Abstract: A contact element is provided, of the type having a domed middle portion that can be manually deflected against a terminal to close an electrical circuit, which avoids damage to the circuit and which can be easily held in place. The contact element has a domed middle portion with a convex front face, a peripheral portion, and a bend between the middle and peripheral portions. The contact element is laid against a printed circuit board, with the bend contacting a first terminal on the board and the middle portion being deflectable to contact a second terminal on the board. An insulative actuator has a button portion that can be pressed against the middle of the contact element, an outer capture portion which captures the outer edge of the contact element, and a hinge connecting the button and capture portions. The outer edge of the contact element lies away from the circuit board so burrs thereon cannot damage the circuit board, and so that the periphery of the contact element can be easily captured.

Abstract: A membrane switch sheet is disposed on a base plate and an adhesive layer is formed all over the membrane switch sheet. A positioning sheet, which has positioning holes respectively corresponding to membrane switches arranged on the membrane switch sheet, is disposed on the adhesive layer, and a tact plate having a normally upward curved portion is bonded to the adhesive layer in each positioning hole. A mounting plate is disposed on the positioning sheet at a distance therefrom. The mounting plate has a sleeve at a position corresponding to each tact plate. A stem is slidably received in the sleeve. The stem is capped with a key top formed integrally therewith. An acutating coiled spring is fixed at one end and engaged at the other end with the tact plate. When the key top is depressed, the coiled spring presses down the corresponding membrane switch through the tact plate, turning on the switch.

Abstract: A rubber spring is disposed on a base on which are mounted fixed electrodes. The rubber spring includes first and second cup sections. The first cup section is in the form of an inverted cup, whose top portion is smaller in diameter than the bottom portion thereof, and is adapted to be bent by a force applied thereto from above and to produce a resilient restoring force corresponding to the size of such deflection. The second cup section, which is located inside the first cup section, has a U-shaped longitudinal section and is adapted to be bent by a force applied thereto from above and to produce a resilient restoring force corresponding to such deflection. Thin-walled portions are formed at the bent portions of the first and second cup sections. A center projection protrudes upward from the center of the second cup section. The top face of the center projection is situated below the upper surface of the support seat.

Abstract: A low profile switch or keypad has one or more touch buttons of circular or polygonal shape in plan formed integrally with and raised from a surrounding membrane of elastomeric material by a wall of resiliently deformable material of thickness and angle relative to the membrane so that the wall can flex under finger pressure on the or each button without deflecting the surrounding membrane. The membrane and at least the periphery of the button are relatively thick and the wall is relatively thin so that deformation during the keystroke is localized in the wall. The length of the wall is about equal to the keystroke and is relatively small compared to the width of the touch button. The junction between the wall and the membrane is located a distance greater than the keystroke above the lower surfaces of the membrane so that the wall passes overcenter during the keystroke resulting in a change in tactile sensation.