Device for packaging products with sheets of extensible plastic material

摘要

The packaging device comprises a plurality of jaws (9) symmetrically mounted on a pair of endless chains (1) which are rotatable at adjacent vertical levels, and are operated by opening cams (18) and closing cams (19) for the gripping or the release of the web (10) of extensible plastic material which is drawn along horizontally. The lifting element (30) permits the carrying of a tray (31) containing the products to be packaged from below and between the sides, to achieve contact with the extensible sheet of the web (10) which is stretched by making use of the properties of extensibility. Through the slit (21) a metal wire, which is electrically heated, permits the cutting of the extensible material into sheets of length which is variable according to choice. The completion of the wrapping is then effected by known folders. The present device, which is used especially in the packaging of food products of all types and sizes intended for supermarkets, permits the production of packs which are faultless as regards adhesion and without the formation of folds, in contrast to the packs of the prior art which, being based on a transverse drawing action and not on a longitudinal drawing action on the web, cause a transverse shrinkage thereof with the consequent formation of folds and loss of quality of the pack. <IMAGE>