Abstract There is disclosed a keyboard in which each of the key contacts consists of a gold-coated wire contact with each end passing through a printed circuit board and soldered to one part of the circuit on the underside of the board and of a gold-coated plate contact with a base part mounted on the printed circuit board by lugs passing through the printed circuit board and soldered to another part of the circuit on the underside of the board and with a part cut in helical form and so deformed in an open spiral to form a resilient raised part directly above the wire contact. Each of the push buttons of the keyboard is circular with diametrical flanges extending outwardly and has a central stem which abuts the central part of the resilient raised part of the plate contact and an annular outer depending ring which surrounds the resilient raised part of the plate contact. On depression, the outer part of the spiral resilient raised part makes initial contact with the wire contact and, after further movement, the inner parts of the spiral resilient raised part make contact with the wire contact.
A keyboard comprising a cover plate; a plurality of push buttons movably mounted within the cover plate; an insulating base plate spaced from the buttons bearing a first set of longitudinally directed fixed contacts on that side of the base plate facing said push buttons, each contact of this set located opposite one of the push buttons; and a plurality of contact plates, each contact plate affixed to said base plate in a position co-operating with a corresponding button and a corresponding one of the first set of contacts; wherein the contact plates each comprises a strip of electrically conducting material having at least one tag securing the strip to the base plate and a resilient part with a free end spaced away from said base plate to engage one said push button at a position normally extending towards the corresponding contact of the first set of contacts to make electrical wiping contact therewith when the push button is moved toward said base plate; and wherein the resilient part of the contact plate comprises an integral part of the contact plate cut out of the contact plate with a helical slot thereby forming a helically shaped conductor which engages said longitudinally directed fixed contact in a wiping action in at least two spaced positions on said helically shaped conductor when said push button is moved toward said base plate.
Claim 2
Dependent Claim
229 words
A keyboard comprising a cover plate; a plurality of push buttons movably mounted within the cover plate; an insulating base plate spaced from the buttons bearing a first set of longitudinally directed fixed contacts on that side of the base plate facing said push buttons, each contact of this set located opposite one of the push buttons; and a plurality of contact plates, each contact plate affixed to said base plate in a position co-operating with a corresponding button and a corresponding one of the first set of contacts; wherein the contact plates each comprises a strip of electrically conducting material having at least one tag securing the strip to the base plate and a resilient part with a free end spaced away from said base plate to engage one said push button at a position normally extending towards the corresponding contact of the first set of contacts to make electrical wiping contact therewith when the push button is moved toward said base plate; and wherein the resilient part of the contact plate comprises an integral part of the contact plate cut out of the contact plate with a helical slot thereby forming a helically shaped conductor which engages said longitudinally directed fixed contact in a wiping action in at least two spaced positions on said helically shaped conductor when said push button is moved toward said base plate.
Claim 3
Dependent Claim
58 words
A keyboard according to claim 1, wherein each button has on its under surface an annular outer depending ring which surrounds the resilient part of the corresponding contact plate and a circular post which is concentric with the depending ring and which is in contact with the free end of the resilient part of the corresponding contact plate.