Joseph M Donckers

US Patent:

60714441, Jun 6, 2000

Filed:

Nov 24, 1997

Appl. No.:

8/979447

Inventors:

William J. Worrell - Draper VA
David A. Worrell - Radford VA
Joseph M. Donckers - Blacksburg VA

Assignee:

Alliant Techsystems Inc. - Hopkins MN

International Classification:

B29C 6700

US Classification:

264 31

Abstract:

A method of producing a perforation pattern in a slab of thermoplastic propellant material and the material produced includes subjecting the slab to a perforating press operation in which the press has a patterned array of fixed perforating members arranged according to a first pattern coordinated with a system for advancing and incrementally indexing the slab through the press is used to perforate the slab to create a desired second, denser perforation pattern by subjecting the slab to a series of perforation actions by the patterned array of perforating means coordinated with the indexing of the slab through the press.