Patent ID: 7159307

Claim:
An electrically operated chucking apparatus comprising: an electrically operated chuck comprising at least two movable members movable toward and away from each other, and at least two drive devices which include respective electrically operated actuators operable to move said at least two movable members, respectively, toward and away from each other; and a control device operable to control said at least two drive devices, and wherein said control device includes: a drive control portion operable to control said at least two drive devices such that each of at least one of an actual position and an actual speed of movement of each of said at least two movable members changes toward a predetermined target value; and a load detecting portion operable to detect a load acting on said at least two movable members during operation of said drive control portion to control said at least two drive devices, said drive control portion commanding said at least two drive devices to terminate movements of said at least two movable members when said load detected by said load detecting portion has increased to a predetermined threshold.