Slip Joint for Load Reduction

Abstract

To provide a sliding joint between a seat track and a flight deck floor panel for isolating and alleviating the load in an aircraft.SOLUTION: The sliding joint comprises a lug comprising a first end and a second end opposite the first end, where the first end is adapted to attach to the seat track and the second end has an elongate aperture, and a clevis comprising an oblate shaped slider bushing that is coupled to the lug.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates generally to reducing load transfer between two floor components of an aircraft, and more particularly to providing a sliding joint for separating thermal loads and bending deflections between a seat track and a flight deck floor panel during an aircraft cycle.

Background Art

[0002] In modern commercial aircraft, two or more seats are connected to an undercarriage to form a row of seats, which in turn is firmly attached to one or more longitudinally extending tracks lying beneath. Such seat tracks are connected to a floor panel of a flight deck positioned towards the front end of the aircraft. The flight deck includes, among other compartments, a lavatory and a flight cabin. Often, there is at least a few inches of vertical step at the transition between the floor slab including the seat track and the floor panel of the flight deck.

[0003] During an aircraft cycle, the movement of the aircraft causes thermal loads and body bending of the floor slab components. Thermal stresses and body bending can accumulate and be transmitted through the joints between the seat track and the flight deck floor panel. Thermal loads and bending loads often reach a magnitude sufficient to cause significant jostling to be transmitted between two sections of the aircraft. Further, these loads cause the joints to be constrained and fatigued.

[0004] An improved system and method for separating thermal loads and body bending between aircraft floor panels, such as between a passenger seat track and a flight deck floor panel, is desired.

Summary of the Invention

[0005] In one embodiment, a slip joint for separating load transfer between an aircraft seat track and a flight deck floor panel is described. The slip joint includes a lug having a first end and a second end opposite the first end. In that case, the first end is adapted to be attached to the seat track, and the second end has an elongated aperture. The slip joint further includes a clevis having an oblate shaped slider bushing coupled to the lug.

[0006] In another embodiment, an airframe structure assembly is provided. The airframe structure assembly includes a seat track, a flight deck floor panel, and a slip joint. The slip joint includes a lug having a first end and a second end opposite the first end, where the first end is adapted to be attached to the seat track and the second end has an elongated aperture, and a clevis having an oblate shaped slider bushing coupled to the lug.

[0007] In another embodiment, a method for separating load transfer between an aircraft passenger seat track and a flight deck floor panel is provided. The method includes attaching a first end of a lug to the seat track, the lug having a second end with an elongated aperture therethrough; attaching a first end of a clevis to the flight deck floor panel, the first end of the clevis having a platform from which a pair of arms extend; coupling an oblate shaped slider bushing to the pair of arms of the clevis; and receiving the oblate shaped slider bushing within the elongated aperture to secure the clevis to the lug.

[0008] The foregoing features, functions, and advantages may be individually realized in various embodiments or may be incorporated in yet another embodiment, and further details of such yet another embodiment may be understood by reference to the following description and drawings.

[0009] The characteristics of the embodiments and the novel features considered to be such are set forth in the appended claims. However, the exemplary embodiments, as well as the preferred modes of use, further objects, and their descriptions will be best understood by reading the following detailed description of the exemplary embodiments of the present disclosure with reference to the accompanying drawings.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2a

Figure 2b

Figure 2c

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0011] From here on, the examples disclosed with reference to the accompanying drawings will be described more comprehensively. The accompanying drawings show only a part, not all, of the disclosed examples. In fact, several different embodiments may be provided, and these embodiments should not be construed as being limited to the embodiments described in this specification. Rather, these embodiments are described so that this disclosure is comprehensive and complete, and so that the scope of this disclosure is fully conveyed to those skilled in the art.

[0012] Examples, methods, and systems of a slip joint for separating load transfer between an aircraft seat track and a flight deck floor panel are described. For this purpose, a lug disposed within an open channel of the seat track receives a clevis having an oval-shaped bushing and allows for back-and-forth translation of the bushing within an elongated aperture of the lug. In an example, the clevis has a platform adapted to be attached to the flight deck floor panel. The translation of the components of the slip joint assembly prevents the accumulation of thermal and bending loads between the seat track and the flight deck floor panel during an aircraft cycle while also accommodating complex geometric shape dimensions having a vertical step between two surfaces.

