Patent Description:
Vehicle frames, storage racks, solar panel sub-structures, aircraft parts, and other structures can include numerous mechanical fasteners. For example, a structural fastener can be installed in a bore of a structural component to secure parts together. Properly installing a structural fastener into a bore presents challenges. <CIT> discloses a swage type fastener including a pin and a collar adapted to be swaged onto the pin by the application of a relative axial force by an installation tool.

According to one aspect of the present disclosure, a multi-piece fastener is provided. The multi-piece fastener comprises a fastening collar and a pin. The fastening collar comprises a first collar end, a second collar end, and a collar cavity. The 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 comprises a first pin end comprising a head portion, a second pin end comprising a pull region, and a shank. The pull region is generally cylindrical and smooth and is configured to form at least one of an annular shoulder, a groove, a thread, and other feature thereon responsive to forcible contact from a fastening collar installation apparatus. The shank extends intermediate the first pin end and the second pin end. The fastening collar is configured to be deformed onto at least a region of the shank.

According to another aspect of the present disclosure, a fastening collar installation apparatus is provided. The fastening collar installation apparatus comprises a housing, an anvil, and a collet. The housing comprises a first housing end, a second housing end, and a housing cavity extending from the first housing end to the second housing end. The anvil and the collet are positioned within the housing cavity. The collet comprises a first collet end adjacent to the anvil. The first collet end comprises jaws configured to forcibly contact at least a portion of a pull region of a multi-piece fastener and to form at least one of an annular shoulder, a groove, a thread, and other feature on the pull region.

According to yet another aspect of the present disclosure, a method for fastening is provided. The method comprises inserting a second pin end of a pin of a multi-piece fastener into a bore in a structure. The multi-piece fastener comprises a fastening collar and the pin. The fastening collar comprises a first collar end, a second collar end, and a collar cavity. The 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 comprises a first pin end comprising a head portion, a second pin end comprising a pull region, and a shank. The pull region is generally cylindrical and smooth and is configured to form at least one of an annular shoulder, a groove, a thread, and other feature responsive to forcible contact from a fastening collar installation apparatus. The shank extends intermediate the first pin end and the second pin end. The fastening collar is configured to be deformed onto the shank. Additionally, the method comprises passing at least a portion of the second pin end through the collar cavity. The pull region of the pin is forcibly contacted with jaws of a collet of a fastening collar installation apparatus, and at least one of an annular shoulder, a groove, a thread, and other feature is formed on the pull region by the jaws. The fastening collar is forcibly contacted with an anvil of the fastening collar installation apparatus, and the pull region is moved distal from the fastening collar utilizing the collet of the fastening collar installation apparatus, thereby deforming the fastening collar onto the shank of the pin and securing at least a portion of the multi-piece fastener in the structure.

It will be understood that the invention disclosed and described in this specification is not limited to the aspects summarized in this Summary. The reader will appreciate the foregoing details, as well as others, upon considering the following detailed description of various non-limiting and non-exhaustive aspects according to this specification.

The features and advantages of the examples presented herein, and the manner of attaining them, will become more apparent, and the examples will be better understood, by reference to the following description taken in conjunction with the accompanying drawings, wherein:.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate certain embodiments, in one form, and such exemplifications are not to be construed as limiting the scope of the appended claims in any manner.

Various embodiments are described and illustrated herein to provide an overall understanding of the structure, function, and use of the multi-piece fasteners , and methods of fastening. The various embodiments described and illustrated herein are non-limiting and non-exhaustive. Thus, the invention is not limited by the description of the various non-limiting and non-exhaustive embodiments disclosed herein. Rather, the invention is defined solely by the claims. The features and characteristics illustrated and/or described in connection with various embodiments may be combined with the features and characteristics of other embodiments. Such modifications and variations are intended to be included within the scope of this specification. As such, the claims may be amended to recite any features or characteristics expressly or inherently described in, or otherwise expressly or inherently supported by, this specification. Further, Applicant reserves the right to amend the claims to affirmatively disclaim features or characteristics that may be present in the prior art. The various embodiments disclosed and described in this specification can comprise, consist of, or consist essentially of the features and characteristics as variously described herein.

