Patent ID: 7075966

Claim:
In combination, a consumable electrode and an electrode column for an electric arc furnace, said electrode being movable downwardly along a longitudinal axis defined by the electrode, said electrode column comprising: (a) a power clamp through which electrical power is delivered to the electrode, the power clamp comprising an annular contact element through which the electrode extends and which is in contact with the electrode, the power clamp exerting a first clamping force on the electrode through said annular contact element; (b) a first slipping sleeve having a hollow cylindrical interior through which the electrode extends and exerting a second clamping force on the electrode, the first slipping sleeve being axially movable and being movable relative to the electrode and the power clamp; and (c) a second slipping sleeve having a hollow cylindrical interior through which the electrode extends and exerting a third clamping force on the electrode, the second slipping sleeve being axially movable and being movable relative to the electrode, the power clamp and the first slipping sleeve; wherein the power clamp and the slipping sleeves together support the electrode and wherein the first, second and third clamping forces are selected such that simultaneous downward axial movement of the first and second slipping sleeves, while maintaining the first, second and third clamping forces, results in downward axial movement of the electrode relative to the power clamp, and such that upward or downward axial movement of only one of the first and second slipping sleeves, while maintaining the first, second and third clamping forces, results in axial movement of said one of the first and second slipping sleeve relative to the electrode.