Amorphous metal rivet system

Abstract

To provide bucked-type rivets made at least partially of an amorphous metal alloy.SOLUTION: A bucked-type rivet assembly includes a formable member and an anvil. The anvil is configured to thermoplastically deform the formable member proximate to the second member by passing current through an electrical circuit that includes at least one of the formable member and anvil.SELECTED DRAWING: Figure 6

Description

Technical Field

[0002] , ,

[0004] ,

[0003] , , , , , , , , ,

[0005] ,

[0001] 〔Cross - Reference to Related Applications〕 This application claims the benefit and priority of U.S. Provisional Patent Application No. 62 / 735,225, filed on September 24, 2018, the entire disclosure of which is incorporated herein by reference.

Background Art

[0002] The present disclosure generally relates to the field of permanent mechanical fasteners. More specifically, the present disclosure relates to rivets conventionally used to secure two or more metal plates to each other. These include blind rivets applied from one side of a stack of workpieces to be joined, and standard rivets where their installation requires access to both sides of the stack of workpieces.

Summary of the Invention

Means for Solving the Problems

[0003] One embodiment relates to a blind rivet at least partially composed of an amorphous metal alloy. The blind rivet includes a head portion and a tail portion. The tail portion includes a first leg and a second leg. The tail portion further includes a tail interface disposed at each end of the first leg and the second leg. The head portion is configured to engage a first member. Each tail interface of the first leg and the second leg is configured to engage a second member. At least one of the first leg and the second leg is configured to elastically deform to fix the first member in a predetermined position relative to the second member.

[0004] In any of the above embodiments, the head portion may be configured to elastically deform when fixing the first member to the second member. In any of the above embodiments, the blind rivet may include a sleeve disposed near the tail interface, which can facilitate the installation of the blind rivet.

[0005] In some embodiments, the blind rivet may include a third leg and a fourth leg, both located on the head portion. The blind rivet may further include a tension member located near the third leg and the fourth leg, the tension member being configured to facilitate the installation of the blind rivet.

[0006] Another embodiment relates to a back-type rivet assembly. The back-type rivet assembly includes a formable member made of an amorphous metal alloy. An anvil, configured to facilitate the installation of the formable member, is at least partially positioned within a channel through the formable member. The anvil includes an interface shaft and an anvil head positioned at a first end of the interface shaft. The formable member is configured to fix the first member in place relative to a second member. The anvil head is configured to plastically deform the formable member in close proximity to the second member. The anvil head is further configured to separate from the interface shaft when a predetermined tension is applied to the interface shaft.

[0007] In some embodiments, the back-type rivet assembly may form an electrical circuit including at least one of an anvil and a moldable member.

[0008] In some embodiments, the moldable member can be heated by ultrasonically exciting an anvil or by rapidly rotating an anvil across one or more surfaces of the moldable member.

[0009] Another embodiment relates to a method for installing a back-type rivet. This method includes inserting a moldable member through a first opening in a first member and a second opening in a second member. This method also includes inserting an anvil into a channel in the moldable member. The anvil includes an interface shaft and an anvil head positioned at a first end of the interface shaft. The anvil further includes an insulating layer positioned on the outer surface of the interface shaft. This method further includes passing current through an electrical circuit including the interface shaft, the anvil head, and the moldable member. This method further includes pulling the interface shaft to deform a portion of the moldable member. This method also includes breaking the interface shaft.

[0010] This summary is for illustrative purposes only and is not intended to limit the scope of the invention. Other aspects of the apparatus and / or process described herein, features of the invention, and advantages, defined solely by the claims, will become apparent in the detailed description herein, together with the accompanying drawings, where similar reference numerals refer to similar elements. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a side view of a blind rivet in a cross-section passing through a plane parallel to the axis of the blind rivet, according to an exemplary embodiment. [Figure 2A] Figure 2A is a side view of a blind rivet with a deformable head portion, shown in a cross-section passing through a plane parallel to the axis of the rivet, according to an exemplary embodiment. [Figure 2B] Figure 2B is a side view of the blind rivet in Figure 2A that fastens a stack of workpieces together, according to an exemplary embodiment. [Figure 3A-3B]Figure 3A is a side view of a blind rivet according to an exemplary embodiment, showing a cross-section through a plane parallel to the axis of the blind rivet, and including deformable legs for both the head and tail portions of the blind rivet. Figure 3B is a side view of the blind rivet of Figure 3A, according to an exemplary embodiment, for fastening a stack of workpieces together. [Figure 4] Figure 4 is a side view of a blind rivet according to an exemplary embodiment, showing a cross-section through a plane parallel to the axis of the blind rivet, with a set of second barbs on the head portion of the blind rivet. [Figure 5] Figure 5 is a side view of a two-piece blind rivet in a cross-section passing through a plane parallel to the axis of the blind rivet, according to an exemplary embodiment. [Figure 6] Figure 6 shows a back-type rivet and a molded piece in a cross-section passing through a plane parallel to the axis of the back-type rivet, according to an exemplary embodiment. [Figures 7A-7B] Figure 7A is a side perspective view of the back-type rivet shown in Figure 6. Figure 7B is a side view of the molded piece shown in Figure 6. [Figure 8] Figure 8 is a side perspective view of an applicator device for back-type rivets according to an exemplary embodiment. [Figure 9] Figure 9 is a flowchart illustrating the outline of a method according to an exemplary embodiment. [Figure 10] Figure 10 is a side view of a back rivet, shown in a cross-section passing through a plane parallel to the back rivet, which fastens a stack of workpieces together, according to an exemplary embodiment. [Figure 11] Figure 11 is a side view of the back-type rivet of Figure 10 after the molded piece has been separated, according to an exemplary embodiment. [Modes for carrying out the invention]

[0012] Before moving on to the diagrams illustrating exemplary embodiments in detail, it should be understood that this disclosure is not limited to the details or methodologies described or shown in the description or diagrams. It should also be understood that the terms used herein are for illustrative purposes only and should not be considered limiting.

