Multi-piece fasteners, multi-piece fastener installation apparatus, and methods of fastening

Abstract

To provide multi-piece fasteners, multi-piece fastener installation apparatus, and methods of fastening.SOLUTION: A multi-piece fastener includes a fastening collar and a pin. The fastening collar includes a first collar end and a second collar end. A collar cavity extends from the first collar end to the second collar end. The pin is configured to be at least partially received in the collar cavity. The pin includes a first pin end, a second pin end, and a shank extending between the first pin end and the second pin end. The shank comprises a plurality of structural features. A first feature among the plurality of structural features has a first configuration, and a second feature among the plurality of structural features has a second configuration. The first configuration and the second configuration are different from each other.SELECTED DRAWING: Figure 3A

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to multi-piece fasteners, multi-piece fastener installation devices, and fastening methods. [Background technology]

[0002] Vehicle frames, storage racks, solar panel substructures, aircraft parts, and other structures may include numerous mechanical fasteners. For example, structural fasteners may be installed in holes in structural components to secure the parts together. Properly installing structural fasteners in the holes can be difficult. Summary of the Invention

[0003] 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 a first collar end and a second collar end. A collar cavity extends from the first collar end to the second collar end. 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. The shank includes a plurality of structural features. A first feature of the plurality of structural features has a first configuration, and a second feature of the plurality of structural features has a second configuration. The first configuration and the second configuration are different.

[0004] According to another non-limiting aspect of the present disclosure, a method for fastening is provided. The method includes inserting a second pin end of a multi-piece fastener into a hole in a structure and forcing a tension region of the pin of the multi-piece fastener into contact with an installation device. The method includes measuring a load applied to the multi-piece fastener by the installation device and a stroke length of a collet during installation of the multi-piece fastener using the installation device. A fastening collar of the multi-piece fastener is forcibly contacted with an anvil of the installation device and the tension region is moved distally from the fastening collar, thereby deforming the fastening collar to conform to a shank of the pin and securing at least a portion of the multi-piece fastener to the structure. The method includes utilizing the measured load and the measured stroke length to determine whether the collar has deformed to conform to a first feature of the shank of the multi-piece fastener during installation of the multi-piece fastener using the installation device.

[0005] According to yet another non-limiting aspect of the present disclosure, a multi-piece fastener installation apparatus is provided. The multi-piece fastener installation apparatus includes a housing defining a housing cavity, an anvil within the housing cavity, a collet within the housing cavity, and a programmable hardware device. The anvil is configured to forcibly contact at least a portion of a collar of the multi-piece fastener. The collet includes a first collet end adjacent to the anvil. The first collet end is configured to forcibly contact at least a portion of a tension region of a shank of the multi-piece fastener. The programmable hardware device is configured to measure a load applied by the collet to the multi-piece fastener during installation of the multi-piece fastener using the installation apparatus, and to measure a stroke length of the collet while applying the load during installation of the multi-piece fastener using the installation apparatus. The programmable hardware device is configured to utilize the measured load and the measured stroke length to determine whether the collar of the multi-piece fastener has deformed to conform to a first feature of a plurality of structural features on the shank of the multi-piece fastener during installation of the multi-piece fastener using the installation apparatus.

[0006] It will be understood that the invention disclosed and described herein is not limited to the aspects summarized in this Summary. The reader will understand these and other details upon consideration of the following detailed description of various non-limiting and non-exhaustive aspects hereof. [Brief explanation of the drawings]

[0007] The features and advantages of the examples presented herein, and the manner in which they are achieved, will become more apparent and the examples will be better understood by referring to the following description in conjunction with the accompanying drawings.

[0008] [Figure 1A] FIG. 1A is a partial cross-sectional side view of a non-limiting example of an acceptable installation of a multi-piece fastener.

[0009] [Figure 1B] FIG. 1B is a partial cross-sectional side view of a non-limiting example of an unacceptable installation of a multi-piece fastener.

[0010] [Figure 2] FIG. 2 is a partial cross-sectional side view of a non-limiting embodiment of a multi-piece fastener according to the present disclosure.

[0011] [Figure 3A] FIG. 3A is a partial cross-sectional side view of a non-limiting embodiment of a multi-piece fastener and multi-piece fastener installation device according to the present disclosure shown in a hole in a structure and in a first configuration.

[0012] [Figure 3B] FIG. 3B is a partial cross-sectional side view of the multi-piece fastener and multi-piece fastener installation device of FIG. 3A shown in a hole in a structure and in a second configuration.

[0013] [Figure 3C]FIG. 3C is a partial cross-sectional side view of the multi-piece fastener and multi-piece fastener installation device of FIG. 3A shown in a hole in a structure and in a third configuration.

[0014] [Figure 4A] FIG. 4A is a plot of measured stroke length versus measured load for the installation apparatus of FIG. 3A when moving from the first configuration shown in FIG. 3A to the second configuration shown in FIG. 3B.

[0015] [Figure 4B] FIG. 4B is a plot of measured stroke length versus measured load for the installation apparatus of FIG. 3A when moving from the second configuration shown in FIG. 3B to the third configuration shown in FIG. 3C.

