Multi-piece fastener and fastening method

Abstract

A multi-piece fastener and fastening method are provided. The multi-piece fastener comprises a fastening collar and a pin. The fastening collar comprises an inner collar surface defining a collar cavity, an outer collar surface, a coating on the outer collar surface, and a lubricating layer intermediate the coating and the outer collar surface. The coating comprises a resin and a metal pigment. The pin is configured to be at least partially received by the collar cavity. The pin comprises a first pin end, a second pin end, and a shank extending intermediate the first pin end and the second pin end. The fastening collar is configured to be deformed onto the shank by forcing the outer collar surface of the fastening collar into contact. Forcing the outer collar surface into contact at least partially removes the coating on the outer collar surface and indicates installation of the multi-piece fastener.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 264,667, filed November 30, 2021, the contents of which are hereby incorporated by reference herein.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates to multi-piece fasteners and fastening methods. [Background technology]

[0003] Vehicle frames, storage racks, solar panel substructures, aircraft parts, and other structures may include numerous mechanical fasteners. For example, structural fasteners may be installed into holes in structural components to secure the parts together. Properly installing structural fasteners into holes can be challenging. Summary of the Invention [Means for solving the problem]

[0004] According to one non-limiting aspect of the present disclosure, a multi-piece fastener is provided. The multi-piece fastener includes a fastening collar and a pin. The fastening collar includes an inner collar surface defining a collar cavity, an outer collar surface, a coating on the outer collar surface, and a lubricating layer intermediate the coating and the outer collar surface. In certain non-limiting embodiments, the fastening collar further includes a corrosion-resistant layer intermediate the coating and the outer collar surface. The coating includes a film-forming resin and a metallic pigment. The pin is configured to be at least partially received by the collar cavity. The pin includes a first pin end, a second pin end, and a shank extending intermediate the first and second pin ends. In various non-limiting embodiments, the shank includes at least one of a generally smooth region, an annular shoulder, a groove, and a threaded region. In certain non-limiting embodiments, the diameter of the shank is in the range of 0.06 inches to 4 inches. The fastening collar is configured to be deformed onto the shank by forcing the outer collar surface of the fastening collar into contact. Forcing the outer collar surfaces into contact at least partially removes the coating on the outer collar surfaces, indicating installation of the multi-piece fastener. In certain non-limiting embodiments, the coating does not increase the coefficient of friction of the outer collar surfaces of the fastening collar.

[0005] In various non-limiting embodiments of multi-piece fasteners according to the present disclosure, the coating further comprises one or both of a fluorescent dye and a fluorescent pigment. In certain non-limiting embodiments, the metallic pigment comprises aluminum, an aluminum alloy, or a combination thereof. In certain non-limiting embodiments, the coating comprises 0.01% by weight or less of titanium dioxide, based on the total weight of the coating, and / or 0.01% by weight or less of a metal oxide, based on the total weight of the coating. In various non-limiting embodiments, the CIELAB L of at least a region of the outer collar surface of the fastening collar of the multi-piece fastener is * The value is 10 or less when measured with an integrating sphere spectrophotometer under D65 illumination, at a 10° viewing angle, and with the specular reflection component removed.

[0006] In various non-limiting embodiments of multi-piece fasteners according to the present disclosure, the fastening collar further comprises a flange and the coating is absent on the flange. In certain non-limiting embodiments, the coating is in the form of a strip and / or has an opacity of at least 25%.

[0007] In various non-limiting embodiments of a multi-piece fastener according to the present disclosure, the multi-piece fastener is configured to be installed into a hole in a structure, the structure being at least one of an aircraft part or component, an automotive part or component, a transportation part or component, and a building and construction part or component. In certain non-limiting embodiments, the multi-piece fastener comprises at least one of a metal and a metal alloy. In various non-limiting embodiments, a lockbolt is provided comprising a multi-piece fastener according to the present disclosure.

[0008] According to another non-limiting aspect of the present disclosure, a method for fastening is provided. A multi-piece fastener may have, for example, a structure according to the present disclosure. In various embodiments of the method according to the present disclosure, the multi-piece fastener includes a fastening collar and a pin. In certain embodiments, the fastening collar may include an inner collar surface defining a collar cavity, an outer collar surface, a coating on the outer collar surface, and a lubricating layer intermediate the coating and the outer collar surface. The coating includes a resin and a metal pigment. The pin includes a first pin end, a second pin end, and a shank extending intermediate the first and second pin ends, and is configured to be at least partially received by the collar cavity. The method includes at least partially inserting the pin into the collar cavity and forcing the outer collar surface of the fastening collar into contact with an anvil of a fastening collar attachment, thereby deforming the fastening collar onto the shank of the pin. Forcibly contacting the outer collar surface at least partially removes the coating on the outer collar surface, e.g., indicating installation of a multi-piece fastener such that at least 90% of the total visible surface area of ​​the coating is removed from the outer collar surface of the fastening collar.

[0009] It will be understood that the invention disclosed and described herein is not limited to the aspects outlined in this Summary. The reader will understand these and other details in light of the following detailed description of various non-limiting and non-exhaustive aspects hereof. [Brief explanation of the drawings]

[0010] The features and advantages of the non-limiting embodiments presented herein, and the manner in which they are achieved, will become more apparent and the embodiments will be better understood by referring to the following description in conjunction with the accompanying drawings.

