Multi-component melting electromagnetic effect shielding cap system

Abstract

The present invention relates to a multi-component fused electromagnetic effect protective cap system, a protective cap assembly for enclosing the end of a fastener extending through an aircraft structure, the protective cap assembly comprising a cap member having a sidewall, the sidewall defining an opening and an interior space, wherein the opening is aligned with the interior space for receiving the fastener end through the opening and into the interior space, the sidewall further defining an end face that abuts the structure, and a protrusion secured to the end face of the sidewall of the cap member and extending from the end face.

Description

Technical Field

[0001] The present invention relates to an electromagnetic effect ("EME") protective cap, and more particularly to an EME protective cap that closes the end of a fastener by securing the protective cap to a structure extending from the end of the fastener. Background Art

[0002] An EME protective cap is installed to enclose the end of a fastener extending from a structure. The enclosed end of the fastener isolates the end of the fastener from the environment into which the end of the fastener would otherwise extend as it extends from the structure. Depending on the location of the structure, the environment into which the end of the fastener may extend may include volatile vapors, volatile liquids, or sensitive equipment. Securing the protective cap over the end of the fastener and enclosing the end of the fastener with the protective cap secured to the structure helps prevent sparks from emanating from the end of the fastener and interacting with the environment into which the end of the fastener would otherwise extend in the event of a lightning strike or other electromagnetic event. Enclosing the end of the fastener prevents sparks from interacting with volatile vapors, liquids, or sensitive equipment located in the area of the end of the fastener extending from the structure.

[0003] Protective caps are constructed from a variety of materials, such as thermosets, thermoplastics, epoxies, or other common materials used in protective cap construction. Installation of the protective cap involves the use of a sealant that adheres the protective cap to the structure and seals the protective cap to the structure around the ends of the fasteners, thereby isolating the ends of the fasteners from the environment outside the protective cap. The use of sealants is time consuming and can result in faulty installation of the protective cap, requiring the cap to be reinstalled. Faulty installation of the protective cap can occur when the sealant is used due to the sealant decompressing the sealant, causing the protective cap to lift from the structure. Other faulty installations can occur due to the force of gravity exerted on the protective cap, causing the protective cap to move before it is fully seated in place on the structure.

[0004] Defective installations require reinstallation, resulting in increased costs during the original manufacture of a manufactured structure (e.g., an aircraft) or during maintenance of the structure. Curing of the sealant consumes time, both during the original manufacture and during maintenance involving the sealant. Furthermore, additional labor and costs are required for maintenance of the structure. For example, an aircraft requiring replacement of a protective cap requires cleaning of residual sealant before the replacement cap can be installed. Therefore, it would be beneficial to be able to secure the protective cap to the structure and seal the end of the fastener without using a sealant to secure the cap to the structure.

[0005] For example, since structures such as aircraft often contain numerous protective caps, improvements in installation time and improved installation quality rates can provide value when installing protective caps during aircraft manufacturing. If the caps can be installed without the time spent manually applying sealant and allowing it to cure, the time improvements associated with installing the caps will be further enhanced. Similarly, improved installation time and improved installation quality rates can provide value when replacing protective caps during maintenance on aircraft and other structures.

[0006] When installing a protective cap, such as one configured to secure the cap to a thermoplastic structure using a polysulfide sealant, such as within an aircraft fuel tank, an adhesion promoter may be required to achieve the necessary adhesion. Adhesion promoters can be potentially hazardous chemicals. Therefore, it would be beneficial to position and secure the cap in the desired position on the structure without the use of sealants or adhesion promoters.

[0007] The features, functions, and advantages that have been discussed can be achieved independently in various embodiments or may be combined in yet other embodiments further details of which can be seen with reference to the following description and drawings. Summary of the Invention

[0008] One embodiment of the present invention includes a protective cap assembly for enclosing an end of a fastener extending through an aircraft structure, the aircraft structure including a cap member having a sidewall. The sidewall defines an opening and an interior space, wherein the opening is aligned with the interior space for receiving the end of the fastener through the opening and into the interior space, and the sidewall further defines an end surface for abutting the structure. The protective cap assembly also includes a protruding member secured to and extending from the end surface of the sidewall of the cap member.

[0009] One example includes a protective cap system for enclosing an end of a fastener extending through a structure of an aircraft, the structure comprising a cap member having a sidewall. The sidewall defines an opening and an interior space, wherein the opening is aligned with the interior space for receiving the end of the fastener through the opening and into the interior space, and the sidewall further defines an end face for abutting the structure. The protective cap system also includes a protruding member separate from the cap member, wherein the protruding member is constructed of a thermoplastic material and is positioned within the opening defined in the structure, and the end face is positioned in covering relation with the protruding member.

[0010] One example includes a method for installing a protective cap assembly for enclosing an end of a fastener extending through a structure of an aircraft, the method comprising the steps of positioning the protective cap assembly onto the structure enclosing the end of the fastener, wherein the protective cap assembly includes a cap member having a sidewall, the sidewall defining an opening and an interior space, wherein the opening is aligned with the interior space for receiving the end of the fastener through the opening and entering the interior space by positioning the protective cap assembly, and the sidewall further defines an end face that abuts the structure by positioning the protective cap assembly. The protective cap assembly includes a protruding member constructed of a thermoplastic material, the protruding member being secured to and extending from the end face of the cap member such that the protruding member enters the opening defined by the structure by positioning the protective cap assembly. The method further comprises applying one of heat or ultrasound to the thermoplastic material of the protruding member, thereby melting the thermoplastic material. The method further comprises cooling the thermoplastic material of the protruding member, causing the thermoplastic material of the protruding member to harden and adhere to the cap member and the structure, thereby securing the cap member to the structure.

