METHOD OF POSITIONING SHEET ELEMENTS IN THE INTRODUCTION STATION OF A PROCESSING MACHINE AND A SYSTEM FOR PERFORMING THE METHOD

摘要

A B S T R A C TA method of positioning sheet elements (5) in theintroduction station of a processing machine comprisinga transport system consisting of one or more bars (10)of grippers (12) for driving the sheet element (5) tosubsequent stations, comprises, starting from a shelf(14) in a rear starting position, engaging means (16,22) for fixing a sheet element (5) on the shelf (14),then controlling actuators (40, 50, 60) to advance theshelf (14) forward and if necessary sideways and/oraskew depending on the readings of the positioning co-ordinates of the sheet element (5) by opto-electronicmeans (72, 74, 76), said readings being effected duringthe advance of the shelf (14) so as to feed and finallystop the leading edge of the sheet element (5) in thegrippers (12) of the transport system in apredetermined position, releasing the fixing means (16,22), and then returning the shelf (14) to the rearstarting position. The system for performing themethod comprises a shelf (14) provided with means (16,22) for temporarily fixing the sheet element (5),having a notched leading edge (17) complementary to thegrippers (12) of the drive bar (10) driven by actuators(40, 50, 60), opto-electronic means reading the frontand/or side edge and/or a distinctive sign of aprevious treatment of the sheet element disposedslightly forwardly of the starting position of theshelf, and electronic control means for controlling theactuators of the shelf (14) in dependence on themachine cycle and the results of the readings of thepositioning co-ordinates of the sheet element (5) bythe opto-electronic means.(Fig. 1)