Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C1/00—Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like
  • B64C1/06—Frames; Stringers; Longerons ; Fuselage sections
  • B64C1/12—Construction or attachment of skin panels

Definitions

• This invention concerns a device for bracing a shell surface in an aircraft fuselage against deformations and consisting of a continuous profile that is arranged so as, after conformation, to be mounted against the shell surface.
• a stringer is often used in thin-sheet structures to brace a shell surface against deformations perpendicular to the sheet surface.
• Panels or outer sections with an outer surface part in the aircraft are equipped with supporting ribs. When these supporting ribs are disposed longitudinally, the term "stringer" is used. The purpose of these supporting ribs is to divide the aircraft surfaces into an optimal configuration so as to counteract deformation of the fields between the stringers.
• stringers One problem with using stringers is that it is very expensive to produce stringers whose geometry conforms to the location in the aircraft where the element is to be used. When the surface of the fuselage is curved it is necessary to either mill or stretch the stringer into the desired shape, which is very expensive.
• a continuous profile of, e.g. light metal is used as a stringer.
• Notches are made at a regular distance apart from each other in at least a portion of the profile.
• the notches extend through a base surface in the profile and through an intermediate part in the direction perpendicular to the base surface.
• the profile also contains an upper surface that is parallel to said base surface, which upper surface is not encompassed by said notches.
• the stringer according to the invention When the stringer according to the invention is being mounted against the shell surface, it can be easily bent and conformed to the shape of the shell surface. After mounting, the stringer and the shell surface together form a strong and rigid unit.
• One advantage of the solution according to the invention is that both the stringer and the shell surface are soft and workable prior to their being assembled together, while the finished assembled structure is strong and stable.
• the workable stringer radically affects durability and strength vis-a-vis loads that are perpendicular to a sheet surface, while the costs of conforming the stringer can at the same time be kept at a very low level.
• FIGURES Figure 1 Perspective view of mounted stringer Figure 2 Side view of mounted stringer
• FIGS. 2a - 2b Sectional view of a mounted stringer
• a stringer 2 can consist of a continuous profile of workable material, such as an extruded aluminum profile.
• Figures 3a - 3d show a number of possible cross-sections for such a profile.
• the cross-section consists of a base 3 and an intermediate part 4 oriented perpendicular thereto, plus an upper surface parallel to the base 3.
• Designs involving a base 3, an intermediate part 4 and an upper surface 5 other than those shown in the figures are also possible.
• a typical thickness d for the walls of the profile is roughly 1 - 2 mm. The thickness of the base, the intermediate part and the upper surface may differ.
• notches 6 are made at predetermined distances apart from each other along the length of the profile. In a preferred embodiment these notches 6 are spaced at a regular distance a apart from each other in order to thereby render the stringer structure independent of the shape of the aircraft section in which the structure is to be used.
• An appropriate distance between the notches can be roughly 25 mm, but this distance is of course dependent on the shell surface against which the stringer is to be mounted. It is also possible to make notches with varying distances between them along different portions of the length of the profile.
• the notches can extend through the base surface 3 and the intermediate part 4 in the direction perpendicular to the base surface 3.
• the notches are delimited upwardly by the upper surface 5, which thus is not encompassed by said notches 6.
• the base surface 3 and the upper surface 5 are joined via said intermediate part and realized in one piece therewith.
• the notches can be, e.g. milled or cut from the original profile. Stringers with notches can also be fabricated as yard goods, i.e. at low cost.
• Figure 1 shows a perspective view of two stringers 2 mounted against a shell surface 1. Mounting can be accomplished by various methods, such as riveting, bolting, welding or gluing. Once the stringer is mounted against the shell surface, the frame ribs can be secured in the usual way.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Aviation & Aerospace Engineering (AREA)
• Moulding By Coating Moulds (AREA)
• Tires In General (AREA)
• Laminated Bodies (AREA)
• Reciprocating Pumps (AREA)
• Catching Or Destruction (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Connection Of Plates (AREA)
• Body Structure For Vehicles (AREA)
• Fuses (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20284386

Family Applications (1)

Country Status (7)

Cited By (6)

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Citations (2)

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• 2001
  • 2001-06-05 SE SE0102009A patent/SE0102009L/ not_active IP Right Cessation
• 2002
  • 2002-04-23 DE DE60218664T patent/DE60218664T2/de not_active Expired - Lifetime
  • 2002-04-23 AT AT02776541T patent/ATE356020T1/de not_active IP Right Cessation
  • 2002-04-23 ES ES02776541T patent/ES2281546T3/es not_active Expired - Lifetime
  • 2002-04-23 US US10/479,663 patent/US7124982B2/en not_active Expired - Fee Related
  • 2002-04-23 WO PCT/SE2002/000787 patent/WO2002098733A1/en active IP Right Grant
  • 2002-04-23 EP EP02776541A patent/EP1397289B1/en not_active Expired - Lifetime

Patent Citations (2)

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