Patent Description:
A passenger aircraft may be converted to a freighter, or a cargo aircraft, after the aircraft has completed its operational service life as a passenger aircraft. Conversion of a passenger aircraft to a freighter includes modifying a main deck floor of the passenger aircraft to support freighter loads.

The abstract of <CIT> reads: 'The invention is directed to an adapter plate (<NUM>) for interconnecting of a device with an airplane structure. The adapter plate (<NUM>) comprises a central beam (<NUM>) area extending in a mounted position across at least two longitudinal and/or lateral floor beams (<NUM>) of a fuselage of an airplane and at least two stubs (<NUM>) arranged at an angle to the central beam area (<NUM>) in the general direction of the floor beams. The adapter plate (<NUM>) comprises fastening means to interconnect the adapter plate (<NUM>) to the floor beams (<NUM>) whereby the stubs comprise at least one channel (<NUM>) to receive an existing seat track (<NUM>) mounted on a floor beam (<NUM>).

The abstract of <CIT> reads: `An aircraft flooring system for an aircraft fuselage adapted to secure a payload component may include first and second seat tracks extending longitudinally with respect to the aircraft fuselage, the first and second seat tracks being spaced from one another; and an intercostal assembly extending between the first and second seat tracks. The intercostal assembly can include a first intercostal having a center member having a first end and a second end and a top flange including a mounting region between the first and second ends; and at least first and second tab members. The first tab member can be coupled to the top flange toward the first end of the center member and the second tab member can be coupled to the top flange toward the second end of the center member. The first and second tab members can extend beyond the first and second ends of the center member, respectively, and be configured to be coupled to the first and second seat tracks.

A floor comprises a floor beam, a seat track coupled to the floor beam and a cap coupled to at least a portion of the seat track and at least a portion of the floor beam, the cap being disposed over the floor beam and the seat track, the cap being coupled to the floor beam via a coupler, the coupler being disposed between the cap and the floor beam.

A method comprises removing a first floor panel of a floor, coupling a cap to a seat track of the floor the cap extending over at least a portion of the seat track, aligning a second floor panel with the cap, the second floor panel to be disposed over the seat track, the method further including coupling the cap to a floor beam of the floor, the floor beam being coupled to the seat track, wherein the cap is coupled to the floor beam via a coupler, the coupler disposed between the cap and the floor beam.

The figures are not to scale. In general, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts.

After a period of service as a passenger aircraft, an aircraft may be converted to a cargo aircraft or a freighter. Because freighter loads are typically heavier than passenger loads, conversion of the passenger aircraft to a freighter may involve structural modification (e.g., replacement, reinforcement) of one or more components of the aircraft to enable the aircraft to support the heavier loads in a main deck of the aircraft. Example components of the passenger aircraft that may require modification to support cargo loads include a floor of the main deck of the aircraft and stringers of the aircraft to which the skin of the aircraft is attached.

<FIG> is an example aircraft <NUM> in which examples disclosed herein may be implemented. The example aircraft <NUM> includes a fuselage <NUM> and wings <NUM>. During use of the aircraft <NUM> as a passenger aircraft, cargo such as passenger luggage is stored in a lower deck <NUM> of the fuselage <NUM> while passengers and flight crew are located in the main deck <NUM> of the fuselage <NUM>.

An interior of the fuselage <NUM> of the example aircraft <NUM> includes floor beams extending laterally or between the right and left sides of the main deck <NUM> of the aircraft <NUM>. The floor beams can be made of, for example, carbon fiber reinforced polymer (CFRP) material. The main deck <NUM> of the example aircraft <NUM> includes seat tracks that provide for attachment of seats to the tracks. The seat tracks can be coupled to the floor beams. Floor panels cover the floor beams to enable, for example, passengers to walk along the floor, sit in the seats, etc. Conversion of a passenger aircraft such as the example aircraft <NUM> of <FIG> to a freighter typically includes removal and replacement of components in the main deck <NUM> such as the floor beams and seat tracks. For example, the CFRP floor beams may be replaced with aluminum beams to increase a strength and/or a height of the floor beams to support cargo loads. However, replacement of the main deck floor and insertion of a new freighter floor can increase costs and time to convert the passenger aircraft to a freighter.

<FIG> is a partial, perspective view of a known freighter floor <NUM> disposed in a main deck <NUM> of a passenger aircraft that has been converted to a freighter (e.g., the aircraft <NUM> of <FIG>). In <FIG>, carbon-based (e.g., CFRP) floor beams of the passenger aircraft have been removed and replaced with aluminum beams <NUM>. Additionally, in the known example of <FIG>, seat tracks of the passenger aircraft have been removed and replaced with stabilization members <NUM> extending longitudinally relative to the fuselage of the aircraft. Cargo floor fittings <NUM> are coupled to the aluminum beams <NUM> to provide for attachment of, for example, cargo roller trays. Thus, in known examples, conversion of a passenger aircraft to a freighter includes replacement of the CFRP floor beams and the seat tracks with the aluminum beams <NUM> and the stabilization members <NUM>, respectively, to form the freighter floor <NUM>.

