Diffusion ring for limiting hydraulic ram travel

Claim 2

In a hydraulic device, means providing first and second liquid chambers and a wall separating said chambers, said wall having a liquid flow passage connecting said chambers, a slidable member in the first of said chambers having a portion engaging the surface of the wall and movable across said passage during usage of the device, and a high porosity diffusion member set into said wall to form a part of the surface thereof in said first chamber and slidably engaged by said slidable member portion, said diffusion member covering said passage so that liquid flowing through the passage flows through the diffusion member.

Claim 3

A device as set forth in claim 1 wherein the area of the diffusion member which forms a part of the wall surface is materially greater than the cross sectional area of said flow passage.

Claim 4

In a hydraulic ram device, a reservoir, means providing a ram chamber having a wall, a ram in the ram chamber having a pressure end sliding on said wall, means providing a stroke limiting drain passage having an outlet in the reservoir and an inlet in the ram chamber, said inlet being located adjacent the position occupied by the pressure end oF the ram when the ram has moved to substantially the desired termination point for ram travel, and a low density, high porosity diffusion member forming the inlet for said drain passage and also forming a portion of the surface of the ram chamber wall engaged by said sliding pressure end, said diffusion member being materially greater in area than the cross-sectional area of said drain passage, said ram chamber wall having a recess, said member being seated in said recess.

Claim 5

In a hydraulic ram device, a reservoir, means providing a ram chamber having a wall, a ram in the ram chamber having a pressure end sliding on said wall, means providing a stroke limiting drain passage having an outlet in the reservoir and an inlet in the ram chamber, said inlet being located adjacent the position occupied by the pressure end oF the ram when the ram has moved to substantially the desired termination point for ram travel, and a low density, high porosity diffusion member forming the inlet for said drain passage and also forming a portion of the surface of the ram chamber wall engaged by said sliding pressure end, said diffusion member being materially greater in area than the cross-sectional area of said drain passage, said ram chamber wall having a recess, said member being seated in said recess.

Claim 6

A device as set forth in claim 3 including gland means for the ram and wherein said recess opens out of one end of the wall, said gland means pressing on said member to hold it in said recess.

Claim 7

40 device as set forth in claim 4 wherein said diffusion member and recess are annular and the member is formed of sintered metal having an average pore size of about 40 microns or less and said ram pressure end has a flexible, nonmetallic packing slidable over the diffusion member.