Electricity: circuit makers and breakers – Multiple circuit control – Multiple switch
Reexamination Certificate
2000-06-27
2001-07-10
Gellner, Michael L. (Department: 2832)
Electricity: circuit makers and breakers
Multiple circuit control
Multiple switch
C200S512000
Reexamination Certificate
active
06259046
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sheet with movable contacts and a sheet switch using the same, which are for use in operating panels of various electronic devices for example.
2. Description of the Related Art
A conventional structure of a sheet with movable contacts and that of a sheet switch are shown in
FIGS. 5 and 6
.
FIG. 5
is a sectional view of the sheet with movable contacts and
FIG. 6
is a sectional view of a sheet switch using the sheet with movable contacts.
In those figures, the sheet with movable contacts is made up of movable contacts
25
formed in a dome shape using metal, a sheet
21
formed by an insulating film, the sheet
21
covering upper surfaces of the movable contacts
25
and having an adhesive
23
applied to a lower surface thereof, and a separator sheet
26
affixed to the lower surface of the sheet
21
to close lower surfaces of the movable contacts
25
, the separator sheet
26
being formed by paper or an insulating film.
The domed upper surfaces of the movable contacts
25
are covered with and fixed to the adhesive
23
which is applied to the lower surface of the sheet
21
. The separator sheet
26
affixed to the lower surface of the sheet
21
is for preventing corrosion of the movable contacts
25
caused by gases contained in air or for preventing the adhesion of foreign matters to the movable contacts, during storage or transport of the sheet. The separator sheet
26
can be peeled off.
A small hole
25
a
is formed in a central portion of each movable contact
25
, and on the lower surface portions of the sheet
21
which surround the small holes
25
a
there are formed sheet exposed portions
21
a
with the adhesive
23
not applied thereto. Since the small hole
25
a
is formed in the central portion of each movable contact
25
, the movable contact comes into contact with a central fixed contact to be described later at an end face of an outer periphery of the small hole formed centrally of the movable contact
25
, so that the contact of the movable contact with the central fixed contact is further ensured.
Since the sheet exposed portions
21
a
free of the adhesive
23
are formed on the lower surface portions of the sheet
21
which surround the small holes
25
a
of the movable contacts
25
, it is possible to prevent the entry of the adhesive
23
onto inner surfaces of the movable contacts from the small holes
25
a.
As shown in the figures, the sheet
21
is provided with sheet exposed portions
21
b
with the adhesive
23
not applied thereto, in the vicinity of lower ends of outer peripheral portions of the movable contacts
25
, whereby it is also possible to prevent the entry of the adhesive
23
from the lower ends of the outer peripheral portions of the movable contacts
25
.
The sheet switch is made up of the above sheet with movable contacts and a circuit board
27
provided on an upper surface thereof with central fixed contacts
29
and outer fixed contacts
28
. In a removed state of the separator sheet
26
from the sheet with movable contacts, the movable contacts
25
are affixed onto the circuit board
27
using the adhesive
23
applied to the lower surface of the sheet
21
in such a manner that lower ends of the outer peripheries of the movable contacts
25
are respectively brought into abutment with the outer fixed contacts
28
and that central portions thereof are opposed to the central fixed contacts
29
.
In the above structure of the sheet switch, when an operating portion of a rubbery or resinous push-button (not shown) disposed above the sheet switch is depressed, the associated movable contact
25
is depressed by a depressing portion formed on a lower surface of the operating portion via the sheet
21
and is inverted, so that its central portion comes into abutment against the associated central fixed contact
29
on the circuit board, whereby the central fixed contact
29
and the associated outer fixed contact
28
on the circuit board
27
are electrically connected with each other. Upon release of the depressing force imposed on the push-button, the central portion of the movable contact
25
is disconnected from the central fixed contact
29
with an elastic restoring force of the movable contact.
In the above conventional structures of the sheet with movable contacts and the sheet switch, however, the movable contacts
25
are covered with and fixed to a single sheet
21
of an insulating film with the adhesive
23
applied to the lower surface of the sheet, so when the sheet with movable contacts is affixed onto the circuit board
27
and when any of the domed movable contacts
25
located near the outer periphery of the sheet
21
is depressed, the air present within the dome of the movable contact is forced out and causes an end portion of the sheet to float, thus giving rise to the problem that dust enters through the floating end portion and causes an incomplete state of contact.
Moreover, the portions of the sheet
21
which surround the domed movable contacts
25
are fixed with the adhesive
23
, so when any of the movable contacts
25
is depressed, the air present within the dome of the depressed movable contact cannot escape anywhere, thus giving rise to the problem that the operation feeling is deteriorated.
Further, it is required that the adhesive
23
be applied to the lower surface of the sheet
21
by such a printing method as masking so as to prevent the adhesive from being applied to the small holes
25
a
formed respectively in the central portions of the movable contacts
25
, thus causing the problem that the production becomes complicated and the manufacturing cost increases.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to solve the above-mentioned problems and provide a structure of a sheet with movable contacts and a structure of a sheet switch using the sheet which, even when a movable contact located near an outer periphery of the sheet is depressed, can prevent floating of the sheet and can thereby prevent the entry of dust, thus affording a high contact reliability, and which can afford a good operation feeling at the time of operation and is easy to fabricate and low in cost.
For solving the above-mentioned problems, according to one aspect of the present invention, there is provided a sheet with movable contacts, comprising a first sheet formed by an insulating film, the first sheet having a plurality of receptacle holes and with adhesives applied respectively to both sides of the first sheet, a plurality of domed, metallic, movable contacts respectively received in the receptacle holes and having central small holes, and a second sheet formed by an insulating film and affixed onto the first sheet so as to cover upper surfaces of the plural movable contacts, wherein the first sheet has connecting slots formed therein for connecting adjacent such receptacle holes with each other, and each of the receptacle holes is larger than each of the small holes formed in the movable contacts and smaller than an external form of each of the movable contacts.
In another aspect of the present invention, outer peripheral end portions in the external form of the movable contacts except the small holes are affixed to the lower surface of the first sheet through the adhesive applied to the first sheet lower surface and are received in the receptacle holes respectively.
In a further aspect of the present invention, a separator sheet whose upper surface has been subjected to a release treatment is affixed to the lower surface of the first sheet so as to be releasable from the first sheet.
In a still further aspect of the present invention there is provided a sheet switch comprising a circuit board having a plurality of fixed contacts; a plurality of domed, metallic, movable contacts each having a small hole formed in a central portion thereof; a first sheet having a plurality of receptacle holes and connecting slots for connecting adjacent such receptacle holes with each other, the r
Iwama Naoya
Yamagata Takeo
Alps Electric Co. Ltd
Brinks Hofer Gilson & Lione
Gellner Michael L.
Nguyen Nhung
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