[0011] One example includes a method for installing a protective cap system for enclosing an end of a fastener extending through a structure of an aircraft, the method comprising the steps of positioning a protruding member of the protective cap system comprised of a thermoplastic material into an opening defined in the structure. The method comprises the steps of positioning a cap member of the protective cap system on the structure, the cap member being separate from the protruding member, wherein the cap member has a sidewall defining an opening and an interior space, wherein the opening is aligned with the interior space such that positioning the cap member on the structure causes the end of the fastener to extend through the opening and into the interior space. The sidewall defines an end face adjacent to the structure such that positioning the cap member on the structure causes the end face to overlie the protruding member. The method further comprises the steps of applying one of heat or ultrasound to the thermoplastic material of the protruding member to melt the thermoplastic material, and cooling the thermoplastic material of the protruding member such that the thermoplastic material of the protruding member hardens and adheres to the end face of the cap member and the structure, thereby securing the cap member to the structure.

[0012] One example includes a method for installing a protective cap for enclosing an end of a fastener extending through a structure of an aircraft, the method comprising the steps of positioning the protective cap on the structure, wherein the protective cap has a sidewall defining an opening and an interior space, wherein the opening is aligned with the interior space such that positioning the protective cap on the structure causes the end of the fastener to extend through the opening and into the interior space, and wherein an end of the sidewall of the cap member is comprised of a thermoplastic material, the end including an end face that abuts the structure upon positioning the protective cap on the structure. The method further comprises the steps of applying one of heat or ultrasound to the end of the sidewall of the cap member to melt the thermoplastic material of the end, and cooling the end of the sidewall of the cap member to cause the thermoplastic material of the end of the sidewall to harden and adhere to the structure and the remainder of the sidewall of the cap member, thereby securing the cap member to the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is an exploded perspective view of a first example of a protective cap assembly in an inclined position relative to installed alignment of the protective cap assembly with an end of a fastener extending through a structure;

[0014] Figure 2 The first example of a protective cap assembly is along Figure 1 A cross-sectional view taken along line 2-2 of the figure, wherein the protective cap assembly is positioned on a structure and encloses an end of a fastener extending through the structure;

[0015] Figure 3 is an exploded perspective view of a second example of a protective cap assembly in an inclined position relative to installed alignment of the protective cap assembly with an end of a fastener extending through a structure;

[0016] Figure 4 A second example of a protective cap assembly is provided along Figure 3 A cross-sectional view taken along line 4-4 of the embodiment of the present invention, wherein the protective cap assembly is positioned on a structure and encloses an end of a fastener extending through the structure;

[0017] Figure 5 is an exploded perspective view of a first example of a protective cap system with the protective cap in an inclined position relative to installed alignment of the protective cap assembly with an end of a fastener extending through a structure;

[0018] Figure 6 is the first example of a protective cap system along Figure 5 A cross-sectional view taken along line 6-6 of the embodiment of the present invention, wherein the protective cap system is positioned on the structure and encloses the end of the fastener extending through the structure;

[0019] Figure 7is an exploded perspective view of a second example of a protective cap system, the protective cap being in an inclined position relative to installed alignment of the protective cap assembly with an end of a fastener extending through a structure;

[0020] Figure 8 A second example of a protective cap system is provided along Figure 7 A cross-sectional view taken along line 8-8 of the embodiment of the present invention, wherein the protective cap system is positioned on a structure and encloses an end of a fastener extending through the structure;

[0021] Figure 9 is a flow chart of a method for installing a protective cap assembly for enclosing an end of a fastener extending through a structure;

[0022] Figure 10 is a flow chart of a method for installing a protective cap system for enclosing an end of a fastener extending through a structure;

[0023] Figure 11 is a flow chart of a method for installing a protective cap for closing an end of a fastener extending through a structure;

[0024] Figure 12 is an exploded perspective view of the protective cap in an inclined position relative to its installed alignment with the end of a fastener extending through a structure; and

[0025] Figure 13 Is a protective hat brim Figure 12 13 - 13 , the protective cap is positioned on the structure and encloses the end of the fastener extending through the structure. DETAILED DESCRIPTION

[0026] refer to Figure 1-4 , shows a first example of a protective cap assembly 10 and a second example of a protective cap assembly 10 ′ for enclosing an end 12 of a fastener 14 extending through a structure 16 of an aircraft in this example. The first example of the protective cap assembly 10 is shown in FIG. Figure 1 and Figure 2 , and includes a cap member 18 having a sidewall 20 defining an opening 22 and an interior space 24, wherein the opening 22 is aligned with the interior space 24 for receiving the end 12 of the fastener 14 through the opening 22 and into the interior space 24. The sidewall 20 further defines an end face 26 for the abutment structure 16. The protective cap assembly 10 also includes a protruding member 28 secured to and extending from the end face 26 of the sidewall 20 of the cap member 18.