[0011] [Figure 1] FIG. 1 is a perspective view of a non-limiting embodiment of a multi-piece fastener according to the present disclosure. [Figure 2] FIG. 2 is a cross-sectional side view of a non-limiting embodiment of a multi-piece fastener and fitting according to the present disclosure, showing the multi-piece fastener in a hole in a structure and in a first configuration. [Figure 3] FIG. 3 is a cross-sectional side view of the multi-piece fastener and fitting of FIG. 2 showing the multi-piece fastener in a hole in a structure and in a second configuration. [Figure 4] FIG. 4 is a flow chart of a non-limiting embodiment of a method for fastening according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Corresponding reference characters indicate corresponding parts throughout the several views. The examples set forth herein illustrate particular embodiments in one form, and such examples should not be construed as limiting the scope of the appended claims in any manner.

[0013] DETAILED DESCRIPTION OF NON-LIMITING EMBODIMENTS Various embodiments are described and illustrated herein to provide a thorough understanding of the structure, function, and use of the disclosed fastening collars, multi-piece fasteners, and fastening methods. The various embodiments described and illustrated herein are non-limiting and non-exhaustive. Accordingly, the present invention is not limited by the description of the various non-limiting and non-exhaustive embodiments disclosed herein. Rather, the present invention is defined solely by the claims. Features and characteristics illustrated and / or described in connection with various embodiments may be combined with features and characteristics of other embodiments. Such modifications and variations are intended to be included within the scope of this specification. Accordingly, the claims may be amended to recite any feature or characteristic explicitly or inherently described herein, or otherwise explicitly or inherently supported by this specification. Further, applicants reserve the right to amend the claims to approvingly disclaim any feature or characteristic that may exist in the prior art. The various embodiments disclosed and described herein may comprise, consist of, or consist essentially of the features and characteristics variously described herein.

[0014] Any reference herein to "various embodiments," "some embodiments," "one embodiment," "one embodiment," "non-limiting embodiment," or similar phrases means that a particular feature, structure, or characteristic described in connection with an example is included in at least one embodiment. Thus, appearances of the phrases "various embodiments," "some embodiments," "one embodiment," "in one embodiment," "non-limiting embodiment," or similar phrases herein do not necessarily refer to the same embodiment. Furthermore, particular described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, a particular feature, structure, or characteristic illustrated or described in connection with one embodiment may be combined, in whole or in part, without limitation, with the feature, structure, or characteristic of one or more other embodiments. Such modifications and variations are intended to be included within the scope of the present embodiments.

[0015] As used herein, "intermediate" means that the referenced element is disposed between two other elements, but is not necessarily in contact with the other components. Thus, unless otherwise stated herein, an element "intermediate" between a first element and a second element may or may not be adjacent to, or in contact with, the first and / or second element, and additional elements may be disposed between the intermediate element and the first and / or second element.

[0016] For example, a structural fastener, such as a lockbolt, may be installed into a hole in a structure by using an installation tool to deform (e.g., swage) the collar of the lockbolt over a segment of the fastener's pin. Depending on the user and / or installation tool, for example, the collar may not deform at all during installation of such a fastener, or may not deform to the extent necessary to properly install the fastener in place. To address this possibility, the present disclosure provides multi-piece fasteners and fastening methods that allow for efficient visual verification of proper installation of structural fasteners during the installation procedure. The multi-piece fasteners and methods described herein can increase the accuracy and / or overall efficiency of the manufacturing process by providing rapid visual verification of proper fastener installation.

[0017] FIG. 1 illustrates a non-limiting embodiment of a multi-piece fastener 100 according to the present disclosure. The multi-piece fastener 100 may be configured to be installed in a hole in a structure (e.g., as illustrated in FIGS. 2-3 discussed below). The multi-piece fastener 100 may comprise at least two components, such as a fastening collar 102 and a pin 120, as illustrated in FIG. 1, or in some non-limiting embodiments, at least three components (not shown). In various non-limiting embodiments, the multi-piece fastener 100 may comprise a two-piece assembly including the fastening collar 102 and the pin 120. In various non-limiting embodiments, the multi-piece fastener 100 may be at least one of a lockbolt and a blind fastener. For example, the lockbolt may be a structural lockbolt fastener, such as a structural rivet, a structural bolt, or a structural stud.

[0018] The fastening collar 102 may include a first collar end 104, a second collar end 106, an extended portion 108 disposed intermediate the first collar end 104 and the second collar end 106, an inner collar surface 116a, and an outer collar surface 116b. The inner collar surface 116a defines a cavity 110 extending through the extended portion 108 from the first collar end 104 to the second collar end 106. The extended portion 108 may define a longitudinal axis of the fastening collar 102. The inner collar surface 116a may be adjacent to the cavity 110 and may include at least one of a substantially cylindrical region, a threaded region, an annular shoulder, and a groove, depending on the desired application. In various non-limiting embodiments, the fastening collar 102 may be generally cylindrical.

