Fastener

Abstract

The invention discloses a hole forming and thread forming fastener (2). The hole-forming and thread-forming fastener (2) includes a head (4) and a shank (10) defining a longitudinal axis (L). The handle (10) comprises a handle section (12) and a tip section (14). A handle section (12) extends from the head (4). A tip section (14) extends from the handle section (12) and is opposite the head (4). At least a portion of the handle section (12) is threaded. The tip section (14) is at least partially tapered and defines a tip angle (alpha). The tip angle (alpha) is at least 50 degrees.

Description

Technical Field

[0001] The present invention relates to a thread forming and hole forming fastener. The present invention also relates to a method of inserting the fastener into a workpiece and a joint. Background Art

[0002] Fasteners are used to connect components together. Fasteners may be used alone or in combination with other connection methods. A thread forming fastener is a fastener that, instead of cutting material from the workpiece to create the threads, forms the material of the workpiece to create the threads. When a thread forming fastener is inserted, no material is removed from the workpiece, or a negligible amount of material is removed. Some thread forming fasteners are also capable of forming a hole in the workpiece in which the fastener is arranged. The hole is formed simultaneously with the threads. Thread forming fasteners that can also form a hole at the same time may be referred to as thread forming and hole forming fasteners.

[0003] To insert a thread forming and hole forming fastener into a workpiece, the fastener is rotated while in contact with the workpiece, causing the workpiece to be heated. The fastener is then inserted into the workpiece. The fastener having threads is rotated while inserted into the workpiece. This forms threads on the workpiece. The quality of the resulting joint depends, among other factors, on the amount of heat supplied to the workpiece.

[0004] It is an object of the present invention to eliminate or at least alleviate the problems associated with known thread forming fasteners, whether those problems are pointed out herein or otherwise. Summary of the invention

[0005] In a first aspect of the present invention, a hole forming and thread forming fastener is provided. The hole forming and thread forming fastener includes a head and a shank defining a longitudinal axis. The shank includes a shank section and a tip section. The shank section extends from the head, and the tip section extends from the shank section and is opposite the head. At least a portion of the shank section is threaded. The tip section is at least partially tapered and defines a tip angle, the tip angle being at least 50 degrees.

[0006] Throughout this document, the term "tip angle" may be understood to refer to the internal angle of the fastener tip. The tip angle may be understood to refer to the maximum angle between two tangent lines extending through diametrically opposed points of the tip segment.

[0007] The shank section may be a cylindrical shank section. The entire shank section may be threaded. The tip section may merge into the shank section by a fillet or chamfer.

[0008] The tip angle may be other than 118 degrees.

[0009] During use, the hole forming and thread forming fastener is rotated on the surface of the workpiece to heat the workpiece. Once the workpiece is heated to a predetermined amount, the fastener is screwed into the workpiece by moving the fastener relative to the workpiece in a direction parallel to the longitudinal axis of the fastener. The fastener continues to rotate as the fastener is screwed into the workpiece. As the fastener is screwed into the workpiece, the workpiece material is molded around the threads of the shank section, thereby screwing the fastener into the workpiece. The quality of the joint produced using the fastener depends on the amount of heating of the workpiece during the insertion of the fastener. Insufficient heating of the workpiece during the insertion process produces a suboptimal joint. For example, insufficient heating of the workpiece during the insertion process may result in separation of the layers of the workpiece (when the workpiece contains multiple layers), and / or insufficient engagement between the threads of the fastener and the workpiece material. The separation of the layers of the workpiece may also be referred to as a gap.

[0010] Because the tip angle of the tip section is at least 50 degrees, the likelihood of insufficient heating of the workpiece when the fastener is inserted into the workpiece is advantageously reduced. This is due, at least in part, to the contact area between the tip section and the workpiece created by the tip angle of at least 50 degrees. Because the likelihood of insufficient heating of the workpiece when inserted into the fastener is reduced, the quality of the joint produced using the fastener is improved relative to a situation where the workpiece is insufficiently heated during the fastener insertion process.

[0011] The tip angle may be at least 70 degrees (eg when the tip is not provided with a bore).

[0012] Advantageously, the likelihood of insufficient heating of the workpiece occurring is further reduced when the tip angle is at least 70 degrees.

[0013] The tip segment may define a tip segment length. The shank segment may define a shank segment diameter. A ratio of the tip segment length to the shank segment diameter may be less than or equal to 0.6.

[0014] The ratio of the tip segment length to the shank segment diameter may be less than or equal to 0.4.

[0015] The tip angle may be less than or equal to 160 degrees.

[0016] Overheating of the workpiece during insertion may also result in a suboptimal joint. For example, overheating of the workpiece during insertion may result in separation of layers of the workpiece (when the workpiece comprises multiple layers), and / or inadequate engagement between the threads of the fastener and the workpiece material.

[0017] A tip angle of 160 degrees or less reduces the likelihood of overheating of the workpiece as the fastener is inserted into the workpiece. This is due, at least in part, to contact caused by the contact area between the tip segment and the workpiece that results from the tip angle of 160 degrees or less. Because the likelihood of overheating of the workpiece as the fastener is inserted is reduced, the quality of the joint produced using the fastener is improved relative to a situation where the workpiece overheats during fastener insertion.

[0018] Additionally, a tip angle of less than or equal to 160 degrees allows the workpiece material to bypass the fastener rather than being pushed in front of the fastener. Because the workpiece material can bypass the fastener, the likelihood of gapping during insertion of the fastener into the workpiece is advantageously reduced.

[0019] The tip angle may be at least 125 degrees. The tip angle may be less than or equal to 135 degrees.

[0020] When the tip angle is at least 125 degrees and less than or equal to 135 degrees, the likelihood of overheating or underheating is further reduced, thereby further improving the quality of the joint produced using the fastener.

[0021] The tip angle may be 130 degrees.

[0022] The head may include an internal drive geometry. The head may include an external drive geometry. The head may include a one-way drive geometry. The head may include a frangible drive portion. After the fastener is inserted into a workpiece, the frangible drive portion may be separated from the fastener.

[0023] The tip of the fastener may be conical. The tip of the fastener may be truncated cone. The tip of the fastener may be rounded.

[0024] The handle segment may include a first handle portion abutting the head.The handle segment may include a second handle portion abutting the tip segment.

[0025] The handle segment may comprise a base segment.The first handle portion may comprise a base segment.

[0026] The first handle portion may be non-threaded.The second handle portion may be threaded.

[0027] When the first shank portion is unthreaded, the resistance to fastener insertion is reduced relative to when the first shank portion is threaded. This reduces the amount of force required to insert the fastener into the workpiece. The reduced force required to insert the fastener into the workpiece advantageously reduces the amount of deflection exhibited by the workpiece during fastener insertion, thereby reducing the likelihood of play. Thus, a better quality joint may be provided when the first shank portion is unthreaded and the second shank portion is threaded.

[0028] The first handle portion may be axisymmetrical about the longitudinal axis.

[0029] The first handle portion may include one or more retaining features. During use, the one or more retaining features may engage a workpiece into which the hole forming and thread forming fastener is inserted.

[0030] The one or more retaining features may include one or more surface irregularities. The one or more surface irregularities may include a plurality of protrusions protruding from the first handle portion. The plurality of protrusions may take the form of, for example, ribs and / or hemispheres. The ribs may extend around and / or along the longitudinal axis of the handle.

[0031] When the first handle portion includes one or more retaining features, the likelihood of the fastener loosening during use is advantageously reduced, thereby producing a stronger joint.

[0032] The diameter of the first handle portion may be greater than the diameter of the second handle portion.

[0033] The head may define an undercut.

[0034] When the fastener is inserted into the workpiece, some of the workpiece material may be extruded from the opening formed in the workpiece in a direction opposite to the direction in which the fastener is inserted. When the head defines an undercut, the extruded material may advantageously be received by the undercut portion of the head. Without the undercut, the extruded material may prevent the fastener from being fully inserted. Thus, the undercut of the head allows the fastener to be fully inserted, thereby providing a stronger joint using the fastener.

[0035] The hole forming and thread forming fasteners may also include a threaded stud extending from a side of the head opposite the bottom side.

[0036] Advantageously, the threaded stud allows a component to be secured to the fastener, thereby making the fastener more versatile than if the threaded stud were not present.

[0037] The tip segment may define an undercut disposed adjacent the handle segment.

[0038] When the tip section includes an undercut, the workpiece material deforms into the undercut during fastener insertion. This creates a further interlocking area between the fastener and the workpiece. The further interlocking area increases the strength of the connection between the fastener and the workpiece compared to when no undercut is provided. Thus, the undercut allows a stronger joint to be created using the fastener.

[0039] The pitch diameter of the threads of the shank segment may be constant along at least 90% of the length of the shank segment.

[0040] The pitch diameter of the threads of the shank segment may be constant along at least 75% of the length of the shank segment.The pitch diameter of the threads of the shank segment may be constant along the entire length of the shank segment.

[0041] In a second aspect of the present invention, a method for inserting a fastener into a workpiece is provided. The method includes providing a fastener, which is a fastener according to the first aspect of the present invention, the fourth aspect of the present invention, the fifth aspect of the present invention, or the sixth aspect of the present invention. The method also includes providing a workpiece. The workpiece includes a first surface and a second surface. The second surface is opposite to the first surface. The method also includes rotating the fastener around the longitudinal axis of the fastener and contacting the fastener with the first surface of the workpiece to heat the workpiece. The method also includes screwing the fastener into the workpiece by moving the fastener and the workpiece relative to each other in a direction parallel to the longitudinal axis of the fastener so that the tip section of the fastener penetrates the first surface. The fastener does not penetrate the second surface of the workpiece.

[0042] The advantages discussed above in relation to the first aspect of the invention apply mutatis mutandis to this aspect.

[0043] The first surface of the workpiece and the second surface of the workpiece need not form part of the same material layer of the workpiece. The first surface may be referred to as an upper surface or a top surface. The second surface may be referred to as a lower surface or a bottom surface.

[0044] Threading the fastener into the workpiece may include forming threads in the workpiece with the fastener.

[0045] The method may also include providing a die. The second surface may engage the die when the fastener is screwed into the workpiece. The method may include deforming the workpiece material into the die. While the fastener is screwed into the workpiece, the workpiece material may be deformed into the die.

[0046] The method can be performed without using a mold.

[0047] When the fastener is screwed into the workpiece, the second workpiece surface engages the die, and the workpiece is advantageously better constrained than if the die were not present. The die can act on the force used to screw the fastener into the workpiece, thereby reducing deflection of the workpiece when the fastener is screwed into the workpiece compared to when the die is not provided. Workpiece deflection can, for example, cause a gap. In addition, because the force used to insert the fastener into the workpiece can be acted on by the die, the force used can be increased relative to when the die is not provided. Therefore, providing a die that engages the second workpiece surface of the workpiece advantageously provides a better quality joint.

[0048] The die may include a die recess. When the fastener is screwed into the workpiece, the second surface of the workpiece may deform into the die recess.