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

In this specification, unless otherwise indicated, all numerical parameters are to be understood as being prefaced and modified in all instances by the term "about," in which the numerical parameters possess the inherent variability characteristic of the underlying measurement techniques 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 described herein should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Any numerical range recited herein includes all sub-ranges subsumed within the recited range. For example, a range of "<NUM> to <NUM>" includes all sub-ranges between (and including) the recited minimum value of <NUM> and the recited maximum value of <NUM>, that is, having a minimum value equal to or greater than <NUM> and a maximum value equal to or less than <NUM>. Also, all ranges recited herein are inclusive of the end points of the recited ranges. For example, a range of "<NUM> to <NUM>" includes the end points <NUM> and <NUM>. Any maximum numerical limitation recited in this specification is intended to include all lower numerical limitations subsumed therein, and any minimum numerical limitation recited in this specification is intended to include all higher numerical limitations subsumed therein. Accordingly, Applicant reserves the right to amend this specification, including the claims, to expressly recite any sub-range subsumed within the ranges expressly recited. All such ranges are inherently described in this specification.

The grammatical articles "a," "an," and "the," as used herein, are intended to include "at least one" or "one or more," unless otherwise indicated, even if "at least one" or "one or more" is expressly used in certain instances. Thus, the foregoing grammatical articles are used herein to refer to one or more than one (i.e., to "at least one") of the particular identified elements. Further, the use of a singular noun includes the plural, and the use of a plural noun includes the singular, unless the context of the usage requires otherwise.

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

Installing a lockbolt can comprise axially moving the pin of the fastener distal from a fastening collar of the fastener system and swaging the fastening collar. Moving the pin can require a collet of an installation tool to engage or otherwise grip the pin. Typically, the pin can comprise a pull section with a gripping feature that can be engaged by the collet, such as, for example, an annular shoulder, a groove, a thread, or other feature. The gripping feature can be difficult to form during a rolling procedure. Additionally, forming the gripping feature on the pull section of the pin adds time and cost to the manufacturing process. Accordingly, multi-piece fasteners, fastening collar installation apparatus, and methods of fastening are provided that may not require a gripping feature to be provided on a pull region of a pin of the multi-piece fastener.

Additionally, the multi-piece fasteners, fastening collar installation apparatus, and methods of fastening according to the present disclosure can provide a visual indication that the fastener has been installed, which can save inspection time.

<FIG> illustrate a non-limiting embodiment of a multi-piece fastener <NUM> according to the present disclosure. The multi-piece fastener <NUM> can be adapted to be installed in a bore in a structure (e.g., as illustrated in <FIG> and discussed below). The multi-piece fastener <NUM> can comprise at least two components, such as, for example, a fastening collar <NUM> and a pin <NUM> as illustrated in <FIG>, or in some non-limiting embodiments, at least three components (not shown). In various non-limiting embodiments, the multi-piece fastener <NUM> can comprise a two-piece assembly, including the fastening collar <NUM> and the pin <NUM>. In some non-limiting embodiments, the multi-piece fastener <NUM> can comprise a lockbolt. For example, the lockbolt can be a structural lockbolt fastener, such as, for example, a structural rivet, a structural bolt, or a structural stud.

The fastening collar <NUM> can comprise a first collar end <NUM>, a second collar end <NUM>, an elongate portion <NUM> disposed intermediate the first collar end <NUM> and the second collar end <NUM>, and a collar cavity <NUM> extending through the elongate portion <NUM> from the first collar end <NUM> to the second collar end <NUM>. The elongate portion <NUM> can define a longitudinal axis of the fastening collar <NUM> and/or the multi-piece fastener <NUM>. An inner surface <NUM> of the elongate portion <NUM> defining the collar cavity <NUM> can comprise at least one of a substantially cylindrical region, a threaded region, an annular shoulder, a groove, and other feature depending on the desired application. The fastening collar <NUM> can be sized and configured to engage with a fastening collar installation tool. Responsive to the engagement, the fastening collar <NUM> can be deformed onto a shank <NUM> of a pin <NUM> of the multi-piece fastener <NUM> to achieve a desired clamping force between the fastening collar <NUM> and the pin <NUM>.

