| 摘要 |
<p>A sub-assembly (20) is constructed to form part of a housing for electronic equipment and to he capable of carrying electronic components. The sub-assembly (20) comprises an injection moulded plastics body having an area (21) in which a regular array of apertures (22) are formed, pushbuttons (23) being mounted in each aperture of the regular array of apertures. The pushbuttons (23) are shaped and dimensioned so that they cover the whole of the first area (21), the gaps between the pushbuttons (23) being limited to those required to allow clearance for operation of individual pushbuttons (23). Some of the pushbuttons are replaced by cover plates (24, 25) which are mounted in appropriate apertures of the array of apertures. The pushbuttons (23) operate on dome shape elastomeric switching elements (45) arranged between the pushbutton plungers (43) and the printed circuit hoard (40). The domes have an electrically conductive portion which bridges conductive tracks on the printed circuit board when the corresponding pushbutton is depressed. The subassembly (20) further comprises a second area (31) in which a single aperture (32) is provided which covers a major portion of the second area (31).</p> |
