Abstract: The rotation of a rotary switch is limited by stop ribs in a knob that facilitates the rotation of the rotary switch. The stop ribs can be configured to limit the rotational stress that is applied to the rotary switch, or to limit the states of the switch that are realizable by a particular knob. Using keyed detachable knobs, different keys can be configured to provide different ranges of rotation of the rotary switch, thereby enabling different switching authorizations, based on the particular knob that is used.

Abstract: The electrical switching device (1) has a housing (3) which can be fastened on a support (2), an actuator (8) having a pressing surface and illuminating means for visualization of the pressing surface. A disc-like cover plate (6) which has a contact surface (6b) for a piezoelectric switching element (12) provided in the housing is arranged on the front of the housing (3). Said switching element is arranged in such a way that an electrical signal is generated on pressing the actuator (8) in contact with the cover plate (6). According to the invention, the cover plate (6) is at least partly transparent and is provided, on its underside, facing the interior of the housing (3), with several light emitting diodes (16) distributed regularly over a circle and intended for radiating light out of the cover plate (6).

Abstract: Rotary switches, for example key switches, are switched on and off by the rotational movement of a rotary handle. They are intended for mounting on a front plate and are formed in at least two parts. They furthermore have a rotatable switching means and a rotary knob having a key which can be inserted into the switching means. However, the known key switches have no securing means for preventing overturning of the key. In extreme cases—especially with application of excessive force—this leads to the key bit breaking off, which then generally results in tedious and expensive changing of the entire switch. According to the invention, undesired overturning of the key is prevented by ribs which are arranged on the rotary knob and on the front plate or on the switch housing and can come into contact with one another.

Abstract: The control element according to the invention which for example can be in the form of a pushbutton switch or display element, is intended to be fastened to a front panel having at least one circular opening. It has a housing with an essentially cylindrical section and, at its front, a collar projecting radially outward and beyond the cylindrical section. The cylindrical section is provided with at least one all-around groove in which a ring of an elastically deformable material is present. When the control element is inserted into the front panel, it is fixed into the opening by virtue of the fact that a support surface of the collar rests on the front plate on the one hand and by the ring being pressed against the lateral surface of the groove by the lower edge of the opening on the other hand.