GB1598725A - Connection flange for a wing of an aircraft or space vehicle - Google Patents

Description

(54) A CONNECTION FLANGE FOR A WING OF AN AIRCRAFT OR SPACE VEHICLE (71) We, MEssERscHMITT-BoLKow- BLOHM Gesellschaft mit beschränkter Haftung, of 8000 München, German Federal Republic, a Company organised and existing under the laws of the German Federal Republic, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a connection flange for a wing of an aircraft or space vehicle, the wing being of the type laminated from metallic and non-metallic materials.

Wing support structures of fibre-reinforced composite plastics materials have already become known from German Specifications Nos. 2032283 and 2109692. The first specification mentioned describes a support structure of individual tubular elements made of fibre-reinforced plastics. The fibrous reinforcement used consists of carbon fibres.

The tubular elements are interconnected and reinforced by means of strips of plastics material.

The second specification mentioned describes a hollow wing constructed by the composite method and consisting of a shell of fibre-reinforced material affixed by an adhesive to metal strips providing a cellular structure. The shell, of Boron fibre reinforced (BFK) material, titanium-quartz elements and aluminium ribs form a certain definite proportion of the number of layers in the fibre-reinforced matrix material. It is true that the aforementioned designs are intended to enable aircraft wing units to be made of a plastics material, but the wing connection construction in these cases has to be very expensive and is also too heavy to be capable of taking up the forces to be transmitted.

German Specification No. 1,781,322 makes known a laminated wing structure in which very strong metallic and non-metallic layers of material are interconnected by an adhesive, are situated in vertical planes and decrease in length with their distance from the root edge of the wing resulting in a support means of which the width decreases in stages. In this structure the non-metallic layers are resin-impregnated fibre mats. Each of the individual construction elements, however, is subjected both to compressive forces and to tensile forces, as well as to transverse and torsional forces. The very principle of this design necessitates a considerably reinforced construction, preventing the advantages of the composite fibrous materials from being utilised to the full.

The purpose of the present invention is to provide a connection flange in which each of the elements used will be subjected either to traction only or to pressure only.

According to the invention there is provided a connection flange for a wing of an aircraft or space vehicle, the wing being a laminated structure built up from layers of metallic and non-metallic materials, the flange comprising a plurality of metal thimbles, a sleeve passing through respective apertures therefore in the thimbles to maintain the thimbles in side-by-side relation, the interior of the sleeve providing an opening of the flange through which a bolt can be passed to bolt the wing to the fuselage of the aircraft or space vehicle, each thimble supporting the looped ends of respective strands of filamentary material, each such strand being bent to U-shape about the associated thimble and its two arms extending therefrom to be incorporated in the laminated structure of the wing, there being provided to extend from the wing into contact with each thimble a pressure-resistant core located between the two arms of each looped strand supported thereby.

Preferably the thimbles have flat opposite side faces, the thimbles being in a stacked relation on the sleeve with respective side faces of adjacent thimbles opposed to one another, and each said side face of each thimble is preferably formed with a series of parallel U-shaped grooves to receive respective strands of filamentary material.

The end surface of each pressure-resistant core in contact with the associated thimble is preferably rounded to be received in a rounded recess in the thimble.

Each pressure-resistant core preferably tapers to its end remote from the associated thimble.

Each pressure-resistant core is preferably of a composite material with a metallic matrix.

The strands are preferably of wound BFK yarn threads and the U-shape of each strand, to which a support surface therefor on the associated thimble conforms, is preferably such that the two arms of the strand extend in directions in which tension forces will be generated when the wing in which they are incorporated is placed under load.

This structure not only provides a stepless transition from the composite fibrous structure to the laminations of the wing but also ensure continuity in the course taken by the forces.

As the fibre strands of the loops take the course appropriate to each force to be taken up, each individual constructional element is only subject to one force, being relieved of additional forces, the said loops being dimensioned and constructed, as regards their shape, and size, in accordance with the particular force to be absorbed.

