Serrated fitting

Abstract

To provide a serrated fitting and method for installing fixed-length roller tray segments spanning an aircraft fuselage integration zone.SOLUTION: A serrated fitting 806 includes a first surface 820 for attachment to a fixed-length roller tray segment 802. The serrated fitting also includes a serrated surface for engagement with a serrated plate 828 attached to a floor beam 804 of an aircraft. A fastener connects the serrated surface to the serrated plate and the floor beam through a pre-drilled hole in the floor beam. The pre-drilled hole is larger than the diameter of the fastener 836, 837 to accommodate accumulated tolerance between joined fuselage sections at a fuselage integration zone.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001]

[0001] The present disclosure relates generally to a sawtooth attachment and, more particularly, to a no-drill solution for supporting installation of fixed-length roller tray segments of a cargo handling system across fuselage integration zones having large manufacturing tolerances. [Background technology]

[0002]

[0002] Cargo aircraft often incorporate continuous roller trays for cargo handling. The roller trays are made up of multiple segments, each of which has a fixed length. In some cases, the roller tray segments cross over fuselage sections that have circumferential joints. The circumferential joints may also be referred to as integration zones. Integration zones are locations where two adjacent fuselage sections are joined. At these locations, assembly tolerances are accumulated.

[0003]

[0003] The installation of a continuous roller tray loading system utilizes discrete roller tray attachments at each end or along the length of a fixed length roller tray segment that is fastened to pre-installed floor beams. In the fuselage integration zone, the exact distance between the floor beams is unknown because of the assembly tolerances that accumulate between the fuselage sections.

[0004] To accommodate these assembly tolerances, existing solutions delay installation (i.e., drilling and filling) of roller tray attachments to floor beams until after the circumferential joints are installed on the airplane during final assembly. Aircraft manufacturers drill holes into the aircraft undercarriage, such as floor beams, to attach fixed-length roller tray segments during final assembly after the fuselage circumferential joints are assembled. This post-final assembly drilling in the floor beams presents a significant foreign object debris (FOD) and cost issue if any systems, such as electrical, fuel, or environmental control (ECS), were previously installed in the fuselage below the drilling location.

[0005]

[0005] It would therefore be desirable to have a method and apparatus that takes into account at least some of the problems discussed above, as well as other possible problems. Summary of the Invention

[0006] An exemplary embodiment of the present disclosure provides a sawtooth attachment for installation of a fixed length roller tray segment on an aircraft. The sawtooth attachment includes a first surface and a sawtooth surface opposite the first surface. The first surface is connected to the fixed length roller tray segment. The sawtooth surface is for engaging a sawtooth plate attached to a floor beam pre-installed in the aircraft. A fastener passes through a pre-drilled hole in the floor beam to connect the sawtooth surface to the sawtooth plate and floor beam. The pre-drilled hole has a dimension axially aligned with a longitudinal axis of the fixed length roller tray segment. The dimension is greater than a diameter of the fastener.

[0007]

[0007] An exemplary embodiment of the present disclosure provides a fixed length roller tray installation system including an aircraft fixed length roller tray segment, a sawtooth attachment, a sawtooth plate, and a fastener. The sawtooth attachment is connected to the fixed length roller tray segment. The sawtooth plate is connected to an aircraft floor beam. The sawtooth surface of the sawtooth attachment engages with the sawtooth plate. The fastener passes through a pre-drilled hole in the floor beam to connect the sawtooth surface of the sawtooth attachment to the sawtooth plate and to the aircraft floor beam.

[0008]

[0008] A further exemplary embodiment of the present disclosure provides a method for installing fixed length roller tray segments spanning an aircraft fuselage integration zone. A first set of floor beams is installed in a first aircraft fuselage section. A second set of floor beams is installed in a second aircraft fuselage section, where at least one of the first set of floor beams or the second set of floor beams includes pre-drilled holes. The first aircraft fuselage section is joined to the second aircraft fuselage section at the fuselage integration zone. A sawtooth attachment is connected to the fixed length roller tray segments. A sawtooth plate is connected to the first set of floor beams or the second set of floor beams with pre-drilled holes. The sawtooth plate surrounds the pre-drilled holes. A sawtooth surface of the sawtooth attachment engages the sawtooth plate. The sawtooth attachment is secured to the first set of floor joists or the second set of floor joists with fasteners that pass through pre-drilled holes having a dimension axially aligned with the longitudinal axis of the fixed length roller tray segment and a dimension larger than a diameter of the fasteners.

[0009]

[0009] These features and functions may be realized individually in various embodiments of the present disclosure or may be combined in further embodiments, further details of which can be understood with reference to the following description and drawings.

