Patent ID: 8734695

Claim:
A manufacturing method of an endoscope flexible tube comprising a tubular structure having flexibility; and a shell layer on an outer peripheral surface of the tubular structure, the method comprising: continuously molding the shell layer including a rigid resin and a soft resin on outer surfaces of a plurality of tubular structures having flexibility and outer surfaces of connecting members while the tubular structures are connected by the connecting members and conveyed in a connected state; wherein the shell layer has a two-layer structure including a rigid resin layer of the rigid resin and a soft resin layer of the soft resin, wherein the two-layer structure is maintained over the entire flexible tube in its length direction, wherein a thickness ratio of the soft resin layer and the rigid resin layer falls within a range of 1:9 to 9:1, wherein each of said plurality of tubular structures having flexibility comprises a first coupling portion at its rear end and a second coupling portion at its distal end, wherein said plurality of tubular structures are connected while the first coupling portion of one of the tubular structures is connected to the second coupling portion of next one of the tubular structures via one of the connecting members, wherein the thickness ratio of the soft resin layer and the rigid resin layer covering the one of the connecting members at a portion adjacent to the first coupling portion of the one of the tubular structures corresponds to the thickness ratio of the soft resin layer and the rigid resin layer covering the one of the tubular structures at the first coupling portion of the one of the tubular structures, and wherein the thickness ratio of the soft resin layer and the rigid resin layer covering the one of the connecting members at a portion adjacent to the second coupling portion of the next one of the tubular structures corresponds to the thickness ratio of the soft resin layer and the rigid resin layer covering the next one of the tubular structures at the second coupling portion of the next one of the tubular structures.