Patent Description:
Current veneer panels may include a backer substrate, such as wood, and may thus be susceptible to tearing, wrinkling, and curling. For example, veneer panels may include one or more veneer ply coupled to a poplar backer. The backer, usually wood, on the decorative surface of the veneer may experience warping, separation, or other undesirable cosmetic effects. Many existing veneer panels may not be useable in aerospace applications due to limitations such as conformance with flammability regulations and conformance with customer specifications for the veneer panels. Veneer panels are disclosed in <CIT> and <CIT>.

The object of the invention is achieved with the features of the independent claims.

Embodiments of the invention are specified in the dependent claims.

Disclosed
is a panel assembly for use in an aircraft as defined by claim <NUM>.

In an embodiment, the backing layer may include at least two plies of a wood material and is treated by submerging the backing layer into a water-based fire retardant.

In an embodiment, the face layer has a face thickness between <NUM> inches (. <NUM> millimeters) and. <NUM> inches (<NUM> millimeters).

In an embodiment, the thermoset dry film adhesive has an adhesive thickness of between. <NUM> inches (. <NUM> millimeters) and <NUM> inches (. <NUM> millimeters).

In an embodiment, the panel assembly satisfies requirements set forth in Federal Aviation Regulations (FAR) Section <NUM>.

Also disclosed is a method of forming a panel assembly for use in an aircraft as defined by claim <NUM>.

An embodiment may further include obtaining or forming a second veneer panel and an aviation honeycomb layer having a first surface and a second surface, and coupling the first veneer panel to the first surface of the aviation honeycomb layer and coupling the second veneer panel to the second surface of the aviation honeycomb layer to form the panel assembly.

In an embodiment, the face layer has a face thickness between <NUM> inches (. <NUM> millimeters) and. <NUM> inches (<NUM> millimeters), and the thermoset dry film adhesive has an adhesive thickness of between. <NUM> inches (. <NUM> millimeters) and <NUM> inches (. <NUM> millimeters).

In an embodiment, the backing layer may include at least two plies of a wood material.

The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the exemplary embodiments of the disclosure, it should be understood that other embodiments may be realized and that logical changes and adaptations in design and construction may be made in accordance with this disclosure and the teachings herein. Thus, the detailed description herein is presented for purposes of illustration only and not limitation.

Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Surface shading lines may be used throughout the figures to denote different parts but not necessarily to denote the same or different materials.

Referring now to <FIG>, an aircraft interior <NUM> of an aircraft <NUM> may include multiple panel assemblies <NUM>. Each of the panel assemblies <NUM> may be designed for use in the aircraft <NUM>. For example, the panel assemblies <NUM> may be used to form cabinets, doors, or other structures within the aircraft <NUM>. In that regard, the panel assemblies <NUM> may be designed to satisfy the requirements set forth in Federal Aviation Regulations (FAR) Section <NUM>. This Section sets forth that materials used in the construction of interiors of aircraft be self-extinguishing when tested vertically (i.e., exposed to flame while located in a vertical orientation). The average burn length is not to exceed <NUM> inches (<NUM>) and the average flame time after removal of the flame source is not to exceed <NUM> seconds. Drippings from the test specimen are not to continue to flame for more than an average of <NUM> seconds after falling.

Referring now to <FIG>, a panel assembly <NUM>, such as for use as a panel assembly <NUM> of <FIG>, may include a first veneer panel <NUM>, a second veneer panel <NUM>, and an aviation honeycomb layer <NUM> located between the first veneer panel <NUM> and the second veneer panel <NUM>. The first veneer panel <NUM> and the second veneer panel <NUM> may be bonded to the aviation honeycomb layer <NUM> using an adhesive, chemical bonding, one or more fastener, or the like. For example, the aviation honeycomb layer <NUM> may have a first surface <NUM> and a second surface <NUM>. The first veneer panel <NUM> may be coupled or attached to the first surface <NUM>, and the second veneer panel <NUM> may be coupled or attached to the second surface <NUM>. Use of the aviation honeycomb layer <NUM> may result in a relatively sturdy panel assembly <NUM> having a relatively low density. It may be desirable to reduce a mass of aircraft components (achieved using high-density materials) because greater mass of the aircraft increases fuel consumption.

