Patent ID: 8366090

Claim:
A clamping apparatus configured to be switched between an unclamped condition and a clamped condition, the clamping apparatus comprising; a plug portion, including a housing, projected from a first block in a leading end direction so as to be inserted into a insertion hole opened in a second block, a support surface formed on the housing so as to be brought into contact with a supported surface formed on the second block, a fluid flow hole opened in the support surface, a gap supporting member provided on the first block so as to push the second block in such a direction as to separate the second block from the first block and to form a gap between the supported surface and the support surface, the gap supporting member configured to push the second block via a receiving portion in the leading end direction beyond the support surface when the apparatus is in the unclamped condition to form the gap between the supported surface and the support surface, wherein said receiving portion comes into contact with a portion of a bottom surface of the second block and wherein said portion of the bottom surface of the second block includes a circumferential opening that has a circumference the same as a circumference of an opening end of the insertion hole, and a pull member eliminating the gap by making the second block approach the first block against a pushing force of the gap supporting member in such a condition that an outer peripheral surface of the plug portion is brought into close contact with an inner peripheral surface of the insertion hole in a radial direction.