[0016] [Figure 5] FIG. 5 is a plot of measured stroke length versus measured load during installation of first and second non-limiting embodiments of a multi-piece fastener according to the present disclosure.

[0017] [Figure 6] FIG. 6 is a flow chart illustrating a non-limiting embodiment of a method for fastening according to the present disclosure.

[0018] 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 way. DETAILED DESCRIPTION OF THE INVENTION

[0019] Various examples are described and illustrated herein to provide a thorough understanding of the structure, function, and use of the disclosed fastening collars, multi-piece fastening systems, and fastening methods. The various examples 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 examples disclosed herein. Rather, the present invention is defined solely by the claims. Features and characteristics illustrated and / or described in connection with various examples may be combined with features and characteristics of other examples. 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. Furthermore, applicants reserve the right to amend the claims to affirmatively 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.

[0020] Any reference herein to "various embodiments," "some embodiments," "one embodiment," "an 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," "in one embodiment," "in one 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 a 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.

[0021] As used herein, "intermediate" means that the referenced component is disposed between, but not necessarily in contact with, two other components. Thus, unless otherwise stated herein, a component "intermediate" between a first component and a second component may or may not be adjacent to, or in contact with, the first and / or second components, and additional components may be disposed between the intermediate component and the first and / or second components.

[0022] For example, when a structural fastener, such as a rock bolt, is installed in a hole in a structure, the collar of the rock bolt is deformed (e.g., swaged) to fit a section of the fastener's pin. Depending on the user and / or installation tool, an undesirable fastener may be used in the installation, the collar may not be acceptably deformed (e.g., the distance along the collar axis is too short or too long, and / or the degree of deformation at a particular point is too great or too small), the collar may be improperly aligned with the pin, or other defects may exist. For example, as shown in FIG. 1A , the fastening collar 102 of a rock bolt 100 a is shown partially deformed and the fastening collar 102 is shown deformed to fit all of the grooves on the shank 122 of the pin 120 of the rock bolt 100 a. The configuration shown in FIG. 1A may be considered an acceptable installation for some applications. In contrast, in the configuration shown in Figure 1B, the fastening collar 102 of the bolt 100b is partially deformed, and the fastening collar 102 has not deformed to fit all of the grooves 134 on the shank 122 of the pin 120 of the lock bolt 100. The configuration shown in Figure 1B may be considered an unacceptable installation for some applications because the fastening collar 102 has not deformed to fit the minimum desired number of grooves 134.

[0023] To ensure that a rock bolt is properly installed, a crimp gauge may be used to verify the installation of the rock bolt. A crimp gauge typically has two distinct sides: a touch-go side that includes a first recess having a first size configured to receive a collar, and a touch-no-go side that includes a second recess having a first size configured to receive a collar. Using a crimp gauge to verify acceptable installation of a rock bolt requires an additional post-installation step, which can be time-consuming and subjective. Furthermore, measuring the total stroke distance of the collet of a rock bolt installation tool or the maximum applied load during installation of the rock bolt may not accurately and efficiently detect whether the fastening collar is properly positioned relative to the pin (e.g., whether the fastening collar is crimped onto the desired portion of the pin).

[0024] Thus, the present disclosure provides multi-piece fasteners, multi-piece fastener installation devices, and methods of fastening that allow for efficient verification of acceptable installation of structural fasteners during an installation procedure, and which may not require the use of an additional installation verification step with a swage gauge. Because the additional fastener installation verification step may not be required, the installation devices and processes may increase the accuracy and / or overall efficiency of the manufacturing process.

[0025] For example, FIG. 2 illustrates a non-limiting embodiment of a multi-piece fastener 200 according to the present disclosure. The multi-piece fastener 200 can be configured to be installed in a hole in a structure (e.g., as shown in FIGS. 3A-3C). The multi-piece fastener 200 may comprise at least two components, such as a fastening collar 202 and a pin 220 as shown in FIG. 2, or in some non-limiting embodiments, at least three components (not shown). In various non-limiting embodiments, the multi-piece fastener 200 may comprise a two-piece assembly including the fastening collar 202 and the pin 220. In some embodiments, the multi-piece fastener 200 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.

[0026] The fastening collar 202 may include a first collar end 204, a second collar end 206, a longitudinal portion 208 disposed intermediate the first collar end 204 and the second collar end 206, and a cavity 210 extending through the longitudinal portion 208 from the first collar end 204 to the second collar end 206. The longitudinal portion 208 may define a longitudinal axis of the fastening collar 202. A surface 216 of the longitudinal portion 208 adjacent the cavity 210 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 202 may be generally cylindrical.

[0027] In various non-limiting embodiments, the fastening collar 202 may include a flange 218. The fastening collar 202 may be configured to engage and / or be received by an anvil of an installation tool, while the flange diameter of the flange 218 may prevent the fastening collar 202 from penetrating a hole in a structure beyond a predetermined distance.

