• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    method, fastener, and gripping system. fasteners are inserted into a stack of elements and terminated with parts having at least one of a dry dielectric coating and a dielectric seal at selected locations to protect against electromagnetic (eme) effects.
    公开号:BR112014021234B1
    申请号:R112014021234-1
    申请日:2013-02-28
    公开日:2021-06-15
    发明作者:Richard P. Whitlock；Randall A. Rogers；Peter A. Coronado；Sean D. Morden
    申请人:The Boeing Company；
    IPC主号:
    专利说明:

    FUNDAMENTALS
    [0001] Lightweight composite materials are promising for the aeronautical industry. Fiber composites provide a significant improvement in specific strength and stiffness over conventional metal alloys. Improved specific strength and stiffness translates into reduced weight, which translates into fuel savings and lower operating costs. Additionally, composites do not corrode like aluminum, and they are more resistant to fatigue.
    [0002] Composite structures in this aircraft do not easily carry away the extreme electrical currents and electromagnetic forces generated by lightning strikes.
    [0003] Aircraft with composite structures can be equipped with protection against electromagnetic effects (EME) from lightning strikes. For example, conductive means may be provided on a surface to divert lightning current away from underlying metal fastener systems. In addition, interstices between fastener parts and interstices between fastener parts and structural elements can be filled with dielectric sealant. Even if any current is not deflected, the seal prevents arcing and sparking through the gaps.
    [0004] The seal provides protection against EME. However, the seal injection process is time consuming as it involves multiple steps, including surface cleaning, curing the seal and removing excess filler. Additionally, the seal adds weight to an aircraft. The weight added to a single fastener system could seem insignificant. However, applying sealant to tens of thousands of fasteners in a single aircraft can add hundreds of pounds. SUMMARY
    [0005] According to an embodiment provided herein, one method comprises inserting fasteners into a stack of elements and terminating the fasteners with parts having at least one of a dry dielectric coating and a dielectric seal at selected locations to protect against electromagnetic effects (EME ).
    [0006] According to another embodiment given here, a fastener comprises a fastener head having a top surface with multiple mechanical interlocking locations that are configured to retain a dielectric layer; and a dry dielectric layer covering the upper surface of the head. The dielectric layer is mechanically interlocked with the interlocking locations.
    [0007] According to another embodiment given here, a part for terminating a fastener comprises a fastener termination body having a central opening, and at least one feature for protection against EME effects. The at least one feature includes at least one of a dielectric coating and a dielectric seal partially covering the center opening at a selected location. The seal is attached to the body. The coating and seal have a thickness and composition to inhibit lightning current. The selected location includes at least one of a distal location and a proximal location.
    [0008] According to another embodiment given here, a gripping system comprises a fastener, at least one fastener termination part, and EME protection features for the fastener and each fastener termination part. EME protection characteristics are taken from the group consisting of a conductive resin coating over a fastener shaft, an interlocked dielectric cover over a fastener head, a dielectric seal over a proximal location of the fastener head, a dielectric seal over a fastener head. distal location of the termination portion, a dielectric seal over a location proximal to the termination portion, a dielectric coating over a location distal to the termination portion, and a dielectric coating over a location proximal to the termination portion.
    [0009] In summary, according to one aspect of the invention, a method is provided including inserting fasteners into a stack of elements and terminating the fasteners with parts having at least one of a dry dielectric coating and a dielectric seal at selected locations for protection against electromagnetic effects (EME). Advantageously, the method includes a seal that is used for protection against arcing, sparking and ejection of hot particles, and where the coating is used for protection against arcing and sparking. Advantageously, the method so that the elements are aircraft elements, at least one of which is made of composite material. Advantageously, the method in which the elements include aircraft coating and a metal element. Advantageously, the method wherein inserting at least one of the fasteners includes installing a fastener shaft into a through hole in the stack, the shaft coated with a dry resin including electrically conductive particles. Advantageously, the method wherein inserting at least one of the fasteners includes installing a fastener shaft into a through hole in the stack, the fastener including a head and a dielectric seal at a proximal location on the head. Advantageously, the method wherein inserting at least one of the fasteners includes inserting a fastener head having an upper surface with multiple mechanical interlock locations that are configured to retain a dielectric layer, the dielectric layer covering the upper surface of the head, the dielectric mechanically interlocked with the interlocking locations. Advantageously, the method in which terminating a fastener includes terminating the fastener with a body having a central opening and at least one feature for protection against EME effects, the at least one feature being at least one of a dry dielectric coating and a dielectric seal only over a selected portion of the central opening, the seal secured to and projecting axially from the body.
