| 摘要 |
PURPOSE:To eliminate the wrinkle or the sag of the titled tube perfectly by a method wherein the synthetic resin tube is inserted into a metallic bent tube in a state that a part of it is softened and the synthetic resin tube is pulled while pressurizing the inside thereof. CONSTITUTION:A part of a synthetic resin tube which is corresponding to the bent position of a metallic bent tube 4 is inserted into a heating furnace 3. The one end area of the synthetic resin tube 1 is heated and softened by heating it. The softened synthetic resin tube 1 is taken out of the heating furnace 3 and is inserted into the metallic bent tube 4 quickly from the softened end 11 thereof. Air is blown into a plug 22, fitted to the end 12 of the synthetic resin tube 1 in such state, through a through-hole 22d to make the internal pressure of the synthetic resin tube positive and expand the softened part of the synthetic resin tube 1 into a cylindrical form. When the synthetic resin tube 1 comes into the cylindrical form, pulling equipments, such as hoists or the like, are connected to the engagement parts 21c, 22c of the plugs 21, 22 fitted to respective ends 11, 12 of the synthetic resin tube to pull respective ends 11, 12 axially under a state that the inside of the synthetic resin tube 1 is being pressurized. |
