Patent Description:
Carbon fiber reinforced plastic (CFRP) materials are increasingly being used in place of aluminum materials to form skin panels and structural members of an aircraft. For example, the wings of an aircraft may be constructed of CFRP materials. It is to be appreciated that CFRP materials provide several advantages when compared to aluminum materials such as, for example, higher strength-to-weight ratios. However, CFRP materials offer less protection against electromagnetic effects (EME) created by lightning strikes when compared to aluminum materials.

Fuel tanks are commonly located within the aircraft wings. For example, surge fuel tanks are commonly located within the wing tips of an aircraft where space is restricted. However, because of the reduced EME protection afforded by CFRP materials, conductive systems of the aircraft's fuel tanks may be forced to carry more of the current induced by a lightning strike event. Sparking caused by a lightning strike is to be avoided in the presence of fuel vapors outboard of the wing's fuel tanks. As a result, in conventional systems, power feeder wires do not pass through areas of the CFRP wing that may potentially comprise a threshold amount of volatile liquid or gases (e.g., fuel vapor), such as the area outboard of the surge fuel tank (e.g., a leakage zone located outboard of the surge fuel tank). Instead, the power feeder wires are typically routed along either the wing's front spar or rear spar.

There may be drawbacks to routing the power feeder wires along either the front or rear spar. This is because some external components of the aircraft, such as the windshield, the nose, and the leading and trailing edges of the wings, may experience less than optimal performance caused by object impact. For example, a bird strike may occur along the leading edge of one of the aircraft's wings. Since the front spar is disposed along the leading edge and the rear spar is disposed along the trailing edge of the aircraft's wings, the power feeder wires that are routed along the front or rear spar may experience less than optimal performance during object impact. Therefore, there is a desire for an improved system and method for routing power feeder wires through enclosed spaces that may potentially comprise volatile liquid or gas. There is also a desire for an improved system and method for routing power feeder wires through areas of an aircraft wing, such as the area of the wing outboard of the surge fuel tank.

Additionally, it is also to be appreciated that the aircraft wing is also subject to thermal expansion and contraction as well as vibration during operation. Therefore, there is a desire for an improved system and method for routing power feeder wires through a structure that is subject to expansion, contraction, and vibration.

The abstract of <CIT> refers to a wire cable assembly such as those used in electric or hybrid electric vehicles, having a plurality of shielded wire cables spliced together. The center conductors are joined together and enclosed in an inner insulator. The shield conductors of the cable are joined by an electrically conductive sleeve enclosing the inner insulator and attached to the shield conductors of the shielded wire cables. The sleeve separates the outer insulating layers of the shielded wire cables. The sleeve is encased by an outer insulator that is sealed to the outer insulating layers of the shielded wire cables. A method of splicing shielded wire cables together is also presented.

The abstract of <CIT> states: 'A flat cable includes an enclosure sleeve that encloses a selected section of a cluster section of a flexible substrate. The enclosure sleeve has opposite ends respectively coupled to a first water resistant member and a second water resistant member. Each of the water resistant members includes a base forming a hollow channel and an insertion end extending from the base. The insertion end is fit to an inside wall or an outside wall of an end of the enclosure sleeve. The first water resistant member, the second water resistant member, and the enclosure sleeve are combined together to form a water resistant section arranged at a selected section of the flexible substrate. When the flexible substrate is subjected to a stretching force in an extension direction of the flexible substrate or a torque applied in a rotation direction thereof, the flexible substrate is allowed to undergo relative displacement with respect to the first water resistant member, the second water resistant member, and the enclosure sleeve.

The abstract of <CIT> refers to an assembly intended to be mounted on a structure. The assembly comprises a duct (<NUM>) in the form of a hollow tubular body, with a longitudinal axis, an internal volume of which defines a zone for receiving a bundle of cables, said conduit being flexible and being split along the longitudinal axis. The assembly further comprises at least one fixing lug fixedly secured to the duct, said at least one fixing lug being intended to be assembled to the structure.

According to several aspects, an electrical pass-through assembly as defined in claim <NUM> is disclosed.

In another aspect, an aircraft according to claim <NUM> is disclosed.

In still another aspect, a method of installing an electrical pass-through assembly according to claim <NUM> is disclosed.

The features, functions, and advantages that have been discussed may be achieved independently in various embodiments or may be combined in other embodiments further details of which can be seen with reference to the following description and drawings.