[0027] The cap member 18 is made of one or more materials, including thermosetting materials, thermoplastic materials, epoxy resins and other materials used for cap member construction, which are used to close the ends of the fasteners to provide protection against EME events. The cap member 18 can also be constructed by one of various methods, such as using injection molding technology, three-dimensional printing technology and other manufacturing technologies. Regarding the first example of the protective cap assembly 10, the construction of the protruding member 28 will be a construction of a thermoplastic material. The thermoplastic material selected for constructing the protruding member 28 will desirably have a melting temperature lower than the melting temperature of the material used to construct the cap member 18. Compared to the melting temperature of the material constructing the cap member 18, the melting temperature of the thermoplastic material constructing the protruding member 28 is lower, so that the protruding member 28 is selectively melted without melting the cap member 18. By selectively melting the thermoplastic material of the protruding member 28 in contact with the cap member 18 and the structure 16, subsequent cooling of the molten thermoplastic material causes the thermoplastic material to harden and adhere to the cap member 18 and the structure 16, thereby securing the cap member 18 to the structure 16 without melting the cap member 18 during the securing process.

[0028] The end face 26 of the sidewall 20 has a width dimension W that extends from an inner edge 30 of the sidewall 20 defining the opening 22 to an outer edge 32 of the sidewall 20. In the present example, the protruding member 28 is located between the inner edge 30 and the outer edge 32 of the end face 26. In the present example, the protruding member 28 extends in a direction D that is transverse to the end face 26. The protruding member 28 includes a wall member 34 having an inner wall surface 36 that is a first radial distance 38 from a central axis 40 of the cap member 18 and an outer wall surface 42 that is a second radial distance 44 from the central axis 40, wherein the second radial distance 44 is greater than the first radial distance 38.

[0029] like Figure 1 As shown, the wall member 34 extends annularly about the central axis 40 of the cap member 18. Figure 1As shown, a width dimension W1 of the wall member 34 between the inner wall surface 36 and the outer wall surface 42 is a predetermined dimension for forming an interference fit with the wall member 34 positioned within an opening 46 defined in the structure 16. In this example, both the wall member 34 and the opening 46 have an annular configuration. In this example, the opening 46 is located within a channel 47, which is positioned to extend around the end 12 of the fastener 14 and is configured to have a dimension that creates friction between the wall member 34 and the sidewalls 48 of the opening 46 or channel 47. The wall member 34 is inserted into the opening 46 to form an interference fit with the sidewalls 48 of the opening 46 or channel 47. The interference fit of the wall member 34 with the sidewalls 48 of the opening 46 or channel 47 facilitates the installer in positioning the cap member 18 relative to the structure 16 and holds the cap member 18 in place regardless of its orientation, allowing the installer to further secure the cap member 18 to the structure 16 by melting the protruding member 28, as will be described further below. Melting of the protruding member 28 and the melt-fastening process can be accomplished without requiring an installer to secure the cap member 18 to the structure 16 .

[0030] The cap member 18 is held in the desired position, and the interference fit between the wall member 34 and the sidewall 48 of the opening 46 relative to the structure 16 further secures the cap member 18 to the structure 16, regardless of the orientation of the cap member 18. Such orientations may include, for example, the structure 16 being positioned on top and the cap member 18 being placed in an upside-down position, the structure 16 being positioned so as to extend vertically and the cap member being positioned so as to extend outward from the structure 16, or the structure 16 being positioned on an inclined plane relative to horizontal. With the cap member 18 positioned in any of these different orientations, gravity is prevented from moving the cap member 18 from the desired position by the interference fit between the wall member 34 and the sidewall 48 of the opening 46, or in this example, the sidewall 48 of the channel 47. The interference fit holds the cap member 18 in the desired position for subsequent securing of the cap member 18 to the structure 16 by melting and thereafter cooling the thermoplastic material of the protruding member 28. As the thermoplastic material of the protruding member 28 cools, the thermoplastic material adheres to the structure 16 and the cap member 18, and as the thermoplastic material hardens, the hardened thermoplastic material secures the cap member 18 to the structure 16. The interference fit of the wall member 34 with the sidewalls 48 of the opening 46, or in this example, the sidewalls 48 of the channel 47, facilitates easier installation of the protective cap assembly 10 and relieves the installer of any inconvenience of having to hold the cap member 18 in place while further securing the cap member 18 to the structure 16 is performed.

[0031] A second example of a protective cap assembly 10' is shown in FIG. Figure 3 and Figure 4In the second example, the protruding member 28 includes a post member 50 positioned to extend from the end face 26 of the sidewall 20. In this example, a plurality of post members 50 are positioned to be spaced apart from one another about the central axis 40 of the cap member 18. The post members 50 define a predetermined diameter D1 and form a circumferential surface 51 around the post members 50 that forms an interference fit with the sidewall 52 of the opening 46, or in this example, with the hole 54 defined in the structure 16, and positions the post members 50 within the hole 54.

