Patent ID: 6722260
Filing Date: 2004-04-20
Classification: F15B,G01D

Abstract:
An apparatus for measuring relative position of a hydraulic piston in a cylinder, comprising:an antenna rod extending in a direction of movement of the piston fixedly coupled to the cylinder, the rod configured to carry a microwave pulse between a coupling and a distal end of the rod; a sliding member slidably coupled to the piston, the sliding member configured to cause a partial reflection of the microwave pulse; microwave transceiver circuitry coupled to the rod configured to generate and receive microwave pulses; computation circuitry configured to calculate piston position as a function of reflected microwave pulses from the sliding member and the distal rod end; and an insulating receptacle mounted at one end of the cylinder configured to receive the antenna rod and physically couple the rod to the cylinder through an electrical insulator.