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. 08, 1989
Filed:
Aug. 24, 1987
Larry J Oliphant, Swisher, IA (US);
Harnischfeger Corporation, Brookfield, WI (US);
Abstract
A compact retrieval winch and a control therefor are mounted on a recovery vehicle for pulling an immobilized heavy vehicle, such as a military tank, back onto suitable terrain. The winch comprises a support structure, a rotatable hollow cable drum with a cable wrapped thereon, a reversible variable displacement hydraulic motor for driving the drum through a multi-stage power transmission mechanism located within the drum, and a drum brake. The winch control comprises a sensing mechanism for sensing the number of layers of winch cable wrapped on the drum while the drum is operating in the pulling mode and the cable is connected to the tank. The winch control further comprises a hydraulic control circuit, including a constant line pull valve assembly responsive to movement of the sensing mechanism, for controlling the displacement of the hydraulic motor so as to maintain constant maximum cable pulling force regardless of the number of layers of cable on the cable drum.