Patent ID: 9301800
Filing Date: 2016-04-05
CPC Classification: A61B

Claim Text:
1. A treatment tool comprising: a cutting section which is adapted to be endoscopically inserted into a body cavity and performs cutting procedures by transforming high frequency current, the entirety of the cutting section being conductive; a wire connected to the cutting section at a distal end of the wire; a sheath comprising an insulating material, the wire being inserted into the sheath; a main body, a back end of the sheath being connected to the main body; and a slider to which a back end of the wire is fixed and which is disposed to the main body to enable sliding in an axial direction of the sheath, wherein the cutting section has a large diameter part at a distal end of the cutting section and a small diameter part proximal to the large diameter part, the large diameter part having an outer diameter such that the large diameter part is not capable of being accommodated in the sheath when the cutting section is maximally retracted along the axial direction toward the back end of the sheath, wherein the large diameter part includes at least a first portion and a second portion, the first portion at least partially including a circular cross-section formed in a direction orthogonal to a longitudinal axis of the cutting section at a distal end of the small diameter part and the second portion at least partially including a first rounded surface conductively connected to a circumference of the first portion, the second portion being disposed at a distal end of the first portion, wherein a tubular distal member having insulating properties is disposed on a distal end of the sheath, the tubular distal member including an insertion portion that is inserted into the sheath and a tip that is exposed outside the sheath, wherein the tip at least includes a second rounded surface, a radius of curvature of the second rounded surface being larger than that of the first rounded surface, and wherein when the cutting section is maximally retracted along the axial direction toward a proximal end of the sheath, a proximal surface of the second portion contacts with a distal end of the tip such that the large diameter is restricted to not to be accommodated in the sheath, the first rounded surface being more distal than the second rounded surface.