[0028] The pin 220 may include a first pin end 228, a second pin end 230, and a shank 222. The shank 222 may have a shape suitable for receipt by the cavity 210 of the fastening collar 202, such as, for example, a generally cylindrical shape. The shank 222 may extend intermediate the first pin end 228 and the second pin end 230 and may be dimensioned to be at least partially disposed within the cavity 210. When the shank 222 is inserted into the cavity 210, the first pin end 228 may be disposed adjacent the second sleeve end 206, and the second pin end 230 may be disposed adjacent the first collar end 204. In various non-limiting embodiments, the pin 220 may include a head portion 236 configured to prevent the pin 220 from moving through a hole in a structure beyond a predetermined distance. In various other non-limiting embodiments, the pin 220 may not include a head portion (not shown).

[0029] The first pin end 228 may include a tension region 224 configured to be engaged by (e.g., an installation tool 348, as shown in FIGS. 3A-3C and described below). The tension region 224 may have an axial length and, in various non-limiting embodiments, may not include a taper. In other non-limiting embodiments, the tension region 224 may include a taper or reverse taper. For example, the diameter of the tension region 224 may decrease along the tension region 224, moving away from the head 230 along the longitudinal axis of the pin 220. In certain other non-limiting embodiments, the tension region 224 may include a reverse taper, where the diameter of the tension region 224 increases along the tension region 224, moving away from the head 230 along the longitudinal axis of the pin 220. In various embodiments, the tension region 224 may be generally conical.

[0030] The tension region 224 may include at least one of a generally smooth region, an annular shoulder, a groove, and a hole, and / or may include another feature configured to be engaged by an installation tool (e.g., installation tool 348 as shown in FIGS. 3A-3C and described below). For example, in a particular non-limiting embodiment, as shown in FIG. 2, the tension region 224 may include a groove 232 that may be engaged by an installation tool.

[0031] The shank 222 can define a longitudinal axis of the pin 220. The shank 222 can be configured to engage with the fastening collar 202 to secure the shank 222 to the fastening collar 202. When engaged, the longitudinal axis A1 of the pin 220 and the longitudinal axis of the collar 202 can be substantially aligned along the longitudinal axis A1 of the multi-piece fastener 100.

[0032] The cavity 210 of the fastening collar 202 can be configured to at least partially receive the shank 222 of the pin 220 therein. For example, the cavity 210 can have a shape suitable for receiving the shank 222 of the pin 220, such as, for example, being generally cylindrical. During and / or after introduction of the shank 222 into the cavity 210, the longitudinal portion 208, including at least a portion of the surface 216, can deform at least partially to conform to the shank 222 in response to forcible contact between the longitudinal portion 208 and an installation tool, as described below. Deformation of the longitudinal portion 208 can secure the fastening collar 202 to the shank 222. In various non-limiting embodiments, the pin 220 can include a breakneck groove 240 or other feature configured to break during installation of the multi-piece fastener 200, and the tension region 224 can peel off after installation. In various non-limiting embodiments, the major diameter φ1 of the shank 222 ranges from 0.06 inches to 4 inches (0.1524 cm to 10.16 cm).

[0033] The shank 222 includes a structural feature 234, such as, for example, one or more annular shoulders, one or more grooves, one or more threads, and combinations thereof. The structural feature 234 can engage with the surface 216 of the fastening collar 202. The structural feature 234 can be an external structure on one or more regions of the shank 222. In various non-limiting embodiments, all or a region of the shank 222 includes a groove. For example, as shown in FIG. 2, the structural feature 234 is a groove. In various non-limiting embodiments, all or a portion of the shank 222 includes an annular shoulder (not shown). In various non-limiting embodiments, all or a portion of the shank 222 includes a thread (not shown). In certain non-limiting embodiments, all or a portion of the shank 222 includes one or more grooves and one or more threads.

[0034] 2 , a first feature 234a of the plurality of structural features 234 on the shank 222 may have a first configuration, and a second feature 234b of the plurality of structural features 234 may have a second configuration, where the first configuration and the second configuration are different. The first and second configurations are configured to allow for detection of the difference between the first and second configurations during installation of the fastener (e.g., deformation of the fastening collar 202 onto the pin 220). For example, during installation of the multi-piece fastener 200, measuring the load applied to the fastening collar 202 during deformation and the stroke distance during application of the load can allow for detection of the first and second configurations, thereby confirming that the fastening collar 202 has been swaged to its respective structural features 234a, 234b.

[0035] In various non-limiting multi-piece fastener embodiments in which the plurality of structural features 234 comprise grooves, the first feature 234a can be a first groove and the second feature 234b can be a second groove, and at least one dimension of the first groove and the second groove can differ. For example, the at least one dimension of the first groove and the second groove can include a groove pattern, a groove depth, or another dimension of the groove.

[0036] In various non-limiting multi-piece fastener embodiments in which the plurality of structural features 234 include annular shoulders, the first feature 234a can be a first annular shoulder and the second feature 234b can be a second annular shoulder, and at least one dimension of the first annular shoulder and the second annular shoulder can differ.

[0037] In various non-limiting multi-piece fastener embodiments in which the plurality of structural features 234 include threads, the first feature 234a can be a first thread and the second feature 234b can be a second thread, and at least one dimension of the first thread and the second thread can differ. For example, the at least one dimension of the first thread and the second thread can comprise a thread depth, an inner diameter, an outer diameter, or a thread pitch.

