Core bolt, fastener system and method for connecting plurality of substrates of workpiece having working side and blind side

Abstract

The invention relates to a core bolt, a fastener system and a method for connecting a plurality of substrates of a workpiece having a working side and a blind side. A core bolt for a fastener system for connecting a plurality of substrates of a workpiece having a working side and a blind side is provided. The core bolt includes a head, a handle, and a removable drive element. The head includes a recessed torsion feature. The handle is opposite the recessed torsion feature and extends from the head along the longitudinal axis to a distal end. The handle includes a threaded portion between the distal end and the head. A releasable drive element extends from the recessed torsion feature and protrudes outwardly along the longitudinal axis to define a proximal end. A fastener system for connecting a plurality of substrates of a workpiece includes a nut member and a core bolt. A method for connecting a plurality of substrates of a workpiece having a working side and a blind side is also provided.

Description

Technical Field

[0001] The present disclosure relates generally to blind fastener systems and, in particular, to core bolts for use in such systems and methods for connecting multiple substrates of a workpiece having a working side and a blind side. Background Art

[0002] Future aircraft wing box structures are becoming increasingly smaller, creating limited space and the need for different fastening systems that can be assembled from the wing's outer mold line (e.g., skin / shear ties and skin / spar). Traditional fasteners with external pull features require a torque wrench for installation and break flush with the fastener head. Furthermore, these fasteners cannot be removed after installation without drilling through the fastener head.

[0003] Therefore, those skilled in the art are continually conducting research and development efforts to improve single-sided fastener systems for connecting multiple substrates. Summary of the Invention

[0004] This application discloses examples of core bolts, fastener systems, and methods for connecting multiple base plates of a workpiece having a working side and a blind side.The following is a non-exhaustive list of examples according to the disclosed subject matter, which may or may not be claimed.

[0005] In one embodiment, a core bolt of a fastener system for connecting multiple substrates of a workpiece having a working side and a blind side is disclosed. The disclosed core bolt includes a head, a shank portion, and a frangible drive element. The head includes a recessed torsion feature. The shank portion extends axially from the head along a central longitudinal axis to a distal end of the core bolt. The shank portion includes a threaded portion between the distal end and the head. The frangible drive element extends from the recessed torsion feature of the head and protrudes outwardly along the central longitudinal axis to define a proximal end of the core bolt.

[0006] In one embodiment, a fastener system for connecting multiple substrates of a workpiece having a working side and a blind side is disclosed. The disclosed fastener system includes a nut member and a core bolt. The nut member includes a nut hole having an internal thread. The core bolt includes a head, a shank, and a frangible drive element. The head includes a recessed torque feature. The shank extends axially from the head along a central longitudinal axis to a distal end of the core bolt. The shank includes a threaded portion between the distal end and the head. The frangible drive element extends from the head and projects outwardly along the central longitudinal axis to define a proximal end of the core bolt.

[0007] In one embodiment, a method for connecting a plurality of substrates of a workpiece having a working side and a blind side is disclosed. The disclosed method includes: (i) securing a nut member to a connection hole passing through the plurality of substrates on the blind side of the workpiece, the nut member including a nut hole having an internal thread; (ii) inserting a core bolt into the connection hole from the working side of the workpiece until a distal end of the core bolt contacts the nut member, the core bolt including a head having a concave torsion feature and a shank extending axially from the head along a central longitudinal axis to a distal end of the core bolt, the shank including a threaded portion between the distal end and the head, the core bolt further including a frangible drive element extending from the head and protruding outwardly along the central longitudinal axis to define a proximal end of the core bolt; (iv) rotating the core bolt to engage the threaded portion with the internal thread of the nut member; and (v) further rotating the core bolt to further engage with the nut member until the frangible drive element is separated from the core bolt to achieve installation.

[0008] Other examples of the disclosed core bolt, fastener system, and method for connecting multiple base plates of a workpiece having a working side and a blind side will become apparent from the following detailed description, the accompanying drawings, and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A is a side view of an example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side;

[0010] Figure 1B yes Figure 1A Top view of the core bolt;

[0011] Figure 1C yes Figure 1A A close-up side view of an example of the interface between the frangible drive element and the head of a core bolt;

[0012] Figure 2A After the easily removable drive element is separated from the core head Figure 1A A side view of the core bolt;

[0013] Figure 2B After the frangible drive element is separated Figure 1A Top view of the core bolt;

[0014] Figure 2C After being separated from the head Figure 1A A side view of an example of a frangible drive element;

[0015] Figure 3A is a side view of another example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side;

[0016] Figure 3Bis a side view of yet another example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side;

[0017] Figure 4A is a side view of yet another example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side;

[0018] Figure 4B yes Figure 4A Top view of the core bolt;

[0019] Figure 5A After the core bolt is easily disassembled and the drive element is separated from the core head Figure 4A A side view of the core bolt;

[0020] Figure 5B yes Figure 4A A top view of the core bolt showing the core head after the frangible drive element is separated;

[0021] Figure 5C After being separated from the head Figure 4A A side view of an example of a frangible drive element;

[0022] Figure 6 is a cross-sectional side view of an example of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side;

[0023] Figure 7A is a cross-sectional side view of an example of a connecting hole through multiple base plates of a workpiece, wherein the hole has a pointed bottom counterbore on the working side;

[0024] Figure 7B is a cross-sectional side view of another example of a connecting hole through multiple base plates of a workpiece, wherein the hole has a flat bottom counterbore on the working side;

[0025] Figure 7C is a cross-sectional side view of yet another example of a connection hole through a plurality of substrates of a workpiece;

[0026] Figure 8 is a cross-sectional side view of another example of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side;

[0027] Figure 9 is a flow chart of an example of a method for connecting multiple substrates of a workpiece having a working side and a blind side;

[0028] Figure 10 yes Figure 9 A flowchart of an example of fixing a nut member;

[0029] Figure 11 yes Figure 9A flowchart of an example of rotation of a core bolt and further rotation of the core bolt;

[0030] Figure 12 yes Figure 9 A flowchart of other examples of rotation of the core bolt and further rotation of the core bolt;

[0031] Figure 13 yes Figure 9 A flowchart of yet other examples of rotation of the core bolt and further rotation of the core bolt;

[0032] Figure 14 , combined with Figure 9 , is a flow chart of another example of a method for connecting multiple substrates of a workpiece having a working side and a blind side;

[0033] Figure 15 , combined with Figure 9 , is a flow chart of yet another example of a method for connecting a plurality of substrates of a workpiece having a working side and a blind side;

[0034] Figure 16 is a block diagram of an aircraft production and service method that implements one or more examples of the method disclosed herein for connecting multiple substrates of a workpiece having a working side and a blind side; and

[0035] Figure 17 is a schematic diagram of an aircraft including a workpiece having a plurality of base plates connected using one or more of the examples of the core bolt assembly, blind fastener system, and method disclosed herein for connecting a plurality of base plates of a workpiece having a working side and a blind side. DETAILED DESCRIPTION

[0036] Various examples of core bolts, fastener systems, and methods disclosed herein for connecting multiple substrates of workpieces having a working side and a blind side provide fasteners having a recessed head and a frangible drive element that breaks away sub-flush with the fastener head so that the fastener can be manually removed with a torque wrench, thereby enabling a single-sided removable bolt. The present disclosure relates to fastening systems that combine a torque break-off external wrench / drive element and a broached (head-side) recess in the same fastener. The external drive feature protrudes from the recess and breaks away sub-flush with the top of the fastener after initial installation. This allows the recess to be used to remove the fastener after the drive feature is removed.

[0037] No flushness shave is required after installation. The external wrench / drive element feature enables automated fastener installation without calibrated torque tools. The broached (head-side) recess allows the fastener to be removed after installation for rework or repair.

[0038] Various examples of core bolts with external drive elements allow the fastener to be torqued to a predetermined amount. When the predetermined torque is reached, the external drive element disconnects. Various examples of core bolts also include broached recesses so that the fastener can be removed after installation.

[0039] Various examples of the disclosed core bolts, fastener systems, and methods for connecting multiple baseplates having workpieces with working and blind sides include a broach drive element and an external pull feature that breaks at a desired load. This combines the benefits of both types of features in the same fastener. Taken individually, these features have certain disadvantages. For example, the broached recessed fastener type requires a torque wrench for installation. Whereas, the external pull feature that shears / breaks at a predetermined load leaves a bolt that cannot be easily removed after installation. For example, the remaining bolt must be drilled through or the head must be sheared off.

[0040] Overall reference Figure 1A -C, 2A-C, 3A-B, 4A-B, 6 and 7A-C, as examples, the present disclosure relates to core bolts 100, 400 of a fastener system 600, 800 for connecting multiple base plates 602 of a workpiece 604 having a working side 606 and a blind side 608. Figure 1A An example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 1B Shows Figure 1A view of a core bolt. Figure 1C Shows Figure 1A An example of the interface between the frangible drive element and the head of a core bolt. Figure 2A Shown after the frangible drive element is separated from the core head Figure 1A Side view of the core bolt. Figure 2B Shown after separation of the frangible drive element Figure 1A view of a core bolt. Figure 2C Shown after being separated from the head Figure 1A Example of a removable drive element. Figure 3A Another example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 3B Yet another example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 4AYet another example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 4B Shows Figure 4A view of a core bolt. Figure 6 An example of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 7A An example of connecting holes through multiple substrates of a workpiece is shown, with a pointed bottom countersunk hole on the working side. Figure 7B Another example of a connecting hole through multiple base plates of a workpiece is shown, with a flat bottom counterbore on the working side. Figure 7C Yet another example of connecting holes through multiple substrates of a workpiece is shown.