Example apparatus and methods disclosed herein provide for conversion or adaptation of a floor of a passenger aircraft to a freighter floor to support cargo loads in the main deck of the aircraft. In examples disclosed herein, caps including, for example, aluminum, are disposed along the existing floor beams of the passenger aircraft floor to reinforce or provide increased stiffness to the floor beams and, thus, strengthen the main deck floor. In examples disclosed herein, the caps include cavities to house cargo floor fittings that provide for the attachment of, for example, roller trays, cargo tracks, and/or power drive units (PDUs) of cargo handling systems. In examples disclosed herein, the caps extend over and are coupled to portions of the existing seat tracks to create a web structure including the floor beams and the seat tracks of the original passenger aircraft floor with the addition of the caps. Floor panels can be aligned with the caps to create a substantially level freighter floor to support the cargo loads, to enable users to walk on the floor, etc. Thus, in examples disclosed herein, the main deck floor of the passenger aircraft is adapted or modified, rather than replaced, during conversion of the passenger aircraft to a freighter.

In some disclosed examples, the caps are coupled to the floor beams via one or more attachments or couplers (e.g. shear clips) to account for shear forces. In some examples, the intercostal members including the caps are disposed in the main deck at an overwing section proximate to the aircraft wings where there may be a reduced number of lateral floor beams and, instead, primarily longitudinal floor beams to support the seat tracks. The intercostal members strengthen the overwing section of the aircraft to accommodate cargo loads. In such examples, the intercostal members include flanges coupled to the caps. The flanges strengthen and stiffen the intercostal members for supporting cargo loads. Thus, rather than replacing the floor of a passenger aircraft with a new floor during conversion of the passenger aircraft to a freighter, examples disclosed herein adapt and reinforce the existing floor throughout the main deck, thereby reducing time and costs for freighter conversions.

Although examples disclosed herein are discussed in the context of converting passenger aircraft floors to freighter floors to support cargo loads in the main deck of the aircraft in connection with freighter conversion, examples disclosed herein may be implemented in the context of freighter production. For example, a freighter aircraft can be built (i.e., not converted from a passenger plane) to include the example freighter floor and/or one or more components thereof disclosed herein. Also, although examples disclosed herein are discussed in the context of aircraft, examples disclosed herein could be implemented in other vehicles (e.g., ships or other watercraft).

<FIG> is a partial, perspective view of a first example freighter floor <NUM> in accordance with teachings of this disclosure. The first example freighter floor <NUM> of <FIG> is disposed in a main deck <NUM> of an aircraft (e.g., the aircraft <NUM> of <FIG>). The portion of the main deck <NUM> illustrated in <FIG> can be disposed forward or rearward of an overwing section of the aircraft (i.e., a section of the fuselage proximate to wings).

The example main deck <NUM> of <FIG> includes a plurality of floor beams <NUM> extending laterally between a first side <NUM> of the main deck <NUM> and a second side <NUM> of the main deck <NUM>. The floor beams <NUM> can include a carbon-based material such as CFRP. The example main deck <NUM> of <FIG> includes a plurality of seat tracks <NUM> extending longitudinally along the main deck <NUM>. The seat tracks <NUM> may be coupled to the floor beams <NUM> via, for example, aluminum shear clips. For illustrative purposes, floor panels covering the floor beams <NUM> are not shown in <FIG>. Also, the example main deck <NUM> can include additional or fewer floor beams <NUM> and/or seat tracks <NUM> than illustrated in <FIG>.

In the example of <FIG>, caps <NUM> are disposed laterally in the main deck <NUM> along a length of or substantially along a length of each floor beam <NUM>. The cap(s) <NUM> can be made of a material such as, for example, aluminum, titanium, and/or steel. As illustrated in <FIG>, the caps <NUM> extend over and substantially perpendicular to the seat tracks <NUM>. As discussed herein, in the example of <FIG>, each cap <NUM> is coupled to at least a portion of one or more seat tracks <NUM>. In some examples, at least a portion of the cap(s) <NUM> is coupled to the respective floor beam(s) <NUM>.

In the example of <FIG>, each of the caps <NUM> includes one or more cavities <NUM> defined therein to house a cargo fitting <NUM>. The cargo fitting(s) <NUM> provide means for removably coupling or securing, for instance, PDUs, roller tray, cargo tracks, and/or other cargo handling system components to the freighter floor <NUM>. Each of the caps <NUM> can include additional or fewer cavities <NUM> and/or house additional or fewer cargo fittings <NUM> than illustrated in <FIG>.

Thus, in the example of <FIG>, the freighter floor <NUM> includes the pre-existing floor beams <NUM> and the pre-existing seat tracks <NUM> from when the main deck <NUM> was used to carry passengers with the addition of the caps <NUM> to reinforce the floor beams <NUM> and the seat tracks <NUM> to support cargo loads. As compared to the known example freighter floor <NUM> of <FIG>, the example freighter floor <NUM> of <FIG> is adapted to carry cargo loads using the existing floor components of the passenger aircraft (e.g., the floor beams <NUM>, the seat tracks <NUM>). In the example of <FIG>, the caps <NUM> are placed over (e.g., on top of) of the floor beams <NUM> and the seat tracks <NUM>. Floor panels can be aligned with the caps <NUM> to create a substantially level surface for placing cargo loads, for walking, etc. As a result, the freighter floor <NUM> includes a first floor level including the floor beams <NUM> and the seat tracks <NUM> (i.e., the existing floor) and a second floor level including the caps <NUM> and floor panels.