[0013] Traditionally, rivets are constructed from materials harder than those being joined. However, with the increasing use of high-strength alloys, finding suitable rivet materials has become a challenge. Many of the failure modes typically associated with riveted joints, such as excessive tensile stress, shear stress, and rivet pull-out from the joint, can be addressed by improving the material properties of the rivet and also by improving the mechanism of contact forces between the rivet and the workpiece being joined.

[0014] Generally, a family of rivets is provided, as shown in the diagram. Rivets are at least partially composed of amorphous metal alloys such as bulk metallic glass (BMG). Two types of rivets are provided, including elastic brad rivets (e.g., blind rivets inserted from one side of a stack of workpieces to be joined) and standard or back rivets that are fixed in place by plastically deforming at least one end of the rivet. The design of elastic brad rivets takes advantage of the inherent properties of BMG, a material that can withstand large amounts of elastic deformation, to fasten two or more workpieces (e.g., metal plates). Elastic brad rivets can be mechanically compressed and inserted into joining holes in workpieces. A series of barbed features at the tail end of each brad rivet unfold near the outer edge of the joining hole, locking the rivet in place. The elastic deformation of the tail end of each brad rivet results in tension that locks the workpieces together.

[0015] Each rivet in the family of back-type rivets disclosed herein is secured in place by thermoplastic deformation of a portion of the rivet on either one or both sides of a stack of workpieces. Therefore, the installation procedure generally requires access to both sides of the stack of workpieces to be joined. A rivet setter or other applicator device is used to facilitate the installation of each back-type rivet. For example, a rivet setter can generate an electric current flowing through the back-type metal generator (BMG) to rapidly heat the BMG while simultaneously applying force or pressure to thermoplastically deform a portion of the rivet. This particular back-type rivet design is useful for use with a gas or liquid supply system to rapidly cool the rivet after the forming process is complete.

[0016] A riveting tool can interface with the material or sacrificial part of the anvil to which force is transmitted to a back-type rivet. Instead of heating the material using electric current, the riveting tool can heat the material by rapidly rotating the anvil across the surface of the rivet, applying ultrasonic energy to the anvil, or by mechanically exciting the anvil. Further details of the general description provided above are explained more fully by referring to Figures 1 to 10.

[0017] Referring here to Figure 1, a blind rivet is provided, shown as a brad rivet 100. The brad rivet 100 is a permanent mechanical fastener configured to fasten two or more workpieces to each other in a predetermined position. The brad rivet 100 has a variety of applications. In one embodiment, the brad rivet 100 is used to fasten a series of metal plates to each other for a ship's hull. In another embodiment, the brad rivet 100 is used to fasten thin aluminum plates to each other in the construction of an aircraft cockpit and fuselage. The brad rivet 100 provides a viable alternative to welding and bolting, particularly for projects where the final weight of the joined workpieces is a critical consideration.

[0018] In an exemplary embodiment, the blind rivet 100 is configured to fix two workpieces (e.g., steel or aluminum plates, etc.) to each other within a stack shown as stack 110. In other embodiments, the number of workpieces to be joined may be more. Stack 110 includes a first member shown as first metal plate 112 and a second member shown as second metal plate 114, which are arranged in direct contact with each other. The thickness of each metal plate may vary depending on structural requirements. In the embodiment of FIG. 1, the thicknesses of metal plates 112 and 114 are substantially equal. As shown in FIG. 1, the blind rivet 100 is inserted through an opening 116 that extends through each of the first metal plate 112 and the second metal plate 114. In the embodiment of FIG. 1, the opening 116 includes a first opening 118 disposed in the first metal plate 112 and a second opening 120 disposed in the second metal plate 114. Both the first opening 118 and the second opening 120 are circular holes. The first opening 118 has a diameter larger than that of the second opening 120 to accommodate a sleeve 126 for the blind rivet 100. In other embodiments, the respective sizes and shapes of the first opening 118 and the second opening 120 may be different.

[0019] A variety of suitable amorphous metal alloys may be used for the blind rivet 100. In particular, amorphous metal alloys including BMG alloys and / or crystalline metals characterized by a very large elastic limit and high tensile strength can be used. Advantageously, BMG alloys with a large elastic limit (the upper limit of strain that an elastic material can be processed before breaking) enable the blind rivet 100 to be compressed into a small opening and deployed into a large state for maximum gripping / clamping / holding force. Suitable BMG alloys can have an elastic limit of strain of about 2% or more, which is about four times higher than that of typical crystalline metals. Among various alternatives, the amorphous metal alloy can include zirconium-based BMG alloys or nickel-based BMG alloys, both of which have low manufacturing costs. Alternatively, or additionally, it may be desirable to have a material with improved fatigue life to avoid breakage of the blind rivet 100 due to vibration or stress corrosion in more corrosive environments such as air or seawater.

[0020] In the exemplary embodiment shown in FIG. 1, the blind rivet 100 includes a head portion shown as a head 140 and a tail portion shown as a tail 160 disposed at an end opposite to the blind rivet 100. The blind rivet 100 further includes a shaft shown as a cylindrical extension 180 disposed between the head 140 and the tail 160. As shown in FIG. 1, the head 140 of the blind rivet 100 is formed in a dome shape having a planar lower surface shown as a flat lower surface 142 disposed in contact with the outer surface 124 of the first metal plate 112. In other embodiments, the shape of the head 140 may be different. For example, the head 140 can be in a rectangular shape with a uniform cross section. Alternatively, the head 140 can be circular with a uniform cross section or any other shape that properly interfaces with the first metal plate 112 and prevents the blind rivet 100 from passing through the first opening 118.

