Pressure piston switch with cased pressure member - has stepped piston for pressure member loading, with seals separating pressure surfaces

摘要

The switch is designed for monitoring fluid systems in cranes, hoists etc. It has a pressure member (5), comprising a plunger effectively cooperating with an electric switch, when the pressure member is engaged by a load. A stepped piston (13) is provided for loading the resilient pressure member. Its effective piston surfaces (14,15) are separated by seals (18). Each piston surface is coupled with a supply duct (2,3). The surfaces are preferably of the same size. The piston may be coaxial to the plunger axis (A) and is typically formed by two sections (13a,13b) of different diameters (d1,d2). The larger diameter section (13a) is guided in a housing (1) bore (16) of identical diameter, into which opens a pressure medium duct (3). Similar duct (2) opens into a bore (21) for the smaller diameter section (13b).