Shear strap connector system and method for installing a shear strap connector system

Abstract

A shear strap connector system for securing a frame member to a composite fuselage skin includes a shear strap connector and a fuselage mandrel defining a slot within which the shear strap connector is positioned.

Description

Technical Field

[0001] This disclosure relates to securing structures to composite walls, and more specifically to securing internal structures of an aircraft (such as frames) to composite fuselage skin using connectors. Background Technology

[0002] In aircraft manufacturing, the aircraft's internal structures, such as frame components, are attached to the aircraft's composite fuselage skin. When attaching the frame components to the composite fuselage skin, straight-shank fasteners pass through the skin from the outside and are positioned to secure to shear tie connectors located on the inside of the composite fuselage skin. The shear tie connectors are then fastened to the frame components inside the aircraft using fasteners.

[0003] When securing the aircraft frame components to the composite fuselage skin, the process requires drilling holes through the composite fuselage skin and through the skin-side portion of the shear band connector. The shear band connector is secured to the composite fuselage skin using fasteners with straight shanks, and sealant is applied to seal the holes formed in the composite fuselage skin. Another hole is drilled in the frame-side portion of the shear band connector, and the frame components are typically attached to the frame side of the shear band using straight-shank fasteners.

[0004] Aircraft assembly requires drilling numerous holes in the composite fuselage skin. Drilling holes through the composite fuselage skin, through the skin side of the shear band connector, and securing the shear band connector with fasteners positioned through the composite fuselage skin is a time-consuming task. The numerous fasteners used to secure the shear band connector to the composite fuselage skin add significant weight to the aircraft, and the sealant used in conjunction with the fastener connection also contributes to the weight. Further drilling is required on the frame side of the shear band connector to connect the frame components via holes in the frame components using straight-shank fasteners.

[0005] Drilling numerous holes through the composite fuselage skin weakens the fuselage structure. Without the need for drilling to connect the composite fuselage skin to shear belt connectors, the fuselage structure becomes relatively more robust. As a result, the composite fuselage skin can be constructed thinner to provide the required strength. Additionally, the thinner fuselage structure with the composite fuselage skin reduces weight and leads to lower costs in both aircraft construction and operation. Similarly, without drilled holes extending through the composite fuselage skin, the internal air pressure can be better contained, potentially allowing for passenger pressurization at lower altitudes for added comfort.

[0006] As a result, there is a need to construct an aircraft with a composite skin fuselage that eliminates the need for numerous holes penetrating the fuselage skin while still securing the aircraft's frame components to the composite skin. Eliminating these holes for securing the frame components to the composite fuselage will reduce aircraft construction time and costs. Furthermore, eliminating the need for fasteners used to secure shear band connectors will reduce aircraft weight and associated operating costs, and provide opportunities to increase passenger comfort. Summary of the Invention

[0007] One example includes a shear strip connector system for securing frame components to a composite fuselage skin, the system comprising a shear strip connector and a fuselage body shaft defining a slot therein where the shear strip connector is located.

[0008] One example includes a method for installing a shear band connector system, the method comprising positioning the shear band connector into a slot defined by the body axis of the machine.

[0009] The features, functions, and advantages already discussed can be implemented independently in various embodiments or combined in other embodiments, further details of which can be seen in the following description and figures. Attached Figure Description

[0010] Figure 1 A perspective view of the aircraft;

[0011] Figure 2 For use in construction Figure 1 An internal side perspective view of part of the fuselage body axis of an aircraft.

[0012] Figure 3 for Figure 2 An external side perspective view of a portion of the body axis of the machine, wherein the shear band is in an exploded view relative to the body axis of the machine;

[0013] Figure 4 For along Figure 3 The figure shows a cross-sectional view taken by line 4-4, which illustrates an example of a shear band connector retaining assembly in a shear band receiver, which is used to retain the shear band connector in a receiver on the fuselage body axis during the stacking of composite panels of the fuselage skin.

[0014] Figure 5 for Figure 4 The view shows the shear band connector held within the receiver on the body shaft;

[0015] Figure 6 for Figure 5 The view shows the composite fuselage skin positioned on the fuselage body axis;

[0016] Figure 7 for Figure 6 The view shows that the composite fuselage skin has been cured and the aircraft frame has been secured to the skin side portion of the shear belt connector; and

[0017] Figure 8 This is a flowchart for securing shear band connectors to the composite fuselage skin of an aircraft. Detailed Implementation

[0018] As previously discussed, there is a need to construct an aircraft with a composite skin fuselage that does not have numerous holes penetrating the composite skin while still securing the aircraft frame to the composite skin. Such a construction would offer numerous cost-saving benefits in aircraft manufacturing and operation.

