Patent Description:
The manufacturing of composite panels includes laying up fiber-reinforced composite plies on a forming tool. Each of the individual composite plies has a fiber orientation angle in which the fibers are aligned within the ply. The different composite plies can be arranged at various orientations relative to the other plies. Different types of composite plies have different design variables, such as but not limited to material and fiber orientation and ply widths. The composite plies may be oriented and sequenced in an optimal arrangement to provide the optimal structural performance. The number of composite plies and types of materials can vary depending on the expected use of the composite member. The composite plies that are stacked together are then cured to form the composite member.

After curing, the composite member is mounted to a frame that is attached to the inner side of the skin. The current assembly process requires multiple technicians to attach the frame. The process includes forming holes and inserting fasteners at the tie foot locations along the frame. The process also includes applying different forces to the skin during the attachment. Technicians are required to check the tie foot locations and door surround frame for gaps. Once completed, the frames and door surrounds are removed from the skin and shims are installed at the needed locations. The frames and door surround are then re-installed onto the skin to verify gaps and install fasteners. Document <CIT>, in accordance with its abstract, states a component support and mechanization machine, which is comprised of a set of units U. <NUM> to U. n, each of which comprises a collection of arcs that form continuous arc-shaped trajectories along which may be moved a series of telescoping columns, equipped with workheads with double hinge joints and capacitative sensors. The arcs of each unit are mounted on rails and the different units U. <NUM> to U. n are placed on main rails.

Document <CIT>, in accordance with its abstract, states a shape holding fixture that includes a plurality of support units configured to be positioned on a lower surface side of an aircraft panel, and provided at intervals along a one-axis direction, the aircraft panel being held by a holding fixture configured to grip an edge portion of the aircraft panel. A shape holding unit is provided to each of the plurality of support units, including a rod which supports the aircraft panel from the lower surface side of the aircraft panel, and configured to adjust a position where the rod comes into contact with the aircraft panel to support the aircraft panel, corresponding to the shape of the aircraft panel.

Document <CIT>, in accordance with its abstract, states a frame-clamping device having connecting means for connecting frame-clamping device at the first frame of the fuselage. A fixing means for force fitting and friction engaging fixing of first shell and second shell of the fuselage is provided.

Document <CIT>, in accordance with its introductory part, states a platform for the production of half- shell-shaped airframe parts, in particular fuselage parts in the form of a molding system with several multi-part, arranged at intervals in the manner of frames, which support the internal stiffeners and outer skin of the cell part during their assembly.

Document <CIT>, in accordance with its introductory part, states a clamping device having a holding body which passes through the structure to be manufactured in its longitudinal direction and which forms an abutment for the stiffeners and a counter support for the outer skin tension members which pull against the stiffeners. The stiffeners are curved in an arc, they are pressed by the outer skin under the action of the tendons onto their abutments formed by the holding body. Improvements are needed to reduce the amount of manpower required during assembly. This can include systems and methods that reduce the number of fasteners that are needed to be installed during the process and reduce the need to remove and reinstall frames multiple times during the process.

One aspect is directed to a device to assemble a skin and a frame of an aircraft fuselage. The device comprises first and second base members that extend along opposing sides of a gap. A plurality of arches are spaced apart and fixedly connected to the first and second base members and that extend across the gap. A strongback is attached to and movable along the first and second base members with the strongback comprising a curved shape that matches the plurality of arches. The strongback further comprises clamps configured to engage with the frame. First and second tension devices apply tension to the skin at the strongback.

In another aspect, fingers are positioned along each of the arches with each of the fingers comprising a body that is connected to one of the arches and an enlarged head at an end of the body and configured to contact against the skin.

In another aspect, each of the arches comprises a central section centered on an apex and lateral sections positioned on each side of the central section with the fingers of the arches along the central section having a fixed position and the fingers of the arches along the lateral sections being movable relative to the arches.

In another aspect, a first indexing member is connected to a first one of the arches at a first end of the first and second base members and a second indexing member is connected to a second one of the arches at a second end of the first and second base members with each of the first and second indexing members comprising a head aligned at an apex of the arch to connect to the skin and align the skin relative to the first and second base members and the arches.

