US 5,707,576 AGranted

Process for the fabrication of composite hollow crown-stiffened skins and panels

AssigneeBoeing North American, Inc.

InventorDon L. Asher

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Abstract

A process for forming composite hollow crown stiffened skins and panels in which a first layer or skin is placed on a forming surface of a female mold and, after forming a plurality of U-shaped stiffener elements in the first skin, a second skin is placed over the first skin, whereupon the resulting assembly is prepared for autoclave curing. The stiffener elements are formed by pressing the first skin into U-shaped depressions in the female mold surface and inserting a hollow, expandable rubber mandrel into each of the depressions on top of the first skin. Valve stems in the mandrels enable maintaining the pressure inside at atmospheric pressure. The mandrels are maintained in their "pressurized" state during subsequent formation and autoclave curing steps.

Claims3

Dependent claims

A method for forming a unitary panel structure from fiber-reinforced composite material, comprising the steps of:

(a) forming a first subassembly on a tool, said first subassembly including a first skin and a plurality of channel-shaped elements, the channel-shaped elements being disposed atop the skin and being aligned with one another, said channel-shaped elements having inflatable mandrels disposed therein and secured to a surface of said tool, the channel-shaped elements and the first skin comprising said composite material,
(b) forming a second assembly comprising the first subassembly and a second skin of composite material, the first and second skins being disposed on opposite sides of said channel-shaped elements, and
(c) inflating said mandrels while curing said second subassembly in an autoclave at a temperature not greater than 350.degree. F. to form a unitary, one-piece panel structure.

Dependencies are inferred from the claim text.

Facts

Application: 08/475,696Filed 7 Jun 1995 · division
Priority: 4 Oct 1994
Granted: 13 Jan 1998
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

B29D 99/001
Subject matter not provided for in other groups of this subclass: producing wall or panel-like structures, e.g. for hulls, fuselages, or buildings
B29C 70/446
Using isostatic pressure, e.g. pressure difference-moulding, vacuum bag-moulding, autoclave-moulding or expanding rubber-moulding: moulding…
B29D 99/0014
Producing wall or panel-like structures, e.g. for hulls, fuselages, or buildings: provided with ridges or ribs, e.g. joined ribs
Y10S 428/902
Stock material or miscellaneous articles: high modulus filament or fiber

Family

Serial317,452Parent of this division · filed 4 Oct 1994
US 5,622,733 AParent of this division
US 5,707,576 AThis patent

From the US filing history. Foreign family members aren’t listed.

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