Processing method and bending using the core material and core material for bending plastic tubes

摘要

PURPOSE: To facilitate pressing in a mold when a plastic tube is molded, to prevent the flatness of the tube and to draw a core material easily from the tube by constituting a core material body by laminating flexible sheet metals in an approximately circular cross section while forming a cavity section an installing a tube, which is composed of an elastic body and into which a fluid can be injected, in the cavity section. ;CONSTITUTION: In the bending method of a plastic tube 2 using a core material 1, the pressure of a tube 15 mounted to the cavity section 111 of a core material body 11 pushes wide the sheet metals 1A-1L of the body 11 in the direction of laminating and works in the direction of adhesion to the internal surface of the tube 2 when the tube 15 is expanded and contact- bonded with the wall surface of the cavity section 111. Consequently, the tube 2 can be bent and molder under the state in which the body 11 and the tube 2 are fast stuck sufficiently. As a result, the cross section of the body 11 can be held in a true circle in an approximately original shape, and the generation of creases and white color on the surface of the tube 2 can also be prevented. Since the tube 15 is shrunk and the core material 1 is drawn out of the bent and molded tube 2, frictional resistance between the core material 1 and the tube 2 is lowered only by a section, in which the bending reaction of the body 11 is reduced, thus allowing drawing by force smaller than conventional devices.;COPYRIGHT: (C)1993,JPO&Japio