| 摘要 |
A switch comprising a generally tubular housing (10) of a rigid plastics material. A plurality of discrete tabs (12) are circumferentially disposed, in side-by-side relation, around an end of the housing (10). The housing (10) defines a recess (16) for receiving an elastomeric dome member (24) having a n annular rib (26) at its base, and the recess (16) has an annular groove (20) with a relatively sharp edge (22) for receiving the annular rib (26) of the dome member (24). When the dome member (24) is correctly inserted within the recess (16), a downward force is provided on the tabs (12), causing them to 'fold' down over the base of the dome member (24), such that they are substantially at right-angles to the longitudinal sidewall of the housing (10), and substantially flush with the edge portion (29) thereof. Optionally , heat may also be applied to the tabs (12), causing them to at least partiall y soften and melt together, to form a single, substantially integral, flange completely covering the annular rib (26) at the base of the dome member (24) , so as to create a fluid-tight seal between the housing (10) and the dome member (24). The end of the housing (10) opposite to that having the tabs (1 2) is provided with an aperture (30) with which the stem (32) of a keycap 34 is slidably engaged.The recess (16) for receiving the dome member (24) is shape d and configured so as to provide sufficient clearance such that the dome memb er (24) does not contact the inner wall of the housing (10) when it is deformed in use.
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