Treatment tool

1. A treatment tool comprising:

an elongated member;

an end effector supported at a distal end of the elongated member so as to be rotatable about a longitudinal axis of the elongated member;

a twisting wire, a first end of the twisting wire being connected to the end effector, a second end of the twisting wire extending toward a proximal end side of the elongated member through an inside of the elongated member;

a handle disposed at the proximal end side of the elongated member, the handle being fixed to the elongated member;

a movable body movable relative to the handle between:

a first state where a first surface of the movable body contacts a second surface of the handle to restrict rotation of the end effector about the longitudinal axis of the elongated member; and

a second state where the first surface is moved away from contact with the second surface to permit rotation of the end effector about the longitudinal axis of the elongated member; and

a converting mechanism configured to couple the movable body with the twisting wire such that:

when the movable body is moved into the second state, the movable body applies a tensile force to the twisting wire; and

when the movable body is released from the second state, the movable body is urged in a direction toward a distal end side of the elongated member by at least a restoring force of the twisting wire to move the movable body into the first state;

wherein the movable body is a dial movable in rotation such that the rotation of the dial results in moving the dial in a longitudinal axis direction of the elongated member, and the converting mechanism comprises a portion of the twisting wire having a male thread, and the dial having a female thread matingly engaged with the male thread.

2. The treatment tool according to claim 1 , wherein the first surface is configured to prevent the rotation of the dial by a friction force.

3. The treatment tool according to claim 1 , wherein the movable body is configured to be passively urged toward the distal end side of the elongated member by the restoring force of the twisting wire when the movable body is not operated by the operator.

4. The treatment tool according to claim 1 , wherein the twisting wire is configured to rotate around the longitudinal axis of the elongated member to apply the tensile force and to rotate the end effector around the longitudinal axis of the elongated member.

5. The treatment tool according to claim 1 , wherein a coefficient of friction between the first and second surfaces is greater than a coefficient of friction between the first surface and surfaces of the handle other than the second surface.

6. The treatment tool according to claim 1 , further comprising a biasing spring for biasing the first surface towards the second surface.

7. A treatment tool comprising:

a tube having a distal end configured to rotatably support an end effector;

a twisting wire disposed along a longitudinal axis of the tube, the twisting wire having a distal end and a proximal end, the end effector being connected to the distal end of the twisting wire; and

at least one wire movable in a longitudinal direction to actuate the end effector, the at least one wire actuating the end effector separately from rotation of the twisting wire to rotate the treatment tool,

a handle disposed at a proximal end side of the tube, and

a dial disposed at the handle and having a locked position and an unlocked position, the dial being configured to rotate around the longitudinal axis of the tube and to move along a longitudinal axis direction upon rotation of the dial,

wherein the handle includes a contact surface configured to contact with a distal end surface of the dial to prevent the rotation of the dial,

in the unlocked position, the distal end surface of the dial moves proximally from the contact surface to apply a tensile force to the twisting wire,

in the locked position, the distal end surface of the dial contacts with the contact surface due to at least a restoring force of the twisting wire;

a converting mechanism comprising: a male thread disposed on the tube and fixed to a portion of the twisting wire, the male thread being disposed along the longitudinal axis direction of the tube; and a female thread disposed on the dial and configured to matingly engage with the male thread, the female thread being disposed along the longitudinal axis of the tube; and the dial is movable in rotation such that the rotation of the dial results in moving the dial in the longitudinal axis direction of the tube.

8. The treatment tool according to claim 7 , wherein a coefficient of friction between the contact surface and the distal end surface is greater than a coefficient of friction between the distal end surface and surfaces of the handle other than the contact surface.

9. The treatment tool according to claim 7 , further comprising a biasing spring for biasing the dial towards the contact surface.

10. A treatment tool comprising:

an elongated member;

an end effector supported at a distal end of the elongated member so as to be rotatable about a longitudinal axis of the elongated member;

a twisting wire, a first end of the twisting wire being connected to the end effector, a second end of the twisting wire extending toward a proximal end side of the elongated member through an inside of the elongated member;

a handle disposed at the proximal end side of the elongated member, the handle being fixed to the elongated member;

a dial rotatably movable relative to the handle between:

a first state where a first surface of the dial contacts a second surface of the handle to restrict rotation of the end effector about the longitudinal axis of the elongated member; and

a second state where the first surface is moved away from contact with the second surface to permit rotation of the end effector about the longitudinal axis of the elongated member; and

a converting mechanism configured to couple the dial with the twisting wire such that:

when the dial is rotated to move into the second state, the dial applies a tensile force to the twisting wire;

when the dial is released from the second state, the dial is urged to move in translation in a longitudinal axis direction toward a distal end side of the elongated member by at least a restoring force of the twisting wire to move dial into the first state;

wherein the converting mechanism comprises:

a portion of the twisting wire having a male thread, and the dial having a female thread matingly engaged with the male thread; and

the dial is movable in rotation such that the rotation of the dial results in moving the dial in the longitudinal axis direction of the elongated member.

11. The treatment tool according to claim 10 , wherein the first surface is configured to prevent the rotation of the dial by a friction force.

12. The treatment tool according to claim 11 , wherein the friction force disappears by moving the dial along the longitudinal axis direction toward the proximal end side of the elongated member such that the second surface is separated from the first surface.

13. The treatment tool according to claim 10 , wherein the dial is configured to be urged toward the distal end side of the elongated member by the restoring force of the twisting wire passively when the dial is not operated by the operator.

14. The treatment tool according to claim 10 , wherein the twisting wire is configured to rotate around the longitudinal axis of the elongated member to apply the tensile force and to rotate the end effector around the longitudinal axis of the elongated member.

15. The treatment tool according to claim 10 , wherein a coefficient of friction between the first and second surfaces is greater than a coefficient of friction between the first surface and surfaces of the handle other than the second surface.

16. The treatment tool according to claim 10 , further comprising a biasing spring for biasing the first surface towards the second surface.