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US 2002/0153514 A1Published application
Simplified hydraulic circuit for a quick-rise hydraulic lifting jack
AssigneeMcNeil (Ohio) Corporation
InventorMatthew A. Wixey
Life of this patent
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Abstract
A hydraulic fluid circuit for a quick rise type lifting jack positions multiple valves that control two stages of the lifting operation of the jack in the same valve housing machined into a base of the jack and thereby reduces the costs involved in manufacturing and assembling the hydraulic circuit of the jack.
Claims20
A lifting jack having a hydraulic circuit comprising:
- a pump;
- a lifting cylinder;
- a lifting piston mounted in the lifting cylinder for reciprocating movement therein;
- a plurality of fluid conduits communicating the pump with the lifting cylinder;
- a valve housing interposed in the plurality of fluid conduits between the pump and the lifting cylinder, the valve housing having a first cavity containing a first spring biased valve element and a second cavity containing a second spring biased valve element, and the first and second cavities are extensions of each other.
2 more elements
A lifting jack having a hydraulic circuit comprising:
- a pump;
- a lifting cylinder;
- a lifting piston mounted in the lifting cylinder for reciprocating movement therein;
- a plurality of fluid conduits communicating the pump with the lifting cylinder;
- a first valve element and a second valve element interposed in the plurality of fluid conduits between the pump and the lifting cylinder;
- and
- a spring between the first and second valve elements biasing the first and second valve elements away from each other.
4 more elements
Dependencies are inferred from the claim text.