In another aspect, each of the tension devices comprises an arm configured to be attached to the skin with a cylinder to apply a force to the arm and a sensor to sense the amount of force applied to the skin.

In another aspect, a control unit comprising processing circuitry is configured to receive signals from the sensors and control the forces applied to the skin by the first and second tension devices. One aspect is directed to a method of assembling a skin and a frame of an aircraft fuselage. The method comprises: aligning the skin on a support platform and contacting the support platform against the skin at a first number of points; attaching the frame to the skin at limited points along the frame; moving a strongback along the support platform and engaging the strongback to the frame; reducing the contact between the skin and the support platform; and while the contact is reduced, applying tension to the skin at the frame.

In another aspect, aligning the skin on the support platform comprises connecting a leading edge of the skin to a first indexing member at a first end of the support platform and a connecting a trailing edge of the skin to a second indexing member at a second end of the support platform.

In another aspect, attaching the frame to the skin at the limited points along the frame comprises attaching an apex of the frame to the skin at a first point and lateral sides of the frame to the skin at second and third points and with a remainder of the frame being unattached to the skin.

In another aspect, the method further comprises detaching the lateral sides of the frame from the skin at the second and third points after engaging the strongback to the frame and prior to applying the tension to the skin.

In another aspect, the method further comprises engaging the strongback to the frame while the frame is attached to the skin at the limited points.

In another aspect, the method further comprises extending fingers of the support platform into contact with the skin; engaging the strongback to the frame while the fingers are in contact with the skin; and retracting the fingers away from the skin and then applying the tension to the skin.

In another aspect, the method further comprises applying the tension to the skin while the skin is attached to the frame at just a single connector at an apex of the frame.

In another aspect, applying the tension to the skin at the frame comprises applying the tension at sides of the skin.

One aspect is directed to a method of assembling a skin and a frame of an aircraft fuselage with the method comprising: aligning the skin relative to a support platform with the skin comprising an arched shaped with a midpoint and opposing lateral sides that terminate at an outer edge; supporting the skin at arches that are spaced apart along a length of the support platform; securing the skin to the frame with connectors at the midpoint and at each of the lateral sides; translating a strongback that is secured to the support platform along the support platform and into contact with the frame; engaging the strongback with the frame; after engaging the frame, removing the connectors at the lateral sides; and applying tension to the skin at the lateral sides of the skin with the tension being applied at the frame.

In another aspect, the method further comprises applying the tension to the skin at just the frame. In another aspect, aligning the skin relative to the support platform comprises connecting a first tab on a forward end of the skin to a first one of the arches on the support platform and connecting a second tab on a rear end of the skin to a second one of the arches on the support platform.

In another aspect, engaging the strongback with the frame comprises engaging clamps on the strongback to the frame.

In another aspect, the method further comprises securing the skin to the frame at just an apex of the frame while applying the tension to the skin.

In another aspect, the method further comprises securing the strongback to the support platform after engaging the strongback with the frame and prior to applying the tension.

Composite panels can be used to construct a variety of different products. <FIG> illustrates one example of an aircraft <NUM> with a fuselage <NUM> constructed from a number of composite panels <NUM>. The panels <NUM> can include a variety of different shapes and sizes. The panels <NUM> are individually constructed as part of the overall assembly process. Once constructed, the panels <NUM> are connected together to form the fuselage <NUM> of the aircraft <NUM>.

The panels <NUM> include a skin <NUM> that is formed by the composite members. The panels <NUM> also include frames <NUM> attached to the inner side that support the skin. The number and positioning of the frames <NUM> can vary depending up the object that is being formed and the context in which the object is used.

