Earth-boring bit having improved cutting structure

An earth-boring bit comprising:

• a bit body;
• at least one cantilevered bearing shaft depending inwardly and downwardly from the bit body;
• a cutter mounted for rotation on the bearing shaft, the cutter including a plurality of cutting elements arranged in circumferential rows on the cutter, the rows including a heel row;
• the cutting elements in the heel row including chisel-shaped elements having crests, the crests of a portion of the cutting elements being oriented transversely to the axis of rotation of the cutter, the remainder of the cutting elements in the heel row having crests generally aligned with the axis of rotation of the cutter, all of the cutting elements in the heel row having approximately the same projection from the heel surface of the cutter.

An earth-boring bit comprising:

• a bit body;
• at least one cantilevered bearing shaft depending inwardly and downwardly from the bit body;
• a cutter mounted for rotation on the bearing shaft, the cutter including a plurality of cutting elements arranged in circumferential rows on the cutter, the rows including a heel row on the heel surface of the cutter;
• the crests of a portion of the cutting elements in the heel row being oriented transversely to the axis of rotation of the cutter, the remainder of the cutting elements in the heel row being axisymmetric in configuration, all of the cutting elements in the heel row having approximately the same projection from the heel surface of the cutter.

An earth-boring bit comprising:

• a bit body;
• at least one cantilevered bearing shaft depending inwardly and downwardly from the bit body;
• a cutter mounted for rotation on the bearing shaft, the cutter including a plurality of cutting elements arranged in circumferential rows on the cutter;
• the cutting elements in the at least one row including at least one chisel-shaped cutting element having a crest oriented transversely to the axis of rotation of the cutter, the remainder of the cutting elements in the at least one row having a configuration different from the chisel-shaped elements having crests oriented transversely to the axis of rotation of the cutter with no crest, all of the cutting elements in the row having approximately the same projection from the surface of the cutter.

An earth-boring bit comprising:

• a bit body;
• at least one cantilevered bearing shaft depending inwardly and downwardly from the bit body;
• a cutter mounted for rotation on the bearing shaft, the cutter including a plurality of cutting elements arranged in circumferential rows on the cutter;
• the cutting elements in at least one row including chisel-shaped elements having crests, the crests of a portion of the cutting elements being oriented transversely to the axis of rotation of the cutter, the remainder of the cutting elements in the at least one row having crests generally aligned with the axis of rotation of the cutter, all of the cutting elements having approximately the same projection from the surface of the cutter.

An earth-boring bit comprising:

• a bit body;
• at least one cantilevered bearing shaft depending inwardly and downwardly from the bit body;
• a cutter mounted for rotation on the bearing shaft, the cutter including a plurality of cutting elements arranged in circumferential rows on the cutter;
• the crests of a portion of the cutting elements in at least one row being oriented transversely to the axis of rotation of the cutter, the remainder of the cutting elements in the at least one row being axisymmetric in configuration, all of the cutting elements having approximately the same projection from the surface of the cutter.