<FIG> is a top, front perspective view of one of the caps <NUM> and one of the floor beams <NUM> of <FIG>. <FIG> is a partial, perspective view of a portion <NUM> of the cap <NUM> and the floor beam <NUM> of <FIG>. For illustrative purposes, the seat track(s) <NUM> are not shown in <FIG>.

As illustrated in <FIG>, the cap <NUM> includes one or more cavities <NUM> to receive the cargo fittings <NUM>. A shape and/or size of the cavities <NUM> can be selected based on the type of cargo fittings <NUM> to be used with the cap <NUM>.

As also illustrated in <FIG>, the example cap <NUM> includes notches or grooves <NUM> defined by respective first and second edges <NUM>, <NUM> of the cap <NUM>. In the example of <FIG>, a groove <NUM> defined by the first edge <NUM> is substantially aligned with a corresponding groove <NUM> defined by the second edge <NUM> of the cap <NUM>. Thus, the cap <NUM> includes pairs of grooves <NUM> at the first and second edges <NUM>, <NUM>. As discussed below, each pair of grooves <NUM> provides for alignment of the cap <NUM> with the seat track(s) <NUM> of <FIG>. A first surface <NUM> of the cap <NUM>, or a surface facing away from the floor beam <NUM>, includes one or more openings <NUM> defined therein proximate to the grooves <NUM>. As discussed below, the opening(s) <NUM> receive mechanical fastener(s) (e.g., studs, screws, etc.) to couple a portion of the cap <NUM> to a seat track <NUM> when the grooves <NUM> are aligned with the seat track <NUM>. The example cap <NUM> can include additional or fewer openings <NUM> than illustrated in <FIG>.

<FIG> is a cross-sectional view of a portion of the cap <NUM> of <FIG> taken along the <NUM>-<NUM> line of <FIG>. As shown in <FIG>, the cap <NUM> includes a floor beam coupler <NUM> extending from a second or floor beam-facing surface <NUM> of the cap <NUM> opposite the first surface <NUM> of the cap <NUM>. The floor beam coupler <NUM> provides an interface for coupling a portion of the cap <NUM> (e.g., a portion of the cap <NUM> not coupled to a seat track <NUM>) to at least a portion of the floor beam <NUM>. In some examples, the cap <NUM> includes one floor beam coupler <NUM>. In other examples, the cap <NUM> includes two or more floor beam couplers <NUM> disposed along a length of the surface <NUM> of the cap <NUM>. For example, the floor beam couplers <NUM> can be disposed along the length of the cap <NUM> between the grooves <NUM> of the cap <NUM>. The floor beam coupler <NUM> can be made of, for example, aluminum.

In the example of <FIG>, the floor beam coupler <NUM> of <FIG> has a substantially T shape. The example floor beam coupler (s) <NUM> can have other shapes and/or sizes than illustrated in <FIG>. For example, the size and/or shape of the floor beam coupler(s) <NUM> may be based on a length of the cap <NUM>, a width of the floor beam <NUM>, distances between pairs of grooves <NUM> of the cap <NUM>, a height of the seat track <NUM> (which can define a distance between the first surface <NUM> of the cap <NUM> and the floor beam <NUM>), etc. Also, in some examples, the floor beam coupler <NUM> is integrally formed with the cap <NUM>. In other examples, the floor beam coupler <NUM> is formed separately and coupled to the floor-beam facing surface <NUM> of the cap <NUM>.

<FIG> is a partial, perspective view of the example cap <NUM> of <FIG> extending over the floor beam <NUM> and one of the seat tracks <NUM> of <FIG>. As illustrated in <FIG>, in use, the grooves <NUM> of the cap <NUM> are aligned or substantially aligned with the seat track <NUM>. As also illustrated in <FIG>, the opening(s) <NUM> of the cap <NUM> are aligned with opening(s) <NUM> in the seat track <NUM>. In the example of <FIG>, the cap <NUM> can be coupled to the seat track <NUM> via mechanical fastener(s) <NUM> (e.g., studs) extending through the respective openings <NUM>, <NUM> of the cap <NUM> and the seat track <NUM>. Thus, the example floor <NUM> utilizes existing coupling mechanisms such as the openings <NUM> of the seat track <NUM> to add the caps <NUM> to the passenger aircraft floor, thereby reducing the need to provide for new couplings between the caps <NUM> and the existing floor components (e.g., by reducing an amount of drilling required to add the caps <NUM> to the floor).

<FIG> is a cross-sectional view of the example cap <NUM>, the example seat track <NUM>, and the example floor beam <NUM> taken along the <NUM>-<NUM> line of <FIG> shows the coupling between the seat track <NUM> and the floor beam <NUM> via a shear clip <NUM>. Thus, when the floor is used as a passenger aircraft floor including the floor beams <NUM> and the seat tracks <NUM>, the floor beams <NUM> and the seat tracks <NUM> are coupled to form a structural web to support passenger loads. As discussed herein, the coupling of the cap <NUM> to the floor beam <NUM> via the floor beam coupler <NUM> of <FIG> provides for increased stiffness of the floor beam <NUM> and, overall, increased strength of the structural web formed by the floor beams <NUM>, the seat tracks <NUM>, and the caps <NUM>.