[0021] As shown in Figure 1, the tail 160 of the brad rivet 100 includes two legs, a first leg 162 and a second leg 164, which curve away from each other (for example, peeling towards the head 140 of the brad rivet 100). In the embodiment of Figure 1, the first and second legs 162, 164 are formed by dividing a cylindrical extension 180 along a plane oriented parallel to the longitudinal axis 102 of the brad rivet 100, resulting in legs 162, 164 each having a substantially semicircular cross-sectional shape. Other embodiments may include more legs, each having a similar cross-sectional area. Alternatively, one or more legs may be larger or smaller than the others.

[0022] According to an exemplary embodiment, each of the first leg 162 and the second leg 164 includes a tail interface, indicated as a barb 166, configured to engage with the second metal plate 114. Once installed, the barb 166 prevents the brad rivet 100 from being removed from either the first or second opening 118, 120. The barb 166 is a small projection extending outward from the longitudinal axis 102 of the brad rivet 100. For example, the barb can be a sharp tip, a ridge configured to dig into the material, a hook-shaped extension configured to grip or lock the outer edge of the material, or any combination thereof. During installation, the first and second legs 162, 164 are held in close proximity to each other and compressed by at least one of the first opening 118 and the second opening 120. Once the brad rivet 100 is inserted beyond a predetermined point, the first leg 162 and the second leg 164 unfold (for example, separate from each other) and latch onto the second metal plate 114 at a position close to the outer edge 122 of the second opening 120 (for example, just beyond the outer edge 122, or at another fixing point along the inner surface of the second opening 120). In the embodiment shown in Figure 1, the separation distance 168 between the first leg 162 and the second leg 164 increases as the head 140 of the brad rivet 100 approaches the outer surface 124 of the first metal plate 112.

[0023] The brad rivet 100 utilizes the high elastic limit of the BMG with a geometric shape that allows for compression, insertion through the joint opening, and fixation in place, due to the nature of the forces generated in the brad rivet 100. The brad rivet is shown in the installation position in Figure 1. In the embodiment of Figure 1, the elastic tension generated in the rivet is configured to fix the first member in place relative to the second member. When the first and second legs 162, 164 separate beyond the outer surface of the second metal plate 114, tension is generated in the brad rivet 100. This tension acts to prevent the first metal plate 112 and the second metal plate 114 from separating from each other and from separating from the head 140 of the brad rivet 100. Once the brad rivets 100 are fully installed, the compressive force acting on the first and second legs 162 and 164 decreases, but a compressive force remains that maintains the legs 162 and 164 in firm contact with the second metal plate 114, even when stress or vibration is applied to the joined workpiece.

[0024] Advantageously, the installation of the brad rivet 100 requires access to only one side of the stack 110. In exemplary embodiments, the brad rivet 100 is inserted into the first opening 118 by compressing each of the first legs 162 and the second legs 164 toward each other (for example toward the longitudinal axis 102 of the brad rivet 100), thereby reducing the separation distance 168 between the first leg 162 and the second leg 164 such that the outer diameter of the tail 160 is smaller than the inner diameter of the second opening 120. Various tools can be used to compress the first and second legs 162, 164. In embodiments of Figures 1 and 2A, the compressive force is applied by positioning sleeves 126, 226 around the tails 160, 260 of the brad rivet 100. Sleeves 126, 226 are devices configured to position legs 162, 164, 262, 264 before the installation of the brad rivets 100, 200. For example, the sleeves can be hollow cylinders, removable C-clips or fasteners, or a combination thereof. In Figures 1 and 2A, sleeves 126, 226 take the form of short hollow cylinders. As shown in Figure 2A, before inserting the brad rivet 200 into the first opening 118, sleeve 226 is positioned centered on the barb 266 such that the barb 266 contacts the inner surface 228 of sleeve 226. Alternatively, sleeve 226 may be positioned on a portion of the tail 260 just above the barb 266, in which case the barb portion of the tail 260 can be used to help center the brad rivet 200 for at least one of the first opening 118 and the second opening 120 before installation.

[0025] As shown in Figure 1, the sleeve 126 of the brad rivet 100 is configured to facilitate the installation of the brad rivet 100. In the embodiment of Figure 1, the diameter of the first opening 118, indicated as the first opening diameter 130, is larger than the diameter of the second opening 120, indicated as the second opening diameter 132. The sleeve 126 is configured to engage with the first opening 118. Furthermore, the sleeve 126 aligns the brad rivet 100 to the center of the first opening 118. In exemplary embodiments, the height of the sleeve 126 can be less than or equal to the thickness of the first metal plate 112 so that the sleeve 126 is fully inserted into the first opening 118. In other embodiments, the height of the sleeve 126 is greater than the thickness of the first metal plate 112 and is engaged with both the first opening 118 and the slot 134 of the second metal plate 114 (therefore aligning the brad rivet 100 to the center of the second opening 120). In yet another embodiment, the brad rivet 100 is installed without a sleeve 126. For example, the first opening diameter 130 can be sized to accommodate the curved edge 170 of the barb 166, and the curved edge 170 is configured to guide the first leg 162 and the second leg 164, respectively, toward the longitudinal axis 102 of the brad rivet 100 toward each other when the tail 160 enters the first opening 118.

