GB520088A - Improvements in or relating to rock drilling equipment - Google Patents

Abstract

520,088. Rock drills. HAIG, D. M. (Eidco, Inc.), Oct. 12, 1938, No. 29484. [Class 124] In a rock drill the bit comprises a hollow head 10 flattened on opposite sides and having a conical depression providing diametrically opposed arcuate reaming edges 17, and one or more cutter portions 13 within the conical depression. The reaming edges lie substantially on the same circle, and the under surface of the head 10 may be of double conical formation, as shown at 37. The cutters 13 may be elliptical, straight sided with chisel edges 16, or they may be of cross, rose, or other shape. They may lead or follow the reaming edge in the cutting operation, and they may have tapered shanks 14 for attachment to the head by friction joints, or they may be attached by the usual screwthreaded connections. They may be made in two or more axially split parts, and their plane surfaces may be at equal or unequal angles to their axes. They may be formed with fluid passages which discharge on their opposite sides. The head 10 may be removed from the tapered portion 2 of a drill rod by means of a U-shaped wedge member 21 which engages astride the rod and fits between the bit head and inclined portions 22 on opposite sides of an integral or rigidly fixed buttress ring 20. The drill rod comprises a number of sections 1 provided at each end with a female member 5 or a serrated male member 2 adapted to make a friction joint with a corresponding male or female member on the next section or on a coupling member 7. Each male member 2 may have a steep portion O with inclined shoulders 4.on opposite sides to provide angular flat portions 3 adapted to accommodate a wedge for separating the two parts. The serrations may be parallel to the axis of the rod or bit, inclined thereto, or crossing each other, and the inside of the sockets may be made softer relatively to the outer surfaces and cutting edges.