PURPOSE: To make it possible to fabricate several kinds of large size workpieces with the use of devices each having a small movable extent, by setting a jig bed to which a workpiece is fixed, on a shifting device at the entrance of a working area, and by shifting the jig bed with the use of a servo drive device to a working place so that the workpiece is steplessly positioned in a long range with a high degree of accuracy.
CONSTITUTION: At the stage at which a jig bed 10 fixed thereto with a workpiece 11 is conveyed to the entrance of a working area 15 by means of a conveyor device 23, a jig bed receiving setting seat 30 is raised to position the jig bed 10 with respect to a shifting bed 29 in order to receive the jig bed 10. At the stage at which the shifting bed 29 in a shifting device 26 receives the jig bed 10 fixed thereto with the workpiece 11, a servo drive device 31 positions the shifting bed 29 in the working area 15 with a high degree of accuracy, and therefore, a working device 24 carries out a predetermined working operation such as, for example, welding, etc., at the working position of the workpiece 11. Then, after working is carried out in the movable range 25 of the working device 24, the shifting bed 29 is again shifted by the servo drive device 31 and is positioned with a high degree of accuracy so that a working operation is again carried out at the working position of the workpiece 11 by means of the working device 24, and then the workpiece is finished.
SHIBUYA YUTAKA
HATTORI KEISHI
ITO GENJI
HITACHI TECHNO ENG