[0026] In an exemplary embodiment, a drive tool (e.g., a hammer or other drive tool configured to push the tail 160 of the brad rivet 100 into the second opening 120) is used to fix the brad rivet 100 in place relative to the metal plates 112, 114. The method of installing the brad rivet 100 includes inserting the sleeve 126 into the first opening 118 and using a drive tool to push the tail 160 of the brad rivet 100 out of the sleeve 126 into the second opening 120 (e.g., by repeatedly bringing the head 140 of the brad rivet 100 into contact with the drive tool). During installation, the sleeve 126 remains fixed in place relative to the metal plates 112, 114. The installation of the brad rivet 100 is completed when the flat underside 142 of the head 140 contacts the first metal plate 112.

[0027] In exemplary embodiments (not shown), at least one of the first opening diameter 130 and the second opening diameter 132 may be larger than the outer diameter of the cylindrical extension 180 between the head 140 and tail 160 of the brad rivet 100. This additional space (e.g., a small annular gap between the brad rivet 100 and the workpiece to be joined) is at least partially accommodated by the large elastic displacement of the first and second legs 162, 164 of the brad rivet 100.

[0028] Figures 2A and 2B show exemplary embodiments of a brad rivet 200, including a head portion indicated as a head 240 configured to be elastically deformable. As shown in Figure 2A, the head 240 of the brad rivet 200 is formed in a dome shape with a flat bottom surface indicated as a flat bottom surface 242. The brad rivet 200 includes a first leg 262 and a second leg 264, which are a pair of legs positioned on the tail portion indicated as the tail 260 of the brad rivet 200. Before installation, as shown in Figure 2A, each of the first leg 262 and the second leg 264 is compressed against each other toward the longitudinal axis of the brad rivet 200 by a sleeve 226.

[0029] The method used to install the brad rivet 100 in Figure 1 can also be used to install the brad rivet 200 in Figure 2A. Figure 2B shows the same brad rivet 200 as in Figure 2A after joining the first metal plate 112 and the second metal plate 114. As shown in Figure 2B, the first leg 262 and the second leg 264 extend beyond the outer edge 122 of the second opening 120 (for example, separated from each other). The first leg 262 and the second leg 264 contact the outer edge 122 of the second opening 120, preventing the brad rivet 200 from being pulled back through the second opening 120.

[0030] In the embodiments of Figures 2A and 2B, some of the elastic tension generated within the brad rivet 200 is due to the deformation of the head 240. During installation of the brad rivet 200, as shown in Figure 2B, a portion of the head 240 elastically deforms, creating a recess in the head 240, indicated as a recess 268. As the head 240 returns to its original geometric shape (shown in Figure 2A), the metal plates 112 and 114 are joined together by the elastic tension generated in the brad rivet 200. In other words, the combined deformation of the head 240 and the first and second legs 162 and 164 generates elastic tension within the brad rivet 200 that compresses the metal plates 112 and 114 between the head 240 and the tail 260.

[0031] Further exemplary embodiments of the brad rivet 300 are shown in Figures 3A and 3B. As shown in Figure 3A, the brad rivet 300 includes a head 340 and a tail 360, each containing a set of deformable legs. The first legs 362 and the second legs 364 are positioned close to the tail 360 of the brad rivet 300, and the third legs 342 and the fourth legs 344 are positioned close to the head 340. Similar to the brad rivets 100, 200 in Figures 1, 2A, and 2B, each of the legs 362, 364, 342, and 344 includes an interface function configured to engage with the second metal plate 114. Each of the first leg 362 and the second leg 364 of the brad rivet 300 includes a tail interface, indicated as a tail barb 366, and each leg 342, 344 on the head 340 of the brad rivet 300 includes a head interface, indicated as a head barb 346. The brad rivet 300 also includes a tensile member, indicated as a fracture stem 348 (see Figure 3A), located in the center between the third leg 342 and the fourth leg 344. As shown in Figure 3A, the fracture stem 348 extends along the longitudinal axis 302 of the brad rivet 300 away from the tail 360 of the brad rivet 300.

[0032] The fracture stem 348 is configured to engage with an applicator device to facilitate the installation of the brad rivet 300. The method of installing the brad rivet 300 involves engaging each of the tail legs 366 with the second metal plate 114 adjacent to the outer edge 122 of the second metal plate 114. This can be achieved by first fixing a sleeve (not shown) along the length of the brad rivet 300, the sleeve 330 being configured to compress each of the legs 362, 364, 342, 344 toward the longitudinal axis 302 of the brad rivet 300. In an exemplary embodiment, the sleeve 330 is a hollow cylinder extending along the entire length of the brad rivet 300 (for example, a sleeve oriented so that the central axis of the sleeve is substantially parallel to the longitudinal axis 302). In an exemplary embodiment, the inner diameter of the sleeve is substantially the same as the first and second opening diameters 130, 132. This method includes aligning the central axis of the sleeve 330 with the central axis of the first opening 118 and directly discharging the brad rivet 300 from the sleeve 330 into the first and second openings 118 and 120.

[0033] The method further includes pulling back the fracture stem 348 that compresses the first leg 362 and the second leg 364 toward each other toward the longitudinal axis 302 of the brad rivet 300 (for example, away from the tail 360 of the brad rivet 300 in a direction perpendicular to the outer surface 124 of the first metal plate 112). The brad rivet 300 stretches as the separation distance 368 between the first leg 362 and the second leg 364 decreases. This process continues until each of the third leg 342 and the fourth leg 344 engages with the first metal plate 112 in proximity to the edge of the first metal plate 112, indicated as the upper edge 136. The method is terminated by separating the fracture stem 348 from the brad rivet 300 by bending, twisting, or by applying a predetermined force with an applicator device.

