Patent ID: 8206286

Claim:
A flexible tube for an endoscope, the flexible tube configured to be inserted into a body cavity of a patient, the flexible tube comprising: a flexible tubular portion including a core member and an outer cover which covers an outer periphery of the core member, the flexible tubular portion having a tip end and a base end; a bendable portion provided at the tip end of the flexible tubular portion and including a core member and an outer cover which covers an outer periphery of the core member, the bendable portion having a tip end and a base end; a tightening string securing an end portion of the outer cover of the bendable portion at the base end side thereof and an end portion of the outer cover of the flexible tubular portion at the tip end side thereof, onto the core member of the bendable portion or the core member of the flexible tubular portion, the tightening string comprising a filament assembly formed by bundling a plurality of filaments of a synthetic resin in a rectilinearly arranged condition; and an adhesive for securing the tightening string on the outer cover, wherein, when the outer diameter of each of the filaments is defined as A and the outer diameter of the filament assembly is defined as B, the value B/A is in the range of 2 to 30, wherein the tightening string is applied on an endoscope so that the tightening string forms at least two layers of untwisted filaments, and the adhesive is applied to the tightening string to cover the tightening string so that the adhesive infiltrates between the at least two layers to bond the at least two layers and to affix the tightening string to the outer cover.