Servo-controlled rotating clamping device for use with a friction stir spot welding apparatus

A friction stir spot welding apparatus comprising:

• a rotatable welding tool;
• a rotational drive portion coupled to the rotatable welding tool and configured to rotate the rotatable welding tool;
• an annular collar coupled to the rotational drive portion;
• a housing component circumferentially disposed about the rotatable welding tool and both coupled with the annular collar and selectively rotatable relative to the annular collar;
• a pressure foot being at least partially located in the housing component and having a discontinuous contact surface for contacting a work piece and a central opening for accommodating the rotatable welding tool, the discontinuous contact surface having at least a first and second contact surface that are respectively disposed on substantially opposing sides of the central opening;
• and
• a motor coupled directly to the housing component via a gear, the motor configured to rotate the housing component about an axis of the rotatable welding tool and with respect to the annular collar, wherein the rotation of the housing component is separate from the rotation of the rotatable welding tool.

A friction stir spot welding apparatus comprising:

• a rotatable welding tool;
• a rotational drive portion coupled to the rotatable welding tool and configured to rotate the rotatable welding tool;
• a support feature and a plunge portion, the plunge portion configured to drive the rotatable welding tool toward the support feature along a depth direction;
• an annular collar coupled to the rotational drive portion;
• a housing component circumferentially disposed about the rotatable welding tool and both coupled with the annular collar and selectively rotatable relative to the annular collar;
• a pressure foot being at least partially located in the housing component and having a discontinuous contact surface for contacting a work piece and a central opening for accommodating the rotatable welding tool, the discontinuous contact surface having at least a first and second contact surface that are respectively disposed on substantially opposing sides of the central opening, the pressure foot being rotationally stationary relative to the housing component;
• a motor coupled directly to the housing component via a gear, the motor configured to rotate the housing component about an axis of the welding tool and with respect to the annular collar, wherein the rotation of the housing component is separate from the rotation of the rotatable welding tool;
• and
• a processor configured to controllably drive the motor to rotate the housing component.