Key pad with double sandwich construction - has top layer shouldered support press buttons operating foam support contact gap structure

摘要

Pressbutton sections (D) are marked on the top layer (1) insulating cover of the key pad switch which has a rigid insulating material support (2) under it. The support material (2) has a shouldered cut-out at each press button position (D) to accommodate a rigid insulating material (3) shouldered piece on the top layer underside. The insulator (3) can be pressed down (D) until the shoulders meet (4,10) on the press button insulator (3) and rigid underlayer support material (2). The switch contact layer of the sandwich comprises an insulating layer (5) under the rigid insulator sections (2,3) with a contact material (6) at the press button positions (D) on its underside. These are above the base material (8) contacts (7) with which they make. A foam separator insulating material (9) maintains the spacing between contacts (6,7) in the 'off' position and collapses at the edges when a press button is operated. The feature is the shouldered stop (4,10) incorporated in the top sandwich.