The pin <NUM> can comprise a first pin end <NUM>, a second pin end <NUM>, and the shank <NUM>. The shank <NUM> can comprise a shape and size suitable to be received by the collar cavity <NUM> of the fastening collar <NUM>, such as, for example, a generally cylindrical shape. The shank <NUM> can extend intermediate the first pin end <NUM> and the second pin end <NUM> and can be dimensioned so that it can be disposed at least partially through the collar cavity <NUM>. When the shank <NUM> is inserted in the collar cavity <NUM>, the second pin end <NUM> can be disposed adjacent to the second collar end <NUM>, and the first pin end <NUM> can be disposed adjacent to the first collar end <NUM>. The first pin end <NUM> can comprise a head portion <NUM> configured to inhibit the pin <NUM> from traversing completely through a bore in a structure. For example, a diameter of a bore in a structure can comprise a diameter less than a diameter of the head portion <NUM> so that the head portion <NUM> cannot pass through the bore.

The collar cavity <NUM> can be configured to receive the pin <NUM>. For example, the collar cavity <NUM> can comprise a first diameter, Ø<NUM>, greater than a second diameter, Ø<NUM>, of the shank <NUM>. The fastening collar <NUM> can comprise a flange <NUM> comprising a third diameter, Ø<NUM>, sized and configured in order to inhibit the flange <NUM> of the fastening collar <NUM> from traversing through a bore in a structure. In various non-limiting embodiments, the fastening collar <NUM> can be generally cylindrical.

In various non-limiting embodiment, the second diameter, Ø<NUM>, of the shank <NUM> can be at least <NUM> (<NUM> inches), such as, for example, at least <NUM> (<NUM> inch), at least <NUM> (<NUM> inches), or at least <NUM> (<NUM> inch). In various non-limiting embodiments, the second diameter, Ø<NUM>, of the shank <NUM> can be no greater than <NUM> (<NUM> inches), such as, for example, no greater than <NUM> (<NUM> inch), no greater than <NUM> (<NUM> inches), or no greater than <NUM> (<NUM> inch). In various non-limiting embodiments, the second diameter, Ø<NUM>, of the shank <NUM> can be in a range of <NUM> to <NUM> (<NUM> inches to <NUM> inches), such as, for example, <NUM> to <NUM> (<NUM> inches to <NUM> inches), or <NUM> to <NUM> (<NUM> inches to <NUM> inches).

The second pin end <NUM> can comprise a pull region <NUM> configured to be engaged by a fastening collar installation apparatus (e.g., fastening collar installation apparatus <NUM>, as illustrated in <FIG> and discussed below). The pull region <NUM> can comprise an axial length, l, sized to be engaged by an installation tool. For example, in various non-limiting embodiments, the axial length, l, can be at least <NUM> times the second diameter, Ø<NUM>, of the shank <NUM>, such as, for example, at least <NUM> times the second diameter, Ø<NUM>, of the shank <NUM>, at least <NUM> times the second diameter, Ø<NUM>, of the shank <NUM>, or at least <NUM> times the second diameter, Ø<NUM>, of the shank <NUM>. In various non-limiting embodiments, the axial length, l, can be no greater than <NUM> times the second diameter, Ø<NUM>, of the shank <NUM>, such as, for example, no greater than <NUM> times the second diameter, Ø<NUM>, of the shank <NUM>, no greater than <NUM> the second diameter, Ø<NUM>, of the shank <NUM>, or no greater than <NUM> times the second diameter, Ø<NUM>, of the shank <NUM>. In certain non-limiting embodiments, the axial length, l, can be in a range of <NUM> to <NUM> times the second diameter, Ø<NUM>, of the shank <NUM>, such as for example, <NUM> times to <NUM> times the second diameter, Ø<NUM>, of the shank <NUM>.