    [00010] Advantageously, the method may further include adding a conductive layer to an upper surface of the stack prior to carrying out the fixing.
    [00011] According to another aspect of the invention there is provided a fastener including a fastener head having an upper surface with multiple mechanical interlock locations that are configured to retain a dielectric layer, and a dry dielectric layer covering the upper surface of the head, the dielectric layer mechanically interlocked with the interlocking sites.
    [00012] Advantageously, the dielectric layer, the head, and a fastener shaft extend from the head. Advantageously, each interlocking location includes a projection extending upwards from the upper surface and having an undercut portion, proximate to the upper surface.
    [00013] Advantageously, the interlocking locations are arranged in a grid pattern. Advantageously, the interlocking locations are arranged as spokes in a radial pattern. Advantageously, the surface has roughness to improve retention to the dielectric layer. Advantageously, between five and nine interlocking locations protrude from the top surface. Advantageously, the dielectric layer is in intimate contact with the upper surface and interlocking sites. Advantageously, the fastener may further include a shaft coated with a dry resin including electrically conductive particles. Advantageously, the fastener may further include a dielectric seal at a proximal location on the fastener head.
    [00014] According to yet another aspect of the invention there is provided part for terminating a fastener including a fastener termination body having a central opening, and at least one feature for protection against EME effects, the at least one feature including at least one of a dielectric coating and a dielectric seal partially covering the center opening at a selected location, the seal secured to the body, the coating and seal having a thickness and composition to inhibit lightning current, The selected location including at least one of one distal site and a proximal site. Advantageously, the seal protrudes axially at least 0.17 mm (7 mils) from the body. Advantageously, the part may further include a dielectric coating completely covering an outer surface of the body. Advantageously, the body includes a nut. Advantageously, the dielectric seal is at a distal location on the nut. Advantageously, the part may further include a dielectric seal at an outer proximal location on the nut.
    [00015] Advantageously, at least one feature includes both the dielectric coating and the dielectric seal. Advantageously, the body includes a washer. Advantageously, the feature includes a seal at the inner proximal location of the washer. Advantageously, the feature further includes a second seal at a distal location, the seals separated by an interstice. Advantageously, the part may further include a dielectric coating on an outer surface of the washer. Advantageously, the part may further include a concentric ridge protruding from at least one face of the washer.
    [00016] According to another aspect of the present invention there is provided a gripping system comprising a fastener, at least one fastener termination part, and EME protection features for the fastener and each fastener termination part, the characteristics of EME protection group outlets consisting of: a conductive resin coating over a fastener shaft, an interlocked dielectric cover over a fastener head, a dielectric seal over a proximal location of the fastener head, a dielectric seal over a distal location of the termination portion, a dielectric seal over a location proximal to the termination portion, a dielectric coating over a location distal to the termination portion, and a dielectric coating over a location proximal to the termination portion. Advantageously, the dielectric seal is used to protect against arcing, sparking and ejection of hot particles; and where the dielectric coating is used to protect against arcing and sparking.
    [00017] These features and functions can be obtained independently in various modalities or can be combined with other modalities. Further details of the modalities can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS
    [00018] FIG. 1 is an illustration of a method of attaching a stack of elements.
    [00019] FIG. 2 is an illustration of a commercial aircraft.
    [00020] FIGS. 3A and 3B are illustrations of a first embodiment of an EME protective fastener.
    [00021] FIGS. 4A and 4B are illustrations of a second embodiment of an EME protective fastener.
