GB816625A - Improvements in or relating to apparatus for bending tubes - Google Patents

Abstract

816,625. Angular bending. HUET, A. June 7, 1957 [July 3, 1956; July 6, 1956; July 11, 1956], No. 18262/57. Class 83 (4). Apparatus for bending tubes includes a punch for exerting pressure on a tube to be bent kept at a suitable temperature gradient thereacross, a roller to each side of the punch to back the tube being bent, a partitioning member in the tube to divide it into two compartments and a pipe inside one of said compartments to supply coolant thereto. A tube a to be bent is pressed by a piu ch d against backing rollers b, c while heated at that part A which will form the inside of the bend and cooled at that part which will form the outside of the bend. The tube a is divided into two compartments by a longitudinal strip h, is heated at A before bending and is kept hot there by a flame tube inside the tube a, or, as shown, by a flame tube l or hot gas in a bore k in the punch d, and is cooled in the other compartment by atomised water or very humid air from a pipe g in the tube a. The pipe g may be integral with the strip h and hinged at i and j. On completion of the bending the punch and the tube can be cooled by liquid coolant in the bore k. The punch d is wide enough to support the whole of the bend and is formed with a groove to accommodate the tube a which groove bulges at e to allow thickening of the inside of the bend. The tube a is also supported laterally at its cooled part by cheeks f<SP>1</SP>, f<SP>2</SP> on the punch. An ejector m which may comprise several segments, facilitates withdrawal of the bent tube from the punch. The bent tube may be further shaped by a die shaped to the outside bend of the finished elbow, the outer part of the bend being heated and the inner part preferably cooled. This die may include a tube ejector. Specification 792,889 is referred to.