[0010]

[0010] The novel features believed characteristic of the illustrative embodiments are set forth in the appended claims. However, the illustrative embodiments as well as the preferred modes of use, further objects and features thereof will be best understood by reading the following detailed description of the illustrative embodiments of the present disclosure in conjunction with the accompanying drawings. [Brief description of the drawings]

[0011] [Figure 1]

[0011] FIG. 1 is an illustration of an aircraft in accordance with an exemplary embodiment. [Diagram 2]

[0012] FIG. 1 is a block diagram of a manufacturing environment in accordance with an illustrative embodiment. [Diagram 3]

[0013] FIG. 1 is an illustration of a load handling system in accordance with an illustrative embodiment. [Figure 4]

[0014] FIG. 1 is an illustration of a load handling system in accordance with an illustrative embodiment. [Diagram 5]

[0015] FIG. 1 illustrates a fixed length roller tray mounting system according to an exemplary embodiment. [Figure 6]

[0016] FIG. 1 illustrates an exploded view of a fixed length roller tray mounting system according to an exemplary embodiment. [Figure 7]

[0017] FIG. 1 is a perspective view of a sawtooth fixture and a sawtooth plate according to an illustrative embodiment; [Figure 8]

[0018] FIG. 1 illustrates a fixed length roller tray mounting system according to an exemplary embodiment. [Figure 9]

[0019] 1 is an illustration of a flowchart of a process for installing fixed length roller tray segments spanning an aircraft fuselage integration zone in accordance with an illustrative embodiment; [Figure 10]

[0020] FIG. 1 is a block diagram of an aircraft manufacturing and service method in accordance with an illustrative embodiment. [Figure 11]

[0021] FIG. 1 is a block diagram of an aircraft in which an illustrative embodiment may be implemented. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012]

[0022] The illustrative embodiments recognize and take into account one or more various assumptions. For example, the illustrative embodiments recognize and take into account that a continuous roller tray handling system installation utilizes discrete, fixed-length roller tray segments.

[0013]

[0023] The illustrative embodiments also recognize and take into account that the installation of a fixed length roller tray segment may span a circumferential joint or merge zone of two joined fuselage sections. Due to manufacturing variations, the spacing between the floor beams of the two joined fuselage sections may not be consistent and will vary within a tolerance range.

[0014]

[0024] The illustrative embodiments also recognize and take into account that because the exact distance between floor beams may not be known prior to joining the fuselage sections, existing installation techniques attach fixtures to the floor beams after the circumferential joints are installed on the aircraft during final assembly, which requires the aircraft manufacturer to drill holes into the aircraft structure during final assembly to attach the fixed length roller tray segments.

[0015]

[0025] The illustrative embodiments also recognize and take into account that this post-final assembly drilling in the floor beam is a significant FOD issue to any systems, such as electrical, fuel, or ECS, previously installed in the fuselage below the drilling location.

[0016]

[0026] Thus, exemplary embodiments provide a sawtooth attachment for installation of fixed length roller tray segments across a fuselage integration zone in final assembly. The engagement of the sawtooth plate and oversized pre-drilled holes allows for drill-free installation of the fixed length roller tray segments and their respective sawtooth attachments within a fuselage circumferential integration zone having floor beam to floor beam distance variations. The load path of the fixed length roller tray segments passes through the sawtooth attachments, bypassing fasteners used to attach the sawtooth attachments and ultimately the fixed length roller tray segments to the aircraft floor beams, while also accounting for tolerance stack-up between joined fuselage sections at the fuselage integration zone.

[0017]

[0027] 1 , a diagram of an aircraft is shown in accordance with an illustrative embodiment. In this illustrative embodiment, aircraft 100 has wings 102 and 104 attached to fuselage 106. Aircraft 100 includes engines 108 and 110 attached to wing 102 and wing 104.

[0018]

[0028] The fuselage 106 has an empennage 112. A horizontal stabilizer 114, a horizontal stabilizer 116, and a vertical stabilizer 118 are attached to the empennage 112 of the fuselage 106.

[0019]

[0029] Aircraft 100 is an example of an aircraft in which a fixed length roller tray of a cargo handling system may be installed according to an illustrative embodiment. For example, a cargo area located within fuselage 106 of aircraft 100 may have a cargo handling system attached to floor beams of the aircraft. Fixed length roller tray segments of the cargo handling system may be attached to floor beams after the fuselage sections are joined, where the fixed length roller tray segments span the fuselage integration zones of the joined fuselage sections. A fixed length roller tray installation system with sawtooth attachments allows the fixed length roller tray to be attached to the floor beams in place to account for tolerances between the joined fuselage sections.

[0020]

[0030] The illustration of aircraft 100 in Figure 1 is not meant to imply physical or architectural limitations to the manner in which an illustrative embodiment may be implemented. For example, aircraft 100 is a civilian aircraft, but aircraft 100 may also be a military aircraft, a rotorcraft, a helicopter, an unmanned aerial vehicle, or any other suitable aircraft.

[0021]

[0031] Although exemplary embodiments are described with respect to an aircraft, an exemplary embodiment may be applied to other types of platforms. The platform may be, for example, a mobile platform, a fixed platform, a land structure, a water structure, or a space structure. More specifically, the platform may be an aircraft, a surface ship, a tank, a personnel carrier, a train, a spacecraft, a space station, a satellite, a submarine, an automobile, a power plant, a bridge, a dam, a house, a manufacturing facility, a building, a tool, a machine structure, or some other suitable platform or structure where installation of fixed-length roller tray segments is desired.

[0022]

[0032] With reference now to Figure 2, a block diagram of an aircraft manufacturing environment is shown in accordance with an illustrative embodiment. Aircraft manufacturing environment 200 includes an aircraft 202 and a fixed length roller tray installation system 204.