[0041] Refer again Figure 1A In one or more examples, a core bolt 100, 400 of a fastener system 600, 800 for connecting a plurality of substrates 602 having a workpiece 604 with a working side 606 and a blind side 608 is disclosed. The core bolt includes a head 106, a shank 108, and a frangible drive element 112, 412. The head 106 includes a recessed torsion feature 202. The shank 108 extends axially from the head 106 along a central longitudinal axis 110 to a distal end 104 of the core bolt 100, 400. The shank 108 includes a threaded portion 102 between the distal end 104 and the head 106. The frangible drive element 112, 412 extends from the recessed torsion feature 202 of the head 106 and projects outwardly along the central longitudinal axis 110 to define a proximal end 114 of the core bolt 100, 400.

[0042] In another example of the core bolt 100, 400, the core bolt 100, 400 comprises a metal material. In a further example, the metal material comprises stainless steel, titanium, a titanium alloy, a cobalt-chromium alloy, a nickel-titanium alloy, or any other suitable metal material (in any suitable combination). In yet another example of the core bolt 100, 400, the head 106 comprises a flush head, a countersunk head, a protruding head, a raised head, or any other suitable type of head (in any suitable combination). In yet another example of the core bolt 100, 400, the recessed torque feature 202 of the head 106 includes a recessed offset cruciform drive feature, a recessed dovetail drive feature, a recessed cross-tip drive feature, a recessed hexagon key drive feature, a recessed flat tip drive feature, or any other suitable type of recessed torque feature (in any suitable combination).

[0043] In yet another example of the core bolt 100, 400, after the frangible drive element 112, 412 is separated from the head 106, the recessed torque feature 202 of the head 106 facilitates rotating the core bolt 100, 400 using an offset cross-drive torque tool, a dovetail drive torque tool, a crosshead drive torque tool, an allen key torque tool, a flat-head drive torque tool, or any other suitable tool in any suitable combination. In another example of the core bolt 100, 400, the shank 108 is opposite the recessed torque feature 202 of the head 106. In yet another example of the core bolt 100, 400, the shank 108 includes a cylindrical body 302, a frustoconical body 304, or any other suitable shaped body (in any suitable combination). In yet another example of the core bolt 100, 400, the frangible drive element 112, 412 extends from the head 106 at the central base region 116 of the recessed torsion feature 202 and is configured to be engaged by a tool to install the core bolt 100, 400. In further examples, the tool includes an end effector on a robotic arm, a handheld power tool, a hand tool, or any other suitable tool (in any suitable combination).

[0044] In another further example, the frangible drive element 112 , 412 is separable from the head 106 at the central base region 116 of the recessed torsion feature 202 in response to a predetermined torque being applied by a tool during installation of the core bolt 100 , 400 . In yet a further example, the predetermined torque is based at least in part on the diameter of the core bolt 100, 400, the surface coating on the internal thread 614 of the nut member 610 into which the core bolt 100, 400 is to be installed, the friction level of the internal thread 614 of the nut member 610, the friction level between the shank 108 of the core bolt 100, 400 and the through-connecting holes 702 of the plurality of substrates 602 into which the core bolt 100, 400 is to be installed, the friction level between the shank 108 of the core bolt 100, 400 and the sleeve member 802 into which the core bolt 100, 400 is to be inserted, the effect of lubricant on the friction experienced by the core bolt 100, 400 during installation, the preload tension at the proximal end 114 of the frangible drive element 112, 412 within the core bolt 100, 400, or any other suitable feature of the fastener system (in any suitable combination).

[0045] In yet another example of the core bolt 100, 400, the frangible drive element 112, 412 includes an interface portion 118, 418, a torsion portion 120, 420, and a shank portion 124, 424. The interface portion 118, 418 extends from the head 106 and protrudes outwardly. The torsion portion 120, 420 includes a rotation feature 122, 422 at the proximal end 114 of the core bolt 100, 400. The shank portion 124, 424 extends axially along the central longitudinal axis 110 of the core bolt 100, 400 between the interface portion 118, 418 and the torsion portion 120, 420. In a further example, the interface portion 118, 418 of the frangible drive element 112, 412 extends from the head 106 at the central base region 116 of the recessed torsion feature 202.

[0046] In another further example, the rotational features 122, 422 of the torsional portion 120, 420 include a recessed spline drive feature, a recessed star drive feature, a recessed square-lobed star drive feature, a recessed 6-point star drive feature, a recessed 6-point square-lobed star drive feature, an opposing flat surface head feature, a recessed hexagon key drive feature, a hexagon head feature, a recessed cross-tip drive feature, a recessed flat tip drive feature, or any other suitable rotational features (in any suitable combination).In yet another further example, the rotation features 122, 422 of the torsion portion 120, 420 facilitate rotating the core bolt 100, 400 using a spline drive torquing tool, a star drive torquing tool, a square-lobed stardrive torquing tool, a 6-point star drive torquing tool, a 6-point square-lobed star drive torquing tool, an opposing flat surface socket torquing tool, a hexagon key torquing tool, a hexagon socket torquing tool, a cross-tip drive torquing tool, a flat tip drive torquing tool, or any other suitable tool in any suitable combination.

[0047] In yet another further example, the stem portion 124, 424 opposes the rotational feature 122, 422 of the torsion portion 120, 420. In yet another further example, the stem portion 124, 424 comprises an elongated cylindrical shape, an elongated hexagonal shape, an elongated multi-faceted shape, or any other suitable shape (in any suitable combination). In another further example of the frangible drive element 112, 412, the interface portion 118, 418 defines a breakneck groove 126 disposed near the head 106 at the central base region 116 of the recessed torsion feature 202 to facilitate separation of the frangible drive element 112, 412 from the core bolt 100, 400 in response to a predetermined torque being applied to the torsion portion 120, 420 during installation of the core bolt 100, 400.

[0048] In yet another example of the frangible drive element 112, 412, the interface portion 118, 418 includes an interface body 204 that tapers from a shank 124, 424 to a head 106 at a central base region 116 of the recessed torsion feature 202 to facilitate separation of the frangible drive element 112, 412 from the core bolt 100, 400 in response to a predetermined torque being applied at the torsion portion 120, 420 during installation of the core bolt 100, 400. In yet another example of the frangible drive element 112, 412, the interface body 204 defines a break neck groove 126 disposed proximate to the head 106 at the central base region 116 of the recessed torsion feature 202 to further facilitate separation of the frangible drive element 112, 412 from the core bolt 100, 400 in response to a predetermined torque being applied at the torsion portion 120, 420 during installation of the core bolt 100, 400.

[0049] Overall reference Figure 1A -C, 2A-C, 3A-B, 4A-B, 6, 7A-C, and 8, as examples, the present disclosure relates to fastener systems 600, 800 for connecting multiple base plates 602 of a workpiece 604 having a working side 606 and a blind side 608. Figure 1A An example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 1B Shows Figure 1A view of a core bolt. Figure 1C Shows Figure 1A An example of the interface between the frangible drive element and the head of a core bolt. Figure 2A Shown after the frangible drive element is separated from the core head Figure 1A Side view of the core bolt. Figure 2B Shown after separation of the frangible drive element Figure 1A view of a core bolt. Figure 2C Shown after being separated from the head Figure 1A Example of a removable drive element. Figure 3A Another example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 3B Yet another example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 4A Yet another example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 4B Shows Figure 4A view of a core bolt. Figure 6 An example of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 7AAn example of connecting holes through multiple substrates of a workpiece is shown, with a pointed bottom countersunk hole on the working side. Figure 7B Another example of a connecting hole through multiple base plates of a workpiece is shown, with a flat bottom counterbore on the working side. Figure 7C Yet another example of connecting holes through multiple substrates of a workpiece is shown. Figure 8 Another example of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown.

[0050] Refer again Figure 1A -C, 2A-C, 3A-B, 4A-B, 6, 7A-C, and 8, in one or more examples, a fastener system 600, 800 for connecting a plurality of substrates 602 having a workpiece 604 with a working side 606 and a blind side 608 is disclosed. The fastener system includes a nut member 610 and a core bolt 100, 400. The nut member 610 includes a nut hole 612 having an internal thread 614. The core bolt 100, 400 includes a head 106, a shank 108, and a frangible drive element 112, 412. The head 106 includes a recessed torque feature 202. The shank 108 extends axially from the head 106 to the distal end 104 of the core bolt 100, 400 along a central longitudinal axis 110. The shank 108 includes a threaded portion 102 between the distal end 104 and the head 106. The frangible drive element 112, 412 extends from the head 106 and projects outwardly along the central longitudinal axis 110 to define a proximal end 114 of the core bolt 100, 400. In another example of the fastener system 600, 800, the plurality of base plates 602 includes at least one composite base plate. In yet another example of the fastener system 600, 800, at the working side 606 of the workpiece 604, the connecting hole 702 through the plurality of base plates 602 includes a countersunk portion 704, a counterbored portion 706, a cylindrical portion 708, or any other suitable shaped portion (in any suitable combination).

