| 摘要 |
<p>A keyboard switch (40) includes a portion of a sheet (21) of moulded silicone rubber having raised sides (22, 22 min ) supporting a key button (23). A projection (41) on one of the raised sides (22 min ) bears on membrane switch electrical contacts (42) when the key button (23) is depressed. One raised side (22) has a geater length and thickness than the other side (22 min ) and includes a ridge (27) at the base so as to provide a cantilever action pivoted at the ridge when the switch is operated. The cantilevered side (22 min ) provides a positive locating movement and the more resilient side (22) provides a "snap" action to the switch. In another embodiment (not shown) the electrical contacts are positioned above a surface having a recess with a central pip in the recess; when the key button is depressed, the electrical contacts are compressed between the pip and the bearing portions of the key button (or associated projection).</p> |