[0023]

[0033] In this illustrative example, aircraft 202 includes first fuselage section 206 and second fuselage section 208. First fuselage section 206 is joined with second fuselage section 208 at fuselage integration zone 210. First fuselage section 206 includes first set of floor beams 212 and second fuselage section 208 includes second set of floor beams 214. In this illustrative example, aircraft 202 is in final assembly where first fuselage section 206 is joined with second fuselage section 208. The distance between a floor beam in first set of floor beams 212 and a floor beam in second set of floor beams 214 is unknown prior to final assembly due to tolerances within fuselage integration zone 210. Floor beam 220 represents either a floor beam in first set of floor beams 212 or second set of floor beams 214. The floor beam 220 includes pre-drilled holes 222. The pre-drilled holes 222 are drilled into the floor beam 220 prior to final assembly or before the first fuselage section 206 is joined to the second fuselage section 208. Pre-drilling the pre-drilled holes 222 prior to joining the first fuselage section 206 with the second fuselage section 208 prevents foreign debris, such as drill shavings, from interfering with any systems already installed within the fuselage. In other words, holes are not drilled into the floor beam after the fuselage sections are joined together. The pre-drilled holes 222 are present before the fuselage sections are joined together in final assembly.

[0024]

[0034] The pre-drilled holes 222 have a dimension 224. The dimension 224 is a front-to-rear dimension and must be larger than the diameter of the fasteners that will be used in the pre-drilled holes 222. The pre-drilled holes 222 are typically circular or slot shaped, but can be any shape including a dimension larger than the diameter of the fasteners. In other words, the dimension 224 of the pre-drilled holes 222 must be of sufficient size to account for manufacturing and assembly tolerances that may be applicable. The dimension 224 is axially aligned or parallel to the longitudinal axis of the fixed length roller tray segment 230 that will soon be attached. The dimension 224 is axially aligned or parallel to the longitudinal axis of the fuselage section. The dimension 224 accounts for variations in the distance between the floor joists to which the fixed length roller tray segments will be attached. Dimension 224 is large enough to accommodate longitudinal stacking tolerances in fuselage integration zone 210 between first fuselage section 206 and second fuselage section 208. Dimension 224 allows for adjustment of the fore-to-aft position of the fixed length roller tray segments relative to the floor beams.

[0025]

[0035] As used herein, the term "set" when used in reference to a plurality of items means one or more items. For example, a "set" of floor joists is one or more of floor joists 220.

[0026]

[0036] As used herein, the phrase "at least one of" used in conjunction with enumerated items means that various combinations of one or more of the enumerated items may be used and that only one of each enumerated item may be required. In other words, "at least one of" means that any combination of items and any number of items from the enumeration may be used, and not all of the enumerated items are required. An item may be a specific object, article, or category.

[0027]

[0037] For example, without limitation, "at least one of item A, item B, and item C" may include item A, item A and item B, or item B. This example may also include item A, item B, and item C, or item B and item C. Of course, any combination of these items may be present. In some illustrative examples, "at least one of" may be, by way of example and not limitation, "two item A, one item B, and ten item C," "four item B, and seven item C," or any other suitable combination.

[0028]

[0038] As used herein, a first component is "connected" or "coupled" or "associated" with a second component means that the first component can be directly or indirectly connected to the second component. A connection is a physical association. In other words, there may be an additional component between the first component and the second component. A first component is considered to be indirectly connected to a second component when there is one or more additional components between the two components. When a first component is directly connected to a second component, there is no additional component between the two components.

[0029]

[0039] For example, a first component may be considered to be physically connected to a second component by at least one of being fixed to the second component, glued to the second component, attached to the second component, welded to the second component, fastened to the second component, or connected to the second component in some other suitable manner. The first component may also be connected to the second component using a third component. The first component may also be physically connected to the second component by being formed as part of the second component, as an extension of the second component, or both.

[0030]

[0040] In this exemplary embodiment, fixed length roller tray installation system 204 includes a fixed length roller tray segment 230 , a sawtooth attachment 232 , a sawtooth plate 234 , and a fastener 236 .

[0031]

[0041] The fixed length roller tray segment 230 is one segment of a complete cargo handling system installed within the cargo hold of the aircraft 202. The fixed length roller tray segment 230 may span the fuselage integration zone 210, but does not necessarily have to. The fixed length roller tray segment 230 has a longitudinal axis 240. The longitudinal axis 240 is axially aligned with the longitudinal directions of the first fuselage section 206 and the second fuselage section 208. Although one fixed length roller tray segment 230 is shown, the fixed length roller tray installation system 204 may have two or more fixed length roller tray segments 230 for installation with the sawtooth attachment 232. For example, the fixed length roller tray installation system 204 may include any number of fixed length roller tray segments installed across the floor of the cargo area of ​​the aircraft.

[0032]

[0042] The fixed length roller tray segment 230 of the cargo handling system installed in the cargo hold of the aircraft 202 has a load path 242. The load path 242 is a result of the movement of cargo loaded into the cargo handling system during operation of the aircraft 202. Front-to-aft and / or side-to-side forces generated by the cargo movement are transferred from the fixed length roller tray segment of the cargo handling system via the load path 242 to the floor beams of the aircraft.

