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:
Jun. 25, 1991
Filed:
Aug. 31, 1989
Jeffery A Crosser, Joliet, IL (US);
Randall L Mooberry, East Peoria, IL (US);
James D Rinaldo, Joliet, IL (US);
Jose M Salazar-Vior, Washington, IL (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
Cushioned swing circuits sometimes have a restricted passage between the motor conduits to allow the implement controlled by the swing circuit to coast to a stop. However, opening and closing of the restricted passage was manually controlled, thereby requiring an additional manipulative step by the operator. The present cushioned swing circuit includes a cushion valve moveable to an open position to establish communication through vent line means when a pressure differential greater than a predetermined level is generated in one of the motor conduits connecting a directional control valve to a hydraulic motor. The cushion valve is retained in the open position for a predetermined limited time after the pressure differential drops below the predetermined level so that the inertia generated pressure in the circuit is dissipated through the vent line means. At the end of the predetermined limited time, the cushion valve is moved to the closed position blocking communication through the vent line means whereupon the circuit is hydraulically locked. The cushion valve is moved between the opened and closed positions automatically and requires no additional effort by the operator.