[0032] In this example, a plurality of strut members 50 are each positioned within a corresponding aperture 54 defined in the structure 16. By creating an interference fit between the circumferential surfaces 51 of the strut members 50 and the sidewalls 52 of the apertures 54, the cap member 18 is retained in a desired position relative to the structure 16, and as previously described, any inconvenience of the installer having to hold the cap member 18 in place regardless of its orientation in order to further secure the cap member 18 to the structure 16 is eliminated. Further securing of the cap member 18 includes the installer melting the thermoplastic material of which the strut members 50 are constructed. Subsequent cooling of the thermoplastic material in contact with the structure 16 and the cap member 18 causes the thermoplastic material to adhere to the structure and the cap member 18, and hardening of the thermoplastic material secures the cap member 18 to the structure 16.

[0033] As discussed above, the thermoplastic material selected for constructing the protruding member 28 (e.g., the post member 50 of the present example) will desirably have a melting temperature lower than the melting temperature of the material comprising the cap member 18. The lower melting temperature of the thermoplastic material of the post member 50 than the melting temperature of the material constructing the cap member 18 provides for selective melting of the post member 50 for securing the cap member 18 to the structure 16 without melting the cap member 18 during the securing process.

[0034] refer to Figure 5-Figure 8 , shows a first example of a protective cap system 56 and a second example of a protective cap system 56 ′ for enclosing the end 12 of a fastener 14 extending through a structure 16 (in this example, the structure 16 of an aircraft). The first example of the protective cap system 56 is shown in FIG. Figure 5 and Figure 61 and includes a cap member 18 having a sidewall 20 defining an opening 22 and an interior space 24, wherein the opening 22 is aligned with the interior space 24 for receiving the end 12 of the fastener 14 through the opening 22 and into the interior space 24. The sidewall 20 further defines an end face 26 for abutting the structure 16. The protective cap system 56 also includes a protruding member 58 separate from the cap member 18, wherein the protruding member 58 is constructed of a thermoplastic material. By positioning the protruding member 58 within the opening 46 defined in the structure 16, the end face 26 is positioned in an overlapping relationship with the protruding member 58 and the structure 16.

[0035] Reference Figure 5 and Figure 6 The protruding member 58 includes a wall member 60 configured in an annular configuration and having a predetermined wall thickness dimension T. The wall member 60 forms an interference fit by being positioned within the opening 46 defined in the structure 16 and contacting the wall member 60 with the sidewall 48 of the opening 46 or passage 47, which in this example is the passage 47. The opening 46 or passage 47 and the wall member 60 each have an annular configuration. The wall member 60 has a diameter D2 such that the end surface 26 of the side wall 20, which is located on the structure 16, overlies the wall member 60.

[0036] In a first example of using the protective cap system 56, an installer inserts the wall member 60 into the opening 46 (or in this example, the channel 47), wherein an interference fit between the wall member 60 and the sidewalls 48 of the opening 46 or channel 47 holds the wall member 60 in place within the opening 46 or channel 47. Figure 6 As shown, the end face 26 of the side wall 20 of the cap member 18 is positioned to cover the structure 16 and the wall member 60, wherein the wall member 60 is located in the opening 46 or the channel 47. With the cap member 18 in place covering the wall member 60, the thermoplastic material of the wall member 60 is melted using heat or ultrasound. The melted thermoplastic material of the wall member 60 in contact with the structure 16 and the end face 26 of the side wall 20 of the cap member 18 subsequently cools and hardens, thereby adhering to the structure 16 and the end face 26, thereby fixing the cap member 18 and the structure 16 together. As previously described, by selecting a thermoplastic material for the wall member 60 that has a melting temperature lower than the melting temperature of the material constituting the cap member 18, the thermoplastic material of the wall member 60 that has been melted to achieve fixation of the cap member 18 and the structure 16 can be obtained without causing the material of the cap member 18 to melt.

[0037] refer to Figure 7 and Figure 8, a second example of a protective cap system 56' is shown, which includes a cap member 18 having a sidewall 20 defining an opening 22 and an interior space 24, wherein the opening 22 is aligned with the interior space 24 for receiving the end 12 of the fastener 14 through the opening 22 and into the interior space 24. The sidewall 20 further defines an end face 26 that abuts the structure 16. The protective cap system 56' also includes a protruding member 58' separate from the cap member 18, wherein the protruding member 58' is constructed of a thermoplastic material. The end face 26 is positioned in an overlapping relationship with the protruding member 58' and the structure 16 by the protruding member 58' being positioned within the opening 46 defined in the structure 16.

[0038] Reference Figure 7 and Figure 8 , the protruding member 58' includes a strut member 62 defining a predetermined diameter D3, and the strut member 62 forms a circumferential surface 64 around the strut member 62, the circumferential surface 64 forming an interference fit with a sidewall 66 of the opening 46, the opening 46 including a hole 68 defined in the structure 16, wherein the strut member 62 is positioned in the hole 68. In this example, a plurality of strut members 62 are used and positioned within the plurality of holes 68. The plurality of holes 68 are defined by the structure 16 and are positioned spaced apart from each other so that the cap member 18 covers the plurality of strut members 62 and the cap member 18 is positioned on the structure 16.