[0033]

[0043] Load path 242 represents front-to-back and / or side-to-side loads resulting from the movement of cargo supported by the cargo handling system. Vertical tensile loads, such as when an aircraft is diving, are not represented by the illustrated load path 242. Load path 242 begins within fixed length roller tray segment 230. Through the use of sawtooth attachments 232, load path 242 is directed from fixed length roller tray segment 230 through sawtooth attachments 232 and sawtooth plate 234 to the floor beam, which is the floor beam to which fixed length roller tray segment 230 is attached (such as floor beam 220). Load path 242 does not pass through fasteners 236 used to attach sawtooth attachments 232 and ultimately fixed length roller tray segment 230 to a floor beam, such as floor beam 220.

[0034]

[0044] The sawtooth attachment 232 includes a first surface 244. The first surface 244 defines an overhang 246. The sawtooth attachment 232 is connected to the fixed length roller tray segment 230 at the first surface 244 with a fastener 248 that cooperates with the overhang 246. The fastener 248 may be any type of fastener including, for example, a tension stud. Other structural arrangements are possible without the overhang and tension stud combination, so long as the first surface 244 includes a surface area the minimum of which has a size sufficient to carry the load expected to come from the cargo supported by the material handling system.

[0035]

[0045] The sawtooth fitting 232 includes a sawtooth surface 250. The sawtooth surface 250 is on an opposite side of the sawtooth fitting 232 from the first surface 244. The sawtooth surface 250 has a surface area 252. The 2D shape of the sawtooth surface 250 is generally polygonal, but may be circular, oval, or other shapes, so long as a majority of the surface area 252 is available for engagement with the sawtooth plate 234. A majority is defined in an exemplary sense, meaning at least more than half of the surface area 252, e.g., at least 51% to 100% of the surface area 252, is available for engagement with the sawtooth plate 234. The surface area 252 is designed to meet load transfer requirements from the cargo being supported by the load handling system.

[0036]

[0046] The sawtooth plate 234 is connected to the floor joist 220. The sawtooth plate 234 is connected to the floor joist 220 prior to final assembly, in other words, the sawtooth plate 234 is pre-attached to the floor joist 220 prior to final assembly. The sawtooth plate 234 may be connected to the floor joist 220 with fasteners that are not common to the fixed length roller tray segments 230, for example, or the sawtooth plate 234 may be connected to the floor joist 220 with an adhesive. The sawtooth plate 234 may be integrally formed with the floor joist 220. The sawtooth plate 234 includes a pre-drilled hole 254. The pre-drilled hole 254 has a dimension 256. The size and shape of the pre-drilled hole 254 and the dimension 256 generally match the pre-drilled hole 222 and the dimension 224 in the floor joist 220. The pre-drilled holes 254 are typically circular or slot shaped, but can be any shape, including a dimension larger than the diameter of the fasteners 236. In other words, the dimension 256 of the pre-drilled holes 254 must be of sufficient size to account for manufacturing and assembly tolerances that may be applicable. The serrated plate 234 is connected to the floor joists 220. In that case, the pre-drilled holes 254 align with the pre-drilled holes 222.

[0037]

[0047] Fastener 236 connects sawtooth attachment 232 to sawtooth plate 234. Fastener 236 has a diameter 258. Diameter 258 is appreciably smaller than dimension 256 and dimension 224. If fastener 236 has a typical non-circular cross-section, the maximum dimension of the non-circular cross-section must be appreciably smaller than dimension 256 and dimension 224. In other words, there is a clearance fit between fastener 236 and pre-drilled hole 222 and pre-drilled hole 254 in the directions of dimensions 224 and 256, respectively. This allows fastener 236 to be inserted into pre-drilled hole 222 and pre-drilled hole 254 without interference from floor joist 220 and sawtooth plate 234.

[0038]

[0048] The serrations of the serrated surface 250 of the sawtooth attachment 232 engage the serrations of the sawtooth plate 234. The engagement of the serrations prevents front-to-back movement of the sawtooth attachment 232 relative to the sawtooth plate 234 in the direction of dimension 256 or dimension 224. The engagement of the serrations also helps prevent side-to-side movement of the sawtooth attachment 232 relative to the sawtooth plate 234. The positioning of the sawtooth attachment 232 relative to the sawtooth plate 234 is adjustable because the diameter 258 is smaller than the dimension 256 and the dimension 224. The adjustable positioning of the sawtooth attachment 232 relative to the sawtooth plate 234 through the length of the dimension 256 and the dimension 224 is a way in which one exemplary embodiment of the fixed length roller tray mounting system 204 accommodates manufacturing variations resulting from the spacing between the floor beams of two joined fuselage sections that may not be consistent.

[0039]

[0049] 3-4, diagrams of a load handling system according to an exemplary embodiment are shown. In this and the following exemplary examples, the same reference numbers may be used in the figures. Such repeated reference numbers in different figures represent the same elements in such different figures. The components shown in FIGS. 3-4 are examples of physical implementations of the first fuselage section 206, the second fuselage section 208, the fuselage integration zone 210, the first set of floor beams 212, the second set of floor beams 214, and the floor beams 220, which are shown in block form in FIG. 2.