[0051] In yet another example of the fastener system 600, 800, the nut member 610 is configured to arrange a nut hole 612 on the blind side 608 of the workpiece 604 over the connecting holes 702 through the plurality of base plates 602. In yet another example of the fastener system 600, 800, the nut member 610 is configured to be secured to the blind side 608 of the workpiece 604. In a further example, the nut member 610 is configured to be secured using any suitable combination of mechanical fasteners, nut plates, swaged retention mechanisms, adhesive bonding materials, gang channels, or any other suitable securing techniques. In another example of the fastener system 600, 800, the core bolt 100, 400 is configured to be inserted from the working side 606 of the workpiece 604 into the connecting holes 702 through the plurality of base plates 602. In another example of the fastener system 600 , 800 , the threaded portion 102 of the shank 108 of the core bolt 100 , 400 is configured to threadably engage the internal threads 614 of the nut member 610 .

[0052] In yet another example of the fastener system 600 , 800 , the head 106 of the core bolt 100 , 400 includes a flush head, a countersunk head, a protruding head, a raised head, or any other suitable type of head (in any suitable combination).

[0053] In yet another example of the fastener system 600, 800, the recessed torque feature 202 on the head 106 of the mandrel bolt 100, 400 includes a recessed offset cruciform drive feature, a recessed dovetail drive feature, a recessed crosshead drive feature, a recessed allen key drive feature, a recessed flat head drive feature, or any other recessed torque feature (in any suitable combination). In yet another example of the fastener system 600, 800, after the frangible drive element 112, 412 of the mandrel bolt 100, 400 is separated from the head 106, the recessed torque feature 202 on the head 106 facilitates rotating the mandrel bolt 100, 400 using at least one of an offset cruciform drive torque tool, a dovetail drive torque tool, a crosshead drive torque tool, an allen key torque tool, a flat head drive torque tool, or any other suitable tool in any suitable combination.

[0054] In yet another example of the fastener system 600, 800, the shank 108 of the core bolt 100, 400 opposes the recessed torsion feature 202 of the head 106. In yet another example of the fastener system 600, 800, the shank 108 of the core bolt 100, 400 includes a cylindrical body 302, a frusto-conical body 304, or any other suitably shaped body (in any suitable combination).

[0055] In yet another example of the fastener system 600, 800, the frangible drive element 112, 412 of the core bolt 100, 400 extends from the head 106 at the central base region 116 of the recessed torsion feature 202 and is configured to be engaged by a tool used to install the core bolt 100, 400. In a further example, the tool includes an end effector on a robotic arm, a handheld power tool, a hand tool, or any other suitable tool (in any suitable combination). In yet another further example, during installation of the core bolt 100, 400, the frangible drive element 112, 412 is separable from the head 106 at the central base region 116 of the recessed torsion feature 202 in response to a predetermined torque applied by the tool. In yet another example of the fastener system 600, 800, the frangible drive element 112, 412 of the core bolt 100, 400 includes an interface portion 118, 418, a torsion portion 120, 420, and a stem portion 124, 424. The interface portion 118, 418 extends from the head portion 106 and protrudes outward. The torsion portion 120, 420 includes a rotation feature 122, 422 at the proximal end 114 of the core bolt 100, 400. The stem portion 124, 424 extends axially along the central longitudinal axis 110 of the core bolt 100, 400 between the interface portion 118, 418 and the torsion portion 120, 420.

[0056] In a further example, the interface portion 118, 418 of the frangible drive element 112, 412 extends from the head 106 at the central base region 116 of the recessed torsion feature 202. In another further example, the rotational feature 122, 422 of the torsion portion 120, 420 includes a recessed spline drive feature, a recessed star drive feature, a recessed square lobe star drive feature, a recessed hexagonal star drive feature, a recessed hexagonal square lobe star drive feature, a relatively flat head feature, a recessed allen key drive feature, a hexagonal head feature, a recessed cross head drive feature, a recessed flat head drive feature, and any other suitable rotational feature (in any suitable combination).

[0057] In yet another further example, the rotation feature 122, 422 of the torsion portion 120, 420 facilitates rotating the core bolt 100, 400 using a spline drive torque tool, a star drive torque tool, a square lobe star drive torque tool, a hexagonal star drive torque tool, a hexagonal square lobe star drive torque tool, a opposed flat socket torque tool, an allen key torque tool, a hexagonal socket torque tool, a crosshead drive torque tool, a flathead drive torque tool, or any other suitable tool in any suitable combination. In yet another further example, the stem 124, 424 of the frangible drive element 112, 412 opposes the rotation feature 122, 422 of the torsion portion 120, 420. In yet another further example, the stem 124, 424 of the frangible drive element 112, 412 comprises an elongated cylindrical shape, an elongated hexagonal shape, an elongated multi-faceted shape, or any other suitable shape (in any suitable combination).

[0058] In another further example of the fastener systems 600, 800, the interface portion 118, 418 of the frangible drive element 112, 412 defines a break neck groove 126, which is disposed near the head 106 at the central base region 116 of the recessed torsion feature 202 to facilitate separation of the frangible drive element 112, 412 from the core bolt 100, 400 in response to a predetermined torque being applied at the torsion portion 120, 420 during installation of the core bolt 100, 400. In another further example of the fastener system 600, 800, the interface portion 118, 418 of the frangible drive element 112, 412 includes an interface body 204 that tapers from the shank 124, 424 to the head 106 at the central base region 116 of the recessed torsion feature 202 to facilitate separation of the frangible drive element 112, 412 from the core bolt 100, 400 in response to a predetermined torque being applied at the torsion portion 120, 420 during installation of the core bolt 100, 400. In yet a further example of the fastener systems 600, 800, the body 204 at the interface defines a break neck groove 126 disposed near the head 106 at the central base region 116 of the recessed torsion feature 202 to further facilitate separation of the frangible drive element 112, 412 from the core bolt 100, 400 in response to a predetermined torque being applied at the torsion portion 120, 420 during installation of the core bolt 100, 400.

[0059] In yet another example, the fastener system 600, 800 further includes a sleeve member 802 having an outer sleeve surface 804 with a lubricating coating. The sleeve member 802 is configured to be inserted through the plurality of connection holes 702 of the base plate 602 from the working side 606 of the workpiece 604. The core bolt 100, 400 is configured to be inserted into the central hole 806 of the sleeve member 802. In a further example, the lubricating coating on the outer sleeve surface 804 of the sleeve member 802 includes a conductive feature configured to provide electromagnetic energy shielding to the workpiece 604. In another further example, the outer sleeve surface 804 of the sleeve member 802 is coated with a conductive coating to provide electromagnetic energy shielding to the workpiece 604.

[0060] In yet another further example of the fastener system 600, 800, the sleeve member 802 further includes an inner sleeve surface 808, and the shank 108 of the core bolt 100, 400 includes an outer shank surface 810. At least one of the inner sleeve surface 808 and the outer shank surface 810 is coated with a lubricious coating. In yet another further example of the fastener system 600, 800, the sleeve member 802 further includes an elongated sleeve body 812 that defines the central bore 806. The elongated sleeve body 812 includes an outer sleeve surface 804, an inner sleeve surface 808 facing the central bore 806, a first end 814 associated with the working side 606 of the workpiece (604), and a second end 816 associated with the blind side 608 of the workpiece 604. At least the inner sleeve surface 808 tapers from a larger inner sleeve diameter proximate the first end 814 to a smaller inner sleeve diameter proximate the second end 816 such that the central bore 806 includes a frusto-conical sleeve bore 818. In yet a further example, the outer sleeve surface 804 of the sleeve member 802 is cylindrical such that the elongated sleeve body 812 includes a cylindrical sleeve body 820 having the frusto-conical sleeve bore 818.

[0061] In yet another further example, when the core bolt 100 , 400 is fully engaged with the nut member 610 , the shank 108 of the core bolt 100 , 400 is configured to cause the sleeve member 802 to radially expand, and the sleeve member 802 is configured to provide an interference fit within the connection hole 702 through the plurality of base plates 602 .

[0062] In another example, the fastener system 600, 800 further includes a thermoplastic polymer sealant 616 disposed within the cavity 822 between the nut member 610 and the blind side 608 of the workpiece 604. In a further example, the thermoplastic polymer sealant 616 provides electromagnetic energy protection to the workpiece 604.

[0063] In yet another example, the fastener system 600, 800 further includes a sealant cap member 618 having a dome and configured to be disposed on the nut member 610 on the blind side 608 of the workpiece 604. In a further example, the sealant cap member 618 provides electromagnetic energy shielding for the workpiece 604.

[0064] Overall reference Figure 1A -C, 2A-C, 3A-B, 4A-B, 6, 7A-C, and 8-15, as examples, the present disclosure relates to methods 900, 1400, 1500 for joining a plurality of substrates 602 having a workpiece 604 with a working side 606 and a blind side 608. Figure 1A An example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 1B Shows Figure 1A view of a core bolt. Figure 1C Shows Figure 1A An example of the interface between the frangible drive element and the head of a core bolt. Figure 2A Shows Figure 1A Side view of the core bolt after the removable drive element is separated from the core head. Figure 2B Shows Figure 1A Top view of the core bolt after separation of the easily removable drive element. Figure 2C Shows Figure 1A An example of the frangible drive element after being separated from the head. Figure 3A Another example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 3B Yet another example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 4A Yet another example of a core bolt of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 4B Shows Figure 4A view of a core bolt. Figure 6 An example of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown.