<FIG> is a side view of the example cap <NUM> of <FIG> extending over the floor beam <NUM> and one of the seat tracks <NUM> of <FIG>. In the example of <FIG>, floor panels <NUM> are disposed proximate to the cap <NUM> and above the seat track <NUM>. The floor panels <NUM> can be different floor panels from the floor panels of the passenger aircraft or the same floor panels. As illustrated in <FIG>, the floor panels <NUM> are substantially aligned with the cap <NUM> such that the first surface <NUM> of the cap <NUM> and respective surfaces <NUM> of the floor panels <NUM> form a substantially level surface. In some examples, a height of the cap <NUM> is selected based on a height of the floor panels <NUM> so as to create the substantially level surface. As also shown in <FIG>, the cargo fitting <NUM> may be substantially raised relative to the surface <NUM> of the cap <NUM> and the surface <NUM> of the floor panels <NUM> to provide ease of access to the cargo fitting <NUM> when coupling and uncoupling cargo handling system components (e.g., roller trays) to the fitting <NUM>.

As also illustrated in <FIG>, as a result of the placement of the cap <NUM> over the seat track <NUM> and the placement of the floor panels <NUM> above the seat track <NUM>, the example freighter floor <NUM> of <FIG> is raised as compared to when the floor panels are substantially aligned with the seat tracks <NUM>, as is the case when the main deck floor is used for passenger carrying purposes. For example, the freighter floor <NUM> of <FIG> may be raised approximately <NUM> inches as compared to a main deck floor of a passenger aircraft.

<FIG> is a partial side view of the example cap <NUM> of <FIG> with the seat track <NUM> of <FIG> removed to show the coupling of the floor beam coupler <NUM> of the cap <NUM> to a seat track-facing surface <NUM> the floor beam <NUM>. As shown in <FIG>, in use, the floor beam coupler <NUM> of the cap <NUM> is disposed between the seat tracks <NUM> (e.g., between the seat track <NUM> of <FIG> and the seat track <NUM> of <FIG>). The floor beam coupler <NUM> of the cap <NUM> can be coupled to the surface <NUM> of the floor beam <NUM> via one or more fasteners (e.g., mechanical fasteners such as screws, chemical fasteners, etc.).

In the example of <FIG>, the coupling of the floor beam coupler <NUM> of the cap <NUM> to the floor beam <NUM> provides for increased stiffness of the floor beam <NUM>. The cap <NUM> and the floor beam <NUM> essentially form a single beam at the portions where the floor beam coupler <NUM> couples to the floor beam <NUM>. The coupling of the cap <NUM> to the floor beam <NUM> can reduce instances of twisting or bending of the floor beam <NUM> due to shear flow. In some examples, a vertical stiffness of the (e.g., CFRP) floor beam <NUM> when coupled to the cap <NUM> increase <NUM> times as compared to when the floor beam <NUM> is not coupled to cap <NUM>. Further, as mentioned above, the seat track <NUM> is coupled to the floor beam <NUM>. Thus, the example floor <NUM> forms a web including the cap <NUM>, the seat track <NUM>, and the floor beam <NUM> having increased strength and stiffness as compared to floor prior to the addition of the cap and the couplings between the cap <NUM>, the seat track <NUM>, and the floor beam <NUM>.

The coupling of the cap(s) <NUM> to the floor beam(s) <NUM> via the floor beam coupler(s) <NUM> and the coupling of the cap(s) <NUM> to the seat track(s) <NUM> via the openings <NUM> creates a floor having increased strength as compared to floors that do not include the cap(s) <NUM>. As an example, the strength of the example floor <NUM> can increase from <NUM> Kpa (<NUM> lbs/in) during use as a passenger aircraft floor to <NUM>. 3Kpa (<NUM> lbs/in) after the inclusion of the caps <NUM>. The increased stiffness and strength of the example floor <NUM> enables the floor <NUM> to support cargo loads. In the examples of <FIG>, the cap(s) <NUM> reinforce the floor beams <NUM> without requiring removal and replacement of the floor beams <NUM> and/or the seat tracks <NUM> to support cargo loads.

<FIG> is a partial, perspective view of a second example freighter floor <NUM> in accordance with teachings of this disclosure. The example freighter floor <NUM> of <FIG> may be disposed in a portion of a main deck of an aircraft (e.g., the aircraft <NUM> of <FIG>) disposed forward or rearward of the overwing section of the main deck of the aircraft.

The example freighter floor <NUM> of <FIG> includes a plurality of floor beams <NUM> extending laterally between right and left sides of the main deck of the aircraft as substantially disclosed above in connection with the floor beams <NUM> of <FIG>. The example freighter floor <NUM> includes a plurality of seat tracks <NUM> extending longitudinally along the main deck substantially disclosed above in connection with the seat tracks <NUM> of <FIG>. For illustrative purposes, floor panels covering the floor beams <NUM> are not shown in <FIG>. Also, the example freighter floor <NUM> can include additional or fewer floor beams <NUM> and/or seat tracks <NUM> than illustrated in <FIG>.