<FIG> illustrates a skin <NUM> formed by composite members and then cured. The composite members include one or more layers of fibers that are pre-impregnated with one or more of a thermoset and thermoplastic matrix resin (e.g., prepreg). The fibers can be formed from a variety of materials, including but not limited to aramids, polyolefins, metal, glass, carbon, boron, ceramic, mineral, and combinations. The fibers are pre-impregnated with a thermoset or thermoplastic matrix resin (e.g., prepreg). In another example, the matrix resin includes a hybrid system of both thermoset and thermoplastic. The matrix resin can be formed from a variety of substances, including but not limited to acrylics, fluorocarbons, polyamides (PA), polyethylenes (PE) such as polyethylene terephthalate (PET), polyesters, polypropylenes (PP), polycarbonates (PC), polyurethanes (PU), polyetheretherketones (PEEK), polyetherketoneketones (PEKK), polyetherimides (PEI), and other material compositions. The different types of composite plies can include a variety of thicknesses. Examples of thicknesses for each of the composite plies includes but are not limited to between about <NUM>,<NUM>-<NUM>,<NUM> (i.e., about <NUM>-<NUM> inches). The skin <NUM> can include various numbers of layers of composite plies. Further, the fibers of one or more of the layers can be oriented in various arrangements (e.g., parallel to each other) depending upon the desired functional requirements of the panel <NUM>.

The skin <NUM> used for the fuselage <NUM> has an arced shape as illustrated in <FIG>. This shape includes an overall curvature with a midpoint M that is equally spaced away from side edges <NUM>. In one example as illustrate in <FIG>, the panel <NUM> includes a curved shape with a radius R1 from a centerline C/L. The size of the skin <NUM> and extent of the arc can vary. In one example, the arc extends about <NUM> degrees (i.e., hemispherical shape). In another example, the arc extends about <NUM> degrees. Other examples can include various smaller or larger sizes. The panel <NUM> further includes an inner side <NUM> and an opposing outer side <NUM>.

After formation, the skin <NUM> is placed on a support platform <NUM> and tensioned. One example of a support platform <NUM> is illustrated in <FIG> and includes a pair of base members <NUM>, <NUM> that are spaced apart by a gap <NUM>. Each of the base members <NUM>, <NUM> includes an elongated shape that is substantially straight. One or more braces <NUM> extend across the gap <NUM> and connect to the base members <NUM>, <NUM> to strengthen the support platform <NUM>.

Arches <NUM> are spaced apart and connected to the base members <NUM>, <NUM> along the length. The arches <NUM> include a first end <NUM> fixedly connected to the first base member <NUM> and an opposing second end <NUM> fixedly connected to the second base member <NUM>. The arches <NUM> are fixed in position along the length of the base members <NUM>, <NUM>. The number of arches <NUM> along the length and the spacing of the arches <NUM> along the length can vary. In one example, the arches <NUM> are equally spaced along the length. In one example, two of the arches <NUM> are positioned at the longitudinal ends of each of the base members <NUM>, <NUM>. As illustrated in <FIG>, a first arch <NUM> is at the first end of the base members <NUM>, <NUM> and a second arch <NUM> is at the second end. In one example, each of the arches <NUM> of the support platform <NUM> includes the same shape and size. Other examples include variations in one or more of the arches <NUM>.

The arches <NUM> have a curved shape that matches the curvature of the skin <NUM>. <FIG> schematically illustrates an arch <NUM> having a curved shape that terminates at the ends <NUM>, <NUM>. The arch <NUM> includes a radius R2. In one example, the radius R2 is equal to the radius R1 of the skin <NUM>. The arch <NUM> includes an apex <NUM> which in this example is at a midpoint between the ends <NUM>, <NUM>. The arch <NUM> can be divided into different sections that include a central section A that extends outward equal amounts from each side of the apex <NUM>. The arch <NUM> also includes lateral sections B, C on opposing sides of the central section A. The sizes of each of these sections can vary depending upon the context.

The arches <NUM> are configured to support the skin <NUM> when the skin <NUM> is placed onto the support platform <NUM>. Fingers <NUM> are connected to the arches <NUM> and extend outward beyond the arches <NUM> to contact against and support the skin <NUM>. Some of the fingers <NUM> are adjustable relative to the arch <NUM> to which they are attached, with other fingers <NUM> being fixedly positioned relative to the arch <NUM> to which they are attached. In one example, the fingers <NUM> positioned along the central section A are fixed and the fingers <NUM> along the lateral sections B, C are adjustable.