The present disclosure is directed towards an electrical pass-through assembly configured to extend lengthwise through the front spar and the rear spar of an aircraft wing. The electrical pass-through assembly includes a sleeve defining a fixed end, a locked end, a passage extending between the fixed end and the locked end, a mating feature disposed on the fixed end, and a locking feature disposed on the locked end. Both the fixed end and the locked end of the sleeve are sealed to prevent contaminants from entering the sleeve. The electrical pass-through assembly also includes a fitting that is attached to the wing. The fitting is attached to a front spar of the wing. The fitting includes a corresponding mating feature disposed along an inner surface of the fitting that engages with the mating feature disposed at the fixed end of the sleeve to prevent relative rotation between the fitting and the sleeve. The electrical pass-through assembly also includes a locking retainer including a corresponding locking feature that securely engages with the locking feature disposed at the locked end of the sleeve. The electrical pass-through assembly further includes one or more wiring harness sleeves that are secured within the sleeve. The wiring harnesses are secured so as to prevent rotation or translation within the sleeve.

Referring to <FIG>, an electrical pass-through assembly <NUM> that traverses a structure <NUM> is illustrated. In the non-limiting embodiment as shown in <FIG>, the structure <NUM> is represented by an aircraft wing <NUM>. <FIG> illustrates a skeletal structure of the aircraft wing <NUM>, which includes a front spar <NUM>, a rear spar <NUM>, a plurality of ribs <NUM>, and a lower cover <NUM>. The plurality of ribs <NUM> extend between the front spar <NUM> and the rear spar <NUM>. <FIG> is viewed from an aft end <NUM> of the aircraft wing <NUM>. In an example, aircraft wing <NUM> is a composite wing constructed of composite materials. In one embodiment, the aircraft wing <NUM> may be constructed of carbon fiber reinforced plastic (CFRP) materials. The electrical pass-through assembly <NUM> extends lengthwise through respective openings (not visible in <FIG>) in the front spar <NUM> and the rear spar <NUM> of the aircraft wing <NUM>. The electrical pass-through assembly <NUM> secures one or more wiring harnesses <NUM> within a sleeve <NUM>. In an example, the wiring harnesses <NUM> comprise power feeder wires, such as power feeder wires for equipment such as an actuator. It is to be appreciated that the electrical pass-through assembly <NUM> may be located in areas of the aircraft wing <NUM> that may potentially comprise volatile liquid or gases (e.g., fuel vapor), such as an area outboard of a surge fuel tank (not shown) located within the aircraft wing <NUM>. In an example, the area outboard of a surge fuel tank comprises a vapor leakage zone. As explained below, the electrical pass-through assembly <NUM> protects the one or more wiring harnesses <NUM> from the environment within the aircraft wing <NUM>.

Although <FIG> illustrates the structure <NUM> as an aircraft wing, it is to be appreciated that this illustration is merely exemplary in nature. Indeed, the electrical pass-through assembly <NUM> may be used in a variety of other applications and is not limited to an aircraft wing. Specifically, in one embodiment, the electrical pass-through assembly <NUM> may be used to pass high voltage wires through an enclosed space that may potentially comprise volatile liquid or gases (e.g., fuel vapor). One example is a confined area within a facility that produces volatile compounds, such as an oil refinery.

<FIG> illustrates the electrical pass-through assembly <NUM> when viewed from a forward end <NUM> of the aircraft wing <NUM> (<FIG>) and <FIG> is an illustration of the electrical pass-through assembly <NUM> viewed from the aft end <NUM> of the aircraft wing <NUM> (<FIG>). Referring to <FIG> and <FIG> the sleeve <NUM> defines a fixed end <NUM> and a locked end <NUM>. The electrical pass-through assembly <NUM> includes a fitting <NUM> and a locking retainer <NUM>. The fitting <NUM> is disposed at the fixed end <NUM> of the sleeve <NUM>, and the locking retainer <NUM> is securely engaged with the locked end <NUM> of the sleeve <NUM>. It is to be appreciated that both the fixed end <NUM> and the locked end <NUM> of the sleeve <NUM> are sealed respectively by a first dust seal <NUM> (seen in <FIG>) and a second dust seal <NUM> (seen in <FIG>) and a first dust cap <NUM> (seen in <FIG>) and a second dust cap <NUM> (seen in <FIG>).

<FIG> is a perspective view of the sleeve <NUM>. The sleeve <NUM> further defines a passage <NUM> extending between the fixed end <NUM> and the locked end <NUM>, a mating feature <NUM> disposed on the fixed end <NUM>, and a locking feature <NUM> disposed on the locked end <NUM>. The one or more wiring harnesses <NUM> (seen in <FIG>, <FIG> and <FIG>) are received within the passage <NUM> of the sleeve <NUM> and extends along a longitudinal axis A-A of the sleeve <NUM> through both the fixed end <NUM> and the locked end <NUM> of the sleeve <NUM>. As seen in <FIG>, the sleeve <NUM> extends lengthwise through the front spar <NUM> and the rear spar <NUM> of the aircraft wing <NUM>, therefore routing the wiring harnesses <NUM> through the aircraft wing <NUM>. In the embodiment as shown in <FIG>, the sleeve <NUM> includes a tubular profile, however, it is to be appreciated that the sleeve <NUM> may include other geometries as well.