The second veneer panel <NUM> may include wood, aluminum, or the like, and may be treated with a fire retardant. For example, the second veneer panel <NUM> may be formed and then submerged in a bath of a fire retardant such as a water-based fire retardant which allows the fire retardant to flow into the material of the second veneer panel <NUM>. The second veneer panel <NUM> may include one, two, or more plies of a wood material such as poplar, oak, or the like. In various embodiments, two or more plies may be oriented such that the grain of adjacent plies lie at an angle that is approximately <NUM> degrees relative to each other.

The aviation honeycomb layer <NUM> may include any aviation honeycomb material. For example, the aviation honeycomb layer <NUM> may include one or more of aluminum, fiberglass, an epoxy-based resin, a phenolic-based resin, a composite material, or the like. For example, the aviation honeycomb layer <NUM> may include columnar, hexagonal, or similar-shaped hollow cells oriented between relatively thin vertical walls.

Carbon fiber has been growing in popularity due to its relatively high tensile strength and its relatively impressive aesthetic appeal. However, it is relatively difficult to bond materials, such as metal or wood, to carbon fiber materials. While carbon fiber materials may be directly coupled to an aviation honeycomb layer, such as via use of fasteners, the resulting panel assembly has drawbacks. For example, a thickness of an entire panel assembly using a carbon fiber material as a first veneer panel may be less than a corresponding panel assembly without a carbon fiber material. In that regard, entities that manufacture aircraft furniture, such as cabinets or walls, may need to redesign features of the furniture, such as handles or knobs, to accommodate the different thickness.

Referring now to <FIG> and <FIG>, the first veneer panel <NUM> has been designed to include a face layer <NUM> that includes a carbon fiber material. The first veneer panel <NUM> may further include a backing layer <NUM> and an adhesive <NUM> used to attach the face layer <NUM> to the backing layer <NUM>. The backing layer <NUM> may be oriented adjacent to the first surface <NUM> of the aviation honeycomb layer <NUM> such that the face layer <NUM> faces away from the aviation honeycomb layer <NUM>. In that regard, the panel assembly <NUM> may be oriented in such a manner that the face layer <NUM> is exposed to be viewed by people in the environment of the panel assembly <NUM>, and the second veneer panel <NUM> may be hidden from view.

The carbon fiber material of the face layer <NUM> may be provided in sheet form and may be cut to the desired shape of the first veneer panel <NUM>. The carbon fiber material of the face layer <NUM> may include a flame-retardant carbon fiber veneer designed to resist the spread of fire. In various embodiments, the carbon fiber material may have desirable aesthetic properties such as a relatively deep luster and a relatively glossy mirror finish. For example, the carbon fiber material may include woven carbon fiber without any additives (such as a twill weave or a plain weave) or may include woven carbon fiber with fire retardant (or other) additives or fillers (such as a plastic, resin, or the like).

The backing layer <NUM> of the first veneer panel <NUM> may include any backing material such as one or more plies of wood, aluminum, or the like. For example, the backing layer <NUM> may include two plies of wood coupled together and positioned with the respective grains oriented at <NUM> degrees relative to each other.

The backing layer <NUM> may be treated with a fire retardant prior to being bonded to the adhesive <NUM>. For example, the fire retardant may include a water-based fire retardant, and the backing layer <NUM> may be submerged into a bath of the fire retardant in order to provide fire resistant properties to the backing layer <NUM>. A benefit of using a water-based fire retardant is that the water allows the fire retardant to be absorbed by the material of the backing layer <NUM>. However, in various embodiments, non-water-based fire retardant may be used in addition to, or instead of, the water-based fire retardant.

The adhesive <NUM> must include specific properties that facilitate chemical bonding to the backing layer <NUM> and the face layer <NUM>. The adhesive <NUM> is a thermoset dry film adhesive, and is a flame retardant, B-staged modified acrylic adhesive. These specific properties may allow the adhesive <NUM> to bond with the carbon fiber of the face layer <NUM> and the wood, aluminum, or other material of the backing layer <NUM>. The adhesive <NUM> may be formed or obtained in sheet form and may be cut to a desired shape of the first veneer panel <NUM>.

