| 摘要 |
<p>A packaging machine comprises means (11) for forming a tube of slideable film (12) arranged around a sequence of products and is provided with a transverse welding station (14) of the tube with a pair of welding bars (15, 16). The welding station (14) comprises a first motor-driven movement unit (18) for moving the bars towards and away from one another in a normal direction to the sliding direction of the tube of film, and a second motor-driven movement unit (19) for moving the first motor-driven movement unit in a direction parallel to the sliding direction of the film. Electronic control means (20, 21, 22) commands the first and second movement unit in a synchronised manner to make the welding bars perform interpolated curves that simulate cam profiles.</p> |
