Patent Description:
Fuel line couplings that are presently known in the art for interconnecting fuel tanks do not comply with specific requirements for installation of auxiliary fuel tanks inside the aircraft fuselage since such installation involves the need for the coupling component to exhibit large relative displacements in the event of a crash without causing leakage, fault tolerance lightning protection design and/or a double wall construction with a quick disconnect feature. The current auxiliary tank installation techniques do not comply with all the desired requirements necessary for installation since they use simple metal piping, standard flexible couplings, threaded connections and hoses.

Known proposals in the art include <CIT>, <CIT> and <CIT> (the entire contents of which are hereby expressly incorporated herein by reference). While such prior proposals include fuel line coupling components that address certain issues with the installation and interconnection of auxiliary fuel tanks within an aircraft's fuselage, further improvements are desired. It is towards providing such improvements that the embodiments disclosed herein are directed.

<CIT> discloses a fluid line assembly that includes an outer fluid line and an inner fluid line disposed substantially within the outer fluid line. The inner and outer fluid lines each include a slip joint. In an embodiment of this document, at least one of the slip joints includes a reservoir in communication with the interior of the corresponding fluid line. The reservoir is suitable for receiving fluid from the corresponding fluid line as the fluid line assembly is contracted and expelling fluid into the corresponding fluid line as the fluid line assembly is extended. In another embodiment of this document, the inner and outer fluid lines include a ball joint assembly.

<CIT> discloses a double containment pipe system with an expandable joint. The double containment pipe system may comprise an inner, or carrier, pipe assembly and an outer, or containment, pipe assembly. The expandable joint allows the inner, or carrier, pipe assembly and an outer, or containment, pipe assembly to expand axially independently. Such an expandable joint for a double containment pipe system may be beneficial where the carrier and containment pipe assemblies expand or contract at different rates due to different materials and/or different temperature environments.

<CIT> discloses a fluid line assembly including an outer fluid line and an inner fluid line. The inner and outer fluid lines each include a slip joint. At least one of the slip joints include a variable volume reservoir in communication with the interior of the corresponding fluid line. The reservoir is at least partially defined by a first tube section, a second tube section having an axially extending portion and radially extending portion, and a radially extending piston connected to the first tube section for movement therewith. The at least one slip joint also includes a resiliently compressible conductive member positioned between and in contact with the piston and the radially extending portion of the second tube section to create an electrical path therebetween. The resiliently compressible conductive member is divided into sections, wherein each section is separated from an adjacent section by a spacer member adapted to inhibit contact between the axially extending portion of the second tube section and the resiliently compressible conductive member.

<CIT> discloses a device for connecting pipe ends of double-walled pipes for angle compensation and for length compensation of the relative movements of the double-walled pipes to form a double-walled connector. First and second ball heads are arranged concentrically to each other on the double-walled connector. These are each sealed by ball cages. The ball cages are designed for double-walled connections of the double-walled pipe ends. The sealing function for a double-walled angle compensation and a double-walled length compensation are decoupled from each other in the device proposed according to this document and are therefore optimized.

Advantageous embodiments are described by the dependent claims. Broadly, the embodiments disclosed herein are especially adapted to connect fuel lines in an aircraft, e.g., the fuel lines which fluid-connect an aircraft auxiliary fuel tank(s) to its main fuel tank(s). The coupling component embodiments are structurally adapted to allow relative displacements axially, rotationally and radially between parts and provide a relatively quick-disconnect coupling capability using simple tools. The coupling component also includes effective electrical bonding connection. An aircraft provided with the fuel line coupling component as herein described will also be compliant with survivable crash and lightning strike certification requirements.

According to certain embodiments, the fuel line coupling component includes an outer tubular member having a coaxially aligned pair of outer tubular sections that are coaxially displaceable relative to one another and an inner tubular member which is coaxially sleeved within the outer tubular member so as to define an annular space therebetween, the inner tubular member having a coaxially sleeved pair of inner tubular sections that are coaxially displaceable relative to one another. A pair of terminal end connectors having a journalled connection assembly with the respective opposed distal ends of the outer and inner tubular members are provided which allow simultaneous rotational movements of the outer and inner tubular members about a longitudinal axis thereof and simultaneous radial displacements of outer an inner tubular members relative to a reference plane.

