GB753726A - Improvements in rotary earth boring apparatus - Google Patents

Abstract

753,726. Earth -boring apparatus HARINCK, P. J. Jan. 12. 1954 [Jan. 19, 1953], No. 824/54. Class 85 In a rotary earth-boring apparatus a cross-head 15 is connected to and reciprocated over a short distance along the axis of a bore hole by the piston rods 12, 13 of hydraulically actuated piston-cylinder motors 8 9. Rotatably mounted on to move with, the cross-head 15 is a chuck assembly H, which is automatically released by hydraulically-actuated means from a drill pipe 40 between movement of the chuck towards, and away from, the borehole. The chuck is rigidly connected to a casing 16 and a sleeve 28, and between the chuck and the casing is a chuck actuator 18. The actuator 18 is so shaped as to form with the casing two liquid tight annular chambers 21, 22, and to cause the jaws 46 of the chuck to close about the pipe 40 on movement of the actuator towards the borehole. The corresponding interior spaces 58, 58a. and 63, 63a of the cylinders 8, 9 are interconnected. The spaces 58, 63 are connected by passageways 56, 55, 57, 57a and passageways 61, 60, 62, 62a 64 to the chambers 23 and 21, respectively. When the pressure in the spaces 63, 63a is in excess of those in spaces 58, 58a, the actuator 18 moves, relatively to the casing 16, towards the borehole so causing the clutch jaws 46 to lock on the pipe and vice versa. The sleeve 28 passes through and has a splined connection with' a driven bevel gear 32 60 that the pipe 40 is rotated as it is advanced by the piston-cylinder motors. The admission and exhaust of liquid from the cylinders 8, 9 may be manually or automatically regulated.