The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 28, 1990
Filed:
Dec. 04, 1989
Lael B Taplin, Union Lake, MI (US);
Vickers, Incorporated, Troy, MI (US);
Abstract
An electrohydraulic control system includes an actuator having a cylinder and a piston variably positionable therewithin. An electrohydraulic valve is responsive to valve control signals for coupling the actuator to a source of hydraulic fluid. A coaxial transmission line extends through the actuator, and includes an outer conductor formed by the actuator cylinder and a center conductor operatively coupled to the piston such that length of the coaxial transmission line is effectively directly determined by position of the piston within the cylinder. An rf generator is coupled by an antenna to the coaxial transmission line for launching rf energy therewithin, and valve control electronics is responsive to rf energy reflected by the coaxial transmission line for indicating position of the piston within the cylinder and generating electronic control signals to the valve. The antenna includes a pad positioned radially adjacent to but spaced from the center conductor of the transmission line, an rf connector axially spaced from the pad, and an exponentially tapering transmission line that extends axially and radially from the pad to the connector. The dimensions of the tapering transmission line are tailored to match characteristic impedance of the coaxial transmission line to that of the electronics at the rf connector.