GB722019A - Improvements in method of and means for forming bellows - Google Patents

Abstract

722,019. Making bellows. PETERS, M. F. Sept. 24, 1951 [Dec. 13, 1950], No. 22259/51. Classes 83 (2) and 83 (4). A method of forming an annular metal bellows membrane to a concave-convex shape comprises clamping the inner and outer margins of the membrane and applying fluid pressure to stretch the unsupported area of the membrane between the margins-beyond the elastic limit of the membrane material. A membrane 1 is formed by clamping the margins 3 and 4 between the jaws 9 and 10 of a clamping device comprising upper and lower members 5 and 6 respectively which form a chamber on each side of the clamped membrane. Fluid under pressure enters the lower chamber from a duct 8. The upper chamber has a support 7, a trigger member 12 and a vent 11. The membrane is deformed until it contacts the support 7 then it is annealed and the forming pressure np applied to form the membrane. Similarly a membrane 1<SP>1</SP> is formed to a different curvature after replacing support 7 by a support 71 and the jaws 9, 10 by jaws 91, 10<SP>1</SP> and applying a forming pressure n<SP>1</SP>p. The support 71 is equal in length to support 7 plus the distance between two adjacent margins 4 and 41 (Fig. 2), and has a smaller diameter than 7 by twice the thickness of the metal. The inner diameter of the jaws 91 and 101 is equal to that of the jaws 9 and 10 minus twice the thickness of the metal. The curved surface of the membrane and the width of the margins may be varied throughout their perimeter to compensate for unequal distribution of shearing forces and bending moments induced in the membrane when they are assembled into a bellows as shown in Fig. 2. Each membrane may be formed in sections and the sections joined together to form the complete membrane.