Cushioning means for hydraulic cylinder
AssigneeParker-Hannifin Corporation
InventorsBeldon Lee Rich, Zdenek J. Lansky
Life of this patent
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Abstract
Cushioning means for cushioning the end portion of the stroke of a piston in a cylinder comprising a stepped cushioning member or spear which enters a cylinder head bore to form therewith an annular orifice which successively decreases in area and gradually increases in radial width from one step to the next thus to decrease piston velocity at substantially uniform rate and, hence, at substantially constant deceleration with substantially constant pressure drop across the annular orifice.
Claims3
Cushioning means for cushioning the terminal portion of the stroke of a piston in a hydraulic cylinder wherein said cylinder has a bore in one end through which fluid is displaced from said cylinder during movement of the piston therein;
- said cushioning means comprising a member on said piston extending axially therefrom to enter said bore to throttle the flow of fluid through said bore during the terminal portion of said stroke;
- said member having first and second coaxial steps which define with said bore successive first and second annular orifices of stepwise progressively decreasing cross-section area as said piston moves in the terminal portion of said stroke;
- said steps being tapered to smaller diameter toward said piston to provide a sudden radial enlargement as said second step enters said bore and to provide for gradual radial contraction as said first and second steps enter said bore.
Cushioning means for cushioning the terminal portion of the stroke of a piston in a hydraulic cylinder wherein said cylinder has a bore in one end through which fluid is displaced from said cylinder during movement of the piston therein;
- said cushioning means comprising a member on said piston extending axially therefrom to enter said bore to throttle the flow of fluid through said bore during the terminal portion of said stroke;
- said member having a series of first, second, and third coxial steps which define with said bore successive first, second, and third annular orifices of stepwise progressively decreasing cross-section area as said piston moves in the terminal portion of said stroke;
- said steps being tapered to provide sudden radial enlargements as said second and third steps enter said bore and to provide for gradual radial contraction as said first, second, and third steps enter said bore;
- said steps being of crest diameter and of axial length and taper to effect a substantially constant pressure drop across the respective annular orifices thus to decrease the piston velocity at substantially uniform rate and constant deceleration.
Dependencies are inferred from the claim text.