[0040]

[0050] As shown, the load handling system 300 includes fixed length roller tray segments 320, 322 attached to a first set of floor beams 312 in a first fuselage section 302 and fixed length roller tray segments 324, 326 attached to a second set of floor beams 314 in a second fuselage section 304. A sawtooth attachment 310 or a standard attachment is disposed between each fixed length roller tray segment and the corresponding floor beam. In this illustrated embodiment, a standard attachment, i.e., an attachment not subject to this disclosure, could be used in place of the sawtooth attachment 310 because the fixed length roller tray segments 320, 322, 324, 326 do not span the fuselage integration zone. However, the sawtooth attachment 310 could be used in this situation as well. The sawtooth attachment 310 could be used at each end or along the length of any fixed length roller tray segment. In other words, the sawtooth fixture 310 can be used at any floor joist location where a tolerance stackup exists.

[0041]

[0051] A first fuselage section 302 is ready to be joined to a second fuselage section 304 in final assembly. A first set of floor beams 312 are pre-installed in the first fuselage section 302 prior to final assembly. A second set of floor beams 314 are pre-installed in the second fuselage section 304 prior to final assembly. The distance 306 between floor beams 316 of the first fuselage section 302 and floor beams 318 of the second fuselage section 304 is not known until after final assembly because there are allowable manufacturing tolerances 308.

[0042]

[0052] As shown in FIG. 4, when the first fuselage section 302 is joined to the second fuselage section 304, the fixed length roller tray segment 402 is connected to and between the floor beams 316 and 318. The sawtooth fittings 404 and 406 connect the fixed length roller tray segment 402 to the floor beams 316 and 318, respectively. The sawtooth fittings 404 and 406 are placed in pre-drilled holes in the floor beams 316, 318. The length of the dimension of the pre-drilled holes in the longitudinal direction 410 allows for lateral (as viewed in the figure) movement of the fittings relative to the floor beams to accommodate manufacturing tolerances 308 in final assembly. In a minimal implementation scenario, only one fitting, either the sawtooth fitting 404 or the sawtooth fitting 406, is required. Factors considered in determining whether one or two fixtures are used include excess integration tolerances allowed for by having adjustability at both ends of the fixed length roller tray segment 402, commonality for maintenance, assembly costs, etc.

[0043]

[0053] 5-7, a diagram of a fixed length roller tray installation system 500 is shown according to one exemplary embodiment.

[0044]

[0054] Figure 5 is an expanded view of inset 408 of Figure 4. As shown, fixed length roller tray segment 502 is attached to floor beam 504 via sawtooth fitting 506 after final assembly. Fixed length roller tray segment 510 is pre-attached to floor beam 504 via fitting 512 prior to final assembly. Fitting 512 may be considered an example of a standard fitting (not the subject of this disclosure).

[0045]

[0055] A first surface 520 of the sawtooth attachment 506 is connected to the fixed length roller tray segment 502 via a fastener 522 engaged with an overhang 524. The fastener 522 may be any type of fastener including, for example, a tension stud. Other structural arrangements are possible without the combination of overhang 524 and fastener 522, so long as the first surface 520 includes a surface area the minimum area of ​​which has a size sufficient to carry the load expected to come from the cargo supported by the material handling system. The sawtooth attachment 506 includes a sawtooth surface 526.

[0046]

[0056] The sawtooth plate 528 is connected to the floor joist 504. The sawtooth plate 528 is pre-attached to the floor joist 504 prior to final assembly. The sawtooth plate 528 may be connected to the floor joist 504 with fasteners 546, 548. Alternatively, in non-limiting examples, the sawtooth plate 528 may be connected to the floor joist 504 with an adhesive or may be integrally formed with the floor joist 504. The sawtooth plate 528 includes a pre-drilled hole 530. The pre-drilled hole 530 has a dimension 532. The size and shape of the pre-drilled hole 530 and the dimension 532 generally match the pre-drilled hole 540 and the dimension 542 in the floor joist 504.

[0047]

[0057] Fastener 536 connects sawtooth fitting 506 to sawtooth plate 528. Fastener 536 has a diameter 538. Diameter 538 is appreciably smaller than dimensions 532 and 542 to allow for placement of fastener 536 along the length of dimensions 532 and 542.

[0048]

[0058] The serrations of the sawtooth surface 526 engage with the sawtooth plate 528. The engagement of the sawtooth prevents front-to-back movement of the sawtooth attachment 506 in the direction 534 relative to the sawtooth plate 528. The engagement of the sawtooth also helps prevent side-to-side movement of the sawtooth attachment 506 relative to the sawtooth plate 528. The positioning of the sawtooth attachment 506 relative to the sawtooth plate 528 is adjustable because the diameter 538 is smaller than the dimensions 532 and 542. The adjustable positioning of the sawtooth attachment 506 relative to the sawtooth plate 528 through the length of the dimensions 532 and 542 accommodates manufacturing variations resulting from the spacing between the floor beams 316, 318 of the two joined fuselage sections 302, 304 in final assembly, which may vary at each fuselage integration zone.