[0049] When the second surface of the workpiece is deformed into the recessed portion of the mold, the shape of the second surface of the workpiece can be controlled by the shape of the mold.

[0050] The mold recess may be configured so that the workpiece material does not completely fill the mold after insertion of the fastener into the workpiece is complete.

[0051] The mold recess is configured so that the workpiece material does not completely fill the mold after the fastener is inserted into the workpiece, which advantageously allows the mold to be used with a variety of different workpiece materials. In addition, the possibility of the workpiece being stuck to the workpiece is reduced.

[0052] The mould recess may be in the form of a continuous groove or a continuous channel.

[0053] The mold recess may define a mold recess volume. When the fastener is screwed into the workpiece, a certain volume of workpiece material may be displaced. The mold volume may be equal to or greater than the volume of workpiece material displaced.

[0054] A workpiece may include only a single workpiece layer.

[0055] The single workpiece layer may include a first surface and a second surface of the workpiece.

[0056] The workpiece may include a first layer and a second layer.

[0057] The first layer of the workpiece may include a first surface of the workpiece. The second layer of the workpiece may include a second surface of the workpiece.

[0058] At least one layer of the workpiece may be made of a metallic material.At least one layer of the workpiece may be made of aluminum.

[0059] Both layers of the workpiece may be made of metal materials. The first layer may be made of aluminum. The second layer may be made of aluminum. The first layer may be made of cast aluminum. The second layer may be made of aluminum plate. The second layer may be made of cast aluminum. The first layer may be made of aluminum plate.

[0060] The material of the workpiece may have a tensile strength of at least 300 MPa. The material of the workpiece may have a tensile strength of 550 MPa or less. The material of the workpiece may have a ductility of 10% or less, measured as percent elongation. The material of the workpiece may have a ductility of 5% or less, measured as percent elongation.

[0061] The first workpiece layer may include an opening through which the fastener passes prior to contact with the workpiece.

[0062] When the first workpiece layer includes an aperture through which the fastener passes prior to contact with the workpiece, the second workpiece layer may include the first surface of the workpiece.The aperture may have a diameter greater than the diameter of the threaded shank section of the thread forming and hole forming fasteners.

[0063] When the fastener is inserted into the workpiece, some of the workpiece material may be extruded from the opening formed in the workpiece in a direction opposite to the direction in which the fastener is inserted. When the first workpiece layer includes an opening through which the fastener passes before contacting the workpiece, the extruded material may be advantageously received between the fastener and the opening. In the absence of an opening, the extruded material may prevent the fastener from being fully inserted. Thus, the undercut of the head allows the fastener to be fully inserted, thereby providing a stronger joint using the fastener.

[0064] Some materials may be incompatible with the fastener. This may be because, for example, the fastener is unable to heat the material sufficiently to allow the fastener to be screwed into the material. Providing an opening through the first workpiece layer, through which the fastener passes before contacting the workpiece, allows the fastener to connect workpiece layers of different materials, including materials that are incompatible with the fastener. Thus, the method is more versatile than when no opening is provided.

[0065] The first workpiece layer may be formed from a composite material.

[0066] The first layer may be free of openings through which the thread forming and hole forming fasteners extend.

[0067] The fastener may include a threaded stud extending from a side of the head opposite the shank section of the shank. The method may also include securing a component to the threaded stud.

[0068] The rate at which the fastener rotates relative to the workpiece may be reduced at least once while the fastener is being threaded into the workpiece.

[0069] The rate at which the fastener rotates relative to the workpiece after the reduction may be a non-zero value.

[0070] Reducing the rate at which the fastener rotates relative to the workpiece allows the workpiece material to better mold around the fastener. Therefore, when the fastener is screwed into the workpiece, reducing the rate at which the fastener rotates relative to the workpiece advantageously increases the strength of the connection between the fastener and the workpiece.

[0071] When the tip segment is located in the second workpiece layer, a reduction in the rate at which the fastener rotates relative to the workpiece may occur.

[0072] The rate at which the fastener moves relative to the workpiece after the reduction may be a non-zero value.The reduction in rotational speed may occur when the tip segment has penetrated at least 25% of the second workpiece layer.

[0073] Reducing the rate at which the fastener rotates relative to the workpiece allows the workpiece material to better mold around the fastener. Much of the strength of the connection between the fastener and the workpiece is due to the connection between the fastener and the second workpiece layer. Therefore, when the tip section of the fastener is located in the second workpiece layer, reducing the rate at which the fastener rotates relative to the workpiece advantageously further increases the strength of the connection between the fastener and the workpiece.

[0074] After the fastener is threaded into the workpiece, the second surface of the workpiece may include a protrusion in which at least a portion of the tip section of the shank of the fastener is received.

[0075] In a third aspect of the present invention, a joint is provided. The joint comprises a workpiece, the workpiece comprising a first surface and a second surface. The joint further comprises a fastener according to the first aspect of the present invention, the fourth aspect of the present invention, the fifth aspect of the present invention, or the sixth aspect of the present invention. The fastener extends through the first surface and does not penetrate the second surface.

[0076] The workpiece may include a first workpiece layer. The first workpiece layer may include a first surface of the workpiece. The workpiece may include a second workpiece layer. The second workpiece layer may include a second surface of the workpiece. The fastener may at least partially penetrate the second workpiece layer. The fastener may only partially penetrate the second workpiece layer.

[0077] The fastener may be removable from the workpiece. The fastener may be non-removable from the workpiece.

[0078] The advantages discussed above in relation to the first aspect of the invention apply mutatis mutandis to this aspect.

[0079] The workpiece may include a first workpiece layer and a second workpiece layer, the first workpiece layer including a first surface, and the second workpiece layer including a second surface.

[0080] The first workpiece layer may include an opening through which the thread-forming and hole-forming fasteners extend.

[0081] The diameter of the opening may be larger than the diameter of the threaded shank section of the thread forming and hole forming fasteners.

[0082] The first workpiece layer may be formed from a composite material.

[0083] The first layer may be free of openings through which the thread forming and hole forming fasteners extend.

[0084] A workpiece may include only a single workpiece layer.

[0085] Thread forming and hole forming fasteners may also include a threaded stud extending from a side of the head opposite the shank section.

[0086] At least one layer of the workpiece may be made of a metallic material.At least one layer of the workpiece may be made of aluminum.

[0087] Both workpiece layers may be made of metal material. The first workpiece layer may be made of aluminum. The second workpiece layer may be made of aluminum. Both workpiece layers may be made of aluminum. The first workpiece layer may be made of cast aluminum. The second workpiece layer may be made of aluminum plate. The second layer may be made of cast aluminum. The first layer may be made of aluminum plate.

[0088] The material of the workpiece may have a tensile strength of at least 300 MPa. The material of the workpiece may have a tensile strength of 550 MPa or less. The material of the workpiece may have a ductility of 10% or less, measured as percent elongation. The material of the workpiece may have a ductility of 5% or less, measured as percent elongation.

[0089] The head of the thread forming and hole forming fasteners can be arranged higher than the workpiece. The head of the thread forming and hole forming fasteners can be arranged substantially flush with the workpiece.

[0090] The second surface may include a protrusion in which the tip section of the fastener is at least partially received.

[0091] In a fourth aspect of the present invention, a hole forming and thread forming fastener is provided. The hole forming and thread forming fastener includes a head and a shank defining a longitudinal axis. The shank includes a cylindrical shank section. The shank includes a tip section. The cylindrical shank section extends from the head. The tip section extends from the cylindrical shank section. The tip section is opposite the head. At least a portion of the cylindrical shank section is threaded. The fastener also includes a bore extending at least partially along the longitudinal axis to the tip section.

[0092] The term "thread forming fastener" is a term known in the art and refers to a fastener in which threads are formed by deforming the workpiece material, rather than cutting the threads into the workpiece.

[0093] The borehole may extend from the tip of the tip section along the longitudinal axis. The borehole may be a through borehole. The term "through borehole" may be understood to mean a borehole extending along the entire length of the fastener. The borehole may be cylindrical. The borehole may be a blind hole.

[0094] The entire shank section may be threaded.

[0095] During the insertion of hole forming and thread forming fasteners into a workpiece, at least some material of the workpiece is displaced by the fastener. The displaced material protrudes from one or more of the upper surface of the workpiece (i.e., the surface into which the fastener is inserted), the lower surface of the workpiece (i.e., the surface opposite the insertion surface), and one or more intermediate surfaces (i.e., the surfaces at the interface between the workpiece layers). This may result in joint defects such as separation of the workpiece layers and partial insertion of the fastener due to interference with the protruding material. These defects impair the quality of the resulting joint.

[0096] Because the fastener includes a borehole, at least some of the workpiece material is received by the borehole during and after the fastener is inserted into the workpiece. Thus, the amount of material displaced by the fastener during insertion is reduced relative to a situation where no borehole is provided, thereby reducing the likelihood of material protrusion. Providing the borehole advantageously improves the quality of the joint relative to a situation where no borehole is provided.

[0097] The tip segment may define a ring leading edge.

[0098] The ring leading edge may define a ring surface.

[0099] When the tip segment defines a leading edge of the ring, the initial contact area between the tip segment and the workpiece during insertion of the fastener into the workpiece is greater than, for example, when the tip segment defines a point. This increase in contact area advantageously heats the workpiece more quickly than a smaller contact area, thereby making the fastener insertion process faster.

[0100] Furthermore, during the insertion of the fastener, the contact area between the leading edge of the ring and the workpiece is further from the axis of rotation of the fastener than a fastener including a pointed section. Thus, at the same rotational speed, the speed of the leading edge of the ring is greater than the speed of the tip of the pointed section. This increases the amount of heat provided to the workpiece during the insertion of the fastener, thereby heating the workpiece more quickly than, for example, a fastener having a pointed section.

[0101] The ring leading edges may be non-coplanar.

[0102] The ring leading edge is non-coplanar and can be understood to mean that at least a portion of the ring leading edge is not in the same plane as another portion of the ring leading edge.

[0103] The ring leading edge may include a plurality of facets such that the ring leading edge is serrated.

[0104] Because the leading edge of the ring is non-coplanar, the amount of friction generated when inserting the fastener into the workpiece is increased. This reduces the likelihood of insufficient heating of the workpiece during fastener insertion.

[0105] The borehole may define a borehole inner diameter. The borehole may define a tapered surface section. The ring leading edge may merge into the borehole inner diameter via the tapered surface section.

[0106] The diameter of the ring leading edge may be greater than the diameter of the inner diameter of the borehole.The conical surface section may comprise a chamfered surface section and / or a rounded surface section.

[0107] The borehole may define a borehole depth. The conical surface segment may define a conical surface segment depth. The ratio of the conical surface segment depth to the borehole depth may be at least 0.1. The ratio of the conical surface segment depth to the borehole depth may be at least 0.25. The ratio of the conical surface segment depth to the borehole depth may be at least 0.5.