[0038] Multi-piece fastening systems 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., fastener 200) 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] 3A-3C, the multi-piece fastener 200 can be installed in a hole 346 in a structure 344. As shown, the hole 346 can extend completely through the structure 344 from the first side 368 to the second side 360. In various other non-limiting embodiments, the hole 346 can extend from the first side 368 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 346 can include threads, while in other non-limiting embodiments, the hole 346 does not include threads.

[0040] The structure 344 may include, for example, at least one of a metal, a metal alloy, 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 non-limiting embodiments, the structure 344 into which the multi-piece fastening system 200 is incorporated includes aluminum and / or an aluminum alloy, such as, for example, 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 aerospace part or structure, an automotive part or structure, a transportation part or structure, an architecture and construction part or structure, or other part or structure.

[0041] The structure 344 can include a single layer of material or at least two layers of material. For example, as shown in Figures 3A-3C, the structure 344 can include a first layer of material 344a and a second layer of material 344b. The first layer of material 344a can be intermediate the second layer of material 344b and the fastening collar 202 when the fastening collar 202 is installed. In various non-limiting embodiments, the first layer of material 344a is adjacent to the fastening collar 202.

[0042] To facilitate alignment of the multi-piece fastener 200 and the hole 346, the size and / or shape of the first pin end 228 can be configured to easily enter and move through the hole 346. In various embodiments, the diameter of the head portion 236 can be larger than the diameter of the hole 346 to prevent the pin 220 from advancing further into the hole 346. In various non-limiting embodiments lacking a head portion 236, the diameter of the second pin end 230 can be sized and configured to be smaller than the diameter of the hole 346, thereby allowing the second pin end 230 to easily move into and through the hole 346.

[0043] 3A , the first pin end 228 of the pin 220 is positioned to align with the second side 360 ​​of the hole 346 before being inserted therethrough. In various other non-limiting embodiments in which the multi-piece fastener 200 is configured as a blind fastener without a head portion 236, the second pin end 230 of the pin 220 is positioned to align with the first side 368 of the hole 346 and can be inserted therethrough.

[0044] 3A , the fastening collar 202 is positioned over the first pin end 228, and the first pin end 228 is shown inserted into and through the cavity 210 of the fastening collar 202. The second collar end 206 of the fastening collar 202 contacts the first layer 344a of the structure 344. In various non-limiting embodiments in which the pin 220 and the fastening collar 202 are threaded, rotation of at least one of the fastening collar 202 and the pin 220 may be required to insert the first pin end 228 into the cavity 210 of the fastening collar 202.

[0045] The fastening collar 202 may be forced into contact with the structure 344. The forced contact between the fastening collar 202 and the structure 344 can limit further axial movement of the fastening collar 202 relative to the pin 220 along the longitudinal axis A1.

[0046] 3A, a multi-piece fastener installation apparatus 348 is provided. The installation apparatus 348 includes a housing 356 defining a housing cavity 358, an anvil 354 positioned within the housing cavity 358, a collet 352 positioned within the housing cavity 358, and a programmable hardware device (PHD) 370. The anvil 354 can be configured to selectively contact at least a portion of the fastener collar 202 of the multi-piece fastener 200. The collet 352 includes a first collet end 352a adjacent the anvil 354, and the first collet end 352a includes a jaw configured to forcibly contact at least a portion of the pull region 224 of the shank 222 of the multi-piece fastener 200.

[0047] In various non-limiting embodiments, the PHD 370 includes a processor operatively coupled to memory. The PHD 370 is configured (e.g., includes sensors and / or circuitry) to measure a load exerted by the collet 352 on the multi-piece fastener 200 during installation of the multi-piece fastener 200 with the installation device 348, thereby determining a measured load. The collet 352 can be retracted into the anvil 354, which also causes forcing contact between the anvil 354 and the fastening collar 202. The measured load may be a direct measurement of the load exerted on the collet 352 during installation by a device (e.g., motor, actuator) and / or the measured load may be an indirect measurement of the load exerted on the collet 352 during installation by measuring the force exerted on the anvil 352 as a result of forcing contact between the fastening collar 202 and the anvil 354.

[0048] The PHD 370 is further configured to measure the stroke length of the collet 352 while applying a load to the collet 352 during installation of the multi-piece fastener 200 with the installation device 348, thereby determining a measured stroke length. The measured stroke length can be an absolute distance the collet 352 moves along the longitudinal axis A1 relative to the anvil 354 during the installation process and / or a relative distance the collet 352 moves along the longitudinal axis A1.

[0049] PHD 370 can also be configured to use the measured force and the measured stroke length to determine whether the fastening collar 202 has deformed to the first feature 234a, the second feature 234b, and / or another feature of the plurality of structural features 234 on the shank 222 of the multi-piece fastener 200 during installation of the multi-piece fastener 200 using the installation device 348. PHD 370 can determine the number of structural features 234 on the shank 222 at which the fastening collar 202 has deformed during the installation process. PHD 370 can be configured to normalize the measured force and the measured stroke length based on a determination that the fastening collar 202 of the multi-piece fastener 200 has deformed to the first feature 234a of the plurality of structural features 234 on the shank 222. PHD 370 can also use the measurements to plot a curve of the measured stroke length versus the measured load during the installation process. PHD 370 can then determine whether the multi-piece fastener 200 is acceptably installed by comparing the number of structural features 234 that the fastening collar 220 has deformed into with a predetermined amount of structural feature threshold, comparing the measured stroke length with a predetermined stroke length threshold, comparing the measured load with a predetermined load threshold, analyzing the measured stroke vs. measured load curve, and / or determining whether the measured stroke vs. load curve passes through predetermined checkboxes or other features.

