Bending operation apparatus for endoscope

1. A bending operation apparatus for an endoscope, comprising:

a rotation shaft;

a bending operation knob that is rotatable with the rotation shaft, and performs a bending operation of a bending portion of an endoscope;

a fixed shaft that is provided on a same axis as the rotation shaft in an axial direction of the rotation shaft, and is irrotational with respect to the rotation shaft;

a fixed disk that includes a first surface and a second surface, and rotates with rotation of the bending operation knob;

two movable disks including a first movable disk provided at a side of the first surface of the fixed disk, and a second movable disk provided at a side of the second surface of the fixed disk;

a moving member that is located on a same axis in the axial direction as the two movable disks, and moves, the first movable disk or the second movable disk to a first position where the two movable disks are separated by a first space by rotation of the moving member, and a second position where the two movable disks are separated by a second space that is shorter than the first space and at which the two movable disks sandwich the fixed disk by respectively abutting on the fixed disk;

a resistance giving member that is fixed to an outer periphery of the fixed shaft, is provided in an inner side of the moving member, and gives a resistance force to rotation of the moving member; and

a fixing operation member that performs a rotational operation of the moving member,

wherein the resistance giving member has a rocking portion that fixes a rotation position of the moving member in the second position of the movable disk by abutting onto an inner circumferential face of a protruding portion provided at the moving member that moves with the rotation of the moving member, with an urging force, and is rockable in a diameter direction of the moving member.

2. The bending operation apparatus for an endoscope according to claim 1 ,

wherein the rocking portion is configured by an elastic member that is rockable in the diameter direction.

3. The bending operation apparatus for an endoscope according to claim 1 ,

wherein the moving member is a ring-shaped member that rotates with a center axis of the rotation shaft and the fixed shaft as a center by the fixing operation member being rotationally operated.

4. The bending operation apparatus for an endoscope according to claim 3 ,

wherein slits that penetrate in the axial direction are respectively formed in the two movable disks, and

the moving member is a cam member that has the protruding portion that penetrates through the respective slits in the axial direction, the protruding portion being movable in a rotational direction of the rotation shaft in the respective slits, is rotatable in the rotational direction separately from the rotation of the rotation shaft, and causes the two movable disks to move to the second position from the first position by a cam groove formed in the protruding portion, with rotation in one direction.

5. The bending operation apparatus for an endoscope according to claim 4 ,

wherein the rocking portion fixes a rotation position of the cam member in the second position of the movable disk by abutting onto an inner circumferential face of the protruding portion of the cam member that moves with the rotation in the one direction of the cam member, with an urging force.

6. The bending operation apparatus for an endoscope according to claim 5 ,

wherein the protruding portion has a transverse site along the rotational direction, and

the rocking portion abuts on an inner circumferential face of the transverse site that moves with the rotation in the one direction of the cam member.

7. The bending operation apparatus for an endoscope according to claim 4 ,

wherein the protruding portion has a transverse site along the rotational direction, and

the rocking portion is formed to be elongated along the rotational direction to face the transverse site.

8. The bending operation apparatus for an endoscope according to claim 7 ,

wherein a convex portion is formed at the rocking portion, and a step portion is formed at the inner circumferential face of the transverse site, and

the convex portion is fitted in the step portion in the second position so as to fix the rotation position of the cam member in the second position.

9. The bending operation apparatus for an endoscope according to claim 8 ,

wherein two of the convex portions are formed to be separated in the rotational direction with respect to the rocking portion.

10. The bending operation apparatus for an endoscope according to claim 9 ,

wherein out of the two convex portions, by the convex portion that is fitted in the step portion of the transverse site later, with the rotation in the one direction of the cam member, the rotation position of the cam member is fixed in the second position.