Hot shrink packaging of different size articles - using quick change mechanism to change to sheet of different width

摘要

A packaging machine for wrapping articles in shrink foil consists of a path along which the articles are conveyed, a top feed device with feed rool for a top sheet of plastics and a similar, corresp. bottom feed device for a bottom sheet of plastics; these sheets are seal-welded together ahead of each separate article at a transverse gap in the conveyed path and then seal-weleded again behind it as it moves forward, the sheets being simultaneously cut to complete the package; the top and bottom sheet feed devices complete with their rolls are constituted as one single unit which can be removed transversely to one side of the conveying path. Pref., there are two such interchangeable units which can be introduced into the conveying path alternatively for use, so that the one which is not in use is used for changing the rolls. The two units are pref. joined together rigidly on a common travelling trolley running on transverse rails. The two units are pref. spaced apart by a distance equal to the max. width of sheet to be used, and each has its own set of welding jaws similarly spaced apart for operating in the gap. When it is desired to change the rolls of sheet supplied, e.g., to suit packages of different widths, a rapid change is possible simply by sliding the trolley across.