[0108] Because the leading edge of the ring merges into the borehole inner diameter via a tapered surface section, stresses applied to the fastener during fastener insertion and during use are more evenly distributed compared to alternative transition surfaces between the leading edge of the ring and the borehole inner diameter. More even stress distribution reduces the likelihood of fastener failure (e.g., due to fastener cracking).

[0109] The bore may define a bore inner diameter. The cylindrical shank section may define a shank diameter. A ratio of the shank diameter to the bore inner diameter may be at least 1.5.

[0110] This ratio of shank diameter to bore inner diameter advantageously provides sufficient shank material to enable the fastener to withstand the forces required during use, thereby making the fastener stronger.

[0111] The ratio of the shank diameter to the bore inner diameter may be at least 2.

[0112] The shank may define a shank length. The bore may extend along at least 25% of the shank length.

[0113] Where the bore extends along at least 25% of the length of the shank, the amount of workpiece material that can be accommodated by the bore is sufficient such that the likelihood of play during fastener insertion is substantially reduced.

[0114] The bore may extend along at least 50% of the length of the shank.

[0115] The bore may extend along at most 25% of the length of the shank. The bore may extend along at most 10% of the length of the shank.

[0116] For thinner workpieces, a shallower drill hole may be required. For thinner workpieces, the fastener displaces less workpiece material because there is less workpiece material to displace. Therefore, the depth of the drill hole can be selected based on the thickness of the workpiece. Shallower drill holes can also be used for harder and / or stronger workpieces. This is because as the hardness and strength of the workpiece increases, the likelihood of deformation during fastener insertion increases. Therefore, a drill hole extending up to 25% or up to 10% of the length of the shank provides the benefits of increased heat provided to the workpiece discussed above, while reducing the likelihood of fastener deformation.

[0117] The borehole may define a borehole surface. The borehole surface may define a plurality of surface irregularities.

[0118] When the drilled hole defines a plurality of surface irregularities, the surface irregularities interlock with the workpiece into which the fastener has been inserted. This advantageously increases the strength of the connection between the fastener and the workpiece.

[0119] The entire borehole may be cylindrical.

[0120] When the entire bore is cylindrical, the strength of the shank of the fastener is improved relative to a bore that includes a tapered section.

[0121] In a fifth aspect of the present invention, a hole forming and thread forming fastener is provided. The hole forming and thread forming fastener includes a head and a shank defining a longitudinal axis. The shank includes a shank segment. The shank includes a tip segment. The shank segment extends from the head. The tip segment extends from the shank segment. The tip segment is opposite the head. At least a portion of the shank segment is threaded. The shank segment defines a shank segment length. The tip segment defines a tip segment length. The ratio of the shank segment length to the tip segment length is at least 2.5. The tip segment includes a plurality of surface irregularities.

[0122] The ratio of the handle segment length to the tip segment length may be calculated by dividing the handle segment length by the tip segment length.

[0123] The plurality of surface irregularities may be in the form of a plurality of facets.

[0124] The plurality of surface irregularities may be in the form of a plurality of ribs.

[0125] The plurality of surface irregularities may be in the form of a plurality of facets and a plurality of ribs.

[0126] The plurality of facets may include at least three facets. The facets may each be in the form of a rounded surface segment. The facets may abut one another. The facets may be arranged in an array. The facets may be spaced apart from one another.

[0127] The plurality of ribs may include at least two ribs. The plurality of ribs may include at least three ribs. The plurality of ribs may include six ribs. The length component of the rib may extend in a radial direction (i.e., perpendicular to the longitudinal axis of the fastener). The length component of the rib may extend in a circumferential direction (i.e., around the longitudinal axis of the fastener). The rib may extend radially outward from the tip of the tip segment. The thickness and / or width of the rib may be uniform or non-uniform. The thickness of the rib may be understood to refer to the distance they protrude from the surface of the tip segment. The thickness and / or width of the rib may be minimum at or near the tip of the tip segment. The thickness and / or width of the rib may be maximum at or near the tip of the tip segment.

[0128] The tip section may be a conical tip section. The shank section may be cylindrical. The entire shank section may be threaded.

[0129] Each facet of the plurality of facets or each rib of the plurality of ribs may extend from the tip of the tip segment toward the shank segment. Each facet of the plurality of facets or each rib of the plurality of ribs may extend from the tip of the tip segment to the shank segment. Each facet of the plurality of facets may extend radially outward from the tip of the tip segment.

[0130] During use, the hole forming and thread forming fastener is rotated on the surface of the workpiece to heat the workpiece. Once the workpiece is heated to a predetermined amount, the fastener is screwed into the workpiece by moving the fastener relative to the workpiece in a direction parallel to the longitudinal axis of the fastener. The fastener continues to rotate while the fastener is screwed into the workpiece. When the fastener is screwed into the workpiece, the workpiece material is molded around the threads of the shank section, thereby screwing the fastener into the workpiece. The quality of the joint produced using the fastener depends on the amount of heating of the workpiece during the insertion of the fastener. Insufficient heating of the workpiece during the insertion process produces a suboptimal joint. For example, insufficient heating of the workpiece during the insertion process may result in separation of the layers of the workpiece (when the workpiece contains multiple layers), and / or insufficient engagement between the threads of the fastener and the workpiece material. The separation of the layers of the workpiece may also be referred to as a gap.

[0131] Because the tip segment includes a plurality of surface irregularities, the likelihood of insufficient heating of the workpiece when the fastener is inserted into the workpiece is advantageously reduced. The plurality of surface irregularities provide a discontinuous profile to the tip segment. The discontinuous profile increases the amount of friction between the tip segment of the fastener and the workpiece, thereby increasing the heat generated during the insertion of the fastener. Because the likelihood of insufficient heating of the workpiece when the fastener is inserted is reduced, the quality of the joint produced using the fastener is improved relative to a situation where insufficient heating of the workpiece occurs during the insertion of the fastener.

[0132] The plurality of facets may include six facets.

[0133] When the plurality of facets includes six facets, heating of the workpiece during fastener insertion is optimized.

[0134] The plurality of facets may include at least two facets. The plurality of facets may include at least four facets.

[0135] Each facet may each be in the form of a flat surface segment. The facets may abut one another. The facets may be spaced apart from one another.

[0136] In a sixth aspect of the present invention, a hole forming and thread forming fastener is provided. The hole forming and thread forming fastener includes a head and a shank defining a longitudinal axis. The shank includes a shank segment. The shank includes a tip segment. The shank segment extends from the head. The tip segment extends from the shank segment. The tip segment is opposite the head. At least a portion of the shank segment is threaded.

[0137] Any feature disclosed in relation to the first, fourth or fifth aspect of the invention may be combined with the sixth aspect of the invention.

[0138] In a seventh aspect of the present invention, a method for inserting a fastener into a workpiece is provided. The method includes providing a workpiece including a first workpiece layer and a second workpiece layer. The method also includes applying an adhesive to the first workpiece layer and / or the second workpiece layer. The method also includes engaging the first workpiece and the second workpiece with each other so that the adhesive is arranged between the first workpiece layer and the second workpiece layer. The method also includes providing a fastener. The fastener includes a head and a shank. The shank defines a longitudinal axis. The shank includes a shank section. The shank includes a tip section. At least a portion of the shank section is threaded. The shank section extends from the head. The tip section extends from the shank section and is opposite to the head. The method also includes rotating the fastener about the longitudinal axis and contacting the fastener with the workpiece to heat the workpiece. The method also includes screwing the fastener into the workpiece by moving the fastener and the workpiece relative to each other in a direction parallel to the longitudinal axis so that the tip section of the fastener penetrates the first workpiece layer and passes through the adhesive. The fastener at least partially penetrates the second workpiece layer.

[0139] Due to the provision of the adhesive layer, the strength of the connection between the first workpiece and the second workpiece is advantageously greater than if no adhesive was present.

[0140] The fastener may be the fastener according to the first aspect, fourth aspect, fifth aspect or sixth aspect of the present invention.

[0141] The fastener may only partially penetrate the second workpiece layer.

[0142] When the fastener only partially penetrates the second workpiece layer, the likelihood of fluid ingress via the second layer is reduced. Reducing the likelihood of fluid ingress is desirable because the presence of fluid may cause joint defects, such as oxidation. Therefore, a fastener that only partially penetrates the second workpiece layer advantageously provides a stronger joint.

[0143] Furthermore, when the fastener only partially penetrates the second workpiece layer, the tip section of the fastener is located within the second workpiece layer and does not protrude outside the workpiece. This is desirable because protruding fasteners present a risk of injuring a user and / or damaging components. Thus, fasteners that only partially penetrate the second workpiece layer advantageously provide a safer joint.

[0144] In an eighth aspect of the present invention, a method for inserting a fastener into a workpiece is provided. The method includes providing a fastener. The fastener includes a head and a shank. The shank defines a longitudinal axis. The shank includes a shank section and a tip section. The shank section is at least partially threaded. The threaded shank section extends from the head. The tip section extends from the shank section and is opposite to the head. The method also includes providing a workpiece. The workpiece includes a first surface and a second surface. The second surface is opposite to the first surface. The method also includes rotating the fastener about the longitudinal axis and contacting the fastener with the first surface of the workpiece to heat the workpiece. The method also includes moving the fastener relative to the workpiece at a rate of at least 0.5 mm / second. The fastener moves in a direction parallel to the longitudinal axis of the fastener so that the tip section penetrates the first surface of the workpiece and the fastener is screwed into the workpiece. The fastener does not penetrate the second surface of the workpiece.

[0145] The first surface of the workpiece and the second surface of the workpiece need not constitute part of the same material layer of the workpiece. The first surface may be referred to as an upper surface or a top surface. The second surface may be referred to as a lower surface or a bottom surface.

[0146] The threaded shank may be cylindrical.

[0147] Since the fastener moves relative to the workpiece at a rate of at least 0.5 mm / second in a direction parallel to the longitudinal axis of the fastener, the likelihood of overheating of the workpiece occurring is reduced. This is because the rate at which the fastener is inserted into the workpiece is sufficient so that the fastener insertion process can be completed before overheating of the workpiece occurs. Reducing the likelihood of overheating of the workpiece is desirable because overheating can result in joint defects, such as gaps. Therefore, the fastener moving relative to the workpiece at a rate of at least 0.5 mm / second in a direction parallel to the longitudinal axis of the fastener advantageously produces a better quality joint relative to the case where the fastener moves at a rate of less than 0.5 mm / second.

[0148] Furthermore, since the fastener does not penetrate the second surface of the workpiece, the likelihood of fluid ingress via the second layer is reduced. Reducing the likelihood of fluid ingress is desirable because the presence of fluid may cause joint defects, such as oxidation. Thus, a fastener that only partially penetrates the second workpiece layer advantageously provides a stronger joint.