    [00022] FIGS. 5 and 6 are illustrations of other modalities of protective EME fasteners.
    [00023] FIG. 7 is an illustration of a stack including a composite element and a conductive layer.
    [00024] FIG. 8 is an illustration of selected EME protection locations on a nut.
    [00025] FIGS. 9-12 are illustrations of different modalities of washers and nuts having EME protection characteristics and different combinations of washers and nuts.
    [00026] FIG. 13 is an illustration of an aircraft structure. DETAILED DESCRIPTION
    [00027] Reference is made to FIG. 1 illustrating a method of attaching a stack of elements. The stack has two or more elements. In some embodiments, all of the elements in the stack are made of metal (eg, aluminum, titanium). In other embodiments, at least one of the elements in the stack is made of composite material. For example, an outer element is made of composite material and an inner element is made of metal. In other embodiments, all of the elements in the stack can be made of composite material. The method includes inserting fasteners into the stack (block 110). In some embodiments, fasteners are inserted into pre-formed through holes in the stack. In other embodiments, fasteners are inserted without drilling holes. Fasteners can be countersunk into external elements whose external surfaces require smoothing (eg, aircraft coating). Fasteners can have protective characteristics against EME including dry dielectric layers interlocked to the upper surfaces of fastener heads, and dielectric seals on the lower surfaces of the fastener heads.
    [00028] The method further includes terminating fasteners with parts having protective characteristics against EME. EME protective features for termination parts include dry dielectric coatings and dielectric seals (eg dielectric gloves) at selected locations (block 120).
    [00029] Without these EME protection features, arcing and arcing can occur. Arcing occurs when two metal parts are in close contact, and dielectric properties of the medium between break due to high current flowing between the parts. Sparking occurs when a high current ionizes air in an interstice between two parts, the air breaks up, and current flows through the interstice. Hot particle ejection occurs when a high current in a composite part causes the composite material to chemically dissociate and generate hot expansion gas.
    [00030] Both the dielectric coating and the dielectric seal prevent arcing and sparking by blocking the electrical connection path between parts. Dielectric coating and dielectric sealing, alone and in combination, inhibit arcing and arcing through interstices between fastener parts (eg, interstice between fastener and nut, and interstice between washer and nut) and interstices between fastener parts and frame (eg, interstices between fastener and frame, nut and frame, and washer and frame). The dielectric seal performs the additional function of preventing hot gas from being ejected through the interstices and keeping the gas within the gripping system.
    [00031] In addition to, or alternatively, some modalities of fasteners can reduce arcing, sparking and hot particle ejection by improving the electrical bonding path. In these embodiments, the fastener shafts can be coated with a conductive coating (eg, a conductive resin) to improve the electrical bond between the fastener and stack and thus reduce contact resistance. In some embodiments, the fasteners can be loosely fitted into the holes. In other embodiments, fasteners may be interference fit into the holes. Interference fit improves the electrical bond between fastener and stack (by increasing surface contact area), which reduces current densities and lowers overall path resistance.
    [00032] The use of dry dielectric coating on parts of a fastener system offers several advantages over using a sealant to fill the interstices. Advantages include ease and speed of installation. The dry dielectric can be coated onto the fastener parts prior to installation, so that during clamping, the fasteners only need to be fitted. Additional steps, such as masking of stack parts, sealant injection, and sealant curing, are eliminated. Another advantage is a reduction in weight. Dry dielectric coatings and seals can be thinner than sealant layers. In some embodiments, the thickness of the dielectric coating or seal may be 0.7 mm +- 0.2 mm (30 mils +-10 mils). In addition, less surface area is covered since an entire surface of a fastener portion is not covered with a dry dielectric coating or dielectric seal. Another advantage is redundant protection against EME. Different modalities of fasteners can be used in combination with different modalities of termination parts (eg nuts and washers) to provide multiple levels of protection against EME.
    [00033] These advantages are substantial over a commercial aircraft such as the commercial aircraft 200 illustrated in FIG. 2. Aircraft 200 includes a fuselage 210, wing assemblies 220, empennage 230, and landing gear assemblies 240. In this commercial aircraft 200, one million fastener systems could be used to hold together the various components 210-240 and its subcomponents.