[0019] refer to Figure 1 The aircraft 10 has a fuselage 12, which provides other structures within the aircraft 10, such as, for example, the frame components of the aircraft 10. Figure 1 (Not shown in the diagram). As previously described, the frame component is secured to the fuselage 12 by drilling holes in the fuselage 12 using shear band connectors and by fastening straight shank fasteners to secure the shear band connectors to the fuselage 12. The shear band connectors are then secured to the frame component, thereby forming a fixation between the frame and the fuselage 12. However, this results in drilling a large number of holes through the fuselage 12 for positioning.

[0020] Reference Figure 2-5 At the same time, the shear belt connector system 14 used to fix the frame 16 to the composite fuselage skin 18 is as follows: Figure 6 and Figure 7 As shown. The shear band connector system 14 includes a shear band connector 20 and a body shaft 22, the body shaft 22 defining a slot 24 therein where the shear band connector 20 is located. In this example, the shear band connector 20 is made of a cured composite material and includes a skin side panel member 26 and a frame side panel member 28 extending from the skin side panel member 26. The frame side panel member 28 extends in a direction 30 relative to the transverse direction of the skin side panel member 26.

[0021] The shear band connector system includes a plurality of slots 24 defined by the body shaft 22, such as Figure 3As shown, these slots 24 are positioned spaced apart from each other. The plurality of slots 24 are positioned along the circumferential line 32 of the body axis 22. Each of the plurality of slots 24 defines a length dimension "L1" extending along the circumferential line 32 of the body axis 22, which is greater than the length dimension "L2" of the shear band connector 20. Each of the plurality of slots 24 defines a width dimension "W1" extending in a direction 34 transverse to the circumferential line 32 of the body axis 22. The width dimension "W1" of each of the plurality of slots 24 is greater than the width dimension "W2" of the shear band connector 20. When the length dimension "L1" of the slot 24 is greater than the length dimension "L2" of the shear band connector 20 and the width dimension "W1" of the slot 24 is greater than the width dimension "W2" of the shear band connector 20, the shear band connector 20 can be inserted into the slot 24. Figure 4 and 5 As shown, the slot 24 includes a recessed surface 36 located within the body shaft 22 and spaced apart from the outer surface 38 of the body shaft 22. Figure 5 As shown, the first portion 40 of the recessed surface 36 extends along the slot 24 such that, with the shear band connector 20 positioned within the slot 24, the skin side panel member 26 of the shear band connector 20 extends along the first portion 40 of the slot 24 without extending outside the slot 24 or otherwise above the outer surface 38. In this example, the shear band connector 20 is positioned slightly below the outer surface 38 of the body axis 22 to at least accommodate an adhesive layer positioned to cover the skin side panel member 26 and aligned with the outer surface 38 of the body axis 22, as will be discussed further herein.

[0022] like Figure 4 and 5 As shown, the slot 24 includes a second portion 42 that extends in a direction 44 transverse to the first portion 40 of the slot 24 and extends away from the outer surface 38 of the body shaft 22. The second portion 42 of the slot is defined by a pair of spaced-apart sidewall portions 46 of the body shaft 22 and an endwall portion 48 extending between the pair of spaced-apart sidewall portions 46. The second portion 42 of the slot 24 accommodates the frame sideplate member 28 of the shear band connector 20.

[0023] refer to Figure 2 , 4 , 6 and 7, and Figure 3Conversely, the inner side 23 of the body shaft 22 is visible, opposite to the outer side 25 of the body shaft 22. On the inner side 23 of the body shaft 22, the outer surfaces 27 of a pair of spaced-apart sidewall portions 46 and the outer surface 29 of an endwall portion 48 are visible. Additionally, the outer surface 31 of the body shaft 22 is visible, positioned in relation to the recessed surface 36 of the slot 24.

[0024] refer to Figure 4 and 5 The retaining member 50 is positioned within the second portion 42 of the slot 24. In this example, the retaining member 50 includes an inflatable airbag 52. Figure 4 In the middle, the inflatable airbag 52 is not fully inflated, and the frame side plate member 28 is positioned within the second part of the slot 24, as... Figure 5 As shown, the inflatable airbag 52 is inflated from a pressurized air source 54. Inflating the inflatable airbag 52 causes it to apply a force “F” to the frame side panel member 28, thereby pushing the frame side panel member 28 against one of a pair of spaced-apart side wall portions 46. As a result, the shear band connector 20 is held and secured within the slot 24. This holding serves to position the shear band connector 20 anywhere around the fuselage body axis 22 without subjecting it to any movement due to gravity, which affects the positioning and securing of the shear band connector 20 when the composite material is wrapped during the construction of the fuselage 12. Many different types of holding members can be used to hold the shear band connector 20 in the slot 24. These holding members may include, for example, springs, washers, or other items that are placed within the slot 24 and secure the shear band connector 20 within the slot 24. Additionally, as... Figure 5 As shown, the first composite gap filler 53 and the second composite gap filler 55 are located within the slot 24, thereby filling the gap between the shear belt connector 20 and the fuselage body shaft 22. When the first composite gap filler 53 and the second composite gap filler 55 are installed in alignment with the outer surface 38 of the fuselage body shaft 22, this alignment with the outer surface 38 prevents undulations in the fuselage skin 18 caused by the curing of the first composite gap filler 53 and the second composite gap filler 55 during the co-bonding of the fuselage skin 18 and the shear belt connector 20.

