Endoscope apparatus

An endoscope apparatus comprising:

• an insertion portion;
• a bending portion provided at a distal end of the insertion portion;
• an operation portion provided at a proximal end of the insertion portion and configured to perform a bending operation for bending the bending portion;
• a pull member configured to connect the bending portion to the operation portion and configured to be pulled by the bending operation by the operation portion, to thereby bend the bending portion;
• and
• a bent state retention mechanism which retains the bending portion in a desired bent state, the bent state retention mechanism being arranged between the operation portion and the insertion portion;
• wherein the operation portion comprises:
• a joystick which is supported so as to be freely inclinable about a predetermined swinging center and to which the bending operation for bending the bending portion is input;
• and
• a friction member that is fixed to the joystick and on which a partially spherical contact surface is formed, a center of the contact surface being the swinging center;
• and
• wherein the bent state retention mechanism comprises:
• a relay member arranged on and extending in a direction of an axis line including the swinging center, the relay member being movable along the axis line and comprising (i) a stopper portion which is provided at a proximal end of the relay member and which stops motion of the joystick when the stopper portion comes into contact with the friction member, and (ii) a protrusion portion which is provided at a distal end of the relay member and which extends in a direction perpendicular to the axis line;
• a grip member comprising a cylindrical member arranged along the axis line so as to surround the relay member and the pull member, an outer circumferential surface of the grip member being adapted to be gripped by a user, and the grip member being rotatable about the axis line as a rotation center;
• and
• a cam member formed with a guide wall which forms a part of a spiral about the axis line and which engages with the protrusion portion, the cam member being rotatable with respect to the relay member about the axis line as a rotation center in accordance with rotation of the grip member;
• wherein:
• when the grip member is rotated in a first rotational direction about the axis line, the relay member is moved toward the swinging center along the axis line and the stopper portion comes into contact with the friction member;
• and
• when the grip member is rotated in a second rotational direction about the axis line which is opposite to the first rotational direction, the relay member is moved in a direction away from the swinging center along the axis line and the stopper portion is spaced away from the friction member.