The journalled connection assembly associated with the terminal end connectors may be a ball and socket connection assembly. More specifically, ball segments may be positioned at respective distal terminal ends of the outer and inner tubular members while socket segments may be defined by the terminal end connectors so as to journally receive a respective one of the ball segments.

The terminal end connectors may be flanged to allow connection between and to opposed ends of a fuel line. Further, the terminal end connectors may include at least one (preferably a circumferentially spaced apart series of) radially extending connection lobe.

The terminal end connectors of certain embodiments may include respective electrical bonding straps to electrically bond the terminal end connectors to the outer tubular sections of the outer tubular member. According to the invention, the inner tubular member does include pairs of static brushes to electrically bond the inner tubular sections to the terminal end connectors.

An aircraft may thus be provided with a fuel tank coupling assembly having a pair of fuel tank fittings each adapted to being immovably fixed to a respective fuel tank, and the fuel coupling component as briefly described above having its opposed ends thereof connected to respective ones of the fuel tank fittings. Each of the fuel tank fittings may thus be provided with an opposed pair of C-clamps having one end pivotally connected to the respective fuel tank fitting and an opposite end thereof adapted to being aligned with and removably connected to a respective one of the connection lobes of the terminal end connectors.

Certain embodiments of the fuel tank coupling assembly will be provided a fitting flange associated with each of the fuel tank fittings and a connection flange associated with each of the terminal end connectors and adapted to being adjacently mated with a respective fitting flange of the fuel tank fittings. The coupling assembly may therefore further comprise a pair of band clamps (preferably having a V-shaped cross-section) each circumferentially engaged with and in clamping contact with respective adjacently mated fitting and connection flanges. Each of the band clamps will preferably include a turnbuckle adjustment mechanism to allow each band clamp to be tightened circumferentially so as to clamp the respectively adjacent mated fitting and connection flanges one to one another.

These and other aspects and advantages of the present invention will become more clear after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof.

The disclosed embodiments of the present invention will be better and more completely understood by referring to the following detailed description of exemplary non-limiting illustrative embodiments in conjunction with the drawings of which:.

Accompanying <FIG> schematically depicts a fuel line coupling assembly <NUM> installed so as to fluid-connect an auxiliary fuel tank AFT positioned within the aircraft fuselage AF to a main fuel tank MFT that is provided internally of the aircraft wing (not shown). As is perhaps better shown by <FIG>, the fuel line coupling assembly <NUM> generally includes upper and lower tank fittings <NUM>, <NUM> that are interconnected with a double walled coupling component <NUM> to be described in greater detail below. The upper fitting <NUM> serves to fluid-connect the upper end of the coupling component <NUM> to the main fuel tank MFT while the lower fitting <NUM> serves to fluid-connect the lower end of the tubular coupling component <NUM> to the auxiliary fuel tank AFT. Side ports <NUM>, <NUM> are provided by the lower fitting <NUM> so as to allow fluid-connection with additional auxiliary fuel tanks (not shown) positioned within the aircraft fuselage AF as depicted by arrows A1 and A2, respectively.

In the embodiment depicted, the upper fitting <NUM> is a <NUM>° angled fitting having one end connected to the main fuel tank MFT and an opposite end removably coupled to the upper end <NUM> of the coupling component <NUM>. The upper fitting <NUM> includes a pair of diametrically opposed apertured connection ears <NUM>, <NUM> to which the upper split ends <NUM>, <NUM> of C-clamps <NUM>, <NUM> are pivotally connected by way of bolt/nut assemblies <NUM>, <NUM>, respectively. The opposite split ends <NUM>, <NUM> of the C-clamps <NUM>, <NUM> are adapted to receive respective ones of the radially opposed apertured connection lobes <NUM>-<NUM> associated with the upper end <NUM> of the coupling component <NUM>. An additional pair of radially opposed apertured connection lobes <NUM>-<NUM> that are circumferentially spaced apart by about <NUM>° from the lobes <NUM>-<NUM> to which the C-clamps <NUM>, <NUM> are attached may also be provided at the upper end <NUM> of the coupling component <NUM> to allow ease of positioning and connection of the upper end <NUM> to the upper fitting <NUM>. As can be seen, a pair of quick disconnect pins <NUM>, <NUM> are preferably provided with associated lanyard wires 261a, 262a attached to the bolt/nut assemblies <NUM>, <NUM> so as to allow quick connection/disconnection of the split ends <NUM>, <NUM> of the C-clamps <NUM>, <NUM> with the respective ones of the radially opposed apertured connection lobes <NUM>-<NUM>.

