GB550100A - Improvements in or relating to drills for mixed excavation - Google Patents

Abstract

550,100. Boring earth and rock. ORKIN, A. Z. May 16, 1941. Nos. 6355/41 and 1255/42. [Class 85] Means for drilling through mixed strata comprises a pneumatic motor 22 adapted to rotate and recipro cate a suitable drill, and to be raised or lowered therewith within a bore-hole lining 26 by means of a cable 24, compressed air being led to the motor through a flexible tube 25, and also passing through channels in the drill to carry spoil up through the lining 26. The lowermost lining section has a liner 27 with vertical slots closed below and outwardly flared at their upper ends, the casing of the motor 22 having bars engaging solid slots to hold the lining and motor 22 against relative rotation when the motor is in its lowered position. The drill may be of beryllium copper alloy, hard aluminium alloy, brass or steel, and may comprise a cylindrical part 12, Fig. 1, for connection with the drill rod, an upper portion 13 with radial passages for the compressed air, and preferably with wings 21 to impart turbulance to the air stream, a lower frustum 14 with a cross cutter 15 on its lower face and cutting blades extending up the inclined wall thereof, and between the frusta, sectors 16 pivoted at 17 and provided with cutting edges 18, means being provided whereby the sectors 16 may be moved outward to bring the cutting edges into working position, or inwards to allow passage. up through the lining. In another form of drill, Fig. 5, the sectors 16 are omitted, the piston being connected by a cylindrical part 45 by which the hole is smoothed. The top of the lining 26 may be provided with a radially movable canopy 31 and conduit 32 leading to a cyclone &c. separator 33 which removes the spoil from the air stream.