Rotary rock bit with improved thrust flange

Claim 1

An improved earth boring bit having a bit body defining a downwardly extending arm with a downwardly, inwardly extending bearing pin, a rolling cone cutter rotatably mounted on said arm, said arm and cone defining cooperating engaging surfaces extending radially with respect to the axis of said pin providing facing engaging thrust bearing areas for the thrust forces between said bit body and said cone, and lubricant disposed between said surfaces to reduce the friction and wear as said cone rotates thereon, and wherein said cooperating radially extending surfaces define a first annular surface on said cone and a mating second annular surface on said pin, said first surface terminating inwardly at an inner shoulder extending away from said arm and outwardly at a second shoulder extending above said first surface toward said arm, said improvement comprising: a plurality of slots in said first annular surface, said slots open to said inner shoulder and terminating closely adjacent said second shoulder and extending from said inner shoulder to said termination point generally in the direction of rotation of said cone, whereby lubricant migrating outwardly from between said facing thrust bearing surfaces is continuously scraped into said slots and forced back toward the inner shoulder of the annular bearing area for replenishing lubricant to the radially inner area of said thrust bearing area.