These properties of the adhesive <NUM> allow the adhesive <NUM> to bond with untreated carbon fiber, which is used in the face layer <NUM>. Stated differently, the carbon fiber material may be an untreated carbon fiber material, meaning that the carbon fiber material lacks chemical or other treatment via conventional methods such as water-based fire retardant. In various embodiments, the carbon fiber material may be treated by the manufacturer but not during assembly of the first veneer panel <NUM>, may be untreated by the manufacturer and during assembly of the first veneer panel <NUM>, or may be treated during assembly of the first veneer panel and not by the manufacturer.

In various embodiments, the carbon fiber material may be created to be fire retardant by the manufacturer and processes during manufacture but may lack any additional treatment after manufacture is complete. For example, materials used in aircraft veneer panels may be treated, such as with a surface layer of a vinyl material, to facilitate bonding to other materials. However, the properties of the adhesive <NUM> facilitate bonding the adhesive <NUM> to the carbon fiber of the face layer <NUM> and to the material of the backing layer <NUM> without treatment of at least one of the face layer <NUM> or the backing layer <NUM>.

Due to the fire-retardant treatment of the backing layer <NUM> (or inherent fire retardant properties of the backing layer <NUM>) and the fire retardant properties of the carbon fiber of the face layer <NUM> and the adhesive <NUM>, the first veneer panel <NUM> may satisfy the requirements set forth in Federal Aviation Regulations (FAR) Section <NUM>, as described above.

To facilitate use of the first veneer panel <NUM> in conventional aerospace environments, the first veneer panel <NUM> may have a thickness <NUM> that is similar to a thickness of conventional veneer panels. The relatively constant thickness <NUM> of the first veneer panel <NUM> may be achieved by using a face layer <NUM> and an adhesive <NUM> each having relatively small thicknesses. For example, a thickness <NUM> of the face layer <NUM> (i.e., the carbon fiber material) may be between <NUM> inches (<NUM> millimeters (mm)) and <NUM> inches (<NUM>), between <NUM> inches (<NUM>) and <NUM> inches (<NUM>), between <NUM> inches (<NUM>) and <NUM> inches (<NUM>), or about. <NUM> inches (<NUM>). Where used in this context, about refers to the referenced value plus or minus <NUM> percent of the referenced value. For example, a thickness <NUM> of the adhesive may be between <NUM> inches (<NUM> millimeters) and <NUM> inches (<NUM> millimeters), between <NUM> inches (<NUM>) and <NUM> inches (<NUM>), between <NUM> inches (<NUM>) and <NUM> inches (<NUM>), or about <NUM> inches (<NUM>).

Due to the above properties of the face layer <NUM> and the adhesive <NUM>, the face layer <NUM> and the adhesive <NUM> may be applied to any backing layer <NUM> comprising a first ply of wood. In that regard, the backing layer <NUM> may be formed to have a desired thickness, and addition of the face layer <NUM> and the adhesive <NUM> may minimally affect the thickness <NUM> of the first veneer panel <NUM>. That is, the thickness of the backing layer <NUM> may be multiple times the combined thicknesses <NUM>, <NUM> of the face layer <NUM> and the adhesive <NUM>. This may be desirable as entities that purchase the first veneer panel <NUM> may have handles, knobs, or other features that are designed for a veneer panel having a predetermined thickness. In that regard, the existing handles, knobs, or other features may be coupled to the first veneer panel <NUM> without engineering changes made to the handles, knobs, or other features. This provides the added advantage of allowing the first veneer panel <NUM> to be used in many existing aerospace environments (such as existing cabinet systems), and/or as a replacement veneer panel in existing aerospace environments.

