Keyboard switch assembly with conductive plastic contactor and actuator spring sleeve biasing means

Claim 2

A switch comprising a key, a key stem extending therefrom, a first spring positioned below said key and about said stem, a contactor positioned and movable about said stem, a member having a hole therethrough for the passage of the stem, said member positioned below said contactor and said member having at least two electrical contacts about said hole, support means positioned below said member for slidably supporting the stem therein, and a second spring positioned on the support means and having a portion extending through said hole to maintain said contactor above said contacts.

Claim 3

A switch according to claim 1 in which he contactor is a conductive plastic.

Claim 4

An array according to claim 2 in which the conductive plastic is filled with carbon black.

Claim 5

A switch according to claim 2 in which he conductive plastic comprises a conformable plastic loaded with metal particles.

Claim 6

An array according to claim 4 in which the conductive plastic is filled with carbon black.

Claim 7

A switch according to claim 4 in which the metal comprises 10 to 80 volume percent of the conductive plastic.

Claim 8

A swiTch according to claim 6 in which the conductive plastic has a volume resistivity less than 0.01 ohm centimeters.

Claim 9

A switch according to claim 7 in which the conductive plastic exhibits less than a 1 ohm per cm3 change in resistance with pressure applied thereto by key depression.

Claim 10

An encoded switch array comprising a circuit board having a plurality of holes formed therethrough, electrical contacts supported by and positioned about at least some of said holes of said circuit board, a base plate having a plurality of bores in alignment with the plurality of holes having the electrical contacts positioned about them, a plurality of keys, key stems attached to said keys and extending through said holes having contacts positioned about them, a contactor positioned about each of the stems and adapted to move about said stems, first means for holding each of said contactors above said contacts, second means for pressing each of said contactors against said contacts upon the depression of said keys, said circuit board having a wiring pattern thereon coupled to said electrical contacts, and each stem adapted to slidably move within a different one of said bores, and wherein said first means comprises a plurality of springs which are positioned on said base plate and which have a portion which extends through said holes in said board to hold said contactors above said electrical contacts.

Claim 11

An encoded switch array comprising a circuit board having a plurality of holes formed therethrough, electrical contacts supported by and positioned about at least some of said holes of said circuit board, a base plate having a plurality of bores in alignment with the plurality of holes having the electrical contacts positioned about them, a plurality of keys, key stems attached to said keys and extending through said holes having contacts positioned about them, a contactor positioned about each of the stems and adapted to move about said stems, first means for holding each of said contactors above said contacts, second means for pressing each of said contactors against said contacts upon the depression of said keys, said circuit board having a wiring pattern thereon coupled to said electrical contacts, and each stem adapted to slidably move within a different one of said bores, and wherein said first means comprises a plurality of springs which are positioned on said base plate and which have a portion which extends through said holes in said board to hold said contactors above said electrical contacts.

Claim 12

An array according to claim 9 in which said second means comprising a plurality of springs each having a portion positioned to press said contactor against said contacts and wherein the springs of each plurality of springs are constructed to force the keys back to their original position after they are released following depression.

Claim 13

A switch comprising a circuit board having at least one electrically conductive contact provided on one surface thereof, a conductive plastic contactor for electrically engaging said contact, first plastic insulator means extending between the contact and the conductive plastic contactor for positioning the conductive plastic contactor out of engagement with said contact, depressible key means supported by the board for forcing said contactor to engage said contact, insulator cover means positioned in physical contact with said contactor and spring means positioned in physical contact with said cover means and said key means to provide resistance to key means depression.

Claim 14

A switch comprising a circuit board having at least one electrically conductive contact provided on one surface thereof, a conductive plastic contactor for electrically engaging said contact, first plastic insulator means extending between the contact and the conductive plastic contactor for positioning the conductive plastic contactor out of engagement with said contact, depressible key means supported by the board for forcing said contactor to engage said contact, insulator cover means positioned in physical contact with said contactor and spring means positioned in physical contact with said cover means and said key means to provide resistance to key means depression.

Claim 15

A switch according to claim 11 in which the conductive plastic contactor is filled with carbon black.

Claim 16

A switch according to claim 11 in which the cover is a plastic film.

Claim 17

A switch according to claim 11 in which the conductive plastic contactor has a resistivity less than 0.1 ohm centimeters.

Claim 18

A switch according to claim 14 in which the conductive plastic exhibits less than a 0.1 ohm per cm3 change in resistance with pressure applied thereto by key depression.

Claim 19

A switch comprising a key, a key stem extending therefrom, a first spring positioned below said key and about said stem, a member having a hole therethrough for the passage of the stem, said member positioned below said contactor and said member having electrical contact means about said hole, support means positioned below said member for slidably supporting the stem therein, and a second spring positioned on the support means and having a portion extending through said hole to maintain said contactor above said contact means.

Claim 20

A switch comprising a key, a key stem extending therefrom, a first spring positioned below said key and about said stem, a member having a hole therethrough for the passage of the stem, said member positioned below said contactor and said member having electrical contact means about said hole, support means positioned below said member for slidably supporting the stem therein, and a second spring positioned on the support means and having a portion extending through said hole to maintain said contactor above said contact means.