    [00034] At certain locations on the 200 aircraft, protection from EME is desirable. For example, EME protection is desirable for wing assemblies and other structures. To provide protection against EME, 220 wing assemblies can be fitted with as much as 20,000 fasteners according to a method given here. The advantages realized by the reduced weight and time and ease of installation of those 20,000 fasteners are very substantial.
    [00035] In the following paragraphs, different types of EME protective fastener parts will be described. These fastener parts include fasteners and parts that terminate fasteners (for example, nuts and washers). These fastener parts may have dry dielectric coatings and/or dielectric seals at selected locations for protection against EME.
    [00036] First, EME protective fasteners will be described. Examples of fasteners include, but are not limited to screws and rivets.
    [00037] Reference is now made to FIGS. 3A and 3B, which illustrate a first embodiment of an EME protective fastener 310. FIG. 3B is a sectional view taken along lines 3B-3B in FIG. 3A. Fastener 310 includes a head 320 and a shaft 330. An upper surface 322 of fastener head 320 has multiple mechanical interlock locations that are configured to retain a dielectric layer 340. Each interlock location includes an upwardly extending projection 324 from top surface 322. Projection 324 has a countersunk portion 326 proximate top surface 322. In the embodiment of FIGS. 3A and 3B, the projections 324 may be spokes 324 that extend radially outward and have a cross section of an inverted triangle. Fastener 310 further includes a dielectric layer 340 covering fastener head 320. Dielectric layer 340 is not limited to any particular dielectric material. Examples include, but are not limited to, thermosets, thermoplastics, rubber, ceramics, and elastomers.
    [00038] The dielectric layer 340 fills the ribbed portions and any other space between the projections 324. The dielectric 340 is also in intimate contact with the upper surface 322 and the projections 324.
    [00039] In some embodiments, the dielectric layer 340 can be formed by flowing a dielectric material over the fastener head 320. When the dielectric material flows over the surface 322, it fills the undercuts or ridges 326 and all the space between the projections 324. Once the dielectric material hardens, it is interlocked with the projections 324 and thus secured to the fastener head 320. In other embodiments, the dielectric layer 340 can be formed by powder coating, painting, plating, spraying, spraying cathodic, deposition, or any other process that allows the dielectric material to fill the countersunk portions 326.
    [00040] In this way, the dielectric layer 340 is mechanically interlocked with the interlocking locations prior to installation of the fastener. Fastener 310 with dielectric layer 340 is pre-fitted to head 320.
    [00041] The interlocking of the dielectric layer 340 to the fastener head 320 is especially advantageous for lightning strikes. The interlock ensures that the dielectric layer 340 maintains intimate contact with the fastener head 320 during and after such events.
    [00042] The dielectric layer 340 can be retained by additional means. As a first example, surface 322 may have roughness to improve retention of dielectric layer 340. As a second example, dielectric layer 340 may be made of a material (e.g., adhesive sealant) that adheres to surface 322.
    [00043] In other embodiments of EME protective fasteners, the interlocking locations may have other cross sections and they may be arranged in other patterns. Examples of other cross sections include, but are not limited to square and circular cross sections. Cross sections having areas of high stress concentration (eg corners) are not preferred. Rounded cross sections provide better mechanical properties.
    [00044] An EME protective fastener indicated here is not limited to any particular number of interlocking locations. However, a range of five to nine interlock locations has been found to provide a good balance between interlock strength (with the dielectric layer) and fastener tightening strength.
    [00045] Reference is now made to FIGS. 4A and 4B, which illustrate a second embodiment of an EME 410 protective fastener. The EME 410 protective fastener includes interlock locations 420 arranged in a grid. Each interlock location 420 includes a shaft 422 that extends upwardly from an upper surface 414 of the fastener head 412. The shaft 422 terminates in a button 424. The shaft 422 and the surfaces between the button 424 and the fastener head fastener 412 define a countersunk portion 426.
