GB1100794A - Reversing tool for screwing-up and unscrewing well pipes - Google Patents

Abstract

1,100,794. Screwing-up and unscrewing pipes. C. C. BROWN, 21 March, 1966, No. 12400/66. Heading B3N. A tool for inserting into well pipes for screwing up or unscrewing two sections C1, C2, Fig. 1, comprises a mandrel M, pipe gripping units 17, 18 mounted on the mandrel so as to engage each side of the screwed joint J, and gear means 45-47 which are operable by rotation of the mandrel, to simultaneously transmit opposite rotational forces to the units. Each gripping unit comprises a body 20 supported on the mandrel, two series of rollers 38, carried on shaft 37, and a pair of shoes 27, Fig. 5, each of which has a smooth surface 32 and toothed portions 34. Internal gear 47, Fig. 9, has projecting end portions 48, 49, Fig. 1, the former having a splined connection 50, 51 with body 20 of the gripping unit 17. Gears 46 are located in slots 53 forming a spider 52 in the lower body 20, Fig. 4. In operation, with mandrel M connected to a shaft P, Fig. 1, the tool is positioned in the well pipe. Sections 32 on the shoes 27 engage the bore of the pipe, Fig. 5, and as shaft P is rotated, this movement is transmitted through gears 45-47 and spider 52 to shoes 27 of the lower unit 18. The shoes are pivoted, and teeth 34 bite into the wall of casing section C2, Fig. 7, (not shown), and as this section is fixed in the well, further rotation of unit 18 is stopped. Gear 47 drives the body 20 of upper gripping unit 17, and the shoes 27 of this unit are pivoted, so that teeth 34 bite into the wall of the easing section C1 Fig. 6 (not shown). Continued clockwise rotation of shaft P will cause continued counterclockwise rotation of the upper casing C1, to thus unscrew the latter from casingC2. When a joint is to be tightened, the tool is turned end for end.