Patent EP-2647462-A1 (EP)
Inventor: LEMAITRE JEAN-CLAUDE
IPC: B23K11/30
Filed: 2013-04-05
Abstract: The electrode changer comprises an extraction station (12) that is provided to extract used electrodes out of arms of a clamp to be welded and comprises two pads (48, 50) arranged transversely opposite to one another and provided with driving units arranged in parallel translatory movements in opposed directions so that the pads are adapted to receive the electrodes between the pads forcing a rotation engagement between the pads from the clamp arm in a continuous movement to disconnect the electrode from the corresponding arm. The pads present an input. The electrode changer comprises an extraction station (12) that is provided to extract used electrodes out of arms of a clamp to be welded, and comprises two pads (48, 50) arranged transversely opposite to one another and provided with driving units arranged in parallel translatory movements in opposed directions so that the pads are adapted to receive the electrodes between the pads forcing a rotation engagement between the pads from the clamp arm in a continuous movement to disconnect the electrode from the corresponding arm. The pads present an input chamfered at a side opposite from the electrode to be extracted before entering between the pads and by rotating. The two pads are carried by rack shafts, respectively. The shafts are parallel to rack and simultaneously drive in an axial translation with one shaft in a first direction and the other shaft in an opposite direction so that the movement of the pads in the electrode is relative to the arm of the clamp. Toothed racks are trained in translation by the rotation of a pinion carried at an end of a motorized shaft and formed with the pinion, the motorized shaft and the driving unit. The pinion is positioned between the two toothed racks, and presents teeth adapted to cooperate with teeth of each of the toothed racks in a plane containing axes of toothed racks so that a rotation of the pinion simultaneously trains the toothed racks in the opposed directions to force the rotation of the electrode. The extraction station comprises a case (24) in which the pinion and the toothed racks are placed, and a wall provided with borings forming a guidance unit of the shafts with toothed racks carrying the pads, where the shafts passes through the borings so that the pads extend out of the case. The shafts are relocated by a drive of the pinion between a retracted end position and a deployed end position. The shafts are shifted longitudinally so that a complementary shaft is in its retracted end position when the main shaft is in its deployed end position, and the complementary shaft is in its deployed end position when the main shaft is in its retracted end position. An extraction position to insert the electrode to be extracted is defined between the pads when the shafts are in an end position. The case comprises a back wall provided with borings through which the shafts pass and cross the case so that the toothed racks and the pinion are placed inside the case, and the pads extend out of the case. A control unit for the displacement of the shafts extends out of the case contrary to the pads. The pads have a contact surface placed compared to the other pad and of the corresponding arm. The contact surface presents a series of pins adapted to allow a swing drive of the electrode to be extracted without phenomenon of slip between the pads and the electrode. The pins are aligned in series at an angle compared to an axis of motion in translation of the pads. The pads present the chamfered input that prolongs vertically to the contact surface adapted to be in contact with the electrode, and have gone up on the shafts so that the chamfered surface of the pads mounted on the main shaft is placed on the end of the pads turned towards the case while the chamfered surface of the pads mounted on the complementary shaft is placed on the end opposed to the case. The changer further comprises a detecting unit for detecting a presence of the electrode in the extraction position, a filling shift of new electrodes to replace the used electrodes extracted in the extraction station, a lower electrode charger, and an upper electrode charger. The pads are adapted to receive between an upper electrode and a lower electrode in a position reversed at 180[deg] relative a position of the upper electrode. The pads are adapted to move in translation in the opposite rotational directions to force the electrode between the pads so as to separate the electrodes as the lower or upper electrodes. The chargers are carried by a frame (16) of the changer and placed on both sides of the extraction station. The filling shift carries a series of new upper electrodes and a series of new lower electrodes so that the arms of the clamp are tightened on the electrodes for a simultaneous loading of the lower electrode and the upper electrode.