GB1474848A - Pipe bending machines - Google Patents

Abstract

1474848 Bending tubes TSENTR NI INST TEKHNOLOGII MASHINOSTROENIA 30 May 1975 23721/75 Heading B3E A pipe bending machine comprises a rotary member to which one end of the pipe is attached, a displaceable member to which the other end is attached, and a connection between the members such that when the displaceable member is displaced to move the pipe axially and rotate the rotary member so that the pipe is bent, the pipe is subjected to compression between the members. Fig. 1 shows an embodiment before bending, and Fig. 5 is a part sectional view after the bend is made. A bed 1 supports a crosshead 3 on slideway 2, a carriage 7 by wheels 10 and rails 11, and bearings 31 (one shown) for a shaft 30. The crosshead 3 is displaceable by cylinders 4. The carriage 7 is movable along its rails by motor 8 and drive 9, and supports a tube abutment plate 17 on slide 18, the plate having tube grips 20 and being reciprocable by screw and nut mechanism 14, 16 driven by motor 12. Relative longitudinal movement of the crosshead 3 and carriage can be restrained by rotation of two armed member 25 so that recesses 28 in its ends engage rods 23 on the crosshead between collars 24. The bending head comprises a pipe clamp 35 and abutment plate 36 mounted on a support 34 movable radially along a forked arm 32 on shaft 30 by screw 38 and motor 39. Discs 41 (one shown cut-away) biased by weights 48 are secured to shaft 30, and are connected to crosshead 3 by chains 44 secured to portions 42 of the discs, so that the chains are radially further from the axis of shaft 30 than the tube 19. In operation the position of bearings 31, the position of support 34 radially of shaft 30, and the parts 42 of discs 40 are chosen to suit the bend required. A tube is held in grips 20, and the carriage is advanced to abut the tube against plate 36, the tube running a guide roller 6 and thrust rollers 45. Arm 25 is then engaged between collars 24, and screw 14 driven to put the tube under compression. Clamp 35 is applied, and cylinders 4 are then extended to advance the tube, rotate the bending head, and bend the tube, which remains under compression sufficient to prevent thinning of the tube wall on the outside of the bend, since chains 44 prevent the shaft 30 rotating as much as it would if free. Clamp 35 is then released, so that weights 48 fall to cause the tube to advance out of the machine. An induction heater 49 and spray cooling unit 50 are incorporated.