Patent ID: 7367434

Claim:
An electric power clamping apparatus, which comprises: a clamping arm for clamping a workpiece, an electric motor as a drive source of the clamping arm, a reduction mechanism for reducing a rotation of the electric motor by a plurality of gears, a link mechanism for transmitting an output of the reduction mechanism to the clamping arm, and a manual operation mechanism for manually operating the clamping arm, wherein the manual operation mechanism has an operation shaft provided for manually operating rotatably and movably back and forth by an external tool and a small gear mounted on the operation shaft into a body of the apparatus and is constructed so as to make the clamping arm operate through the reduction mechanism and the link mechanism by rotating the operation shaft in a state to make said small gear mesh with one of the gears of the reduction mechanism by making the operation shaft advance so as to move the operation shaft back, when a manual operation is not performed, and to separate the small gear from one of the gears of the reduction mechanism, and wherein a mechanism for moving a release lever and making a brake mechanism be inoperative connects with the operation shaft and the release lever in the brake mechanism attached to the drive system of the electric motor when the operation shaft is manually operated and said small gear mounted on the operation shaft meshes with one of the gears of the reduction mechanism.