Lubricant metering assembly

Claim 1

A lubricant metering assembly for supplying a substantially constant flow of lubricant to an apparatus to be lubricated which comprises: a housing including a base member, an outer wall element about said base member and an inner wall member extending downwardly from said base member, said base member being provided with a substantially flat top wall and including thread means, said inner wall member having a lubricant supply passageway formed therethrough with an upper portion thereof of reduced cross-sectional area thereby forming a guide means, said top wall of said base member of said housing being provided with an upwardly extending cylindrically shaped section forming a channel with said outer wall to receive a sealing ring; said top wall being provided with a concentric rib within said channel; a cylindrical lubricant container comprised of an end wall and side wall positioned within and mounted to said housing, said container having at least one orifice about said end wall, said end wall being provided with a downwardly extending positioning means, said side wall being provided with thread means and a downwardly extending rib formed on lower terminal portion thereof; a sealing ring compressively disposed in said channel of said base member between said base member and terminal portion of said end wall of said container; a piston including a downwardly extending stem, said piston being provided with peripheral seal means for contacting the interior surface of the side wall of said container and an upwardly extending positioning means, said stem being cylindrically-shaped and in contacting relationship with said guide means with a spacing of less than 0.010 inches, said stem being provided with at least one exterior channel of increasing cross-sectional area as measured upwardly from the lower terminal portion of said stem, said piston being formed with a substantially flat bottom wall which cooperates with said flat top wall of said base member thereby minimizing the amount of lubricant remaining in said assembly upon completion of travel of said piston with the travel distance of said piston being greater than 35 percent of the overall height of the assembly; and a coil spring disposed between and about the positioning means of said container means and said positioning means of said piston, said spring having decreasing compressional force compensated by a passageway of increasing cross-sectional area formed by said channel and said guide means to permit substantially constant flow of lubricant.