Patent ID: 11905153
Assignee: JUNGHEINRICH AKTIENGESELLSCHAFT
Field: Handling (Mechanical engineering)
Classification: CPC B  F | IPC B

Claim 8:
9. A method of operating a hydraulic system of an industrial truck that includes a lift mast having at least one mast lift stage driven by at least one mast lift cylinder, a free lift stage having a load receiving means driven by at least one free lift cylinder such that the load receiving means is displaceable along the lift mast, the hydraulic system supplying a hydraulic fluid to and unloading the hydraulic fluid from the at least one mast lift cylinder and the at least one free lift cylinder, and a control for the hydraulic system programmed to operate the hydraulic system, the method comprising simultaneously actuating the at least one mast lift cylinder and the at least one free lift cylinder via the control for the hydraulic system such that, in a load lowering operation, the mast lift stage and the free lift stage
(i) simultaneously start retracting, and
(ii) continue to simultaneously retract until one of the mast lift stage and the free lift stage is completely retracted.