| 摘要 |
The method allows, in a completely automatic way, to form the enveloppes of size of the article without leaving space between the welding line and the article. The steps are provided of: in a feeding direction arranging at least a web (30) of continuous film that can be welded thermoplastically according to two continuous wings overlapping each other in order to present a longitudinal closed continuous line. The folded web (38) has a front closed end transversally in a previous step. Thermoplastic cutting and welding means are provided (52) transversal to the web. After opening a part from each other the wings opposite to the continuous longitudinal closed edge (33) an article (10) is inserted to be packaged that is arranged along the web between the thermoplastic cutting/welding means (52) and the front closed end (38). Then, at the level of the thermoplastic cutting/welding means (52), there is the transversal pinching (53) of the folded web by means of a transversal gripper (53), leaving the web (30) free of sliding through the gripper. Then, there is the pulling of the web upstream of (45) the transversal gripper and the drawing back of the web that slides through the gripper until a front edge of the article contacts the front closed end. Then, there is a further drawing back step of the web until a rear edge of the article contacts the transversal gripper. Follows the transversal cutting and welding of the web next to the transversal gripper whereby an enveloppe is formed closed at three sides around the article. In this step no elelements are present for supporting the article, against the transversal gripper, thus using the gripper same as blocking means. Finally, the enveloppe is dragged away and further web is fed, the transversal cutting and welding creating a closed front end in the web.
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