In the example of <FIG>, caps <NUM> are disposed laterally along a length of each floor beam <NUM>. The caps <NUM> can be made of, for example, aluminum, titanium, steel, etc. As illustrated in <FIG>, the caps <NUM> extend over and substantially perpendicular to the seat tracks <NUM>. As discussed herein, in the example of <FIG>, each cap <NUM> is coupled to at least a portion of a floor beam <NUM> and one or more seat tracks <NUM> to reinforce the floor beam <NUM> to support cargo loads. In the example of <FIG>, each of the caps <NUM> includes at least one floor beam coupler <NUM> to couple the cap(s) <NUM> to corresponding floor beam(s) <NUM>. As also illustrated in <FIG>, the caps <NUM> include cavities <NUM> to receive cargo fittings <NUM> for coupling components of a cargo handling system (e.g., roller trays, PDUs) to the freighter floor <NUM>, as substantially discussed above in connection with <FIG>.

<FIG> is a partial, perspective view of one of the example caps <NUM> of <FIG> extending over one of the seat tracks <NUM> and one of the floor beams <NUM> of <FIG>. As illustrated in <FIG>, the cap <NUM> includes notches or grooves <NUM> formed in respective edges <NUM>, <NUM> of the cap <NUM>. The grooves <NUM> are aligned or substantially aligned with the seat track <NUM>. As also illustrated in <FIG>, the cap <NUM> includes one or more openings <NUM> defined in a surface <NUM> of the cap <NUM>. The opening(s) <NUM> can receive fastener(s) <NUM> (e.g., studs) for coupling the cap <NUM> to the seat track <NUM> via openings <NUM> of the seat track <NUM>.

<FIG> illustrates that one of more characteristics of the caps <NUM>, <NUM> of <FIG> can be selected based on the characteristics of the seat tracks <NUM>, <NUM> and/or the floor beams <NUM>, <NUM> to which the caps <NUM>, <NUM> are to be coupled. For example, a width of the grooves <NUM>, <NUM> can be selected based on differing styles of the seat track <NUM>, <NUM>, such as track width, as shown in <FIG> and <FIG>. Thus, the caps <NUM>, <NUM> can be designed to convert passenger main deck floors having different characteristics to freighter floors at reduced costs as compared to designing complete, custom freighter floors for each aircraft.

<FIG> is a partial side view of the example cap <NUM> of <FIG> with the seat track <NUM> of <FIG> removed to show the coupling of the floor beam coupler <NUM> of the cap <NUM> to the floor beam <NUM>. As shown in <FIG>, the floor beam coupler <NUM> couples the cap <NUM> to the floor beam <NUM> between the seat tracks <NUM> (e.g., the seat track <NUM> of <FIG> and the seat track <NUM> of <FIG>). The coupling of the cap <NUM> to the floor beam <NUM> via the floor beam coupler <NUM> increases a stiffness of the floor beam <NUM> by reducing the effects of shear forces on the floor beam <NUM>, which could cause twisting or bending. In some examples, the floor beam coupler <NUM> is integrally formed with the cap <NUM>. In other examples, the floor beam coupler <NUM> is formed separately from the cap <NUM> and coupled thereto.

As illustrated in <FIG>, a shape and/or size of the floor beam coupler <NUM> and/or a manner of coupling the floor beam coupler <NUM> to the floor beam can differ from the floor beam coupler <NUM> of <FIG> based on, for example, a shape of the floor beam. For instance, as illustrated in <FIG>, the floor beam coupler <NUM> can couple to the floor beam <NUM> along at least a portion of a height of the floor beam <NUM>, as compared to the coupling of the floor beam coupler <NUM> of <FIG> to the seat-track facing surface <NUM> of the floor beam <NUM> as shown in <FIG>.

<FIG> illustrate example freighter floors <NUM>, <NUM> that may be used in a main deck of an aircraft to convert the aircraft from a passenger aircraft to a freighter. However, the floor of the main deck may not be uniform along a length of the main deck with respect to, for example, a number of floor beams, a direction of the floor beams relative to the fuselage, etc. For example, the overwing section of the aircraft may include fewer lateral floor beams than the portions of main deck that are in front of or behind the overwing section. Further, behavior of the aircraft at different portions of the main deck, such as proximate to the wings, may differ. For example, the wings of the aircraft flex during use, which can generate forces that affect the floor beams disposed proximate to the wings. Thus, reinforcement of the floor at the overwing section of the aircraft may differ from reinforcement of a remainder of the main deck floor.

<FIG> is a partial, perspective view of an example overwing floor <NUM> in accordance with teachings of this disclosure. The example overwing floor <NUM> of <FIG> is disposed in an overwing section <NUM> of an aircraft (e.g., the aircraft <NUM> of <FIG>), or a section proximate to (e.g., substantially aligned with) the wings. As illustrated in <FIG>, the example overwing section <NUM> includes a plurality of longitudinal floor beams <NUM>. The floor beams <NUM> support seat tracks <NUM> extending longitudinally along the floor beams <NUM>.

In the example of <FIG>, a plurality of intercostal members <NUM> including caps <NUM> extend across the seat tracks <NUM> in a direction substantially perpendicular to the seat tracks <NUM> and the floor beams <NUM>. As illustrated in <FIG>, the caps <NUM> includes a plurality of cavities <NUM> to receive cargo fittings <NUM>, substantially as disclosed above in connection with <FIG>.

