Grasping treatment instrument

Abstract

A grasping treatment instrument includes a sheath extending along a longitudinal axis, a first grasping piece provided at a distal end portion of the sheath, a second grasping piece moving rotationally relative to the sheath, thereby opening and closing relative to the first grasping piece to grasp a living tissue between the second grasping piece and the first grasping piece, a protrusion provided on the second grasping piece and protruding in a direction intersecting with the longitudinal axis and a direction in which the second grasping piece opens and closes, and a recess that engages with the protrusion at the distal end portion of the sheath and has a recessed shape that opens in a direction intersecting with the direction to which the protrusion protrudes.

What is claimed is: 
     
         1 . A grasping treatment instrument comprising:
 a sheath having a longitudinal axis and extending along the longitudinal axis;   a first grasping piece provided at a distal end portion of the sheath:   a second grasping piece attached to the distal end portion of the sheath so as to be rotationally movable relative to the sheath, the second grasping piece moving rotationally relative to the sheath, thereby opening and closing relative to the first grasping piece to grasp a living tissue between the second grasping piece and the first grasping piece;   a protrusion provided on the second grasping piece and protruding in a direction intersecting with the longitudinal axis and intersecting with a direction in which the second grasping piece opens and closes relative to the first grasping piece; and   a recess that engages with the protrusion at the distal end portion of the sheath and has a recessed shape that opens in a direction intersecting with the direction to which the protrusion protrudes and intersecting with the longitudinal axis.   
     
     
         2 . The grasping treatment instrument according to  claim 1 , further comprising:
 a movable member that extends along the longitudinal axis of the sheath, is connected to the second grasping piece at a region different from a region of the protrusion, and is configured to move relative to the sheath, thereby rotationally moving the second grasping piece relative to the sheath,   wherein the second grasping piece is able to open up to a predetermined angle relative to the first grasping piece, and   wherein the recessed shape of the recess opens in a direction intersecting with a straight line passing through the recess and a connecting portion between the movable member and the second grasping piece, in a state where the second grasping piece opens up to the predetermined angle relative to the first grasping piece.   
     
     
         3 . The grasping treatment instrument according to  claim 2 , wherein the recess includes, in a cross section intersecting with the direction to which the protrusion protrudes, a circular arc-shaped curved surface, a first flat surface that extends from one end of the curved surface toward an opening of the recess, and a second flat surface that extends from another end of the curved surface toward the opening and that is set apart from the first flat surface as being advanced toward the opening. 
     
     
         4 . The grasping treatment instrument according to  claim 2 , wherein the protrusion has a first size that is equal to or smaller than a width of the opening of the recess, in a first direction that intersects with the direction to which the protrusion protrudes, and a second size that is larger than the width of the opening, in a direction that intersects with the direction to which the protrusion protrudes and intersects with the first direction, and
 wherein in a state where the second grasping piece opens up to the predetermined angle relative to the first grasping piece, the first direction is in parallel with a width direction of the opening.   
     
     
         5 . The grasping treatment instrument according to  claim 1 , further comprising:
 a movable member that extends along the longitudinal axis of the sheath, is connected to the second grasping piece at a region different from a region of the protrusion, and is configured to move relative to the sheath, thereby rotationally moving the second grasping piece relative to the sheath,   wherein a connecting portion at which the second grasping piece is connected to the movable member is positioned closer to a distal side than an engagement portion at which the protrusion of the sheath engages with the recess of the second grasping piece.   
     
     
         6 . The grasping treatment instrument according to  claim 1 , wherein the protrusion has a circular arc-shaped curved surface in a cross section intersecting with the direction to which the protrusion protrudes. 
     
     
         7 . The grasping treatment instrument according to  claim 6 , wherein in a cross section intersecting with the direction to which the protrusion protrudes, the recess has a circular arc-shaped curved surface, and
 wherein in a state where the second grasping piece is moving rotationally relative to the sheath, and the curved surface of the protrusion is in contact with the curved surface of the recess.   
     
     
         8 . The grasping treatment instrument according to  claim 1 , wherein the recess has a circular arc-shaped curved surface in a cross section intersecting with the direction to which the protrusion protrudes. 
     
     
         9 . The grasping treatment instrument according to  claim 1 , further comprising:
 a movable member that extends along the longitudinal axis of the sheath, is connected to the second grasping piece at a region different than the protrusion, and is configured to move relative to the sheath, thereby rotationally moving the second grasping piece relative to the sheath,   wherein the recess is positioned, relative to the longitudinal axis, on an opposite side of a connecting portion at which the second grasping piece is connected to the movable member.   
     
     
         10 . The grasping treatment instrument according to  claim 1 , further comprising:
 a movable member that extends along the longitudinal axis of the sheath, is connected to the second grasping piece at a region different than the protrusion, and is configured to move relative to the sheath, thereby rotationally moving the second grasping piece relative to the sheath,   wherein the protrusion has a center axis along the direction to which the protrusion protrudes, and   wherein the protrusion includes an inclined surface that faces toward the center axis of the protrusion as the protrusion is advanced to the direction to which the protrusion protrudes, and that faces a direction intersecting with a straight line passing through the protrusion and a connecting portion between the movable member and the second grasping piece.   
     