A band clamp <NUM> having a generally V-shaped cross-sectional shape is also preferably provided so as to circumferentially engage the mated flanges 200a and 401a of the upper fitting <NUM> and the upper end <NUM> of the coupling component <NUM>, respectively (see <FIG>, <FIG>, <FIG> and <FIG>). The band clamp <NUM> preferably includes a turnbuckle adjustment mechanism <NUM> to allow the band clamp <NUM> to be tightened circumferentially so as to clamp the mated flanges 200a, 401a one to one another.

As noted previously, the lower fitting <NUM> associated with the auxiliary fuel tank AFT may have opposed coupling ports <NUM>, <NUM> to fluid connect the fitting <NUM> with other auxiliary fuel tanks positioned within the aircraft fuselage (i.e., as noted by arrows A1 and A2). The lower fitting <NUM> has a lower end fluid-connected to the auxiliary fuel tank AFT and an opposite end removably coupled to the lower end <NUM> of the coupling component <NUM>. Similar to the upper fitting <NUM>, the lower fitting <NUM> includes a pair of diametrically opposed apertured connection ears <NUM>, <NUM> to which the lower split ends <NUM>, <NUM> of C-clamps <NUM>, <NUM> are pivotally connected by way of bolt/nut assemblies <NUM>, <NUM>, respectively. The opposite split ends <NUM>, <NUM> of the C-clamps <NUM>, <NUM> are adapted to receive respective ones of the radially opposed apertured connection lobes <NUM>-<NUM> associated with the lower end <NUM> of the coupling component <NUM>. An additional pair of radially opposed apertured connection lobes <NUM>-<NUM> that are circumferentially spaced apart by about <NUM>° from the lobes <NUM>-<NUM> to which the C-clamps <NUM>, <NUM> are respectively connected may also be provided at the lower end <NUM> of the coupling component <NUM> to allow ease of positioning and connection of the lower end <NUM> to the lower fitting <NUM>. As can be seen, a pair of quick disconnect pins <NUM>, <NUM> are preferably provided with associated lanyard wires 361a, 362a attached to the bolt/nut assemblies <NUM>, <NUM> so as to allow quick connection/disconnection of the split ends <NUM>, <NUM> of the C-clamps <NUM>, <NUM> with the respective ones of the radially opposed apertured connection lobes <NUM>-<NUM>.

A band clamp <NUM> having a generally V-shaped cross-sectional shape is also preferably provided so as to circumferentially engage the mated flanges 300a and 402a of the lower fitting <NUM> and the lower end <NUM> of the coupling component <NUM>, respectively (see <FIG>, <FIG>, <FIG> and <FIG>). The band clamp <NUM> preferably includes a turnbuckle adjustment mechanism <NUM> to allow the band clamp <NUM> to be tightened circumferentially so as to clamp the mated flanges 300a, 402a one to one another.

The double walled coupling component <NUM> is shown in greater detail in accompanying <FIG> and includes coaxially positioned rigid outer and inner tubular members <NUM> and <NUM>, respectively, each comprising a telescopically sleeved pair of outer and inner tubular sections 412a, 412b and 414a, 414b, respectively. The proximal terminal ends 412b1, 414b1 of each of the outer and inner tubular sections 412b, 414b are provided with sliding elastomeric O-ring seals 412c, 414c, respectively, so as to provide a fluid-tight seal and allow reciprocal coaxial displacements between the outer and inner tubular sections 412a, 412b and 414a, 414b, respectively, relative to the longitudinal axis AL of the coupling component <NUM>. In such a manner, therefore, both the outer and inner tubular members <NUM>, <NUM>, respectively, are axially displaceable (e.g., about <NUM> +/-) and can therefore simultaneously be telescopically extended/retracted coaxially along the longitudinal axis AL as shown by arrow A3 in <FIG>.

