Rubber-made covering member for push button switches

摘要

The invention provides a push button switch covering member integrally made of a rubbery elastomeric material having an improved structure with which a much larger key stroke is obtained before a snapping action takes place in the covering member when the member is pushed at the center portion leading to the contact of the contact points than in the conventional ones. The covering member is constructed of (a) a central pushing part, (b) a first annular portion which may be in a form of a truncated cone or a cup laid upside down and is connected to the central pushing part at the upper end, (c) a second annular portion encircling and connected to the first annular portion and (d) a base flat connected to the second annular portion, at which the covering member is mounted on the base board of the switch, the relationship between the strengths of the first and the second annular portions being such that the first annular portion does not undergo a buckling deformation before the second annular portion is substantially deformed or bent around the connecting line between the second annular portion and the base flat.