<FIG> is an exploded view of the electrical pass-through assembly <NUM> taken at the fixed end <NUM> of the sleeve <NUM> illustrating the fitting <NUM>, a first retaining ring <NUM>, the first dust seal <NUM>, the first dust cap <NUM>, and a pair of fasteners <NUM>. The first dust seal <NUM> is disposed at the fixed end <NUM> of the sleeve <NUM>. The first retaining ring is constructed of an elongated member <NUM> that is not joined at its respective ends <NUM>, thereby defining a split <NUM>. The first retaining ring <NUM> is secured to the sleeve <NUM> by a plurality of first retaining features <NUM> (also seen in <FIG>) that are part of the sleeve <NUM> and is described in greater detail below.

The first dust seal <NUM> includes one or more openings <NUM> that seal around the one or more wiring harnesses <NUM> (<FIG> and <FIG>) and is split lengthwise along a center portion <NUM> to seal around the one or more wiring harnesses <NUM>. The first dust seal <NUM> and the second dust seal <NUM> (seen in <FIG>) substantially prevent debris from entering the sleeve <NUM>, and are constructed of a flexible material such as, for example, rubber. The first dust cap <NUM> fits over the first dust seal <NUM> and is split into two separate sections 50A, 50B. The first dust cap <NUM> may be constructed of plastic and also prevents debris from entering the sleeve <NUM>. As explained in greater detail and shown in <FIG>, the fasteners <NUM> are used to secure the separate sections 50A, 50B of the first dust cap <NUM> to one another. The two separate sections 50A, 50B of the first dust cap <NUM> define an opening <NUM> for receiving the one or more wiring harnesses <NUM>.

<FIG> is an illustration of the electrical pass-through assembly <NUM> viewed at the front spar <NUM>. The fitting <NUM> is configured to attach the structure <NUM> (<FIG>). Specifically, in the embodiment as shown in the figures, the fitting <NUM> is rigidly attached to the front spar <NUM> of the aircraft wing <NUM> by a plurality of fasteners <NUM> that are received by openings <NUM> (seen in <FIG>) disposed around a flange <NUM> of the fitting <NUM>. Thus, the fixed end <NUM> of the sleeve <NUM> is attached to the front spar <NUM> of the aircraft wing <NUM>. In contrast, the locked end <NUM> of the sleeve <NUM> is not rigidly attached to the aircraft wing <NUM>, and therefore is not subjected to the loads caused by thermal expansion and contraction as well as vibrations that are experienced by the aircraft wing <NUM> during operation. It is to be appreciated that all of the components of the electrical pass-through assembly <NUM> (i.e., the sleeve <NUM>, the fitting <NUM>, the locking retainer <NUM>, the dust seals <NUM>, <NUM>, the dust caps <NUM>, <NUM>, the retaining rings <NUM>, <NUM>, and the wiring harness sleeves <NUM>) except for the fasteners <NUM> (<FIG>) and <NUM> (<FIG>) used to secure the dust caps <NUM>, <NUM> are constructed of nonconductive materials. As a result, attachment between the fitting <NUM> to the front spar <NUM> does not require specialized grounding fasteners.

<FIG> is a perspective view of the fitting <NUM> and <FIG> is an enlarged view of the fixed end <NUM> of the sleeve <NUM>. Referring to <FIG>, the fitting <NUM> includes an inner surface <NUM> defining an opening <NUM>. The opening <NUM> of the fitting <NUM> is shaped to receive the fixed end <NUM> of the sleeve <NUM>. A corresponding mating feature <NUM> is disposed along the inner surface <NUM> of the fitting <NUM> and engages with the mating feature <NUM> disposed at the fixed end <NUM> of the sleeve <NUM> to prevent relative rotation between the fitting <NUM> and the sleeve <NUM>. The fitting <NUM> is rigidly attached to the structure <NUM> (i.e., the front spar <NUM> seen in <FIG>), which in turn secures the fixed end <NUM> of the sleeve <NUM> to the structure <NUM>. As explained below, a lip <NUM> (<FIG>) that circumferentially extends around the outer surface <NUM> of the sleeve <NUM> allows for the sleeve <NUM> to move relative to the fitting <NUM> to account for manufacturing tolerances during assembly.