<FIG> is a partial view of one of the intercostal members <NUM> including an example cap <NUM> of <FIG> extending over one of the seat tracks <NUM> and one of the floor beams <NUM>. As shown in <FIG>, respective edges <NUM>, <NUM> of the cap <NUM> include notches or grooves <NUM> defined therein. As also shown in <FIG>, a first surface <NUM> of the cap <NUM> includes one or more openings <NUM> defined therein. In use, the grooves <NUM> of the cap <NUM> are aligned with the seat track <NUM>, substantially as disclosed above in connection with <FIG>. The opening(s) <NUM> of the cap <NUM> receive fastener(s) <NUM> (e.g., studs, screws, etc.) to couple the cap <NUM> to the seat track <NUM> via openings <NUM> defined in the seat track <NUM>, substantially as disclosed above in connection with <FIG>.

As illustrated in <FIG> and <FIG>, the example overwing section <NUM> does not include lateral floor beams as in the examples of <FIG> (e.g., the lateral floor beams <NUM>, <NUM> of <FIG>). Instead, the example overwing section <NUM> of <FIG> includes the longitudinal floor beams <NUM> over which the seat tracks <NUM> extend. Thus, unlike in the examples of <FIG>, the overwing section <NUM> of <FIG> does not include lateral floor beam(s) to which the cap(s) <NUM> can be coupled via a shear attachment(s), such as the floor beam couplers <NUM>, <NUM> of <FIG> and <FIG>.

<FIG> is a side view of the example intercostal member <NUM> of <FIG> and one of the seat tracks <NUM> of <FIG>. The example intercostal member <NUM> of <FIG> includes flange(s) <NUM> extending from a second surface <NUM> of the cap <NUM>, or a surface opposite the first surface <NUM>. In use, the flange(s) <NUM> of <FIG> are disposed between two of the seat tracks <NUM>. Also, in some examples, the flanges <NUM> are integrally formed with the cap <NUM>. In other examples, the flanges <NUM> are formed separately and coupled to the second surface <NUM> of the cap <NUM>. The example flange(s) <NUM> provide strength and stiffness to the intercostal member <NUM> for accommodating cargo loads (e.g., so that the entire load is not carried by the cap <NUM>).

Overwing structures of aircrafts should be able to flex to account for wing compression and tension during flight. In some examples, the intercostal member(s) <NUM> of <FIG> are coupled to the longitudinal floor beam(s) <NUM> via the seat track(s) <NUM> using slotted bushing(s). For instance, the bushing can be fastened (e.g., bolted) to the seat track <NUM>. The slotted bushing allows the longitudinal floor beam <NUM> to move laterally underneath the intercostal member <NUM>. In such examples, the slotted bushing provides a vertical load path for loads placed on the intercostal member <NUM> as well as a forward and aft load path. In some examples, an interface between the intercostal member <NUM> and the longitudinal floor beam <NUM> (e.g., proximate to the seat track <NUM>) includes a finish treatment such as a Teflon® paint or other coating to facilitate sliding between the intercostal member <NUM> and the longitudinal floor beam <NUM> (e.g., the seat track <NUM>). Other types of fasteners can be used in addition to or as an alternative to the slotted bushing (e.g., tie rods).

As also shown in <FIG>, floor panels <NUM> can be disposed proximate to the cap <NUM> to create a substantially level surface between the cap <NUM> and the floor panels <NUM>. Thus, the example overwing floor <NUM> of <FIG> provides for reinforcement of the overwing section <NUM> of the aircraft to support cargo loads while accounting for the effects of wing flexure on the floor beams <NUM>.

<FIG> are top views of example cargo fittings <NUM>, <NUM>, <NUM>, <NUM> that may be used with the example caps <NUM>, <NUM>, <NUM> of <FIG>. The example cargo fittings <NUM>, <NUM>, <NUM>, <NUM> can correspond to the example cargo fittings <NUM>, <NUM>, <NUM> of <FIG>. As illustrated in <FIG>, the cargo fittings <NUM>, <NUM>, <NUM>, <NUM> include tracks <NUM> defined therein to receive corresponding track attachment pieces or fittings of one or more cargo handling system components, such as roller trays, PDUs, etc. As shown in <FIG>, the track style, length, width, shape, etc. of the cargo fittings <NUM>, <NUM>, <NUM>, <NUM> can vary based on the cargo handling system components to be attached thereto.

As mentioned above, the example cargo fittings <NUM>, <NUM>, <NUM>, <NUM> of <FIG> can be disposed in the cavities <NUM>, <NUM>, <NUM> of the caps <NUM>, <NUM>, <NUM>. The example cargo fittings <NUM>, <NUM>, <NUM>, <NUM> include one or more openings <NUM> defined therein to enable the cargo fittings to be removably coupled to the cavities <NUM>, <NUM>, <NUM> of the caps <NUM>, <NUM>, <NUM> via one or more mechanical fasteners (e.g., screws). The removable coupling of the cargo fitting(s) <NUM>, <NUM>, <NUM>, <NUM> to the cap(s) <NUM>, <NUM>, <NUM> provides for ease of replacement of the cargo fitting in the event the cargo fitting(s) are damaged during use. Instead of replacing the cap <NUM>, <NUM>, <NUM> including the damaged cargo fitting <NUM>, <NUM>, <NUM>, <NUM>, the cargo fitting can be replaced, which reduces costs and maintenance of the freighter floor <NUM>, <NUM>, <NUM>.

