Electrical keyboard switch mechanism with improved resilient diaphragm contact actuator |
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| 申请号 | US3584162D | 申请日 | 1970-02-16 | 公开(公告)号 | US3584162A | 公开(公告)日 | 1971-06-08 |
| 申请人 | IBM; | 发明人 | KRAKINOWSKI MORRIS; | ||||
| 摘要 | A keying mechanism is described which can be advantageously employed in a high density or highly miniaturized keyboard. The mechanism employs the principles of an elastic diaphragm switch but, instead of including a continuous elastomeric sheet, such switch comprises a discrete elastomeric plunger for each key operating position, the plungers being freely guided through an apertured guide plate. An elastomeric nomenclature sheet is provided on the guide plate to provide key indicia and to seal the mechanism against dust and dirt. A metallic grid having apertures at the key positions is provided on the nomenclature sheet and functions to prevent accidental triggering of the keyboard. | ||||||
| 权利要求 | 1. A keying mechanism for a high density keyboard comprising: a base assembly having an array of first conductive contact means thereon, each of said contact means being disposed to be in registration with a key position of said keyboard; a substantially incompressible insulating layer overlaying said base assembly, said insulating layer having spaced apertures therethrough which are respectively aligned with said first contact means, a diaphragm assembly overlaying said insulating layer, said diaphragm assembly having an array of second conductive contact means, said diaphragm being disposed whereby respective first and second conductive contact means are in opposed relationship and normally separated by gaps respectively formed by said openings, an apertured guide plate above and spaced from said diaphragm, the apertures in said plate being substantially in registration with the apertures in said insulating layer; a plurality of plungers for respectively being received in the apertures of said guide plate, each of said plungers comprising a larger and wider upper portion which is freely receivable within a guide plate aperture and a second narrower and lower portion extending from the base of said upper portion, said second and lower portion being substantially in registration witH said first and second contact means, at least said lower portion of said plunger comprising an elastomeric material; and an elastomeric nomenclature sheet on the upper surface of said guide plate to seal said mechanism against dust and dirt and adapted to receive force from a stylus thereagainst at a keying position to cause a corresponding plunger to force said first and second contact means at a keying position into electrical contact. 2. A keying mechanism as defined in claim 1 and further including a perforated metallic layer on said nomenclature layer, the perforations in said metallic layer being located at said key positions, said nomenclature layer having different key indicia at each of said key positions which are visible through said perforations in said metallic layer. 3. A keying mechanism as defined in claim 1 wherein the elastomeric material of said plunger is an elastomer filled with a nonshedding lubricant. 4. A keying mechanism as defined in claim 1 wherein there is further provided an apertured retaining sheet to which said guide plate is affixed, the apertures of said retaining sheet being in registration with the apertures of said guide plate and having respective diameters of sufficient magnitude to permit the free passage therethrough of the lower and narrower portions of said plungers. 5. A keying mechanism as defined in claim 1 wherein the thickness of said guide plate is so chosen whereby there is a gap between said plungers and said nomenclature sheet. 6. A keying mechanism as defined in claim 1 wherein the upper and lower portions of said plungers are cylindrical and wherein the diameters of said lower portions are about one-half the diameters of said upper portions, respectively. 7. A keying mechanism as defined in claim 6 wherein the respective combined lengths of said upper and lower portions of said plungers are at least equal to the diameters of said upper portions. 8. A keying mechanism for a keyboard comprising: a base assembly having an array of first conductive contact means thereon, each of said contact means being disposed to be in registration with a key position of said keyboard; a substantially incompressible insulating layer overlaying said base assembly, said insulating layer having spaced apertures therethrough which are respectively aligned with said first contact means, a diaphragm assembly overlaying said insulating layer, said diaphragm assembly having an array of second conductive contact means, said diaphragm being disposed whereby respective first and second conductive contact means are in opposed relationship and normally separated by gaps respectively formed by said openings, an apertured guide plate above and spaced from said diaphragm, the apertures in said plate being substantially in registration with the apertures in said insulating layer; a plurality of plungers for respectively being received in the apertures of said guide plate and disposed in registration with said first and second contact means, at least the lower portion of a plunger comprising an elastomeric material; and an elastomeric nomenclature sheet on the upper surface of said guide plate to seal said mechanism against dust and dirt and adapted to receive force from a stylus thereagainst at a keying position to cause a corresponding plunger to force said first and second contact means at a keying position into electrical contact. 9. A keying mechanism as defined in claim 1 wherein the elastomeric material of said plunger is an elastomer filled with a lubricant. |
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