The distal terminal ends 412a2, 412b2 and 414a2, 414ab2 of the outer and inner tubular members <NUM>, <NUM> are journally coupled to flanged terminal end connectors <NUM>, <NUM>, respectively. More specifically, each of the distal terminal ends 412a2, 414a2 of the outer and inner tubular sections 412a, 414a, respectively, is journally coupled to the terminal end connector <NUM> while each of the distal terminal ends 412b2, 414b2 of the outer and inner tubular sections 412b, 414b, respectively, is journally coupled to the terminal end connector <NUM>. The flanged end connectors <NUM>, <NUM> may thus be coupled to the respective upper and lower tank fittings <NUM>, <NUM> as has been described above.

The journaled coupling of the terminal ends 412a2, 412b2 and 414a2, 414b2 to the end connectors <NUM>, <NUM>, respectively, is preferably accomplished by a ball and socket joint structure. In this regard, as is perhaps more clearly shown in <FIG>, the distal terminal ends 412a2, 412b2 terminate in spherical ball segments 412d, 412e while the distal terminal ends 414a2, 414b2 terminate in spherical ball segments 414d, 414e, respectively. Each of the end connectors <NUM>, <NUM> in turn defines spherical socket segments <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM>, <NUM>-<NUM> which journally receive the spherical ball segments 412d, 412e and 414d, 414e, respectively. As is shown in <FIG>, such journaled coupling of the terminal ends 412a2, 412b2 and 414a2, 414b2 to the end connectors <NUM>, <NUM>, respectively, thereby allows the outer and inner tubes <NUM>, <NUM> to collectively rotate <NUM>° about the elongate axis AL as shown by arrow A4 as well as to within limits swivel relative to each of the connectors <NUM>, <NUM> as shown by arrows A5, A6 so as to be capable of radial displacements (e.g., up to about <NUM> +/-) relative to a reference vertical plane PR.

It will be appreciated that in use no fuel will be present within the interior annular space defined between the coaxially aligned outer and inner tubular members <NUM>, <NUM>, respectively. In order to prevent a hydraulic air lock from occurring upon telescopic movement of the coaxially aligned outer and inner tubular members <NUM>, <NUM>, respectively, it is preferred that suitable vent apertures (not shown) be provided so as to establish communication between the exterior ambient atmosphere and the annular space.

Electrical bonding straps <NUM>, <NUM> and <NUM> are provided so as to electrically bond the end connectors <NUM>, <NUM> to the outer tubular sections 412a, 412b, respectively, and thereby establish electrical continuity therebetween. Internal electrical continuity between the end connectors <NUM>, <NUM> and the inner tubular sections 414a, 414b is provided by circumferentially spaced apart static brushes 426a connected to and carried by the inner tubular section 414a and circumferentially spaced apart static brushes 426b attached to the inner tubular section 414b. The bonding straps <NUM>, <NUM>, <NUM> and static brushes 426a, 426b therefore assist in the dissipation of static electricity or sparks that may occur due to lightning induced currents.

Claim 1:
A fuel line coupling component for coupling coaxially aligned first and second fuel lines to allow displacements therebetween, wherein the fuel line coupling component comprises:
an outer tubular member (<NUM>) having a coaxially aligned pair of outer tubular sections (412a, 412b) that are coaxially displaceable relative to one another;
an inner tubular member (<NUM>) which is coaxially sleeved within the outer tubular member (<NUM>) so as to define an annular space therebetween, the inner tubular member (<NUM>) having a coaxially sleeved pair of inner tubular sections (414a, 414b) that are coaxially displaceable relative to one another; and
a pair of terminal end connectors (<NUM>, <NUM>) comprising a journalled connection assembly with the respective opposed distal ends (412a2, 412b2, 414a2, 414b2) of the outer and inner tubular members (<NUM>, <NUM>) to thereby allow simultaneous rotational movements of the outer and inner tubular members (<NUM>, <NUM>) about a longitudinal axis thereof and simultaneous radial displacements of the outer and inner tubular members (<NUM>, <NUM>) relative to a reference plane;
wherein the inner tubular member (<NUM>) comprises pairs of static brushes (426a, 426b) to electrically bond the inner tubular sections (414a, 414b) to the terminal end connectors (<NUM>, <NUM>).