Hydraulic cab tilt actuator with lost motion
AssigneeActuant Corporation
InventorsBorivoj Krobot, Leonard D. Yoder
Life of this patent
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Abstract
A lost motion piston assembly comprising a lost motion cavity formed within a piston and a lost motion piston disposed within the lost motion cavity. The lost motion piston forms a sealed gas cavity. The sealed gas cavity contracts when the actuator is extended under pressure into the cylinder space and expands under pressure when the actuator is retracted by relieving pressure in the cylinder space.
Claims12
An actuator for tilting a cab of a vehicle between a driving position and a maintenance position, the actuator comprising:
- a cylinder housing having an internal cavity, a rod end and a bore end;
- a piston rod disposed partially within the internal cavity, wherein:
- the piston rod is configured to move axially in a reciprocating manner relative to the cylinder housing;
- the piston rod has an exposed portion extending from the rod end of the cylinder housing which varies in length as the piston rod extends or retracts relative to the cylinder housing;
- and
- the piston rod has an enclosed portion within the cylinder housing which varies in length as the piston rod extends or retracts relative to the cylinder housing;
- a pressure cavity formed between an inner surface of the cylinder housing and the piston rod, wherein:
- the piston rod is forced to extend from the cylinder housing when hydraulic fluid is supplied to the pressure cavity;
- and
- the piston rod is allowed to retract under an external force exerted axially on the exposed portion of the piston rod when the hydraulic fluid is allowed to flow from the pressure cavity;
- a lost motion bore formed in the enclosed portion of the piston rod;
- a lost motion piston disposed within the lost motion bore, wherein:
- the lost motion piston divides the lost motion bore into an isolated gas cavity and a fluid cavity;
- the fluid cavity is in fluid communication with the pressure cavity;
- and
- a gas is disposed in the isolated gas cavity;
- a pressure port disposed on the cylinder housing, wherein:
- the pressure port is in fluid communication with the pressure cavity;
- and
- the pressure port is configured to be connected alternately to a source of hydraulic fluid under a higher pressure or a receptacle of hydraulic fluid under a lower pressure.
A hydraulic tilting device for tilting a cab of a vehicle between a driving position and a tilted position, which cab in the driving position is resiliently supported by a suspension on a chassis of the vehicle, comprising:
- an actuator having:
- a cylinder housing having a cylinder space;
- and
- a piston rod, wherein:
- a first portion of the piston rod is disposed within the cylinder space;
- and
- a second portion of the piston rod extends out from the cylinder space;
- wherein:
- a gas pressure cavity is provided in the cylinder space;
- and
- the gas pressure cavity contracts when the actuator is extended under pressure into the cylinder space and expands when the actuator is refracted by relieving pressure in the cylinder space so as to provide for oscillating extensions and retractions of the piston rod relative to the cylinder housing in the driving position so as not to interfere with the operation of the suspension as the cab bounces up and down relative to the chassis when driving the vehicle.
A lost motion piston assembly for an actuator for tilting a cab of a vehicle between a driving position and a tilted position, which cab in the driving position is resiliently supported on a chassis of the vehicle, comprising:
- a lost motion cavity formed within a piston;
- and
- a lost motion piston disposed within the lost motion cavity, wherein:
- the lost motion piston forms a sealed gas cavity;
- and
- the sealed gas cavity contracts when the actuator is extended under pressure into the cylinder space and expands under pressure when the actuator is retracted by relieving pressure in the cylinder space.
Dependencies are inferred from the claim text.