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:
Nov. 13, 2018
Filed:
Dec. 22, 2011
BO Vigholm, Stora Sundby, SE;
Andreas Ekvall, Hallstahammar, SE;
Kim Heybroek, Eskilstuna, SE;
Volvo Construction Equipment AB, Eskilstuna, SE;
Abstract
A method for controlling lowering of an implement of a working machine is provided. The working machine has a hydraulic system including a hydraulic cylinder for moving the implement and a first control valve for controlling the flow of hydraulic fluid from the piston side of the hydraulic cylinder, and a recovery unit connected to the control valve for recovering energy by receiving a return flow from the piston side of the hydraulic cylinder. The piston side of the hydraulic cylinder and the control valve are connected to each other, and the piston rod side of the hydraulic cylinder is connected to the control valve and to the recovery unit in a point between the control valve and the recovery unit. The method includes identifying a requested lowering speed of the implement, and identifying a desired pressure at the piston side of the hydraulic cylinder and controlling the recovery unit to provide a counter pressure resulting in the desired pressure at the piston side of the hydraulic cylinder, and enabling fluid communication between the piston side of the hydraulic cylinder and the recovery unit, and between the piston side of the hydraulic cylinder and the piston rod side of the hydraulic cylinder, via the control valve, and controlling the control valve in such a way that the flow through the control valve corresponds to the requested lowering speed of the implement.