[0019] In various non-limiting embodiments, the fastening collar 102 may include a flange 118. In certain non-limiting embodiments, the fastening collar 102 may be configured to engage and / or be received by an anvil of a fixture, while the flange diameter of the flange 118 may prevent the fastening collar 102 from passing into a hole in a structure more than a predetermined distance.

[0020] The pin 120 may include a first pin end 128, a second pin end 130, and a shank 122. The shank 122 may include a shape suitable for receipt by the cavity 110 of the fastening collar 102, such as a generally cylindrical shape. The shank 122 may extend intermediate the first pin end 128 and the second pin end 130 and may be sized to be at least partially disposed within the cavity 110. When the shank 122 is inserted into the cavity 110, the first pin end 128 may be disposed adjacent the second collar end 106, and the second pin end 130 may be disposed adjacent the first collar end 104. In various non-limiting embodiments, the pin 120 may include a head portion 136 configured to prevent the pin 120 from passing into a hole in a structure more than a predetermined distance. In various other non-limiting embodiments, the pin 120 may not include a head portion (not shown).

[0021] In various embodiments, first pin end 128 may include a tension region 124 configured to be engaged by a fixture (e.g., fixture 248 as shown in FIGS. 2-3). Tension region 124 may include at least one of a generally smooth region, an annular shoulder, a groove, and an aperture, and / or may include one or more additional features configured to be engaged by a fixture. For example, in certain non-limiting embodiments, tension region 124 may include a groove 132 that may be engaged by a fixture.

[0022] In various embodiments, the shank 122 may define a longitudinal axis of the pin 120. The shank 122 may be configured to engage the fastening collar 102 to secure the shank 122 to the fastening collar 102. When engaged, the longitudinal axis of the pin 120 and the longitudinal axis of the fastening collar 102 may be substantially aligned along the longitudinal axis A1 of the multi-piece fastener 100.

[0023] The cavity 110 of the fastening collar 102 may be configured to at least partially receive the shank 122 of the pin 120 therein. For example, the cavity 110 may have a shape suitable for receiving the shank 122 of the pin 120, such as, for example, a generally cylindrical shape. During and / or after introduction of the shank 122 into the cavity 110, the elongated portion 108, including at least a portion of the inner collar surface 116a, may at least partially deform to conform to the shank 122 in response to forceful contact between the outer collar surface 116b of the elongated portion 108 and the fastener, as described below with respect to FIGS. 2-3 . Deformation of the elongated portion 108 may secure the fastening collar 102 to the shank 122. In various non-limiting embodiments, the pin 120 may include a breakneck groove (not shown) or other feature configured to break during installation of the multi-piece fastener 100, and the tension region 124 may separate after installation. In various non-limiting embodiments, the diameter of the shank 122 ranges from 0.06 inches to 4 inches. The shank 122 may include at least one of a generally smooth region, an annular shoulder, a groove, and threads that can engage the inner collar surface 116a of the fastening collar 102.

[0024] The multi-piece fastener 100 includes a coating 114 on the outer collar surface 116b. The coating 114 includes a film-forming resin and a metallic pigment. As used herein, one embodiment of a "film-forming resin" is a resin that forms a self-supporting continuous film upon removal of any diluent or carrier during physical drying and / or curing at ambient or elevated temperatures. As used herein, various embodiments of a "film-forming resin" include resins that are self-crosslinking, resins that crosslink by reaction with a crosslinking agent, resins that form a solid film upon solvent evaporation, mixtures of one or more thereof, etc. As used herein, in certain embodiments, "film-forming resin" may refer collectively to both the resin and its crosslinker.

[0025] In certain embodiments, the film-forming resin may comprise a thermosetting film-forming resin and / or a thermoplastic film-forming resin. As used herein, the term "thermosetting" refers to a resin that is irreversibly "cured" upon curing or crosslinking, where the polymer chains of the polymeric components are bonded together by covalent bonds, which are often induced, for example, by heat or radiation. In various non-limiting embodiments, the curing or crosslinking reaction may be carried out under ambient conditions. Various embodiments of the thermosetting coating composition may include a crosslinker that may be selected from, for example, aminoplasts, polyisocyanates (including blocked isocyanates), polyepoxides, beta-hydroxyalkylamides, polyacids, anhydrides, organometallic acid-functional materials, polyamines, polyamides, and mixtures of any of the foregoing. Once cured or crosslinked, the thermosetting film-forming resin may not melt upon application of heat and may be insoluble in conventional solvents. As used herein, the term "thermoplastic" refers to a resin that includes polymeric components that are not bonded by covalent bonds, can undergo liquid flow upon heating, and is soluble in certain conventional solvents.

[0026] The film-forming resin may include functional groups reactive with a crosslinker. The film-forming resin in the coatings described herein may be selected from any of a variety of polymers known in the art, including, but not limited to, acrylic polymers, epoxies, polyester polymers, polyurethane polymers, polyamide polymers, polyether polymers, polysiloxane polymers, copolymers of one or more thereof, and mixtures of one or more thereof. The functional groups on the film-forming resin may be selected from, but not limited to, carboxylic acid groups, amine groups, epoxide groups, hydroxyl groups, thiol groups, carbamate groups, amide groups, urea groups, isocyanate groups (including blocked isocyanate groups), mercaptan groups, or one or more combinations thereof.