[0065] Figure 7A An example of connecting holes through multiple substrates of a workpiece is shown, with a pointed bottom countersunk hole on the working side. Figure 7B Another example of a connecting hole through multiple base plates of a workpiece is shown, with a flat bottom counterbore on the working side. Figure 7C Yet another example of connecting holes through multiple substrates of a workpiece is shown. Figure 8 Another example of a fastener system for connecting multiple base plates of a workpiece having a working side and a blind side is shown. Figure 9An example of a method 900 for joining a plurality of substrates 602 of a workpiece 604 having a working side 606 and a blind side 608 is provided. Figure 10 Provided Figure 9 An example of fixing 902 of the nut member 610. Figure 11 Provided Figure 9 An example of a rotation 906 of the core bolt 100 , 400 and a further rotation 908 of the core bolt 100 , 400 . Figure 12 Provided Figure 9 Other examples of rotation 906 of the core bolt 100 , 400 and further rotation 908 of the core bolt 100 , 400 . Figure 13 Provided Figure 9 Still other examples of rotation 906 of the core bolt 100 , 400 and further rotation 908 of the core bolt 100 , 400 . Figure 14 ,and Figure 9 In conjunction, an example of a method 1400 for joining a plurality of substrates 602 of a workpiece 604 having a working side 606 and a blind side 608 is provided. Figure 15 ,and Figure 9 In conjunction, an example of a method 1500 for joining a plurality of substrates 602 of a workpiece 604 having a working side 606 and a blind side 608 is provided.

[0066] Refer again Figure 1A -C, 2A-C, 3A-B, 4A-B, 6, 7A-C, and 9-13, in one or more examples, a method 900 for joining a plurality of substrates 602 having a workpiece 604 with a working side 606 and a blind side 608 (see Figure 9) includes securing 902 a nut member 610 on the blind side 608 of the workpiece 604, the nut member 610 including a nut hole 612 with internal threads 614, over the connecting hole 702 extending through the plurality of base plates 602. At 904, a core bolt 100, 400 is inserted into the connecting hole 702 from the working side 606 of the workpiece 604 until the distal end 104 of the core bolt 100, 400 contacts the nut member 610. The core bolt 100, 400 includes a head 106 having a concave torsion feature 202 and a shank 108 extending axially from the head 106 to the distal end 104 of the core bolt 100, 400 along a central longitudinal axis 110. The shank 108 includes a threaded portion 102 between the distal end 104 and the head 106. The core bolt 100, 400 also includes a frangible drive element 112, 412 extending from the head 106 and projecting outwardly along the central longitudinal axis 110 to define a proximal end 114 of the core bolt 100, 400. At 906, the core bolt 100, 400 is rotated to engage the threaded portion 102 with the internal threads 614 of the nut member 610. At 908, the core bolt 100, 400 is further rotated to further engage the nut member 610 until the frangible drive element 112, 412 is separated from the core bolt 100, 400 to complete the installation.

[0067] In another example of method 900, securing 902 the nut member 610 includes securing 1002 the nut member 610 using mechanical fasteners, nut plates, swaged retaining mechanisms, adhesive bonding materials, grouped channels, or any other suitable securing techniques in any suitable combination (see FIG. Figure 10 ) to the blind side 608 of the workpiece 604. In yet another example of the method 900, after the frangible drive element 112, 412 is separated from the head 106, the recessed torsion feature 202 on the head 106 facilitates rotation of the core bolt 100, 400 for removal and subsequent replacement from the working side 606 of the workpiece 604. In yet another example of the method 900, the shank 108 of the core bolt 100, 400 includes a cylindrical body 302, a frustoconical body 304, or any other suitably shaped body (in any suitable combination).

[0068] In yet another example of method 900, the frangible drive element 112, 412 of the core bolt 100, 400 extends from the head 106 at the central base region 116 of the recessed torsion feature 202 and is configured to be engaged by a tool to at least one of rotate 906 the core bolt 100, 400 and further rotate 908 the core bolt 100, 400. In a further example, the tool includes an end effector on a robotic arm, a handheld power tool, a hand tool, or any other suitable tool (in any suitable combination). In another further example, during the further rotation 908 of the core bolt 100, 400, in response to a predetermined torque being applied by the tool, the frangible drive element 112, 412 separates from the head 106 at the central base region 116 of the recessed torsion feature 202.

[0069] In another example of method 900, the frangible drive element 112, 412 of the core bolt 100, 400 includes an interface portion 118, 418, a torsion portion 120, 420, and a shank portion 124, 424. The interface portion 118, 418 extends from the head portion 106 and protrudes outward. The torsion portion 120, 420 includes a rotation feature 122, 422 at the proximal end 114 of the core bolt 100, 400. The shank portion 124, 424 extends axially along the central longitudinal axis 110 of the core bolt 100, 400 between the interface portion 118, 418 and the torsion portion 120, 420. The shank portion 124, 424 opposes the rotation feature 122, 422 of the torsion portion 120, 420. In a further example, the interface portion 118 , 418 of the frangible drive element 112 , 412 extends from the head 106 at the central base region 116 of the concave torsion feature 202 .

[0070] In another further example of method 900, the rotating 906 of the core bolt 100, 400 and the further rotating 908 of the core bolt 100, 400 include engaging 1102 the rotating features 122, 422 of the torsion portion 120, 420 on the frangible drive element 112, 412 using a tool (see Figure 11 At 1104, the core bolt 100, 400 is rotated using a tool to engage the threaded portion 102 of the shank 108 with the internal threads 614 of the nut member 610. At 1106, the core bolt 100, 400 is further rotated using a tool to further engage the nut member 610 until the interface portion 118, 418 breaks and the frangible drive element 112, 412 is separated from the core bolt 100, 400, thereby completing the installation.

[0071] In yet another further example, the interface portion 118, 418 of the frangible drive element 112, 412 includes a break neck groove 126 disposed proximate to the head 106 at the central base region 116 of the concave torsion feature 202. In this example of the method 900, the rotation 906 of the core bolt 100, 400 and the further rotation 908 of the core bolt 100, 400 include engaging 1202 the rotational features 122, 422 of the torsion portion 120, 420 on the frangible drive element 112, 412 using a tool (see FIG. Figure 12 At 1204, the core bolt 100, 400 is rotated using a tool to engage the threaded portion 102 of the shank 108 with the internal thread 614 of the nut member 610. At 1206, the core bolt 100, 400 is further rotated using a tool to further engage the nut member 610 until the interface portion 118, 418 breaks at the breakneck groove 126 and the frangible drive element 112, 412 is separated from the core bolt 100, 400, thereby completing the installation.

[0072] In yet another example, the interface portion 118, 418 of the frangible drive element 112, 412 includes an interface body 204 that tapers from the shank 124, 424 to the head 106 at the central base region 116 of the concave torsion feature 202. In this example of the method 900, the rotation 906 of the core bolt 100, 400 and the further rotation 908 of the core bolt 100, 400 include engaging 1302 the rotational features 122, 422 of the torsion portion 120, 420 on the frangible drive element 112, 412 using a tool (see FIG. Figure 13 At 1304, the core bolt 100, 400 is rotated with a tool to engage the threaded portion 102 of the shank 108 with the internal threads 614 of the nut member 610. At 1306, the core bolt 100, 400 is further rotated with the tool to further engage the nut member 610 until the body 204 at the interface breaks at the central base region 116 of the recessed torsion feature 202 on the head 106 of the core bolt 100, 400 and the frangible drive element 112, 412 is separated from the core bolt 100, 400, completing the installation.

[0073] Refer again Figure 1A -C, 4A-B, 6, 7A-C, 8, 9 and 14, in one or more examples, a method 1400 for joining a plurality of substrates 602 of a workpiece 604 having a working side 606 and a blind side 608 (see Figure 14 )include Figure 9Method 1400 continues from 902 to 1402, where a sleeve member 802 is inserted from a working side 606 of a workpiece 604 through the connection holes 702 of the plurality of substrates 602. The sleeve member 802 includes an outer sleeve surface 804 having a lubricating coating. In method 1400, inserting 904 the core bolt 100, 400 includes inserting 1404 the core bolt 100, 400 into the central hole 806 of the sleeve member 802.

[0074] In another example of the method 1400, rotating 906 the core bolt 100, 400 includes radially expanding 1406 the sleeve member 802 within the connection hole 702 through the plurality of base plates 602 when the core bolt 100, 400 is fully engaged with the nut member 610. In this example, further rotating 908 the core bolt 100, 400 includes providing 1408 an interference fit for the sleeve member 802 within the connection hole 702 in response to the radial expansion of the sleeve member 802 when the core bolt 100, 400 is fully engaged with the nut member 610.

[0075] Refer again Figure 1A -C, 6, 8, 9 and 15, in one or more examples, a method 1500 for joining a plurality of substrates 602 of a workpiece 604 having a working side 606 and a blind side 608 (see Figure 15 ) includes applying 1502 a thermoplastic polymer sealant 616 to the nut member 610 such that, in conjunction with securing 902 the nut member 610, the thermoplastic polymer sealant 616 at least partially fills the cavity 822 between the nut member 610 and the blind side 608 of the workpiece 604. The method 1500 continues from 1502 to 902. In another example, the method 1500 continues from 902 to 1504 where the sealant cap member 618 is mounted on the nut member 610 on the blind side 608 of the workpiece 604.

