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:
Sep. 22, 1998
Filed:
Sep. 03, 1996
Raymond J Palmer, Newport Beach, CA (US);
Gert Wagener, Emsdetten, DE;
McDonnell Douglas Corporation, St. Louis, MI (US);
Abstract
An improved warp/knit stitch reinforced multi-axial non-crimp layered fabric sheet used in structural applications, as for example, in aircraft and water applications, e.g. the skin of an airplane wing or fuselage structure, in water applications, e.g. skins of surfboards and boats, and in other areas where high strength and relatively light weight is required. The fabric is comprised of a plurality of plies facewise disposed upon one another and knitted or stitched to form a structural sheet. Each fabric ply is made of strands of aligned structural fibers which can be later impregnated and even pre-impregnated with a resin curable matrix. The improved sheet is formed by applying unidirectional non-crimp and non-woven plies of different angular relationship to one another, e.g. a +45.degree., a 90.degree. and a -45.degree. ply and locating 0.degree. plies in essentially any position in the ply arrangement such that the 0.degree. ply can be on the bottom of the sheet, on top of the sheet, or interposed between plural ply layers of the sheet. The sheets are then knitted or stitched together to make a stack of multi-axial fabric layers. The fiber weight and thickness can also be varied throughout the sheets by using plies of different thicknesses or differing weights of fibers. Moreover, the percentage of a certain type of fiber in a particular ply can be varied. In addition, damage tolerance can be built into the cured laminate. Further, doublers and local area reinforcements can also be included in the sheet. In addition, a warp/knit, or warp/stitched fabric may be made to a desired width without otherwise affecting the structural properties of the sheet. An apparatus and a method for producing the fabric sheets is also disclosed.