    [00046] Reference is now made to FIGS. 5 and 6, which illustrate embodiments of fasteners 510 and 610 including heads 512 and 612 and dielectric seals 520 and 620. Seals 520 and 620 can be mechanically affixed to fastener heads 512 and 612. Seals 520 and 620 are made of one polymeric material such as polytetrafluoroethylene (PTFE), or thermoplastic polymers such as polyether ether ketone (PEEK) and polyamide imides. When fastener 510 or 610 is inserted into a pile and terminated, its seal 520 or 620 makes compressive contact with the pile.
    [00047] In fastener 510 of FIG. 5, seal 520 fits around a periphery of fastener head 512. Seal 520 may have a ridge 522 that fits within a groove in fastener head 512. Seal 520 inhibits arcing and arcing in the fastener 512. edge of clamp head 520, and it prevents hot expansion gas under head 512 from escaping.
    [00048] In fastener 610 of FIG. 6, seal 620 is shaped like an O-ring and fits into a groove on an underside of fastener head 612. Seal 620 inhibits arcing and sparking, and it prevents any expansion gas from escaping heat between the stack and the shaft of the fastener 614. The upper and side surfaces of the fastener head 612 may be covered with a dielectric coating 630 to prevent arcing and sparking at the edge of the fastener head 612. Reference is now made to FIG. 7, which illustrates stack 700 including a composite element 710 and a conductive layer 720 (eg, fastener shaft, expansion sheet) covering composite element 710. An EME protective fastener 750 is inserted into a through hole 730 in a composite element 710 and countersunk within the conductive layer 720. The dielectric layer 752 on the fastener head 754 is flush with the conductive layer 720. In some embodiments, the entire fastener shaft 230 may be coated with a conductive resin coating. seca 756 (shaded in grey) having electrically conductive particles dispersed in a polymer matrix). Examples of conductive particles include, but are not limited to, metal particles, and nanotubes. The resin, in combination with an interference fit, has been found to improve the electrical connection path between the fastener 750 and the composite element 710. The resin fills voids between the fastener shaft 758 and the composite element 710. this, the resin increases the effective contact area with fibers of the composite element 710.
    [00049] When fastener 750 is being finished (eg when a nut is being screwed onto fastener 750), it must not rotate inside through hole 730. To prevent rotation without damaging dielectric layer 752, an anti- rotation can be used. Examples of anti-rotation measures include, but are not limited to, creating an interference (or friction) fit between fastener shaft 758 and element 710; providing axle 758 with a cross-sectional shape that prevents rotation (eg, a hexagonal shape for the axle and through hole), and keying from axle 758 to element 710. Fasteners indicated here may be anywhere on an aircraft. As examples, the fasteners indicated here can be used in door surroundings, housing electrical equipment, and parts that are subject to ground fault currents. Fasteners indicated here can be terminated with standard parts (eg standard nuts) or they can be terminated with EME protective parts on them.
    [00050] In the following paragraphs, different types of fastener termination parts, protective against EME, will be described. These parts include nuts and washers.
    [00051] Reference is now made to FIG. 8, which illustrates a fastener 830 extending through a stack member 800, and a washer 810 and nut 820 terminating fastener 830. FIG. 8 also illustrates several locations on the 810 washer and 820 nut that can be covered with a dry dielectric coated dielectric seal for protection against EME. The locations on the nut 820 include an inner distal location 840, an outer proximal location 850, and an inner proximal location 860. The locations on the washer 810 include an inner proximal location 870 and an inner distal location 880. The terms "proximal" and "distal" refer to the distance from stack 800. For example, the proximal location of nut 820 is closer to stack 800 than the distal location. The terms "inside" and "outside" refer to the distance from the fastener axis.
    [00052] Instead of covering the entire 810 washer and 820 nut with sealant for protection against EME, only one or more of these 840880 locations can be coated or sealed with dry dielectric material.
