Patent ID: 6053264
Filing Date: 2000-04-25
Classification: E21B

Abstract:
Cutter wheel and mounting apparatus for mounting a cutter wheel rotatably on a rock bit leg, comprising:a spindle protruding axially from an inner surface of said rock bit leg, said spindle having a proximal end adjacent said inner surface of said leg, a distal end at a distance away from said inner surface of the leg, a cylindrical midsection between said proximal end and said distal end, an enlarged cylindrical shoulder between said midsection and said proximal end, an enlarged annular flange between said midsection and said distal end, a stub shaft extending axially from said flange to said distal end, an annular end surface extending radially outward from said stub shaft to said flange, wherein said cylindrical midsection, enlarged shoulder, and enlarged flange form an annular race channel between said enlarged cylindrical shoulder and said flange;a cylindrical bushing with an outside diameter and an inside diameter positioned in said race channel in such a manner that said bushing is rotatable in said race channel in relation to said spindle; andsaid cutter wheel having an outer end surface and a cavity extending inwardly from said outer end surface to an inner end surface, said cavity forming a cylindrical inside surface between said outer end surface and said inner end surface, said cylindrical inside surface of said cavity having a midsection diameter that is the same as the outside diameter of the cylindrical bushing and an outer end section diameter that is large enough to allow the cutter wheel to slip over said enlarged shoulder of said spindle with an annular groove in said inside surface juxtaposed to said enlarged shoulder, said annular groove having a polyhedron-shaped cross section with opposed sidewalls that extend radially outward from said inside surface and that slant away from said outer surface, and further including an annular seal member positioned in said annular groove and in encircling, contacting relation with said enlarged shoulder, said cutter wheel being positioned in concentric relation to said spindle with said spindle and said cylindrical bushing being positioned concentrically in said cavity, said outer end surface being positioned radially outward from said shoulder in juxtaposition to said inner surface of said leg, said bushing being fixed in contacting, immoveable relation to said cylindrical inside surface of the cutter wheel, and said inner end surface of said cutter wheel being positioned in juxtaposition to said annular end surface of said spindle.