[0050] PHD 370 can output a determination of whether the multi-piece fastener 200 has been acceptably installed to a display device 362 in signal communication with PHD 370. For example, the display device 362 can be configured to display a first indicia indicating that the fastening collar 202 of the multi-piece fastener 200 has deformed to conform to the first feature 234a of the plurality of structural features 234 or a second indicia indicating that the fastening collar 202 of the multi-piece fastener 200 has not deformed to conform to the first feature 234a of the plurality of structural features 234 based on a determination by PHD 370 of whether the fastening collar 202 of the multi-piece fastener 200 has deformed to conform to the first feature 234a on the shank 222 of the multi-piece fastener 200 during installation using the installation device 348. In various non-limiting embodiments, the display device 362 may be configured to display a first indicia indicating that the multi-piece fastener 200 is acceptably installed (based on a particular applicable standard) or a second indicia indicating that the multi-piece fastener 200 is not acceptably installed.

[0051] 3A , the collet 352 of the installation tool 348 engages the shank 222 of the pin 220 of the multi-piece fastener 200. For example, the collet 352 may be configured to retract into the installation tool 348, causing the collet 352 to forcibly contact the anvil 354 of the installation tool 348. The collet 352 may then close around and forcibly contact, thereby engaging, the tension region 224 of the pin 220. Upon engagement, the collet 352 may apply an axial force to the tension region 224 of the pin 220, which may reduce the gap (if present) between the first layer 344 a and the second layer 344 b of the structure 344 and create forcible contact between the fastening collar 202 and the structure 344.

[0052] The anvil 354 can at least partially deform the fastening collar 202 to fit over the shank 222 of the pin 220, thereby securing the fastening collar 202 to the shank 222. For example, referring to FIG. 3B , contact between the tension region 224 and the collet 352 can cause the collet 352 to retract into the installation tool 348 as the collet 352 contracts, and can also move the pin 220. As the collet 352 contracts, the anvil 354 forcibly contacts the fastening collar 202. After a predetermined force is achieved, the longitudinal portion 208 can at least partially deform in response to the forcible contact between the anvil 354 and the fastening collar 202. For example, the longitudinal portion 208 can be at least partially crimped onto at least a portion of a structural feature 234 on the shank 222. As shown in FIG. 3B , the longitudinal portion 208 is crimped onto at least a first feature 234a.

[0053] During retraction of collet 352, the load applied to collet 352 (i.e., measured load) and the stroke length of collet 352 (i.e., measured stroke length) can be determined by PHD 370. For example, as shown in Figure 4A, PHD 370 plotted a curve 470 of measured stroke length versus measured load as the installation process progressed from the configuration shown in Figure 3A to the configuration shown in Figure 3B. Fastening collar 202 was crimped onto first feature 234a at area 472a on curve 470.

[0054] The collet 352 can continue to retract to the position shown in FIG. 3C. As the collet 352 continues to retract, the anvil 354 forces contact and deforms more of the fastening collar 202. For example, the longitudinal portion 208 can be crimped, at least substantially, to a number of the structural features 234 on the shank 122. As shown in FIG. 3C, the longitudinal portion 208 is crimped onto a first feature 234a, a second feature 234b, a third feature 234c, a fourth feature 234d, and a fifth feature 234e of the plurality of features 234 on the shank 122.

[0055] 3C , after installation of the multi-piece fastener 200 within the structure 344, the fastening collar 202 and head portion 236 of the pin 220 can apply a clamping force to the structure 344, thereby securing the two-piece fastener 200 to the structure 344. In certain non-limiting embodiments, the pin 220 can break along the breakneck groove 240 after installation into the structure 344.

[0056] As the collet 352 continues to retract, the load applied to the collet 352 (i.e., the measured load) and the stroke length of the collet 352 (i.e., the measured stroke length) can be measured by the PHD 370. For example, as shown in FIG. 4B, the PHD 370 continues to plot a curve 470 of measured stroke length versus measured load as the installation process progresses from the configuration shown in FIG. 3B to the configuration shown in FIG. 3C. The fastening collar 202 deformed to conform to the second feature 234b in area 472b of the curve 470. The fastening collar 202 deformed to conform to the third feature 234c in area 472c on the curve 470. The fastening collar 202 deformed to conform to the fourth feature 234d in area 472d on the curve 470. The fastening collar 202 deformed to conform to the fifth feature 234e in area 472e on the curve 470.