[0149] Furthermore, because the fastener does not penetrate the second surface of the workpiece, the tip section of the fastener is located within the workpiece, rather than protruding outside the workpiece. This is desirable because protruding fasteners present a risk of injury to the user and / or damage to components. Thus, fasteners that do not penetrate the second surface of the workpiece advantageously provide a safer joint.

[0150] The rate at which the fastener moves relative to the workpiece may be reduced at least once while the fastener is being threaded into the workpiece.

[0151] The rate at which the fastener moves relative to the workpiece after the reduction may be a non-zero value.

[0152] Reducing the rate at which the fastener moves relative to the workpiece allows the workpiece material to better mold around the fastener. Therefore, when the fastener is screwed into the workpiece, reducing the rate at which the fastener moves relative to the workpiece advantageously increases the strength of the connection between the fastener and the workpiece.

[0153] The workpiece may include a first workpiece layer and a second workpiece layer. The first workpiece layer may include a first surface of the workpiece. The second workpiece layer may include a second surface of the workpiece. When the tip section of the fastener is located in the second workpiece layer, the speed at which the fastener moves relative to the workpiece may be reduced.

[0154] The rate at which the fastener moves relative to the workpiece after the reduction may be a non-zero value.

[0155] Reducing the rate at which the fastener moves relative to the workpiece allows the workpiece material to better mold around the fastener. Much of the strength of the connection between the fastener and the workpiece is due to the connection between the fastener and the second workpiece layer. Therefore, when the tip section of the fastener is located in the second workpiece layer, reducing the rate at which the fastener moves relative to the workpiece advantageously further increases the strength of the connection between the fastener and the workpiece.

[0156] The fastener may be movable relative to the workpiece in a direction parallel to a longitudinal axis of the fastener at a rate of at least 1 mm / second.

[0157] The fastener may be movable relative to the workpiece in a direction parallel to a longitudinal axis of the fastener at a rate of at least 2 mm / second.

[0158] In a ninth aspect of the present invention, a method for inserting a fastener into a workpiece is provided. The method includes providing a fastener. The fastener includes a head and a shank. The shank defines a longitudinal axis. The shank includes a shank section and a tip section. The shank section is at least partially threaded. The threaded shank section extends from the head. The tip section extends from the shank section and is opposite to the head. The method also includes providing a workpiece. The workpiece includes a first surface and a second surface. The second surface is opposite to the first surface. The method also includes rotating the fastener about the longitudinal axis and contacting the fastener with the first surface of the workpiece to heat the workpiece. The method also includes screwing the fastener into the workpiece by moving the fastener and the workpiece relative to each other in a direction parallel to the longitudinal axis so that the tip of the fastener penetrates the first surface of the workpiece. The fastener does not penetrate the second surface of the workpiece. Throughout the method, the workpiece temperature is maintained below the recrystallization temperature of the workpiece material.

[0159] The threaded shank section may be cylindrical.

[0160] Since the temperature of the workpiece is maintained below the recrystallization temperature of the workpiece material throughout the method, the fastener is better able to form threads in the workpiece than when the temperature of the workpiece exceeds the recrystallization temperature of the workpiece material. This is because below the recrystallization temperature, the ductility of the workpiece material is optimal for fastener threads to form. Above the recrystallization temperature of the material, the ductility of the workpiece material is too great for proper thread formation. Since the threads are better formed, the strength of the connection between the fastener and the workpiece is improved.

[0161] The workpiece may include a first workpiece layer and a second workpiece layer. During the entire method, the material of the first workpiece layer may not be mixed with the material of the second workpiece layer.

[0162] In a tenth aspect of the present invention, a joint is provided. The joint includes a workpiece. The workpiece includes a first workpiece layer and a second workpiece layer. The joint also includes an adhesive layer arranged between the first workpiece layer and the second workpiece layer. The joint also includes a fastener having a hole and threads formed in the workpiece. The fastener extends through the first workpiece layer, the adhesive layer, and at least partially through the second workpiece layer.

[0163] The fastener may extend only partially through the second workpiece layer. The fastener may be screwed into the first workpiece layer. The fastener may be screwed into the second workpiece layer.

[0164] The fastener may be screwed into all layers of the workpiece. The fastener may be removable from the workpiece. The fastener may not be removable from the workpiece.

[0165] In an eleventh aspect of the present invention, a joint is provided. The joint includes a workpiece. The workpiece includes a first surface and a second surface. The joint also includes a hole forming and thread forming fastener. The hole forming and thread forming fastener includes a head and a shank. The shank includes a shank section. The shank includes a tip section. At least a portion of the shank section is threaded. The shank section extends from the head. The tip section extends from the shank section. The tip section is opposite to the head. The fastener extends through the first surface. The fastener does not penetrate the second surface. The workpiece also includes a thermomechanically affected zone adjacent to an interface between the workpiece and the thread forming and hole forming fastener.

[0166] The workpiece material in the area of ​​the thermomechanically affected zone is harder than the rest of the workpiece. The harder workpiece material provides increased joint strength compared to the softer workpiece material. The harder workpiece material in the area of ​​the thermomechanically affected zone also improves the ability of the joint to withstand fatigue loads without failure.

[0167] The workpiece may include a first workpiece layer. The first workpiece layer may include a first surface of the workpiece. The workpiece may include a second workpiece layer. The second workpiece layer may include a second surface of the workpiece. The fastener may at least partially penetrate the second workpiece layer. The fastener may only partially penetrate the second workpiece layer.

[0168] The workpiece may not include a stir zone. The fastener may be removable from the workpiece. The fastener may not be removable from the workpiece.

[0169] The threaded shank section may be a cylindrical threaded shank section.

[0170] In a twelfth aspect of the invention, a joint is provided. The joint includes a workpiece. The workpiece includes only a single workpiece layer. The workpiece layer includes a first surface and a second surface. The joint also includes a hole forming and thread forming fastener. The hole forming and thread forming fastener includes a head and a shank. The shank includes a shank section. The shank includes a tip section. The shank section extends from the head. The shank section is at least partially threaded. The tip section extends from the shank section and is opposite to the head. The fastener extends through the first surface and does not extend through the second surface.

[0171] The shank section may be a cylindrical shank section. The fastener may be removable from the workpiece. The fastener may be non-removable from the workpiece.

[0172] In a thirteenth aspect of the present invention, a hole forming and thread forming fastener is provided. The hole forming and thread forming fastener includes a head and a shank defining a longitudinal axis. The shank includes a shank section. The shank includes a tip section. The shank section extends from the head. The tip section extends from the shank section. The tip section is opposite the head. At least a portion of the shank section is threaded. The head is provided with a cutting edge.

[0173] When a fastener is inserted into a workpiece to form a joint, workpiece material may be extruded from the workpiece in a direction opposite to the direction in which the fastener was inserted into the workpiece. This is undesirable because the extruded material is susceptible to corrosion, which may result in joint failure. Advantageously, the cutting feature is capable of removing any extruded workpiece material from the workpiece.

[0174] The extruded material may be referred to as excess material.

[0175] The cutting features may be provided on the underside of the head. The cutting features may be provided on the circumference of the head.

[0176] The cutting feature may be in the form of one or more ribs. The one or more ribs may include six ribs.

[0177] A component of the rib length of one or more ribs may extend in a radial direction. A component of the rib length of one or more ribs may extend in a longitudinal direction.

[0178] The cutting feature may be in the form of one or more teeth. The one or more teeth may include four teeth. At least a portion of each of the plurality of teeth may extend in a radial direction. The one or more teeth may form a portion of a radial circumferential surface of the head.

[0179] One or more teeth may extend from the bottom side of the head towards the top of the head. One or more teeth may extend from the bottom side of the head to the top of the head.

[0180] In a fourteenth aspect of the present invention, a method for inserting a fastener into a workpiece is provided. The method includes providing a fastener according to the thirteenth aspect of the present invention. The method also includes providing a workpiece, the workpiece including a first surface and a second surface. The second surface is opposite to the first surface. The method also includes rotating the fastener around the longitudinal axis of the fastener and contacting the fastener with the first surface of the workpiece to heat the workpiece. The method also includes screwing the fastener into the workpiece by moving the fastener and the workpiece relative to each other in a first direction, the first direction being parallel to the longitudinal axis of the fastener. The method also includes extruding at least some workpiece material from the workpiece in a second direction, the second direction being substantially opposite to the first direction. The method also includes removing the extruded material from the workpiece using a cutting edge of the fastener head.

[0181] Features disclosed in relation to one aspect of the invention may be combined with features of another aspect of the invention. For example, features of any of the first, fourth and / or fifth aspects of the invention may be combined with the sixth aspect of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0182] Embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

[0183] Figure 1a shows a cross-sectional side view of a fastener according to one embodiment of the present invention;

[0184] Figure 1b Shows Figure 1a A perspective view of a fastener;

[0185] Figure 2 A fastener insertion device is shown for use with any of the fasteners shown;

[0186] Figure 3 Shows Figure 2 an enlarged view of a nosepiece of a fastener insertion device;

[0187] Figure 4 Shown during fastener insertion Figure 2 A front end member of a fastener insertion device;

[0188] Figure 5 shows the use of the fastener of FIG1 and Figure 2 The fastener is inserted into the joint formed by the device;

[0189] Figure 6 A joint of a mold having a fastener insertion device is shown;

[0190] Figure 7a shows a bottom view of a fastener according to another embodiment of the present invention;

[0191] Figure 7b Shows Figure 7a a cross-sectional side view of a fastener;

[0192] Figure 8 shows a cross-sectional view of a fastener according to another embodiment of the present invention;

[0193] Fig. 9 Shows the use of Figure 8 The joints formed by the fasteners;

[0194] Fig.10 shows a cross-sectional view of a fastener according to another embodiment of the present invention;

[0195] Fig.11 shows a cross-sectional view of a joint formed using a fastener according to another embodiment of the present invention;

[0196] Fig.12 shows a cross-sectional view of a joint formed using a fastener according to another embodiment of the present invention;

[0197] Fig.13 shows a cross-sectional view of a fastener according to another embodiment of the present invention;

[0198] Fig.14 shows a cross-sectional view of a joint formed using a fastener according to another embodiment of the present invention;

[0199] Fig.15 shows a cross-sectional view of a fastener according to another embodiment of the present invention;

[0200] Fig.16 shows a cross-sectional view of a joint formed using a fastener according to another embodiment of the present invention;

[0201] Fig.17 shows a cross-sectional view of a joint formed using a fastener according to another embodiment of the present invention;

[0202] Fig.18 shows a cross-sectional view of a fastener according to another embodiment of the present invention;

[0203] Fig.19 shows a perspective view of a fastener according to another embodiment of the present invention;

[0204] Fig. 20 shows a cross-sectional side view of a fastener according to another embodiment of the present invention;

[0205] Fig.21 shows a cross-sectional view of a joint formed using a fastener according to another embodiment of the present invention;

[0206] Fig. 22 shows a cross-sectional side view of a fastener according to another embodiment of the present invention;

[0207] Fig.23 shows a cross-sectional side view of a fastener according to another embodiment of the present invention;