[0039] like Figure 7 and Figure 8 As shown, a second example of a protective cap assembly 56' is used, wherein the installer inserts the strut members 62 into the holes 68 so that, in this example, the strut members 62 are positioned in each hole 68. Each strut member 62 has an interference fit with the corresponding hole 68 into which the strut member 62 is inserted. The interference fit holds the strut member 62 in place within each hole 68. Figure 7 and Figure 8 As shown, the end surface 26 of the side wall 20 of the cap member 18 is positioned to cover the structure 16 and the support member 62. By positioning the cap member 18 to cover the support member 62, the thermoplastic material of the support member 62 is melted using heat or ultrasound. The melted thermoplastic material of the support member 62 contacts the structure 16 and the end surface 26 of the side wall 20 of the cap member 18, and then cools and hardens, thereby adhering to the structure 16 and the end surface 26, thereby fixing the cap member 18 and the structure 16 together. As previously mentioned, it is desirable to select a thermoplastic material for the support member 62 that has a melting temperature lower than the melting temperature of the material constituting the cap member 18. The thermoplastic material of the support member 62 is melted to achieve the fixing of the cap member 18 and the structure 16 together without causing the material of the cap member 18 to melt.

[0040] refer to Figure 9A method 70 for installing a protective cap assembly 10, 10' for enclosing an end 12 of a fastener 14 extending through a structure 16 of an aircraft comprises a step 72, such as Figure 1-4 1 , wherein the protective cap assembly 10, 10' is positioned on a structure 16 enclosing the end 12 of the fastener 14. The protective cap assembly 10, 10' includes a cap member 18 having a side wall 20 defining an opening 22 and an interior space 24, wherein the opening 22 is aligned with the interior space 24 to receive the end 12 of the fastener 14 through the opening 22 and into the interior space 24 by positioning the protective cap assembly 10, 10'. The end face 26 is positioned adjacent to the structure 16 by positioning the protective cap assembly 10, 10', and the cap member 18 includes a protruding member 28 constructed of a thermoplastic material, which is fixed to and extends from the end face 26 of the cap member 18 so that the protruding member 28 enters the opening 46 defined by the structure 16 by positioning the protective cap assembly 10, 10'. The method 70 also includes a step 74 of applying one of heat or ultrasound to the thermoplastic material of the protruding member 28 to melt the thermoplastic material, and a step 76 of cooling the thermoplastic material of the protruding member 28 so that the thermoplastic material of the protruding member 28 hardens and adheres to the cap member 18 and the structure 16, thereby securing the cap member 18 to the structure 16.

[0041] Reference Figure 10 A method 78 for installing a protective cap system 56, 56' that encloses an end 12 of a fastener 14 extending through a structure 16 of an aircraft includes a step 80 of positioning a protruding member 58, 58' of the protective cap system 56, 56', each constructed of a thermoplastic material, into an opening 46 defined in the structure 16. The method 78 also includes a step 82 of positioning a cap member 18 of the protective cap system 56, 56', separated from the protruding member 58, 58', onto the structure 16, wherein the cap member 18 has a sidewall 20. The sidewall 20 defines an opening 22 and an interior space 24, wherein the opening 22 is aligned with the interior space 24 such that positioning the cap member 18 onto the structure 16 causes the end 12 of the fastener 14 to extend through the opening 22 and into the interior space 24. The sidewall 20 defines an end face 26 that abuts the structure 16 such that positioning the cap member 18 causes the end face 26 to cover the protruding member 58, 58'. With the cap member 18 positioned, a step 84 of applying one of heat or ultrasound to the thermoplastic material of the protruding members 58, 58' is employed to melt the thermoplastic material. The method 78 further includes a step 86 of cooling the thermoplastic material of the protruding members 58, 58' such that the thermoplastic material of the protruding members 58, 58' hardens and adheres to the end face 26 of the cap member 18 and the structure 16, thereby securing the cap member 18 to the structure 16.

[0042] refer to Figure 11, shows a method 88 for installing a protective cap 19 enclosing an end 12 of a fastener 14 extending through a structure 16 of an aircraft, and in Figure 12 and Figure 13 . The method 88 includes a step 90 of positioning the protective cap 19 on the structure 16, wherein the protective cap 19 has a sidewall 20 defining an opening 22 and an interior space 24, wherein the opening 22 is aligned with the interior space 24 so that the end of the fastener extends through the opening 22 and into the interior space 24 by positioning the protective cap 19 on the structure. The sidewall 20 also defines an end 96 of the sidewall 20 of the protective cap 19, which is constructed of a thermoplastic material and includes a step 92 of applying one of heat or ultrasound to the end 96 of the sidewall 20 of the protective cap 19 and melting the thermoplastic material of the end 96. Method 88 also includes step 94 of cooling end 96 of sidewall 20 of protective cap 19 so that the thermoplastic material of end 96 of sidewall 20 hardens and adheres to structure 16 and remaining portion 98 of sidewall 20 of protective cap 19 , thereby securing protective cap 19 to structure 16 .

[0043] If the protective cap 19 is positioned in an orientation relative to the structure 16 such that gravity can displace the protective cap 19 from its desired position on the structure 16, an adhesive can be applied between the protective cap 19 and the structure 16 to temporarily secure the protective cap 19 to the structure 16 before melting the end 96 of the protective cap 19 and more securely securing the protective cap 19 to the structure 16. With the protective cap temporarily secured to the structure 16, the installer can continue to melt the end 96 so that hardening of the end 96 further secures the protective cap 19 to the structure 16. Similarly, as previously described, the adhesive used to temporarily secure the cap member 18 can be applied as needed to temporarily secure the cap member 18 to the structure 16. As previously described, this approach can be employed before melting and hardening the thermoplastic material of the protruding member, such as 28, 58, or 58', to more securely secure the cap member 18 to the structure 16.

