Patent ID: 8580063
Filing Date: 2013-11-12
Classification: A61B,B29C,B29K,B29L

Abstract:
1. A method for producing an endoscope flexible tube, said method comprising: preparing a flexible tube assembly including a spiral tube formed by spirally winding a metal strip and a cylindrical mesh sleeve, covering the spiral tube, formed by knitting metal wires; covering the flexible tube assembly with an outer coat from one end toward another end of the flexible tube assembly by using an extrusion molding machine, wherein the outer coat comprises a lower layer comprising a thermoplastic polyurethane elastomer and an upper layer comprising a thermoplastic polyester elastomer, and a total thickness of the upper layer and the lower layer is constant; and annealing the covered flexible tube assembly at a temperature in a vicinity of a softening point of a layer with a lower softening point out of the upper layer and the lower layer after the covering the flexible tube assembly with the outer coat, wherein in the covering with the outer coat, a melt viscosity ratio, as thermoplastic polyurethane elastomer/thermoplastic polyester elastomer, with reference to an exit temperature of the extrusion molding machine, between the thermoplastic polyurethane elastomer and the thermoplastic polyester elastomer is set to fall within a range from 1 to 35, and a thickness ratio between the upper layer and the lower layer is gradually varied in such a way that one of the upper layer and the lower layer has a maximum thickness at the one end and the one of the upper layer and the lower layer has a minimum thickness at the another end, and wherein the preparing the flexible tube assembly comprises at least connecting a plurality of sets each comprising the flexible tube assembly and a dummy member in such a way that the flexible tube assemblies and the dummy members are alternately connected with a plurality of joint members.