Referring now to <FIG>, a method <NUM> for forming a panel assembly for use in aerospace applications, such as for use in cabinets or other furniture or components of an aircraft, is shown. The method <NUM> may begin at block <NUM> in which a backing layer is formed. The backing layer may be formed by cutting a single ply of a material, such as aluminum or wood, into a desired shape. In various embodiments, the backing layer may be formed by bonding or otherwise attaching two or more plies of wood or another material together. The resulting multiple ply component may then be cut into a desired shape, or the multiple plies may be cut into the desired shape before being coupled together.

In block <NUM>, the backing layer may be treated with a fire retardant. For example, the backing layer may be submerged in a bath of a water-based or other fire retardant in order to treat the backing layer, causing the backing layer to be relatively fire resistant.

In block <NUM>, a material for use as a face layer (such as a carbon fiber material) may be cut to a desired shape or size. For example, the carbon fiber material may be purchased in sheet form and may be cut to a desired shape of the panel assembly. In various embodiments, the carbon fiber material may include woven carbon fibers and may have fire retardant properties. In various embodiments, the carbon fiber material may lack fire retardant properties, and may thus be treated with a fire retardant in a similar manner as the backing layer in block <NUM>. In various embodiments, a different method of treating the carbon fiber material with the fire retardant may be employed.

In block <NUM>, an adhesive is placed between the face layer and the backing layer. For example, the adhesive may be provided in sheet form and may be cut to a desired shape to match that of the face layer and the backing layer. In various embodiments, the adhesive may be provided with thin films on either surface that reduce the likelihood of premature curing of the adhesive. In that regard, the thin films may be removed prior to stacking the adhesive between the face layer and the backing layer. Once the adhesive is in place between the face layer and the backing layer, the adhesive may be cured. The adhesive is a thermoset material and may be cured by any one or more of applying pressure to the assembly, increasing a temperature of the adhesive, or the like. Because the adhesive is a thermoset adhesive, the bonding to the face layer and the backing layer may be relatively sturdy because the adhesive may fail to reactivate after setting. After curing of the adhesive, the combination of the face layer,the adhesive, and the backing layer may be regarded as a first veneer panel.

In block <NUM>, a second veneer panel may be obtained or formed. For example, the second veneer panel may be a veneer panel which may include wood, aluminum, or other materials. In various embodiments, the second veneer panel may include identical features as the first veneer panel and may be formed in a similar manner as the first veneer panel. In various embodiments, the second veneer panel may include different features than the first veneer panel. For example, the second veneer panel may include two or more plies of wood coupled together via an adhesive or a fastener, one or more plies of aluminum, or the like, without a carbon fiber material.

In block <NUM>, the first veneer panel and the second veneer panel may be bonded or otherwise attached to a first surface and a second service, respectively, of an aviation honeycomb layer. In various embodiments, the aviation honeycomb layer may be purchased in a desired shape, may be cut to a desired shape, may be created or otherwise formed to have the desired shape, or the like. The first veneer panel and the second veneer panel may be bonded to the surfaces using an adhesive, may be attached to the surfaces using one or more fastener, or the like. The resulting assembly that includes the first veneer panel, the second veneer panel, and the honeycomb layer between the veneer panels may be regarded as a panel assembly for use in aircraft components, such as aircraft interior walls, furniture, or the like.

Benefits and other advantages have been described herein with regard to specific embodiments. However, the benefits, advantages, and any elements that may cause any benefit or advantage to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure.

Claim 1:
A panel assembly for use in an aircraft, the panel assembly comprising:
a first veneer panel (<NUM>) having:
a face layer (<NUM>) formed from a carbon fiber sheet, the carbon fiber sheet forming an exterior face of the veneer panel;
a backing layer (<NUM>) comprising a first ply of wood; and
a thermoset dry film adhesive (<NUM>) located between the face layer and the backing layer and attaching the face layer to the backing layer, wherein the thermoset dry film adhesive is a flame-retardant, B-staged modified acrylic adhesive, and
wherein the thermoset dry film adhesive directly contacts a surface of the carbon fiber sheet and a surface of the first ply of wood;
a second veneer panel (<NUM>); and
an aviation honeycomb layer (<NUM>) coupled between the first veneer panel and the backing layer of the second veneer panel.