The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 17, 1987
Filed:
Nov. 06, 1984
Alain Brasquies, Bergerac, FR;
Michel Maures, Bergerac, FR;
Societe Nationale des Poudres et Explosifs, Paris, FR;
Abstract
This invention relates to combustible or semi-combustible cases intended in particular for artillery ammunition. More specifically, the invention relates to combustible cases bodies obtained by spirally winding combustible paper tapes containing nitrocellulose and having an improved mechanical resistance relative to previous combustible tape bodies, thanks to the fact that the combustible paper tapes form three distinct coaxial layers in terms of their density and structure. The case bodies according to the invention are obtained by spiral winding around a mandrel 80 a sheet 70 consisting of an uncalendered combustible paper tape 41 and six calendered combustible paper tapes 42-47 with density between 0.9 and 1.2 g/cm.sup.3, the tapes being pasted to each other according to a helical angle .alpha. such that the helical pitch P is larger than the width w1 of the tape 41 which thus forms a helix with turns which are not joined together. A calendered combustible paper tape 71 previously pasted with density lying between 1.15 g/cm.sup.3 and 1.3 g/cm.sup.3 is then spirally wound around the tube thus formed according to the a helical angle .beta. such that the turns of the helix formed by the said tape 71 overlap. The tube thus formed is then cut to the desired length of the case body.