Pushbutton cantilevered leaf spring contact switch assembly for keyboard type switch arrays |
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| 申请号 | US3746816D | 申请日 | 1971-05-18 | 公开(公告)号 | US3746816A | 公开(公告)日 | 1973-07-17 |
| 申请人 | UNIVERSAL TECHNOLOGY; | 发明人 | BRADY J; | ||||
| 摘要 | A low profile electromechanical keyboard switch, displaying very low electrical bounce. The switch key top bears against a generally cylindrical plunger which has a depressed flat portion on its side engageable with a tactile ball biased by a spring nested in the switch housing. Upon application of a force to the key top which exceeds a threshold value, the tactile ball is displaced from the flat and over the shoulder defined between the depressed flat and the cylindrical portion of the plunger. Sudden, positive movement of the plunger against an underlying contact leaf ensues. The contact leaf is branched into multiple contact fingers, and arranged with respect to an underlying contact plate so that wiping contact occurs between fingers and plate. The switch housing is configured to carry sufficient diodes and resistors to assure full control and encoding functions in the keyboard in which such switch may be mounted. | ||||||
| 权利要求 | 1. A low proFile keyboard switch comprising in combination: a. a switch housing; b. a contact plate mounted in said housing; c. a contact leaf supported in cantilevered fashion in said housing, said leaf being positioned approximately in parallel spaced relationship to said plate, said leaf comprising a base portion, a branch portion extending from said base portion, and multiple contact fingers connected to said branch portion and cantilevered over said contact plate; d. plunger means adapted to bear upon said contact fingers and displace them into contact with said contact plate to close said switch; e. a key top engageable with the top of said plunger means; and f. means for connecting said leaf and plate to an electrical circuit for control by said switch. 2. Apparatus in accordance with claim 1 wherein said plunger means carries a depressed portion on a face thereof parallel to the direction of said displacement, and wherein said switch further includes a tactile ball and a tactile spring nested in said housing for biasing said ball against said plunger face, said spring and ball being nested at a position such that when the plunger is in an undepressed position the tactile ball rests in said depressed portion and thereby provides a resistive force to displacement of said plunger, sufficient force upon said plunger acting to move said plunger and displace said ball outwardly from said depressed portion whereby to suddenly reduce the said resistive force and provide tactile indication to the operator of movement of said plunger. 3. Apparatus in accordance with claim 2 wherein said base and finger portions of said leaf surround and define an opening in said leaf, an opening being present in said contact plate, and a plunger support passage being present in said housing, and wherein said plunger includes a foot portion adapted to pass through said openings and into said passage of said housing and a laterally extending pad portion which presses against said fingers of said contact leaf to effect said displacement thereof as said pad contacts said leaf. 4. Apparatus in accordance with claim 3 wherein said foot is of generally cylindrical shape, said depressed portion thereon comprising a flat on said cylinder, the said tactile ball resting against the shoulder defined between said flat and the remaining portion of said cylinder when said plunger is in an undepressed condition. 5. Apparatus in accordance with claim 3 wherein said plunger support passage includes a keyway extending longitudinally therein and said plunger foot includes a longitudinal slot for engaging said keyway and steadying the lateral movement of said plunger, whereby to reduce wobble at said key top. 6. Apparatus in accordance with claim 1 wherein said housing is formed with a transverse platform for supporting said contact plate, said platform being stepped upwardly at an end thereof to define a narrow support ledge for the base portion of said contact leaf. 7. Apparatus in accordance with claim 1 wherein said housing further includes a plurality of passage ways about the periphery of said platform extending through the body of said housing to the back side thereof, said passage ways being adapted to receive diodes therein with the leads of the diodes being accessible from both sides of said passage ways, and where said contact plate further includes a plurality of openings registrable with the said passage ways in said housing, whereby to readily connect said plate to said diodes. 8. The switch of claim 1 wherein the contact fingers are substantially parallel and extend substantially at right angles to the branch portion in substantially the same plane as the branch portion. 9. The switch of claim 1 wherein the contact leaf comprises a pair of branch portions extending from said base portion and branching into multiple contact fingers. 10. The switch of claim 9 wherein the branch portions and finger portions are located in substantially the same plane. 11. The switch of claim 10 wherein the base portions, the branch portions and the fingers of said leaf surround and define an opening in said leaf. 12. A low profile keyboard switch comprising in combination: a. a switch housing; b. a contact plate mounted in said housing; c. a contact leaf supported in cantilevered fashion in said housing, said leaf being positioned approximately in parallel spaced relationship to saId plate, said leaf comprising a base portion, a branch portion extending from said base portion, and multiple contact fingers connected to said branch portion and cantilevered over said contact plate, the contact fingers of said branch portion being substantially in the plane of the branch portion and extending in a direction significantly different from that of the branch portion so that at least one contact finger is considerably closer to the base portion than at least one other contact finger; d. plunger means adapted to bear upon said leaf and displace the cantilevered portion thereof into contact with said contact plate to close said switch; e. a key top engageable with the top of said plunger means; and f. means for connecting said leaf and plate to an electrical circuit for control by said switch. 13. The switch of claim 12 wherein the contact fingers are substantially parallel to one another and are at substantially right angles to the branch portion. 14. The switch of claim 12 wherein there are two spaced-apart branch portions extending from the base portion of the leaf and the contact fingers of the two branch portions extend toward one another. |
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