[0013] Further, the oval shape of the bushing provides an enlarged surface area of contact of the bushing within the elongated opening of the lug during translation. This prevents wear of the bushing itself and thus improves the life of the joint.

[0014] As used herein, a seat track may include any passenger seat track that receives one or more seat units of an aircraft. The seat unit and seat track are equipped with standard equipment used throughout the aircraft industry. In that case, the seat track includes a plurality of longitudinally spaced attachment sockets to allow the seat unit to be positioned at various positions along the seat track. The seat track is formed from a rigid material such as metal (e.g., titanium). This facilitates its ability to serve as an attachment platform for the seat unit.

[0015] As used herein, the flight deck may include the cockpit of an aircraft. From that cockpit, the pilot and crew operate the aircraft. Various equipment and control devices are positioned within the cockpit. The flight deck may further include additional spaces and compartments such as a washroom, a food preparation station, and a storage cabinet.

[0016] Referring to FIG. 1, an airframe structure assembly 100 is shown according to one embodiment, comprising a seat track 130, a floor panel 140 of the flight deck, and a slip joint 110. The slip joint 110 is disposed between the seat track 130 and the floor panel 140 of the flight deck. In FIG. 1, the airframe structure assembly within the aircraft 200 is shown.

[0017] The aircraft 200 may be a commercial aircraft used to receive and transport passengers. In that case, the passengers sit in seat units 132 attached to the seat track 130.

[0018] The floor panel 140 of the flight deck is shown in FIG. 1 as being disposed in a plane different from that of the seat track 130. In the embodiment of FIG. 1, the floor panel 140 of the flight deck is in a plane parallel to and higher than the plane in which the seat track 130 is positioned. In some embodiments, the floor panel 140 of the flight deck is positioned in a plane about 5 - 10 inches above the seat track 130. In some embodiments, the floor panel 140 of the flight deck is positioned about 7 inches above the seat track 130.

[0019] The slip joint 110 provides the main structural connection between the seat track 130 and the floor panel 140 of the flight deck. The slip joint 110 may be covered with a vertical panel or floor beam to form a step between the seat track 130 and the floor panel 140 of the flight deck. The slip joint 110 is described in more detail in FIGS. 2a - 2c and provides free translational movement back and forth. Thus, when one or both of the seat track 130 and the floor panel 140 of the flight deck are pushed against each other or otherwise experience movement during flight, certain components of the slip joint move similarly, but are separated such that the movement does not extend to the other floor panel.

[0020] FIG. 2a shows a perspective view of a slip joint, such as the slip joint 110 used within the airframe structure assembly 100 of FIG. 1, according to an exemplary embodiment.

[0021] The slip joint 110 includes a lug 112 configured to be received within an open channel 133 of a seat track, such as the seat track 130 of FIG. 1. A portion of the seat track 130 of FIG. 1 is shown in FIG. 2a. The first end 113 of the lug 112 is shown in FIG. 2a as having an engagement portion 114 for engaging the seat track 130. In FIG. 2a, the engagement portion 114 includes a plurality of apertures 115 for engaging a plurality of bolts through the plurality of apertures 115 to secure the engagement portion 114 within the seat track 130.

[0022] The second end 116 of the lug 112 has an elongated aperture 117. Within the embodiment, the elongated aperture 117 has rounded ends 118 (on both sides). Both of them are shown in the cross-sectional side view of FIG. 2b. The rounded ends 118 receive the shape of an oval-shaped slider bushing, thereby allowing the oval-shaped slider bushing to move freely end-to-end within the elongated aperture 117 without catching. The elongated aperture 117 is sized and shaped to provide a one-dimensional movement of the bushing internally. This one-dimensional movement accounts for the thermal expansion or contraction or bending deflection of the seat track 130 and the floor panel 140 of the flight deck during flight of the aircraft 200.