[0027] The metallic pigments included in the coating 114 may include one or more metals and / or metal alloys. The metallic pigments may increase the opacity of the coating 114 and / or may not increase the coefficient of friction of the outer color surface 116b on which the coating 114 is disposed. Additionally, the metallic pigments may decrease the coefficient of friction of the outer color surface 116b. The coating 114 may have an opacity of at least 25%, e.g., at least 30%, at least 40%, at least 50%, at least 75%, at least 90%, at least 95%, or at least 99%. The opacity of the coating may increase the ease with which the coating 114 can be viewed on the outer color surface 116b by an operator and / or machine.

[0028] The lightness of a coating is measured and quantified at various angles and is calculated using the International Commission on Illumination (CIE) L * Use the values ​​to determine the CIELAB L * values ​​may be reported using CIE L * a * b * The CIELAB color values ​​may be measured using an integrating sphere spectrophotometer under D65 illumination and a 10° viewing angle. For example, the CIELAB L color values ​​of at least a region of the outer color surface 116b of the fastening collar 102 may be measured using an integrating sphere spectrophotometer under D65 illumination and a 10° viewing angle. * The value may be 10 or less when measured with an integrating sphere spectrophotometer under D65 illumination, at a 10° viewing angle, and with the specular reflection component removed, such as 7 or less, 5 or less, or 4 or less, all measured with an integrating sphere spectrophotometer under D65 illumination, at a 10° viewing angle, and with the specular reflection component removed.

[0029] In various non-limiting embodiments, coating 114 includes aluminum, an aluminum alloy, or a combination thereof. For example, coating 114 may include aluminum in a range of 0.1% to 30% by weight based on the total weight of coating 114, such as 1% to 20% by weight, 1% to 15% by weight, or 2% to 15% by weight, all based on the total weight of coating 114.

[0030] To reduce the coefficient of friction of the outer collar surface 116b, the coating may be free of pigments or other components that increase the coefficient of friction. For example, the coating 114 may include 0.01% or less by weight of metal oxides, based on the total weight of the coating 114. In various non-limiting embodiments, the coating 114 may include 0.01% or less by weight of titanium dioxide, based on the total weight of the coating 114.

[0031] Coating 114 may include various other components and / or additives. For example, in certain embodiments, coating 114 may include at least one of a fluorescent dye and a fluorescent pigment. For example, the fluorescent dye may include an ultraviolet (UV) fluorescent dye. In various non-limiting embodiments, coating 114 may be readily visible by exciting the fluorescent dye and / or fluorescent pigment with a corresponding light source (e.g., a UV light source for a UV fluorescent dye). Thus, coating 114 may be visible under ambient light and / or when excited by a suitable light source, thereby providing a visible indication of the installation of multi-piece fastener 100 in a variety of lighting conditions.

[0032] The coating 114 may be formed from a coating composition that is applied to the fastening collar 102, for example, by at least one of brushing, spray coating, spin coating, dip coating, roll coating, flow coating, and film coating. In various non-limiting embodiments, the coating 114 may be a solvent-based coating or a water-based coating. In certain embodiments, the coating composition may be applied to the fastening collar 102 to achieve various predetermined shapes of the area covered by the coating 114. In various embodiments, the coating composition may be applied to the fastening collar 102 and then cured and / or physically dried (e.g., to remove any diluents or carriers).

[0033] As used herein, the terms "cured" and "to cure" refer to the chemical crosslinking of components in a coating composition that is applied as a coating layer onto a substrate. Thus, the terms "cured" and "to cure" do not encompass solely the physical drying of a coating composition through solvent or carrier evaporation. In this regard, as used herein, the term "cured" refers to a state of a coating layer in which the components of the coating composition that form the layer have chemically reacted to form new covalent bonds in the coating layer (e.g., new covalent bonds formed between the binder resin and the hardener).

[0034] The coating 114 may cover at least a portion of the fastening collar 102, and in some non-limiting embodiments, the coating 114 covers the entire outer collar surface 116b of the fastening collar 102. In various non-limiting embodiments, the coating 114 is not present on the flange 118. In certain non-limiting embodiments, the coating 114 is in the form of a strip, as illustrated in the non-limiting example shown in FIG.

[0035] The multi-piece fastener 100 may include a lubricating layer 140 intermediate the outer collar surface 116b and the coating 114. The lubricating layer 140 may cover at least a portion of the fastening collar 102, and in some non-limiting embodiments, the lubricating layer 140 covers the entire outer collar surface 116b of the fastening collar 102. The lubricating layer 140 may reduce the coefficient of friction on the outer collar surface 116b and facilitate movement of the anvil 254 while forcibly contacting the outer collar surface 116b. The lubricating layer 140 may prevent the formation of a bond between the coating 114 and the fastening collar 102, such that the coating 114 may be at least partially removed during installation of the multi-piece fastener 100. The lubricating layer 140 may include wax, tungsten disulfide, or other compounds suitable for reducing the coefficient of friction on the outer collar surface 116b.