[0034] In the exemplary embodiment shown in Figure 4, the head interface of each leg 442, 444 of the brad rivet 400 includes multiple barbed features. As shown in Figure 4, the head interface further includes a second barbed head 450 positioned immediately below the barbed head 446 on the tail-facing side of the barbed head 446. Similar to the barbed head 446, the second barbed head 450 is a small projection extending away from either the third leg 442 or the fourth leg 444 in a direction substantially perpendicular to one of the third leg 442 and the fourth leg 444. The use of multiple barbed heads 446, 450 allows the brad rivet 400 to be tightened by distinct amounts during installation. Among the various advantages, the use of multiple barbed heads 446, 450 allows the design of a single brad rivet 400 to accommodate workpieces of varying thicknesses. The use of multiple head fins 446 and 450 also provides a mechanism for adjusting the tension that secures the workpieces together.

[0035] In various exemplary embodiments, the method of installing the brad rivets 300, 400 may differ. For example, in embodiments where the user is provided with access to both sides of the stack 110 of workpieces to be joined, moving the brad rivets 300, 400 from the sleeve to one of the first and second openings 118, 120 can be greatly simplified. Furthermore, the length and geometric shape of the sleeve can be modified according to the material properties and geometric shape of the brad rivets 300, 400.

[0036] Various shapes are possible for the head interface. In one embodiment, the head interface takes the form of a sawtooth pattern along the surfaces of the third and fourth legs, respectively. In other embodiments, the head interface is formed in the shape of a hook or other geometric shape configured to latch or engage with the first metal plate 112.

[0037] Additional exemplary embodiments of the brad rivet 500 are generally shown in Figure 5. Similarly, the brad rivet 500 includes a head portion, indicated as head 540, and a tail portion, indicated as tail 560, located at the opposite end of the brad rivet 500 as head 540. As shown in Figure 5, the head 540 and tail 560 are separate components that engage with each other via a threaded interface 572. Similar to the brad rivets 100, 200 in Figures 1, 2A, and 2B, the head 540 of the brad rivet 500 is formed in a dome shape with a planar bottom surface indicated as flat bottom surface 542. During installation, the flat bottom surface 542 contacts the outer surface 124 of the first metal plate 112. The threaded interface 572 includes a threaded extension 574 located in the center of the flat bottom surface 542 of the head 540. The threaded extension 574 is housed in a threaded hole 576 of the tail 560.

[0038] In the embodiment shown in Figure 5, both the tail 560 and head 540 of the brad rivet 500 are made of BMG, except the head is not configured to be elastically deformable. Alternatively, the head may be made of another material (e.g., a steel alloy). Similarly, the tail 560 includes a first leg 562 and a second leg 564 configured to be elastically deformable or unfold at the opposite end of the workpiece stack 110 when inserted into the opening 116. As shown in Figure 5, the tail 560 extends through the second opening 120 and a portion of the first opening 118. In other embodiments, the tail 560 extends only through a portion of the first opening 118.

[0039] Advantageously, the tension generated by the brad rivet 500 in Figure 5 can be easily adjusted after installation via the threaded interface 572. In exemplary embodiments, the head 540 may include a fastener interface configured to engage with a fastening tool. In one embodiment, the fastener interface is one of various types of screw drive devices (e.g., hexagonal, slot drive devices, etc.). In other embodiments, the head 540 is a hexagonal head cap screw or other types of bolts.

[0040] Figure 6 provides an exemplary embodiment of a back-type rivet assembly, indicated as rivet assembly 600. The rivet assembly 600 includes a formable member indicated as rivet piece 602 and an anvil indicated as molded piece 604. The molded piece 604 is configured to be housed within a channel 606 of rivet piece 602. Rivet piece 602 is shown separated from molded piece 604 in Figure 7A, while molded piece 604 is shown separated from rivet piece 602 in Figure 7B.

[0041] As shown in Figure 7A, the rivet piece 602 includes a head portion, indicated as a head 608, which is positioned at the first end of the shaft, indicated as a cylindrical extension 610. In exemplary embodiments, the rivet piece 602 is formed as a single piece from an amorphous metal alloy. Similar to the brad rivets shown in Figures 1, 2A–2B, and 5, the head 608 of the rivet piece 602 is formed in a dome shape with a flat bottom surface indicated as a flat bottom surface 612, which is configured to contact one of the first metal plate 112 and the second metal plate 114 (see also Figures 9–10). The cylindrical extension 610 of the rivet piece 602 has an outer diameter sized to fit both the first opening 118 and the second opening 120 simultaneously.

[0042] Various suitable amorphous metal alloys may be used for the rivet piece 602. Amorphous metal alloys with a moderately large thermoplastic processing window or supercooled liquid region are particularly attractive for this application. The supercooled liquid region (ΔTx) is defined as the separation (e.g., temperature difference) between the temperature (Tx) associated with the initiation of crystallization and the glass transition temperature (Tg). Suitable amorphous metal alloys may include BMG alloys having a subcooled liquid region ΔTx = Tx - Tg in the range of about 20°C to over 130°C. Other possible candidates include titanium, iron, and nickel-based BMG alloys. Yet another possible candidate is zirconium-based BMG, which can be alloyed with one or a combination of copper, nickel, titanium, aluminum, and beryllium. Zirconium BMG can also be alloyed with one or more Group 3 elements as small amounts of alloying additives such as yttrium and scandium to improve the feasibility of commercial-scale production.