<FIG> illustrates a section of an arch <NUM> that includes fingers <NUM>. The fingers <NUM> are fixedly attached relative to the arch <NUM> and include a body <NUM> that is connected to the arch <NUM> with one or more fasteners. A head <NUM> is positioned at the end of the body <NUM> and includes an enlarged size to contact against the skin <NUM>. In one example, these non-movable fingers <NUM> are attached to the arch <NUM> along the central section A.

<FIG> illustrates fingers <NUM> that are movably attached to the arch <NUM>. The fingers <NUM> includes a receptacle <NUM> that supports the body <NUM>. In one example, the fingers <NUM> are manually adjustable such as through a ratcheting mechanism that includes a tab that engages with teeth that extend along the body <NUM>. In another example, the fingers <NUM> are powered by a pneumatic system that includes a cylinder in the body <NUM>. In one example, the positioning of the fingers <NUM> is controlled by a control unit <NUM>. In one example, these movable fingers <NUM> are attached to the arch <NUM> along the lateral sections B, C.

The support platform <NUM> also includes one or more indexing members <NUM> to align the panel <NUM> relative to the support platform <NUM>. In one example as illustrated in <FIG>, indexing members <NUM> are positioned on the outer arches <NUM> (i.e., a first aft arch and a second fore arch). As illustrated in <FIG>, the indexing member <NUM> includes a body <NUM> and an enlarged head <NUM>. In one example, the head <NUM> is aligned with the apex <NUM> of the arch <NUM>. The body <NUM> can be supported in a receptacle <NUM> that provides for adjusting the position of the head <NUM>. In one example, the receptacle <NUM> includes a fastener that engages with the body <NUM> and with the fastener being rotatable to provide for adjusting the position of the head <NUM>. In one example, the panel <NUM> includes a tab on the front and back edges that engage with the indexing members <NUM> when the panel <NUM> is positioned on the support platform <NUM>.

One or more strongbacks <NUM> are positioned on the support platform <NUM>. The strongback <NUM> is configured to support a frame <NUM> that is initially attached to the skin <NUM> during the application of the tensioning force. The strongback <NUM> is movable along the support platform <NUM> to individually support the various frames <NUM> that are attached to the skin <NUM> during the assembly process.

As illustrated in <FIG>, the strongback <NUM> includes a curved shape with a first end <NUM> that is attached to the base member <NUM> and a second end <NUM> that is attached to the base member <NUM>. The curved shape corresponds to the shape of the skin <NUM>. In one example, the curved shape has a radius that matches the radius of one or more of the skin <NUM> and arches <NUM> (i.e., one or more of R1 and R2). The strongback <NUM> is movable along the length of the base members <NUM>, <NUM>. In one example, the ends <NUM>, <NUM> engage directly with rails <NUM> (<FIG>) that extend along one of the base members <NUM> and provides for the translating movement. In one example as illustrated in <FIG>, each end <NUM>, <NUM> is connected to a boot <NUM>. One or more carriages <NUM> positioned on the bottom of the boot <NUM> are configured to engage with a rail <NUM> that extends along the base member <NUM>, <NUM>. In one example, the carriages <NUM> include extensions that ride within slots <NUM> on the lateral sides of the rail <NUM>.

One or more stops <NUM> are mounted to the base member <NUM> to control the translating movement of the strongback <NUM>. The stops <NUM> include a body that is mounted to the base member <NUM> and includes an exposed slot <NUM>. The slot <NUM> is sized to receive a rod <NUM> that extends from the strongback <NUM>. The position of the rod <NUM> within the slot <NUM> can be adjusted to adjust the relative position of the strongback <NUM> along the base member <NUM>. <FIG> includes the rod <NUM> being threaded and with one or more members <NUM> mounted on the threads. Rotation of the members <NUM> adjusts their position along the length of the rod <NUM> and hence moves the strongback <NUM>. <FIG> illustrates the strongback <NUM> with a single rod <NUM> that engages with a stop <NUM>. In another example, a second rod extends from the strongback <NUM> and engages with the second stop <NUM> (i.e., the rear stop <NUM> as illustrated in <FIG> illustrates one end <NUM> of the strongback <NUM> engaged with the base member <NUM>. The second end <NUM> can be mounted to the base member <NUM> in a similar manner.

