| 摘要 |
An improved film tube forming shoe includes a brake edge having a configuration which is related to the diameter of the shoe, to the film width, and to the diameter of a product to be wrapped in the tube. The shoe is provided with outwardly directed pressurized fluid ports in the brake edge to provide an air cushion for the film as it is drawn through an acute angle around the brake edge into the shoe. The fluid also cleans the edge and reduces accumulation of foreign matter thereon. To promote accurate film tracking through the shoe, it is rotatable in response to changes in the position of an edge of the film before it enters the shoe. Methods are provided for forming the shoe, and brake edge, without trial and error, for wrapping products of known diameter, and for wrapping articles.
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