<FIG> is a partial side view of an example freighter floor <NUM> in accordance with teachings disclosed herein and illustrating an example roller tray <NUM> supported by the freighter floor <NUM>. The example freighter floor <NUM> of <FIG> can correspond to, for example, the example freighter floor <NUM> of <FIG> or the example freighter floor <NUM> of <FIG>. As illustrated in <FIG>, the example freighter floor <NUM> includes a first floor beam <NUM> and a second floor beam <NUM> and a seat track <NUM> disposed perpendicular to the floor beams <NUM>, <NUM>. The example freighter floor <NUM> includes a first cap <NUM> extending across the seat track <NUM> proximate to the first floor beam <NUM> and a second cap <NUM> extending across the seat track <NUM> proximate to the second floor beam <NUM>, as substantially discussed above in connection with <FIG>.

As illustrated in <FIG>, floor panels <NUM> are aligned with the caps <NUM>, <NUM> to create a substantially level surface across which, for example, a user can walk and/or the roller tray <NUM> (or other cargo handling system component) can rest. In the example of <FIG>, the roller tray <NUM> is coupled to respective cargo fittings <NUM> of the first and second caps <NUM>, <NUM>. Thus, in the example of <FIG>, the caps <NUM>, <NUM> and the floor panels <NUM> create a supplemental floor level relative to the existing floor previously defined by the floor beams <NUM>, <NUM> and the seat track <NUM> before the addition of the caps <NUM>, <NUM> (e.g., the passenger aircraft floor).

<FIG> is a flowchart of an example method <NUM> to convert a passenger aircraft floor to a freighter floor in accordance with teachings of this disclosure. The example method <NUM> begins with removing floor panels of a main deck floor of an aircraft (block <NUM>). Removing the floor panels provides access to floor beams covered by the floor panels, such as the floor beams <NUM>, <NUM>, <NUM> of <FIG>, <FIG>, and <FIG>.

The example method <NUM> includes a determination of whether an overwing section or a non-overwing section of the main deck floor is to be converted to a freighter floor (block <NUM>). For example, the overwing section may include fewer lateral floor beams than the non-overwing section of the main deck.

If the non-overwing section of the main deck floor is to be converted to the freighter floor, the example method <NUM> includes aligning cap(s) along lateral floor beam(s) of the main deck floor, perpendicular to seat track(s) of the floor (block <NUM>). For example, the cap(s) <NUM>, <NUM>, <NUM>, <NUM> can be aligned relative to the lateral floor beam(s) <NUM>, <NUM>, <NUM>, <NUM> of <FIG>, <FIG>, and <FIG> to extend along a length of floor beam(s), substantially perpendicular to the seat track(s) <NUM>, <NUM>, <NUM> of <FIG>, <FIG>, and <FIG>. The cap(s) <NUM>, <NUM>, <NUM>, <NUM> can be positioned relative to the later floor beam(s) <NUM>, <NUM>, <NUM>, <NUM> and the seat track(s) <NUM>, <NUM>, <NUM> such that the groove(s) <NUM>, <NUM> of the cap(s) <NUM>, <NUM> are aligned with the seat track(s) <NUM>, <NUM>, <NUM>.

The example method <NUM> includes coupling the cap(s) to the seat track(s) (block <NUM>). For example, the cap(s) <NUM>, <NUM>, <NUM>, <NUM> of <FIG>, <FIG>, and <FIG> can be coupled to the seat track(s) <NUM>, <NUM>, <NUM> via fastener(s) <NUM>, <NUM> (e.g., stud(s)) extending through the opening(s) <NUM>, <NUM> of the cap(s) <NUM>, <NUM> and the opening(s) <NUM>, <NUM> of the seat track(s) <NUM>, <NUM>.

The example method <NUM> includes coupling cap(s) to the floor beam(s) (block <NUM>). For example, the cap(s) <NUM>, <NUM>, <NUM>, <NUM> of <FIG>, <FIG>, and <FIG> can be coupled to the floor beam(s) <NUM>, <NUM>, <NUM>, <NUM> via the floor beam coupler(s) <NUM>, <NUM> of <FIG> and <FIG>. In some examples, the floor beam coupler(s) <NUM> are coupled to seat track-facing surface(s) <NUM> of the floor beam(s) <NUM> (e.g., <FIG>). In other examples, the floor beam coupler(s) <NUM> are coupled to the floor beam(s) <NUM> along at least a portion of a length of the floor beam(s) <NUM> (e.g., <FIG>). The manner in which the cap(s) <NUM>, <NUM> are coupled to the floor beam(s) <NUM>, <NUM> can be based on, for example, a shape and/or size of the floor beam(s) and/or the seat track(s), a design of the floor beam coupler(s) <NUM>, <NUM>, etc..