In the non-limiting embodiment as shown in <FIG>, the mating feature <NUM> disposed on the fixed end <NUM> of the sleeve <NUM> and the corresponding mating feature <NUM> disposed along the inner surface <NUM> of the fitting <NUM> comprise one or more interlocking tabs <NUM>. Specifically, the one or more interlocking tabs <NUM> include a plurality of raised tabs <NUM> disposed along an outer surface <NUM> of the sleeve <NUM>. In the embodiment as shown in <FIG>, the sleeve <NUM> comprises of four raised tabs <NUM> disposed equidistant from one another. The one or more interlocking tabs <NUM> further include a plurality of corresponding recessed tabs <NUM> disposed around the inner surface <NUM> of the fitting <NUM>, where the corresponding recessed tabs <NUM> are shaped to engage with the raised tabs <NUM> disposed around the outer surface <NUM> of the sleeve <NUM>, thereby preventing relative rotation between the sleeve <NUM> and the fitting <NUM>. It is to be appreciated that the one or more interlocking tabs <NUM> shown in <FIG> are exemplary in nature, and any other type of feature for preventing relative rotation between the sleeve <NUM> and the fitting <NUM> may be used as well.

Referring specifically to <FIG>, the fixed end <NUM> of the sleeve <NUM> includes the lip <NUM> that circumferentially extends around the outer surface <NUM> of the sleeve <NUM>. The lip <NUM> is disposed at an end <NUM> of the fixed end <NUM> of the sleeve <NUM>. <FIG> is a cross-sectioned view of the fixed end <NUM> of the sleeve <NUM>. The lip <NUM> of the sleeve <NUM> engages with the inner surface <NUM> of the fitting <NUM>. The interface between the lip <NUM> and the inner surface <NUM> of the fitting <NUM> allows the sleeve <NUM> to move relative to the rear spar <NUM> (<FIG>) during assembly in order to account for manufacturing tolerances between the front spar <NUM> and the rear spar <NUM>. In the exemplary embodiment as shown, the lip <NUM> of the sleeve <NUM> includes a spherical profile <NUM>, however, it is to be appreciated that other geometries may be used as well. In the example as shown in <FIG>, the interface between the spherical profile <NUM> of the lip <NUM> and the inner surface <NUM> of the fitting <NUM> allows for manufacturing tolerance misalignment between the front spar <NUM> and the rear spar <NUM> (<FIG>).

Continuing to refer to <FIG>, the first dust seal <NUM> is disposed at the end <NUM> of the fixed end <NUM> of the sleeve <NUM> and is engaged with a first lip <NUM> disposed circumferentially around the opening <NUM> of the fitting <NUM>. In other words, the first dust seal <NUM> fits over the first lip <NUM> disposed around the opening <NUM> of the fitting <NUM>. The two separate sections 50A, 50B of the first dust cap <NUM> (only the section 50A is shown in <FIG>) are installed over the first dust seal <NUM>. Each of the two separate sections 50A, 50B of the first dust cap <NUM> define a circumferential lip <NUM>. The circumferential lip <NUM> is received by a circumferential groove <NUM> disposed around the fitting <NUM>. Each fastener <NUM> is received by a corresponding opening <NUM> within the section 50A of the first dust cap <NUM> and secures the section 50A with the opposing section 50B (seen in <FIG>) of the first dust cap <NUM>.

<FIG> is an exploded view of the locked end <NUM> of the sleeve <NUM>, where the electrical pass-through assembly <NUM> includes a sealing washer <NUM>, a tensioning member <NUM>, a second retaining ring <NUM>, the locking retainer <NUM>, the second dust seal <NUM>, and the second dust cap <NUM>, and a pair of fasteners <NUM>. In the embodiment as shown in <FIG>, the locked end <NUM> of the sleeve <NUM> is received by an opening (not visible) in the rear spar <NUM>. The sealing washer <NUM> includes an opening (not visible) that is received by the locked end <NUM> of the sleeve <NUM>. The sealing washer <NUM> is an anti-friction sealing washer that is disposed directly adjacent to an outer surface <NUM> of the rear spar <NUM>. The sealing washer <NUM> acts as a physical barrier that protects the outer surface <NUM> of the rear spar <NUM> from abrasions that may occur when the tensioning member <NUM> vibrates during flight. The tensioning member <NUM> defines an opening <NUM> that is received by the locked end <NUM> of the sleeve <NUM> and is placed between the sealing washer <NUM> and the locking retainer <NUM>. In the embodiment as shown in <FIG>, the tensioning member <NUM> is a spring washer or a wave washer.