[0057] As seen in curve 470 of FIG. 4B , deformation of the fastening collar 202 against the first feature 234a generates a signature 472a within the curve 470 that is different from deformation of the fastening collar 202 against the other features 234-e. Determining the signature generated when the fastening collar 202 is deformed onto the first feature 234a allows for a determination of whether the fastening collar 202 is acceptably installed within a structure. For example, the number of structural features 234 through which the fastening collar 202 is deformed during installation of the multi-piece fastener 200 can be determined using the signature 472a of the first feature 234a as a reference. For example, if the first feature 234a is the first structural feature in a series of structural features 234 contacted by the fastening collar 202, the signature 472a of the first feature 234a can be used as an initial count of the structural features. In various non-limiting embodiments, if the first feature 234a is the first structural feature in a series of structural features 234 contacted by the fastening collar 202, the signature 472a of the first feature 234a can be used to verify the thickness of the structure by measuring the stroke length from the start of installation of the collar 202 to the first feature 234a and comparing it to a predetermined value. However, in certain embodiments, the first feature 234a can be in a different location and the structural feature 234a can be counted before the first feature 234a.

[0058] In various non-limiting embodiments, the first feature 234a can be used to normalize the curves of measured force and measured stroke length. For example, FIG. 5 shows a first curve 580 plotting the measured force and measured stroke length during installation of a first multi-piece fastener and a second curve 582 plotting the measured force and measured stroke length during installation of a second multi-piece fastener. Region 584 of first curve 580 corresponds to the point where the fastening collar of the first multi-piece fastener was crimped onto the first feature of the shank of the first fastener. Region 586 of second curve 582 corresponds to the point where the fastening collar of the second multi-piece fastener was crimped onto the first feature of the shank of the second fastener. Both the first and second multi-piece fasteners were installed acceptably. As shown, the initial region 580a of the first curve 580 and the initial region 582a of the second curve 582 are different, which can lead to variability in determining whether each multi-piece fastener is acceptably installed when only the measured stroke length or the measured load is considered. However, the second region 580b of the first curve 580 and the second region 580b of the second curve 582 are substantially similar. When the first curve 580 and the second curve 582 are normalized using the regions 584 and 586, respectively, as references, they are substantially similar. Therefore, normalization based on the deformation of the fastening collar 202 relative to the first characteristic can more accurately determine whether the multi-piece fastener 200 is acceptably installed.

[0059] In various non-limiting embodiments, the first curve 580 and the second curve 582 can be aligned to the measured load of the signature 472a of the first feature 234a (e.g., the measured load at the center of the first signature 472a). The stroke length before the first signature 472a can then be determined and compared to a predetermined value to determine if the collar 202 is in a desired position relative to the pin 220, which can also be used to determine the thickness of the structure 344. The stroke length to the end of placement after the first signature 472a can then be determined and compared to a predetermined value to determine if the collar 202 has been placed to a desired level.

[0060] Deformation of longitudinal portion 208 can secure fastening collar 202 to pin 220, thereby securing multi-piece fastener 200 to at least a portion of structure 344. In this manner, for example, first layer of material 344a and second layer of material 344b of structure 344 are secured together (e.g., restrained from axial movement along longitudinal axis A1 of multi-piece fastener 200).

[0061] 3A-3C, the installation tool may be a pulling tool or a compressing tool (not shown). For example, as known in the art, a compressing tool may simultaneously apply a compressive force to the fastening collar 202 and the second pin end 230 of the pin 220. The compressive force may deform the fastening collar 202 to fit onto the shank 222 of the pin 220, thereby securing the fastening collar 202 onto the shank 222.

[0062] Referring to FIG. 6 , in various non-limiting embodiments, a multi-piece fastener according to the present disclosure can be installed in a method for securing a structural member. In step 602, the first pin end 228 of the multi-piece fastener 200 is inserted into the hole 346 of the structural member 344. In step 604, the tension region of the pin of the multi-piece fastener is forced into contact with the jaws of a collet of an installation device. In step 606, the load applied by the collet (i.e., measured load) and the stroke length of the collet (i.e., measured stroke length) are measured during installation of the multi-piece fastener with the installation device. The fastening collar is forced into contact with the anvil of the installation device, and the tension region is moved distally from the fastening collar using the collet of the fastening collar installation device, thereby deforming the fastening collar to conform to the shank of the pin and securing at least a portion of the multi-piece fastener within the structure in step 608. In step 610, the measured force and the measured stroke length are used to determine whether the collar has deformed to conform to a first feature of the shank of the multi-piece fastener during installation of the multi-piece fastener with the installation device. In various non-limiting embodiments, as shown in step 612, the measured force and the measured stroke length can be normalized based on a determination that the collar of the multi-piece fastener has deformed to conform to a first feature of the plurality of structural features on the shank. In various non-limiting embodiments, indicia can be displayed on a display of the installation device to indicate whether the multi-piece fastener was acceptably installed.