In certain non-limiting embodiments, the pull region <NUM> may not comprise a taper. In various other non-limiting embodiments, not in line with the claimed invention, the pull region <NUM> may comprise a taper or a reverse taper. For example, as one moves along the pull region <NUM> away from the shank <NUM> along a longitudinal axis of the pin <NUM>, the diameter of the pull region <NUM> can decrease. In certain other non-limiting embodiments, the pull region <NUM> can comprise a reverse taper in which, as one moves along the pull region <NUM> away from the shank <NUM> along the longitudinal axis of the pin <NUM>, the diameter of the pull region <NUM> can increase.

In certain non-limiting embodiments, according to the claimed invention, the pull region <NUM> is generally cylindrical and smooth. For example, the pull region <NUM> can be free of an annular shoulder, grooves, threads, or other features prior to forcible contact with a fastening collar installation apparatus. In various non-limiting embodiments, the annular shoulder, groove, thread, or other feature can form on the pull region <NUM> responsive to forcible contact with a fastening collar installation apparatus. The formation of the annular shoulder, groove, thread, and/or other feature on the pull region <NUM> can be responsive to installation of the multi-piece fastener <NUM> into a structure and, thus, provides a visual indication that the multi-piece fastener <NUM> has been installed into the structure.

The shank <NUM> can define the longitudinal axis of the pin <NUM> and/or the multi-piece fastener <NUM>. The shank <NUM> can be configured to engage the fastening collar <NUM> on installation in order to secure the shank <NUM> to the fastening collar <NUM>. In various non-limiting embodiments, upon engagement of the pin <NUM> and the collar <NUM> when the components are installed, the longitudinal axis of the pin <NUM> and the longitudinal axis of the fastening collar <NUM> can be substantially aligned and form the longitudinal axis of the multi-piece fastener <NUM>.

In various non-limiting embodiments, the shank <NUM> of the pin <NUM> can comprise at least one of a generally smooth region, a threaded region, an annular shoulder, a groove, and other feature that is adapted to engage the surface <NUM> of the fastening collar <NUM> on installation. The threaded region, annular shoulder, groove, and/or other feature can be external relative to the shank <NUM>. In various non-limiting embodiments, all or a portion of the shank <NUM> includes grooves. For example, as shown in <FIG>, the shank <NUM> of the pin <NUM> includes grooves <NUM>. In other non-limiting embodiments, all or a portion of the shank <NUM> lacks grooves. In various non-limiting embodiments, a portion of the shank <NUM> includes an annular shoulder. In other non-limiting embodiments, the shank <NUM> lacks an annular shoulder. In various non-limiting embodiments, a portion of the shank <NUM> includes a threaded portion. In other non-limiting embodiments, the shank <NUM> lacks a threaded portion.

The collar cavity <NUM> of the fastening collar <NUM> can be configured to at least partially receive the shank <NUM> of the pin <NUM> therein. For example, the collar cavity <NUM> can comprise a shape suitable to receive the shank <NUM> of the pin <NUM>, such as, for example, a generally cylindrical shape. During and/or after introduction of the shank <NUM> into the collar cavity <NUM>, the fastening collar <NUM> can be at least partially deformed (e.g., swaged) onto the shank <NUM> responsive to forcible contact between the fastening collar <NUM> and a fastening collar installation apparatus, as described below. The deformation can secure the fastening collar <NUM> to the shank <NUM>.

In various non-limiting embodiments, the pin <NUM> may not comprise a breakneck groove or other feature configured to fracture upon installation of the multi-piece fastener <NUM>, and the pull region <NUM> may stay intact after installation. In various other non-limiting embodiments, the pin <NUM> may comprise a breakneck groove (not shown) or other feature configured to fracture upon installation of the multi-piece fastener <NUM>. In certain other non-limiting embodiments, the pin <NUM> may not comprise a breakneck groove and may still be configured to fracture upon installation of the multi-piece fastener <NUM>. Thus, according to various non-limiting embodiments, the multi-piece fastener <NUM> according to the present disclosure, may be installed into a structure without fracturing of a breakneck groove or other feature, or a breakneck groove or other feature may be provided and may be fractured upon installation of the multi-piece fastener into the structure.

