GB765179A - Improvements in the manufacture of tubular metal bends and fittings - Google Patents

Abstract

765,179. Making pipe elbows, return bends, etc.; bending; stamping. HUET, A. March 3, 1952 [March 2, 1951], No. 5494/52. Classes 83 (2) and 83 (4). A localized thickening or bulge in the wall of a tube is obtained by bending the tube with localized heating in the region to be bulged or upset. In an example, in which a U-tube with a 180 degrees bend is to be made with localized thickening on the outer part of the curve, a tube a, Fig. 1, is bent by any means beyond the required 180 degrees. The outer portion c, and two inner portions AB-CD are then heated and the limbs are separated while the tube end is clamped in a die e, Fig. 2, which confines the outer radius so that the metal is upset and thickened. A straight tube may be similarly bulged by bending and subsequently straightening and larger bulges may be formed by repeating the operations. In another example in which the tube is required to be bulged the die member e, Fig. 6, has the shape of the required bulge. In other examples a U-tube which originally has a 180 degrees bend has the limbs separated in similar dies to form the bulge or thickening and the tube is subsequently restored to 180 degrees by any bending means. In a further example, the tube may be clamped in hinged dies e<SP>1</SP>, e<SP>2</SP>, Fig. 18, the shape of the dies confining the outer region of the tube so that it is upset and thickened. In other examples one or more bulges c, Fig. 17, may be formed by localized heating in the region of the required bulge. By heating one of the regions AB or CD more than the other an asymmetric bulge may be formed. The bulge may be subsequently opened out to form a pipe connection.