The means available for taking up transversal forces for this connection are the crosspieces of the wing itself. Separate connection points are used for the absorption of torsional forces.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a wing having a connection flange according to the invention, Figure 2 is a cross-section taken along the line A-A of Figure 1, Figure 3 is a section view in a horizontal plane of the connection flange, and Figure 4 is a view taken along the line B-B of Figure 3.

Figure 1 illustrates in perspective a wing 10 of an aircraft having laminations 11, 12, 13, etc., differing in shape and size. These laminations are incorporated in the wing structure and hardened.

Figure 2 is a section on a larger scale along the line A-A of Figure 1 and shows how a series of metal thimbles 15 (Figures 3 and 4) are held in coaxial relation by a single bearing sleeve 16a passed through them.

Figures 3 and 4 are schematic diagrams of one of the superimposed sub-structures making up the connection of Figure 2. A specially shaped two-sided metal thimble 15 is provided with a bore 16 which will receive the sleeve 1 6a for the bolt connection on the fuselage and with recesses 17 in its opposite sides accommodating respective strands 18 of carbon fibre reinforced (KFK) filamentary material. A tapered pressure-resisting body 20 made of composite fibrous material is situated between the two arms of each looped strand 18. The inner surface of the thimble 15 presented to the body 20 is concave, assisting the transmission of forces when a compressive stress is applied to the wing.

The end of the body 20 in contact with the metal thimble 15 is at 19 and is preferably made of BFK material. A force-distributing medium in the form of a hardenable filler, for instance, can be interposed between the contacting surfaces of the body 20 and metal thimble 15. In order to obtain a further saving of weight the body 20 can be hollow, its interior space being filled with a suitable foam.

The looped strands 18 of KFK material are made up of individual filaments or yarns which rest in the recesses 17 of the metal thimble 15 to take up tensile forces. The resulting structures 11, 12, 13 are incorporated in the laminata structure of the wing, thus ensuring the distribution of forces over and area. As a force-absorbing element is produced and appropriately shaped for each of the forces occuring, the durability and thus the safety and wear-resistance of the system is greatly increased.

WHAT WE CLAIM IS: 1. A connection flange for a wing of an aircraft or space vehicle, the wing being a laminated structure built up from layers of metallic and non-metallic materials, the flange comprising a plurality of metal thimbles, a sleeve passing through respective apertures therefor in the thimbles to maintain the thimbles in side-by-side relation, the interior of the sleeve providing an opening of the flange through which a bolt can be passed to bolt the wing to the fuselage of the aircraft or space vehicle, each thimble supporting the looped ends of respective strands of filamentary material, each such strand being bent to U-shape about the associated thimble and its two arms extending therefrom to be incorporated in the laminated structure of the wing, there being provided to extend from the wing into contact with each thimble a pressure-resistant core located between the two arms of each looped strand supported thereby.

2. A connection flange as claimed in claim 1, wherein the thimbles have flat opposite side faces, the thimbles being in a stacked relation on the sleeve with respective side faces of adjacent thimbles opposed to one another, and wherein each said side face

