Patent Number: 
Section: claims

1. A clamper comprising:a clamp mechanism which inserts an insertion portion into a tube member as a subject workpiece and clamps the tube member; anda lifting and lowering mechanism which lifts and lowers the clamp mechanism in an insertion direction of the insertion portion, wherein the clamp mechanism comprises:a clamp body which includes the insertion portion at a distal end thereof;a cotter which protrudes from the insertion portion so as to come into friction-contact with the tube member and is disposed so as to be movable in a reciprocating manner in the insertion direction of the insertion portion;a piston rod which presses the cotter so that the cotter protrudes from the insertion portion when being pulled toward the opposite side to the insertion direction of the insertion portion; anda rod cylinder which is unitarily formed on a rear end portion of the clamp body and pulls the piston rod,wherein the lifting and lowering mechanism comprises a lifting and lowering cylinder which is fixed to a wing of a base and inside which the clamp body is disposed such that the clamp body is movable with respect to the lifting and lowering cylinder in the insertion direction,wherein the rod cylinder is disposed outside the lifting and lowering cylinder, andwherein the piston rod is disposed to penetrate the rod cylinder, is movable with respect to the rod cylinder in the insertion direction, and includes a piston portion which is disposed inside the rod cylinder to move the piston rod in the insertion direction by using fluid pressure. 2. The clamper according to claim 1, further comprising: a pressurizing device which is connected through a tube to a fluid chamber that pulls the piston rod by the pressurization of a working fluid of the rod cylinder and pressurizes the working fluid of the fluid chamber; a check valve which is disposed on the tube; and a release valve which discharges the working fluid of the fluid chamber. 3. The clamper according to claim 1, wherein the clamp mechanism includes a cotter diameter decreasing structure which decreases the diameter of the cotter. 4. The clamper according to claim 3, wherein the cotter diameter decreasing structure includes a tapered surface which is formed on the cotter and an elastic member which biases the tapered surface to the clamp body and decreases the diameter of the cotter by sliding the cotter along the tapered surface by the biasing force from the elastic member. 5. The clamper according to claim 3, wherein the cotter diameter decreasing structure includes an annular elastic member which is fitted to the outer periphery of the cotter. 6. An in-channel-head operation device comprising: the clamper according to claim 1.