[0063] Various aspects of the present invention include, but are not limited to, those listed in the following numbered paragraphs: 1. A multi-piece fastener comprising: a fastening collar including a first collar end and a second collar end, the collar cavity extending from the first collar end to the second collar end; a pin configured to be at least partially received by the collar cavity, a first pin end; a second pin end; and a pin comprising: a shank extending intermediate the first pin end and the second pin end; the shank comprises a plurality of structural features; and a first feature of the plurality of structural features having a first configuration and a second feature of the plurality of structural features having a second configuration, the first configuration and the second configuration being different. 2. The multi-piece fastener of claim 1, wherein the plurality of structural features includes a first groove and a second groove, and wherein at least one dimension of the first groove and the second groove differs. 3. The multi-piece fastener of claim 2, wherein the at least one dimension of the first groove and the second groove is selected from groove crest and groove depth. 4. The multi-piece fastener of any of claims 1, wherein the plurality of structural features include a first annular shoulder and a second annular shoulder, and at least one dimension of the first annular shoulder and the second annular shoulder differs. 5. The multi-piece fastener of claim 1, wherein the plurality of structural features include a first thread and a second thread, and at least one dimension of the first thread and the second thread differs. 6. The multi-piece fastener of paragraph 5, wherein at least one dimension of the first thread and the second thread is selected from thread depth, internal thread diameter, external thread diameter, and thread pitch. 7. The multi-piece fastener of any one of claims 1 to 6, wherein the fastening collar is generally cylindrical. 8. The multi-piece fastener of any one of claims 1 to 7, wherein the fastening collar comprises a flange, the first pin end comprises a head portion, and the second pin end comprises a tension region. 9. The multi-piece fastener of any one of paragraphs 1 to 8, wherein the multi-piece fastener is adapted to be installed in a hole in a structure. 10. The multi-piece fastener of claim 9, wherein the structure is at least one of an aerospace part or component, an automotive part or component, a transportation part or component, and a building and construction part or component. 11. The multi-piece fastener according to any one of claims 1 to 10, wherein the multi-piece fastener comprises at least one of a metal, a metal alloy, and a composite material. 12. The multi-piece fastener of any one of claims 1 to 11, wherein the shank diameter ranges from 0.06 inches to 4 inches (0.1524 cm to 10.16 cm). 13. A rock bolt comprising the multi-piece fastener described in any one of paragraphs 1 to 12. 14. A method for fastening, comprising: inserting a second pin end of the multi-piece fastener of claim 1 into a hole in a structure; forcing the tension region of the pin of the multi-piece fastener into contact with an installation device; measuring a load applied to the multi-piece fastener by the installation device and a stroke length of the collet during installation of the multi-piece fastener with the installation device; forcing the fastening collar into contact with the anvil of the installation device and moving the tension region distally from the fastening collar to deform the fastening collar over the shank of the pin and secure at least a portion of the multi-piece fastener to the structure; utilizing the measured force and the measured stroke length to determine whether the collar has deformed to conform to the first feature of the shank of the multi-piece fastener during installation of the multi-piece fastener using the installation device. 15. The method of claim 14, further comprising normalizing the measured force and the measured stroke length based on a determination that the collar of the multi-piece fastener has been deformed to conform to a first feature of a plurality of structural features on the shank. 16. A multi-piece fastener installation device comprising: a housing defining a housing cavity; an anvil within the housing cavity configured to forcibly contact at least a portion of a collar of a multi-piece fastener; a collet within the housing cavity, the collet including a first collet end adjacent the anvil, the first collet end configured to forcibly contact at least a portion of a tension region of a shank of the multi-piece fastener; 1. A programmable hardware device, comprising: measuring a load applied by the collet to the multi-piece fastener during installation of the multi-piece fastener using the installation device; measuring the stroke length of the collet while applying a load during installation of the multi-piece fastener using the installation device; and a programmable hardware device configured to utilize the measured force and the measured stroke length to determine whether the collar of the multi-piece fastener has deformed to conform to a first feature of a plurality of structural features on the shank of the multi-piece fastener during installation of the multi-piece fastener using the installation device. 17. The multi-piece fastener installation device of claim 16, wherein the first feature is different from a second feature of the plurality of structural features on the shank of the multi-piece fastener. 18. The multi-piece fastener installation apparatus of any of claims 16-17, further comprising: a display device in signal communication with the programmable hardware device, the display device configured to display, based on a determination by the programmable hardware device whether the fastening collar of the multi-piece fastener has deformed to conform to the first one of the plurality of structural features, a second indicia indicating that the collar of the multi-piece fastener has not deformed to conform to the first one of the plurality of structural features, or a combination of the first and second indicia, based on a determination by the programmable hardware device whether the fastening collar of the multi-piece fastener has deformed to conform to the first one of the plurality of structural features on the shank of the multi-piece fastener during installation of the multi-piece fastener with the installation apparatus. 19. The multi-piece fastener installation apparatus of any one of paragraphs 16 to 19, wherein the programmable hardware device is further configured to normalize the measured force and the measured stroke length based on a determination that the collar of the multi-piece fastener has deformed onto a first feature portion of a plurality of structural features on the shank.

[0064] In this specification, 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 the 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.

[0065] Additionally, any numerical range recited herein includes all subranges encompassed within the recited range. For example, a range of "1 to 10" includes all subranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, i.e., all subranges having a minimum value of 1 or greater and a maximum value 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 explicitly recite subranges encompassed within the explicitly recited range. All such ranges are inherently described herein.

[0066] 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 particular 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 component. Furthermore, unless the context requires otherwise, the use of a singular noun includes the plural and the use of a plural noun includes the singular.

