| 摘要 |
<p>A machine for perforating high density polyethylene film comprising a feed roller, cooperating male and female rollers between which the film passes for perforation and a take-up roller for receiving the perforated film material. A plurality of blade members are housed within the male roller and under the influence of adjustable indexing means are adapted for reciprocal motion relative to the surface of the male roller. In the vicinity of the female roller preselected ones of the blade members are caused to project from the surface of the male roller and to enter a complementary recess in the female roller to perforate the film material as it passes between the male and female rollers. The longitudinal distance between the perforations on the film is determined by the selection of blade members caused to project from the male roller during each revolution of the male roller.</p> |
