Northern Telecom Limited

Geoffrey A Collar

Pak-Jong Chu

John S Moss

Paul Douglas McDonald

Anthony J Langenberg

Brian E Voss

A telephone hook switch uses an elastomeric member as the contact making member. A hook switch has a pivotally mounted actuating member having two levers extending in opposite directions, one on each side of the pivot axis. One lever is moved by the positioning, and removal, of a handset, the actuating member being biased to a particular pivotal direction. The other lever presses on a deformable projection in the elastomeric member. Depression of the projection causes an electrically conducting layer to move into contact with contact areas of a switch position on a printed circuit board.

Telephone hook switch with elastomeric contact member

A circuit pattern on a circuit board, as used in telecommunications systems and other electrical apparatus, often has contact positions for switches, such as pushbutton switches, and for other purposes. The normal copper circuit pattern is covered at the contact positions to give improved contact conditions. Carbon ink has been proposed by obtaining the necessary high level of alignment of carbon ink with the copper pattern at contact positions is difficult as such contact positions have very close members. The invention proposes contact positions having closely spaced inter-digital contact members, in which the circuit pattern extends to and stops at the peripheral region of a contact position, the contact members being of carbon ink and overlapping conductors of the circuit pattern at the peripheral region.

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Ottawa, Canada

Geoffrey A Collar