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:
Oct. 26, 1976
Filed:
Aug. 12, 1974
Eugene E Latimer, Wilmington, IL (US);
Caterpillar Tractor Co., Peoria, IL (US);
Abstract
A hydraulic control system having a load-lifting hydraulic motor, a source of pressurized fluid and a pilot-operated directional control valve for directing fluid for operation of the motor is provided with a combined restrictor and shuttle valve assembly that is operative to direct fluid from a pump for pilot-operation of the main control valve when the pump is in operation, but is operative upon failure of the pump system to provide pressure from the load-lifting side of the lifting motors to a pilot control valve for pilot operation of the directional control valve. This assembly provides an emergency source of hydraulic pilot fluid for pilot operation of the main control valve for lowering the implements or load supported by the hydraulic motors should the engine of the vehicle fail.