[0036] In various non-limiting embodiments, the multi-piece fastener 100 may include a corrosion-resistant layer 142 intermediate the outer collar surface 116b and the coating 114. The corrosion-resistant layer 142 may cover at least a portion of the fastening collar 102, and in some non-limiting embodiments, the lubricating layer 140 covers the entire outer collar surface 116b of the fastening collar 102. The corrosion-resistant layer 142 may be suitable for enhancing the corrosion resistance of the multi-piece fastener. For example, the corrosion-resistant layer 142 may include a zinc electroplating layer, a chemical coating layer (e.g., GEOMET® water-based chemical coating available from NOF Metal Coatings North America, Chardon, OH, USA), and / or other layers suitable for inhibiting corrosion.

[0037] The fastening collar 102 is configured to be deformed onto the shank 122 by forcing contact of the outer collar surface 116b of the fastening collar 102. Forcing contact of the outer collar surface 116b at least partially removes the coating 114 on the outer collar surface 116b, indicating successful installation of the multi-piece fastener 100. For example, an operator and / or machine may observe a change in the amount of coating 114 on the outer collar surface 116b after installation compared to the coating 114 on the outer collar surface 116b before installation. In various non-limiting embodiments, when the coating 114 is in the form of a strip, the coating 114 may be substantially or completely removed during installation of the multi-piece fastener 100, thereby indicating that the multi-piece fastener 100 has been properly installed.

[0038] Multi-piece fasteners according to the present disclosure may include at least one of a metal, a metal alloy, a composite material, or other suitable material. For example, in various embodiments, a multi-piece fastener according to the present disclosure (e.g., multi-piece fastener 100) may include at least one of aluminum, an aluminum alloy, titanium, a titanium alloy, nickel, a nickel alloy, iron, an iron alloy, and a carbon fiber composite material.

[0039] As shown in Figures 2-3, the multi-piece fastener 100 may be installed within a hole 246 in a structure 344. As shown, the hole 246 may extend through the structure 344 from a first side 358 to a second side 360. In various other non-limiting embodiments, the hole 246 may extend from the first side 358 but not entirely through the structure 344, thereby forming a blind hole and allowing the use of a multi-piece fastener according to the present disclosure configured as a blind fastener. In various embodiments, the hole 246 may include threads, while in other non-limiting embodiments, the hole 246 does not include threads.

[0040] The structure 344 may include, for example, at least one of a metal, a metal alloy, a polymer, wood, concrete, a composite material, or other suitable material. For example, in certain embodiments, the structure 344 may include at least one of aluminum, an aluminum alloy, titanium, a titanium alloy, nickel, a nickel alloy, iron, an iron alloy, and a carbon fiber composite material. In various embodiments, the structure 344 into which the multi-piece fastener 100 is incorporated includes aluminum and / or an aluminum alloy, such as 7075 aluminum alloy. With reference to the accompanying figures, in various non-limiting embodiments, the structure 344 may be configured as at least one of an aircraft component or structure, an automotive component or structure, a transportation component or structure, a building and construction component or structure, or other component or structure.

[0041] The structure 344 may include a single layer of material, or at least two (i.e., more than two) layers of material. For example, as illustrated in FIGS. 2-3 , the structure 344 may include a first layer of material 344a and a second layer of material 344b. The first layer of material 344a may be intermediate the second layer of material 344b and the fastening collar 102 when the fastening collar 102 is attached. In various non-limiting embodiments, the first layer of material 344a is adjacent to the fastening collar 102.

[0042] To facilitate alignment of the multi-piece fastener 100 and the hole 246, the size and / or shape of the first pin end 128 may be configured to easily enter and move through the hole 246. In various embodiments, the diameter of the head portion 136 may be larger than the diameter of the hole 246 to prevent the pin 120 from advancing further into the hole 246. In various non-limiting embodiments lacking a head portion 136, the diameter of the second pin end 130 may be sized and configured to be smaller than the diameter of the hole 246, thereby allowing the second pin end 130 to easily move into and through the hole 246.

[0043] 2, the first pin end 128 of the pin 120 was positioned to align with the second side 360 ​​of the hole 246 before being inserted through the hole 246. In various other non-limiting embodiments in which the multi-piece fastener 100 is configured as a blind fastener without a head portion 136, the second pin end 130 of the pin 120 may be positioned to align with the first side 358 of the hole 246 and inserted through the hole 246.

[0044] 2 , the fastening collar 102 is shown positioned over the first pin end 128, with the first pin end 128 inserted into and through the cavity 110 of the fastening collar 102. The first collar end 104 of the fastening collar 102 contacts the first layer of material 344a of the structure 344. In various non-limiting embodiments in which the pin 120 and fastening collar 102 are threaded, rotation of at least one of the fastening collar 102 and pin 120 may be required to insert the first pin end 128 into the cavity 110 of the fastening collar 102.

[0045] The fastening collar 102 may be forced into contact with the structure 344. The forced contact between the fastening collar 102 and the structure 344 may limit further axial movement of the fastening collar 102 relative to the pin 120 along the longitudinal axis of the multi-piece fastener 100.

[0046] 2, a multi-piece fastener attachment tool 248 is shown. The attachment tool 248 includes a housing 256, an anvil 254 positioned within the housing 256, and a collet 252 positioned within the housing 256. The anvil 254 may be configured to selectively forcibly contact at least a portion of the fastening collar 102 of the multi-piece fastener 100. The collet 252 includes a first collet end 252a adjacent the anvil 254, the first collet end 252a including jaws configured to forcibly contact at least a portion of the tension region 124 of the shank 122 of the multi-piece fastener 100.