The strongback <NUM> is configured to engage with and support the frame <NUM>. The strongback <NUM> includes actuators <NUM> that are connected to clamps <NUM> that extend along the length of the strongback <NUM>. The actuators <NUM> can be controlled/positioned to position the clamps <NUM> between a disengaged position that is not engaged with the frame <NUM> and an engaged position that is secured to the frame <NUM>. In one example, the actuators <NUM> are pneumatically controlled to move between engaged and disengaged positions. In another example, the actuators <NUM> include manual adjustments, such as a lever mechanism or fasteners that move the contact members <NUM> between the engaged and disengaged position. <FIG> illustrates the actuators <NUM> in the engaged position with the clamps <NUM> secured to the frame <NUM> that is being supported by the strongback <NUM>.

As illustrated in <FIG>, tensioning devices <NUM> apply a tensioning force to the skin <NUM> when the skin <NUM> is aligned on the support platform <NUM>. In one example, a pair of tensioning devices <NUM> are positioned at the strongback <NUM> to apply tensioning simultaneously to opposing side edges <NUM> of the skin <NUM>. The tensioning device <NUM> is connected to the skin <NUM> by a bracket <NUM> that is mounted at the side edges <NUM>. The bracket <NUM> includes a pair of opposing plates that are clamped with one or more fasteners onto the skin <NUM>. An arm <NUM> extends between and connects to the bracket <NUM> and a pneumatic cylinder <NUM>. The arm <NUM> can be a single member, or multiple separate members that are operatively connected together. The pneumatic cylinder <NUM> is mounted to the base member <NUM> or strongback <NUM> and applies a force to the arm <NUM> through a lever arm <NUM> that applies the tension to the skin <NUM>. In one example, the pneumatic cylinder <NUM> is mounted to the arm <NUM> through a separate lever arm. A sensor <NUM>, such as a load cell, senses an amount of force that is being applied to the skin <NUM>. In one example, the force is referred to a waterline tension force because the force is applied to the side edges <NUM> of the skin <NUM>. The force is applied in a downward direction away from the midpoint M of the skin that is aligned at the apex <NUM> of the arches <NUM>. In one example, the cylinder <NUM> is connected to an air supply that provide air to control the applied forces.

<FIG> illustrates a method of applying a tensioning force to the skin <NUM> to assemble the skin <NUM> and frame <NUM>. The method includes aligning the skin <NUM> on the support platform <NUM> (block <NUM>). The frame is attached to the skin at limited point along the length of the frame <NUM> (block <NUM>). The strongback <NUM> is moved along the support platform <NUM> and engages with the frame <NUM> (block <NUM>). Once the strongback <NUM> is engaged, the amount of contact with the skin <NUM> is reduced (block <NUM>). The tension force is then applied to the skin <NUM> at the frame <NUM> (block <NUM>).

The assembly of the panel <NUM> can include attachment of a single frame <NUM> or can include attachment of multiple frames <NUM>. For multiple frames <NUM>, the separate frames <NUM> are attached individually during separate steps of the total assembly process. These multiple steps can include the same strongback <NUM> used to support the different frames <NUM> and/or two or more strongbacks <NUM> used to support the different frames <NUM> at the different locations.

