Wire driver for wire line and endoscope

An endoscope comprising:

• an elongated tube for entry in a body cavity for imaging of an object;
• a wire line, contained in said elongated tube, for moving in an axial direction back and forth;
• a movable part, coupled with a distal end of said wire line, caused to shift between first and second positions by said wire line;
• an externally operable device, disposed at a proximal end of said wire line, for moving said wire line in said axial direction;
• a drive lever for pivotally moving upon operation of said externally operable device;
• and
• a cam mechanism, connected between said externally operable device and said wire line, configured to shift said movable part, during the pivotal movement of said drive lever by the operation of said externally operable device, at a first shift amount between said first position and an intermediate position being defined between said first and second positions, and shifting said movable part at a second shift amount smaller than said first shift amount between said intermediate position and said second position,
• the first shift amount and the second shift amount being defined for a unit operation amount of the externally operable device,
• the endoscope further comprising:
• a link portion for transmitting movement of said externally operable device to said proximal end of said wire line;
• and
• a coupling shaft for coupling said externally operable device to said link portion, said cam mechanism including:
• a cam plate;
• and
• a cam groove for receiving said coupling shaft, said cam groove being formed in said cam plate,
• wherein said cam groove includes:
• a first groove portion for shifting said coupling shaft, said first groove portion having an arcuate shape whose center is substantially coincident with a rotational center of said drive lever;
• and
• a second groove portion for shifting said coupling shaft at a smaller shift amount than a shift amount of said coupling shaft in said first groove portion, said second groove portion being disposed to continue from said first groove portion and directed to come nearer to said rotational center of said driver lever from said first groove portion.