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. another, and each said side face of each thimble is preferably formed with a series of parallel U-shaped grooves to receive respective strands of filamentary material. The end surface of each pressure-resistant core in contact with the associated thimble is preferably rounded to be received in a rounded recess in the thimble. Each pressure-resistant core preferably tapers to its end remote from the associated thimble. Each pressure-resistant core is preferably of a composite material with a metallic matrix. The strands are preferably of wound BFK yarn threads and the U-shape of each strand, to which a support surface therefor on the associated thimble conforms, is preferably such that the two arms of the strand extend in directions in which tension forces will be generated when the wing in which they are incorporated is placed under load. This structure not only provides a stepless transition from the composite fibrous structure to the laminations of the wing but also ensure continuity in the course taken by the forces. As the fibre strands of the loops take the course appropriate to each force to be taken up, each individual constructional element is only subject to one force, being relieved of additional forces, the said loops being dimensioned and constructed, as regards their shape, and size, in accordance with the particular force to be absorbed. The means available for taking up transversal forces for this connection are the crosspieces of the wing itself. Separate connection points are used for the absorption of torsional forces. A preferred embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a wing having a connection flange according to the invention, Figure 2 is a cross-section taken along the line A-A of Figure 1, Figure 3 is a section view in a horizontal plane of the connection flange, and Figure 4 is a view taken along the line B-B of Figure 3. Figure 1 illustrates in perspective a wing 10 of an aircraft having laminations 11, 12, 13, etc., differing in shape and size. These laminations are incorporated in the wing structure and hardened. Figure 2 is a section on a larger scale along the line A-A of Figure 1 and shows how a series of metal thimbles 15 (Figures 3 and 4) are held in coaxial relation by a single bearing sleeve 16a passed through them. Figures 3 and 4 are schematic diagrams of one of the superimposed sub-structures making up the connection of Figure 2. A specially shaped two-sided metal thimble 15 is provided with a bore 16 which will receive the sleeve 1 6a for the bolt connection on the fuselage and with recesses 17 in its opposite sides accommodating respective strands 18 of carbon fibre reinforced (KFK) filamentary material. A tapered pressure-resisting body 20 made of composite fibrous material is situated between the two arms of each looped strand 18. The inner surface of the thimble 15 presented to the body 20 is concave, assisting the transmission of forces when a compressive stress is applied to the wing. The end of the body 20 in contact with the metal thimble 15 is at 19 and is preferably made of BFK material. A force-distributing medium in the form of a hardenable filler, for instance, can be interposed between the contacting surfaces of the body 20 and metal thimble 15. In order to obtain a further saving of weight the body 20 can be hollow, its interior space being filled with a suitable foam. The looped strands 18 of KFK material are made up of individual filaments or yarns which rest in the recesses 17 of the metal thimble 15 to take up tensile forces. The resulting structures 11, 12, 13 are incorporated in the laminata structure of the wing, thus ensuring the distribution of forces over and area. As a force-absorbing element is produced and appropriately shaped for each of the forces occuring, the durability and thus the safety and wear-resistance of the system is greatly increased. WHAT WE CLAIM IS:

1. A connection flange for a wing of an aircraft or space vehicle, the wing being a laminated structure built up from layers of metallic and non-metallic materials, the flange comprising a plurality of metal thimbles, a sleeve passing through respective apertures therefor in the thimbles to maintain the thimbles in side-by-side relation, the interior of the sleeve providing an opening of the flange through which a bolt can be passed to bolt the wing to the fuselage of the aircraft or space vehicle, each thimble supporting the looped ends of respective strands of filamentary material, each such strand being bent to U-shape about the associated thimble and its two arms extending therefrom to be incorporated in the laminated structure of the wing, there being provided to extend from the wing into contact with each thimble a pressure-resistant core located between the two arms of each looped strand supported thereby.

2. A connection flange as claimed in claim 1, wherein the thimbles have flat opposite side faces, the thimbles being in a stacked relation on the sleeve with respective side faces of adjacent thimbles opposed to one another, and wherein each said side face

of each thimble is formed with a series of parallel U-shaped grooves to receive respective strands of filamentary material.

3. A connection flange as claimed in either preceding claim wherein the end surface of each pressure-resistant core in contact with the associated thimble is rounded to be received in a rounded recess in the thimble.

4. A connection flange as claimed in any preceding claim wherein each pressure-resistant core tapers to its end remote from the associated thimble.

5. A connection flange as claimed in any preceding claim, wherein each pressure-resistant core is of a composite material with a metallic matrix.

6. A connection flange as claimed in any preceding claim, wherein the strands are of wound KFK yarn threads and wherein the U-shape of each strand, to which a support surface therefor on the associated thimble conforms, is such that the two arms of the strand extend in directions in which tension forces will be generated when the wing in which they are incorporated is placed under load.

7. A connection flange for a wing of an aircraft or space vehicle substantially as herein described with reference to and as illustrated in the accompanying drawings.