Industrial truck with at least one hydraulic mast lift cylinder
AssigneeJungheinrich Aktiengesellschaft
InventorsKai Fischer, Johannes Michael Frey
Life of this patent
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Abstract
An industrial truck having at least one hydraulic mast lift cylinder, which is connected to a hydraulic block via a hydraulic arrangement that limits a lowering speed of the mast lift cylinder. The hydraulic arrangement is formed to limit the lowering speed in a load-dependent manner to at least two maximum values. A first maximum value is given for the lowering speed at the nominal load while a second maximum value is given for the lowering speed with a load that is smaller than the nominal load, i.e., wherein the first maximum value is less than the second maximum value.
Claims7
An industrial truck, comprising
- at least one mast lift cylinder configured to lift a load carried on a load mast of the industrial truck;
- and
- a hydraulic arrangement defining multiple flow paths for delivering hydraulic fluid to the at least one mast lift cylinder, wherein the hydraulic arrangement is configured to
- control the at least one mast lift cylinder as a function of the load imposed in the load mast by,
- measuring the load imposed on the load mast, and
- changing the flow paths of the hydraulic fluid such that one of a first action and a second action occur in the flow paths,
- wherein the first action corresponds to a first load value when the first lowering speed is limited to one of the flow paths, and
- wherein the second action corresponds to a second load value when the second lowering speed is limited to other flow paths.
An industrial truck, comprising:
- a lift cylinder for suppling hydraulic fluid under pressure for lowering a load carried on a load mast;
- a hydraulic system defining multiple flow paths for delivering the hydraulic fluid to the lift cylinder to effect a lowering speed of the load mast, the hydraulic system configured to measure the load imposed on the load mast;
- and
- a valve operative to supply pressure to at least one of the flow paths,
- wherein the hydraulic system is configured to control the valve to:
- (i) supply pressure to one of the multiple flow paths to effect a first lowering speed and (ii) supply pressure to another of the multiple flow paths, in parallel, to effect a second lowering speed higher than the first lowering speed,
- wherein the hydraulic system further comprises a pressure balance configured to actuate a changeover valve, the changeover valve configured to change the flow paths such that one of two actions occur in the flow paths,
- wherein a first action corresponds to a first load value when the first lowering speed is limited to one of the flow paths, and
- wherein a second action corresponds to a second load value when the second lowering speed is limited by to other flow paths.
Dependencies are inferred from the claim text.