    [00053] If a seal is used, the seal is secured to a central opening in the body and protrudes axially from the body. In some embodiments, the seal protrudes at least 0.17 mm (7 mils) from the body. The seal can be made of a polymeric material such as polytetrafluoroethylene (PTFE), or thermoplastic polymers such as polyether ether ketone (PEEK) and polyamide imides. The seal can be mechanically affixed using projections and countersinks that allow the polymeric material to flow into the undercuts or countersinks.
    [00054] In some embodiments, an outer surface of the body is completely covered by a dielectric coating. Examples of compositions for the dielectric coating include, but are not limited to, thermosets, thermoplastics, ceramics, glass, and elastomers. Dielectric coating can be applied by a process such as anodic conversion coating (eg, electrolyte to plasma oxidation), which is an electrochemical surface conversion treatment. Other processes for applying the dielectric include, but are not limited to, powder coating, spraying, plating, sputtering, and deposition.
    [00055] Reference is made to FIG. 9, which illustrates a combination including a washer 910 having a seal 920 at the inner proximal location. The distal location is not covered. The outer surface of the washer 910 is coated with a dielectric material.
    [00056] The combination also includes a 950 nut having a seal 960 at the proximal outer location, a seal 970 at the proximal inner location, and a 980 dielectric coating at the distal location. There is no dielectric coating on the outer surface of nut 950. When nut 950 and washer 910 are mated with the stack, the inner proximal seal 920 of the washer 910 is pressed against the stack, and the inner proximal seal 970 of the nut 950 is received in the center opening of washer 910. When nut 950 is tightened, washer seal 920 bends back and is kneaded against the stack, thus filling any void spaces between washer 910 and the stack.
    [00057] Reference is made to FIG. 10, which illustrates a combination including a washer 1010 having a seal 1020 at the inner proximal location; and a nut 1050 having a seal 1060 at the inner proximal location, a dielectric coating 1070 at the distal location, and a dielectric coating 1080 on the outer surface (instead of a seal at the outer proximal location).
    [00058] Reference is made to FIG. 11, which illustrates a combination including a washer 1110 having a seal 1120 at the inner proximal location, and a concentric ridge 1130 formed on a periphery of the washer 1110. The combination also includes a nut 1150 having a seal 1160 at the inner proximal location, a liner 1170 dielectric at the outer surface (instead of a seal at the outer seal location), and an 1180 seal at the inner distal location.
    [00059] When the nut 1150 and the washer 1110 are mated with the stack, the inner proximal seal 1120 and the crest 1130 of the washer 1110 are pressed against the stack, and the inner proximal sleeve 1160 of the nut 1150 is received in the central opening of the washer 1110. When nut 1150 is tightened, inner proximal seal 1120 of washer 1110 bends back and is squashed against the stack. The concentric ridge 1130 also maintains a seal between the washer 1110 and the stack, even if the face of the washer 1110 is not parallel with the bottom face of the stack.
    [00060] Reference is now made to FIG. 12, which illustrates a combination including a washer 1210 having seals 1220 and 1230 at the proximal and distal internal locations. There is a gap between these seals 1220 and 1230. The combination further includes a 1250 nut with a 1270 dielectric coating over the entire outer surface, and a 1260 coating at the inner proximal location.
    [00061] When the 1250 nut and the 1210 washer are mated with the stack, the proximal seal 1220 of the 1210 washer is pressed against the stack, and the distal seal 1230 of the 1210 washer is received at the inner proximal location of the 1250 nut. nut 1250 is tightened, proximal seal 1220 of washer 1210 folds back and is crimped against the stack, and distal seal 1230 of washer 1210 folds back and is crimped against nut 1250.
    [00062] A washer indicated here is not limited to a concentric crest on the periphery. Other modalities of washers may have concentric ridges on intermediate portions and inner portions of the upper face of the washer. Some modalities may have concentric ridges on both faces.
    [00063] In some embodiments, the concentric crest can be formed by stamping a concentric groove into the washer, and filling the groove with a dielectric ring. In other embodiments, a metal ridge may be stamped onto the washer.
