| 摘要 |
A standard keypad comprises a rigid support plate having a front face and formed with an array of throughgoing apertures, respective push-buttons projecting at the apertures through the plate past the front face thereof, and a continuous flexible membrane overlying the front face and formed in front of each of the push-buttons with a relatively thick projecting portion. Thus the membrane seals the apertures around the buttons while allowing same to be depressed via the projecting portions. The switch associated with the push-buttons urges the push-buttons and the overlying thick portions forward from the front face. A shield assembly has a rigid shield plate formed with an array of throughgoing apertures aligned with and generally identical to those of the support plate and having a rear face confronting the front face of the support plate and an opposite front face. The projecting portions of the membrane project forward through the apertures of the shield plate past the front face thereof. The shield plate is itself secured in front of the membrane with the apertures aligned. Respective rigid caps fitted over the thickened portions project forward through the shield-plate apertures and each have an outwardly projecting flange extending generally parallel to and lying between the plates and of greater size than the respective shield-plate aperture. These flanges normally lie against the rear face of the shield plate.
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