[0049]

[0059] The sawtooth fitting 506 may be referred to as a split fitting or a roller tray end fitting. The split fitting works in conjunction with a standard fitting such as fitting 512. Fitting 512 connects fixed length roller tray segment 510 to floor beam 504. Fixed length roller tray segment 510 does not span the fuselage integration zone. The sawtooth fitting 506 connects fixed length roller tray segment 502 to floor beam 504. Fixed length roller tray segment 502 would then span the fuselage integration zone. The sawtooth fitting 506 accommodates the tolerance stack-up between joined fuselage sections at the fuselage integration zone.

[0050]

[0060] The load path 544 of the fixture 512 is shown passing through the fasteners connecting the fixture 512 to the floor joists 504. The path of the load path 544 passes through the fasteners because the fasteners are an interference fit with the floor joists and, because they have no sawtooth, the fasteners are the only obstacle to movement between the fixture and the floor joists.

[0051]

[0061] In contrast, the load path 550 of the fixed length roller tray mounting system 500 passes through the sawtooth fittings 506 and bypasses the fasteners 536. The engagement of the serrations of the sawtooth surface 526 with the serrations of the sawtooth plate 528 provides the load path 550.

[0052]

[0062] Load path 550 represents front-to-back and / or side-to-side loads resulting from the movement of cargo supported by the load handling system. Vertical tensile loads, such as when an aircraft is diving, are not represented by the illustrated load path 550. Load path 550 begins within fixed length roller tray segment 502. Through the use of sawtooth attachments 506, load path 550 is directed from fixed length roller tray segment 502 through sawtooth attachments 506 and sawtooth plate 528 to floor beam 504. Load path 550 does not pass through fasteners 536 used to attach sawtooth attachments 506 and ultimately fixed length roller tray segment 502 to floor beam 504.

[0053]

[0063] Referring now to FIG. 8, a fixed length roller tray installation system 800 is shown according to one exemplary embodiment.

[0054]

[0064] As shown, the fixed length roller tray segment 802 is attached to the floor beam 804 via a sawtooth fitting 806 after final assembly. The sawtooth fitting 806 may be referred to as a one-piece fitting or an intermediate fitting. The fixed length roller tray segment 802 may or may not span the fuselage integration zone. The sawtooth fitting 806 replaces the fitting 512 shown in Figures 5-7, doubling the surface area of ​​the sawtooth fitting 506. Certain elements of the sawtooth fitting 806 function in a similar manner to elements of the sawtooth fitting 506 previously described, although some elements may overlap.

[0055]

[0065] A first surface 820 of the sawtooth attachment 806 is connected to the fixed length roller tray segment 802 via a fastener 822 engaged with an overhang 824. The fastener 822 can be any type of fastener including, for example, a tension stud. Other structural arrangements are possible without the combination of overhang 824 and fastener 822. The sawtooth attachment 806 includes a sawtooth surface 826.

[0056]

[0066] The sawtooth plate 828 is connected to the floor joist 804. The sawtooth plate 828 is pre-attached to the floor joist 804 prior to final assembly. The sawtooth plate 828 may be connected to the floor joist 804 with fasteners 846, 848. Alternatively, in non-limiting examples, the sawtooth plate 828 may be connected to the floor joist 804 with an adhesive or may be integrally formed with the floor joist 804. The sawtooth plate 828 includes pre-drilled holes 830, 831. The pre-drilled hole 830 has a dimension 832 and the pre-drilled hole 831 has a dimension 833. The size and shape of the pre-drilled holes 830, 831 and dimensions 832, 833 generally match the pre-drilled holes 840 and dimension 842 and pre-drilled holes 841 and dimension 843, respectively, in the floor joist 804.

[0057]

[0067] Fasteners 836, 837 connect sawtooth fitting 806 to sawtooth plate 828. Fastener 836 has a diameter 838. Fastener 837 has a diameter 839. Diameters 838, 839 are appreciably smaller than dimensions 832, 842 and dimensions 833, 843 to allow for placement of fasteners 836, 837 along the length of dimensions 532, 533, 542, 543.

[0058]

[0068] The serrations of the sawtooth surface 826 engage with the sawtooth plate 828. The engagement of the sawtooth prevents front-to-back movement of the sawtooth attachment 806 in the direction 834 relative to the sawtooth plate 828. The engagement of the sawtooth also helps prevent side-to-side movement of the sawtooth attachment 806 relative to the sawtooth plate 828. The positioning of the sawtooth attachment 806 relative to the sawtooth plate 828 is adjustable. The adjustable positioning of the sawtooth attachment 806 relative to the sawtooth plate 828 through the length of the dimensions 532, 533, 542, 543 accommodates manufacturing variations resulting from the spacing between the floor beams of the two joined fuselage sections in final assembly that may vary at each fuselage integration zone.

[0059]

[0069]

[0041] Referring now to Figure 9, a flow chart of a process 900 for installing fixed length roller tray segments across an aircraft fuselage integration zone is shown in accordance with an exemplary embodiment. The method illustrated in Figure 9 may be used in conjunction with the fixed length roller tray installation system shown in Figures 2-8.

