PURPOSE: To simplify operation and reduce cost of a device and also easily produce a tapered composite material for preparing a cylindrical molding so as to overlap at least at one part, by heating a conductive material by means of an induction heating apparatus and by joining the overlapped part of the sheet.
CONSTITUTION: A composite sheet material for preparing a cylindrical molding is produced by impregnating a fabric or etc. made of a conductive material fiber with a molten thermoplastic synthetic resin and then by drying it. A rolling sheet material with an equivalent width to the length of a cylindrical material to be produced is prepared in order to roll the sheet cylindrically. The delivered sheet material is rolled once or more than twice from a rectangular direction against a mandrel axis on the mandrel perimeter and partially overlapped at the rolling starting edge and the finishing edge of the sheet material. A tapered cylindrical material can be easily made if a taper-shaped mandrel is used. A high-frequency induction heating apparatus is recommended to use as an inductive heating apparatus.
OKUSUE KAZUO
TABUCHI KEIJI
YOSHIMOTO KAZUAKI
| JPS57148619A | 1982-09-14 | |||
| JPS55109649A | 1980-08-23 | |||
| JPS57135123A | 1982-08-20 |