[0208] Fig.24 A fastener insertion device for use with any of the fasteners disclosed herein is shown;

[0209] Fig.25 Shows Fig.24 A detailed view of a fastener insertion device;

[0210] Fig.26 A joint of a mold having a fastener insertion device is shown;

[0211] Fig. 27 Shown with Figure 2 A die for use with a fastener insertion device;

[0212] Fig.28 shows a detailed view of a fastener according to another embodiment of the present invention;

[0213] Fig.29 shows a cross-sectional view of a fastener and a workpiece according to another embodiment of the present invention;

[0214] Fig.30 shows a cross-sectional view of a fastener and a workpiece according to another embodiment of the present invention;

[0215] Fig.31 A fastener according to another embodiment of the present invention is shown;

[0216] Fig.32 A fastener according to another embodiment of the present invention is shown;

[0217] Fig.33 A fastener according to another embodiment of the present invention is shown;

[0218] Fig.34A front end piece of a fastener insertion device for use with any of the fasteners disclosed herein is shown; and

[0219] Fig.35 A side view of a fastener according to another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0220] Figure 1a and Figure 1b A fastener 2 is depicted. The fastener 2 includes a head 4. The head 4 includes an underside 15. The fastener 2 includes a shank 10. The shank 10 extends from the underside 15 of the head 4. Figure 1b As can be seen, the head 4 includes a drive geometry 6. The periphery of the drive geometry 6 defines a discontinuous profile. During use, the drive geometry 6 engages with a fastener insertion device, as will be discussed in more detail below. The drive geometry 6 is an external drive geometry. In some embodiments, the drive geometry 6 can be an internal drive geometry. In some embodiments, the drive geometry 6 can be a snap-on drive geometry.

[0221] The head 4 defines an undercut 8. The undercut 8 is disposed adjacent to and extends around the shank 10. The undercut 8 is capable of receiving material from a workpiece during use, as will be discussed in more detail below. In some embodiments, the undercut 8 need not be present. In the absence of the undercut 8, the bottom side 15 of the head 4 may be substantially flat.

[0222] The handle 10 includes a handle section 12. The handle section 12 includes a base section 11. The base section 11 of the handle section 12 extends from the head 4 of the fastener 2. The handle 10 includes a tip section 14. The base section 11 is generally arranged in the undercut 8 of the head 4. However, in some embodiments, a portion of the base section 11 may extend beyond the bottom side 15 of the head 4. In such an embodiment, the base section may taper toward the handle section 12 (as shown). The handle section 12 defines a handle section diameter SD. The handle section diameter SD may be referred to as a minor diameter. The handle section diameter SD may not include the diameter of the base section 11. The handle section diameter SD is determined by, for example, the required connection strength of the fastener. The diameter of the handle section 12 may be at least 2 mm. The diameter of the handle section 12 may be less than or equal to 10 mm. The diameter of the handle section 12 may be at least 3 mm. The diameter of the handle segment 12 can be less than or equal to 8 mm. The diameter of the handle segment 12 can be 4 mm, so that the fastener 2 is an M4 fastener. The diameter of the handle segment 12 can be 5 mm. The diameter of the handle segment 12 does not need to be an integer. For example, the diameter of the handle segment 12 can be 4.5 mm. The handle segment 12 defines a longitudinal axis L.

[0223] The shank segment 12 is threaded. Therefore, the shank segment 12 can be referred to as a threaded shank segment. The threads of the shank segment 12 define a thread diameter TD. The thread diameter TD can be referred to as a major diameter. The thread diameter TD is typically constant along the length of the shank segment. In some embodiments, the thread diameter TD of the shank segment 12 can be substantially constant along at least 50% of the length of the shank segment. In some embodiments, the thread diameter TD can be substantially constant along at least 75% of the length of the shank segment. In some embodiments, the thread diameter TD can be substantially constant along at least 90% of the length of the shank segment. In some embodiments, the threads of the shank segment 12 can include a tapered segment adjacent to the tip segment 14. The shank segment 12 is generally cylindrical. In Figure 1a In the embodiment of the present invention, the entire shank section is shown to be threaded, however, in some embodiments, at least a portion of the shank section 12 can be threaded. The fastener 2 can be made of any suitable material. For example, the fastener 2 can be made of steel. The fastener 2 can be provided with a coating. The coating can be, for example, a zinc-nickel coating.

[0224] The tip segment 14 extends from the shank segment 12. In some embodiments, the tip segment 14 may be merged into the shank segment 12 by a fillet. In some embodiments, the tip segment 14 may be merged into the shank segment 12 by a chamfer. The tip segment 14 is arranged at an end of the shank segment 12 opposite to the head 4. The tip segment 14 defines a tip segment length TL. In some embodiments, the ratio of the tip segment length TL to the thread diameter TD of the shank segment 12 may be less than or equal to 0.6. In some embodiments, the ratio of the tip segment length TL to the thread diameter TD of the shank segment 12 may be less than or equal to 0.4. The ratio of the tip segment length TL to the thread diameter TD of the shank segment 12 may be calculated by dividing the tip segment length TL by the thread diameter TD. The ratio of the tip segment length TL to the thread diameter TD may be selected based on, for example, the thickness of the workpiece as a whole and / or the thickness of a separate layer of the workpiece. The ratio of the tip segment length TL to the thread diameter TD may be proportional to the thickness of the workpiece.

[0225] The tip segment 14 is conical. The tip segment 14 defines a tip angle α. The term tip angle may be understood to refer to the internal angle of the tip of the tip segment 14. The tip angle α is at least 50°. The tip angle α may be at least 70°. The tip angle α may be less than or equal to 160°. The tip angle α may be at least 125° and less than or equal to 135°. The tip angle α may not be 118°. In the illustrated embodiment, the tip segment 14 is conical. However, in other embodiments, the tip segment 14 may be any other conical shape, such as a truncated cone or a rounded corner. In the case where the tip segment 14 is a truncated cone or any other conical shape, the tip angle α is the angle between diametrically opposed points on the conical surface of the tip segment 14. Regardless of the shape of the tip segment 14, the tip angle α is the maximum angle defined between two tangents extending through diametrically opposed points of the tip segment 14. The points through which the tangents extend are located at corresponding points along the longitudinal axis L. In the case where the tip segment 14 is rounded, the tip segment can be generally dome-shaped. When the tip segment 14 is dome-shaped, the dome can be a pointed dome. In the case where the tip segment 14 is rounded, the radius of the tip segment can be at least 2 mm. The radius of the tip segment 14 can be equal to or less than 15 mm. The radius of the tip segment 14 can be at least 5 mm. The radius of the tip segment can be less than or equal to 10 mm. The tip segment 14 defines a tip 19. The tip 19 defines the endpoint of the tip segment 14. The tip 19 is in the form of a point. In other embodiments, such as when the tip segment 14 is truncated cone-shaped, the tip 19 can be in the form of a flat surface segment.

[0226] Fastener 2 is a hole forming and thread forming fastener. The term thread forming fastener is a term known in the art and refers to a fastener that forms threads by deforming the workpiece material, rather than cutting threads in the workpiece (which would remove workpiece material). Fastener 2 forms threads in the workpiece (rather than cutting threads) by the geometry of the threads of the shank section 12 and by the process of inserting the fastener into the workpiece, as will be discussed in more detail below. The term hole forming fastener is a term known in the art and refers to a fastener that forms a hole by deforming the workpiece material, rather than cutting a hole in the workpiece.

[0227] Figure 2 An insertion device 16 is shown that is capable of inserting a fastener 2 into a workpiece 17. In some embodiments, a handheld fastener insertion device can be used to insert the fastener 2 into the workpiece 17. Figure 2, the workpiece 17 includes a first workpiece layer 18 and a second workpiece layer 20. The first workpiece layer 18 may be referred to as a top layer of the workpiece 17. The second workpiece layer 20 may be referred to as a bottom layer of the workpiece 17. The first workpiece layer 18 defines a first surface 34 of the workpiece 17. The first surface 34 may be referred to as a top surface of the workpiece 17. The second workpiece layer 20 defines a second surface 36 of the workpiece 17. The second surface 36 of the workpiece 17 is opposite to the first surface 34 of the workpiece 17. The second surface 36 may be referred to as a bottom surface of the workpiece 17. In some embodiments, the workpiece 17 may include only a single workpiece layer. In the case where the workpiece 17 includes only a single workpiece layer, the single workpiece layer includes the first surface 34 and the second surface 36 of the workpiece. In other embodiments, the workpiece 17 may include three, four, or more workpiece layers. In the case where the workpiece 17 includes more than two workpiece layers, the second workpiece layer 20 may still be the bottom workpiece layer. The layer arranged between the first workpiece layer 18 and the second workpiece layer 20 may be referred to as an intermediate layer.

[0228] The first workpiece layer 18 and the second workpiece layer 20 can be made of any suitable material. The first workpiece layer 18 and the second workpiece layer 20 can be made of a metal material. In the present embodiment, the first workpiece layer 18 and the second workpiece layer 20 are made of aluminum. The first workpiece layer 18 is made of cast aluminum. The second workpiece layer 20 is made of an aluminum plate. In some embodiments, the first workpiece layer 18 can be made of an aluminum plate. In some embodiments, the second workpiece layer 20 can be made of cast aluminum. In the case where one or both of the first workpiece layer 18 and the second workpiece layer 20 are made of cast aluminum, the diameter of the shank section 12 can be greater than the diameter of the other material. This is because the fastener 2 is usually inserted into the flange portion of the workpiece, and the flange of the cast workpiece is usually larger than the flange of, for example, a plate workpiece. Therefore, the cast workpiece provides more workpiece material for the fastener 2 to be inserted. The material of the first workpiece layer 18 and / or the second workpiece layer 20 can have a tensile strength of at least 300 MPa. The material of the first workpiece layer 18 and / or the second workpiece layer 20 can have a tensile strength equal to or less than 550 MPa. In some embodiments, the material of the first workpiece layer 18 and / or the second workpiece layer 20 may have a tensile strength of at least 100 MPa. In some embodiments, the material of the first workpiece layer 18 and / or the second workpiece layer 20 may have a tensile strength equal to or less than 1000 MPa. The material of the first workpiece layer 18 and / or the second workpiece layer 20 may have a ductility equal to or less than 10%, measured as a percentage elongation. The material of the first workpiece layer 18 and / or the second workpiece layer 20 may have a ductility equal to or less than 5%, measured as a percentage elongation.