[0060]

[0070] The process begins by installing a first set of floor beams in a first aircraft fuselage section (step 902). The process continues by installing a second set of floor beams in a second aircraft fuselage section (step 904). At least one of the first set of floor beams or the second set of floor beams includes pre-drilled holes. In step 906, the process connects the first aircraft fuselage section to the second aircraft fuselage section at a fuselage integration zone. In step 908, the process connects a sawtooth attachment to a fixed length roller tray segment. In step 910, the process connects a sawtooth plate to a set of floor beams (either the first set of floor beams or the second set of floor beams) with pre-drilled holes. The sawtooth plate surrounds the pre-drilled holes. In step 912, the process engages a sawtooth surface of the sawtooth attachment to the sawtooth plate. At step 914, the process fastens the sawtooth fitting to the first set of floor joists or the second set of floor joists with fasteners that pass through the pre-drilled holes having a dimension axially aligned with the longitudinal axis of the fixed length roller tray segment and that is larger than the diameter of the fasteners.

[0061]

[0071] In some alternative implementations of an example embodiment, one or more functions noted in a block may not be required or may occur out of the order noted in the figures. For example, in some cases, two blocks shown in succession may be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order, depending on the functionality involved. Also, other blocks may be added in addition to the blocks shown in a flowchart or block diagram.

[0062]

[0072] Example embodiments of the present disclosure may be further described in relation to aircraft manufacturing and service method 1000 as shown in Figure 10 and aircraft 1100 as shown in Figure 11. Referring initially to Figure 10, a block diagram of an aircraft manufacturing and service method is shown in accordance with an example embodiment. During pre-production, aircraft manufacturing and service method 1000 may include specification and design 1002 of aircraft 1100 as well as material procurement 1004 of Figure 11.

[0063]

[0073] During production, component and subassembly manufacturing 1006 and system integration 1008 of the aircraft 1100 of Figure 11 takes place. The aircraft 1100 of Figure 11 may then undergo certification and delivery 1010 for placement in service 1012. While in customer service 1012, the aircraft 1100 of Figure 11 is scheduled for routine maintenance and service 1014, which may include modification, reconfiguration, refurbishment, and other maintenance, upkeep, or inspection.

[0064]

[0074] The apparatus of the present disclosure may be installed on the aircraft during component and subassembly manufacturing 1006. In addition, the apparatus of the present disclosure may also be retrofitted to the aircraft 1100 of FIG. 11 during routine maintenance and service 1014 as part of a modification, reconfiguration, or refurbishment of the aircraft 1100 of FIG. 11.

[0065]

[0075] Each process of aircraft manufacturing and service method 1000 may be performed or carried out by a system integrator, a third party, an entity, or some combination thereof. In some examples, an operator may be a customer. As used herein, a system integrator may include, but is not limited to, any number of aircraft manufacturers and major system subcontractors, a third party may include, but is not limited to, any number of vendors, subcontractors, and suppliers, and an entity may be an airline, a leasing company, a military entity, a service organization, etc.

[0066]

[0076] 11 , a block diagram of an aircraft in which an illustrative embodiment may be implemented is shown. In this example, aircraft 1100 is manufactured by aircraft manufacturing and service method 1000 of FIG. 10 and may include an airframe 1102 having a number of systems 1104 and an interior 1106. Examples of systems 1104 include one or more of a propulsion system 1108, an electrical system 1110, a hydraulic system 1112, and an environmental system 1114. Any number of other systems may be included. Although an aerospace example is shown, various illustrative embodiments may be applied to other industries, such as the automotive industry.

[0067]

[0077] Apparatus and methods embodied herein may be utilized during at least one of the stages of aircraft manufacturing and service method 1000 of FIG. 10. In one illustrative example, components or subassemblies manufactured during component and subassembly manufacturing 1006 of FIG. 10 may be made or manufactured in a similar manner as components or subassemblies manufactured during service 1012 of aircraft 1100 of FIG. 10. In yet another example, one or more apparatus embodiments, method embodiments, or combinations thereof may be utilized during a production stage, such as during component and subassembly manufacturing 1006 and system integration 1008 of FIG. One or more apparatus embodiments, method embodiments, or combinations thereof may be utilized while aircraft 1100 is in service 1012, during maintenance and service 1014 (including inspection) of FIG. 10, or both. Utilization of some various illustrative embodiments may facilitate significantly more efficient assembly of aircraft 1100, reduce costs of aircraft 1100, or both significantly more efficient assembly of aircraft 1100 and reduce costs of aircraft 1100.

[0068]

[0078] The description of the various exemplary embodiments has been presented for purposes of illustration and description, and is not intended to be exhaustive or to limit the embodiments to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. Furthermore, different exemplary embodiments may provide different features compared to other preferred embodiments. The selected embodiment or embodiments have been chosen and described in order to best explain the principles and practical applications of the embodiments, and to enable others skilled in the art to understand the disclosure of the various embodiments, including various modifications suitable for the particular use contemplated.