     
         11 . The grasping treatment instrument according to  claim 1 , further comprising:
 a pressing member provided inside the sheath, forming a U-shape in a cross section perpendicular to the longitudinal axis, and including a bottom surface portion and side surface portions forming side walls provided on both sides of the bottom surface portion.   
     
     
         12 . The grasping treatment instrument according to  claim 11 , wherein the sheath defines a hole penetrating through side surfaces of the sheath in a width direction of the sheath, and
 wherein the pressing member includes a projecting portion that projects from the side surface portions toward the outside in the width direction and is engaged with the hole defined by the sheath.   
     
     
         13 . The grasping treatment instrument according to  claim 1 , further comprising:
 a movable member that extends along the longitudinal axis of the sheath, is connected to the second grasping piece at a region different than the protrusion, and is configured to move relative to the sheath, thereby rotationally moving the second grasping piece relative to the sheath,   wherein the recessed shape of the recess opens in a direction intersecting with a moving direction of the movable member.   
     
     
         14 . A grasping treatment instrument comprising:
 a sheath having a longitudinal axis and extending along the longitudinal axis;   a first grasping piece provided at a distal end portion of the sheath:   a second grasping piece attached to the distal end portion of the sheath so as to be rotationally movable relative to the sheath, the second grasping piece moving rotationally relative to the sheath, thereby opening and closing relative to the first grasping piece to grasp a living tissue between the second grasping piece and the first grasping piece;   a protrusion provided on the second grasping piece and protruding in a direction intersecting with the longitudinal axis and intersecting with a direction in which the second grasping piece opens and closes relative to the first grasping piece; and   a recess that engages with the protrusion at the distal end portion of the sheath and has a recessed shape that opens in a direction intersecting with the direction to which the protrusion protrudes,   wherein the protrusion moves toward an opening of the recess having the recessed shape as the second grasping piece opens relative to the first grasping piece.   
     
     
         15 . The grasping treatment instrument according to  claim 14 , further comprising:
 a movable member that extends along the longitudinal axis of the sheath, is connected to the second grasping piece at a region different from a region of the protrusion, and is configured to move relative to the sheath, thereby rotationally moving the second grasping piece relative to the sheath,   wherein the second grasping piece is able to open up to a predetermined angle relative to the first grasping piece, and   wherein the recessed shape of the recess opens in a direction intersecting with a straight line passing through the recess and a connecting portion between the movable member and the second grasping piece, in a state where the second grasping piece opens up to the predetermined angle relative to the first grasping piece.   
     
     
         16 . The grasping treatment instrument according to  claim 15 , wherein the recess includes, in a cross section intersecting with the direction to which the protrusion protrudes, a circular arc-shaped curved surface, a first flat surface that extends from one end of the curved surface toward an opening of the recess, and a second flat surface that extends from another end of the curved surface toward the opening and that is set apart from the first flat surface as being advanced toward the opening. 
     
     
         17 . The grasping treatment instrument according to  claim 14 , further comprising:
 a movable member that extends along the longitudinal axis of the sheath, is connected to the second grasping piece at a region different from a region of the protrusion, and is configured to move relative to the sheath, thereby rotationally moving the second grasping piece relative to the sheath,   wherein a connecting portion at which the second grasping piece is connected to the movable member is positioned closer to a distal side than an engagement portion at which the protrusion of the sheath engages with the recess of the second grasping piece.   
     
     
         18 . The grasping treatment instrument according to  claim 14 , further comprising:
 a movable member that extends along the longitudinal axis of the sheath, is connected to the second grasping piece at a region different than the protrusion, and is configured to move relative to the sheath, thereby rotationally moving the second grasping piece relative to the sheath,   wherein the recessed shape of the recess opens in a direction intersecting with a moving direction of the movable member.   
     
     
         19 . A manufacturing method of a grasping treatment instrument which comprises a sheath having a longitudinal axis, a first grasping piece provided at a distal end portion of the sheath; a second grasping piece that defines a first hole and grasps a living tissue between the second grasping piece and the first grasping piece, a movable member that extends along the longitudinal axis of the sheath, defines a second hole, and is configured to move relative to the sheath, thereby rotationally moving the second grasping piece relative to the sheath; a protrusion provided on the second grasping piece and protruding in a direction intersecting with the longitudinal axis and intersecting with a direction in which the second grasping piece opens and closes relative to the first grasping piece; and a recess provided at the distal end portion of the sheath and having a recessed shape that opens in a direction intersecting with the direction to which the protrusion protrudes, the manufacturing method comprising:
 inserting the protrusion into the recess in a state where the movable member is placed inside the sheath;   positioning the second hole to fit with the first hole by rotationally moving the second grasping piece relative to the sheath using the protrusion as a fulcrum, and   inserting a connector through the first hole and the second hole in a state where the second hole is positioned to fit with the first hole.