Method of making composite material stiffeners

• US 8,205,567 B2
• Filed: 03/07/2008
• Issued: 06/26/2012
• Est. Priority Date: 03/16/2007
• Status: Active Grant

• Current Assignee: Safran Landing Systems
• Original Assignee: Messier-Bugatti-Dowty
• Inventors: Dunleavy, Patrick
• Primary Examiner(s): Izaguirre, Ismael
• Application Number:
  US12/531,565
• Publication Number:
  US 20100096067A1
• Time in Patent Office: 1,572 Days
• Field of Search: 112/475.06, 112/475.08, 112/475.17, 112/440, 428/102, 428/85, 156/93, 264/510
• US Class Current: 112/475.08
• CPC Class Codes: B29C 53/04 of plates or sheets B29C63/04 takes precedence; bending or folding paper B31F1/0003; folding films B65H45/00
• CPC Class Codes: B29C 70/34 and shaping or impregnating by compression , i.e. combined with compressing after the lay-up operation
• CPC Class Codes: B29C 70/543 Fixing the position or configuration of fibrous reinforcements before or during moulding for non-woven fabrics D04H3/08
• CPC Class Codes: B29C 70/545 Perforating, cutting or machining during or after moulding
• CPC Class Codes: B29D 99/0014 provided with ridges or ribs, e.g. joined ribs
• CPC Class Codes: B29L 2031/3082 Fuselages
• CPC Class Codes: Y02T 50/40 Weight reduction
• CPC Class Codes: Y10T 428/24033 including stitching and discrete fastener[s], coating or bond

Abstract

A method of making at least one stiffener element includes cutting out two substantially identical elongate flanks from fiber plates, each flank presenting two lateral projections on either side of a central portion. The flanks are superimposed with one another and stitched together along two parallel lines that mark the boundaries between the lateral projections and the central portions. The lateral projections are folded along the lines of stitching to either side of the assembly in order to form flanges.

Claims

1. A method of making at least one stiffener element, the method comprising the steps of:

cutting out two substantially identical elongate flanks (2, 4) from fiber plates, each flank presenting two lateral projections (10, 14) on either side of a central portion (6);

superposing the flanks (2, 4) and stitching them together along two parallel lines (8, 12) that mark the boundaries between the lateral projections and the central portions; and

folding the lateral projections (10, 14) along the lines of stitching to either side of the assembly as formed in this way in order to form flanges (22, 24),

wherein the central portions (6) of the flanks extend beyond the lateral projections in order to define at least at one free end (16, 18) of the stiffener element.

2. A method according to claim 1, wherein at least one reinforcing element (30, 32, 34) cut out from a fiber plate is stitched on the free end and is stitched at the free end.

3. A method according to claim 2, wherein a plurality of reinforcing elements (30, 32, 34) are stitched on either side of the free end.

8. A method of making a stiffened panel, the method comprising the steps of:

cutting a panel (60) out from a fiber plate;

making a stiffener element according to claim 1 or according to claim 5; and

placing the stiffener element on the panel and stitching the flanges of the stiffener element that face the panel thereto.

4. A method of making a stiffener element, the method comprising the steps of:

cutting out two substantially identical elongate flanks (2a, 4a) from fiber plates, each flank presenting two lateral projections (10a, 14a) on either side of a central portion (6a);

superposing the flanks (2a, 4a) and stitching them together along two parallel lines (8a, 12a) that mark the boundaries between the lateral projections and the central portions in order to obtain a first stiffener blank (40a);

cutting out two substantially identical elongate flanks (2b, 4b) from fiber plates, each flank presenting two lateral projections (10b, 14b), on either side of a central portion (6b), the flanks presenting at least one free end (16b);

superposing the flanks (2b, 4b) and stitching them together along two parallel lines (8b, 12b) that mark the boundaries between the lateral projections and the central portions in order to obtain a second stiffener blank (40b);

superposing the two stiffener blanks so that the free end (16b) of the second stiffener blank (40b) faces the central portion (6a) of the first stiffener blank (40a);

stitching the free end (16b) of the second stiffener blank to the central portion of the first stiffener blank;

folding the second stiffener blank (40b) in such a manner that it extends transversely relative to the first stiffener blank; and

folding the lateral projections (10a, 14a, 10b, 14b) at right angles along the lines of stitching (8a, 12a, 8b, 12b) so that the lateral projections form flanges (22a, 24a, 22b, 24b).

5. A method according to claim 4, wherein reinforcing strips (52a, 52b) cut out from a fiber plate are sewn onto the flanges.

6. A method according to claim 5, wherein the reinforcing strips (52a, 52b) cross at a junction of the stiffener element.

7. A method according to claim 4, wherein a reinforcing cross (72) cut out from a fiber plate is sewn onto the flanges at a junction of the stiffener element.