Protective environment for keyboard actuatable switches |
|||||||
| 申请号 | US33737473 | 申请日 | 1973-03-02 | 公开(公告)号 | US3829632A | 公开(公告)日 | 1974-08-13 |
| 申请人 | BURROUGHS CORP; | 发明人 | KLEHM W; | ||||
| 摘要 | Relates generally to the production of electricial signals from a keyboard, each key of which is individually operatively associated with a switching device whose activation to electrical conductive condition is controlled by the displacement of the key. These switches are hermetically sealed from the atmosphere and are electrically scanned in succession at relatively high speeds and at a repetitious rate such that several scanning cycles occur during the normal activation of a selected key. The keyboard mechanism also includes a shift register having one more bit position than the number of switch devices and into which a bit is introduced into the ''''one'''' position at the instant the scan encounters a closed switch of the keyboard. This bit is then shifted through the register in timed relation to the scan of the remaining key switches and unloaded into the last bit position of the register. A detector senses the presence of a bit in both the ''''one'''' position and the last position of the shift register and upon detection of a bit solely in the one position it delivers a signal indicative of the character represented by the actuated key and upon detecting bits in the two extreme positions of the shift register it nullifies the delivery of such a signal. | ||||||
| 权利要求 | 1. A keyboard assembly including, in combination: a base panel member of electrically insulating material carrying on the upper surface thereof a thin pattern of electrically conductive elements; a second panel member of electrically insulating material superposing the base panel member in slightly spaced apart relationship thereto; a first impervious flexible sheet interposed between the two members and encompassing an area approximating the same, the edges of the impervious sheet effectively sealingly engaging the marginal portions of the base panel member to form a sealed chamber therebetween extending to the marginal portions of the base member; a plurality of actuatable keys carried by the second panel member having key stems extending downwardly therethrough and each being capable of reciprocal movement in the direction of its stem, each such key being depressible when actuated and thus to cause the lower end of its associated key stem to enter the space between the members and engage and depress the impervious sheet; a second flexible sheet of electrically insulating material interposed between the first impervious flexible sheet and the pattern of conductive elements on the upper surface of the base panel member and normally separating the first impervious sheet and the base member from one another, the second flexible sheet having perforations in alignment with the pairs of contacts and the key stems; and a plurality of pairs of normally spaced apart electrical contacts in the sealed chamber each pair of which is individually associated with a key of the keyboard and aligns with the key stem thereof, one contact of each pair of contacts forming one of the printed conductive elements of the base member and the other contact of each pair of contacts forming part of the surface of the first flexible sheet confronting the base member, each pair of contacts being brought into engagement with one another in response to the depressive movement of the associated key of the keyboard and the resulting deflection of the immediate area of the first flexible sheet through the aligned perforation of the second flexible sheet. 2. A keyboard assembly in accordance with claim 1 wherein the lower end of each stem of each key of said plurality of actuatable keys terminates in a diaphragm of resilient material forming a hollow body which is partially collapsible when the lower end of the key encounters resistance to its depression, the diaphragm of each key carrying a thicker solid tapered protrusion on the underside thereof which when the key is depressed will force the immediate area of the flexible sheet bearing electrically conductive contacts through the aligned perforation of the electrically insulating sheet and into engagement with the electrically conductive element aligning therewith and carried by the base panel member of the assembly. 3. A keyboard assembly in accordance with claim 2 wherein the upper end of each key stem terminates in a key top and wherein a resilient collapsible boot encircles the upper end of the key stem in engaging relationship to the key top and yieldingly urges the key stem to its raised position with respect to the keyboard assembly. |
||||||
| 说明书全文 | |||||||
QQ群二维码
意见反馈
意见反馈