Similar to the first retaining ring <NUM> seen in <FIG>, the second retaining ring <NUM> is constructed of an elongated member <NUM> that is not joined at its respective ends <NUM>, thereby creating a split <NUM>. The second retaining ring <NUM> is secured to the sleeve <NUM> by a plurality of second retaining features <NUM> that are part of the sleeve <NUM> and is described in greater detail below. The second dust seal <NUM> is disposed on the locking retainer <NUM> of the sleeve <NUM>. The second dust seal <NUM> includes one or more openings <NUM> that seal around the one or more wiring harnesses <NUM> (<FIG>) and is split lengthwise along a center portion <NUM> to seal around the one or more wiring harnesses <NUM>. The second dust cap <NUM> fits over the second dust seal <NUM> and is split into two separate sections 52A, 52B. Similar to the first dust cap <NUM>, the second dust cap <NUM> is also constructed of plastic and prevents debris from entering the sleeve <NUM>. The two separate sections 52A, 52B of the second dust cap <NUM> define an opening <NUM> for receiving the one or more wiring harnesses <NUM>.

The second dust seal <NUM> is disposed at an end <NUM> of the locking retainer <NUM> and is engaged with a second lip <NUM> disposed circumferentially around an opening <NUM> defined by the locking retainer <NUM>. The two separate sections 52A, 52B of the second dust cap <NUM> are installed over the second dust seal <NUM>. Each of the two separate sections 52A, 52B of the second dust cap <NUM> define a circumferential lip <NUM>. The circumferential lip <NUM> is received by a circumferential groove <NUM> disposed around the locking retainer <NUM>. Each fastener <NUM> is received by a corresponding opening <NUM> within the sections 52A, 52B of the second dust cap <NUM> to secure the sections 52A, 52B to one another.

<FIG> is an enlarged view of the locked end <NUM> of the sleeve <NUM> and <FIG> illustrates the locking retainer <NUM>. Referring to <FIG>, the locking retainer <NUM> is securely engaged with the locked end <NUM> of the sleeve <NUM>. An inner surface <NUM> of the locking retainer <NUM> defines the opening <NUM>. The opening <NUM> of the locking retainer <NUM> is shaped to receive the locked end <NUM> of the sleeve <NUM>. The locking retainer <NUM> includes a corresponding locking feature <NUM> disposed around the inner surface <NUM> of the opening <NUM> that securely engages with the locking feature <NUM> disposed at the locked end <NUM> of the sleeve <NUM>.

In the exemplary embodiment as shown in <FIG>, the locking feature <NUM> disposed on the locked end <NUM> of the sleeve <NUM> includes one or more ramped grooves <NUM> that extend around the outer surface <NUM> of the sleeve <NUM> and terminate at a corresponding end stop <NUM>. Referring to <FIG>, the corresponding locking feature <NUM> of the locking retainer <NUM> includes one or more raised posts <NUM> disposed around the inner surface <NUM> of the opening <NUM>, where each raised post <NUM> is configured to lockingly engage with a corresponding end stop <NUM> of one of the ramped grooves <NUM>. When the raised posts <NUM> of the locking retainer <NUM> are engaged with the corresponding end stops <NUM> disposed on the sleeve <NUM>, the locking retainer <NUM> is securely engaged with the locked end <NUM> of the sleeve <NUM>. The tensioning member <NUM> (seen in <FIG>) is configured to provide tension between the locking retainer <NUM> and the structure <NUM>. The tensioning member <NUM> ensures the locking retainer <NUM> stays engaged with the locked end <NUM> of the sleeve <NUM> when the electrical pass-through assembly <NUM> is exposed to vibration and thermal expansion.

In the non-limiting embodiment as shown in <FIG>, the locked end <NUM> of the sleeve <NUM> includes four ramped grooves <NUM> spaced equidistant from one another, and the locking retainer <NUM> includes four corresponding raised posts <NUM> spaced equidistant from one another. It is to be appreciated that the locking feature <NUM> disposed on the sleeve <NUM> shown in <FIG> and the corresponding locking feature <NUM> disposed on the locking retainer <NUM> shown in <FIG> are exemplary in nature, and any other type of feature for secure engagement between the sleeve <NUM> and the locking retainer <NUM> may be used as well.

<FIG> illustrates the electrical pass-through assembly <NUM> when viewed from the locked end <NUM>, where the second dust seal <NUM> and the second dust cap <NUM> (<FIG>) have been removed. The electrical pass-through assembly <NUM> further includes one or more wiring harness sleeves <NUM> that are contained inside the passage <NUM> of the sleeve <NUM>. Each wiring harness sleeve <NUM> includes a passageway <NUM> (<FIG>) configured to contain a corresponding wiring harness <NUM>. In the embodiment as shown in <FIG>, two wiring harness sleeves <NUM> are disposed within the sleeve <NUM>, however, it is to be appreciated that fewer or more wiring harness sleeves <NUM> may be included as part of the electrical pass-through assembly <NUM> depending upon the application.