[0076] Examples of core bolts, fastener systems, and methods for connecting multiple base plates with workpieces having working and blind sides may be associated with or used in an aircraft manufacturing environment. While an aircraft example is described, the examples and principles disclosed herein may be applicable to other products in the aerospace industry and other industries, such as the automotive, aerospace, construction, and other design and manufacturing industries. Therefore, in addition to aircraft, the examples and principles disclosed herein may also be applicable to various products used in the manufacture of various types of vehicles and the construction of various types of buildings.

[0077] The foregoing detailed description refers to the accompanying drawings, which illustrate specific examples described in the present disclosure. Other examples with different structures and operations do not depart from the scope of the present disclosure. The same reference number may refer to the same feature, element or component in different drawings. Throughout the present disclosure, any one of the multiple projects may be referred to as a project individually, and multiple projects may be collectively referred to as projects and may be referred to with the same reference number. In addition, as used herein, a feature, element, component or step preceded by "a" or "a" should be understood as not excluding multiple features, elements, components or steps, unless such exclusion is explicitly stated.

[0078] Provided above are exemplary, non-exhaustive examples (which may, but are not necessarily claimed) of the subject matter of the present disclosure. Reference herein to an "example" means that one or more features, structures, elements, components, characteristics and / or operational steps described in conjunction with the example are included in at least one aspect, embodiment and / or implementation of the subject matter of the present disclosure. Therefore, throughout this disclosure, the phrases "an example," "another example," "one or more examples," and similar expressions may, but are not necessarily, refer to the same example. In addition, the subject matter representing any one example may, but is not necessarily, include the subject matter representing any other example. In addition, the subject matter representing any one example may, but is not necessarily, be combined with the subject matter representing any other example.

[0079] As used herein, a system, device, apparatus, structure, article, element, component, or hardware that is “configured to” perform a specified function is actually capable of performing the specified function without any modification, rather than merely having the potential to perform the specified function after further modification. In other words, a system, device, apparatus, structure, article, element, component, or hardware that is “configured to” perform a specified function is specifically selected, created, implemented, utilized, programmed, and / or designed for the purpose of performing the specified function. As used herein, “configured to” means that the existing features of a system, apparatus, structure, article, element, component, or hardware are capable of enabling the system, apparatus, structure, article, element, component, or hardware to perform the specified function without further modification. For the purposes of this disclosure, a system, device, apparatus, structure, article, element, component, or hardware that is described as “configured to” perform a specific function may additionally or alternatively be described as “configured to” and / or “operable to” perform that function.

[0080] Unless otherwise indicated, the terms "first," "second," "third," etc., are used herein merely as labels and are not intended to impose order, position, or hierarchical requirements on the items to which these terms refer. Furthermore, reference to an item, for example, "second," does not require or preclude the presence of an item, for example, "first" or lower-numbered, and / or an item, for example, "third" or higher-numbered.

[0081] As used herein, when used in conjunction with a list of items, the phrase "at least one of" means that different combinations of one or more of the listed items may be used, and only one of each item in the list may be required. For example, "at least one of item A, item B, and item C" may include, but is not limited to, item A or item A and item B. This example may also include item A, item B, and item C or item B and item C. In other examples, "at least one of" may be, for example, but not limited to, two items A, one item B, and ten items C; four items B and seven items C; and other suitable combinations. As used herein, the term "and / or" and the " / " symbol include any and all combinations of one or more of the associated listed items.

[0082] As used herein, the terms "coupled," "coupling," and similar terms refer to two or more elements being connected, linked, fastened, attached, coupled, communicated, or otherwise associated (e.g., mechanically, electrically, fluidically, optically, electromagnetically) with one another. In various examples, elements can be associated directly or indirectly. For example, element A can be directly associated with element B. As another example, element A can be indirectly associated with element B, e.g., through another element C. It will be understood that not all of the associations between the various disclosed elements are necessarily shown. Thus, connections other than those shown in the figures may also exist.

[0083] As used herein, the term "approximately" refers to or indicates a state that is close to a stated state but not exactly the stated state, yet is still capable of performing a desired function or achieving a desired result. For example, the term "approximately" refers to a state that is within an acceptable predetermined tolerance or accuracy, such as a state within 10% of the stated state. However, the term "approximately" does not exclude a state that is exactly the stated state. As used herein, the term "substantially" refers to a state that is essentially the stated state that performs a desired function or achieves a desired result.

[0084] In the accompanying drawings, the above Figure 1A -C, 2A-C, 3A-B, 4A-B, 6, 7A-C and 8 may illustrate functional elements, features or components thereof, but do not necessarily imply any specific structure. Therefore, modifications, additions and / or omissions may be made to the illustrated structures. In addition, those skilled in the art will appreciate that the above Figure 1A Not all elements, features, and / or components described and illustrated in 2A-C, 2A-C, 3A-B, 4A-B, 6, 7A-C, and 8 need to be included in every example, and not all elements, features, and / or components described herein are necessarily depicted in every exemplary example. Figure 1A-C, 2A-C, 3A-B, 4A-B, 6, 7A-C and 8 described and illustrated in some elements, features and / or components can be combined in various ways without having to include Figure 1A -C, 2A-C, 3A-B, 4A-B, 6, 7A-C and 8, other features described and illustrated in other figures and / or accompanying disclosure, even if one or more such combinations are not explicitly illustrated herein. Likewise, other features not limited to the examples shown may be combined with some or all of the features shown and described herein. Unless expressly stated otherwise, the above Figure 1A The illustrative examples of the examples shown in 2A-C, 2A-C, 3A-B, 4A-B, 6, 7A-C, and 8 are not meant to imply structural limitations with respect to the exemplary examples. Rather, while an exemplary structure is shown, it should be understood that the structure may be modified as appropriate. Thus, modifications, additions, and / or omissions may be made to the illustrated structures. Furthermore, in Figure 1A In each of Figures 2A-C, 2A-C, 3A-B, 4A-B, 6, 7A-C and 8, elements, features and / or components serving similar or at least substantially similar purposes are labeled with the same reference numerals, and such elements, features and / or components may not be referenced herein. Figure 1A -C, 2A-C, 3A-B, 4A-B, 6, 7A-C and 8 are discussed in detail. Similarly, Figure 1A -C, 2A-C, 3A-B, 4A-B, 6, 7A-C, and 8, all elements, features, and / or components may not be labeled, but their associated reference numerals may be utilized herein for consistency.

[0085] In the above Figure 9-15 In the disclosure, boxes may represent operations, steps, and / or parts thereof, and the lines connecting the various boxes do not imply any specific order or dependency of the operations or parts thereof. It will be understood that not all dependencies between the various disclosed operations must be shown. Figure 9-15 The accompanying disclosure describing the operations of the disclosed method proposed herein should not be construed as necessarily determining the order in which the operations are performed. Rather, although an exemplary order is indicated, it will be understood that the order of the operations can be modified when appropriate. Therefore, the operations shown can be modified, added to, and / or omitted, and certain operations can be performed in a different order or simultaneously. Furthermore, those skilled in the art will understand that not all of the described operations need to be performed.

[0086] Furthermore, references throughout this specification to features, benefits, or similar expressions used herein do not imply that all of the features and advantages that may be achieved through the examples disclosed herein should be or are present in any single example. Rather, references to features and benefits are understood to mean that a specific feature, benefit, or characteristic described in connection with one example is included in at least one example. Thus, discussions of features, benefits, and similar expressions used throughout this disclosure may, but do not necessarily, refer to the same example.

[0087] Examples of the subject matter disclosed herein can be found in Figure 16 Aircraft manufacturing and service method 1600 is shown and Figure 17 16. The method and system disclosed herein for associating test data of a test component with an end-product coordinate system may be used in aircraft manufacturing. During pre-production, the service method 1600 may include the development and design of the aircraft 1700 (block 1602) and material procurement (block 1604). During production, component and subassembly manufacturing (block 1606) and system integration (block 1608) of the aircraft 1700 may be performed. Thereafter, the aircraft 1700 may be certified and delivered (block 1610) to be placed into service (block 1612). During service, the aircraft 1700 may be scheduled for routine maintenance and service (block 1614). Routine maintenance and service may include modification, reconfiguration, refurbishment, etc. of one or more systems of the aircraft 1700.

[0088] Each of the processes of service method 1600 may be performed or carried out by a system integrator, a third party, and / or an operator (e.g., a customer). For purposes of this description, a system integrator may include, but is not limited to, any number of aircraft manufacturers and major system subcontractors; a third party may include, but is not limited to, any number of vendors, subcontractors, and suppliers; and an operator may include, for example, an airline, a leasing company, a military entity, a service organization, or the like.

[0089] like Figure 17 As shown, an aircraft 1700 produced by service method 1600 may include an airframe 1702, a plurality of high-level systems 1704, and an interior 1706. Examples of high-level systems 1704 include one or more of a propulsion system 1708, an electrical system 2160, a hydraulic system 1712, and an environmental system 1714. Any number of other systems may be included. While an aerospace example is shown, the principles disclosed herein may be applicable to other industries, such as the automotive industry. Thus, in addition to aircraft 1700, the principles disclosed herein may also be applicable to other vehicles, such as land vehicles, sea vehicles, space vehicles, and the like.

