GB903695A - Improvements in or relating to machines for and methods of bending tubes - Google Patents

Abstract

903,695. Angular bending. PRECISION AIRCRAFT (READING) Ltd., and PALLANT, W. March 18, 1960 [Dec. 29, 1958], No. 41898/58. Class 83 (4). A method of bending a tube comprises applying a bending moment to the tube and rolling the wall of the tube in a circumferential direction to re-distribute the material of the wall between the inside and outside of the bend. A tube 48 to be bent is clamped at one end between an internal split disc 49 expanded by a conical pin 50 and an outer ring 52, the clamping means being carried by a bracket 47 adjustable along a beam 46 on a machine base 10. Three adjustable rollers 25 surround and engage the tube 48 and are carried by a cage 21 rotated around the tube by a motor 30, supported on bearings in a bearer structure including two plates 27. This structure is adjustable by a lead screw 32 along bars 15, 16, 17, 18, connected at their ends by plates 13, 14 to form a jib 12 swingable about a pivot 11. A disc 45 supporting the tube 48 internally against the rollers 25 is supported by a rod 44 on which is mounted a second tube support disc 53, the rod 44 being carried by a beam 42 extending from the bearer structure 27 and adjusted so as to be at right angles to the bars 15-18. In operation the jib 12 is moved about its pivot 11 by a pinion 36 engaging a fixed arcuate rack 37 and driven by a hand wheel 39 or from the motor 30 so that the rollers, as they rotate around the tube 48, move slowly therealong to impart a bending moment on the tube and at the same time move metal from the inside to the outside of the bend. To produce tubes bent about more than one axis the table 10 may be rotatable about an axis at right angles to the pivot 11, the beam 46 being adjustably secured to a fixed part of the machine instead of to the table.