[0047] 2 , the collet 252 of the fixture 248 engages the shank 122 of the pin 120 of the multi-piece fastener 100. The collet 252 may be configured to retract into the fixture 248, causing the collet 252 to forcefully contact the anvil 254 of the fixture 248. The collet 252 may then close around and forcefully contact, thereby engaging, the tension region 124 of the pin 120. Upon engagement, the collet 252 may apply an axial force to the tension region 124 of the pin 120, which may reduce the gap (if present) between the first and second material layers 344 a and 344 b of the structure 344 and create forceful contact between the fastening collar 102 and the structure 344.

[0048] The anvil 254 may at least partially deform the fastening collar 102 onto the shank 122 of the pin 120, thereby securing the fastening collar 102 to the shank 122. As the anvil 254 deforms the fastening collar 102, the coating 114 may be at least partially removed from the fastening collar 102. For example, with reference to FIG. 3 , contact between the tension region 124 and the collet 252 may cause the collet 252 to retract into the fixture 248, moving the pin 120 as the collet 252 retracts. As the collet 252 retracts, the anvil 254 forcibly contacts the fastening collar 102, including the outer collar surface 116 b and the coating 114. After a predetermined force is achieved, the elongated portion 108 may be at least partially deformed and the coating 114 may be at least partially removed from the outer collar surface 116 b in response to the forcible contact between the anvil 254 and the fastening collar 102. For example, the extended portion 108 may be at least partially crimped onto at least a portion of the shank 122. The at least partial removal of the coating 114 may be a visual indication to an operator and / or machine that the multi-piece fastener 100 has been properly installed. In various non-limiting embodiments, because the coating 114 includes metallic pigments, the force applied by the fixture 248 to deform the extended portion 108 may be reduced compared to the force applied by the fixture 248 to the fastening collar without the coating 114. For example, the metallic pigments may act as a lubricant, thereby reducing the coefficient of friction on the outer collar surface 116b and facilitating movement of the anvil 254 while forcibly contacting the outer collar surface 116b.

[0049] As shown in FIGURE 3, after installing the multi-piece fastener 100 in the structure 344, the fastening collar 102 and the head portion 136 of the pin 120 may apply a clamping force to the structure 344, thereby securing the two-piece fastener 100 to at least a portion of the structure 344. In this manner, for example, the first material layer 344a and the second material layer 344b of the structure 344 are secured together. The coating 114 has been removed from the outer collar surface 116b in FIGURE 3 to visually indicate proper installation of the multi-piece fastener 100 (after the fixture 248 has been removed).

[0050] In various non-limiting embodiments, the fastener may be a tensioning tool or a compression tool. For example, as known in the art, a compression tool may simultaneously apply a compressive force to the fastening collar 102 and the second pin end 130 of the pin 120. The compression force may deform the fastening collar 102 onto the shank 122 of the pin 120, thereby securing the fastening collar 102 onto the shank 122.

[0051] Referring to FIG. 4 , in various non-limiting embodiments, a method for fastening a structure may be used to install a multi-piece fastener in accordance with the present invention. In step 402, a first pin end 128 of a multi-piece fastener 100 is inserted into a hole 246 in a structure 344. In step 404, a tension region 124 of a pin 120 of the multi-piece fastener 100 may be forced into contact with the jaws of a collet 252 of a fixture 248. In step 406, an outer collar surface 116 b of a fastening collar 102 is forced into contact with an anvil 254 of the fixture 248, and the tension region 124 moves distally from the fastening collar 102, utilizing the collet 252 of the fastening collar fixture 248. This deforms the fastening collar 102 onto the shank 122 of the pin 120 and at least partially removes the coating 114 on the outer collar surface 116 b, thereby indicating proper installation of the multi-piece fastener 100. In various non-limiting embodiments, at least 90% of the total visible surface area of ​​the coating 114 originally present on the outer collar surface 116b is removed in step 406 during installation of the multi-piece fastener 100, such as at least 95%, or at least 99%, of the total visible surface area of ​​the coating 114 originally present on the outer collar surface 116b, thereby visually indicating proper installation. Visible surface area refers to the surface area of ​​the coating 114 that is visible by an operator during installation of the multi-piece fastener 100.

[0052] Various aspects of non-limiting embodiments of the invention according to this disclosure include, but are not limited to, the aspects listed in the following numbered clauses:

[0053] Clause 1. A multi-piece fastener comprising: A fastening collar, an inner collar surface defining a collar cavity; an outer color surface; a coating on the outer color surface, the coating comprising a film-forming resin and a metallic pigment; a fastening collar having a lubricating layer intermediate the coating and the outer collar surface; a pin configured to be at least partially received by the collar cavity, a first pin end; a second pin end; and a pin including a shank extending intermediate the first pin end and the second pin end; a multi-piece fastener, wherein the fastening collar is configured to be deformed onto the shank by forcing the outer collar surface of the fastening collar into contact, the forcing the outer collar surface into contact at least partially removing the coating on the outer collar surface and indicating installation of the multi-piece fastener.

