Patent GB-1430251-A (GB)
Title: Pipe bending system
IPC: B21D9/04
Filed: 1973-04-05
Abstract: 1430251 Bending pipes CRC-CROSE INTERNATIONAL Inc 5 April 1973 [6 June 1972] 16404/73 Heading B3E A method of bending a pipe about a die includes cradling the pipe opposite the die in a first member, cradling another portion of the pipe in a second member, positioning a flexible mandrel having elongated inflatable bags within the pipe, closing clamps secured to each member around the pipe, inflating the mandrel bags, and applying forces to the first member adjacent the die and remote therefrom to bend the pipe. The apparatus described is for bending sections of cross-country pipeline, and has a main frame consisting of side plates 21, (22) connected by transverse members 23, 24, 25. The frame rests on the ground at one end, and upon endless tracks 26, (27) at the other. The bending die 30 is convex in longitudinal section and concave in transverse section, and is located by spigot 30 on and secured to a cast iron backing shell 28 supported on the transverse members 24. The first pipe cradling member is an elongate shoe 32 which is suspended at one end by shafts 35 and hydraulic piston and cylinder devices 37, 38 from the transverse members 24. At the other end, a shaft 52 on the member is held in T-pieces 48, shafts 51 of which are connected to the transverse members 25 by hydraulic jacks 44, 45. Fig. 5 shows in transverse section the clamp on this member, comprising arcuate plates 75, 76 pivoted to the member and closable about the pipe 73 by straightening past dead centre of toggle links acting between plate 76 and an extension 78 of plate 77. The links are operated by jack 80 on plate 76. The second pipe cradling member is a shoe 57 supported by a shaft 59 on a bearer 60 located between arms 61 on a shaft 62 on the main frame. The bearer and shoe can be raised by a wedge 64 movable by jack 65 over a plate 63 supported by transverse members 23. The clamp 66 on this shoe is of lighter duty than clamp 72, and its arcuate plates are closable by direct action of an hydraulic jack. The pipe can be manoeuvred on rolls 95 on the main frame and rolls 91 on a tongue 86 on member 32, by which tongue the whole apparatus can be manoeuvred over the ground. The mandrel 112 is as described in Specification 1,430,253, and is located opposite die 30. Further expansible internal pipe supports 110 (one shown) are provided for each end of the pipe, being either attached to mandrel 112, or slung from davit devices 114, 115. A winch 99 is provided in the main frame to move the pipe along once it is on rollers 91, 95. To bend a pipe section, it is fed, e.g. by a crane, into the frame and laid on rolls 91, 95. When it is the correct position, the cradling members 32, 57 are raised to abut the pipe (and lift it off the rollers 91, 95) the clamps 66, 72 are tightened, and the mandrel 112 located and expanded. If the pipe section ends at about either clamp, the additional support 110 at that end is installed and expanded. Pressure fluid is then admitted to jacks 37, 38, 44, 45 through a sequence value ensuring that adequate pressure is built up in jacks 37, 38 before jacks 44, 45 operate to bend the section. The winch 99 may be used to haul the pipe section along if a further bend is required at a different part of the section. Specification 1,430,252 is also referred to.