| 摘要 |
Mounted adjacent and in alignment with the workpiece supporting portion of a workpiece-shape-altering machine, such as the lower die of a stamping press, is a laser beam source, the outgoing beam from which passes through a beam splitter which divides the entering beam. One of the two emergent beams from the beam-splitter is a workpiece position-inspecting beam which passes in a grazing direction across one portion of the top of a workpiece resting upon the lower die for subsequent stamping by the upper die of the press. This beam continues onward to a mirror which reflects it in a grazing direction back across another portion of the top of the workpiece to a workpiece position detector. The other emergent beam from the beam splitter is a workpiece presence-inspecting beam which is obstructed by the workpiece, if present on the lower die, so that it does not reach the workpiece presence detector therebeyond. If, however, the workpiece has not been delivered to the lower die or, if delivered and worked upon, has adhered to and has been carried upward with the upper die, the workpiece presence detector immediately transmits the absence of the workpiece from the lower die to the electrical control system of the press, which prevents the operation of the press until a workpiece is properly supplied to and positioned upon the lower die. On the other hand, even if the workpiece is in position on the lower die but is improperly positioned, such as being tilted, so that it obstructs the workpiece position-inspecting beam with the result that the beam does not reach the workpiece detector, the improper position of the workpiece is transmitted to the electrical press control system, which thereupon prevents actuation of the press until the workpiece has been properly repositioned upon the lower die by the operator.
|
