GB795166A - Improvements in or relating to the fabrication of hollow airfoil blades - Google Patents

Abstract

795,166. Making airfoil blades; angular bending. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. Sept. 26, 1956 [Sept. 29, 1955], No. 29373/56. Classes 83 (2) and 83(4). A machine for forming hollow airfoil blades comprises a mandrel shaped as an airfoil, a pair of forming rolls having parallel axes, means for supporting said rolls adjacent the nose of the mandrel but spaced sufficiently therefrom for a blade blank to be placed between the mandrel nose and the rolls, means for moving said mandrel and a blade blank between said rolls, and means for applying pressure to said rolls for pressing the blade blank against the sides of the mandrel as the mandrel and blank move between the rolls. A blade blank 28 placed on parallel rolls 24 is pressed therebetween by an airfoil-shaped mandrel 20 moved downwardly by fluid-pressure means 23, fluid-pressure means 27 at the ends of each roll 24 forcing the blank 28 into close contact with the sides of the mandrel 20 as the mandrel passes between the rolls. The formed blank is then removed from the mandrel and its trailing edges are pressed together, welded and then machined and ground to remove welding burrs and inequalities. The airfoil blade thus formed is then mounted on the rotor of a centrifugal fan. The mandrel 20 may be of organic material, e.g. wood, for cold forming or of metal for hot forming. The mandrel may be formed of spaced-apart sections 20a, Fig. 6. Instead of the rolls 24 engaging the blank, rolls 30, Fig. 7, backed up by the rolls 24, may do so. A further pair of rolls 34 may be mounted below the rolls 24, Fig. 8, or 30, to press the blank on to the mandrel 20 to reduce spring- back. A tapered mandrel 46, Fig. 10, of airfoil section may be used, in which case the ends of the mandrel 46 may be moved at different rates by fluid-pressure means 49, 50. A cam 64 on a piston-rod 52 of the means 50 may actuate a valve 62 controlling the other fluid-pressure means 49. Independent rolls 70, 71, 72 on common shafts, Fig. 14, or independently mounted urged rolls 70a, 71a, 72a, Fig. 15, may replace the rolls of Fig. 10.