<FIG> illustrate more detailed steps of the process of forming the panel <NUM> by attachment of the frame <NUM> and tensioning the skin <NUM>. As illustrated in <FIG>, the skin <NUM> is positioned on the support platform <NUM>. Prior to positioning the skin <NUM> on the support platform <NUM>, the fingers <NUM> on the arches <NUM> along the lateral sections B, C are retracted. The fingers <NUM> along the central section A remain extended. The skin <NUM> is positioned on the support platform <NUM> and aligned through the indexing members <NUM> on the support platform <NUM>. In the example of <FIG>, the indexing members <NUM> are positioned at the forward and aft arches <NUM>. In one example as illustrated in <FIG>, the skin <NUM> includes tabs <NUM> that extend outward from the forward and aft ends <NUM> at the midpoint M. Each of the tabs <NUM> is sized to extend over the head <NUM> of the indexing member <NUM>. This positioning aligns the skin <NUM> relative to the support platform <NUM>.

After the skin <NUM> is aligned with the indexing members <NUM>, the fingers <NUM> along the lateral sections B, C are extended to contact against the inner side <NUM> of the skin <NUM>. Thus the fingers <NUM> along each of the sections A, B, C are extended to contact against and support the skin <NUM>.

One or more points along the sides <NUM> of the skin <NUM> can be secured to the support platform <NUM> with clamps <NUM>. Each of the clamps <NUM> is mounted to the skin <NUM> at the side <NUM> and connect to anchors <NUM> on one of the base members <NUM>, <NUM> (see <FIG>). In one example as illustrated in <FIG>, clamps <NUM> secure the skin <NUM> to the base member <NUM> at a door cutout <NUM>.

With the skin supported by the support platform <NUM>, the strongback <NUM> is able to move along the base members <NUM>, <NUM>. In one example, each strongback <NUM> is configured to move along the length between adjacent arches <NUM>. In another example, the strongback <NUM> is able to move past the arches <NUM> and thus can move along the entire length of the skin <NUM>.

After the skin <NUM> is aligned on the support platform <NUM>, a frame <NUM> is aligned along the inner side <NUM> of the skin <NUM> as illustrated in <FIG>. The frame <NUM> is positioned on the inner side <NUM> of the skin <NUM>. In one example, the frame <NUM> is a single, unitary construction that extends between opposing sides <NUM> of the panel <NUM>. The frame <NUM> may extend to and be aligned with the side edges <NUM> or may be positioned inward from the side edges <NUM>. The frame <NUM> includes an arched shape that substantially matches the shape of the arches <NUM> and strongback <NUM>.

The frame <NUM> is initially positioned away from the strongback <NUM>. With the frame <NUM> positioned, the skin <NUM> is attached to the frame <NUM> at a limited number of points. In one example, the frame <NUM> is connected to the skin <NUM> with connectors <NUM> at three points. A first connector <NUM> attaches the skin <NUM> to the frame <NUM> at the midpoint M of the skin <NUM>. Connectors <NUM> further attach the skin <NUM> to the frame <NUM> along each of the lateral sides. The connectors <NUM> provide for temporary connection of the frame <NUM> to the skin <NUM>. In one example, the connectors <NUM> are CLECO connectors available from Apex Tool Group. Various other types of removable connectors may also be used for the connections.

As illustrated in <FIG>, the process continues with the strongback <NUM> translated along the base members <NUM>, <NUM> and into engagement with the frame <NUM>. The clamps <NUM> on the strongback <NUM> are engaged and connect to the frame <NUM>. The strongback <NUM> is further locked in position along the base members <NUM>, <NUM>. In one example, this locking includes securing one or more of the stops <NUM> on the strongback <NUM> that provide the relative positioning with the base members <NUM>, <NUM>. After the strongback <NUM> is engaged with the frame <NUM> and locked in position, the connectors <NUM> along the lateral sections are removed. The connector <NUM> at the midpoint M remains to connect the skin <NUM> to the frame <NUM>.

At this point in the process, the skin <NUM> is supported at each of the arches <NUM>, at the frame <NUM>, and at the lower side edges <NUM> at the door cutout <NUM>. The skin <NUM> remains engaged with each of the indexing members <NUM> at the outer ends of the support platform <NUM>.