Claims

1. A sawtooth attachment (232) for installation of a fixed length roller tray segment (230) on an aircraft (202), comprising: a first surface (244) for connecting to said fixed length roller tray segment (230); and a serrated surface (250) opposite the first surface (244), the serrated surface (250) for engaging a serrated plate (234) attached to a floor joist (220) previously installed within the aircraft (202); A sawtooth attachment, wherein fasteners (236) pass through pre-drilled holes (222) in said floor joists (220) to connect said sawtooth surface (250) to said sawtooth plate (234) and to said floor joists (220), said pre-drilled holes (222) having a dimension (224) axially aligned with a longitudinal axis (240) of said fixed length roller tray segment (230), said dimension (224) being greater than a diameter (258) of said fasteners (236).

2. The serrated attachment of claim 1, wherein a majority of a surface area (252) of said serrated surface (250) engages said serrated plate (234).

3. 2. The sawtooth attachment of claim 1, wherein the fixed length roller tray segment (230) spans a fuselage integration zone (210) of the aircraft (202), and the sawtooth attachment (232) is a split sawtooth joint including a first portion (506) connected to the fixed length roller tray segment (230) and a second portion (512) connected to a second fixed length roller tray segment (510) that does not span the fuselage integration zone (210) of the aircraft (202).

4. 2. The sawtooth attachment of claim 1, wherein the sawtooth attachment is disposed between the fixed length roller tray segment and the floor joist of the aircraft.

5. The sawtooth attachment of claim 1, wherein the sawtooth attachment (232) is disposed between the fixed length roller tray segment (230) and the sawtooth plate (234).

6. 2. The sawtooth attachment of claim 1, wherein the first surface (244) includes an overhang (246) sized for a second fastener (248) for connecting the first surface (244) to the fixed length roller tray segment (230).

7. The sawtooth fixture of claim 1 , wherein a load path (550) of the fixed length roller tray segment (230) passes through the sawtooth fixture (232).

8. The sawtooth attachment of claim 7, wherein the load path (550) of the fixed length roller tray segment (230) bypasses the fastener (236).

9. A fixed length roller tray mounting system (204), comprising: a fixed length roller tray segment (230) of an aircraft (202) connected to a sawtooth attachment (232); a sawtooth plate (234) connected to a floor beam (220) of the aircraft (202); and a serrated surface (250) of the serrated attachment (232) engaged with the serrated plate (234), the serrated attachment (232) being connected to the serrated plate (234) and the floor joist (220) with fasteners (236) that pass through pre-drilled holes (222) in the floor joist (220) of the aircraft (202).

10. 10. The system of claim 9, wherein the fixed length roller tray segment (230) spans a fuselage integration zone (210) of the aircraft (202), and the sawtooth attachment (232) is a split sawtooth joint including a first portion (506) connected to the fixed length roller tray segment (230) and a second portion (512) connected to a second fixed length roller tray segment (510).

11. 10. The system of claim 9, wherein the pre-drilled holes (222) have a dimension (224) axially aligned with a longitudinal axis (240) of the fixed-length roller tray segment (230), the dimension (224) providing a clearance fit with the fasteners (236).

12. The system of claim 9, wherein a majority of a surface area (252) of the serrated surface (250) engages the serrated plate (234).

13. 10. The system of claim 9, wherein the sawtooth attachment (232) is disposed between the fixed length roller tray segment (230) of the aircraft (202) and the floor beam (220) of the aircraft (202).

14. 10. The system of claim 9, wherein the sawtooth attachment (232) is disposed between the fixed length roller tray segment (230) and the sawtooth plate (234) of the aircraft (202).

15. 10. The system of claim 9, wherein a load path of the fixed length roller tray segment of the aircraft bypasses the fastener.

16. 16. The system of claim 15, wherein the load path (550) of the fixed length roller tray segment (230) of the aircraft (202) is also carried through the sawtooth attachment (232).

17. 1. A method for installing fixed length roller tray segments spanning an aircraft fuselage integration zone, comprising: Installing (902) a first set of floor joists (212) within a first aircraft fuselage section (206); installing (904) a second set of floor joists (214) within a second aircraft fuselage section (208), at least one of the first set of floor joists (212) or the second set of floor joists (214) including pre-drilled holes (222); joining (906) the first aircraft fuselage section (206) to the second aircraft fuselage section (208) at a fuselage integration zone (210); connecting (908) a sawtooth attachment (232) to a fixed length roller tray segment (230); connecting (910) a sawtooth plate (234) to the first set of floor joists (212) or the second set of floor joists (214) having the pre-drilled holes (222), the sawtooth plate (234) surrounding the pre-drilled holes (222); engaging (912) a serrated surface (250) of the serrated attachment (232) with the serrated plate (234); and fastening (914) the sawtooth fittings (232) to the first set of floor joists (212) or the second set of floor joists (214) with fasteners (236) through the pre-drilled holes (222); the pre-drilled hole (222) has a dimension (224) axially aligned with a longitudinal axis (240) of the fixed-length roller tray segment (230), the dimension (224) being greater than a diameter (258) of the fastener (236).

18. The method of claim 17, wherein the sawtooth fixture (232) is disposed between the fixed length roller tray segment (230) and the sawtooth plate (234).

19. The method of claim 17, wherein a load path (550) of the fixed length roller tray segment (230) bypasses the fastener (236).

20. 20. The method of claim 19, wherein the load path (550) of the fixed length roller tray segment (230) passes through the sawtooth attachment (232).

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