Electricity: circuit makers and breakers – Snap – Double snap
Reexamination Certificate
2002-09-09
2004-03-23
Donovan, Lincoln (Department: 2832)
Electricity: circuit makers and breakers
Snap
Double snap
C200S512000, C200S517000
Reexamination Certificate
active
06710276
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a contact device for a keyswitch used in an electronic instrument such as portable telephone, and more particularly relates to a contact device in a key sheet module used in a keyswitch operated by a key top.
FIG. 10
is a plan view showing a conventional key sheet module,
FIG. 11
is an enlarged sectional view taken along a line XI—XI of
FIG. 10
, and
FIG. 12
is a plan view of fixed contacts.
The key sheet module
81
comprises a substrate
82
, and a plurality of keyswitches
83
provided on the substrate
82
.
Referring to
FIGS. 11 and 12
, the keyswitch
83
comprises a first circular fixed contact
86
secured on the substrate
82
, and a second annular fixed contact
87
provided around the first fixed contact
86
, and a movable contact
85
having a semispherical shape and mounted on the second fixed contact
87
. The first fixed contact
86
is connected to a circuit pattern
88
provided on the underside of the substrate
82
by a connecting pipe
82
a
secured to a wall of a through-hole formed in the substrate
82
. The second fixed contact
87
is connected to a circuit pattern
89
provided on the upper surface of the substrate
82
. An adhesive sheet
84
is adhered to the substrate
82
to hold the movable contact
85
each of the keyswitches
83
.
When the movable contact
85
is pressed by a key (not shown), the contact
85
contacts with the first fixed contact
86
. Thus, the first and second fixed contacts
86
and
87
are connected with each other.
In the conventional keyswitch, since circuit patterns
88
and
89
are provided on both surfaces of the substrate
82
, the manufacturing cost increases. Further, there are two different manufacturing steps comprising the soldering on the circuit patterns
88
and
89
and the adhering of the adhesive sheet
84
, which increases further the manufacturing cost.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a contact device which may be manufactured at a low cost.
According to the present invention, there is provided a keyswitch comprising a circuit substrate, a first fixed contact mounted on an upper surface of the circuit substrate, a second fixed contact mounted on the upper surface of the circuit substrate around the first fixed contact, a movable contact having a semicircular sectional shape and mounted on the second fixed contact, terminal electrodes provided on an underside of the circuit substrate and connected to the first and second fixed contacts respectively, a spacer mounted on the circuit substrate so as to surround the movable contact, and a cover mounted on the spacer to cover the movable contact.
The movable contact has a plurality of feet so as to hold the movable contact, and the second fixed contact has an opening. The first fixed contact is connected to the terminal electrode by a conductive pattern formed on the circuit substrate in the opening.
REFERENCES:
patent: 3996429 (1976-12-01), Chu et al.
patent: 3996547 (1976-12-01), Kinjo
patent: 4319099 (1982-03-01), Asher
patent: 4768284 (1988-09-01), De Filippis et al.
patent: 4913285 (1990-04-01), Tsutsumi et al.
patent: 4933522 (1990-06-01), Celander
patent: 6133536 (2000-10-01), Hunag et al.
patent: 2000-348566 (2000-12-01), None
Citizen Electronics Co. Ltd.
Dennison Schultz Dougherty & MacDonald
Donovan Lincoln
Lee K.
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