[0090] The disclosed systems and methods for associating test data for a test component with an end-item coordinate system can be used at any one or more stages of the manufacturing and service method 1600. For example, during component and subassembly manufacturing (block 1606), the corresponding components or subassemblies can be manufactured or produced in a manner similar to the components or subassemblies produced when the aircraft 1700 is in service (block 1612). Furthermore, one or more instances of the described system(s), method(s), or combination thereof can be utilized during the production phase (blocks 1606 and 1608), for example, by significantly speeding up or reducing the cost of assembling the aircraft 1700. Similarly, one or more instances of the described system or method implementations or combination thereof can be used, for example, but not limited to, while the aircraft 1700 is in service (block 1612) and / or during maintenance and service (block 1614).

[0091] The features, benefits, and characteristics of one example may be combined in any appropriate manner in one or more other examples. One skilled in the relevant art will recognize that the examples described herein may be practiced without one or more specific features or benefits of a particular example. In other cases, other features and benefits may be recognized in certain examples that may not be present in all examples. Furthermore, while various examples of core bolts 100, 400, fastener systems 600, 800, and methods 900, 1400, 1500 for connecting multiple substrates 602 of a workpiece 604 having a working side 606 and a blind side 608 have been shown and described, modifications may occur to one skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims.

[0092] Illustrative Examples

[0093] 1. A core bolt (100, 400) of a fastener system (600, 800) for connecting a plurality of base plates (602) of a workpiece (604) having a working side (606) and a blind side (608), the core bolt comprising:

[0094] a head portion (106), the head portion (106) including a concave twist feature (202);

[0095] a shank (108) extending axially from the head (106) along a central longitudinal axis (110) to a distal end (104) of the core bolt (100, 400), the shank (108) including a threaded portion (102) between the distal end (104) and the head (106); and

[0096] A frangible drive element (112, 412) extends from the recessed torsion feature (202) of the head (106) and projects outwardly along the central longitudinal axis (110) to define a proximal end (114) of the core bolt (100, 400).

[0097] 2. The core bolt according to example 1, wherein the core bolt (100, 400) comprises a metal material.

[0098] 3. The core bolt according to example 2, wherein the metal material comprises at least one of stainless steel, titanium, a titanium alloy, a cobalt-chromium alloy, and a nickel-titanium alloy.

[0099] 4. The core bolt according to example 1, wherein the head (106) comprises at least one of a flush head, a pointed head, a protruding head, and a convex head.

[0100] 5. The core bolt of Example 1, wherein the recessed torsion feature (202) of the head (106) comprises at least one of a recessed offset cross drive feature, a recessed dovetail drive feature, a recessed crosshead drive feature, a recessed hex key drive feature, and a recessed flat head drive feature.

[0101] 6. A core bolt according to Example 1, wherein, after the removable drive element (112, 412) is separated from the head (106), the recessed torque feature (202) of the head (106) facilitates rotating the core bolt (100, 400) using at least one of an offset cross-drive torque tool, a dovetail drive torque tool, a cross-head drive torque tool, an allen key torque tool, and a flat-head drive torque tool.

[0102] 7. The core bolt of example 1, wherein the shank (108) is opposite the concave torsion feature (202) of the head (106).

[0103] 8. The core bolt of example 1, wherein the shank (108) comprises at least one of a cylindrical body (302) and a frustoconical body (304).

[0104] 9. The core bolt of Example 1, wherein the frangible drive element (112, 412) extends from the head (106) at a central base region (116) of the recessed torsion feature (202) and is configured to be engaged by a tool used to install the core bolt (100, 400).

[0105] 10. The core bolt of example 9, wherein the tool comprises at least one of an end effector on a robotic arm, a handheld power tool, and a hand tool.

[0106] 11. A core bolt according to Example 9, wherein during installation of the core bolt (100, 400), in response to a predetermined torque being applied by the tool, the removable drive element (112, 412) is separable from the head (106) at the central base area (116) of the recessed torsional feature (202).

[0107] 12. The core bolt according to example 11, wherein the predetermined torque is based at least in part on at least one of the following: a diameter of the core bolt (100, 400), a surface coating on an internal thread (614) of a nut member (610) into which the core bolt (100, 400) is installed, a friction level of the internal thread (614) of the nut member (610), a contact between the shank (108) of the core bolt (100, 400) and the nut member (610) into which the core bolt (100, 400) is installed, The friction level between the connecting holes (702) of the multiple base plates (602), the friction level between the shank (108) of the core bolt (100, 400) and the sleeve member (802) into which the core bolt (100, 400) is inserted, the effect of lubricant on the friction experienced by the core bolt (100, 400) during installation, and the preload tension at the proximal end (114) of the detachable drive element (112, 412) within the core bolt (100, 400).

[0108] 13. The core bolt according to example 1, wherein the detachable drive element (112, 412) comprises:

[0109] an interface portion (118, 418), the interface portion (118, 418) extending from the head portion (106) and protruding outward;

[0110] a torsion portion (120, 420) comprising a rotational feature (122, 422) at the proximal end (114) of the core bolt (100, 400); and

[0111] A shank portion (124, 424) extends axially along the central longitudinal axis (110) of the core bolt (100, 400) between the interface portion (118, 418) and the torsion portion (120, 420).

[0112] 14. The core bolt of example 13, wherein the interface portion (118, 418) of the frangible drive element (112, 412) extends from the head (106) at a central base region (116) of the recessed torsion feature (202).

[0113] 15. The core bolt of Example 13, wherein the rotational feature (122, 422) of the torsion portion (120, 420) comprises at least one of a recessed spline drive feature, a recessed star drive feature, a recessed square lobe star drive feature, a recessed hexagonal star drive feature, a recessed hexagonal square lobe star drive feature, a relatively flat head feature, a recessed hexagonal key drive feature, a hexagonal head feature, a recessed cross head drive feature, and a recessed flat head drive feature.

[0114] 16. The core bolt of Example 13, wherein the rotational feature (122, 422) of the torque portion (120, 420) facilitates rotating the core bolt (100, 400) using at least one of a spline drive torque tool, a star drive torque tool, a square lobe star drive torque tool, a hexagonal star drive torque tool, a hexagonal square lobe star drive torque tool, a relative flat socket torque tool, a hex key torque tool, a hex socket torque tool, a cross head drive torque tool, and a flat head drive torque tool.

[0115] 17. The core bolt of example 13, wherein the shank portion (124, 424) is opposite to the rotational feature (122, 422) of the torsion portion (120, 420).

[0116] 18. The core bolt of example 13, wherein the shank (124, 424) comprises at least one of an elongated cylindrical shape, an elongated hexagonal shape, and an elongated polyhedral shape.

[0117] 19. According to the core bolt described in Example 13, the interface portion (118, 418) defines a neck break groove (126), and the neck break groove (126) is arranged near the head (106) at the central base area (116) of the recessed torsion feature (202) to facilitate the separation of the detachable drive element (112, 412) from the core bolt (100, 400) in response to a predetermined torque being applied to the torsion portion (120, 420) during the installation process of the core bolt (100, 400).

[0118] 20. The core bolt according to example 13, wherein the interface portion (118, 418) comprises:

[0119] An interface body (204) is tapered from the shank (124, 424) to the head (106) at a central base region (116) of the recessed torsion feature (202) to facilitate separation of the frangible drive element (112, 412) from the core bolt (100, 400) in response to a predetermined torque being applied to the torsion portion (120, 420) during installation of the core bolt (100, 400).

[0120] 21. According to the core bolt described in Example 20, the main body (204) at the interface defines a neck break groove (126), and the neck break groove (126) is arranged near the head (106) at the central base area (116) of the recessed torsion feature (202) to further facilitate the separation of the detachable drive element (112, 412) from the core bolt (100, 400) in response to a predetermined torque being applied to the torsion portion (120, 420) during the installation process of the core bolt (100, 400).

[0121] 22. A fastener system (600, 800) for connecting a plurality of base plates (602) of a workpiece (604) having a working side (606) and a blind side (608), the fastener system comprising:

[0122] a nut member (610) comprising a nut hole (612) having an internal thread (614); and

[0123] A core bolt (100, 400), the core bolt (100, 400) comprising:

[0124] a head portion (106), the head portion (106) including a concave twist feature (202);

[0125] a shank (108) extending axially along a central longitudinal axis (110) from the head (106) to a distal end (104) of the core bolt (100, 400), the shank (108) including a threaded portion (102) between the distal end (104) and the head (106); and

[0126] A frangible drive element (112, 412) extends from the head (106) and projects outwardly along the central longitudinal axis (110) to define a proximal end (114) of the core bolt (100, 400).

[0127] 23. The fastener system of example 22, wherein the plurality of substrates (602) includes at least one composite substrate.

[0128] 24. A fastener system according to Example 22, wherein, on the working side (606) of the workpiece (604), the connecting hole (702) passing through the plurality of substrates (602) includes at least one of a pointed bottom countersunk portion (704), a flat bottom countersunk portion (706) and a cylindrical portion (708).

[0129] 25. The fastener system of Example 22, wherein the nut member (610) is configured to arrange the nut hole (612) on the blind side (608) of the workpiece (604) over a connection hole (702) passing through a plurality of substrates (602).

