Patent Description:
Elastomeric sheets may be used in aerospace applications. Such elastomeric sheets may be used to protect external components such as leading-edge surfaces, radomes, engine fan blades, and ice protection equipment. Conventional elastomeric processes, such as calendering, may fail to make relatively thin elastomeric sheets (e.g., less than <NUM> thousandths of an inch (<NUM> millimeters) and/or greater than <NUM> thousandths of an inch (<NUM> nanometers)). Due to this limitation, it is difficult to reduce a weight of aerospace components with conventionally-formed elastomeric sheets (any reduction in weight of an aerospace component is desirable). This limitation further reduces or eliminates the possibility of stacking multiple elastomeric sheets together such that any defect (e.g., voids, thin or thick spots, bubbles, or the like) in an elastomeric sheet is likely to affect an entire thickness of the sheet. <CIT> describes methods and apparatus for high performance structures. <CIT> describes a nose cone for a fan. <CIT> describes polyether urethane deicer boots. <CIT> describes an aircraft door arrangement. <CIT> describes a cabin door sealing structure.

Disclosed herein is a method for forming an aircraft component, as defined in claim <NUM>.

Also disclosed is an aircraft component as defined in claim <NUM>.

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.

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 <NUM> may include multiple aircraft components. For example, the aircraft <NUM> may include a nosecone <NUM>, one or more wing <NUM>, one or more door <NUM>, a fuselage <NUM>, and one or more gas turbine engine <NUM>. These and other components of the aircraft <NUM> may include, or be coupled to, additional aircraft components. For example, the nosecone <NUM> may include an erosion film <NUM> on an outer surface thereof, the wing <NUM> may have a leading edge <NUM> with a pneumatic or electrothermal deicer <NUM>, and the door <NUM> may have a seal <NUM> formed from a heated elastomer product <NUM>. Each of the erosion film <NUM>, the pneumatic or electrothermal deicer <NUM>, and the heated elastomer product <NUM> may have an inner portion which may face an interior of the component (e.g., the inner portion of the erosion film <NUM> may face the nosecone <NUM>, the inner portion of the pneumatic or electrothermal deicer <NUM> may face the wing <NUM>, and the inner portion of the heated elastomer product <NUM> may face the door <NUM> or the fuselage <NUM>). Each of the erosion film <NUM>, the pneumatic or electrothermal deicer <NUM>, and the heated elastomer product <NUM> may further include an outer layer. The outer layer may be formed from, or may include, an elastomeric material and may be formed using an extrusion process. In various embodiments, the outer layer may face an environment of the aircraft component. For example, the outer portion of the erosion film may face oncoming air, the outer portion of the electrothermal deicer <NUM> may face oncoming air, and the outer portion of the heated elastomer product <NUM> may face air in response to the door <NUM> being opened.

Using extrusion to form an elastomeric outer layer may provide several benefits and advantages over forming an elastomeric outer layer using a conventional method. For example, the use of extrusion allows the outer layer to be relatively thin, thus reducing weight of the aircraft component. Because extrusion allows for the formation of thinner layers, multiple layers may be stacked together to form a desired thickness of the total outer layer. The ability to stack multiple layers together provides benefits such as reducing the likelihood of defects (e.g., cracks, pores, or the like) extending through the outer layer, and simultaneously increasing the likelihood of uniformity of thickness of the outer layer. Thus, the use of extrusion results in a more robust product with an extended operating life and potentially having a lower weight, all desirable characteristics for aircraft components.

Turning to <FIG>, a method <NUM> for forming an aircraft component having an elastomeric surface or erosion ply is shown. The method <NUM> begins in block <NUM> where an inner portion of the aircraft component is formed. The inner portion of the aircraft component may be formed using any method such as casting, forging, or the like. The inner portion may be formed to have any desirable shape including straight lines, angles, curves, or the like on at least one of edges or surfaces. The inner portion may include at least one of an adhesive, an elastomer, a rubber, a neoprene, a metal, or a woven fabric.

