IMPROVED CUTTER HEAD MOUNTING FOR DRILL BIT

摘要

An improved bushing mounting structure for mounting and lubricating a rotatable cutter head on a mining or oil well drilling bit includes a spindle and cutter wheel in which axial forces bear simultaneously on two distinct complementary surfaces that are spaced axially from each other. A split bushing with a compressible silver coating ensures simultaneous loading of the axial bearing race surfaces while also providing natural lubricant to the race surfaces. A slanted seal retainer groove accommodates a larger bushing positioned closer to the bit leg and a larger seal while allowing more and longer wear on the cutter wheel. An interchangeable differential sleeve and piston lubrication system is provided to adopt grease delivery forces to different well depth and drilling fluid weight conditions.