Abstract: A resilient intermediate section (12) is arranged inside the hollow cavity (11) of a resilient section (14) of essentially triangular cross-section. The intermediate section (12) has a flat base portion (15) which contacts the base surface (13) of the resilient section (14) and a switching strip (18) is arranged on the flat base portion (15). In addition the intermediate section (12) has limbs (16) which extend into the tapering hollow cavity (11) and encloses the sides of the switching strip (18). If the section (14) bends due to contact with an obstacle then the limbs (16) are respectively acted on by further arching of the side surfaces (17) and act in turn via inwardly directed actuating ribs (20) on the surface of the switching strip (18) which faces the apex edge (19) of the resilient section.

Abstract: In a light barrier apparatus for monitoring doorways to the left and to the right of a central post two light transmitter/receiver devices (11, 12) are mounted together with the associated electronic circuitry on a structural element to form a first unit. This unit is releasably secured to a base member which carries two deflecting mirrors (14, 15) and the electrical connection terminals. The unit can be removed from the base member (17) at right angles to a plane which includes the optical axes (11c, 12c) of the light transmitter/receiver devices (11, 12).

Abstract: An elongate resilient section at the closure edge of a closure movable to close an opening contains at least one electrical switching strip 11 which is arranged in an associated hollow cavity (13, 14; 113) close to the elongate securing block (28; 120) used to secure the resilient section to the closure edge. The resilient section is so constructed that the electrical switching strip or strips (11; 11, 12) is actuated not only by compressive forces acting in the direction of closure but also by forces acting sideways on the resilient section.