[0054] Clause 2. The multi-piece fastener of clause 1, wherein the metallic pigment comprises aluminum, an aluminum alloy, or a combination thereof.

[0055] Clause 3. The multi-piece fastener of any of clauses 1-2, wherein the coating comprises 0.01% by weight or less of titanium dioxide, based on the total weight of the coating.

[0056] Clause 4. The multi-piece fastener of any of clauses 1-3, wherein the coating comprises 0.01 wt. % or less of metal oxides, based on the total weight of the coating.

[0057] Clause 5. The multi-piece fastener of any of clauses 1-4, wherein the coating further comprises at least one of a fluorescent dye and a fluorescent pigment.

[0058] Clause 6. CIELAB L of at least a region of said outer collar surface of said fastening collar * 6. The multi-piece fastener of any of clauses 1-5, wherein the value is 10 or less when measured with an integrating sphere spectrophotometer under D65 illumination, at a 10° viewing angle, and with the specular component excluded.

[0059] Clause 7. The multi-piece fastener of any of clauses 1-6, further comprising a corrosion-resistant layer intermediate the coating and the outer collar surface.

[0060] Clause 8. The multi-piece fastener of any of clauses 1-7, wherein the fastening collar further comprises a flange, and the coating is not present on the flange.

[0061] Clause 9. The multi-piece fastener of any of clauses 1-8, wherein the coating is in the form of a strip.

[0062] Clause 10. The multi-piece fastener of any of clauses 1-9, wherein the coating has an opacity of at least 25%.

[0063] Clause 11. A multi-piece fastener according to any of clauses 1 to 10, wherein the coating does not increase the coefficient of friction of the outer collar surface of the fastening collar.

[0064] Clause 12. The multi-piece fastener of any of clauses 1-11, wherein the shank comprises at least one of a generally smooth region, an annular shoulder, a groove, and a threaded region.

[0065] Clause 13. The multi-piece fastener of any of clauses 1-12, wherein the multi-piece fastener is configured to be installed into a hole in a structure, the structure being at least one of an aircraft part or component, an automotive part or component, a transportation part or component, and a building and construction part or component.

[0066] Clause 14. The multi-piece fastener of any of clauses 1-13, wherein the shank diameter is in the range of 0.06 inches to 4 inches.

[0067] Clause 15. The multi-piece fastener of any of clauses 1-14, wherein the multi-piece fastener comprises at least one of a metal and a metal alloy.

[0068] Clause 16. A rock bolt comprising the multi-piece fastener according to any one of clauses 1 to 15.

[0069] Article 17. Methods for concluding Inserting a first pin end of a multi-piece fastener into a hole in a structure, the multi-piece fastener comprising: A fastening collar, an inner collar surface defining a collar cavity; an outer color surface; a coating on the outer color surface, the coating comprising a film-forming resin and a metallic pigment; a fastening collar having a lubricating layer intermediate the coating and the outer collar surface; a pin configured to be at least partially received by the collar cavity, a first pin end; a second pin end; and inserting a pin having a shank extending intermediate the first pin end and the second pin end; inserting the pin at least partially into the collar cavity; and forcing the outer collar surface of the fastening collar into contact with an anvil of a fastening collar installation tool, thereby deforming the fastening collar onto the shank of the pin, wherein forcing the outer collar surface into contact at least partially removes the coating on the outer collar surface, indicating installation of the multi-piece fastener.

[0070] Clause 18. The method of claim 1, wherein the first pin end includes a tension region; 18. The method of clause 17, further comprising forcing the tension region into contact with jaws of a collet of the fastening collar fixture.

[0071] Clause 19. The method of any one of clauses 17 to 18, wherein the metal pigment comprises aluminum.

[0072] Clause 20. The method of any of clauses 17-19, wherein forcing the outer collar surface into contact removes at least 90% of the total visible surface area of ​​the coating from the outer collar surface of the fastening collar.

[0073] As used herein, unless otherwise indicated, all numerical parameters should be understood in all instances to be prefaced and modified by the term "about," given the inherent variability characteristic of the underlying measurement technique used to determine the numerical value of that parameter. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter set forth herein should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0074] Additionally, any numerical range recited herein includes all subranges subsumed within the recited range. For example, a range of "1 to 10" includes all subranges between (and including) the recited minimum of 1 and the recited maximum of 10, i.e., all subranges having a minimum of 1 or greater and a maximum of 10 or less. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein, and any minimum numerical limitation recited herein is intended to include all higher numerical limitations subsumed therein. Accordingly, applicants reserve the right to amend this specification, including the claims, to expressly recite any subranges subsumed within the expressly recited range. All such ranges are inherently described herein.

[0075] The grammatical articles "a," "an," and "the," as used herein, unless otherwise indicated, are intended to include "at least one" or "one or more," even if "at least one" or "one or more" is expressly used in a specific instance. Thus, the above grammatical articles are used herein to refer to one or more than one (i.e., "at least one") of the particular identified element. Furthermore, unless the context of usage requires otherwise, the use of a singular noun includes the plural and the use of a plural noun includes the singular.