The multi-piece fastener system according to the present disclosure can comprise at least one of a metal, a metal alloy, a composite material, and another suitable material. For example, in various non-limiting embodiments, the multi-piece fastener <NUM> can comprise 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 multi-piece fastener <NUM> comprises steel, such as, for example, stainless steel.

<FIG> illustrate a non-limiting embodiment of fastening collar installation apparatus <NUM> according to the present disclosure. The fastening collar installation apparatus <NUM> can engage at least a portion of a fastener system (e.g., the pull region <NUM> of the pin <NUM> of the fastener system illustrated in <FIG>) and/or deform a portion of the fastener system (e.g., deform the fastening collar <NUM> and/or break the pin <NUM> of the multi-piece fastener system <NUM> illustrated in <FIG>). The fastening collar installation apparatus <NUM> can be configured with various components in order to engage a pin of the multi-piece fastener, deform the fastening collar onto the pin, and/or break the pin. For example, the fastening collar installation apparatus <NUM> can comprise an anvil <NUM>, a housing <NUM>, and a collet <NUM>.

The housing <NUM> can be configured to receive and/or retain various components. For example, the housing <NUM> can comprise a housing cavity <NUM> extending along a longitudinal axis of the housing <NUM> from a first housing end <NUM> to the second housing end <NUM>. In various non-limiting embodiments, the housing <NUM> can be substantially cylindrical. The housing cavity <NUM> can be configured to at least partially receive the collet <NUM>.

The anvil <NUM> can be configured to engage and/or deform a fastening collar of a multi-piece fastener system (e.g., fastening collar <NUM> in <FIG>). For example, in various non-limiting embodiments, the anvil <NUM> can be operatively coupled to the housing <NUM> and positioned adjacent to the first housing end <NUM>. In various non-limiting embodiments, the anvil <NUM> is in direct contact with the first housing end <NUM>. The anvil <NUM> can comprise an anvil cavity <NUM> extending along a longitudinal axis of the anvil <NUM>. The anvil cavity <NUM> can be configured to receive at least a portion of the multi-piece fastener <NUM>, such as, for example, at least a portion of the fastening collar <NUM> and/or the pin <NUM>. For example, in various non-limiting embodiments, the anvil <NUM> can have a toroidal shape.

The collet <NUM> can be sized and configured such that the collet <NUM> can engage and/or move at least a portion of a fastener system (e.g., the pull region <NUM> of the pin <NUM> of the multi-piece fastener <NUM>). The collet <NUM> can be positioned within the housing cavity <NUM> of the housing <NUM> and configured to move relative to the housing <NUM> and/or anvil <NUM> in order to draw a multi-piece fastener <NUM> engaged with the collet <NUM> into contact with the anvil <NUM>, as described below with reference to <FIG>.

In various non-limiting embodiments, the collet <NUM> can comprise a first collet end <NUM> adjacent to the anvil <NUM>, a second collet end <NUM>, a collet cavity <NUM> extending from the first collet end <NUM>, and an elongate portion <NUM>. The elongate portion <NUM> can comprise at least two fingers formed by at least two axial channels formed in the elongate portion <NUM>. For example, the elongate portion <NUM> can comprise three fingers 262a-c formed by three axial channels 264a-c as illustrated in <FIG>. In certain non-limiting embodiments, the axial channels 264a-c can be substantially parallel to a longitudinal axis of the collet <NUM>. In various non-limiting embodiments, the fingers 262a-c can be radially spaced about the longitudinal axis of the collet <NUM>, and in various non-limiting embodiments, the fingers 262a-c can be substantially equally radially spaced about the longitudinal axis of the collet <NUM>. Equally radially spacing the fingers 262a-c about the longitudinal axis of the collet <NUM> can facilitate centering of a fastening collar within the collet cavity <NUM> when the fastening collar installation apparatus <NUM> is in use.