The retractable fingers <NUM> on some of the arches <NUM> are retracted away from the skin <NUM>. In one example, this includes retracting the retractable fingers <NUM> along each of the arches except for an end arch <NUM>. The non-retractable fingers <NUM> of the arches <NUM> remain in contact with the skin <NUM>. This includes contact of the fingers <NUM> along the central section of the skin <NUM> at the midpoint M of the skin <NUM>. In one example, the retractable fingers <NUM> adjacent to and forward from the door cutout <NUM> along the arch <NUM> are extended and contact against the skin <NUM>. The frame <NUM> continues to be secured to the strongback <NUM> by the clamps <NUM>. In one example as illustrated in <FIG>, the clamps <NUM> at the door cutout <NUM> are removed.

Tension is then applied to the skin <NUM> as illustrated in <FIG>. Tension devices <NUM> are attached to each of the sides <NUM> of the skin <NUM> at the frame <NUM> and at the strongback <NUM>. The connector <NUM> at the midpoint M remains attached while the tension forces are applied. Further, the frame <NUM> is held in place by the strongback <NUM> while the tension forces T are applied. The tensioning devices <NUM> can incrementally apply the tension forces T. In one example, the amount of tension force T applied to each side edge <NUM> is up to about <NUM>,<NUM> (i.e., about <NUM> lbs).

As illustrated in <FIG>, the tensioning forces are applied in a downward direction T. This force is applied away from the connector <NUM> at the top of the skin <NUM>. The tensioning force provides for the skin <NUM> to conform to the frame <NUM> and reduce or eliminate gaps that could form.

In one example, a control unit <NUM> controls the overall operation of application of the tension forces to the skin <NUM> by the tension devices <NUM>. The control unit <NUM> can be positioned at the support platform <NUM> or can be positioned remotely away from the support platform <NUM>. As illustrated in <FIG>, the control unit <NUM> includes a control circuit <NUM> and a memory circuit <NUM>. The control circuit <NUM> controls the overall operation according to program instructions <NUM> stored in the memory circuit <NUM>. The control circuit <NUM> can include one or more circuits, microcontrollers, microprocessors, hardware, or a combination thereof. Memory circuit <NUM> includes a non-transitory computer readable storage medium storing program instructions <NUM>, such as a computer program product, that configures the control circuit <NUM> to implement one or more of the techniques discussed herein. Memory circuit <NUM> can include various memory devices such as, for example, read-only memory, and flash memory. Memory circuit <NUM> can be a separate component as illustrated in <FIG> or can be incorporated with the control circuit <NUM>. Alternatively, the control circuit <NUM> can omit the memory circuit <NUM>, e.g., according to at least some embodiments in which the control circuit <NUM> is dedicated and non-programmable.

The control unit <NUM> is configured to provide for communication functionality for an operator who is performing the process. Communications can include both incoming and outgoing communications. A communications circuit <NUM> provides for this communication functionality. The communications circuit <NUM> enables communication between user devices and remote entities over a communication network.

In one example, control commands are entered remotely through the communication circuit <NUM>. Additionally or alternatively, the control unit <NUM> includes a user interface <NUM> to control one or more aspects of the tensioning process. The user interface <NUM> can include one or more input devices <NUM> such as but not limited to a keypad, touchpad, roller ball, and joystick. The one or more input devices <NUM> provide for the user to enter commands to the control circuit <NUM>. The user interface <NUM> can also include one or more displays <NUM> for displaying information.

One or more sensors <NUM> detect different aspects of the process. The data from the one or more sensors <NUM> can be stored in the memory circuit <NUM>. One or more sensors <NUM> detect the physical amount of force that is being applied by the tension device <NUM>. One or more sensors <NUM> can detect forces exerted on the skin <NUM> and can include but are not limited to one or more strain gauges and pressure sensors. In one example, the sensor <NUM> is a load cell. A power source <NUM> provides power to the control unit <NUM>. The power source <NUM> can include various configurations, including but not limited to batteries.

