JPS5831287B

• Main Author: SHIMONO SEIICHI
• Format: Patent
• Language: English
• Published: 05.07.1983
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; MAKING GRANULES OR PREFORMS; PERFORMING OPERATIONS; PREPARATION OR PRETREATMENT OF THE MATERIAL TO BESHAPED; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIALCONTAINING PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

PURPOSE:To mold continuously a cylindrical body by extrusion in which the thickness is increased locally and clearly at desired positions by a method wherein the sectional shape of a core bar is expanded or contracted directly during forming, and forming clearances are changed to adjust the thickness of a product. CONSTITUTION:Pressure oil or compressed air is supplied from a pipe 17 into a cylinder 12 via a through hole 16 and the cylinder 12 is pushed backward to compress an elastic body 13 through a cover plate 12a. The elastic body 13 is reduced in length and increased in diameter to contract the forming clearance 14. Resin 18 passes through an arm 9b and a cylindrical body of thickness t0 is molded continuously. When the pressure oil or compressed air in the cyinder 12 is removed through the pipe 17 to release the pressure in the cylinder, the elastic body 13 pushes the cylinder forward and returns to the original shape by its own stability and the frictional force of the resin 18. The molding clearance 14 is expanded and the cylindrical body of tickness t1 is molded continuously.