[0044] Furthermore, the present disclosure includes embodiments according to the following clauses:

[0045] Clause 1. A protective cap assembly (10, 10') for enclosing an end (12) of a fastener (14) extending through a structure (16) of an aircraft, the protective cap assembly comprising:

[0046] A cap member (18) having a sidewall (20) defining:

[0047] an opening (22) and an interior space (24), wherein the opening (22) is aligned with the interior space (24) to receive an end (12) of a fastener (14) through the opening (22) and into the interior space (24); and

[0048] an end surface (26) adjacent to the structure (16); and

[0049] A protruding member (28) is secured to and extends from an end surface (26) of the side wall (20) of the cap member (18).

[0050] Clause 2. The protective cap assembly (10) of clause 1, wherein the width dimension (W) of the end surface (26) of the side wall (20) extends from an inner edge (30) of the side wall (20) to an outer edge (32) of the side wall (20), the inner edge defining the opening (22).

[0051] Clause 3. The protective cap assembly (10) of Clause 2, wherein the protruding member (28) is located between the inner edge (30) and the outer edge (32) of the end surface (26).

[0052] Clause 4. The protective cap assembly (10, 10') according to any one of clauses 1 to 3, wherein the protruding member (28) extends in a direction (D) transverse to the end face (26).

[0053] Clause 5. A protective cap assembly (10) according to any one of clauses 1-4, wherein the protruding member (28) includes a wall member (34) having an inner wall surface (36) and an outer wall surface (42), the inner wall surface (36) being at a first radial distance (38) from a central axis (40) of the cap member (18), and the outer wall surface (42) being at a second radial distance (44) from the central axis (40), wherein the second radial distance (44) is greater than the first radial distance (38).

[0054] Clause 6. The protective cap assembly (10) of Clause 5, wherein the wall member (34) extends annularly about the central axis (40) of the cap member (18).

[0055] Clause 7. A protective cap assembly (10) according to clause 5 or 6, wherein a width dimension (W1) of the wall member (34) between the inner wall surface (36) and the outer wall surface (42) is a predetermined dimension to create an interference fit by positioning the wall member (34) in an opening (46) defined in the structure (16).

[0056] Clause 8. The protective cap assembly (10') of any one of clauses 1-4, wherein the protruding member (28) comprises a post member (50) positioned to extend from an end surface (26) of the side wall (20).

[0057] Clause 9. The protective cap assembly (10') according to Clause 8, further comprising a plurality of support members (50) spaced apart from each other.

[0058] Clause 10. The protective cap assembly (10') of Clause 9, wherein a plurality of support members (50) are spaced apart from one another and positioned about a central axis (40) of the cap member (18).

[0059] Clause 11. A protective cap assembly (10') according to clause 8, wherein the support member (50) defines a predetermined diameter (D1), and the support member (50) forms a circumferential surface (51) around the support member (50), and by positioning the support member (50) in the hole (54), the circumferential surface produces an interference fit with the side wall (52) of the hole (54) defined in the structure (16).

[0060] Clause 12. The protective cap assembly (10, 10') according to any one of clauses 1 to 11, wherein the protruding member (28) is composed of a thermoplastic material.

[0061] Clause 13. A protective cap system (56, 56') for enclosing an end (12) of a fastener (14) extending through a structure (16) of an aircraft, the protective cap system comprising:

[0062] A cap member (18) having a side wall (20) defining:

[0063] an opening (22) and an interior space (24), wherein the opening (22) is aligned with the interior space (24) to receive an end (12) of a fastener (14) through the opening (22) and into the interior space (24); and

[0064] an end surface (26) adjacent to the structure (16); and

[0065] A protruding member (58, 58') separate from the cap member (18), wherein:

[0066] The protruding members (58, 58') are constructed of a thermoplastic material; and

[0067] By positioning the protruding member (58, 58') within the opening (46) defined in the structure (16), the end surface (26) is positioned in overlying relationship with the protruding member (58, 58').

[0068] Item 14. A protective cap system (56) according to Item 13, wherein the protruding member (58) includes a wall member (60) configured to have an annular configuration and having a predetermined wall thickness dimension (T) to create an interference fit by positioning the wall member (60) in an opening (46) including a channel (47) defined in the structure (16).

[0069] Clause 15. The protective cap system (56) of clause 14, wherein the wall member (60) has a diameter (D2) such that the end face (26) covers the wall member (60) by positioning the end face (26) on the structure (16).

[0070] Clause 16. A protective cap system (56') according to clause 13 or 14, wherein the protruding member (58') includes a support member (62) defining a predetermined diameter (D3), and the support member (62) forms a circumferential surface (64) around the support member (60), and the circumferential surface forms an interference fit with the side wall (66) of the opening (46) by positioning the support member (60) in the hole (68), and the opening (46) includes a hole (68) defined in the structure (16).

[0071] Clause 17. The protective cap system (56') of clause 16, further comprising a plurality of support members (62) positioned within a plurality of holes (68) defined in the structure (16) and positioned to be spaced apart from one another such that the cap member (18) covers the plurality of support members (62) by positioning the cap member (18) on the structure (16).