The first collet end <NUM> can comprise jaws to engage at least a portion of a fastener (e.g., the pull region <NUM>). For example, in various non-limiting embodiments, each finger 262a-c can comprise a respective jaw 256a-c extending inwardly relative to the longitudinal axis of the collet <NUM> and the collet cavity <NUM>. In various non-limiting embodiments, the jaws 256a-c can comprise an annular shoulder (not shown), a groove, a thread, and/or other feature (not shown). For example, referring to <FIG>, a collet <NUM> is provided that comprises jaws 356a-b with grooves <NUM>. As shown in the non-limiting embodiment illustrated in <FIG>, a collet <NUM> is provided comprising jaws 456a-b including threads <NUM>. In various non-limiting embodiments, the jaws 256a-c, 356a-b, and 456a-b can comprise a <NUM>-degree/<NUM>-degree chuck draw.

Referring again to <FIG>, the jaws 256a-c, according to the claimed invention, are configured to forcibly contact at least a portion of a pull region <NUM> of the pin <NUM> of a multi-piece fastener <NUM> and to form, for example, an annular shoulder, a groove, a thread, and/or other feature on the pull region <NUM>. In various non-limiting embodiments, the jaws 256a-c can cold form an annular shoulder, a groove, a thread, and/or other feature onto the pull region <NUM> of the pin <NUM>. The process of forming an annular shoulder, a groove, a thread, and/or other feature on the pull region <NUM> can increase the tensile strength and/or shear strength of the pin <NUM>, which can increase the reliability of the multi-piece fastener <NUM> after installation. Additionally, forming the annular shoulder, groove, thread, and/or other feature on a generally cylindrical and smooth pull region <NUM> can increase the engagement between the collet <NUM> and the pin <NUM> compared to engagement between a collet and a pin pull region including a preformed annular shoulder, groove, thread, and/or other feature.

In various non-limiting embodiments, the fastening collar installation apparatus <NUM> may form a single annular shoulder, groove, thread, or other feature on the pull region <NUM> of the pin <NUM>. In certain non-limiting embodiments, the fastening collar installation apparatus <NUM> may form at least two annular shoulders, grooves, threads and/or other features on the pull region <NUM> of the pin <NUM>.

The collet <NUM> can be a single, continuous piece or can comprise multiple pieces. For example, the fingers 262a-c can be joined together by bonding or other techniques or can be formed from a single piece of material. In certain non-limiting embodiments, the fingers 262a-c can be independently moveable relative to one another and are not joined together.

The collet <NUM> can be independently moveable relative to the housing <NUM> and/or anvil <NUM>. For example, after engagement with the pull region <NUM> of the multi-piece fastener <NUM>, the collet <NUM>, including the jaws 256a-c, can be configured to retract within the housing <NUM> and move the pull region <NUM> distal from the fastening collar <NUM> of the multi-piece fastener <NUM>. The movement of the collet <NUM> can be responsive to a linear force acting on the collet.

For example, in various non-limiting embodiments of the installation tool <NUM> the second collet end <NUM> can be configured to engage a tool that can generate a linear force, such as, for example, a piston of a powered installation tool. The powered installation tool can be a battery-powered tool, such as, for example, at least one of a Huck® Range Force™ battery-powered installation tool; a pneumatic tool, such as, for example, a Huck® <NUM> pneumatic tool; and a hydraulic tool, such as, for example, a Huck® SF hydraulic tool, all available from Arconic Fasteners, Waco, Texas. In various non-limiting embodiments, as illustrated in <FIG>, the collet <NUM> can be engaged with an adapter <NUM> that can engage a tool that can generate a linear force.

The fastening collar installation apparatus <NUM> can comprise at least one of a metal, a metal alloy, a composite material, and another suitable material. For example, in various non-limiting embodiments, the fastening collar installation apparatus <NUM> can comprise 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 collet <NUM> can comprise a first material with a first hardness, and the pin <NUM> can comprises a second material with a second hardness. In certain non-limiting embodiments, the first hardness can be greater than the second hardness such that the collet <NUM> can deform the pull region <NUM> of first pin end <NUM> of the pin <NUM>. Therefore, the jaws 256a-c can apply a force to a surface of the pull region <NUM> that is greater than a yield strength of the second material in order to form an annular shoulder, a groove, a thread, and /or other feature on the pull region <NUM>.

