| 摘要 |
Control device for machines for making welded bags or sacks made from tubular or semi-tubular webs of thermoplastic material, which consists of a feed-roller pair (3) for the web, which pair is driven directly by a motor (4) or via a gearing by a geared motor, and of a welding-jaw pair (7) which provides the web with welded seams, transverse welded seams or transverse welded separating seams and the opening and closing movements of which are derived via a gearing from a second motor (8). A central arithmetic unit (10) controls the motors in such a manner that the motor of the welding-jaw pair is already supplied driving energy while the motor driving the feed-roller pair is still receiving energy for driving the feed-roller pair. After the standstill phase of the motor of the feed-roller pair, the latter is already driven again before the motor of the welding-jaw pair has come to a standstill. In order to make the capacity of the device variable up to maximum capacity, the speed of the feed-roller pair can be changed at will to lengthen or shorten the feed time for a web section corresponding to a bag or a sack length. …<IMAGE>… |
