| 摘要 |
PURPOSE:To reduce the using quantity of synthetic resin and facilitate manufacture by constituting two edge plates from the joint of a winding core formed at the center part and an auxiliary winding core part. CONSTITUTION:Each edge plate 3, 5 is prepared by successively heating a thin long sheet prepared from a thin roll sheet made of the thermoplastic synthetic resin such as polyethylene and vinyl chloride resin, and shaping a winding core 2, auxiliary winding core 4, etc., by metal molds and then separating said cores. The annular winding core 2 having a nearly U-shaped section is projectingly shaped in the core part of the edge plate 3. A tape is wound onto the outer part 2a of the the taking up core 2. The auxiliary winding core 4 is fitted onto the inside diameter part 2b. Though the other edge plate 5 is prepared into a nearly same shape to one edge plate 3 similarly in the above- described, the outside diameter part 4a of the auxiliary winding core is lightly fastening-fitted onto the inside diameter part 2b of the above-described edge plate 3. With such constitution, the rigidity of the core 3 part is increased, and the using quantity of synthetic resin can be reduced, and even if material is thin, breakage can be reduced.
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