[0023] The slip joint 110 further includes a clevis 120. The clevis 120 includes an oblate-shaped slider bushing 122. The elongated aperture 117 of the lug 112 is sized and shaped to receive the oblate-shaped slider bushing 122. The oblate-shaped slider bushing 122 slidably secures the clevis 120 to the lug 112. The oblate-shaped slider bushing 122 is typically made of a strong material that does not wear easily, such as a metal like steel. In some embodiments, the oblate-shaped slider bushing 122 is formed from corrosion-resistant steel. In other embodiments, the oblate-shaped slider bushing 122 is formed from titanium.

[0024] Since there is contact between the oblate-shaped slider bushing 122 and the surface defining the elongated aperture 117, the outer surface of the oblate-shaped slider bushing 122 is considered a wear surface, and the oblate spheroid shape including the bushing increases the area of the wear surface of the slider bushing 122. The increased surface area of the contact of the bushing within the elongated opening of the lug during translation provided by this oblate spheroid shape prevents wear of the bushing itself and thus improves the life of the joint. The flat upper and lower surfaces 121 shown in FIG. 2c form an enlarged wear surface.

[0025] FIG. 2b shows a cross-sectional side view of the slip joint 110 of FIG. 1 coupled to the seat track 130 and the floor panel 140 of the flight deck of FIG. 1 according to an exemplary embodiment. The clevis 120 includes a platform 124 at a first end of the clevis 120 and a pair of arms 126 (only one is shown in FIG. 2b) extending from the platform 124. The oblate-shaped slider bushing 122 extends through the pair of arms 126.

[0026] As shown in FIG. 2b, the platform 124 is adapted to be attached to the floor panel 140 of the flight deck. The platform 124 may be directly attached to the floor panel of the flight deck or may be attached to a reinforcing member such as the reinforcing member 127 shown in FIG. 2b. The reinforcing member 127 may be a metal or other rigid structure that may additionally be present behind the vertical floor panel 128 to structurally support the vertical panel 128. The vertical floor panel 128 covers the step or transition gap between the seat track 130 and the floor panel 140 of the flight deck.

[0027] FIG. 2c shows a cross-sectional view of the oval-shaped slider bushing of the slip joint of FIG. 2b within the elongated aperture of the lug, according to an exemplary embodiment. The cross-section is taken along line A-A of FIG. 2b. As described above, the flat upper and lower surfaces 121 of the slider bushing 122 form an enlarged wear surface. This promotes an extended life of the bushing. The circular or rounded side surfaces 123 maintain the oblate spherical shape of the bushing and allow for smooth translational movement between the ends 118 of the elongated aperture.

[0028] The accumulation of thermal loads and body bending during the flight cycle may include 0.5 inches or more. The slip joint 110 described in detail above allows for an improved life of the joint. This is because the elongated aperture is sized and shaped to provide movement within the elongated aperture of the oval-shaped slider bushing, thereby accounting for the thermal expansion or contraction or bending deflection of the aircraft's in-flight passenger seat track and the floor panel of the flight deck. The movement includes movement in only one dimension. Thus, the life of the joint can be extended by reducing the accumulation of thermal loads and body bending applied to the joint that contribute to joint fatigue or joint restraint during the aircraft cycle.

[0029] Figure 3 shows an exemplary series of slip joints 110 disposed within an aircraft 200 according to an exemplary embodiment. As shown in Figure 3, a plurality of slip joints, such as slip joint 110 described with reference to Figures 1-2c, can be positioned across the width 170 of an aircraft, such as aircraft 200 of Figure 1, at the transition location between the seat track 130 and the flight deck floor panel 140.

[0030] Figure 4 shows a perspective enlarged view of the series of slip joints 110 of Figure 3 according to an exemplary embodiment. Figure 4 shows the reinforcement 127 and vertical panel 128 of Figure 2b, the clevis 120, and the lug 112.

[0031] Figure 5 shows a flowchart of an example of a method 500 for separating load transfer between an aircraft passenger seat track and a flight deck floor panel according to an exemplary embodiment. The method 500 shown in Figure 5 may be used, for example, in conjunction with the airframe structure assembly 100 shown in Figure 1 and / or may be performed by the airframe structure assembly 100. The method 500 includes one or more operations, functions, or tasks, such as those represented by one or more of blocks 502-508. The blocks are shown in sequence, but these blocks may also be executed in parallel and / or in an order different from the order described herein. Also, various blocks may be combined into fewer blocks, divided into additional blocks, and / or removed based on the desired implementation.