The two wiring harness sleeves <NUM> are secured within the sleeve <NUM> of the electrical pass-through assembly <NUM> and are interlocked with one another. <FIG> illustrates the two wiring harness sleeves <NUM> before they are interlocked together, and <FIG> illustrates the wiring harness sleeves <NUM> interlocked to one another during assembly. In the embodiment as shown in <FIG>, <FIG>, the one or more wiring harness sleeves <NUM> include of a pair of identical wiring harness sleeves <NUM> that interlock with one another. Each passageway <NUM> of the wiring harness sleeves <NUM> includes a rounded profile <NUM>, an open top <NUM>, and a pair of longitudinally extending hooks <NUM>. Each wiring harness sleeve <NUM> also includes a pair of longitudinally extending tabs <NUM> disposed opposite to the passageway <NUM>. As seen in <FIG>, one of the wiring harness sleeves <NUM> is translated in a longitudinal direction D such that the longitudinally extending tabs <NUM> slidingly engage and interlock with the longitudinally extending tabs <NUM> disposed on the remaining wiring harness sleeve <NUM>.

Turning to <FIG>, once the wiring harness sleeves <NUM> interlock with one another, a corresponding wiring harness <NUM> is placed within the passageway <NUM> of each of the one or more wiring harness sleeves <NUM>. Referring to <FIG>, once the wiring harnesses <NUM> are placed within their respective passageways <NUM>, a sleeve lock <NUM> is slid in the longitudinal direction D over the passageway <NUM> of each of the one or more wiring harness sleeves <NUM>. The sleeve lock <NUM> is configured to retain the wiring harness <NUM> within the respective passageway <NUM> of the wiring harness sleeve <NUM>. Referring to <FIG>, a connector <NUM> is placed on each end <NUM> of the wiring harnesses <NUM> (only one end is shown in <FIG>), and the wiring harnesses <NUM> are then slid through the sleeve <NUM>.

<FIG> illustrates the electrical pass-through assembly <NUM> when viewed from the locked end <NUM> of the sleeve <NUM>, where the second dust seal <NUM>, the second dust cap <NUM>, the second retaining ring <NUM> (<FIG>), and the wiring harnesses <NUM> have been removed (the first retaining ring <NUM> disposed on the fixed end <NUM> of the sleeve <NUM> is still visible). <FIG> is a longitudinal cross-sectioned view of the sleeve <NUM>, where an inner surface <NUM> of the sleeve <NUM>. Referring to <FIG>, the sleeve <NUM> includes one or more pairs of blades <NUM> that extend longitudinally along the inner surface <NUM> of the sleeve <NUM>. Each pair of blades <NUM> corresponds to one of the wiring harness sleeves <NUM>. Thus, in the example as shown in <FIG> and <FIG>, the sleeve <NUM> includes two pairs of blades <NUM> (only one pair of blades <NUM> is visible in <FIG>). As seen in <FIG>, each sleeve lock <NUM> is engaged between one of the pairs of blades <NUM>, where engagement of the sleeve lock <NUM> between the two blades <NUM> prevents relative rotation between the respective wiring harness sleeve <NUM> and the sleeve <NUM>. Specifically, each sleeve lock <NUM> includes a pair of longitudinally extending curved ribs <NUM> that are disposed between a corresponding pair of blades <NUM> of the sleeve <NUM>. Each curved rib <NUM> also defines a longitudinally extending channel <NUM> that is shaped to receive one of the longitudinally extending hooks <NUM> of the corresponding wiring harness sleeves <NUM>.

Referring specifically to <FIG>, each blade <NUM> of the one or more pairs of blades <NUM> includes a first retaining feature <NUM> disposed at the fixed end <NUM> of the sleeve <NUM>. In the exemplary embodiment as shown, the first retaining feature <NUM> is a recess <NUM> shaped to receive a portion of the elongated member <NUM> of the first retaining ring <NUM>. Likewise, as seen in <FIG>, each blade <NUM> also includes a second retaining feature <NUM> disposed at the locked end <NUM> of the sleeve <NUM>, where the retaining feature <NUM> is a recess <NUM> shaped to receive a portion of the elongated member <NUM> of the second retaining ring <NUM>.

Referring to <FIG>, the first retaining ring <NUM> is secured by the first retaining feature <NUM> of each blade <NUM> (only two of the blades <NUM> are visible in <FIG>). The first retaining ring <NUM> abuts against a first end surface <NUM> of the one or more wiring harness sleeves <NUM> to prevent translational movement of the one or more wiring harness sleeves <NUM> within the sleeve <NUM>. Similarly, as seen in <FIG>, the second retaining ring <NUM> engages with the second retaining feature <NUM> of each blade <NUM>. The second retaining ring <NUM> abuts against a second end surface <NUM> of the one or more wiring harness sleeves <NUM> to prevent translational movement of the one or more wiring harness sleeves <NUM> within the sleeve <NUM>.

