Electricity: circuit makers and breakers – Electric switch details – Actuators
Reexamination Certificate
2000-12-13
2001-10-09
Bradley, Paula (Department: 2832)
Electricity: circuit makers and breakers
Electric switch details
Actuators
Reexamination Certificate
active
06300583
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a novel collapsible key structure and more particularly to an improved scissors type linkage for the depression key structure to be operated steadily and be assembled easily.
BACKGROUND OF THE INVENTION
In conventional notebook computers, the depression key structure in a keyboard is usually supported by a collapsible mechanism and a rubber.
FIG. 1
shows a typical depression key structure mounted on a base plate
10
. The depression key structure
1
has a key top
11
for receiving external force and a scissors type linkage
12
which has pairs of symmetrical levers to support the depression key structure
1
and to enable the depression key structure
1
being lifted upward or pressed downward. As shown, there is a hollow rubber body
13
located under the depression key structure
1
and between the levers to provide spring energy for lifting the depression key structure
1
after the depression key structure
1
being pressed downward. The touch control circuit for the depression key structure
1
is located on the base plate
10
and under the rubber body
13
(not shown in the figure).
In the following description, only the depression key structure
1
and the collapsible linkage
12
will be shown in the figures and text. The rubber body
13
and touch control circuit will be omitted. Similar components will be marked by similar numerals any way, no matter whether or not they are in the prior arts or belong to this invention.
FIG. 2
shows a conventional collapsible mechanism
12
for the depression key structure
1
. It is located between a bottom side
110
of the key top
11
and the base plate
10
. It has a first lever
121
crossly engaged with a second lever
122
at a pivotal point
123
to form a substantially scissors type linkage. Two sets of such lever linkage are disposed at opposing sides under the key top
11
. The first lever
121
has a first top end
1211
pivotally engaged with a first hub
1101
located under the bottom side
110
and a first bottom end
1212
rotatably and slidably engaged with a third hub
101
located on the base plate
10
. The second lever
122
has a second top end
1221
pivotally and slidably engaged with a second L-shaped flange
1102
located below the bottom side
110
and a second bottom end
1222
pivotally engaged with a fourth hub
102
located on the base plate
10
. The first and the second levers
121
and
122
thus form a scissors type linkage
12
that may be moved up or down under external force. The first hub
1101
and fourth hub
102
are located fixedly on a vertical dot line L.
When the key top
11
of the depression key structure
1
subjects to a downward or uplift pressure, the first top end
1211
and the second bottom end
1222
can move pivotally respectively in the first and fourth hub
1101
and
102
, while the second top end
1221
and first bottom end
1212
are rotational and slidable respectively on the second flange
1102
and third hub
101
. Although this structure may allow the depression key structure
1
to be lifted or lowered steadily, yet it is difficult to be manufactured and assembled. In addition, well performance of the vertical alignment of the first hub
1101
and the fourth hub
102
needs good precision in assembly. Or, a small deviation upon such alignment will create a substantial amount of lever deformation and thus make hard to fit the first top end
1211
and the second bottom end
1222
into the hubs
1101
and
102
, respectively.
Furthermore, as the notebook computer is small sized and the lever
121
and
122
are generally made by plastics in thin and elongating shapes, the deformation under any possible external force during assembly could often break or rupture the levers, particularly at the force concentration points thereof at both ends of the lever or in the middle pivotal point thereof. Inevitably, such a disadvantage will drag down the production efficiency as well as the yield of the keyboard. Also, assembly and disassembly related to the depression key structure of a notebook computer is difficult. Moreover, repairs and maintenance work of such key structure are definitely time consuming.
FIG. 3
shows another conventional collapsible mechanism for depression key structure. Comparing with the one shown in
FIG. 2
, the main differences in between are the engagement styles for the first top end
1211
and the second bottom end
1222
. A L-shaped first flange
1101
replaces the hub and a rotatable and slidable fourth hub
102
are used to replace the hub used in FIG.
2
. Thus, all four ends of the fist and the second levers
121
and
122
are rotatable and slidable. As shown in this embodiment, there is no fixed vertical line alignment needed. Assembly and disassembly is also easier, by comparing with the aforesaid structure. Deformation of the levers is believed to be less severe and may reduce the possibility of breaking or rupture upon the levers.
However, due to no need of the fixed vertical line alignment upon the respective pivotal point, the levers could then move sideward. The up and down motion of the depression key structure
1
is thus less stable. Therefore, how to get a supporting mechanism of the depression key structure that enables the depression key structure
1
to move up or down steadily and may be assembled or disassembled easily is still an issue begging for improvement.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a novel collapsible mechanism for a depression key structure that may offer steady operation of the depression key structure and may also be assembled and disassembled easily.
It is another object of this invention to provide a collapsible mechanism that offers a rotatable and slidable constraint means for the levers so that the depression key structure may be moved up or down steadily and controllably without drifting sideward.
The collapsible mechanism of this invention includes a key top, a base plate and a scissors type linkage to support the key top for up and down movement above the base plate. The scissors type linkage has a first lever pivotally engaged with a second lever at a middle pivotal point. The first lever has a first top end pivotally engaging with a first hub located under the key top and a first bottom end rotatable and slidable in a third hub located on the base plate. The second lever has a second top end rotatable and slidable in an L-shape flange located under the key top and a second bottom end rotatable and slidable in a rotatable and slidable constraint means.
The rotatable and slidable constraint means includes a bordering rail mounted on the base plate, and a first engaging pin and a second engaging pin located at the second bottom end. The bordering rail has a horizontal first sliding surface distant from the pivotal point for the first engaging pin to slide thereon, and a vertical second sliding surface facing the pivotal point for the second engaging pin to slide thereon.
Two pairs of symmetrical scissors type levers are used to support a depression key structure.
The bordering rail may be a “L”-shaped member with the first sliding surface being flat, smooth and horizontally located under the horizontal flange facing the base plate and the second sliding surface being smooth and vertically located at a lateral side facing the pivotal point.
In another aspect of the present invention, the bordering rail may be a rectangular member mounted on the base plate with a vertical smooth outward side wall serving as the second sliding surface and a horizontal smooth bottom surface under the top wall serving as the first slide surface.
According to the present invention, the second sliding surface may have a curvature or be a flat surface (with an infinite curvature).
In yet another aspect of the present invention, a third sliding surface may be formed on base plate surface to couple with the second sliding surface for limiting the moving path of the first engaging pin.
REFERENCES:
patent: 4580022 (1986-04-01), Oelsch et al.
p
Bradley Paula
Darfon Electronics Corp.
Dougherty & Troxell
Nguyen Nhung
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