| 摘要 |
PROBLEM TO BE SOLVED: To prevent a joint joining composite tubes together from projecting into them, prevent their inner and outer tubes from peeling off while their ends are heated up, and design the joint to be applicable to various tube diameters. SOLUTION: This joint structure, which is for composite tubes each comprising a metallic tube 7 having an inner tube 8A on its inner surface and an outer tube 8B on its outer surface, both made of synthetic resin, comprises a tubular joint body 9 of the same material as these inner and outer tubes 8A and 8B adapted to be disposed over the end periphery of the inner tubes 8A whose end only is projected from the end of the metallic tubes 7 and over the end periphery of the outer tubes 8B, and electric heating elements 10 buried in the joint body 9. The joint body 9 has, on its inner surface, a step 9A against which the end faces of the metallic tubes 7 and outer tubes 8B are pressed. The electric heating elements 10 are energized to heat up or melt up the joint body 9 and the ends of the inner and outer tubes 8A and 8B into one united body. |
