Medical treatment tool

1. A medical treatment tool comprising:

an elongated insertion section;

a grasper supported by a distal end of the insertion section so as to be openable and closable, the grasper including a pair of grasping pieces, at least one of which is rotatably supported relative to the insertion section;

a generator disposed at a proximal end of the insertion section and generating a force to drive the grasper;

a transmitter transmitting the force generated by the generator to the distal end of the insertion section;

an amplifier amplifying the force transmitted through the transmitter; and

a toggle amplifying and converting the force amplified by the amplifier into a force directed to open or close the grasper,

wherein the toggle includes a pair of links each having a first end and a second end, the first ends being rotatably connected to proximal end portions of the respective grasping pieces, the second ends being rotatably connected to each other and being supported so as to be movable along a movement axis extending in a longitudinal direction of the insertion section; the pair of links have a length larger than a distance between the first end and the movement axis; and each second end is disposed further distally than a corresponding first end in the longitudinal direction of the insertion section,

the transmitter is a wire that transmits a pulling force along the longitudinal direction of the insertion section,

the amplifier includes a movable pulley supported by the wire wrapping around the movable pulley so that the movable pulley is movable in the longitudinal direction of the insertion section, the movable pulley having a rotation shaft directly connected to the second ends of the pair of links and

the wire has a proximal end connected to the generator, has two segments that extend substantially parallel to each other on respective sides of the movable pulley so as to flank the rotation shaft of the movable pulley, and has another end fixed to the insertion section.

2. The medical treatment tool according to claim 1 , wherein the amplifier amplifies the force by reducing a speed at which the transmitter is moved.

3. The medical treatment tool according to claim 1 , wherein the second ends of the pair of links are rotatably connected to each other at the rotation shaft of the movable pulley.

4. The medical treatment tool according to claim 1 , further comprising a fixed pulley attached so as to be rotatable about a shaft fixed to the insertion section,

wherein the wire is wound between the movable pulley and the fixed pulley.