Typewriting machines – Key-board or key lever-actuating mechanism – Key-cap or key-stem structure
Reexamination Certificate
2003-04-10
2004-10-19
Colilla, Daniel J. (Department: 2854)
Typewriting machines
Key-board or key lever-actuating mechanism
Key-cap or key-stem structure
C400S489000, C400S491000, C400S491200, C400S495000, C400S496000, C200S237000, C200S341000, C200S345000
Reexamination Certificate
active
06805507
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a keyboard device, more particularly to a keyboard device that can be produced through a simplified fabrication process and that can be easily assembled.
2. Description of the Related Art
FIG. 1
illustrates a conventional keyboard device that includes a substrate
16
, a membrane circuit
15
, and a plurality of key units (only one is shown). The substrate
16
is subjected to first and second punching operations (see
FIG. 2
) so as to form the substrate
16
with a plurality of rectangular punched holes
160
, and a plurality of positioning lugs
161
. Each of the positioning lugs
161
extends upwardly from one side of a corresponding one of the punched holes
160
, and is formed with a positioning hole
162
therethrough. The membrane circuit
15
is provided on the substrate
16
and is formed with a plurality of apertures
151
registered with the punched holes
160
in the substrate
16
to permit upward extension of the positioning lugs
161
. Each key unit includes an upright biasing member
14
mounted on a film layer
141
that is provided on the membrane circuit
15
and that is formed with a plurality of through holes
142
registered with the apertures
151
in the membrane circuit
15
to permit upward extension of the positioning lugs
161
, a base plate
13
disposed on the film layer
141
and formed with an opening
133
to permit upward extension of the biasing member
14
and opposite positioning protrusions
132
on opposite ends
131
to engage the corresponding positioning holes
162
such that the base plate
13
is positioned on the substrate
16
, a key cap
11
disposed above and abutting against the biasing member
14
, and a foldable retaining member
12
provided between the base plate
13
and the key cap
11
for retaining the key cap
11
on the base plate
13
.
The following are some of the drawbacks of the conventional keyboard device:
1. The substrate
16
must be subjected to the first and second punching operations such that the fabrication process for the conventional keyboard device is relatively complicated. Moreover, referring to
FIG. 2
, during the first punching operation, black areas (A, B) have to be removed from the substrate
16
such that punched scraps generated during the first punching operation result in waste of material.
2. Since the structural strength of each positioning lug
161
is weakened during the first punching operation, deformation of the positioning lugs
161
resulting from the second punching operation may occur. Consequently, accurate engagement between the positioning lugs
161
on the substrate
16
and the positioning protrusions
132
of the base plate
13
cannot be ensured.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide a keyboard device that can be produced through a simplified fabrication process and that can be easily assembled.
According to the present invention, a keyboard device comprises:
a substrate subjected to a single punching operation so as to form the substrate with a plurality of punched holes, each of which has a first side and a plurality of positioning members, each of which includes an upright first wall portion that extends from the first side of a corresponding one of the punched holes, and a second wall portion that is connected to the first wall portion and that extends parallel to the substrate such that the first and second wall portions cooperate to confine a positioning groove;
a membrane circuit provided on the substrate and formed with a plurality of through holes registered with the punched holes in the substrate, respectively, the through holes permitting the positioning members of the substrate to extend upwardly therethrough, the membrane circuit being provided with a plurality of electrical contacts; and
a plurality of key units disposed on the membrane circuit and assembled on the substrate, each of the key units including
an upright biasing member supported on the membrane circuit and having an actuator registered with a corresponding one of the electrical contacts,
a base plate disposed on the membrane circuit and formed with an opening to permit extension of the biasing member therethrough, the base plate having opposite ends, each of which is formed with an outwardly extending positioning block engaged in the positioning groove confined by a corresponding one of the positioning members of the substrate such that the base plate is positioned on the substrate,
a key cap disposed above the base plate, and
a foldable retaining member provided between the base plate and the key cap for retaining the key cap on the base plate such that the key cap is movable toward and away from the base plate,
the biasing member providing a biasing force for moving the key cap away from the base plate.
REFERENCES:
patent: 6150624 (2000-11-01), Yao
patent: 6179497 (2001-01-01), Hu
patent: 6194677 (2001-02-01), Li
patent: 6288353 (2001-09-01), Chiang
Colilla Daniel J.
Ostrolenk Faber Gerb & Soffen, LLP
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