Method to prevent debris build-up on reciprocating air motor pilot valves
AssigneeGraco Minnesota Inc.
InventorsMark L. Bauck, Zaixing You, Xueshui Wu, Jin Tian
Life of this patent
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Abstract
An end cap assembly for a reciprocating air motor comprises a pilot valve and an end cap body. The pilot has a valve stem. The end cap body comprises a central bore for receiving an air motor rod, a valve bore in which the pilot valve is disposed such that the valve stem extends through the end cap body, and an air port extending through the end cap body. The air port has a contour to direct air toward the valve stem.
Claims18
An end cap assembly for a reciprocating air motor, the end cap assembly comprising:
- a pilot valve having a valve stem;
- an end cap body comprising:
- a central bore for receiving an air motor rod;
- a valve bore in which the pilot valve is disposed such that the valve stem extends through the end cap body;
- and
- an air port extending through the end cap body, the air port having a contour to direct air toward the valve stem;
- and
- a flow deflector coupled to the end cap body to overhang the air port and direct air from the contour toward the valve stem, wherein the flow deflector is disposed in a counterbore in the end cap body so as to be inlaid in the contour.
A reciprocating air motor comprising:
- an air piston;
- a drive rod extending from the piston;
- an air motor housing defining a cylinder wall, the air motor housing comprising:
- first and second end walls located at opposite ends of the cylinder wall;
- a central bore extending through the first end wall and that receives the drive rod;
- first and second air passages extending through the first and second end walls, respectively;
- first and second valve bores extending into the first and second end walls, respectively;
- a reversing valve for alternatively providing compressed air to the first and second air passages;
- and
- first and second pilot valves disposed in the first and second valve bores, respectively;
- and
- a flow deflector coupled to the first end wall;
- wherein the first air passage includes contouring to direct airflow toward the first pilot valve;
- and
- wherein the flow deflector is disposed within a counterbore within the first end wall so as to be inlaid in the contouring to funnel airflow from the contouring to the first pilot valve.
A method of removing contaminants from a valve stem in a reciprocating air motor, the method comprising:
- reciprocating a reversing valve to alternately deliver compressed air to opposite sides of an air motor piston through first and second ports extending through a piston cylinder;
- activating the reversing valve using first and second pilot valves having first and second valve stems, respectively, that engage opposite sides of the air motor piston within the cylinder;
- and
- directing blow-off air from the first port across the first valve stem, comprising:
- passing the blow-off air across a contour that guides air from the first port towards the first valve stem;
- and
- turning the blow-off air from the contour towards the first valve stem with a deflector overhanging the first port and disposed within a counterbore in a surface of the piston cylinder through which the first port extends so as to be inlaid in the contour.
Dependencies are inferred from the claim text.