[0032] It should be understood that for this and other processes and methods disclosed herein, the flowcharts show the functions and steps of one possible embodiment of these examples. Alternative implementations are included within the scope of the examples of the present disclosure. In the examples of the present disclosure, functions may be performed in an order different from the order shown or described (including substantially simultaneously or in reverse order), depending on the relevant functionality, as would be understood by one of ordinary skill in the art.

[0033] In block 502, method 500 includes attaching a first end of the lug to the seat track. The lug further includes a second end having an elongated aperture therethrough.

[0034] The lug may be the same as or similar to lug 112, and the seat track may be similar to or the same as seat track 130 described with reference to FIGS. 1-2b. In the embodiment shown in FIGS. 2a-2b, the first end 113 of lug 112 includes an engagement portion for engaging seat track 130. Within the embodiment, the first end 113 is attached to seat track 130 by inserting the first end 113 into a channel or other opening within seat track 130. The first end 113 of lug 112 may then be fixed within seat track 130 by any one of several fasteners, such as bolts or screws, by way of non-limiting example. If seat track 130 has geometric shape dimensions different from those shown in the embodiment of FIGS. 1-2b, the first end 113 of lug 112 may be formed to conform and fit to those geometric shape dimensions.

[0035] In block 504, method 500 includes attaching a first end of the clevis to the floor panel of the flight deck. The first end of the clevis includes a platform 124 and a pair of arms extending from platform 124. Platform 124 is shown in the embodiment of FIGS. 2a-2b as having a flat surface. It may be attached directly to the panel of the flight deck or may be attached to the panel of the flight deck via components such as vertical floor beams or reinforcements positioned behind the vertical floor beams, as shown in FIG. 2b.

[0036] In block 506, method 500 includes coupling an oval-shaped slider bushing to a pair of arms of the clevis. The oval-shaped slider bushing may be the same as or similar to oval-shaped slider bushing 122 of FIGS. 2a-2c. Oval-shaped slider bushing 122 is shown as having a flat upper and lower surface 121 and circular or rounded side surfaces 123.

[0037] In block 508, method 500 includes receiving an oval-shaped slider bushing within an elongated aperture to secure the clevis to the lug. The elongated aperture 117 at the second end 116 of the lug 112 has a rounded end 118 in the illustrated embodiment of FIGS. 2a-2b, and receives the shape of the oval-shaped slider bushing, thereby enabling the oval-shaped slider bushing to move end-to-end within the elongated aperture 117.

[0038] Within an embodiment, movement of the floor panel 140 of the flight deck will move the clevis 120 and associated oval-shaped slider bushing 122 back and forth within the elongated aperture 117. In a further embodiment, movement of the seat track 130 will move the lug back and forth.

[0039] FIG. 6 shows another method used in conjunction with method 500 shown in FIG. 5, according to an exemplary embodiment. In block 510, the method includes translating an oval-shaped slider bushing back and forth within an elongated aperture during an aircraft cycle. When the aircraft 200 takes off and then proceeds to flight in the air, one or both of the seat track 130 and the flight deck panel 140 may move or push against each other. Such movement moves the slider bushing 122 back and forth in either direction within the elongated aperture 117.

[0040] Within an embodiment, the translation of the components of the slip joint assembly prevents the accumulation of thermal and bending loads between the seat track and the flight deck floor panel during an aircraft cycle while accommodating complex geometric shape dimensions between the seat track and the flight deck floor panel. The oval shape of the bushing provides an increased surface area of contact of the bushing within the elongated opening of the lug during translation. It prevents wear of the bushing itself and thus improves the life of the joint.

[0041] The descriptions of various advantageous configurations are presented for purposes of illustration and description and are not intended to be exhaustive or to limit the embodiments to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. Further, various advantageous embodiments may represent different advantages compared to other advantageous embodiments. The selected one or more embodiments are selected and described to well illustrate the principles of the embodiments, the practical applications, and to facilitate understanding by other persons of ordinary skill in the art of the disclosure of the various embodiments and the various modifications suitable for the particular applications being considered.

