GB1215967A - Well pipe tongs - Google Patents

Abstract

1,215,967. Well pipe tongs. BYRON JACKSON Inc. 12 Nov., 1968 [4 Dec., 1967; 17 June, 1968], No. 53651/68. Heading B3N. Tong apparatus for making up and breaking out joints in well pipes comprises a back-up tong assembly, Fig. 5, that releasably holds a length of well pipe protruding from a well bore and a tong assembly, Fig. 12, which releasably holds and rotates a co-operating length of pipe. The back-up tong assembly comprises a support structure 202 connected to a stationary ring 217 by ears 211. Jaws 230 are slidably mounted in a ring (220), Fig. 6 (not shown), which comprises generally triangular plates 221 and 222. The jaws slide in pads 256 (257) which allow the jaws to cock relative to them. A ridge 251 of the ring 217 forms a cam whereby the jaws 230 can be positively moved inwardly or outwardly by cam followers 252 and 253. Follower 253 is removable to allow the removal of the jaws 230. To move the jaws the ring (220) is rotated by a double acting ram 266. The ram can be position at abutment 282 or abutment 281 so that the pipe 2 is gripped such that any tendency to rotate during making up or breaking out presses the jaws harder against the pipe. Pivotal movement of the ram is by a double acting ram (283), Fig. 11 (not shown), operating on the pivoted end of the ram 266 via a lost motion means and a lever. The ram 266 is locked in position by a latch pin 289 engaging either of openings 290 (292), the latch pin is automatically releasable from the openings. The tong assembly comprises an inner ring (410), Fig. 13 (not shown), in which jaws 411 are slidably mounted, and a driven outer ring (409). The driven ring has a cam ridge by which cam followers 443 and (452) positively move the jaws into and out of engagement with a pipe 1. Inner ring (410) has to be kept stationary to obtain movement of the jaws, this is achieved by a brake band 470 which has anchors 473 and 474 which engage pins 475 and 476 which project down from a stationary support plate 477. When the jaws are in engagement with the pipe both rings (410) and (409) rotate together. To stop excessive movement of the jaws in either direction a reverse stop means is incorporated in the tong assembly. The stop means comprises a stop member 482 which can be positioned in either of two positions in which a member 481 engages the stop member 482 to stop relative movement between the inner and outer rings. Movement of the stop member 482 from one position to the other is caused by an abutment means 500 which has a fluid operated retractable projection which engages in an arcuate depression, in member 482, and which has arcuate wall sections 514 and 515.