| 摘要 |
PROBLEM TO BE SOLVED: To enhance the tube manufacturing speed without increasing stress applied to belt members and following them to an established tube bent part by spirally winding and joining a wide-width belt member formed by jointing two or more long belt members having joint parts in their both side edges. SOLUTION: A belt member 100 forms joint parts 100A, 100B engaged by stacking their insides/outsides with each other in the both sides. The front edge side joint part 100A is so formed that the base of a front end projecting beam 102A is enlarged, a recess groove 100 is provided from its inside, and an overhang part 112 is linked therewith. The rear edge side joint part 100B is so formed that an overhang part 114 is extended from a rear end projecting beam 102B and a projecting beam 116 engaged with the front edge side joint part 100A recess groove 110 is provided toward the overhang part 114 end. To form a wide-width belt member by joining the adjoining belt members 100 with each other, the front edge and the rear edge are stacked together, the rear edge side joint part 100B is stuck to the front edge side joint part 100A, and the projecting beam 116 is fitted in the recessed groove 110. |
