Endoscope bending operation mechanism and endoscope

1 . An endoscope bending operation mechanism, comprising:

a bending operation controller;

a pulley unit including a pulley supported for rotation by a pulley case, the pulley configured to move by an operation force from the bending operation controller;

a wire having a proximal end and a distal end, wherein the proximal end of the wire is connected to the pulley and the distal end of the wire is connected to a bending portion of an endoscope insertion section; and

a movement limiter unit including a limit structure and a stopper structure,

wherein the stopper structure and the limit structure are movable relative to each other,

wherein an amount of relative rotation between the pulley and the pulley case is restricted by the stopper structure contacting the limit structure,

wherein either (i) the limit structure is attachable to and detachable from the pulley case and the pulley includes the stopper structure or (ii) the limit structure is attachable to and detachable from the pulley and the pulley case includes the stopper structure,

wherein the pulley case includes a mounting section including three or more grooves,

wherein the three or more grooves are arranged in an arc around a center of rotation of the pulley and each of the three or more grooves are oriented radially from the center of rotation of the pulley,

wherein the three or more grooves are configured for selectively mounting the limit structure, and

wherein the limit structure includes two stoppers configured to be mounted in two of the three or more grooves.

2 . The endoscope bending operation mechanism according to claim 1 , wherein, when the limit structure is mounted in the mounting section, the limit structure includes a part that protrudes from the pulley case to form an abutting portion of the limit structure that is contacted by the stopper structure and by which the amount of relative rotation between the pulley and the pulley case is restricted.

3 . The endoscope bending operation mechanism according to claim 1 , wherein the two stoppers are a first stopper configured to be inserted into and protrude from a first groove of the two of the three or more grooves and a second stopper configured to be inserted into and protrude from a second groove of the two of the three or more grooves, and

wherein, when the limit structure is mounted in the mounting section with the first stopper inserted into and protruding from the first groove and the second stopper inserted into and protruding from the second groove, an angular separation between the first stopper and the second stopper defines the amount of relative rotation between the pulley and the pulley case.

4 . The endoscope bending operation mechanism according to claim 1 , wherein the pulley case includes a first pulley housing body and a second pulley housing body that faces the first pulley housing body, wherein, in the pulley case, a first side of the first pulley housing body is oriented toward a first side of the second pulley housing body with the pulley located therebetween,

wherein the endoscope bending operation mechanism further comprises:

a second bending operation controller; and

a second pulley configured to move by a second operation force from the second bending operation controller, and

wherein the second pulley is located on a second side of the first pulley housing body.

5 . The endoscope bending operation mechanism according to claim 4 , wherein the endoscope bending operation mechanism further comprises a second wire having a proximal end and a distal end, and

wherein the proximal end of the second wire is connected to the second pulley and the distal end of the second wire is coupled to the bending portion.

6 . The endoscope bending operation mechanism according to claim 5 , wherein the pulley case includes a third pulley housing body,

wherein, in the pulley case, a first side of the third pulley housing body is oriented toward the second side of the first pulley housing body with the second pulley located therebetween,

wherein the endoscope bending operation mechanism further comprises:

a second movement limiter unit including a second limit structure and a second stopper structure,

wherein the second stopper structure and the second limit structure are movable relative to each other,

wherein an amount of relative rotation between the second pulley and the pulley case is restricted by the second stopper structure contacting the second limit structure, and

wherein either (i) the second limit structure is attachable to and detachable from the first pulley housing body or the third pulley housing body and the second pulley includes the second stopper structure or (ii) the second limit structure is attachable to and detachable from the second pulley and the first pulley housing body or the third pulley housing body includes the second stopper structure.

7 . The endoscope bending operation mechanism according to claim 6 , wherein the third pulley housing body mates to the second pulley housing body.

8 . An endoscope, comprising

an operation section disposed proximally relative to the endoscope insertion section, the operation section including the endoscope bending operation mechanism according to claim 1 , the endoscope bending operation mechanism configured to operate the bending portion.

9 . The endoscope according to claim 8 , wherein the endoscope insertion section extends in a longitudinal direction, and

wherein the pulley case includes a guide portion configured to guide the wire to move in the longitudinal direction.

10 . An endoscope bending operation mechanism, comprising:

a bending operation controller;

a pulley configured to move by an operation force from the bending operation controller;

a pulley case supporting the pulley for rotation;

a wire having a proximal end and a distal end, wherein the proximal end of the wire is connected to the pulley and the distal end of the wire is connected to a bending portion of an insertion section of an endoscope that is configured to insert into a subject; and

two limit structures,

wherein the pulley case includes three or more slit-shaped recessed grooves, two of the three or more slit-shaped recessed grooves are configured to mount the two limit structures, and

wherein the three or more slit-shaped recessed grooves are arranged in an arc around a center of rotation of the pulley and each of the three or more slit-shaped recessed grooves are oriented radially from the center of rotation of the pulley.

11 . The endoscope bending operation mechanism according to claim 10 , wherein the pulley includes a stopper structure, an amount of relative rotation between the pulley and the pulley case is restricted by the stopper structure contacting two limit structures.

12 . The endoscope bending operation mechanism according to claim 11 , wherein, when the two limit structures are mounted in the two of the three or more slit-shaped recessed grooves, the two limit structures include a part that protrudes from the pulley case to abut on the stopper structure.

13 . The endoscope according to claim 8 , wherein, when the limit structure is mounted in the mounting section, the limit structure includes a part that protrudes from the pulley case to form an abutting portion of the limit structure that is contacted by the stopper structure and by which the amount of relative rotation between the pulley and the pulley case is restricted.

14 . The endoscope according to claim 10 , wherein the two limit structures are a flat plate.