GB865879A - Improvements in machines for rotary drilling - Google Patents

Abstract

865,879. Boring earth. KVELLO-AUNE A. G., and TROFTEN, P. F. Nov. 25, 1959 [Nov. 26, 1958], No. 40067/59. Class 85. In a rotary drilling apparatus, the drill string is rotated by either or both of two chucks spaced axially along the string, the chucks being independently displaceable along the string so that whilst one chuck, operative for the time being, is coming to the limit of its feed movement, the other, temporarily inoperative is moved to the beginning of its feed movement to take over the drive of the string without interrupting its rotation Figs. 1, 2 joined end to end, show identical upper and lower chucks 2, engageable with a drill string 9 and driven by a motor 72 on a housing 7 carried by a frame 80. The chucks comprise a stationary outer casing having a recessed wall 40 forming, with a sleeve 34 an annular cylinder for a piston 38 attached to the sleeve, ports 44, 46 admitting pressure fluid above and below the piston. The axial movements of the sleeve 34 are transferred by bearings 30, 32 to a tapered member 28 which bears on wedge-shaped toothed pipe-engaging dogs 10. Roller bearings 16, 18 and the bearings 30, 32 permit the pipe-gripping means to be rotated to the outer casing and sleeve 34, the rotation being effected by the motor 72 which drives, by chain and sprocket 70, a hollow shaft 21 in which a hollow shaft 20, attached to the clutch parts, is telescoped, driving splines 64 being provided. The chucks are attached to tubular members 3, 4 which have an annular piston 56 secured thereto, the piston working in a cylinder 60 in casings 5, 6 having ports 59, 61, 591, 611 for the supply and exhaust of pressure fluid, the chucks being thus independently adjustable axially of the drill string, and provided with the requisite downward thrust for the drill feed. The machine may be provided with a known time controlled valve system, so that it operates on a timed cycle. The removing of pipes from the bore may also proceed continuously. The cylinder 60 may be replaced by two or more hydraulic units spaced around the drill pipe, and one motor 72 may be provided for each chuck. In a modification, one chuck only is axially movable, this chuck taking over the drive, without feed, whilst the other chuck is being axially re-positioned.