In block <NUM>, one or more outer layer may be formed using an extrusion process. The outer layer includes an elastomeric material and includes multiple plies (i.e., multiple outer layers) coupled together. Each of the multiple plies is formed using the extrusion process. The extrusion process may include any type of extrusion such as blown extrusion or cast extrusion. The outer layer may be formed to have a shape that corresponds to a shape of an outer surface of the inner portion. The outer layer is formed via extrusion into a sheet structure and cut to a desired shape.

Blown extrusion, which may be referred to as blown film extrusion, is a process of extrusion of molten materials and constant inflation of the material to several times its initial diameter. This may result in a thin, tubular product which may be slit to create a flat film. The extrusion may be done via an annular slit die, generally vertically, for the formation of a thin-walled tube. The introduction of air takes place through a hole present in the die's center for blowing up the tube just like a balloon. The cooling of the hot film is done by the high-speed air ring that blows onto it. This air ring is mounted on the top of die.

Cast extrusion includes a molten polymer that travels through a flat die system to adopt its final flat film shape. The die system is formed by the die and feedblock (if the process requires coextrusion) or simply the die, if the process is that of mono-layer extrusion. The process starts with the feeding of plastic resins by means of a gravimetric feeding system to one or more extruders. The materials are then melted and mixed by the extruders, filtered and fed to the die system. Immediately after exiting the die, the molten curtain enters the cooling unit where its temperature is lowered with a water-cooled chill roll to "freeze" the film. The film is then passed downstream where the edges are trimmed, corona treatment is applied (if a fabrication process such as printing or coating is required) and the film is wound into rolls.

In block <NUM>, the outer layers are coupled to the inner portion. The outer layer are coupled to the inner portion using adhesive and fasteners.

Referring to <FIG>, which shows an example not within the scope of the claims, an aircraft component <NUM> may include an inner portion <NUM> and an outer layer <NUM>. An adhesive <NUM> may be applied between the inner portion <NUM> and the outer layer <NUM> and used to couple the outer layer <NUM> to the inner portion <NUM>. In that regard, the adhesive <NUM> resists separation of the outer layer <NUM> from the inner portion <NUM>. The adhesive may be heat-cured, chemically-cured, moisture-cured, anaerobic-cured, or the like.

The outer layer <NUM> may be formed using an extrusion process. In that regard, the outer layer <NUM> may be formed to have a relatively small thickness <NUM>. For example, the total thickness of the outer layer <NUM> may be between (<NUM> thousandths of an inch and <NUM> thousandths of an inch) <NUM> millimeters (mm) and <NUM>, between (<NUM> thousandths of an inch and <NUM> thousandths of an inch) <NUM> and <NUM>, or between (<NUM> thousandths of an inch and <NUM> thousandths of an inch) <NUM> and <NUM>.

The outer layer <NUM> may include a single ply. The material of the outer layer <NUM> may include any elastomeric material. For example, the outer layer <NUM> may include a natural rubber, a synthetic rubber, a silicone, an elastomer, a thermoplastic, a thermoset, a polymeric material, or the like.

Use of the extrusion process results in the outer layer <NUM> being resistant to a relatively wide range of temperatures. Stated differently, use of the extrusion process results in the outer layer <NUM> retaining its physical properties in response to being exposed to a relatively wide range of temperatures. For example, the outer layer <NUM> may be capable of retaining its physical properties in response to being exposed to temperatures between (negative one hundred (-<NUM>) degrees Fahrenheit (F) and <NUM> degrees F) -<NUM> degrees Celsius (C) and <NUM> degrees C, between (-<NUM> degrees F and <NUM> degrees F) -<NUM> degrees C and <NUM> degrees C, or between -(<NUM> degrees F and <NUM> degrees F) -<NUM> degrees C and <NUM> degrees C.