[0229] The insertion device 16 includes a shaft 22. The shaft 22 is driven by a first actuator 24 and a second actuator 25. The first actuator 24 is an electric motor. In some embodiments, the first actuator 24 can be a pneumatic cylinder. In some embodiments, the first actuator 24 can be an air-oil actuator or an electric-oil actuator. The first actuator 24 is configured to move about the longitudinal axis ( Figure 2 The second actuator 25 is a pneumatic cylinder. In some embodiments, the second actuator 25 can be an electric motor. In some embodiments, the second actuator 25 can be a gas-oil actuator or an electric-oil actuator. The second actuator 25 is configured to move the shaft 22 in an axial direction, which is a direction parallel to the longitudinal axis of the shaft. The shaft 22 is capable of engaging with the driving geometry 6 of the fastener 2 so that rotation of the shaft 22 also causes rotation of the fastener 2. The insertion device 16 includes a front end piece 26. Before being inserted into the fastener, the fastener 2 is received in the front end piece 26.

[0230] In some embodiments, the fastener insertion device 16 does not support the workpiece 17 on the second workpiece surface when inserting the fastener into the workpiece. This may be referred to as single-sided insertion. Figure 2 A fastener insertion apparatus 16 is shown that performs a single-sided insertion. The method of inserting the fastener 2, or any other fastener disclosed herein, into a workpiece may be a single-sided insertion method.

[0231] The fastener insertion device 16 may include a C-shaped frame ( Figure 2 ). The C-frame may also be referred to as a C-clamp. A C-frame may be provided in a manner where the workpiece 17 is supported on a first workpiece surface and a second workpiece surface while the fastener is inserted into the workpiece. This may be referred to as a double-sided insertion. Thus, the method of inserting the fastener 2 or any other fastener disclosed herein into a workpiece may be a double-sided insertion method. Double-sided insertion allows the force used to insert the fastener 2 into the workpiece 117 to be effective. This results in reduced deflection of the workpiece compared to single-sided insertion. Reducing workpiece deflection is advantageous because reducing workpiece deflection reduces the likelihood of workpiece damage and / or joint defects (e.g., gaps).

[0232] Figure 2 The insertion device 16 is shown immediately before the fastener 2 is inserted into the workpiece 17. The insertion device 16 can be any suitable commercially available insertion device. For example, the insertion device 16 can be an Atlas Copco IAS GmbH available from Atlas Copco, Geretsried, Germany. system.

[0233] Figure 3The front end piece 26 of the fastener insertion device 16 is shown prior to insertion of a fastener 2. The shaft 22 includes an end portion 28. The end portion 28 of the shaft 22 includes a bore 30. The bore 30 extends into the end portion 28. The bore 30 provides the end portion 28 of the shaft 22 with a fastener engagement portion 32. The geometry of the fastener engagement portion 32 is complementary to the drive geometry 6 of the fastener 2. The fastener engagement portion 32 is configured to engage with the drive geometry 6 of the head 4 of the fastener 2. Figure 3 2, the head 4 of the fastener 2 is received in the bore 30 of the end portion 28 of the shaft 22. Therefore, rotation of the shaft 22 also causes rotation of the fastener 2. Similarly, movement of the shaft 22 in the axial direction causes the fastener 2 to move along its longitudinal axis ( Figure 3 When the fastener 2 is received by the fastener engagement portion 32, the longitudinal axis of the fastener 2 is coaxial with the longitudinal axis of the shaft 22.

[0234] A method of inserting a fastener 2 into a workpiece 17 will now be described. Although the method will be described with respect to the fastener 2, the method is applicable to all embodiments of the fasteners described herein. Figure 3 Starting from the position shown, the front end 26 is brought into engagement with the first surface 34 of the workpiece 17. The shaft 22 (and therefore the fastener 2) is then moved about its longitudinal axis ( Figure 3 17 (not shown) is rotated so that the fastener rotates about its longitudinal axis. The shaft 22 rotates at a speed of, for example, 3000 rpm. In some embodiments, the shaft 22 may rotate at a speed of at least 500 rpm and / or equal to or less than 12000 rpm. In some embodiments, the shaft 22 may rotate at a speed of at least 1000 rpm and / or equal to 6000 rpm. In some embodiments, the shaft may rotate at a speed equal to or less than 9000 rpm. In some embodiments, the shaft 22 may rotate at a speed of 6000 rpm. In some embodiments, the shaft 22 may rotate at a speed of 9000 rpm. The speed at which the shaft 22 rotates may be determined by, for example, the hardness of the material from which the workpiece 17 is made. The speed required for the shaft 22 to rotate generally increases as the hardness of the material from which the workpiece 17 is made increases. Although Figure 3The fastener 2 is shown spaced apart from the workpiece when the shaft 22 begins to rotate, but in some embodiments, the fastener 2 may be brought into contact with the workpiece 17 before the shaft 22 begins to rotate. While the shaft 22 rotates, the shaft 22 moves in the axial direction until the tip 19 of the fastener 2 contacts the first surface 34 of the workpiece 17. Once the tip 19 contacts the first surface 34 of the workpiece 17, the movement of the shaft 22 in the axial direction (and therefore the movement of the fastener 2 in the axial direction) is paused. While the movement of the shaft 22 is paused, the shaft may apply a load to the fastener 2. The load applied by the shaft 22 to the fastener 2 may extend in the axial direction. Therefore, the load applied by the shaft 22 to the fastener 2 may be referred to as an axial load. The load applied by the shaft 22 to the fastener 2 may be 250N. While the fastener 2 contacts the first surface 34 of the workpiece 17, the shaft 22 continues to rotate, and therefore the fastener 2 continues to rotate. This heats the workpiece 17. This is because of the friction between the tip section 14 of the fastener 2 and the first surface 34 of the workpiece 17. When the shaft 22 applies an axial load to the fastener 2 , the magnitude of the friction force generated between the tip section 14 of the fastener 2 and the first surface 34 of the workpiece 17 is greater than when the fastener is not axially loaded.

[0235] The shaft 22 continues to rotate, and therefore the fastener 2 continues to rotate, until a predetermined amount of heat is provided to the workpiece 17. Heating the workpiece 17 softens the material of the workpiece 17 (reduces its hardness). However, the material of the workpiece 17 does not melt. Throughout the process of fastener insertion, the workpiece 17 remains below the recrystallization temperature of the workpiece material. The recrystallization temperature of the material is typically 40% to 50% of the melting temperature of the material. The recrystallization temperature can vary depending on, for example, whether the material undergoes any cold deformation (i.e., deforming the material without raising the temperature of the material). The recrystallization temperature of aluminum alloys is typically 340°C to 400°C, and the recrystallization temperature of magnesium alloys is typically 300°C to 400°C. Since the material of the workpiece 17 remains below the recrystallization temperature, the fastener insertion process is a warm forming process. Since the material of the workpiece 17 remains below the recrystallization temperature during the fastener insertion process, the material of the workpiece 17 is less soft than when the material of the workpiece is above the recrystallization temperature. This advantageously allows the fastener 2 to form threads in the workpiece 17 during the fastener insertion process. Throughout the fastener insertion process, the material of the first workpiece layer 18 and the material of the second workpiece layer 20 will not mix with each other. However, the material of the first workpiece layer 18 and the material of the second workpiece layer 20 may mix to a lesser extent.

[0236] After providing the predetermined amount of heat to the workpiece 17, the shaft (and therefore the fastener 2) is moved in the axial direction so that the fastener 2 enters the workpiece 17. The load applied to the fastener 2 as the fastener 2 enters the workpiece 17 is at least 500N. In some embodiments, the load applied to the fastener 2 as the fastener 2 enters the workpiece 17 is less than or equal to 20kN. In some embodiments, the load applied to the fastener 2 as the fastener 2 enters the workpiece 17 is at least 2kN. In some embodiments, the load applied to the fastener 2 as the fastener 2 enters the workpiece 17 is less than or equal to 15kN. In some embodiments, the load applied to the fastener 2 as the fastener 2 enters the workpiece 17 is less than or equal to 10kN. In some embodiments, the load applied to the fastener 2 as the fastener 2 enters the workpiece 17 is less than or equal to 5kN. In some embodiments, the load applied to the fastener 2 as the fastener 2 enters the workpiece 17 is at least 1kN. In some embodiments, the load applied to the fastener 2 as the fastener 2 enters the workpiece 17 is at least 3kN. As the number of workpiece layers increases, higher loads may be required. In addition, the load used may be proportional to the hardness of the material from which the workpiece 17 is made. Other factors may be considered when determining the load applied to the fastener 2 during this stage of the fastener insertion process. This causes the fastener 2 to be screwed into the workpiece 17. Figure 4 The insertion device 16 and the fastener 2 are shown when the tip 19 of the fastener 2 is in contact with the first surface 34 of the workpiece 17. The rate at which the shaft 22 (and therefore the fastener 2) moves in the axial direction is at least 0.5 mm / second. Since the shaft 22 moves at a rate of at least 0.5 mm / second, the possibility of overheating the workpiece during the fastener insertion process is reduced. This is because moving the fastener 2 at this rate ensures that the fastener insertion process is completed before the workpiece 17 overheats. In the case where the temperature of the workpiece exceeds the recrystallization temperature of the material from which the workpiece is made, the workpiece 17 can be considered to be overheated. In some embodiments, the shaft 22 can move in the axial direction at a rate of at least 1 mm / second. In some embodiments, the shaft 22 can move in the axial direction at a rate of at least 2 mm / second. The rate at which the shaft 22 moves in the axial direction can be at least partially determined by the ductility of the material from which the workpiece 17 is made. For workpiece materials with higher ductility, the rate at which the shaft 22 moves in the axial direction can be higher. As the ductility of the material from which the workpiece 17 is made decreases, the rate at which the shaft 22 moves in the axial direction can be lower. The rate at which the shaft 22 moves in the axial direction may also be determined, at least in part, by the amount of heat provided by the fastener 2 to the workpiece 17. The more heat the fastener provides to the workpiece 17, the faster the rate at which the shaft 22 moves in the axial direction.

[0237] In some embodiments, when the fastener 2 is screwed into the workpiece 17, the rate at which the shaft 22 moves in the axial direction can be reduced at least once. The reduction in speed can be such that the speed of the shaft 22 in the axial direction after the reduction is a non-zero value. The reduction in the rate at which the shaft 22 moves in the axial direction can be such that the speed of the shaft 22 in the axial direction after the reduction is at least 50% of the speed of the shaft in the direction before the reduction. The reduction in the rate at which the shaft 22 moves in the axial direction can be such that after the reduction, the distance the shaft moves in the axial direction for each rotation of the shaft is equal to or less than the pitch of the thread of the shank section 12 of the fastener 2. Advantageously, this reduces the possibility of the thread formed by the fastener 2 in the workpiece 17 being stripped. Stripping of the thread is undesirable because it can result in, for example, poor joint strength. The term "pitch" can be understood to refer to the distance between corresponding points of the thread of the shank section. The rate at which the shaft 22 moves in the axial direction is such that the distance moved in the axial direction with each rotation of the shaft is less than the pitch of the threads of the shank section 12 of the fastener 2, and the material of the workpiece 17 is preferably sufficiently soft that the threads are reformed in the workpiece with each rotation of the shaft 22 (and therefore each rotation of the fastener 2). A reduction in the speed of the shaft 22 in the axial direction may occur when the tip 19 of the fastener 2 is located in the second workpiece layer 20. A reduction in the speed of the shaft 22 in the axial direction may occur when the tip 19 contacts the second workpiece layer 20. For example, the position of the tip 19 may be determined by monitoring the position of the shaft 22 and determining the amount that the shaft has moved in the axial direction.