The example method <NUM> includes coupling cargo fitting(s) to the cap(s) (block <NUM>). For example, the cargo fitting(s) <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> can be disposed in the cavities <NUM>, <NUM> of the cap(s) <NUM>, <NUM>, <NUM>, <NUM> and coupled to the cap(s) via mechanical fastener(s). In some examples, the cargo fitting(s) are coupled to the cap(s) prior to the aligning of the cap(s) with the floor beam(s) (e.g., prior to block <NUM>) such that the cargo fitting(s) and the cap(s) are installed as a unit.

In the example of <FIG>, if the overwing section of the main deck floor is to be converted to a freighter floor, the method <NUM> includes aligning intercostal member(s) perpendicular to seat track(s) and longitudinal floor beam(s) supporting the seat track(s) (block <NUM>). For example, intercostal member(s) <NUM> including the cap(s) <NUM> and the flange(s) <NUM> can be aligned perpendicular to the seat track(s) <NUM> and the floor beam(s) <NUM> as shown in <FIG>.

The example method <NUM> includes coupling the cap(s) of the intercostal member(s) to the seat track(s) (block <NUM>). For example, the cap(s) <NUM> of <FIG> can be coupled to the seat track(s) <NUM> via fastener(s) <NUM> extending through opening(s) <NUM> of the cap(s) <NUM> and opening(s) <NUM> of the seat track(s) <NUM>.

The example method <NUM> includes coupling the cargo fitting(s) to the cap(s) of the intercostal member(s) (block <NUM>). For example, the cargo fitting(s) <NUM>, <NUM>, <NUM>, <NUM>, <NUM> can be disposed in the cavities <NUM> of the cap(s) <NUM> and coupled to the cap(s) via mechanical fastener(s). In some examples, the cargo fitting(s) are coupled to the cap(s) prior to the aligning of the intercostal member(s) with the seat track(s) (e.g., prior to block <NUM>) such that the cargo fitting(s) and the intercostal member(s) are installed as a unit.

The example method <NUM> includes aligning floor panels with the intercostal member(s) (block <NUM>). For example, the floor panel(s) <NUM>, <NUM> of <FIG> and <FIG> can be aligned with the cap(s) <NUM>, <NUM>, <NUM> to create a substantially level surface, as shown in <FIG> and <FIG>. The floor panel(s) <NUM> can be disposed over the seat track(s) <NUM>, <NUM>, <NUM>, <NUM> to create a raised floor level including the cap(s) <NUM>, <NUM>, <NUM> and the floor panel(s) <NUM>, <NUM>.

The example method <NUM> ends when there are no further sections of the main deck floor of the passenger aircraft to be converted to a freighter floor (block <NUM>).

Although the example method <NUM> is described with reference to the flowchart illustrated in <FIG>, many other method of converting a passenger aircraft floor to a freighter floor may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined. Similarly, additional operations may be included in the example method of <FIG> before, in between, or after the blocks shown in <FIG>.

From the foregoing, it will be appreciated that example methods, apparatus and articles of manufacture have been disclosed that provide for conversion of a main deck floor of a passenger aircraft to a freighter floor to support cargo loads. Examples disclosed herein adapt existing passenger aircraft floors to freighter floors with the addition of caps that extend over the floor beams and the seat tracks of the passenger aircraft floors. The caps increase stiffness and strength of the existing floors. In some examples, flanges are coupled to the caps to form intercostal members that strengthen the aircraft floor proximate to the overwing sections of the aircraft. Example caps disclosed herein include cargo fittings to enable cargo handling system components, such as roller trays, to be securely coupled to the floors. Examples disclosed herein provide for efficient conversion of main decks floors of passenger aircrafts to freighter floors without requiring removal and replacement of the existing floors. As a result, examples disclosed herein reduce costs and time to convert passenger aircrafts to freighters.

The term "and/or" when used, for example, in a form such as A, B, and/or C refers to any combination or subset of A, B, C such as (<NUM>) A alone, (<NUM>) B alone, (<NUM>) C alone, (<NUM>) A with B, (<NUM>) A with C, and (<NUM>) B with C.

Claim 1:
A floor (<NUM>, <NUM>, <NUM>, <NUM>) comprising:
a floor beam (<NUM>,<NUM>,<NUM>, <NUM>, <NUM>);
a seat track (<NUM>, <NUM>, <NUM>, <NUM>) coupled to the floor beam (<NUM>,<NUM>,<NUM>, <NUM>, <NUM>); and
a cap (<NUM>, <NUM>,<NUM>, <NUM>, <NUM>) coupled to at least a portion of the seat track and (<NUM>, <NUM>, <NUM>, <NUM>) at least a portion of the floor beam (<NUM>,<NUM>,<NUM>, <NUM>, <NUM>), the cap (<NUM>, <NUM>,<NUM>, <NUM>, <NUM>) disposed over the floor beam (<NUM>,<NUM>,<NUM>, <NUM>, <NUM>) and the seat track (<NUM>, <NUM>, <NUM>, <NUM>),
wherein the cap (<NUM>, <NUM>,<NUM>, <NUM>, <NUM>) is coupled to the floor beam (<NUM>,<NUM>,<NUM>, <NUM>, <NUM>) via a coupler (<NUM>,<NUM>), the coupler (<NUM>, <NUM>) disposed between the cap (<NUM>, <NUM>,<NUM>, <NUM>, <NUM>) and the floor beam (<NUM>,<NUM>,<NUM>, <NUM>, <NUM>).