EP0087918A1
Expired / Lapsed
EP
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Keyboard Switch
Assignee: Sinclair Research Ltd
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Filing: 1983-02-23
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Granted: —
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Expires: 2003-02-23
Abstract
Abstract keyboard switch (40) includes a portion of a sheet (21) of moulded silicone rubber having raised sides (22, 22') supporting a key button (23). A projection (41) on one of the raised sides (22') bears on membrane switch electrical contacts (42) when the key button (23) is depressed. One raised side (22') has a greater length and thickness than the other side (22) and includes a ridge (27) at the base so as to provide a cantilever action pivoted at the ridge when the switch is operated. The cantilevered side (22') provides a positive locating movement and the more resilient side (22) provides a "snap" action to the switch. In another embodiment (not shown) the electrical contacts are positioned above a surface having a recess with a central pip in the recess; when the key button is depressed, the electrical contacts are compressed between the pip and the bearing portion of the key button (or associated projection).
Inventors
- 👤 David Conner Southward
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 19:18
CPC Classifications
H; H01; H01H; H01H13/00; H01H13/70; H01H13/702; H01H13/705; H01H2215/00; H01H2215/004; H01H2215/022; H01H2221/00; H01H2221/008; H01H2221/016
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
83 words
A keyboard switch comprising a key actuating member having a key button and supporting portions on different sides of the key button, and electrical contact means arranged to change their state of conduction in response to pressure on and consequent relative movement of the key button, one of the supporting portions being relatively rigid thereby providing a cantilever effect to movement of the key button and another of the supporting portions being relatively resilient thereby providing a restoring force to the key button.
Claim 2
Dependent Claim
83 words
A keyboard switch comprising a key actuating member having a key button and supporting portions on different sides of the key button, and electrical contact means arranged to change their state of conduction in response to pressure on and consequent relative movement of the key button, one of the supporting portions being relatively rigid thereby providing a cantilever effect to movement of the key button and another of the supporting portions being relatively resilient thereby providing a restoring force to the key button.
Claim 3
Dependent Claim
31 words
A keyboard switch according to claim 1, wherein the rigid supporting portion comprises a side of the key actuating member which is longer than the side forming the resilient supporting portion.
Claim 4
Dependent Claim
23 words
A keyboard switch according to claim 1 or 2, wherein the rigid supporting portion has a greater thickness than the resilient supporting portion.
Claim 5
Dependent Claim
32 words
A keyboard switch according to claim 1, 2 or 3 wherein the rigid supporting portion includes a ridge of lesser thickness so as to provide a pivoting point for the cantilever effect.
Claim 6
Dependent Claim
26 words
A keyboard switch according to any one of the preceding claims, wherein the key button and supporting portions are integral and made of a resilient material.
Claim 7
Dependent Claim
32 words
A keyboard switch according to claim 5, wherein the integral key actuating member is part of a sheet of resilient material forming a keyboard with a plurality of similar key actuating members.
Claim 8
Dependent Claim
45 words
A keyboard switch according to any one of the preceding claims, wherein the key button includes a conductive portion and the electrical contact means comprises electrical contacts positioned so that pressure on the key button brings the conductive portion to bear on the electrical contacts.
Claim 9
Dependent Claim
63 words
A keyboard switch according to any one of claims 1 to 6, wherein the electrical contact means includes two contact portions separated by a membrane having an aperture therein, such that in an unstressed state the contact portions are held apart at the aperture but when urged by pressure on the key actuating member the contact portions are brought together within the aperture.
Claim 10
Dependent Claim
65 words
A keyboard switch according to claim 8, wherein the membrane of the electrical contact means is located on a surface having a recess aligned with the key actuating member and a projection in the recess aligned with the membrane aperture, so that when urged by pressure on the key actuating member the contact portions are brought together between the key actuating member and the projection.
Claim 11
Dependent Claim
124 words
A keyboard switch comprising a key actuating member and electrical contact means arranged to change their state of conduction in response to pressure on and consequent relative movement of the key actuating member, the electrical contact means including two contact portions separated by a membrane, the membrane having an aperture such that in an unstressed state the contact portions are held apart at the aperture. but when urged by the key actuating member the contact portions are brought together within the aperture, the membrane being located on a surface having a recess aligned with the key actuating member and a projection within the recess aligned with the membrane aperture, that the contact portions are brought together between the key actuating member and the projection.
Claim 12
Dependent Claim
124 words
A keyboard switch comprising a key actuating member and electrical contact means arranged to change their state of conduction in response to pressure on and consequent relative movement of the key actuating member, the electrical contact means including two contact portions separated by a membrane, the membrane having an aperture such that in an unstressed state the contact portions are held apart at the aperture. but when urged by the key actuating member the contact portions are brought together within the aperture, the membrane being located on a surface having a recess aligned with the key actuating member and a projection within the recess aligned with the membrane aperture, that the contact portions are brought together between the key actuating member and the projection.
References Cited (Backward Citations)
US3932722A
Cited
FR2457006A1
Cited
US4129758A
Cited
FR2442502A1
Cited
GB2039417A
Cited
GB2077464A
Cited
DE3044414A1
Cited
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