[0042] Clause 1. A slip joint for separating load transfer between an aircraft seat track and a flight deck floor panel, the slip joint comprising a lug having a first end and a second end opposite the first end, the first end being adapted to be attached to the seat track, the second end having an elongated aperture, the lug, and a clevis coupled to the lug and comprising an eccentrically shaped slider bushing. Clause 2. The elongated aperture of the lug is sized and shaped to receive the eccentrically shaped slider bushing so as to slidably secure the clevis to the lug, the slip joint according to Clause 1. Clause 3. The elongated aperture has rounded ends, the slip joint according to Clause 2. Clause 4. The first end of the lug comprises an engagement portion for engaging the seat track, the slip joint according to any one of Clauses 1 to 3. Clause 5. The clevis comprises a platform at a first end of the clevis and a pair of arms extending from the platform, the slip joint according to any one of Clauses 1 to 4. Clause 6. The eccentrically shaped slider bushing extends through the pair of arms, the slip joint according to Clause 5. Clause 7. The offset circular-shaped slider bushing has an offset spherical shape, thereby increasing the area of the wear surface of the offset circular-shaped slider bushing, the slip joint according to clause 6. Clause 8. The platform of the clevis is adapted to be attached to the floor panel of the flight deck, the slip joint according to any one of clauses 1 to 7. Clause 9. The elongated aperture is sized and shaped to provide a one-dimensional movement of the offset circular-shaped slider bushing within the elongated aperture, thereby taking into account thermal expansion or contraction or bending deflection of the seat track and the floor panel of the flight deck during flight of the aircraft, the slip joint according to any one of clauses 1 to 8. Clause 10. The one-dimensional movement includes a back-and-forth translational movement of the offset circular-shaped slider bushing within the elongated aperture, the slip joint according to clause 9. Clause 11. An airframe structure assembly comprising a seat track, a floor panel of a flight deck, and a slip joint, the slip joint being a lug defining a first end and a second end opposite the first end, the second end having an elongated aperture, the lug, and a clevis comprising an offset circular-shaped slider bushing coupled to the lug. Clause 12. The first end of the lug is attached to the seat track, the airframe structure assembly according to clause 11. Clause 13. The clevis comprises a first end having a platform and a pair of arms extending from the platform, the first end being attached to the floor panel of the flight deck, the airframe structure assembly according to clause 12. Clause 14. The offset circular-shaped slider bushing is coupled between and extends between the pair of arms, the offset circular-shaped slider bushing being received within the elongated aperture of the lug, the airframe structure assembly according to clause 13. Clause 15. The elongated aperture is sized and shaped to provide movement within the elongated aperture of the oval-shaped slider bushing, thereby accounting for thermal expansion or contraction or bending deflection of the seat track and the floor panel of the flight deck during flight of the aircraft, the airframe structure assembly according to clause 14. Clause 16. The movement includes only one-dimensional movement, the airframe structure assembly according to clause 15. Clause 17. The movement includes back-and-forth parallel movement of the oval-shaped slider bushing within the elongated aperture, the airframe structure assembly according to clause 16. Clause 18. The oval-shaped slider bushing has an aspherical shape, the airframe structure assembly according to any one of clauses 11 to 17. Clause 19. A method for separating load transfer between an aircraft passenger seat track and a floor panel of a flight deck, comprising attaching a first end of a lug to the passenger seat track, the lug further comprising a second end having an elongated aperture therethrough; attaching a first end of a clevis to the floor panel of the flight deck, the first end of the clevis comprising a platform from which a pair of arms extend; coupling an oval-shaped slider bushing to the pair of arms of the clevis; and receiving the oval-shaped slider bushing within the elongated aperture to secure the clevis to the lug. Clause 20. The method according to clause 19, further comprising moving the oval-shaped slider bushing back and forth in a parallel direction within the elongated aperture during a cycle of the aircraft.