[0025] like Figure 6 and Figure 7 As shown, in this example, the shear band connector system 14 further includes an adhesive 56 positioned to cover the skin side panel member 26 of the shear band connector 20. Figure 6As shown, adhesive 56 plays a crucial role in co-bonding the cured shear band connector 20 to the uncured fuselage skin 18, and promotes co-bonding of the components through chemical adhesives, making the co-bonded component resemble a single part rather than two separate parts fixed together. Many different constructions of the fuselage skin 18 can be employed, including composite materials that cover the shear band connector 20, the slot 24, and the fuselage body shaft 22. For example... Figure 6 As shown, in the example of fuselage skin 18, fuselage skin 18 may include an tackifier (not shown) that covers adhesive 56 and fuselage body shaft 22. The tackifier is positioned to cover adhesive 56 and fuselage body shaft 22 to reduce panel displacement during assembly. The composite material is positioned in a covering relationship relative to the tackifier. In various configurations of fuselage skin 18 chosen by the manufacturer, other materials may be positioned between the composite material and the tackifier, where the composite material is still considered to be in a covering relationship relative to the tackifier. With the shear band connector system 14 assembled, a co-bonding is performed to secure the shear band connector 20 to the composite fuselage skin 18, as shown. Figure 7 As shown, the composite fuselage skin has been cured, and the co-bonding provides fixation between the shear band connector 20 and the cured fuselage skin 18 without drilling through the fuselage 12 and extending fasteners through the fuselage 12. In the case of securing the shear band connector 20 to the fuselage skin 18, the fuselage body shaft 22 can be removed from the fuselage skin 18, for example, by collapsing the body shaft 22. Figure 7 As shown, frame 16 is secured to frame side panel member 28 with fastener 68.

[0026] like Figure 8 As shown, a method 64 for installing the shear band connector system 14 includes positioning the shear band connector 20 66 into a slot 24 defined by the fuselage body axis 22. The shear band connector 20 includes a skin side panel member 26 and a frame side panel member 28, the frame side panel member 28 extending from the skin side panel member 26 in a direction 30 laterally relative to the skin side panel member 26. In this example, the frame side panel member 28 and the frame 16 may each be fabricated with full-size holes. This can be utilized when the shear band connector 20 is co-assembled with the fuselage skin 18, by reliably positioning the frame side panel member 28 in a predetermined connection position. The holes for connecting the frame 16 to the frame side panel member 28 can also be matched with drilled holes, drilled using a drill template or other methods, which provides a reliable and efficient connection between the frame 16 and the shear band connector 20. Method 64 further includes positioning a plurality of slots 24 spaced apart from each other along a circumferential line 32 of the fuselage body axis 22.

[0027] Method 64 further includes a plurality of shear band connectors 20. Each shear band connector 20 is positioned within one of a plurality of slots 24. Each skin side panel member 26 extends within one of the plurality of slots 24 and extends along the outer side 25 of the body axis 22. Frame side panel members 28 extend away from the outer side 25 of the body axis 22.

[0028] Method 64 further includes holding each of the plurality of shear band connectors 20 within one of the plurality of slots 24. Additionally, as Figure 5 As shown, a first composite gap filler 53 and a second composite gap filler 55 are positioned within a slot 24, wherein the first composite gap filler 53 and the second composite gap filler 55 are located between the shear band connector 20 and the fuselage body shaft 22. Positioning the first composite gap filler 53 and the second composite gap filler 55 aligned with the outer surface 38 of the fuselage body shaft 22 prevents undulations in the fuselage skin 18 caused by the curing of the first composite gap filler 53 and the second composite gap filler 55 during co-bonding of the shear band connector 20 to the fuselage skin 18. While retaining each shear band connector 20, method 64 further includes covering the skin side panel member 26 with an adhesive 56 to facilitate co-bonding the shear band connector 20 to the fuselage skin 18. As described above, an example of the fuselage skin 18 includes an tackifier (not shown) located within the fuselage skin 18, which covers the adhesive and the fuselage body shaft 22. Additionally, in this example, the composite material (not shown) is located within the fuselage skin 18 and positioned in a covering relationship relative to the tackifier. As previously mentioned, manufacturers can choose to place other materials between the composite material and the tackifier by design, where the composite material is considered to still be in a covering relationship relative to the tackifier. When the shear band connector 20 is co-bonded to the fuselage skin 18, the shear band connector 20 is secured to the fuselage skin 18 without requiring fasteners to pass through the fuselage skin 18 to secure the shear band connector 20 to the fuselage skin 18.