[0072] Clause 18. A method (70) for installing a protective cap assembly (10, 10') for enclosing an end (12) of a fastener (14) extending through a structure (16) of an aircraft, the method comprising the steps of:

[0073] The protective cap assembly (10, 10') is positioned (72) on the structure (16) enclosing the end (12) of the fastener (14), wherein:

[0074] A protective cap assembly (10, 10') includes a cap member (18) having a side wall (20) defining:

[0075] an opening (22) and an interior space (24), wherein the opening (22) and the interior space (24) are aligned to receive an end (12) of a fastener (14) through the opening (22) and into the interior space (24) by positioning the protective cap assembly (10, 10'); and

[0076] an end surface (26) that abuts the structure (16) by positioning the protective cap assembly (10, 10');

[0077] as well as

[0078] The protective cap assembly (10, 10') includes a protruding member (28) constructed of a thermoplastic material, the protruding member being secured to and extending from an end face (26) of the cap member (18) such that the protective cap assembly (10, 10') is positioned such that the protruding member (28) enters an opening (46) defined by the structure (16);

[0079] applying (74) one of heat or ultrasound to the thermoplastic material of the protruding member (28) to melt the thermoplastic material; and

[0080] The thermoplastic material of the protruding member (28) is cooled (76) so that the thermoplastic material of the protruding member (28) hardens and adheres to the cap member (18) and the structure (16), thereby securing the cap member (18) to the structure (16).

[0081] Clause 19. A method (78) for installing a protective cap system (56, 56') for enclosing an end (12) of a fastener (14) extending through a structure (16) of an aircraft, the method comprising the steps of:

[0082] positioning (80) a protruding member (58, 58') of a protective cap system (56, 56') constructed of thermoplastic material into an opening (46) defined in the structure (16),

[0083] Positioning (82) a cap member (18) of a protective cap system (56, 56') on a structure (16), the cap member being separate from the protruding member (58, 58'), wherein the cap member (18) has a side wall (20) defining:

[0084] an opening (22) and an interior space (24), wherein the opening (22) is aligned with the interior space (24) such that the end (12) of the fastener (14) extends through the opening (22) and into the interior space (24) by positioning the cap member (18) on the structure (16); and

[0085] an end surface (26) that abuts the structure (16) and covers the protruding members (58, 58') by positioning the cap member (18) on the structure (16);

[0086] applying (84) one of heat or ultrasound to the thermoplastic material of the protruding member (58, 58') to melt the thermoplastic material; and

[0087] The thermoplastic material of the protruding member (58, 58') is cooled (86) so that the thermoplastic material of the protruding member (58, 58') hardens and adheres to the end surface (26) of the cap member (18) and the structure (16), thereby securing the cap member (18) to the structure (16).

[0088] Clause 20. A method (88) for installing a protective cap (19) for enclosing an end (12) of a fastener (14) extending through a structure (16) of an aircraft, the method comprising the steps of:

[0089] Positioning (90) a protective cap (19) on the structure (16), wherein the protective cap (19) has a side wall (20) defining:

[0090] an opening (22) and an interior space (24), wherein the opening (22) is aligned with the interior space (24) such that the end (12) of the fastener (14) extends through the opening (22) and into the interior space (24) by positioning the protective cap (19) on the structure (16); and

[0091] an end portion (96) of the side wall (20) of the protective cap (19) constructed of thermoplastic material, the end portion including an end surface (26) that abuts the structure (16) upon positioning the protective cap (19) on the structure (16); and

[0092] applying (92) one of heat or ultrasound to the end (96) of the side wall (20) of the protective cap (19) and melting the thermoplastic material of the end (96); and

[0093] The end portion (96) of the side wall (20) of the protective cap (19) is cooled (94) so that the thermoplastic material of the end portion (96) of the side wall hardens and adheres to the structure (16) and the remaining portion (98) of the side wall (20) of the protective cap (19), thereby securing the protective cap (19) to the structure (16).

[0094] Although various embodiments have been described above, the present disclosure is not intended to be limited thereto. Modifications may be made to the disclosed embodiments while still falling within the scope of the appended claims.

Claims

1. A protective cap assembly (10, 10') for enclosing an end (12) of a fastener (14) extending through a structure (16) of an aircraft, the protective cap assembly comprising: A cap member (18) having a sidewall (20) defining: an opening (22) and an interior space (24), wherein the opening (22) is aligned with the interior space (24) to receive the end (12) of the fastener (14) through the opening (22) and into the interior space (24); as well as an end surface (26) adjacent to the structure (16); as well as a protruding member (28) fixed to and extending from the end surface (26) of the side wall (20) of the cap member (18), wherein the end surface (26) of the side wall (20) has a width dimension (W) extending from an inner edge (30) of the side wall (20) defining the opening (22) to an outer edge (32) of the side wall (20), and The protruding member (28) is located between the inner edge (30) and the outer edge (32) of the end surface (26).

2. The protective cap assembly (10, 10') according to claim 1, wherein the protruding member (28) extends in a direction (D) transverse to the end face (26).