Claims

1. A slip joint for separating load transfer between an aircraft seat track and a flight deck floor panel, comprising: A lug having a first end and a second end opposite the first end, the first end being adapted to be attached to the seat track, the second end having an elongated aperture, the lug, and A clevis having an eccentrically shaped slider bushing coupled to the second end of the lug, the first end of the clevis being adapted to be attached to the flight deck floor panel, the clevis Comprising a slip joint.

2. The slip joint according to claim 1, wherein the elongated aperture of the lug is sized and shaped to receive the eccentrically shaped slider bushing so as to slidably secure the clevis to the lug.

3. The slip joint according to claim 2, wherein the elongated aperture has rounded ends.

4. The slip joint according to any one of claims 1 to 3, wherein the first end of the lug comprises an engaging portion for engaging the seat track.

5. The slip joint according to any one of claims 1 to 4, wherein the clevis comprises a platform at the first end of the clevis and a pair of arms extending from the platform.

6. The slip joint according to claim 5, wherein the eccentrically shaped slider bushing extends through the pair of arms.

7. The slip joint according to claim 6, wherein the eccentrically shaped slider bushing has an eccentric spherical shape, thereby increasing the area of the wear surface of the eccentrically shaped slider bushing.

8. The slip joint according to any one of claims 5 to 7, wherein the pair of arms extends in a direction different from the extending direction of the elongated aperture, and the platform of the clevis is adapted to be attached to the flight deck floor panel at a height different from the seat track.

9. The slip joint according to any one of claims 1 to 8, wherein the elongated aperture is sized and shaped to provide a one-dimensional movement of the eccentrically shaped slider bushing within the elongated aperture, thereby taking into account thermal expansion or contraction or bending deflection of the seat track and the flight deck floor panel during flight of the aircraft.

10. The one-dimensional movement includes a back-and-forth parallel movement of the elliptical slider bush within the elongated aperture, the slip joint according to claim 9.

11. A seat track, a floor panel of a flight deck, and an airframe structure assembly comprising a slip joint, wherein the slip joint comprises a lug defining a first end and a second end opposite the first end, the first end being attached to the seat track, the second end having an elongated aperture, the lug, and a clevis comprising an elliptical slider bush coupled to the second end of the lug, a first end of the clevis being attached to the floor panel of the flight deck, the clevis An airframe structure assembly comprising.

12. The clevis comprises a platform at the first end of the clevis and a pair of arms extending from the platform, the first end being attached to the floor panel of the flight deck, the airframe structure assembly according to claim 11.

13. The elliptical slider bush is coupled between and extends between the pair of arms, the elliptical slider bush being received within the elongated aperture of the lug, the airframe structure assembly according to claim 12.

14. The elongated aperture is sized and shaped to provide movement of the elliptical slider bush within the elongated aperture, thereby accounting for thermal expansion or contraction or bending deflection of the seat track and the floor panel of the flight deck during flight of the aircraft, the airframe structure assembly according to claim 13.

15. The movement includes only one-dimensional movement, the airframe structure assembly according to claim 14.

16. The movement includes a back-and-forth parallel movement of the elliptical slider bush within the elongated aperture, the airframe structure assembly according to claim 15.

17. The pair of arms extends in a direction different from the extending direction of the elongated aperture, and the platform of the clevis is attached to the floor panel of the flight deck at a height different from the seat track, the airframe structure assembly according to any one of claims 12 to 16.

18. The elliptical slider bush has an ellipsoidal shape, the airframe structure assembly according to any one of claims 11 to 17.

19. A method for separating load transfer between an aircraft passenger seat track and a flight deck floor panel, comprising: attaching a first end of a lug to the aircraft passenger seat track, the lug further comprising a second end having an elongated aperture therethrough; attaching a first end of a clevis to the flight deck floor panel, the first end of the clevis comprising a platform from which a pair of arms extend; coupling an oval-shaped slider bushing to the pair of arms of the clevis; and receiving the oval-shaped slider bushing within the elongated aperture to secure the clevis to the lug. **Claim 20** The method of claim 19, further comprising translating the oval-shaped slider bushing back and forth within the elongated aperture during an aircraft cycle.

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