Patent GB-655256-A (GB)
Title: Improvements in or relating to apparatus for rotating cylindrical bodies
IPC: E21B19/16
Filed: 1947-06-18
Abstract: 655,256. Screwing-up and unscrewing screws; chucks and sockets. STANDARD OIL DEVELOPMENT CO. June 18, 1947, No. 16148. Convention date, Aug. 22, 1946. [A Specification was laid open to inspection under Sect. 91 of the Acts, Feb. 17, 1948.] [Class 83 (iii)] Apparatus for rotating a cylindrical body, e.g. when screwing and unscrewing pipe sections, comprises an arm 211 having its outer end formed as one jaw member to which is pivoted at 213 a movable jaw member 212, the jaw members when closed providing a cylindrical opening within which is rotatably mounted a diametrically split ring 214, 215, each half of which is retained in one of the jaw members when in the open position, the halves of the split ring co-operating when the jaws are closed to form a ring member embracing the cylindrical body, the split ring being provided with an elastic lining 209 to grip the body, and the halves of the split ring being provided with co-operating circumferential flange portions 220 formed with external teeth to form a gear wheel which is driven by means of a train of gears from a prime mover 227 on the arm 211. The halves of the split ring are provided with upper and lower screw threads 216, 218 co-operating with upper and lower screw threads on the inner walls of the jaw members, the split ring being caused to move axially in either direction as it is rotated, shoulders 217 provided on the screw threads 216, 218 being adapted to engage shoulders 225, 226 on the jaw members so as to prevent rotation of the split ring beyond a predetermined amount in either direction, the shoulders being so arranged that the rotation of the split ring is stopped when the diameter along which the ring is divided coincides with the direction line of the jaw members. Each half ring is retained within the corresponding jaw member by means of pins 221, 222 engaging grooves in the jaw members. The jaw members are locked in the closed position by means of a member 237 pivotally mounted on the fixed jaw member and provided with a cam surface 238 which is adapted to be engaged by a hydraulically-actuated wedge 239, a spring 245 being adapted to retract the wedge on release of the hydraulic pressure. The arm 211 is hinged at c to an arm 250 which is rigidly mounted on a tubular pivot member of a column d, capable of being rotated and moved longitudinally with respect to a fixed inner tubular member by hydraulic means. In a modification, Fig. 7, the split ring is formed with a tapered seat 276 adapted to be engaged by the tapered outer surfaces of slip members 277, 278 which embrace and grip the cylindrical body, the slip members being pressed radially inwardly and towards the larger diameter of the seat 276 by means of springs and the split ring being provided with a flange 290 to limit the movement of the slip members. The parts of the split ring are provided with inwardly-directed abutments 289 against which the ends of the slip members abut to prevent rotational movement of the same with respect to the split ring. Alternatively, the abutments may be formed as shoulders projecting outwardly from the slip members and engaging in grooves in the tapered inner surfaces of the split ring. In a further modification, Figs. 9 and 10 (not shown), the upper and lower screw threads provided on the tapered split ring and those provided on the walls of the jaw members are of dovetailed section.