[0043] In the embodiments of Figures 6 and 7B, the molded piece 604 is configured to be at least partially positioned in an opening, indicated as a channel 606, extending along the central axis of the rivet piece 602. As shown in Figure 7B, the molded piece 604 includes an interface shaft, indicated as a puller shaft 616, having a first end and a second end. The molded piece 604 also includes an anvil head, indicated as a molded head 618, positioned at the first end of the puller shaft 616. A portion of the puller shaft 616 is configured to separate from the molded piece 604 when a predetermined tension is applied to the puller shaft 616. The separation point, indicated as a notch 620, is located axially along the length of the puller shaft 616, close to the molded head 618. The notch 620 is configured to weaken the puller shaft 616 so that it breaks when a predetermined force is applied. The notch 620 can be any of a variety of different geometric shapes. For example, the notch 620 can be a V-shaped channel, a U-shaped channel, a rectangular channel, or any combination thereof. In the exemplary embodiments shown in Figures 6 and 7B, the notch 620 is a V-shaped channel extending around the puller shaft 616.

[0044] The molding head 618 is configured to plastically deform the tail 660 of the rivet piece 602. In an exemplary embodiment, the molding piece 604 is made of a conductive material having a larger cross-sectional area than the rivet piece 602 along the current path to reduce Joule heating within the molding piece 604. The molding piece 604 may also be made of a material having a higher melting point than the BMG to prevent the molding piece 604 from plastically deforming with and / or before the tail 660.

[0045] A variety of different materials, including steel and hard copper-beryllium alloys, can be used for molded slabs 604, both of which have higher conductivity than BMG. Suitable steel alloys can have conductivity of about 10% or more of the International Annealed Copper Standard (IACS), while suitable beryllium copper alloys can have conductivity in the range of 15-45% or more of IACS. These alloy families also both have relatively high thermal conductivity, which is necessary to quench BMG below its glass transition temperature (Tg) before devitrification can occur. Another example of a suitable material for molded slabs 604 is aluminum alloy. Among other advantages, aluminum alloys are less expensive and tend to have lower hardness, but have higher conductivity and thermal conductivity for more efficient and faster heating and cooling operations. Aluminum alloys are not as hard as copper or steel alloys, and above Tg, BMG alloys soften significantly and become viscous, leading to anvil wear and deformation over time, but aluminum-based molded slabs 604 can be a more economical solution in some implementations. More complex designs of the molded piece 604 are also feasible to supply current more efficiently to the BMG. For example, a highly conductive path (such as a wire) can be incorporated into pockets and / or openings placed in the molded piece, allowing current to be transmitted directly to the surface of the rivet instead of requiring current to flow through the molded piece 604 for heating. The highly conductive path may be insulated from the molded piece 604. Alternatively, the molded piece 604 may be configured such that some of the current flows through the molded piece 604 while some of the current flows through the highly conductive path.

[0046] The forming head 618 in Figures 6 and 7B is formed in a U-shape when viewed in cross-section, with its end curving toward the puller shaft 616. In other embodiments, the forming head 618 may be formed in a T-shape when viewed in cross-section (see Figures 9-10), or in other shapes that appropriately form the rivet piece 602 around the outer edge 122 of the second opening 120. As shown in Figure 6, the second end of the puller shaft 616 opposite the forming head 618 is configured to be housed within the channel 606. As shown in Figure 6, the second end of the puller shaft 616 extends beyond the head 608 of the rivet piece 602 along the central axis of the rivet piece 602 and is configured to be housed within an applicator device indicated as a rivet fastening tool 622 (see Figure 8).

[0047] A flowchart of a method 900 for installing a rivet assembly according to an exemplary embodiment is shown in Figure 9. The rivet assembly may be identical or similar to the rivet assembly 600 described with reference to Figures 6 to 8. For simplicity, similar numbering is used to identify similar components. Method 900 is conceptually shown in Figures 10 and 11. Method 900 includes, in 902, inserting the cylindrical extension 610 of the rivet piece 602 into the first opening 118 and the second opening 120 such that the flat lower surface 612 of the head 608 contacts the outer surface 124 of the first metal plate 112. Method 900 further includes, in 904, inserting the forming piece 604 into the channel 606 of the rivet piece 602 from the opposite side of the stack 110 (for example, from the second metal plate 114 toward the first metal plate 112) such that the forming head 618 contacts the cylindrical extension 610.

[0048] Various techniques can be used to deform the rivet piece 602 using the molded piece 604. For example, the rivet piece 602 may be heated to a molding temperature based on its size and material composition, and then deformed using the molded piece 604. To heat the rivet piece 602, the riveting tool 622 (see Figure 8) may incorporate a resistance heater or other suitable heating device. Alternatively, the riveting tool 622 may be configured to rapidly excite the molded piece 604 while in contact with the rivet piece 602. For example, the riveting tool 622 may be configured to excite the molded piece 604 using ultrasonic energy. Alternatively, the riveting tool 622 may be configured to rapidly rotate the molded piece 604 to generate heat at the interface between the molded piece 604 and the rivet piece 602.

[0049] In the exemplary embodiments shown in Figures 9 to 11, the rivet piece 602 is heated by passing current through an electrical circuit in 906 that includes a puller shaft 616, a molding head 618, and the rivet piece 602, arranged in series. The electrical circuit is completed by a rivet setting tool 622 (see Figure 8) that contacts both the puller shaft 616 and the head 608 of the rivet piece 602. As shown in Figures 10 to 11, the puller shaft 616 is separated from the rivet piece 602 by an annular gap 624 and an insulating layer, indicated as layer 626, which is located on the surface of the molding piece, indicated as the cylindrical outer surface 628. Layer 626 prevents the electrical circuit from short-circuiting across the annular gap between the molding piece 604 and the rivet piece 602 during the heating stage.

