Patent ID: 9392644
Filing Date: 2016-07-12
CPC Classification: B21D,C21D,H05B

Claim Text:
1. A device for electrically heating comprising a pair of clamping units serving as energizing electrodes, wherein the pair of clamping units move away from each other in a separating direction during the electrical heating so as to apply a tension to a workpiece to be heated and clamped by the pair of clamping units, each of the pair of clamping units comprises: an electrode being movable in approaching and separating directions from the workpiece, a fixed table being immovable in a vertical direction with respect to the workpiece, but movable in a longitudinal direction of the workpiece, said vertical direction is perpendicular to the longitudinal direction of the workpiece, and a movable table, movable in both the vertical and longitudinal directions, said workpiece is mounted in a clamped position in the longitudinal direction on said tables, both of said tables face the electrode through the workpiece in the clamped position, the electrode comprises a step portion protruding toward the movable table, the movable table is disposed in the clamping unit in such a manner whereby the movable table is located closer to the corresponding counterpart clamping unit components than the fixed table is, and when the electrode moves in the approaching direction relative to the workpiece, the movable table is pressed by a protruding portion of the electrode through the workpiece and moves relatively to the fixed table, whereby a step is formed therebetween, during clamping of the workpiece by the clamping units when the electrode moves in the approaching direction relative to the workpiece, the movable table is pressed by the protruding portion of the electrode through the workpiece while the workpiece is clamped by the protruding portion of the electrode and the movable table, to thereby form the step between the movable table and the fixed table, the fixed table adding a pressure to an end of the workpiece in a direction opposite to a moving direction of the electrode and the workpiece is bent, whereby a preform including an inclined surface inclined to a plane direction of the workpiece is formed, and the inclined surface is a surface receiving the tension applied by moving the pair of clamping units away from each other in the separating direction.