As illustrated in <FIG>, the multi-piece fastener <NUM> can be installed into a bore <NUM> of a structure <NUM>. As illustrated, the bore <NUM> can extend through the structure <NUM> from a first side <NUM> to a second side <NUM>.

The structure <NUM> can comprise, for example, at least one of a metal, a metal alloy, a composite material, or another suitable material. For example, in certain non-limiting embodiments, the structure <NUM> can comprise 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 <NUM> into which the multi-piece fastener <NUM> is assembled comprises aluminum and/or an aluminum alloy, such as, for example, <NUM> aluminum alloy. With reference to the accompanying figures, in various non-limiting embodiments the structure <NUM> can be configured as at least one of an aerospace component or structure, an automotive component or structure, a transportation component or structure, a building and construction component or structure, or another component or structure.

The structure <NUM> can comprise a single layer of material or at least two layers of material. For example, as illustrated in <FIG>, the structure <NUM> can comprise a first layer 570a and a second layer 570b. The first layer 570a can be intermediate the second layer 570b and the fastening collar <NUM> when the fastening collar <NUM> is installed. In various non-limiting embodiments, the first layer 570a is adjacent to the fastening collar <NUM>.

The bore <NUM> can have a bore diameter, Øb. Additionally, to facilitate alignment of the multi-piece fastener <NUM> with the bore <NUM>, the second diameter, Ø<NUM>, of the shank <NUM> can be sized and configured to be less than the bore diameter, Øb, thereby allowing the second pin end <NUM> to be readily disposed into and through the bore <NUM>. In various non-limiting embodiments, the bore diameter, Øb, can be less than a diameter of the head portion <NUM> in order to inhibit the head portion <NUM> of the pin <NUM> from moving into the bore <NUM>.

As illustrated in <FIG>, the second pin end <NUM> of the pin <NUM> was positioned in alignment with the bore <NUM> on the second side <NUM> of the structure <NUM> before being inserted through the bore <NUM>. The fastening collar <NUM> has been positioned over the second pin end <NUM>, and the second pin end <NUM> has been inserted into and through the collar cavity <NUM> of the fastening collar <NUM>. The first collar end <NUM> of the fastening collar <NUM> has been positioned to contact the first layer 570a of the structure <NUM>. For example, the fastening collar <NUM> can be in forcible contact with the structure <NUM>, which can limit further axial movement of the fastening collar <NUM> relative to the pin <NUM> along the longitudinal axis of the multi-piece fastener <NUM>. In various non-limiting embodiments in which the pin <NUM> and the fastening collar <NUM> comprise threads, inserting the second pin end <NUM> into the collar cavity <NUM> of the fastening collar <NUM> may require rotation of at least one of the fastening collar <NUM> and the pin <NUM>.

Referring to <FIG>, the collet <NUM> of the fastening collar installation apparatus <NUM> has engaged the shank <NUM> of the pin <NUM> of the multi-piece fastener <NUM>. For example, the collet <NUM> was positioned over the pull region <NUM> of the multi-piece fastener <NUM> and retracted within the housing <NUM> of the fastening collar installation apparatus <NUM>, which has caused the collet <NUM> to forcibly contact the anvil <NUM> of the fastening collar installation apparatus <NUM>. Responsive to the contact between the anvil <NUM> and the collet <NUM>, the jaws 256a-c have closed around the pull region <NUM> and have forcibly contacted the pull region <NUM> of pin <NUM>. The forcible contact between the jaws 256a-c and the pull region <NUM> has mechanically deformed the pull region <NUM> to form an annular shoulder, a groove, a thread, and/or other feature on the pull region <NUM>, thereby engaging the collet <NUM> with the pin <NUM>.

