Point-attack bit

Abstract

A point-attack bit retained for rotation in a block bore, and used for removing material from a mine face. The bit has an elongate shank, and a head integral and coaxial with the shank, the head including a plurality of peripherally spaced, laterally projecting vanes extending generally longitudinally of the bit. Each vane is substantially triangular with a narrow leading end and a wider trailing end, and has sides that extend from the leading end to the trailing end. One of the vane sides has a different angle with respect to the longitudinal axis of the bit than the other vane side to provide different transverse forces on the vane sides upon contact with material being mined to effect a positive turning of the bit upon picking of the mine face. More particularly, the vane sides extend from the leading end to the trailing end on opposite sides of a longitudinal plane passed through the longitudinal axis of the bit and the leading end of the vane so that one vane side has a different included angle with respect to the longitudinal plane than the other vane side.

Dependencies are inferred from the claim text.