Patent ID: 8663090

Claim:
An endoscope cleaning sheath, comprising: a flexible tube body that comprises a hole for an endoscope insertion portion through which an insertion portion having a bending portion included in an endoscope is inserted, a first fluid conduit that supplies a gas, and a second fluid conduit that supplies a liquid, the hole, the first fluid conduit and the second fluid conduit being through-holes that are parallel to a longitudinal axis of the flexible tube body; and a cylindrical distal end nozzle that is provided at a distal end portion of the flexible tube body and that sprays at least one of the gas supplied through the first fluid conduit and the liquid supplied through the second fluid conduit at least at an observation window provided at a distal end portion of the insertion portion of the endoscope; wherein: the flexible tube body comprises a thin-walled region and a thick-walled region that are configured by arranging a central axis of the hole for an endoscope insertion portion to be eccentric in a predetermined direction of an orthogonal axis orthogonal to a central axis of the flexible tube body which is the longitudinal axis of the flexible tube body, the thin-walled region having a first wall thickness and a first cross-sectional area, and the thick-walled region having a second wall thickness and a second cross-sectional area wherein the first wall thickness and the first cross-sectional area are less than the second wall thickness and the second cross-sectional area; the first fluid conduit and the second fluid conduit are provided in the thick-walled region at positions symmetrical with the orthogonal axis therebetween in a direction that is different from a bending direction of the bending portion of the insertion portion that is inserted and disposed in the hole for an endoscope insertion portion; the thick-walled region of a sheath bending portion includes a first communicating hole provided between the first fluid conduit and the second fluid conduit to allow an outside of the flexible tube body to communicate with an inside of the hole, and a second communicating hole radially spaced from the first communicating hole with the first fluid conduit disposed therebetween, and a third communicating hole radially spaced from the first communicating hole with the second fluid conduit disposed therebetween; and the first, second and third communicating holes each comprise a proximally spaced communicating hole and a distally spaced communicating hole in the sheath bending portion of the flexible tube body, wherein a perimeter of the distally spaced communicating hole is greater than a perimeter of the proximally spaced communicating hole for each of the first, second and third communicating holes, wherein a distal portion of the sheath bending portion containing the distally spaced communicating holes exhibits decreased bending resistance with respect to a proximal portion of the sheath bending portion containing the proximally spaced communicating holes.