Position detection system for hydraulic piston/cylinder device

摘要

The position detection system has an electrical contact between relatively displaced metal parts (2,3) of the piston and cylinder provided by a pair of spring elements (4,5), each received in a respective annular groove in one of the metal parts and providing an angled screw spring function. The annular grooves lie side-by-side, with the spring elements in direct contact with the second metal part, to provide an electrical termination for an electromagnetic wave resonator space provided within the cylinder between the piston and one cylinder end, the piston position determined from the frequency of the resonance peak.