Upon engagement, the collet <NUM> can apply an axial force to the pull region <NUM> of the pin <NUM>, which can decrease a gap, if present, between the first layer 570a and the second layer 570b of the structure <NUM> and create forcible contact between the fastening collar <NUM> and the structure <NUM>. For example, referring to <FIG>, the collet <NUM> has further retracted within the fastening collar installation apparatus <NUM> and moved the pin <NUM> due to the engagement between the pull region <NUM> and the collet <NUM>. As the collet <NUM> retracts within the housing <NUM> of the fastening collar installation apparatus <NUM>, the anvil <NUM> can contact the fastening collar <NUM>. After a predetermined force is achieved, the fastening collar <NUM> can be at least partially deformed responsive to the forcible contact between the anvil <NUM> and the fastening collar <NUM>. For example, the fastening collar <NUM> can be swaged onto a generally smooth region, a threaded region, an annular shoulder, a groove, and/or other feature on a section of the shank <NUM> intermediate the first layer 570a and the second pin end <NUM>. At least partially deforming the fastening collar <NUM> onto the shank <NUM> of the pin <NUM> can thereby secure the fastening collar <NUM> to the shank <NUM> and secure the multi-piece fastener <NUM> to at least a portion of the structure <NUM>. In that way, for example, the first layer 570a and second layer 570b of the structure <NUM> are secured together (e.g., inhibited from axial movement along the longitudinal axis of the multi-piece fastener <NUM>).

As illustrated in the non-limiting embodiment illustrated in <FIG>, after installation of the multi-piece fastener <NUM> into the structure <NUM>, the fastening collar <NUM> and the head portion <NUM> of the pin <NUM> are applying a clamping force to the layers 570a-b of the structure <NUM>, thereby securing the multi-piece fastener <NUM> to the structure <NUM> and securing layers 570a-b together. Additionally, an annular shoulder, a groove, a thread, and/or other feature has been formed on the pull region <NUM> of the pin <NUM> by the collet <NUM> of the fastening collar installation apparatus <NUM>, thus providing a visual indication that the multi-piece fastener <NUM> has been installed. In various non-limiting embodiments, as illustrated in <FIG>, the pin <NUM> may not fracture after installation into the structure <NUM>.

The present disclosure includes methods for installing a fastener and fastening a structure, as described and illustrated herein. In various non-limiting embodiments, referring to <FIG>, the multi-piece fastener systems according to the present disclosure can be used in a method for fastening a structure. A second end of a multi-piece fastener according to the present disclosure can be inserted into a bore in a structure, <NUM>. At least a portion of the second pin end can be passed through a collar cavity of a fastening collar of the multi-piece fastener according to the present disclosure, <NUM>. The pull region of the pin can be forcibly contacted with jaws of a collet of a fastening collar installation apparatus according to the present disclosure, <NUM>. An annular shoulder, a groove, a thread, and/or other feature can be formed on the pull region of the pin of the multi-piece fastener system according to the present disclosure by the jaws of the collet of the fastening collar installation apparatus according to the present disclosure, <NUM>. For example, the jaws of the collet of the fastening collar installation apparatus according to the present disclosure can apply a force to a surface of the pull region that is greater than a yield strength of the pull region.

The fastening collar can be forcibly contacted with an anvil of the fastening collar installation apparatus, <NUM>. The pull region can be moved distal from the fastening collar utilizing the collet of the fastening collar installation apparatus according to the present disclosure, <NUM>. Thereby, the fastening collar installation apparatus deforms the fastening collar onto the shank of the pin and secures at least a portion of the multi-piece fastener according to the present disclosure in the structure, <NUM>.

Claim 1:
A multi-piece fastener (<NUM>) comprising:
a fastening collar (<NUM>) comprising:
a first collar end (<NUM>); and
a second collar end (<NUM>),
wherein a collar cavity (<NUM>) extends from the first collar end to the second collar end; and
a pin (<NUM>) configured to be at least partially received by the collar cavity, the pin comprising
a first pin end (<NUM>) comprising a head portion (<NUM>);
a second pin end (<NUM>) comprising a pull region (<NUM>), wherein the pull region is generally cylindrical and smooth and is configured to form at least one of an annular shoulder, a groove, a thread, and other feature thereon responsive to forcible contact from a fastening collar installation apparatus (<NUM>); and
a shank (<NUM>) extending intermediate the first pin end and the second pin end, wherein the fastening collar is configured to be deformed onto the shank.