[0130] 26. The fastener system of example 22, wherein the nut member (610) is configured to be secured to the blind side (608) of the workpiece (604).

[0131] 27. The fastener system of example 26, wherein the nut member (610) is configured to be secured using at least one of a mechanical fastener, a nut plate, a swage retention mechanism, an adhesive bonding material, and a grouped channel.

[0132] 28. The fastener system of example 22, wherein the core bolt (100, 400) is configured to be inserted through the connection holes (702) of the plurality of base plates (602) from the working side (606) of the workpiece (604).

[0133] 29. The fastener system of example 22, wherein the threaded portion (102) of the shank (108) of the core bolt (100, 400) is configured to threadably engage the internal threads (614) of the nut member (610).

[0134] 30. The fastener system of example 22, wherein the head (106) of the core bolt (100, 400) comprises at least one of a flush head, a countersunk head, a protruding head, and a raised head.

[0135] 31. A fastener system according to Example 22, wherein the recessed torsion feature (202) on the head (106) of the core bolt (100, 400) includes at least one of a recessed offset cross drive feature, a recessed dovetail drive feature, a recessed cross head drive feature, a recessed hex key drive feature, and a recessed flat head drive feature.

[0136] 32. A fastener system according to Example 22, wherein, after the removable drive element (112, 412) of the core bolt (100, 400) is separated from the head (106), the recessed torque feature (202) of the head (106) facilitates rotating the core bolt (100, 400) using at least one of an offset cross-drive torque tool, a dovetail drive torque tool, a cross-head drive torque tool, an allen key torque tool, and a flat-head drive torque tool.

[0137] 33. The fastener system of example 22, wherein the shank (108) of the core bolt (100, 400) is opposite the concave torsion feature (202) of the head (106).

[0138] 34. The fastener system of example 22, wherein the shank (108) of the core bolt (100, 400) comprises at least one of a cylindrical body (302) and a frustoconical body (304).

[0139] 35. A fastener system according to Example 22, wherein the removable drive element (112, 412) of the core bolt (100, 400) extends from the head (106) at a central base area (116) of the recessed torsion feature (202) and is configured to be engaged by a tool used to install the core bolt (100, 400).

[0140] 36. The fastener system of example 35, wherein the tool comprises at least one of an end effector on a robotic arm, a handheld power tool, and a hand tool.

[0141] 37. A fastener system according to Example 35, wherein during installation of the core bolt (100, 400), the removable drive element (112, 412) is separable from the head (106) at a central base area (116) of the recessed torsional feature (202) in response to a predetermined torque being applied by the tool.

[0142] 38. The fastener system of example 22, wherein the frangible drive element (112, 412) of the core bolt (100, 400) comprises:

[0143] an interface portion (118, 418), the interface portion (118, 418) extending from the head portion (106) and protruding outward;

[0144] a torsion portion (120, 420) comprising a rotational feature (122, 422) at a proximal end (114) of the core bolt (100, 400); and

[0145] A rod portion (124, 424) extends axially along the central longitudinal axis (110) of the core bolt (100, 400) between the interface portion (118, 418) and the torsion portion (120, 420).

[0146] 39. The fastener system of example 38, wherein the interface portion (118, 418) of the frangible drive element (112, 412) extends from the head (106) at a central base region (116) of the recessed torsion feature (202).

[0147] 40. A fastener system according to Example 38, wherein the rotational feature (122, 422) of the torsion portion (120, 420) includes at least one of a recessed spline drive feature, a recessed star drive feature, a recessed square lobe star drive feature, a recessed hexagonal star drive feature, a recessed hexagonal square lobe star drive feature, a relatively flat head feature, a recessed hexagonal key drive feature, a hexagonal head feature, a recessed cross head drive feature, and a recessed flat head drive feature.

[0148] 41. A fastener system according to Example 38, wherein the rotational feature (122, 422) of the torque portion (120, 420) facilitates rotating the core bolt (100, 400) using at least one of a spline drive torque tool, a star drive torque tool, a square lobe star drive torque tool, a hexagonal star drive torque tool, a hexagonal square lobe star drive torque tool, a relative flat socket torque tool, a hex key torque tool, a hex socket torque tool, a cross head drive torque tool, and a flat head drive torque tool.

[0149] 42. The fastener system of example 38 wherein the stem portion (124, 424) of the frangible drive element (112, 412) opposes the rotational feature (122, 422) of the torsion portion (120, 420).

[0150] 43. The fastener system of example 38, wherein the stem (124, 424) of the frangible drive element (112, 412) comprises at least one of an elongated cylindrical shape, an elongated hexagonal shape, and an elongated polyhedral shape.

[0151] 44. According to the fastener system of Example 38, the interface portion (118, 418) of the detachable drive element (112, 412) defines a neck break groove (126), and the neck break groove (126) is arranged near the head (106) at the central base area (116) of the recessed torsion feature (202) to facilitate the separation of the detachable drive element (112, 412) from the core bolt (100, 400) in response to a predetermined torque being applied at the torsion portion (120, 420) during the installation process of the core bolt (100, 400).

[0152] 45. The fastener system of example 38, wherein the interface portion (118, 418) of the frangible drive element (112, 412) comprises:

[0153] An interface body (204) is tapered from the shank (124, 424) to the head (106) at a central base region (116) of the recessed torsion feature (202) to facilitate separation of the frangible drive element (112, 412) from the core bolt (100, 400) in response to a predetermined torque being applied to the torsion portion (120, 420) during installation of the core bolt (100, 400).

[0154] 46. ​​According to the fastener system of Example 45, the body (204) at the interface defines a break neck groove (126), and the break neck groove (126) is arranged near the head (106) at the central base area (116) of the recessed torsion feature (202) to further facilitate the separation of the detachable drive element (112, 412) from the core bolt (100, 400) in response to a predetermined torque being applied to the torsion portion (120, 420) during the installation process of the core bolt (100, 400).

[0155] 47. The fastener system of example 22, further comprising:

[0156] A sleeve member (802) includes an outer sleeve surface (804) having a lubricating coating, the sleeve member (802) being configured to be inserted through the connecting holes (702) of the plurality of substrates (602) from a working side (606) of the workpiece (604), wherein the core bolt (100, 400) is configured to be inserted into a center hole (806) of the sleeve member (802).

[0157] 48. A fastener system according to Example 47, wherein the lubricating coating on the outer sleeve surface (804) of the sleeve member (802) includes a conductive feature, and the conductive feature is configured to provide electromagnetic energy protection to the workpiece (604).

[0158] 49. The fastener system of example 47, wherein the outer sleeve surface (804) of the sleeve member (802) is coated with a conductive coating to provide electromagnetic energy protection to the workpiece (604).

[0159] 50. According to the fastener system of Example 47, the sleeve member (802) also includes an inner sleeve surface (808), and the shank (108) of the core bolt (100, 400) includes an outer shank surface (810), wherein at least one of the inner sleeve surface (808) and the outer shank surface (810) is coated with the lubricating coating.

[0160] 51. The fastener system of example 47, wherein the sleeve member (802) further comprises:

[0161] an elongated sleeve body (812) defining the central bore (806), the elongated sleeve body (812) including an outer sleeve surface (804), an inner sleeve surface (808) facing the central bore (806), a first end (814) associated with the working side (606) of the workpiece (604), and a second end (816) associated with the blind side (608) of the workpiece (604), and

[0162] Wherein at least the inner sleeve surface (808) tapers from a larger inner sleeve diameter proximate the first end (814) to a smaller inner sleeve diameter proximate the second end (816) such that the central bore (806) comprises a frustoconical sleeve bore (818).

[0163] 52. A fastener system according to Example 51, wherein the outer sleeve surface (804) of the sleeve member (802) is cylindrical, so that the elongated sleeve body (812) includes a cylindrical sleeve body (820) having the frustoconical sleeve hole (818).

[0164] 53. A fastener system according to Example 47, wherein, when the core bolt (100, 400) is fully engaged with the nut member (610), the shank (108) of the core bolt (100, 400) is configured to cause the sleeve member (802) to expand radially, and the sleeve member (802) is configured to provide an interference fit within the connecting hole (702) passing through the multiple substrates (602).

[0165] 54. The fastener system of example 22, further comprising:

[0166] A thermoplastic polymer sealant (616) is disposed within a cavity (822) between the nut member (610) and the blind side (608) of the workpiece (604).

[0167] 55. The fastener system of example 54, wherein the thermoplastic polymer sealant (616) provides electromagnetic energy protection to the workpiece (604).

[0168] 56. The fastener system of example 22, further comprising:

[0169] A sealant cap member (618) includes a dome and is configured to be disposed on the nut member (610) on the blind side (608) of the workpiece (604).

[0170] 57. The fastener system of example 56, wherein the sealant cap member (618) provides electromagnetic energy protection to the workpiece (604).

