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:
Apr. 16, 1991
Filed:
Jul. 02, 1990
James C Goade, Joliet, IL (US);
Claude H Werner, Manhattan, IL (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
Reversible, variable displacement, hydraulic devices are useful in transmitting power from an engine to a driven device. The hydraulic components of such devices are generally quite bulky and difficulty to center to swash plate thereof. The subject device includes a pair of servo valves adjustably disposed within a case for individually controlling the flow of actuating fluid to and from a pair of hydraulic servo actuators. A servo feedback mechanism is provided to mechanically move a valve spool of one of the servo valves to a position for exhausting fluid from one of the servo actuators as the spool of the other servo valve is moved to a position for directing actuating fluid to the other of the servo actuators. The feedback mechanism also moves the spools substantially to their neutral position when a swash plate controlled by the servo actuators reaches a desired angular position after the other spool is first moved to the position for directing actuating fluid to the other servo actuator. The feedback mechanism is compact and cooperates with the adjustability of the servo valves so that centering of the swash plate is simplified.