| 摘要 |
PROBLEM TO BE SOLVED: To prevent a flat rigidity of a rubber ring faucet from decreasing by not collapsing a rib, to surely connect a spigot of a tube to the faucet by reducing unevenness of an inner diameter of the faucet. SOLUTION: A method for working a radially enlarged faucet of a tube with inner and outer smooth waves comprises the step of heating to soften the end 12d of the tube with the inner and outer smooth waves. The method further comprises the steps of radially enlarging the end 12d of the tube by third enlarging/contracting die 60 in a state in which a pressure hot gas is supplied to spaces 28a, 40 between an inner layer 18 and an outer layer 16 of the softened end 12d, thereby forming the rubber ring faucet 14. Since the end 12d of the tube is radially enlarged in a state in which the spaces 28a, 40 of the end 12d are pressurized, a rib 28 of the end 12 of the tube when the end 12d is radially enlarged is not collapsed by an elastic force of the layer 16. Since the rib 28 is not collapsed, an inner peripheral surface 14a of the faucet 14 is formed smoothly, and the unevenness of the inner diameter of the faucet 14 is reduced. COPYRIGHT: (C)2003,JPO |
