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:
Sep. 09, 1980
Filed:
Aug. 23, 1978
Wilhelm Zirps, Hemmingen, DE;
Hugo Preun, Asperg, DE;
Robert Bosch GmbH, Stuttgart, DE;
Abstract
The hydraulic lifting device for harvesting machines includes a hydraulic cylinder-piston unit mounted on the wheel frame of the machine and supporting most of the weight of the harvesting apparatus so that the latter abuts against the ground with residual weight only. The cylinder-piston unit is controlled by a multi-way selector valve and a locking valve unit connected in a first working pipeline system. The hydraulic device further includes a pressure limiting valve for setting a reference pressure for the hydraulic cylinder-piston unit, the limiting valve being connected in an additional working pipeline that is branched upstream the limiting valve to a nonreturn valve and therefrom is connected by a direct conduit to a hydraulic accumulator and the hydraulic cylinder-piston unit. The combination of the pressure limiting valve with the non-return valve and the branch conduit prevents during the lowering of the piston-cylinder unit the hydraulic accumulator from being completely discharged, accelerates the lowering movement and improves the seal of the entire lifting device.