Wheel bearing pressure lubricator

Claim 1

A wheel bearing pressure lubricator comprising: (a) a hollow cap having a side wall, a central aperture, an open end and a closed end, said open end being adapted for sealing engagement with a wheel hub, said side wall having an interior surface with a substantially cylindrical shape; (b) a tubular member having connection with a central portion of said closed end and extending therefrom between and concentrically with said side wall; (c) a lubricator fitting connected with said closed end and communicating with said tubular member; (d) a piston structure slidably and sealingly mounted on said tubular member and having a marginal edge thereof sealingly engaging the interior surface of said side wall; said marginal edge having a defined length; (e) a spring member positioned between said piston structure and said closed end and urging said piston structure toward the open end; (f) a vent aperture disposed through said cap at a point adjacent to said closed end; (g) an abutment means in said cap limiting translation movement of said piston structure toward said open end and having openings for communication of wheel hub lubricant pressure to said piston structure; (h) an overflow opening extending through said side wall in spaced relation to said abutment means and at a point whereby the pressure of lubricant in said wheel hub moves said piston structure away from the abutment means to a filled position exposing said overflow opening to prevent excess lubricant pressure in the wheel hub; (i) a piston position indicator aperture in said side wall with a location and size relative to the length of the piston marginal edge to be closed thereby when the piston structure is translated to said hub filled position and to be open when the piston structure engages the abutment means and ceases to apply pressure to lubricant in the wheel hub.