depresses depressing portion
106
and deforms elastic portion
114
. Deformed elastic portion
114
contacts and actuates membrane switch portion
103
a.
In
FIG. 8
, keyboard switch
100
is shown in a fully depressed position. In a fully depressed position, deformed elastic portion
114
contacts switch portion
103
a.
A computer unit case, mounting a keyboard switch, connects rotatably with a lid
115
which covers key tops
102
in a closing motion.
In
FIG. 9
, as lid
115
closes, rubber sheet
104
and switch sheet
103
, slide relative to support plate
107
(leftward in FIG.
9
), in response to the closing motion. Thus, deformed elastic portion
114
retracts into a storage recessed portion
116
formed under key top
102
.
When deformed elastic portion
114
retracts, key top
102
and cross-link
101
drop due to their own weight provide a low profile. When deformed elastic portion
114
retracts, it does not contact switch portion
103
a.
Retracting elastic portion
114
into storage recessed portion
116
allows elastic portion
114
to return to an original dome shape. Retracting elastic portion
114
into storage recess
116
also removes contact with depressing portion
106
. As a result, conventional key switch
100
allows computer units to reduce overall thickness during the closing of lid
115
. However, the distance between support plate
107
and key top
102
may not be made less than the free-state height of elastic portion
114
thus limiting the minimum thickness of the computer unit.
Furthermore, the need for depressing portion
106
and storage recess
116
, cause each key top
102
and, hence keyboard switch
100
, to be correspondingly larger. Additionally, retracting return spring
114
into storage recess portion
116
requires sliding, thereby requiring the lid
115
mechanism to be larger and more complex. Also, sliding integral rubber sheet
104
and elastic portion
114
require a relatively large force.
A conventional keyboard switch (not shown) allows rubber sheet
104
and integral elastic portion
114
to slide relative to switch sheet
103
. However, this type of conventional keyboard switch has a possibility of malfunction. To limit this possibility, a friction-limiting membrane, for example polyester, has been placed between rubber sheet
104
and switch sheet
103
, thus increasing cost.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a thinner keyboard switch that does not compress a return spring during a closing motion.
It is another object of the present invention to provide a keyboard switch with a return spring means movable to a retracted position.
It is another object of the present invention to provide a keyboard switch with a simplified configuration where a return spring means is integral with a cross-link or a key top.
It is another object of the present invention to provide a keyboard switch, without a friction-limiting membrane, that allows a lidded computer case to open and close with little operational force.
In a closing operation, a keyboard switch actuates a switch sheet and a support plate from a stand-by position to a retracted position and correspondingly narrows a gap between a key top and the switch sheet. In the closing operation, trailing claw pieces cause a cross-link to submerge thereby allowing a switch sheet to accommodate an integrally formed return spring, thus allowing the return spring to retract without being elastically deformed. At the retracted position, the return spring is accommodated inside a retracting hole in the switch sheet.
According to an embodiment of the invention, there is provided a keyboard switch in a lidded device case comprising: a support plate within the device case, a cross-link, mounted between support projections of the support plate and a key top, the cross-link guides the key top up and down, a switch sheet arranged slidably on the support plate avoids contact with the support projections, and provides a switch portion, formed on and actuated by the key top, a return spring attached integrally to the key switch contacts the switch sheet for biasing the lowered key top upwardly, an interlock mechanism for sliding at least one of the switch sheet and the support plate relative to the other from a stand-by position to a retracted position in response to a closing operation of a lid covering the key top and sustains the key top in a lowered state, the keyboard switch for sliding the switch portion actuated by lowering the key top from the stand-by position to the retracted position where the switch portion is not actuated by lowering the key top.
According to another embodiment of the invention there is provided a keyboard switch further comprising: a retracting hole formed in a portion of the switch sheet, and in a retracted position, part of the return spring is accommodated inside the retracting hole.
According to another embodiment of the invention there is provided a keyboard switch further comprising: engagement holes into which trailing claw pieces integrally provided on the cross-link insert, where at least one of the switch sheet and the support plate slides to the retracted position, peripheral edges of the engagement holes contact with the trailing claw pieces to cause the cross-link to submerge and the key top to lower.
According to another embodiment of the invention there is provided a keyboard switch further comprising: a return spring means, the return spring serving as an actuator for the switch portion and upwardly biasing the key top.
According to another embodiment of the invention there is prov
Bradley Paula
Morrison Law Firm
Nguyen Nhung
SMK Corporation
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