| 摘要 |
Shrink film perforating unit for perforating thermoplastic film material, for example of the type used to wrap articles which are then subjected to heat shrinking tunnel treatment to shrink the thermoplastic material tightly around the article yet permit captive hot air to escape via such perforations, such unit being in the form of a rotary heated perforator arrangement including rotor having heatable external contact perforation points, e.g. in the form of a star wheel, and a stator with heating means captively received within an internal axial bore of the rotor for heating the external contact perforation points, with sufficient clearance being provided therebetween to permit unhindered rotation of the rotor about the stator, whereby the stator may be stationarily mounted with respect to the rotor and the rotor rotatably mounted so as to be disposable for location crosswise of the path of travel of a movable web of thermoplastic film material, e.g. maintained under slight tension by coacting conveying rollers, and in selectively spaced relation thereto for permitting the contact perforation points to engage the adjacent surface of the web operatively for heat perforation thereof upon concordant rotation of the rotor and movement of the web.
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