Abstract: For use in medical trays the filtering flat material (2) has to be such that no micro-organisms can penetrate through it. In order to arrange such a filter (1) for achieving closure of a tray's partial surface including through openings which ensures sterility, a closed sealing line, which surrounds the through openings, is formed in the area of each flat partial surface having through openings, along which two tray parts to be assembled and including co-operating clamping surfaces enable clamping the seal (3) of the filter (1). By the elasticity of the seal (3) sufficiently good closure is ensured even by small clamping pressure and even with not precisely plane clamping surfaces. The bond of the seal (3) to the filtering flat material (2) has the additional advantage that the filter (1) can also be arranged at a lower surface by pressing its seal (3) into a corresponding groove and does not loosen due to gravity.

Abstract: Two similar switch apparatuses are mounted in switching direction at equidirectional closing direction onto a base. Each apparatus has an extension which is movable together with the armature of the corresponding apparatus and which extends in a respective L-coulisse of a two-armed lever placed on a stub shaft of a casing of one of the switch apparatuses to pivot thereabout. If one of the switch apparatuses carries out its switch closing operation, its extension moves in a path section of the coulisse at an acute angle relative to the direction of radius, causing a counterclockwise pivoting movement of the lever. Conclusively, the extension of the other switch apparatus will be caused to be located into a path section of its coulisse extending circularly around the stub such that the latter extension is blocked, preventing a switching movement.

Abstract: The auxiliary contact assembly comprises a two part casing having an upper section for receipt of the fixed contacts provided with the connecting screws and a lower section having the shape of a trough open on top and mounted to the upper section by means of locking detents. The fixed contacts are clamped into recesses located in the upper section and open at their sides. A at the bottom open channel is formed at the upper section and acts as guide for the contact bridge carrier. The side walls of the trough-shaped lower section enclose the fixed contacts in the recesses and are provided with narrow projections extending upwards into the area of the connecting screws and form thereby a protection against accidental contact. The contact bridge carrier which is provided with a plurality of contact bridges is guided at the bottom by the lower section of the casing. The lower section is provided with mounting elements and a through hole for the coupling member of the contact bridge carrier.

Abstract: The coupling system is assembled upon the placing of the auxiliary contact block including its dogs integrally formed at its bearing surface and its coupling member including a coulisse onto the switch apparatus followed by a shifting of the auxiliary contact block. When placing the auxiliary contact block onto the switch apparatus the dogs engage between tooth-shaped projections in the trough built on the switch apparatus. During the shifting carried out thereafter, the dogs are shifted under the projections and moved into engagement. A catch is located in the trough, which catch is integrally formed on the movable contact carrier of the switch apparatus and which catch upon shifting of the auxiliary contact block is moved in the coulisse of the coupling member formed on the auxiliary contact carrier. This form locked and releasable coupling is safeguarded against a shifting by means of locking members.