Manipulator

A manipulator comprising:

• an insertion portion configured to be inserted into a body;
• and
• an energy treatment mechanism provided at a distal end of the insertion portion, wherein the energy treatment mechanism comprises:
• a first gripping piece;
• a second gripping piece supported by the first gripping piece so as to pivot about a pivot axis perpendicular to a longitudinal axis of the insertion portion;
• and
• an energy applying part configured to apply energy to body tissue gripped by the first gripping piece and the second gripping piece,
• the insertion portion comprises:
• an energy transfer part configured to transfer energy to the energy applying part;
• and
• a force amplifying mechanism configured to amplify a gripping force of the first gripping piece and the second gripping piece,
• the force amplifying mechanism comprises:
• a pulling pulley supported by the second gripping piece so as to rotate about a pulling rotational axis parallel to the pivot axis, the pulling rotational axis being disposed to be offset proximally from the pivot axis;
• an adjustment pulley supported by the insertion portion so as to rotate about an adjustment rotational axis parallel to the pulling rotational axis, the adjustment rotational axis being disposed to be offset proximally from the pulling rotational axis;
• and
• a wire wound around the pulling pulley and the adjustment pulley, wherein one end of the wire is fixed to the insertion portion, and a pulling force applied to the other end of the wire produces tensions of almost the same magnitudes at both sides of the pulling pulley between which the pulling rotation axis is sandwiched,
• wherein the pulling pulley is disposed at a position so that a resultant force of the tensions acting on the pulling rotational axis produces a rotational moment that cause the second gripping piece to pivot.