    [00064] Although FIGS. 9-12 illustrate nuts 950, 1050, 1150, 1250 that are open at both ends, a nut shown here is not limited thereto. For example, one end of a nut shown here can be closed to form a cap. The cap can be made of a dielectric material, or the cap can be made of metal with its inner surface coated with a dielectric material. Such a cap would provide additional protection against distal arcing and sparking.
    [00065] A fastening system indicated here is not limited to the combinations of fasteners, nuts and washers described above. A variety of EME protection features can be mixed and matched. Multiple parts having different characteristics can be used. For example, EME protection characteristics can be taken from the group consisting of a conductive resin coating on a fastener shaft, an interlocked dielectric cover over a fastener head, a dielectric seal over a proximal location of the fastener head, a dielectric seal over a location distal to the termination portion, a dielectric seal over a location proximal to the termination portion, a dielectric coating over a location distal to the termination portion, and a dielectric coating over a location proximal to the termination portion.
    [00066] Reference is now made to FIG. 13, which illustrates a portion of an aircraft wing 1310. Wing 1310 includes lining 1320 made of a composite material, such as carbon fiber reinforced plastic (CFRP). Coating 1320 can be secured to a sub-frame (represented by bracket) 1330 by metal fastener portions 1340, 1380 and 1390. Coating 1320 defines a lightning-susceptible area 1350.
    [00067] Each 1340 fastener has a 1342 dielectric layer that is interlocked with a 1344 fastener head. Each 1340 fastener may have a conductive resin coating on its 1346 shaft.
    [00068] Each fastener 1340 is countersunk within jacket 1320. Dielectric layer 1342 is flush with the top surface of jacket 1320. A sheet metal 1360 covers jacket 1320 to dissipate EME current. A surface film (eg, an epoxy-glass layer) 1365 is applied over the coating 1320, and the surface film 1365 is covered with paint 1370.
    [00069] Each 1340 fastener is terminated with a 1380 washer and a 1390 nut. The 1380 washer and 1390 nut have various EME protection characteristics.
    [00070] There could be tens of thousands of 1340 fasteners, 1380 washers, and 1390 nuts on the 1310 wing. By using EME protection features here, rather than sealant injection, the reductions in installation time are substantial. The reduction in weight is also substantial.
    [00071] FIG. 13 illustrates the surface of washer 1380 and bracket 1330 being slightly angled. If washer 1380 is provided with a top sleeve or a concentric ridge on the top surface, any gap between washer 1380 and bracket 1370 will be filled with dielectric material and sealed.
    [00072] Similarly, if the 1390 nut is slightly sloped with respect to the 1380 washer, or if a washer is not used and the nut is slightly sloped with respect to the stack, any gap between the nut and washer or nut and stack will be filled with dielectric material and sealed.
    [00073] Thus, the EME protection features provide the additional advantage of making the structure less dependent on geometry. Even if mating surfaces of the termination parts are not perfectly aligned or flush, protection against EME is still provided.
    权利要求:
    Claims (11)
    [0001]
    1. Method comprising inserting fasteners into a stack of elements and terminating the fasteners with parts having at least one of a dry dielectric coating and a dielectric seal at selected locations for protection against electromagnetic effects (EME), in which to insert at least one of the fasteners includes installing a fastener shaft (758) in a through hole in the stack, characterized in that the shaft is coated with a dry resin including electrically conductive particles (756).
    [0002]
    2. Method according to claim 1, characterized in that the seal is used for protection against arcing, sparking and ejection of hot particles; and where the coating is used to protect against arcing and sparking.
    [0003]
    3. Method according to claim 1 or 2, characterized in that the elements are aircraft elements at least one of which is made of composite material.
    [0004]
    4. Method according to any one of claims 1 to 3, characterized in that the elements include aircraft coating and a metal element.
    [0005]
    5. Method according to any one of claims 1 to 4, characterized in that inserting at least one of the fasteners includes installing a fastener shaft in a through hole in the stack, the fastener including a head (612) and a dielectric seal (620) at a proximal location over the head.
