Computer graphics processing and selective visual display system – Display peripheral interface input device – Cursor mark position control device
Reexamination Certificate
2000-02-04
2002-09-10
Shalwala, Bipin (Department: 2673)
Computer graphics processing and selective visual display system
Display peripheral interface input device
Cursor mark position control device
C345S156000, C345S168000, C200S302100, C200S302200, C200S302300
Reexamination Certificate
active
06448957
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The pre sent invention relates to a pointing stick device, and more particularly, to a waterproof pointing device of a keyboard.
2. Description of the Prior Art
A pointing device is usually installed on the keyboard of a notebook computer and provides a means of inputting cursor control signals. It is often installed on the keyboard chassis board with a hole. There are often gaps between the pointing device and the chassis board; therefore, if not careful, liquids, such as water or coffee may accidentally spill on the keyboard and leak into the interior of the keyboard through these gaps. This will adversely affect the functioning of the pointing device and further damage the mainboard installed below the keyboard of the notebook computer.
The structure of a waterproof pointing device according to the prior art is illustrated in FIG.
1
and FIG.
2
.
FIG. 1
is a sectional diagram of a pointing device
10
according to prior art.
FIG. 2
is an exploded diagram of the pointing device
10
shown in FIG.
1
. The pointing device
10
is installed on a chassis board
12
with a hole
13
. The pointing device comprises a metallic base plate
24
mounted on the bottom side of the chassis board
12
by screws
15
, a plastic pedestal
22
mounted between the chassis board
12
and the base plate
24
, a clamping unit
28
for clamping the plastic pedestal
22
on the base plate
24
, a square control bar
20
vertically fixed on the plastic pedestal
22
and protruding through the hole
13
of the chassis board
12
, a rubber cap
14
installed on the top of the control bar
20
, and an adapter
16
installed between the rubber cap
14
and the control bar
20
. There is also a rubber-like backing
19
adherent to the back of the base plate
24
and a square shaped rubber-like sponge
18
installed exterior to the plastic pedestal
22
on the base plate
24
. The rubber-like sponge
18
is clamped between the chassis board
12
and the base plate
24
to prevent leakage of liquid. The pointing device
10
further comprises four sensors
26
individually installed in four directions near the bottom end of the control bar
20
for sensing the movement of the control bar and generating the corresponding sensing signals.
Because the plastic pedestal
22
is fixed with the clamping unit
28
but does not form a waterproof seal, the rubber-like sponge
18
cannot be placed between the chassis and the clamping unit
28
. Instead, rubber-like sponge
18
must be placed at the periphery of the plastic pedestal
22
. Therefore, it is imperative that the area of the base plate
24
be large enough to accommodate the rubber-like sponge
18
. Because the pointing device
10
is installed on the chassis board of the keyboard and the base plate is protruding outward from the chassis board, space must be allowed under the keyboard for both the mainframe as well as the base plate
24
. Space for the mainframe is severely limited thus increasing the difficulty of design and assembly. Also, in the above mentioned waterproof pointing device of the prior art, rubber-like sponge
18
can only be used temporarily to prevent liquid from leaking into the keyboard. This is due in part to the fact that the liquid will accumulate in the interior of the rubber-like sponge
18
thus leading to rusting of the metal base plate
24
. Eventually, liquid will inevitably leak onto the mainboard and cause damage. The sensor
26
at the bottom of control bar
20
will also be damaged from this liquid.
SUMMARY OF THE INVENTION
It is therefore a primary objective of the present invention to provide a waterproof pointing device of a keyboard to solve the above mentioned problem.
In a preferred embodiment, the present invention provides a pointing device of a keyboard which comprises a chassis board for mounting a plurality of keys, the chassis board comprising a hole positioned at its center approximate for mounting the pointing device, the pointing device comprising:
a pedestal installed below the chassis board under the hole of the chassis board;
an elastic pad mounted between the chassis board and the pedestal with a hole positioned below the hole of the chassis board; and
a control bar vertically fixed to the pedestal and protruding through the holes of the elastic pad and the chassis board;
wherein the elastic pad is tightly clamped between the pedestal and the chassis board for preventing liquid above the chassis board from leaking into the space below the chassis board and the pedestal through the hole of the chassis board.
It is an advantage of the present invention that the elastic pad can be tightly clamped between the chassis board and the plastic pedestal for preventing liquid from leaking through the hole of the chassis board into the base plate. Also, no liquid will accumulate on the base plate or the sensors at the bottom end of the control bar and, therefore, the main board below the keyboard will not be subjected to damage by liquid. There are many designs for the elastic pad of the pointing device of the present invention. The elastic pad is installed on top side of the plastic pedestal and only occupies space within the plastic pedestal on the base plate. The base plate may be reduced in size thus further facilitating the installation of the pointing device within a limited space.
This and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiment which is illustrated in the various figures and drawings.
REFERENCES:
patent: 4994669 (1991-02-01), Stern
patent: 5541622 (1996-07-01), Engle et al.
patent: 5694123 (1997-12-01), Selker et al.
patent: 6141667 (2000-10-01), Duff
patent: 6219038 (2001-04-01), Cho
patent: 6239391 (2001-05-01), Nishijima et al.
Darfon Electronics Corp.
Hsu Winston
Kovalick Vincent E.
Shalwala Bipin
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