In another aspect, a method of installing an electrical pass-through assembly <NUM> that traverses a structure <NUM> is provided.

Within examples, the method of installing an electrical pass-through assembly <NUM> that traverses a structure <NUM> includes attaching a fitting <NUM> to the structure <NUM>, wherein the fitting <NUM> includes an inner surface <NUM> defining an opening <NUM>; inserting a sleeve <NUM> within the opening <NUM> of the fitting <NUM>, wherein the sleeve <NUM> includes a fixed end <NUM>, a locked end <NUM>, a passage <NUM> extending between the fixed end <NUM> and the locked end <NUM>, a mating feature <NUM> disposed on the fixed end <NUM>, and a locking feature <NUM> disposed on the locked end <NUM>; engaging the mating feature <NUM> disposed on the fixed end <NUM> of the sleeve <NUM> with a corresponding mating feature <NUM> disposed along the inner surface <NUM> of the fitting <NUM> to prevent relative rotation between the fitting <NUM> and the sleeve <NUM>; securely engaging the locking feature <NUM> disposed on the locked end <NUM> of the sleeve <NUM> with a corresponding locking feature <NUM> that is part of a locking retainer <NUM>; and sliding one or more wiring harness sleeves <NUM> through the sleeve <NUM>, wherein the one or more wiring harness sleeves <NUM> extend along a longitudinal axis of the sleeve <NUM> and extend through both the fixed end <NUM> and the locked end <NUM>.

<FIG> illustrate a process flow diagram illustrating an exemplary method for installing the electrical pass-through assembly <NUM> that traverses the structure <NUM> (shown in <FIG>). Although the steps of the method are described as taking place according to a certain sequence, the described steps may also be performed in another order than the order described herein. It is further understood that certain steps may be performed concurrently, other steps added, or certain steps described herein omitted. Indeed, the descriptions of systems and processes in the present specification are provided for the purpose of illustrating certain embodiments and should in no way be interpreted to limit the subject matter disclosed. Referring now to <FIG>, <FIG>, and <FIG>, method <NUM> begins at block <NUM>. In block <NUM>, the fitting <NUM> is attached to the structure <NUM>. In the exemplary embodiment as shown in the figures, the structure <NUM> is the aircraft wing <NUM>, and the fitting <NUM> is attached to the front spar <NUM> of the aircraft wing <NUM> by the plurality of fasteners <NUM> (seen in <FIG>). The method <NUM> may then proceed to block <NUM>.

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, in block <NUM> the sleeve <NUM> is inserted through the structure <NUM> and within the opening <NUM> of the fitting <NUM> (<FIG>). In the embodiment as shown, the structure <NUM> is the aircraft wing <NUM>, and the sleeve <NUM> is received by openings (not visible in the figures) in the front spar <NUM> and the rear spar <NUM>. The method <NUM> may then proceed to block <NUM>.

Referring to <FIG>, and <FIG>, in block <NUM> the mating feature <NUM> disposed on the fixed end <NUM> of the sleeve <NUM> engages with a corresponding mating feature <NUM> disposed along the inner surface <NUM> of the fitting <NUM> to prevent relative rotation between the fitting <NUM> and the sleeve <NUM>. The method <NUM> may then proceed to block <NUM>.

Referring to <FIG> and <FIG>, in block <NUM> the locked end <NUM> of the sleeve <NUM> is received by an opening (not visible in <FIG>) of the sealing washer <NUM>. The method <NUM> may then proceed to block <NUM>.

In block <NUM>, the locked end <NUM> of the sleeve <NUM> is received by the opening <NUM> of the tensioning member <NUM>. The method <NUM> may then proceed to block <NUM>.

Referring to <FIG>, and <FIG>, in block <NUM> the locking feature <NUM> disposed on the locked end <NUM> of the sleeve <NUM> securely engages with the corresponding locking feature <NUM> of the locking retainer <NUM>. The method <NUM> may then proceed to block <NUM>.

Referring to <FIG> and <FIG>, in block <NUM> the pair of identical wiring harness sleeves <NUM> are interlocked with one another. Specifically, one of the wiring harness sleeves <NUM> is translated in the longitudinal direction D such that the longitudinally extending tabs <NUM> slidingly engage and interlock with the longitudinally extending tabs <NUM> disposed on the remaining wiring harness sleeve <NUM>. The method <NUM> may then proceed to block <NUM>.

Referring to <FIG> and <FIG>, in block <NUM> a wiring harness <NUM> is received within the passageway <NUM> of each of the one or more wiring harness sleeves <NUM>. The method <NUM> may then proceed to block <NUM>.

Referring to <FIG>, and <FIG>, in block <NUM> the sleeve lock <NUM> is slid over the passageway <NUM> of each of the one or more wiring harness sleeves <NUM>. The method <NUM> may then proceed to block <NUM>.