    [0006]
    6. Method according to any one of claims 1 to 5, characterized in that inserting at least one of the fasteners includes inserting a fastener head (320) having an upper surface (322) with multiple mechanical interlock locations that are configured to retain a dielectric layer (340), the dielectric layer covering the upper surface of the head, the dielectric mechanically interlocked with the interlocking locations.
    [0007]
    7. Method according to any one of claims 1 to 6, characterized in that terminating a fastener includes terminating the fastener with a body having a central opening and at least one feature for protection against EME effects, the at least one feature at least one of a dry dielectric coating and a dielectric seal only over a selected portion of the central opening, the seal secured to and projecting axially from the body.
    [0008]
    8. Method according to any one of claims 1 to 7, characterized in that the stack comprises a composite member (710) and a conductive layer (720) covering the composite member.
    [0009]
    9. Fastener (750) comprising: a fastener head (754) having an upper surface with multiple mechanical interlocking locations that are configured to retain a dielectric layer; a dry dielectric layer (752) covering the upper surface of the head, the dielectric layer mechanically interlocked with the interlocking sites; and a shaft (758), characterized in that the shaft (758) is coated with a dry resin including electrically conductive particles (756).
    [0010]
    10. Fastener according to claim 9, characterized in that each interlocking location includes a projection extending upward from the upper surface (322) and having an undercut portion (326) near the upper surface.
    [0011]
    11. Fastening system characterized in that it comprises a fastener as defined in claims 9 or 10, at least one fastener termination part, and EME protection features for the fastener and each fastener termination part, the protection features against EME outlets from the group consisting of: a conductive resin coating on a fastener shaft; an interlocked dielectric cover over a fastener head; a dielectric seal over a proximal location of the fastener head; a dielectric seal over a distal location of the termination portion; a dielectric seal over a site proximal to the termination portion; a dielectric coating over a distal location of the termination portion; and a dielectric coating over a location proximal to the termination portion.
    类似技术:
    公开号 | 公开日 | 专利标题
    BR112014021234B1|2021-06-15|METHOD, FASTENER, AND, GRIP SYSTEM
    US9611052B2|2017-04-04|Fastener systems that provide EME protection
    AU2017210586B2|2018-11-15|Fastener systems that provide EME protection
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    US8995108B2|2015-03-31|Coupling structure for airframe components
    GB2557962A|2018-07-04|Cap for a fastener
    CN210769890U|2020-06-16|Flange butt joint structure and insulating pillar
    DE10200564A1|2003-07-24|Lightning protection system, for a combination of a structural element and an attached closure element, comprises a net consisting of a metal or plastic composite with electrically conductive fibers on its surface
    CN108799274A|2018-11-13|The method and apparatus for providing anti-corrosion protection for connection surface
    同族专利:
    公开号 | 公开日
    CA3043408A1|2013-11-28|
    JP6253635B2|2017-12-27|
    KR101975073B1|2019-05-03|
    CA2865161A1|2013-11-28|
    RU2014131315A|2016-05-20|
    CA2865161C|2019-10-08|
    JP2018071790A|2018-05-10|
    JP6534723B2|2019-06-26|
    US9802715B2|2017-10-31|
    ES2636790T3|2017-10-09|
    CN104245511A|2014-12-24|
    EP2830948B1|2017-05-10|
    CN104245511B|2017-02-22|
    EP2830948A2|2015-02-04|
    WO2013176722A3|2014-01-30|
    US20130259604A1|2013-10-03|
    KR20140147081A|2014-12-29|
    CA3043408C|2021-03-02|
    RU2629097C2|2017-08-24|
    US20170275019A1|2017-09-28|
    JP2015514190A|2015-05-18|
    WO2013176722A2|2013-11-28|
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    法律状态:
    2018-12-04| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2019-11-19| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2021-05-11| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-06-15| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 28/02/2013, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    US13/434,835|2012-03-29|
    US13/434,835|US9802715B2|2012-03-29|2012-03-29|Fastener systems that provide EME protection|
    PCT/US2013/028413|WO2013176722A2|2012-03-29|2013-02-28|Fastener systems that provide eme protection|
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