[0238] When the fastener 2 moves in the axial direction, the material of the workpiece 17 is deformed around the tip section 14 and around the shank section 12 of the fastener 2. The material of the workpiece 17 is deformed into the threads of the shank section 12. Therefore, threads are formed in the material of the workpiece 17 so that the fastener 2 is screwed into the workpiece 17. In addition, an opening (or hole) for receiving the fastener 2 is formed in the workpiece 17. The shaft 22 continues to move in the axial direction, and thus the fastener 2 continues to move in the axial direction until the tip section 14 is located within the second workpiece layer 20. Before the tip 19 of the fastener 2 penetrates the second surface 36 of the workpiece 17, the movement of the shaft 22 in the axial direction stops, and thus the movement of the fastener 2 in the axial direction stops. Therefore, once the fastener insertion process is completed, the tip 19 of the fastener 2 is located within the second workpiece layer 20 of the workpiece 17. In addition, once the fastener insertion process is completed, the bottom side 15 of the head of the fastener 2 contacts the first surface 34 of the workpiece 17.

[0239] In some embodiments, when the fastener 2 is screwed into the workpiece 17, the speed at which the shaft 22 rotates around its longitudinal axis can be reduced at least once, and thus the speed at which the fastener 2 rotates around its longitudinal axis can be reduced at least once. The reduction in the rotational speed can be such that the rotational speed of the shaft 22 after the reduction is a non-zero value. The reduction in the rotational speed of the shaft 22 is such that the rotational speed of the shaft 22 after the reduction is at least 50% of the rotational speed of the shaft 22 before the reduction. In some embodiments, the reduction in the rotational speed of the shaft 22 is such that the rotational speed of the shaft 22 after the reduction is at least 30% and / or less than or equal to 70% of the rotational speed of the shaft 22 before the reduction. The reduction in the rotational speed of the shaft 22 may occur when the tip 19 of the fastener 2 is located in the second workpiece layer 20. The reduction in the rotational speed of the shaft may occur when the tip 19 contacts the second workpiece layer 20. The rotational speed of the shaft 22 after the reduction may be, for example, 300 rpm.

[0240] As the rotational speed decreases, the heat provided to the workpiece 17 is reduced relative to the heat provided to the workpiece 17 before the decrease. This causes the material temperature of the workpiece 17 to also decrease. As the material temperature of the workpiece 17 decreases, the torque required to rotate the shaft 22 at a constant or approximately constant rotational speed increases. In addition, when the bottom side 15 of the head 4 of the fastener 2 is in contact with the first surface 34 of the workpiece 17, the torque required to rotate the shaft 22 at a constant or approximately constant rotational speed increases. Throughout the fastener insertion process, the torque required to rotate the shaft 22 is monitored. When the torque required to rotate the shaft 22 reaches a predetermined value, the rotation of the shaft 22 is stopped, and therefore the rotation of the fastener 2 is stopped. The predetermined torque value at which the shaft 22 stops rotating can be at least 3Nm. The predetermined torque value at which the shaft 22 stops rotating can be less than or equal to 30Nm. The predetermined torque value at which the shaft stops rotating can be at least 10Nm. The predetermined torque value at which the shaft 22 stops rotating can be less than or equal to 20Nm. The predetermined torque value at which the shaft 22 stops rotating can be 10Nm. The magnitude of the predetermined torque may be determined by, for example, the desired connection strength and / or the material from which the workpiece 17 is made.

[0241] Figure 5A joint 38 formed by the process of inserting a fastener 2 into a workpiece 17 is shown. The head 4 of the fastener 2 is higher than the workpiece 17. In other words, the head 4 protrudes beyond the first surface 34 of the workpiece 17. In some embodiments, the head 4 may be flush with the workpiece. If the head is substantially coplanar with the first surface 34 of the workpiece 17, the head 4 is flush with the workpiece 17. The fastener 2 is removable from the joint 38. In some embodiments, the fastener 2 may not be removable. Whether the fastener 2 is removable from the joint 38 depends on the function of the fastener during use. The bottom side 15 of the head 4 of the fastener 2 engages the first surface 34 of the workpiece 17. The tip section 14 of the fastener 2 is located within the second workpiece layer 20. The tip section 14 has not yet penetrated the second surface 36 of the workpiece 17. Therefore, the tip section 14 of the fastener 2 has only penetrated partially into the second workpiece layer 20. As a result of the fastener insertion process, the second workpiece layer 20 now includes a protrusion 40. This is because the fastener 2 displaced a certain volume of the material of the workpiece 17. The protrusion 40 extends from the second surface 36 of the workpiece 17. The tip 19 of the fastener 2 is located within the protrusion 40. No portion of the tip section 14 of the fastener 2 extends through the second surface 36 of the workpiece 17.

[0242] Since the temperature of the workpiece 17 does not exceed the recrystallization temperature of the material of the workpiece 17 during the entire process of fastener insertion, the joint 38 includes a thermo-mechanically affected zone (TMAZ). The thermo-mechanically affected zone is characterized by the material of the workpiece 17 being subjected to heating and mechanical shearing during the fastener insertion process. The thermo-mechanically affected zone is disposed adjacent to the interface between the workpiece 17 and the fastener 2.

[0243] The quality of the joint produced using the insertion process depends on the heat provided to the workpiece 17 during the fastener insertion process. Insufficient or excessive heating of the workpiece during the fastener insertion process can result in joint defects. Examples of such joint defects are insufficient engagement of the threads of the shank section 12 of the fastener 2 with the workpiece 17, or separation of the first workpiece layer 18 from the second workpiece layer 20. The separation between the first workpiece layer 18 and the second workpiece layer 20 can be referred to as a gap. The gap is undesirable because environmental substances (such as water) can enter the joint and can damage the joint. The heat provided to the workpiece 17 during the fastener insertion process depends on the tip angle α of the tip section 14 of the fastener 2. The tip angle α of the fastener 2 of the present embodiment can be optimized within a range of at least 50° to provide optimal heat to the workpiece 17. The optimal tip angle α depends on at least the ductility of the material of the workpiece 17, the hardness of the material of the workpiece 17, the insertion rate of the fastener during the fastener insertion process, and the axial movement rate of the fastener during the fastener insertion process. This reduces the likelihood of under-heating or over-heating of the workpiece 17 during fastener insertion relative to situations where the fastener has a tip angle α outside the range of the tip angle α of the present embodiment.

[0244] In some embodiments, the fastener insertion process may include applying an adhesive to the first workpiece layer 18 and / or the second workpiece layer 20. Before the workpiece 17 is provided to the fastener insertion device 16, the adhesive is applied to the first workpiece layer 18 and / or the second workpiece layer 20. The adhesive can be applied in the form of a liquid paste layer or a film layer. The adhesive is applied to the first workpiece layer 18 and the second workpiece layer 20 in the area where the fastener 2 is to be inserted. The first workpiece layer 18 and the second workpiece layer 20 are then joined to each other. Once the first workpiece layer 18 has been joined to the second workpiece layer 20, the adhesive is arranged between the first workpiece layer 18 and the second workpiece layer 20. Then continue the fastener insertion process as described above, wherein the fastener passes through the adhesive layer. When the adhesive is applied, the joint produced by the fastener insertion process includes an adhesive layer arranged between the first workpiece layer and the second workpiece layer.

[0245] The fastener insertion device 16 does not require a mold. When the fastener insertion device 16 does not include a mold, the method of inserting the fastener 2 into the workpiece 17 can be a single-sided insertion or a double-sided insertion. For example, in the case where the workpiece 17 is a box-shaped section, or in the case where the fastener insertion device cannot approach the point on the workpiece where the fastener 2 will be inserted from both sides, not using a mold can be particularly useful. In these cases, a single-sided insertion can be appropriate. However, a double-sided insertion method can also be used. For thicker workpieces (e.g., a total workpiece thickness of at least 6 mm), not using a mold can also be beneficial. This is because thicker workpieces can better accommodate the volume occupied by the fastener.

[0246] Fig.24 The fastener insertion device 16 is shown without a die. Using the fastener insertion device 16, the second surface of the workpiece (not shown) is supported on the lower arm 29 of the C-frame 35. Thus, Fig.24 The fastener insertion device 16 allows for double-sided insertion of fasteners. Fig.25 A detailed view of the lower arm 29 of the C-frame 35 is shown. The lower arm 29 of the C-frame 35 includes a die holder 37. A die bar (not shown) is receivable in the die holder 37. Whether or not the die is received in the die holder 37, double-sided insertion of the fastener can be performed.

[0247] In some embodiments, a mold may be provided during the fastener insertion process. Figure 6 Another embodiment of a joint 138 is shown having a die 135. The die 135 forms part of a fastener insertion device (not shown) and may be provided, for example, on the opposite side of a C-clip (or other fixture) from a punch of the fastener insertion device. The die may be received in a die holder of the lower arm of the C-clip.

[0248] The mold 135 defines a mold recess 137. The mold recess 137 defines a mold recess volume. The mold recess 137 includes a bottom surface 139. The mold recess 137 includes a sidewall 141. In the illustrated embodiment, the mold recess 137 is generally cylindrical. In other embodiments, the mold recess 137 can be any suitable shape. For example, the mold recess can be a truncated cone.

[0249] During the fastener insertion process, the die 135 engages with the second surface 136 of the workpiece 117. The die 135 engages with the second surface 136 of the workpiece 117 throughout the fastener insertion process. The die 135 is brought into contact with the second surface 136 of the workpiece 117 before the fastener 2 contacts the workpiece 117. As described above, when the fastener 2 is inserted into the workpiece 117, at least some material of the workpiece 117 is displaced. With the die 135 provided, the displaced material of the workpiece 117 is deformed into the die recess 137. The volume of the die recess 137 may be equal to or greater than the volume of the workpiece material displaced during the fastener insertion process.

[0250] Fig.26 An alternative mold 235 is shown. Mold 235 is similar to mold 135. Mold 235 differs from mold 135 in that mold recess 237 does not include a bottom surface. Mold recess 237 includes sidewalls 241. Because mold recess 237 does not include a bottom surface, deformation of the workpiece material in the direction of insertion of the fastener into the workpiece is less restricted than in mold recesses that include a bottom surface. Deformation of the workpiece material is molded by sidewalls 241 of mold recess 237. The mold may include a surface arranged at or toward the bottom end of the recess, which, when in use, is spaced apart from the second surface of the workpiece. With this arrangement, the second surface does not contact the bottom surface during fastener insertion.