After the tension has been applied to the skin <NUM> at the frame <NUM>, the skin <NUM> can be tensioned at one or more additional locations. In one example, the next tensioning process is applied to a different location along the length of the skin <NUM> and using a different strongback <NUM>. In another example, the same strongback <NUM> is used and includes the strongback <NUM> being detached from the frame <NUM> at the first location, moved to a second location along the skin <NUM>, and used to position and support a second frame <NUM>.

In one example, the control circuit <NUM> receives inputs from sensors <NUM> associated with the tensioning devices <NUM> on the opposing sides of the skin <NUM>. The control circuit <NUM> adjusts the forces applied by the tension devices <NUM> on the opposing sides of the skin <NUM> to balance the waterline tension (i.e., balance the forces applied to the left and right sides of the skin <NUM>). The control circuit <NUM> receives inputs from sensors <NUM> that detect the applied tension to the skin to adjust the tensioning as necessary. In one example, the control unit <NUM> controls the inputs to the air cylinders <NUM> on the opposing sides to adjust the tensioning and provide for the tensioning to be self-balancing.

After the tensioning of the skin <NUM>, the frame <NUM> can be permanently attached to the skin <NUM>. The permanent attachment can occur through one or more fasteners and adhesives. In one example, the attachment can occur prior to additional tensioning of the skin <NUM> at different locations along the length. In another example, the skin <NUM> is tensioned at multiple locations and then the frames <NUM> are applied.

The examples described above are directed to a fuselage <NUM> for an aircraft. The tensioning process can also be used to make other members for a wide variety of vehicles. Examples of vehicles include but are not limited to unmanned aircraft, manned spacecraft, unmanned spacecraft, manned rotorcraft, unmanned rotorcraft, satellites, rockets, missiles, manned terrestrial aircraft, unmanned terrestrial aircraft, manned surface water borne aircraft, unmanned surface water borne aircraft, manned sub-surface water borne aircraft, unmanned sub-surface water borne aircraft, automobiles, and trucks, and combinations thereof.

By the term "substantially" with reference to amounts or measurement values, it is meant that the recited characteristic, parameter, or value need not be achieved exactly. Rather, deviations or variations, including, for example, tolerances, measurement error, measurement accuracy limitations, and other factors known to those skilled in the art, may occur in amounts that do not preclude the effect that the characteristic was intended to provide. Furthermore, where a certain quantity is indicated both in SI system and in United States customary units and doubts arise as to the correct numeric value, the United States customary units shall prevail.

Claim 1:
A device to assemble a skin (<NUM>) and a frame (<NUM>) of an aircraft fuselage (<NUM>), the device comprising:
a support platform (<NUM>);
first and second base members (<NUM>, <NUM>) that extend along opposing sides of a gap (<NUM>), said first and second base members (<NUM>, <NUM>) being part of the support platform (<NUM>);
a plurality of arches (<NUM>) that are spaced apart and fixedly connected to the first and second base members (<NUM>, <NUM>) and that extend across the gap (<NUM>), said plurality of arches (<NUM>) being part of the support platform (<NUM>);
a strongback (<NUM>) that is attached to and movable along the first and second base members (<NUM>, <NUM>), the strongback (<NUM>) comprising a curved shape that matches the plurality of arches (<NUM>), the strongback (<NUM>) further comprising clamps (<NUM>) configured to engage with the frame (<NUM>);
first and second tension devices (<NUM>) configured to apply waterline tension force to side edges (<NUM>) of the skin (<NUM>) at the strongback (<NUM>); and
fingers (<NUM>) positioned along each of the arches (<NUM>) and extending outward beyond the arches (<NUM>) to contact against and support the skin (<NUM>), each of the fingers (<NUM>) comprising a body (<NUM>) that is connected to one of the arches and an enlarged head (<NUM>) at an end of the body (<NUM>) and configured to contact against the skin (<NUM>);
wherein each of the arches (<NUM>) comprises a central section centered on an apex (<NUM>) and lateral sections positioned on each side of the central section, the fingers (<NUM>) of the arches (<NUM>) along the central section having a fixed position and the fingers (<NUM>) of the arches along the lateral sections being movable relative to the arches (<NUM>).