[0050] In method 900 shown in Figure 9, the rivet fastening tool 622 (see Figure 8) is configured in 908 to pull the second end of the rivet piece 604 while simultaneously passing current through the electrical circuit. Among other advantages, the method of heating the rivet piece 602 using current is fast and controllable and heats the rivet piece 602 directly rather than indirectly. Once heated, the rivet piece 602 begins to deform thermoplastically near the interface between the rivet piece 602 and the forming head 618, compressing the metal plates 112 and 114 to each other. Method 900 further includes breaking the interface shaft in 910. As shown in Figure 11, the notch 620 of the puller shaft 616 is sized such that the forming head 618 separates from the puller shaft 616 under a known load. The rivet piece 604 is then removed from the rivet assembly 600, leaving the rivet piece 602 behind. In the embodiments shown in Figures 10-11, the current is turned off to allow the rivet piece 602 to cool to a hardened, fully amorphous state before or during the separation of the molding head 618 from the puller shaft 616.

[0051] To assist in quenching the rivet piece 602 after the heating phase, a gas or liquid delivery system (not shown) can be coupled to the riveting tool 622. Among other advantages, quenching prevents devitrification of BMG during the cooling phase. The riveting tool 622 may be configured to provide and circulate a flow of gas (e.g., nitrogen, inert gas, etc.) or liquid (e.g., water) through the annular gap 624 between the molded piece 604 and the rivet piece 602. The riveting tool 622 may be configured to administer the gas or liquid by starting approximately simultaneously with or immediately before the current is turned off, thereby shortening the overall duration of the installation process.

[0052] In exemplary embodiments, the rivet piece 602 can be configured to deform thermoplastically on both sides of the stack 110 to achieve a very low profile of the rivet piece 602 on either side of the stack 110. For example, in exemplary embodiments, the rivet piece 602 is a shaft (e.g., a solid shaft with substantially the same geometric shape as the opening 116) that is deformed by positioning forming heads on the rivet pieces 602 on both sides of the stack 110 (e.g., positioning a first forming head of the first forming piece on the rivet piece 602 adjacent to the second metal plate 114, and a second forming head of the second forming piece on the rivet piece 602 adjacent to the first metal plate 112). Among other advantages, forming the rivet piece 602 from both sides forms a joint with the smallest possible gap (e.g., a tight seal) between the rivet piece 602 and both metal plates 112, 114. Furthermore, unlike conventional steel rivets, whose microstructure is altered during the molding process, heated BMG can be easily molded into various shapes without altering the material properties of the BMG (e.g., strength).

[0053] Back-type rivets composed of BMG can be formed into one of a variety of different shapes and sizes. In exemplary embodiments (not shown), at least one of the first and second openings 118, 120 has an irregular cross-sectional shape (e.g., square, elliptical, T-shaped, cruciate, or a larger opening of any shape). The back-type rivet may also be irregular in shape to conform to the geometric shape of the resulting opening 116 before forming, resulting in improved contact dynamics between the back-type rivet and the workpieces (e.g., metal plates 112, 114) being joined. Alternatively, the back-type rivet may take the form of two separate rivet plates. The rivet plates are positioned on both sides of the stack 110. Heat and pressure are applied to each rivet plate from both sides of the stack 110 to form the rivet plates integrally through any opening between the workpieces. Such a configuration is particularly beneficial when a tight seal along the joint is desired.

[0054] Where used herein, the terms “approximately,” “about,” “substantially,” and similar terms are intended to have a broad meaning consistent with the usage generally accepted by those skilled in the art relating to this disclosure. Those skilled in the art examining this disclosure should understand that these terms are intended to enable the description of specific features described and claimed without limiting the scope of those features to the exact numerical range provided. Accordingly, these terms should be construed as indicating that any substantial or insignificant modification or substitution of the subject matter described and claimed is deemed to fall within the scope of the disclosure as described in the appended claims.

[0055] As used herein, the term “coupled” means joining two members directly or indirectly to one another. Such a joining can be static (e.g., permanent or fixed) or movable (e.g., removable or detachable). Such a joining can be achieved by directly joining two members to one another, by joining two members to one another by separate intervening members and any additional intermediate members, or by joining two members to one another by an intervening member formed integrally with one of the two members as a single unit. Such members may be coupled mechanically, electrically, and / or fluidly.

[0056] Where used herein, the term “or” is used in its inclusive (not exclusive) sense, so that when used to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Conjunctions such as “at least one of X, Y, and Z” are understood, unless otherwise specified, to convey that the elements can be any of X, Y, and Z; X and Y; X and Z; Y and Z; or X, Y, and Z (i.e., any combination of X, Y, and Z). Thus, such conjunctions are not generally intended to imply, unless otherwise specified, that a particular embodiment requires at least one of X, at least one of Y, and at least one of Z to exist, respectively. stomach.

[0057] References to the position of elements in this specification (e.g., “top,” “bottom,” “above,” “below,” etc.) are used simply to describe the orientation of various elements in the drawings. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and such variations are intended to be included in this disclosure.