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, in block <NUM> the sleeve lock <NUM> of a corresponding wiring harness sleeve <NUM> is positioned between a pair of blades <NUM> that extend longitudinally along an inner surface <NUM> of the sleeve <NUM>. The method <NUM> may then proceed to block <NUM>.

In block <NUM>, the corresponding wiring harness sleeve <NUM> is slid through the sleeve <NUM>, where the one or more wiring harness sleeves <NUM> extend along the longitudinal axis of the sleeve <NUM> and extend through both the fixed end <NUM> and the locked end <NUM>. The sleeve lock <NUM> is engaged between the pair of blades <NUM> to prevent relative rotation between the wiring harness sleeve <NUM> and the sleeve <NUM>. The method <NUM> may then proceed to block <NUM>.

Referring to <FIG> and <FIG>, in block <NUM> the first retaining ring <NUM> is secured by the first retaining feature <NUM> of each pair of blades <NUM>. The method <NUM> may then proceed to block <NUM>.

Referring to <FIG> and <FIG>, in block <NUM> the second retaining ring <NUM> is secured by the second retaining feature <NUM> of each pair of blades. The method <NUM> may then proceed to block <NUM>.

Referring to <FIG>, <FIG>, and <FIG>, in block <NUM> the first dust seal <NUM> engaged with the first lip <NUM> disposed around the opening <NUM> of the fitting <NUM>. The method <NUM> may then proceed to block <NUM>.

Referring to <FIG> and <FIG>, in block <NUM> the second dust seal <NUM> engages with the second lip <NUM> disposed around the locking retainer <NUM>. The method <NUM> may then proceed to block <NUM>.

Referring to <FIG>, <FIG>, and <FIG>, in block <NUM> the first dust cap <NUM> is installed over the first dust seal <NUM>, and the two separate sections 50A, 50B are secured to one another by the fasteners <NUM>. The method <NUM> may then proceed to block <NUM>.

Referring to <FIG> and <FIG>, in block <NUM> the second dust cap <NUM> is installed over the second dust seal <NUM>, and the two separate sections 52A, 52B are secured to one another by the fasteners <NUM>. The method <NUM> may then terminate.

Referring generally to the figures, the disclosed electrical pass-through assembly provides various technical effects and benefits. Specifically, the electrical pass-through assembly is capable of securing multiple wiring harness in place without using clamps. Moreover, the pass-through assembly either prevents or limits the wiring harnesses from rotating or translating during flight. Since disclosed electrical pass-through assembly includes a fixed end that is attached to the aircraft wing and a locked end that is not rigidly attached to the aircraft wing, the sleeve is not subjected to loads caused by the thermal expansion and contraction as well as vibrations. The disclosed electrical pass-through assembly also provides two layers of protection to the wiring harnesses, which are the sleeve and the wiring harness sleeves. The electrical-pass through assembly enables wiring to be installed in confined areas that can potentially comprise volatile liquid or gases (e.g., fuel vapor). For example, the disclosed electrical pass-through assembly may pass high voltage wires (e.g., power feeder wires) in the area outboard of a surge fuel tank located within an aircraft wing. Finally, it is to be appreciated that the pass-through assembly routes the wiring harnesses through the aircraft wing, between the front spar and the rear spar, and therefore allows for electrical power to be supplied to the outboard wing while maintaining separation on the inboard wing. The disclosed electrical pass-through assembly can therefore help to reduce or limit an amount of power feeder wires that are routed along the front or rear spar.

Claim 1:
An electrical pass-through assembly (<NUM>) configured to extend lengthwise through a front spar and a rear spar of an aircraft wing (<NUM>) comprising:
a sleeve (<NUM>) defining a fixed end (<NUM>), a locked end (<NUM>), a passage (<NUM>) extending between the fixed end (<NUM>) and the locked end (<NUM>), a mating feature (<NUM>) disposed on the fixed end (<NUM>), and a locking feature (<NUM>) disposed on the locked end (<NUM>);
a fitting (<NUM>) configured to attach to the wing (<NUM>), the fitting (<NUM>) including an inner surface (<NUM>) defining an opening (<NUM>) shaped to receive the fixed end (<NUM>) of the sleeve (<NUM>), wherein a corresponding mating feature (<NUM>) is disposed along the inner surface (<NUM>) of the fitting (<NUM>) and engages with the mating feature (<NUM>) disposed at the fixed end (<NUM>) of the sleeve (<NUM>) to prevent relative rotation between the fitting (<NUM>) and the sleeve (<NUM>); and
a locking retainer (<NUM>) including a corresponding locking feature (<NUM>) that securely engages with the locking feature (<NUM>) disposed at the locked end (<NUM>) of the sleeve (<NUM>).