| 摘要 |
PURPOSE:To obtain readily a shrink cylinder body that can be diametrically shrinkable, by putting a cylinder of a thermoplastic material on a molding pipe, whose outer circumferential surface can be circumferentially expanded, with the pipe in the constricted state, and expanding said outer circumferential surface to stretch the cylinder. CONSTITUTION:The molding pipe body 2 consists of an assembly of a plurality of segments 4 that are radially arranged. When the segments 4 are radially constricted, their tapered tips meet along a line and their outer circumferential surfaces make approximately a circle. The longitudinal opposite ends of the segments 4 are provided with engaging slots so that expanding and constricting members 2, 3 in the shape of a taper cone can be inserted longitudinally into said opposite ends. The outer circumference of the segments 4 is provided with grooves, in which springs 8 are put. The cylinder 1 of a thermoplastic material is put over the outer circumference of the molding pipe body 2, and the outer circumference of the molding pipe body 2 is expanded to obtain the desired cylinder. |
