Patent ID: 8256755

Claim:
A clamp apparatus for converting linear motion output from a driving section into rotary motion and clamping a workpiece through a clamp arm, the clamp apparatus comprising: a body; a driving section connected to the body and having a displacement rod that is displaceable along an axial direction of the body; a clamp arm supported rotatably with respect to the body; a drive force transmission mechanism including a displacement body connected to the displacement rod for displacement along the body, and a link groove extending in an axial direction of the displacement body and through which a spindle that supports an end of the clamp arm is inserted, the drive force transmission mechanism transmitting a drive force from the driving section to the clamp arm, wherein the clamp arm is rotatably displaced by causing displacement of the spindle along the link groove; and a thrust increasing mechanism disposed in the drive force transmission mechanism for increasing a clamping force when the workpiece is retained by the clamp arm, wherein the thrust increasing mechanism is made up from an inclined portion, which is formed in the link groove and extends while being inclined at a predetermined angle with respect to an axis of the displacement body, and further, wherein the spindle engages with the inclined portion at a time of clamping when the workpiece is supported by the clamp arm, and wherein the inclined portion causes gradual rotation of the clamp arm via the spindle in a direction for clamping the workpiece, and wherein the body includes an opening through which the clamp arm is inserted, a cover being installed over the opening and capable of displacement along the axial direction of the body.