[0029] Although various embodiments have been described above, this disclosure is not intended to be limited thereto. Various changes can be made to the disclosed embodiments, which are still within the scope of the appended claims.

Claims

1. A shear strap connector system for securing a frame member to a composite fuselage skin, the shear strap connector system comprising: a shear strap connector, the shear strap connector comprising a skin side panel member and a frame side panel member extending from the skin side panel member; a fuselage body axis defining a slot in which the shear strap connector is positioned; as well as a first composite gap filler and a second composite gap filler positioned between the shear strap connector and the fuselage body axis, wherein the slot includes a concave surface positioned within the fuselage axis and spaced apart from an outer surface of the fuselage axis, wherein a first portion of the concave surface extends along the slot, so that when the shear strap connector is positioned in the slot, the skin side panel member of the shear strap connector extends along the first portion of the slot without extending outside the slot, wherein the slot includes a second portion of the slot extending in a direction transverse to the first portion of the slot and extending away from an outer surface of the fuselage axis, in: The second portion of the slot is defined by a pair of spaced-apart side wall portions of the fuselage axis and an end wall portion extending between the pair of spaced-apart side wall portions; and The second portion of the slot receives a frame side panel member of the shear strap connector.

2. The shear strap connector system according to claim 1, wherein: The frame side panel members extend in a direction transverse to the skin side panel members.

3. The shear strap connector system of claim 1, further comprising a plurality of slots defined by the fuselage axis, the plurality of slots being positioned spaced apart from one another.

4. The shear strap connector system according to claim 3, wherein: The plurality of slots are located along a circumferential line of the central and longitudinal axis of the fuselage.

5. The shear strap connector system according to claim 4, wherein: Each slot of the plurality of slots defines a length dimension extending along the circumferential line of the fuselage axis, the length dimension being greater than a length dimension of the shear strap connector.

6. The shear strap connector system according to claim 4, wherein: Each slot of the plurality of slots defines a width dimension extending in a direction transverse to the circumferential line of the fuselage longitudinal axis.

7. The shear strap connector system according to claim 6, wherein: The width dimension of each of the plurality of slots is greater than a width dimension of the shear strap connector.

8. The shear strap connector system of claim 1 , further comprising a retaining member positioned within the second portion of the slot, the retaining member applying a force to the frame side plate member to position the frame side plate member against one of the pair of spaced-apart side wall portions.

9. The shear strap connector system according to claim 1, further comprising: an adhesive positioned to cover the skin side panel member of the shear strap connector; a tackifier positioned to cover the adhesive; as well as A composite material is positioned in an overlying relationship relative to the tackifier.

10. A method for installing a shear strap connector system, comprising: Positioning a shear strap connector into a slot defined by a fuselage axis, wherein the shear strap connector includes a skin side panel member and a frame side panel member extending from the skin side panel member in a direction transverse to the skin side panel member; and Filling the first composite gap filler and the second composite gap filler in the narrow groove, thereby filling the gap between the shear band connector and the body axis of the fuselage, wherein the slot includes a concave surface positioned within the fuselage axis and spaced apart from an outer surface of the fuselage axis, wherein a first portion of the concave surface extends along the slot, so that when the shear strap connector is positioned within the slot, the skin side panel member extends along the first portion of the slot without extending outside the slot, wherein the slot includes a second portion of the slot extending in a direction transverse to the first portion of the slot and extending away from an outer surface of the fuselage axis, in: The second portion of the slot is defined by a pair of spaced-apart side wall portions of the fuselage axis and an end wall portion extending between the pair of spaced-apart side wall portions; and The second portion of the slot receives the frame side panel member.

11. The method of claim 10, further comprising positioning a plurality of slots spaced apart from one another along a circumferential line about the longitudinal axis of the fuselage.

12. The method of claim 11, further comprising a plurality of shear strap connectors, wherein: Each of the plurality of shear strap connectors is positioned within one of the plurality of slots; Each skin side panel member of the plurality of shear strap connectors extends within one of the plurality of slots and extends along the outboard side of the fuselage axis; and Each frame side panel member of the plurality of shear strap connectors extends away from an outboard side of the fuselage axis.

13. The method of claim 12, further comprising retaining each of the plurality of shear strap connectors within one of the plurality of slots; covering the skin side panel member with adhesive relative to the skin side panel member; covering a tackifier relative to the adhesive; as well as The composite material is covered relative to the adhesion promoter.

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