[0171] 58. A method (900) for joining a plurality of substrates (602) of a workpiece (604) having a working side (606) and a blind side (608), the method comprising:

[0172] Fixing (902) a nut member (610) on the blind side (608) of the workpiece (604) on the connecting hole (702) passing through the plurality of base plates (602), the nut member (610) including a nut hole (612) having an internal thread (614);

[0173] A core bolt (100, 400) is inserted (904) into the connecting hole (702) from the working side (606) of the workpiece (604) until the distal end (104) of the core bolt (100, 400) contacts the nut member (610), the core bolt (100, 400) including a head (106) and a shank (108), the head (106) having a concave torsion feature (202), the shank (108) being axially oriented from the head (106) along a central longitudinal axis (110). The core bolt (100, 400) extends to a distal end (104) of the core bolt (100, 400), the shank (108) including a threaded portion (102) between the distal end (104) and the head (106), the core bolt (100, 400) further including a frangible drive element (112, 412), the frangible drive element (112, 412) extending from the head (106) and projecting outwardly along the central longitudinal axis (110) to define a proximal end (114) of the core bolt (100, 400);

[0174] rotating (906) the core bolt (100, 400) to engage the threaded portion (102) with the internal thread (614) of the nut member (610); and

[0175] The core bolt (100, 400) is further rotated (908) to further engage the nut member (610) until the frangible drive element (112, 412) is separated from the core bolt (100, 400) to complete the installation.

[0176] 59. The method of example 58, wherein the securing (902) of the nut member (610) comprises:

[0177] The nut member (610) is secured (1002) to the blind side (608) of the workpiece (604) using at least one of a mechanical fastener, a nut plate, a swage retention mechanism, an adhesive bonding material, and a set of channels.

[0178] 60. A method according to Example 58, wherein, after the removable drive element (112, 412) is separated from the head (106), the recessed torsion feature (202) on the head (106) facilitates rotation of the core bolt (100, 400) for removal and subsequent replacement from the working side (606) of the workpiece (604).

[0179] 61. The method of example 58, wherein the shank (108) of the core bolt (100, 400) comprises at least one of a cylindrical body (302) and a frustoconical body (304).

[0180] 62. A method according to Example 58, wherein the removable drive element (112, 412) of the core bolt (100, 400) extends from the head (106) at a central base area (116) of the recessed torsional feature (202) and is configured to be engaged by a tool to perform at least one of rotation (906) of the core bolt (100, 400) and further rotation (908) of the core bolt (100, 400).

[0181] 63. The method of example 62, wherein the tool comprises at least one of an end effector on a robotic arm, a handheld power tool, and a hand tool.

[0182] 64. A method according to Example 62, wherein during further rotation (908) of the core bolt (100, 400), in response to a predetermined torque being applied by the tool, the removable drive element (112, 412) separates from the head (106) at the central base area (116) of the recessed torsional feature (202).

[0183] 65. The method of example 58, wherein the frangible drive element (112, 412) of the core bolt (100, 400) comprises:

[0184] an interface portion (118, 418), the interface portion (118, 418) extending from the head portion (106) and protruding outward;

[0185] a torsion portion (120, 420) comprising a rotational feature (122, 422) at a proximal end (114) of the core bolt (100, 400); and

[0186] A rod portion (124, 424) extends axially along the central longitudinal axis (110) of the core bolt (100, 400) between the interface portion (118, 418) and the torsion portion (120, 420), the rod portion (124, 424) being opposite to the rotational feature (122, 422) of the torsion portion (120, 420).

[0187] 66. The method of example 65, wherein the interface portion (118, 418) of the frangible drive element (112, 412) extends from the head (106) at a central base region (116) of the recessed torsional feature (202).

[0188] 67. The method of example 65, wherein the rotating (906) of the core bolt (100, 400) and the further rotating (908) of the core bolt (100, 400) comprise:

[0189] engaging (1102) the rotational feature (122, 422) of the torsion portion (120, 420) on the frangible drive element (112, 412) with a tool;

[0190] rotating the core bolt (100, 400) using (1104) the tool to engage the threaded portion (102) of the shank (108) with the internal thread (614) of the nut member (610); and

[0191] The core bolt (100, 400) is further rotated using the tool (1106) to further engage the nut member (610) until the interface portion (118, 418) breaks and the frangible drive element (112, 412) is separated from the core bolt (100, 400) to achieve installation.

[0192] 68. The method of example 65, wherein the interface portion (118, 418) of the frangible drive element (112, 412) defines a break neck groove (126), the break neck groove (126) being disposed proximate the head (106) at a central base region (116) of the concave torsion feature (202), the rotating (906) of the core bolt (100, 400) and the further rotating (908) of the core bolt (100, 400) comprising:

[0193] engaging (1202) the rotational feature (122, 422) of the torsion portion (120, 420) on the frangible drive element (112, 412) with a tool;

[0194] rotating the core bolt (100, 400) using (1204) the tool to engage the threaded portion (102) of the shank (108) with the internal thread (614) of the nut member (610); and

[0195] The core bolt (100, 400) is further rotated using the tool (1206) to further engage with the nut member (610) until the interface portion (118, 418) breaks at the break neck groove (126) and the detachable drive element (112, 412) is separated from the core bolt (100, 400) to achieve the installation.

[0196] 69. The method of example 65, wherein the interface portion (118, 418) of the frangible drive element (112, 412) includes an interface body (204) that tapers from the shank (124, 424) to the head (106) at a central base region (116) of the recessed torsion feature (202), the rotating (906) of the core bolt (100, 400) and the further rotating (908) of the core bolt (100, 400) comprising:

[0197] engaging (1302) the rotational feature (122, 422) of the torsion portion (120, 420) on the frangible drive element (112, 412) with a tool;

[0198] rotating the core bolt (100, 400) using (1304) the tool to engage the threaded portion (102) of the shank (108) with the internal threads (614) of the nut member (610); and

[0199] The core bolt (100, 400) is further rotated using the tool (1306) to further engage with the nut member (610) until the interface body (204) breaks at the central base area (116) of the recessed torsional feature (202) on the head (106) of the core bolt (100, 400) and the removable drive element (112, 412) is separated from the core bolt (100, 400) to achieve the installation.

[0200] 70. The method (1400) of example 58, further comprising:

[0201] inserting (1402) a sleeve member (802) from the working side (606) of the workpiece (604) through the connecting holes (702) of the plurality of base plates (602), the sleeve member (802) including an outer sleeve surface (804) having a lubricating coating; and

[0202] The core bolt (100, 400) is inserted (1404) into the central hole (806) of the sleeve member (802).

[0203] 71. The method of example 70, wherein, when the core bolt (100, 400) is fully engaged with the nut member (610), the method further comprises:

[0204] When the core bolt (100, 400) is fully engaged with the nut member (610), radially expanding (1406) the sleeve member (802) within the connection hole (702) passing through the plurality of base plates (602); and

[0205] When the core shaft (100, 400) is fully engaged with the nut member (610), an interference fit of the sleeve member (802) within the connecting hole (702) is provided (1408) in response to radial expansion of the sleeve member (802).

[0206] 72. The method (1500) of example 58, further comprising:

[0207] A thermoplastic polymer sealant (616) is applied (1502) to the nut member (610) such that, in conjunction with securing (902) the nut member (610), the thermoplastic polymer sealant (616) at least partially fills a cavity (822) between the nut member (610) and the blind side (608) of the workpiece (604).

[0208] 73. The method of example 58, further comprising:

[0209] A sealant cap member (618) is installed (1504) on the nut member (610) on the blind side (608) of the workpiece (604).

Claims

1. A core bolt (100, 400) of a fastener system (600, 800) for connecting a plurality of base plates (602) of a workpiece (604) having a working side (606) and a blind side (608), the core bolt comprising: a head portion (106), the head portion (106) including a concave twist feature (202); a shank (108) extending axially from the head (106) along a central longitudinal axis (110) to a distal end (104) of the core bolt (100, 400), the shank (108) including a threaded portion (102) between the distal end (104) and the head (106); and A frangible drive element (112, 412) extends from the recessed torsion feature (202) of the head (106) and projects outwardly along the central longitudinal axis (110) to define a proximal end (114) of the core bolt (100, 400).

2. The core bolt according to claim 1, wherein the core bolt (100, 400) comprises a metal material. 3 . The core bolt according to claim 2 , wherein the metal material comprises at least one of stainless steel, titanium, a titanium alloy, a cobalt-chromium alloy, and a nickel-titanium alloy.

4. The core bolt according to claim 1, wherein the head (106) comprises at least one of a flush head, a conical bottom expanded head, a protruding head, and a convex head.

5. The core bolt of claim 1 , wherein the recessed torsion feature (202) of the head (106) comprises at least one of a recessed offset cruciform drive feature, a recessed dovetail drive feature, a recessed crosshead drive feature, a recessed allen key drive feature, and a recessed flat head drive feature. The core bolt according to claim 1 , wherein: After the frangible drive element (112, 412) is separated from the head (106), the recessed torque feature (202) of the head (106) facilitates rotating the core bolt (100, 400) using at least one of an offset cross drive torque tool, a dovetail drive torque tool, a cross head drive torque tool, an allen key torque tool, and a flat head drive torque tool.

7. The core bolt of claim 1, wherein the shank (108) is opposite the concave torsion feature (202) of the head (106).

8. The core bolt of claim 1, wherein the shank (108) comprises at least one of a cylindrical body (302) and a frustoconical body (304).

9. The core bolt of claim 1 , wherein the frangible drive element (112, 412) extends from the head (106) at a central base region (116) of the recessed torsion feature (202) and is configured to be engaged by a tool used to install the core bolt (100, 400).

10. The core bolt of claim 9, wherein the tool comprises at least one of an end effector on a robotic arm, a handheld power tool, and a hand tool.

Images