[0058] The drawings and descriptions may illustrate a specific order of method steps, but such an order of steps may differ from the order illustrated and described above unless otherwise specified. Also, unless otherwise specified above, two or more steps may be performed simultaneously or partially in parallel. Such variations may depend, for example, on the selected software and hardware systems and the designer's choice. All such variations are within the scope of this disclosure. Similarly, software implementations of the described methods can be achieved by standard programming techniques with rule-based logic and other logic for achieving various connection steps, processing steps, comparison steps, and decision steps. [Explanation of symbols]

[0059] 100 Bloodrivets 102 Longitudinal axis 110 stacks 112 First metal plate 114 Second metal plate 116 Aperture 118 First opening 120 Second opening 122 Outer edge 124 Exterior 126 sleeves 130 First aperture diameter 132 Second aperture diameter 134 slots 136 Upper edge 140 heads 142 Flat bottom surface 160 Tail 162 First leg 164 Second leg 166 Kaeshi 168 separation distance 170 Curved edge 180 Cylindrical extension 200 Blood Rivets 226 sleeves 228 Inner Self 240 heads 242 Flat bottom surface 260 Tail 262 First leg 264 Second leg 266 Kaeshi 268 indentation 300 Blood Rivets 302 Longitudinal axis 330 sleeves 340 heads 342 Third Leg 344 The fourth leg 346 Head Return 348 Fractured stem 360 Tail 362 First leg 364 Second leg 366 Tail flip 368 separation distance 400 Blood Rivets 442 Third Leg 444 The fourth leg 446 Head Return 450 Second Head Return 500 Blood Rivets 540 heads 542 Flat bottom surface 560 Tail 562 First leg 564 Second leg 572 Screw-type interface 574 Screw-on extension 576 screw holes 600 Rivet Assembly 602 Rivet pieces 604 Molded piece 606 channels 608 head 610 Cylindrical extension 612 Flat bottom surface 616 Puller Shaft 618 Molding Head 620 Notches 622 Rivet fastening tool 624 Annular gap 626 layers 628 Cylindrical outer surface 660 Tail 900 ways

Claims

1. 1. A back-type rivet assembly comprising: a formable member comprising an amorphous metal alloy and having a channel; an anvil at least partially disposed within the channel; The anvil an interface shaft; an anvil head disposed on a first end of the interface shaft; Equipped with the moldable member is configured to secure a first member in a predetermined position relative to a second member; the anvil head is configured to plastically deform the formable member adjacent the second member; A back-type rivet assembly, wherein the anvil head is configured to separate from the interface shaft when a predetermined tension is applied to the interface shaft.

2. The back-type rivet assembly of claim 1 , wherein the amorphous metal alloy comprises a BMG alloy.

3. 3. The back-type rivet assembly of claim 2, wherein the BMG alloy is characterized by a supercooled liquid region ΔTx=Tx-Tg in the range of 20°C to 130°C or higher.

4. 4. A back-type rivet assembly according to any one of claims 1 to 3, wherein the amorphous metal alloy comprises zirconium alloyed with at least one of yttrium or scandium.

5. 5. The back-type rivet assembly according to claim 1, wherein the moldable member includes a cylindrical extension having the channel and a head disposed at an end of the cylindrical extension.

6. The back-type rivet assembly of claim 5, wherein the head portion is formed in a dome shape having a generally flat lower surface that contacts the cylindrical extension portion.

7. 7. The back-type rivet assembly of claim 1, further comprising an insulating layer disposed in a gap formed between the anvil and the formable member, the anvil being constructed from an electrically conductive material, and the anvil head being electrically connected to the formable member.

8. 8. The back-type rivet assembly of claim 1, further comprising an annular gap between the formable member and the anvil, the annular gap configured to contain one of a gas and a liquid for cooling the formable member.

9. The back-type rivet assembly of claim 1 , wherein the formable member is plastically deformed by one of rapidly rotating the anvil and applying ultrasonic energy to the anvil.

10. 10. The back-type rivet assembly of claim 1, wherein the periphery of the formable member is formed to generally match the periphery of one of the first opening in the first member and the second opening in the second member.

11. 11. The back-type rivet assembly of claim 1, wherein the anvil is made of an electrically conductive material, and the cross-sectional area of ​​the interface shaft is greater than the cross-sectional area of ​​the portion of the formable member that surrounds the interface shaft.

12. 12. The back-type rivet assembly of any one of claims 1 to 11, wherein the anvil is made from one of: (i) a steel alloy having a conductivity of about 10% or greater of the International Annealed Copper Standard (IACS); or (ii) a beryllium copper alloy having a conductivity in the range of 15-45% IACS or greater.

13. The back-type rivet assembly of any one of claims 1 to 12, wherein the anvil further comprises a highly conductive pathway disposed within the interface shaft.

14. The back rivet assembly of claim 13, wherein the interface shaft has an opening and the highly conductive pathway includes a wire disposed within the opening.

15. 15. The back-type rivet assembly of any one of claims 1 to 14, wherein the interface shaft includes a notch located at an axial position adjacent the anvil head and extending around the circumference of the interface shaft.

16. 16. A back-type rivet assembly according to any one of claims 1 to 15, wherein the anvil head is formed in one of a U-shape or a T-shape when viewed in cross section.

17. 1. A method of setting a back-type rivet, comprising: Inserting a moldable member through a first opening in the first member and a second opening in the second member; inserting an anvil including an interface shaft, an anvil head disposed on a first end of the interface shaft, and an insulating layer disposed on an outer surface of the interface shaft into a channel of the moldable member; passing an electric current through an electrical circuit comprising the interface shaft, the anvil head, and the formable member; pulling the interface shaft to deform a portion of the moldable member; Destroying the interface shaft. A method comprising:

18. 18. The method of claim 17, further comprising passing a gas or liquid through an annular gap between the formable member and the anvil.

19. 19. The method of claim 17 or 18, wherein pulling the interface shaft comprises applying a force to the interface shaft while simultaneously passing a current through the electrical circuit.

20. 20. The method of any one of claims 17 to 19, further comprising contacting a riveting tool with the interface shaft and a head of the formable member to form the electrical circuit including the interface shaft, the anvil head, and the formable member.

Images