[0067] 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 specific example is intended to be representative of its classification, and the absence of inclusion of particular components, devices, apparatus, operations / actions, and objects should not be construed as limiting. While the present 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 or inventions described herein are at least as broad as they are claimed, and not more narrowly defined by the specific exemplary aspects provided herein.

Claims

1. A multi-piece fastener comprising: a fastening collar including a first collar end and a second collar end, the collar cavity extending from the first collar end to the second collar end; a pin configured to be at least partially received by the collar cavity, a first pin end; a second pin end; and a pin comprising: a shank extending intermediate the first pin end and the second pin end; the shank comprises a plurality of structural features; and a first feature of the plurality of structural features having a first configuration and a second feature of the plurality of structural features having a second configuration, the first configuration and the second configuration being different.

2. 10. The multi-piece fastener of claim 1, wherein the plurality of structural features includes a first groove and a second groove, and wherein at least one dimension of the first groove and the second groove differs.

3. 3. The multi-piece fastener of claim 2, wherein the at least one dimension of the first groove and the second groove is selected from groove crest and groove depth.

4. 2. The multi-piece fastener of claim 1, wherein the plurality of structural features includes a first annular shoulder and a second annular shoulder, and wherein at least one dimension of the first annular shoulder and the second annular shoulder differs.

5. The multi-piece fastener of claim 1 , wherein the plurality of structural features includes a first thread and a second thread, and wherein at least one dimension of the first thread and the second thread differs.

6. 6. The multi-piece fastener of claim 5, wherein at least one dimension of the first thread and the second thread is selected from a thread depth, an internal thread diameter, an external thread diameter, and a thread pitch.

7. The multi-piece fastener of claim 1 , wherein the fastening collar is generally cylindrical.

8. 2. The multi-piece fastener of claim 1, wherein the fastening collar comprises a flange, the first pin end comprises a head portion, and the second pin end comprises a tension region.

9. The multi-piece fastener of claim 1 , wherein the multi-piece fastener is adapted to be installed in a hole in a structure.

10. 10. The multi-piece fastener of claim 9, wherein the structure is at least one of an aerospace part or component, an automotive part or component, a transportation part or component, and a building and construction part or component.

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

12. The multi-piece fastener of claim 1, wherein the shank diameter ranges from 0.06 inches to 4 inches (0.1524 cm to 10.16 cm).

13. A rock bolt comprising the multi-piece fastener of claim 1.

14. A method for fastening, comprising: inserting a second pin end of the multi-piece fastener of claim 1 into a hole in a structure; forcing the tension region of the pin of the multi-piece fastener into contact with an installation device; measuring a load applied to the multi-piece fastener by the installation device and a stroke length of the collet during installation of the multi-piece fastener with the installation device; forcing the fastening collar into contact with the anvil of the installation device and moving the tension region distally from the fastening collar to deform the fastening collar over the shank of the pin and secure at least a portion of the multi-piece fastener to the structure; utilizing the measured force and the measured stroke length to determine whether the collar has deformed to conform to the first feature of the shank of the multi-piece fastener during installation of the multi-piece fastener using the installation device.

15. 15. The method of claim 14, further comprising normalizing the measured force and the measured stroke length based on a determination that the collar of the multi-piece fastener has been deformed to conform to a first feature of a plurality of structural features on the shank.

16. 1. A multi-piece fastener installation device comprising: a housing defining a housing cavity; an anvil within the housing cavity configured to forcibly contact at least a portion of a collar of a multi-piece fastener; a collet within the housing cavity, the collet including a first collet end adjacent the anvil, the first collet end configured to forcibly contact at least a portion of a tension region of a shank of the multi-piece fastener; 1. A programmable hardware device, comprising: measuring a load applied to the multi-piece fastener by the collet during installation of the multi-piece fastener using the installation device; measuring the stroke length of the collet while applying a load during installation of the multi-piece fastener using the installation device; and a programmable hardware device configured to utilize the measured force and the measured stroke length to determine whether the collar of the multi-piece fastener has deformed to conform to a first feature of a plurality of structural features on the shank of the multi-piece fastener during installation of the multi-piece fastener using the installation device.

17. 17. The multi-piece fastener installation device of claim 16, wherein the first feature is different from a second feature of the plurality of structural features on the shank of the multi-piece fastener.

18. 17. The multi-piece fastener installation device of claim 16, 17. The multi-piece fastener installation apparatus of claim 16, further comprising: a display device in signal communication with the programmable hardware device, the display device configured to display, based on a determination by the programmable hardware device whether the fastening collar of the multi-piece fastener has deformed to conform to the first one of a plurality of structural features on the shank of the multi-piece fastener during installation of the multi-piece fastener with the installation apparatus, a first indicia indicating that the collar of the multi-piece fastener has deformed to conform to the first one of a plurality of structural features, a second indicia indicating that the collar of the multi-piece fastener has not deformed to conform to the first one of a plurality of structural features, or a combination of the first and second indicia.

19. 17. The multi-piece fastener installation apparatus of claim 16, wherein the programmable hardware device is further configured to normalize the measured force and the measured stroke length based on a determination that the collar of the multi-piece fastener has been deformed to conform to the first feature of a plurality of structural features on the shank.

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