Turning to <FIG>, another aircraft component <NUM> is include an inner portion <NUM>, an outer layer <NUM>, and one or more fasteners <NUM>. Whereas the outer layer <NUM> of <FIG> includes a single ply, the outer layer <NUM> of <FIG> includes multiple plies, or multiple outer layers. In particular, the outer layer <NUM> includes a first outer layer <NUM>, a second outer layer <NUM>, and a third outer layer <NUM> stacked on top of each other. The fastener <NUM> extends through each of the outer layers <NUM>, <NUM>, <NUM> and a portion of the inner portion <NUM> and to fasten each of the outer layers <NUM>, <NUM>, <NUM> the inner portion <NUM> together. An adhesive is used in addition to the fastener <NUM> to couple each of the outer layers <NUM>, <NUM>, <NUM> together.

Each of the outer layers <NUM>, <NUM>, <NUM> is formed using an extrusion process, and may have the same or different thicknesses. Each of the outer layers <NUM>, <NUM>, <NUM> may be formed at the same time using the extrusion process. A single sheet of outer layer is formed and cut into each of the outer layers <NUM>, <NUM>, <NUM>. In various embodiments, each of the outer layers <NUM>, <NUM>, <NUM> may be formed as separate parts. In various embodiments, each of the outer layers <NUM>, <NUM>, <NUM> may be formed from the same materials. For example, each of the outer layers <NUM>, <NUM>, <NUM> may include a natural rubber. Each of the outer layers <NUM>, <NUM> may include any one or more of a natural rubber, a synthetic rubber, a silicone, an elastomer, a thermoplastic, a thermoset, a polymeric material, or the like.

Use of the extrusion process allows each of the outer layers <NUM>, <NUM>, <NUM> to have a relatively small thickness. For example, a thickness <NUM> of the each of the outer layers <NUM>, <NUM>, <NUM> may be between <NUM> thousandths of an inch and <NUM> thousandths of an inch (<NUM> millimeters (mm) and <NUM>), between <NUM> thousandths of an inch and <NUM> thousandths of an inch (<NUM> and <NUM>), or between <NUM> thousandths of an inch and <NUM> thousandths of an inch (<NUM> and <NUM>). Additional outer layers may be added in order to achieve a desired thickness of the combined outer layer <NUM>. Because of the separate outer layers <NUM>, <NUM>, <NUM>, a defect in one of the outer layers (e.g., <NUM>) is limited to that layer, and thus the defect is unlikely to extend through the entire outer layer (including the combination of outer layers <NUM>, <NUM>, <NUM>).

Benefits and other advantages have been described herein with regard to specific embodiments.

A method and apparatus are provided herein. In the detailed description herein, references to "various embodiments", "one embodiment", "an embodiment", "an example embodiment", etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic.

Claim 1:
A method for forming an aircraft component, the method comprising:
forming (<NUM>) an inner portion (<NUM>) of the aircraft component (<NUM>);
forming (<NUM>) a combined outer layer (<NUM>) of the aircraft component (<NUM>) using extrusion of an elastomeric material; and wherein forming (<NUM>) the combined outer layer (<NUM>) of the aircraft component (<NUM>) further comprises:
extruding a single sheet of elastomeric material;
cutting the single sheet of elastomeric material into multiple outer layers (<NUM>,<NUM>,<NUM>);
stacking the multiple outer layers (<NUM>,<NUM>,<NUM>) together; forming a desired thickness of the combined outer layer (<NUM>) by repeating the extruding, cutting, and stacking steps; and
coupling (<NUM>) the multiple outer layers (<NUM>,<NUM>,<NUM>) of the aircraft component to the inner portion (<NUM>) of the aircraft component by a fastener, wherein the fastener (<NUM>) extends through each of the multiple outer layers (<NUM>,<NUM>,<NUM>) and a portion of the inner portion (<NUM>), wherein coupling the multiple outer layers (<NUM>,<NUM>,<NUM>) of the aircraft component to the inner portion of the aircraft component includes applying an adhesive between each of the multiple outer layers (<NUM>,<NUM>,<NUM>) to form the combined outer layer (<NUM>),
and includes applying the adhesive between the combined outer layer (<NUM>) and the inner portion (<NUM>).