Abstract: In a resin-embedded switching element provided with a casting containment, which encloses an area of the switching element to be covered by a resin, the casting containment has a fill hole consisting of a blind bore having at its inner end a diaphragm which is sufficiently thin that it can be ruptured by casting resin supplied to the fill hole under pressure and a measuring opening is formed in the top of the casting containment through which air can escape during filling of the casting containment with liquid casting resin and the level of the casting resin in the casting containment can be controlled.

Abstract: In a splash-water protected keyboard having a contact foil arranged in a housing and a rubber mat with switch domes disposed over the contact foil and keys with contact stems disposed in the housing over the switch domes for actuating the contacts in the contact foil, the rubber mat has upwardly extending circumferential projections such that the rubber mat forms a trough structure which is provided at least at one edge with discharge spouts extending into openings in the housing bottom plate for discharging any liquid collected in the trough structure.

Abstract: In a push button switch with a star wheel having segments with trip cams and being supported in the push button so as to be rotatable about an axis which is normal to the operating direction of the push button, the star wheel is rotated, when the push button is actuated, by an unlatching structure formed on a rotation latch disposed adjacent the star wheel and engaging a projection on the star wheel. The trip cam wheel has cams which operate contact springs disposed adjacent the star wheel along the path of actuating movement of the star wheel whereby contacts are closed or opened depending on the angular position of the cams. Upon release of the push button, the push button is returned by return elements to its original position while the star wheel slides along the contact springs without operating the contacts.

Abstract: In an ergonomic keyboard comprising at least two housing sections with separate key pads wherein the two housing sections are interconnected by a joint permitting pivoting and also tilting of the two housing sections relative to each other, the joint comprises a coil spring which extends between, and is connected to, the two housing sections at the end of the housing sections remote from an operator so as to form a universal joint between the two housing sections, and a sector-shaped indexing plate is mounted with one end firmly to one of the housing sections and extends into the other housing section so that it bridges any gap formed between the two housing sections when they are pivoted apart, and the other housing section has a guide pin projecting into a partial circular guide slot formed in the indexing plate and having a center of curvature coinciding with the universal joint pivoting center for guiding the two housing sections relative to each other.

Abstract: In a keyboard housing a housing top with a key pad and a housing bottom with support legs wherein the housing includes a support mat and a multi-layer contact foil set arranged underneath the key pad to be actuated thereby, a metal plate is embedded in a recess formed in the housing bottom below the contact foil set so as to increase weight and rigidity of the housing without the need for special molded housing reinforcement structures, the housing bottom, however, having U-shaped reinforcement web structures with bearing studs at their base areas near the housing bottom and housing legs with bearing holes receiving the bearing studs so as to be pivotally supported thereby, the housing legs having locking grooves and the housing bottom having, between the web structures, engagement tongues with locking ribs for engagement with the locking grooves in the housing legs.

Abstract: A key switch which is particularly suitable for low profile keyboards includes a plunger whose contacting movement is converted by means of trigger cams into a movement perpendicularly to the plunger movement for switching a contactor which is movable relative to a stationary contact element, the contactor being formed as annular sheet metal part which is elongate in a direction normal to the switching movement and due to its length can accommodate relatively high stress without material fatigue.

Abstract: A multiple-key unit is provided that includes a top portion, a base portion and a support mechanism. The support mechanism is provided with a body portion and a substantially U-shaped wire. The U-shaped wire includes a cross-part and two free ends that are inwardly bent and are parallel to the cross-part of the wire. The cross-part of the U-shaped wire is rotatably supported in a bearing in an eccentric manner at the key top and is parallel to the central, longitudinal axis of the key top. An assembly stop extends from the bearing and maintains the U-shaped wire, during assembly, in an oblique assembly position. Moreover, wire guides are provided in the cross-sides of the key base to vertically receive the free ends of the U-shaped wire during assembly, and in which wire guides the free ends are horizontally displaceable when the key is actuated.

Abstract: A key module for a membrane switch keyboard has a flat spring running diagonally to the key housing on the bottom side which, with the aid of a plunger, is bent for the operation of membrane contacts. The flat spring with one free end is inserted into a slot which is open toward the top and permits an adjustment of the flat spring by pressure loading on the free end or on the bottom side against the lower section of the flat spring, which is adjacent to the bent free end. The free end of the flat spring is rigidly retained in a slot at the key housing. For the adjustment of the operating force a compression spring is arranged inside the plunger and is supported against a cross-piece running over the flat spring.