Typewriting machines – Key-board or key lever-actuating mechanism
Reexamination Certificate
1999-07-02
2001-08-14
Hilten, John S. (Department: 2854)
Typewriting machines
Key-board or key lever-actuating mechanism
C400S496000
Reexamination Certificate
active
06273623
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a keyboard water-resistant structure, in particular, to a water-resistant structure for keyboard assemblies with enhanced water-resistant ability.
DESCRIPTION OF THE PRIOR ART
FIG. 1
is an exploded perspective view showing the structure of a keyboard assembly
1
. The keyboard assembly
1
comprises a keyboard hood
11
, a plurality of key caps
19
, an elastic water-resistant sheet
15
, a circuit membrane
14
, a metal plate
13
, and a keyboard base
12
. The water-resistant sheet
15
is made of rubber, and an endless flange
151
is integrally formed on its peripheral rim. Furthermore, plural elastic protrusions
155
are formed on the elastic water-resistant sheet
15
, and plural through holes
157
are formed in the elastic water-resistant sheet
15
.
FIG. 2
is a cross-sectional view showing the internal structure of the fabricated keyboard assembly
1
shown in FIG.
1
. The metal plate
13
is affixed on the keyboard hood
11
by means of bolts
17
and the keyboard base
12
is affixed on the keyboard hood
11
with the aid of bolts
18
. The water-resistant sheet
15
and the circuit membrane
14
are disposed therebetween.
FIGS. 3A
,
3
B and
FIG. 4
are enlarged cross-sectional views respectively showing the portions Z
1
, Z
2
, and Z
3
in FIG.
2
.
As shown in
FIGS. 3A and 3B
, a downward-extending flange
111
is integrally formed with the keyboard hood
11
.
The metal plate
13
strongly urges the water-resistant sheet
15
toward the flange
111
while the keyboard base
12
is brought to connect with the keyboard hood
11
by means of the bolts
18
. Compared with the water-resistant sheet
15
, the downward-extending flange
111
is rigid. Therefore, deformation of the water-resistant sheet
15
, which is induced by tight contact between the downward-extending flange
111
and the water-resistant sheet
15
, primarily takes place circular flange
153
side. Due to that fastening force is normal to the water-resistant sheet
15
; it will cause irregular wrapping of the water-resistant sheet
15
at the portion near the downward-extending flange
111
. For that reason, there exists a possibility that water enters the keyboard assembly from the gaps caused by irregular wrapping of the water-resistant sheet
15
. Accordingly, the water-resistant sheet
15
will not function as a water-resistant member any more, and it is unable to prevent water from entering the keyboard assembly.
As shown in
FIG. 4
, a downward-extending flange
112
with a deep hole
115
formed therein is integrally formed with the keyboard
11
. A circular flange
153
facing the downward-extending flange
112
is formed on the water-resistant sheet
15
. When the keyboard
11
and the keyboard base
12
are fastened together, the downward-extending flange
112
is brought to strongly urge the circular flange
153
that is upheld by the metal plate
13
. As described above, the bolts
17
are used for fastening the metal plate
13
with the keyboard hood
11
. The fastening forces exerted by the bolts
17
are always normal to the water-resistant sheet
15
. Compared with the circular flange
153
, the downward-extending flange
112
is rigid. Therefore, deformation induced by tight contact between them will primarily take place on the circular flange
153
side.
Therefore, the fastening force exerted by the bolts
17
, which is normal to the water-resistant sheet
15
, will cause irregular wrapping of the water-resistant sheet
15
at the portion surrounding the bolts
17
. For that reason, it is possible that water enters the keyboard assembly from the gaps caused by the irregular wrapping of the water-resistant sheet
15
.
Furthermore, as shown in
FIGS. 3A and 3B
, it is essential to keep a tight contact between the endless flange
151
and the downward-extending flange
111
so as to prevent water from entering the keyboard assembly. Therefore, a high accuracy in their dimension is required. The same situation happens in the portion of the keyboard assembly shown in FIG.
4
.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a keyboard assembly with a water-resistant structure that can strongly prevent water from entering the keyboard assembly.
The keyboard assembly according to this invention is used for inputting data into a computer via keys. The keyboard assembly has a keyboard hood, on which keys are disposed; a circuit membrane disposed within the keyboard assembly, for being actuated by the keys disposed on the keyboard hood; an elastic water-resistant sheet disposed between the keys and the circuit membrane; and a keyboard base fastened to the keyboard hood so as to enclose the water-resistant sheet and the circuit membrane therebetween. The keyboard assembly is characterized in that: the keyboard hood is provided with a plurality of first slant wall extending toward the keyboard base; the keyboard base is provided with a plurality of second slant wall extending toward the keyboard hood and in parallel with the first slant wall; and the elastic water-resistant sheet is provided with upward-extending slant verges sandwiched between the first and the second slant wall so as to form a water-resistant structure when the keyboard assembly has been fabricated.
Furthermore, the keyboard assembly is characterized in that: the keyboard base is fastened to the keyboard hood by fastening screws passing through the through holes formed in the centers of the bosses of the keyboard base; the fastening screws are screwed into holes formed in protrusion portions
219
formed together with the keyboard hood; and step-shaped sections are formed on the tip ends of the protrusion portions
219
so as to form tight water-proof seal between the keyboard hood and the base when the keyboard assembly has been fabricated.
Furthermore, the keyboard assembly is characterized in that: plural pairs of first parallel ribs are formed on the base; the elastic water-resistant sheet is in a shape that it can be deeply embedded into the first slots formed between each pair of the first ribs and can cover the ribs and the keyboard base when the keyboard assembly has been fabricated; and a plurality of second ribs are formed on the keyboard hood, which are deeply embedded into the second slots of the water-resistant sheet when the keyboard assembly has been fabricated.
Furthermore, the keyboard assembly is characterized in that: plural pairs of third ribs are formed on the keyboard hood; a plurality of fourth ribs are formed on the water-resistant sheet; the fourth ribs are in a shape that they can be deeply embedded into the slot formed in each pair of third ribs when the keyboard assembly has been fabricated.
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patent: 4366463 (1982-12-01), Barker
patent: 4396830 (1983-08-01), Isozaki et al.
patent: 4421966 (1983-12-01), Pounds
patent: 5111364 (1992-05-01), Yohimoto et al.
patent: 5114790 (1992-05-01), Corbett
patent: 5180237 (1993-01-01), Chen
patent: 5612692 (1997-03-01), Dugas et al.
patent: 5697718 (1997-12-01), Erler et la.
patent: 5810491 (1998-09-01), Muller et al.
patent: 3808567 (1989-09-01), None
patent: 0104956 (1984-04-01), None
Acer Peripherals Inc.
Hilten John S.
Ladas & Parry
Nguyen Anthony H.
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