3. The protective cap assembly (10) according to any one of claims 1-2, wherein the protruding member (28) includes a wall member (34), the wall member having an inner wall surface (36) and an outer wall surface (42), the inner wall surface being at a first radial distance (38) from a central axis (40) of the cap member (18), and the outer wall surface (42) being at a second radial distance (44) from the central axis (40), wherein the second radial distance (44) is greater than the first radial distance (38).

4. The protective cap assembly (10) of claim 3, wherein the wall member (34) extends annularly about the central axis (40) of the cap member (18).

5. The protective cap assembly (10) of claim 3, wherein a width dimension (W1) of the wall member (34) between the inner wall surface (36) and the outer wall surface (42) is a predetermined dimension such that an interference fit is created by positioning the wall member (34) in an opening (46) defined in the structure (16).

6. The protective cap assembly (10') according to any one of claims 1-2, wherein the protruding member (28) comprises a post member (50) positioned to extend from the end surface (26) of the side wall (20).

7. The protective cap assembly (10') according to claim 6, further comprising a plurality of support members (50) spaced apart from each other.

8. The protective cap assembly (10') of claim 7, wherein the plurality of support members (50) are spaced apart from one another and positioned about a central axis (40) of the cap member (18).

9. The protective cap assembly (10') according to claim 7, wherein the support member (50) defines a predetermined diameter (D1), and the support member (50) forms a circumferential surface (51) around the support member (50), and the circumferential surface (51) produces an interference fit with the side wall (52) of the hole (54) defined in the structure (16) by positioning the support member (50) in the hole (54).

10. The protective cap assembly (10, 10') according to any one of claims 1-2, wherein the protruding member (28) is composed of a thermoplastic material.

11. A method (70) for installing a protective cap assembly (10, 10') for enclosing an end (12) of a fastener (14) extending through a structure (16) of an aircraft, the method comprising the steps of: A protective cap assembly (10, 10') is positioned (72) on the structure (16) enclosing the end (12) of the fastener (14), wherein: The protective cap assembly (10, 10') includes a cap member (18) having a side wall (20) defining: an opening (22) and an interior space (24), wherein the opening (22) is aligned with the interior space (24) to receive the end (12) of the fastener (14) through the opening (22) and into the interior space (24) by positioning the protective cap assembly (10, 10'); and an end surface (26) that abuts the structure (16) by positioning the protective cap assembly (10, 10'); and The protective cap assembly (10, 10') includes a protruding member (28) constructed of a thermoplastic material, the protruding member being secured to and extending from the end face (26) of the cap member (18) such that the protective cap assembly (10, 10') is positioned such that the protruding member (28) enters an opening (46) defined by the structure (16); applying (74) one of heat or ultrasound to the thermoplastic material of the protruding member (28) to melt the thermoplastic material; and The thermoplastic material of the protruding member (28) is cooled (76) so that the thermoplastic material of the protruding member (28) hardens and adheres to the cap member (18) and the structure (16) such that the cap member (18) is secured to the structure (16).

12. A method (78) for installing a protective cap system (56, 56') for enclosing an end (12) of a fastener (14) extending through a structure (16) of an aircraft, the method comprising the steps of: positioning (80) a protruding member (58, 58') of the protective cap system (56, 56') constructed of thermoplastic material into an opening (46) defined in the structure (16), Positioning (82) a cap member (18) of the protective cap system (56, 56') on the structure (16) with the cap member separated from the protruding member (58, 58'), wherein the cap member (18) has a side wall (20) defining: an opening (22) and an interior space (24), wherein the opening (22) is aligned with the interior space (24) such that the end (12) of the fastener (14) extends through the opening (22) and into the interior space (24) by positioning the cap member (18) on the structure (16); and an end surface (26) adjacent the structure (16) and superposed on the protruding member (58, 58') by positioning the cap member (18) on the structure (16); applying (84) one of heat or ultrasound to the thermoplastic material of the protruding member (58, 58') to melt the thermoplastic material; as well as Cooling (86) the thermoplastic material of the protruding member (58, 58') causes the thermoplastic material of the protruding member (58, 58') to harden and adhere to the end surface (26) of the cap member (18) and the structure (16), thereby securing the cap member (18) to the structure (16).

13. A method (88) for installing a protective cap (19) for enclosing an end (12) of a fastener (14) extending through a structure (16) of an aircraft, the method comprising the steps of: Positioning (90) the protective cap (19) on the structure (16), wherein the protective cap (19) has side walls (20) defining: an opening (22) and an interior space (24), wherein the opening (22) is aligned with the interior space (24) such that the end (12) of the fastener (14) extends through the opening (22) and into the interior space (24) by positioning the protective cap (19) on the structure (16); and an end portion (96) of the side wall (20) of the protective cap (19) constructed of thermoplastic material, the end portion including an end surface (26) that abuts the structure (16) upon positioning the protective cap (19) on the structure (16); as well as securing a protruding member comprised of the thermoplastic material to the end surface and positioning the protruding member to extend within the opening of the structure; applying (92) one of heat or ultrasound to the end (96) of the side wall (20) of the protective cap (19) and melting the thermoplastic material of the end (96); and Cooling (94) the end portion (96) of the side wall (20) of the protective cap (19) so that the thermoplastic material of the end portion (96) of the side wall hardens and adheres to the structure (16) and the remaining portion (98) of the side wall (20) of the protective cap (19), thereby securing the protective cap (19) to the structure (16).

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