[54] SCREEN FOR PRODUCING A PERFORATED FILM
[75] Inventor: Gregory M. Rieker, Clinton, Ind.
[73] Assignee: Tredegar Industries, Inc., Richmond, Va.
[ * ] Notice: The term of this patent shall not extend beyond the expiration date of Pat. No. 5.562.932.
[21] Appl. No.: 663,614
[22] Filed: Jun. 14,1996
Related U.S. Application Data
[63] Continuation-in-part of Set. No. 259,461, Jun. 14,1994, Pat
No. 5,562,932.
[51] fat CL6 B29C 51/10; B29C 51/22
[52] U.S. CI 425/290; 264/504; 425/388
[58] Field of Search 425/290. 388;
264/504
[56] References Cited
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Primary Examiner—Robert Davis
Attorney, Agent, or Firm—Enoch, Schaffer, Schaub & Porcello Co.. L.P.A.
[57] ABSTRACT
A cylindrical screen for perforating a thermoplastic film or sheets has an outer surface and an inner surface. A plurality of outer apertures extend from the outer surface and terminate at a corresponding inner aperture on the inner surface of the screen. The apertures in the outer surface can have the same or a different geometrical shape as the apertures in the inner surface. The apertures form a passageway through the screen. The passageways are disposed at least one angle from about 5° to about 60° with respect to a plane that is disposed substantially perpendicular to the outer surface of the screen to prevent a direct line of sight through the screen.
27 Claims, 8 Drawing Sheets
