GB1452524A - Device for rotating or twisting a pipe - Google Patents

Abstract

1452524 Screwing up and unscrewing pipes WEATHERFORD OIL TOOL GmbH 19 Dec 1973 [19 Dec 1973] 58943/73 Heading B3N [Also in Division E1] A device for rotating a pipe 10 comprises a ring gear 1 coupled to a drive pinion 2 and coaxially disposed between two annular guide plates 6, the ring gear and guide plates each having a cut-out portion 3, 13 of the same width, clamping jaws 9a, 9b radially movable relative to the guide plates for gripping the pipe, cams 7a, 7b arranged on the inside of the ring gear for displacing the clamping jaws inwardly into engagement with the pipe, each cam and its respective clamping jaw being at a different axial location so that each cam can only contact its respective clamping jaw, and means (20, 22), Fig. 6 (not shown), for centring the pipe within the ring gear with the cut-out portions of the ring gear and guide plates aligned. The ring gear is rotated through 180 degrees relative to the guide plates to form a closed rigid ring-shaped structure and to cause the clamping jaws to grip the pipe; subsequent rotation of the ring in the same direction rotates the pipe. The alignment of the cut-out portions 3, 13 in the ring gear and guide plates with a cut-out portion (40) in an outer casing (31) for initial fixing of the device around the pipe, the locking of the guide plates with the ring gear after rotation of the ring gear through 180 degrees in a selected direction to form the closed ring structure, and the subsequent rotation of the pipe in the same direction are achieved by means of slidable bolts (36 and 38), Fig. 3 (not shown), in one guide plate 6 and the ring gear respectively, cam surfaces (32) mounted on the interior of the casing, and stop bushes (34) slidably receiving the bolts (36).