[0076] Those skilled in the art will recognize that the fasteners, structures, operations / actions, and objects described herein, as well as their accompanying descriptions, are used as examples for conceptual clarity and that various structural modifications are contemplated. Thus, as used herein, the specific examples / embodiments described and the accompanying discussion are intended to be representative of their more general classes. In general, the use of any particular example is intended to be representative of its classification, and the absence of a particular component, device, apparatus, operation / action, or object should not be construed as limiting. While this disclosure provides descriptions of various specific aspects for the purpose of illustrating various aspects of the disclosure and / or its potential applications, it is understood that variations and modifications will occur to those skilled in the art. Accordingly, it should be understood that the invention(s) described herein are at least as broad as they are claimed, and not more narrowly defined by the specific exemplary aspects provided herein. [Explanation of symbols]

[0077] 100 Multi-Piece Fasteners 102 Fastening collar 104 first collar end 106 Second collar end 108 parts 110 Cavity 114 Coating 116a Inner color surface 116b outer color surface 118 flange 120 pins 122 Shank 124 Tensile Region 128 first pin end 130 second pin end 132 Groove 136 Head part 140 Lubricating layer 142 Corrosion-resistant layer 246 holes 248 Mounting fixture 252 Colette 252a first collet end 254 Anvil 256 Housing 344 Structure 344a First material layer 344b Second material layer 358 First Aspect 360 Second Aspect 402 Step 404 Step 406 Steps A1 Longitudinal axis

Claims

1. A multi-piece fastener comprising: A fastening collar, an inner collar surface defining a collar cavity; an outer color surface; a coating on the outer color surface, the coating comprising a film-forming resin and a metallic pigment; a fastening collar having a lubricating layer intermediate the coating and the outer collar surface; a pin configured to be at least partially received by the collar cavity, a first pin end; a second pin end; and a pin including a shank extending intermediate the first pin end and the second pin end; a multi-piece fastener, wherein the fastening collar is configured to be deformed onto the shank by forcing the outer collar surface of the fastening collar into contact, the forcing the outer collar surface into contact at least partially removing the coating on the outer collar surface and indicating installation of the multi-piece fastener.

2. The multi-piece fastener of claim 1 , wherein the metallic pigment comprises aluminum, an aluminum alloy, or a combination thereof.

3. 10. The multi-piece fastener of claim 1, wherein the coating comprises no more than 0.01% by weight of titanium dioxide, based on the total weight of the coating.

4. 10. The multi-piece fastener of claim 1, wherein the coating comprises no more than 0.01 weight percent metal oxides, based on the total weight of the coating.

5. The multi-piece fastener of claim 1 , wherein the coating further comprises at least one of a fluorescent dye and a fluorescent pigment.

6. 10. The multi-piece fastener of claim 1, wherein at least a region of said outer color surface of said fastening collar has a CIELAB L* value of 10 or less when measured with an integrating sphere spectrophotometer under D65 illumination, at a 10° viewing angle, and with the specular component excluded.

7. 10. The multi-piece fastener of claim 1, further comprising a corrosion resistant layer intermediate said coating and said outer collar surface.

8. 10. The multi-piece fastener of claim 1, wherein the fastening collar further comprises a flange, and the coating is absent from the flange.

9. 10. The multi-piece fastener of claim 1, wherein the coating is in the form of a strip.

10. 10. The multi-piece fastener of claim 1, wherein the coating has an opacity of at least 25%.

11. 10. The multi-piece fastener of claim 1, wherein the coating does not increase the coefficient of friction of the outer collar surface of the fastening collar.

12. The multi-piece fastener of claim 1 , wherein the shank comprises at least one of an annular shoulder, a groove, and a threaded region.

13. 10. The multi-piece fastener of claim 1, wherein the multi-piece fastener is configured to be installed into an aperture in a structure, the structure being at least one of an aircraft part or component, an automotive part or component, a transportation part or component, and a building and construction part or component.

14. 10. The multi-piece fastener of claim 1, wherein the shank diameter ranges from 0.06 inches (1.524 mm) to 4 inches (101.6 mm).

15. The multi-piece fastener of claim 1 , wherein the multi-piece fastener comprises at least one of a metal and a metal alloy.

16. A method for fastening, comprising: Inserting a first pin end of a multi-piece fastener into a hole in a structure, the multi-piece fastener comprising: A fastening collar, an inner collar surface defining a collar cavity; an outer color surface; a coating on the outer color surface, the coating comprising a film-forming resin and a metallic pigment; a fastening collar comprising a lubricating layer intermediate said coating and said outer collar surface; a pin configured to be at least partially received by the collar cavity, a first pin end; a second pin end; and inserting a pin having a shank extending intermediate the first pin end and the second pin end; inserting the pin at least partially into the collar cavity; and deforming the fastening collar onto the shank of the pin by forcing the outer collar surface of the fastening collar into contact with an anvil of a fastening collar installation tool, wherein forcing the outer collar surface into contact at least partially removes the coating on the outer collar surface and indicates installation of the multi-piece fastener.

17. the first pin end including a tension region, and the method further comprising:

17. The method of claim 16, further comprising forcing the tension region into contact with jaws of a collet of the fastening collar fixture.

18. The method of claim 16 , wherein the metallic pigment comprises aluminum.

19. 17. The method of claim 16, wherein forcing the outer collar surface into contact removes at least 90% of the total visible surface area of ​​the coating from the outer collar surface of the fastening collar.

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