[0251] Fig. 27 Another alternative mold 335 is shown. The mold 335 can be used with Figures 2 to 4 The die 335 is used together with the fastener insertion device 2 shown. The die 335 is in the form of a die table. The die table 335 includes a plurality of die recesses 337. When the die 335 is used to insert a fastener into a workpiece, the front end of the fastener insertion device (not shown) is positioned above one of the die recesses 337. The die 337 allows multiple fasteners to be inserted into different positions of a workpiece (not shown) without moving the workpiece. In some embodiments, the die recesses 337 of the die table can be in the form of a continuous channel or a continuous groove extending along the length or width of the die table.

[0252] In some embodiments, a fastener may include a plurality of surface irregularities. Figure 7a and Figure 7bThis embodiment of a fastener 102 is shown. Similar reference numerals used for fastener 2 are used for fastener 102. In this embodiment, the tip segment 114 is depicted as a truncated cone. However, in other embodiments, the tip segment can be conical. Since the tip segment 114 is a truncated cone, the tip 119 of the tip segment defines a flat surface segment.

[0253] The fastener 102 differs from the fastener 2 of FIG. 1 in that the tip section 114 of the fastener 102 includes a plurality of surface irregularities 142 (in Figure 7a Only one of them is marked in the figure). In the illustrated embodiment, the surface irregularity is in the form of facets 142. In the illustrated embodiment, the plurality of facets 142 includes six facets. However, in other embodiments, the plurality of facets 142 may include any suitable number of facets. In some embodiments, the plurality of facets 142 may include at least two facets. In some embodiments, the plurality of facets 142 may include at least four facets. In some embodiments, the plurality of facets 142 may include less than or equal to nine facets. In some embodiments, the plurality of facets 142 may include less than or equal to eight facets. The optimal number of facets for the plurality of facets 142 may be determined by, for example, the desired fastener insertion time (i.e., the time required to insert the fastener into the workpiece) and the material properties of the workpiece into which the fastener 102 is to be inserted. As the number of facets increases, the amount of heat provided to the workpiece during the fastener insertion process also increases. When the workpiece is made of aluminum, the optimal number of facets is preferably six. This is because the possibility of overheating or insufficient heating of the workpiece is minimized. The plurality of facets 142 are arranged in an array. Thus, the plurality of facets 142 are distributed around the longitudinal axis of the fastener 2. In the illustrated embodiment, the plurality of facets 142 are adjacent to each other. However, in other embodiments, the facets of the plurality of facets 142 may be spaced apart from each other. Where the facets of the plurality of facets 142 are spaced apart from each other, rounded surface segments may be arranged between the facets. Each facet of the plurality of facets 142 is in the form of a flat surface segment. However, in other embodiments, each facet of the plurality of facets 142 may be in the form of a rounded surface segment.

[0254] Figure 7bA cross-sectional side view of the fastener 102 is shown. The tip segment 114 defines a tip segment length TL. The tip segment length TL extends in a direction parallel to the longitudinal axis L of the fastener 102. The shank segment 112 defines a shank segment length SL. The shank segment length SL extends in a direction parallel to the longitudinal axis L of the fastener 102. The shank segment length SL extends from the bottom side 115 of the head 104 of the fastener 102 to the tip segment 114. The ratio of the shank segment length SL to the tip segment length TL is at least 2.5. In some embodiments, the ratio of the shank segment length SL to the tip segment length TL can be at least 3. In some embodiments, the ratio of the shank segment length SL to the tip segment length TL can be at least 3.5. In some embodiments, the ratio of the shank segment length SL to the tip segment length TL can be at least 2. The ratio of the shank segment length SL to the tip segment length TL may be determined by, for example, the desired connection strength provided by the fastener 102 and / or the overall thickness of the workpiece into which the fastener 102 is to be inserted. A larger ratio of the shank segment length SL to the tip segment length TL increases the connection strength because more threads are provided to secure to the workpiece 17. The ratios of the shank segment length to the tip segment length disclosed herein may apply to all embodiments of the fasteners disclosed in this document.

[0255] Reference again Figure 7a , each of the plurality of facets 142 extends from the tip 119 toward the shank segment 112. Specifically, each of the plurality of facets 142 extends from the tip 119 to the shank segment 112. However, in some embodiments, each of the plurality of facets 142 may not extend all the way to the shank segment 112, but may extend from the tip 119 toward the shank segment 112. In this case, the surface segment is arranged between the plurality of facets 142 and the shank segment 112. Whether the plurality of facets 142 extend all the way to the shank segment 112 may be determined by the material from which the workpiece is made. The extension of the plurality of facets 142 to the shank segment 112 provides more heat to the workpiece than the case where the plurality of facets 142 do not extend all the way to the shank segment 112. The tip angle α of the fastener 102 varies around the longitudinal axis L of the fastener. The tip angle α of the fastener 102 is determined by the minimum angle between two diametrically opposed points of the tip segment 112.

[0256] As described above, the method of inserting the fastener 2 as described above is applicable to each of the fasteners disclosed in this document. During use, the plurality of facets advantageously reduces the likelihood of insufficient heating of the workpiece when the fastener 102 is inserted into the workpiece. The faceting of the plurality of facets 142 increases the amount of friction between the tip segment 114 and the workpiece (compared to a rotationally symmetrical tip segment). The increase in friction increases the heat generated between the tip segment and the workpiece, thereby reducing the likelihood of insufficient heating of the workpiece when the fastener 102 is inserted. Because the likelihood of insufficient heating of the workpiece occurring when the fastener 102 is inserted is reduced, the quality of the joint produced using the fastener 102 is improved (compared to a joint produced using a fastener that does not have a plurality of facets).

[0257] In some embodiments, the plurality of surface irregularities may be in the form of a plurality of ribs. Fig.28 Such an embodiment is shown. A plurality of ribs 2142 provide the same advantages as the plurality of facets 142. The plurality of ribs 2142 include four ribs. However, in some embodiments, the plurality of ribs 2142 may include at least two ribs and / or at most six ribs. The length component of each rib in the plurality of ribs 2142 extends in a radial direction (i.e., perpendicular to the longitudinal axis L of the fastener 2102). The ribs 2142 extend from the tip 2119 of the tip segment 2114. The length component of each rib in the plurality of ribs 2142 extends in a circumferential direction (i.e., around the longitudinal axis L of the fastener 2102). The thickness and / or width of the ribs 2142 may be uniform or non-uniform. The thickness of the ribs 2142 may be understood to refer to the distance they protrude from the surface of the tip segment 2114. The thickness and / or width of the ribs 2142 may be minimum at or near the tip 2119 of the tip segment 2114. The thickness and / or width of the rib 2142 can be greatest at or near the tip 2119 of the tip segment 2114. In some embodiments, the plurality of surface irregularities can include two or more facets and one or more ribs.

[0258] In some embodiments, the fastener may include a fixing point. In some embodiments, the fixing point is in the form of a stud. Preferably, where the fastener includes a stud, the fastener insertion device does not include a mold. This is because, where the fastener includes a stud, the mold is generally not accessible to the point of the workpiece where the fastener is inserted. However, where the fastener includes a stud, the fastener insertion device may include a mold. Figure 8An embodiment of a fastener 202 including a fixing point is shown. Similar reference numerals used for fastener 2, fastener 102 are used for fastener 202. Fastener 202 differs from fastener 2, fastener 102 in that fastener 202 also includes a stud 246. However, the tip angle of fastener 202 can correspond to the tip angle of fastener 2. Similarly, tip segment 214 can include multiple facets.

[0259] The stud 246 extends from the top side 244 of the head 204 of the fastener 202. The top side 244 is opposite to the bottom side 215 of the head 204. The stud 246 is threaded. The stud 246 is generally cylindrical. The stud 246 extends along the longitudinal axis L of the fastener 202. The stud 246 allows a component such as an electrical contact to be fixed to the fastener 202. The stud 246 defines a diameter. The diameter of the stud 246 does not need to be the same as the diameter of the shank section 212. The diameter of the stud 246 can be at least 2 mm. The diameter of the stud 246 can be less than or equal to 10 mm. The diameter of the stud 246 can be at least 3 mm. The diameter of the stud 246 can be less than or equal to 8 mm. The diameter of the stud 246 can be less than or equal to 10 mm. The diameter of the stud 246 can be at least 3 mm. The diameter of the stud 246 can be less than or equal to 8 mm. The diameter of the stud 246 does not need to be an integer. For example, the diameter of the stud 246 can be 4.5 mm.

[0260] In some embodiments, the securing point may be in the form of a loop extending from the top side 244 of the fastener 202, for example.

[0261] Fig. 9 The fastener 202 is shown inserted into the workpiece 217, thereby forming a joint 238. In the illustrated embodiment, the workpiece 217 includes a first workpiece layer 218. The first workpiece layer 218 is the only workpiece layer of the workpiece 217. However, in other embodiments, the workpiece 217 may include multiple workpiece layers. Since the first workpiece layer 218 is the only workpiece layer, the first workpiece layer 218 includes a first surface 234 of the workpiece and a second surface 236 of the workpiece.

[0262] In some embodiments, the fastener may include a drilled hole. Fig.10 This embodiment of a fastener 302 is shown. Similar reference numbers used for fastener 2, fastener 102, fastener 202 are used for fastener 302. Although not shown, fastener 302 may also include a stud extending from a top side 344 of head 304 of fastener 302.

[0263] Fastener 302 includes a bore 348. Bore 348 extends into a tip section 314 of fastener 302. Bore 348 extends in a direction parallel to a longitudinal axis L of fastener 302. Shank 310 defines a shank length ZL. Bore 348 defines a bore depth BD. The ratio of bore depth BD to shank length ZL may be at least 0.25. In other words, bore 348 extends along at least 25% of shank length ZL. Tip section 314 includes a ring leading edge 350. Shank length ZL extends from bottom side 315 of head 304 to ring leading edge 350. Ring leading edge 350 may define a ring surface. In the illustrated embodiment, ring leading edge 350 is flat. However, in some embodiments, ring leading edge 350 may be uneven. In such embodiments, ring leading edge 350 may be serrated. Serrated ring leading edge 350 reduces the possibility of insufficient heating of the workpiece during fastener insertion. The borehole defines a borehole surface 355. In some embodiments, the borehole surface 355 may define a plurality of surface irregularities. The surface irregularities may be in the form of, for example, tabs, ribs, and / or protrusions. Where the borehole surface 355 defines a plurality of surface irregularities, the surface irregularities interlock with the workpiece into which the fastener 302 has been inserted, thereby increasing the strength of the connection between the fastener 302 and the workpiece.

[0264] The tip angle α of the tip segment 314 is at least 50°. Because the fastener 302 includes the borehole 348, and therefore the tip segment 314 defines the annular leading edge 350, for a constant tip angle, the initial contact area between the fasteners 302 is greater than if the borehole 348 is not present. This allows the tip angle α of the tip segment 314 of the fastener 302 to be reduced relative to if the borehole is not present, because the increase in contact area increases the heat provided to the workpiece during use. Thus, when a borehole is present, the fastener may, for example, work well at a tip angle of at least 50°, and when a borehole is not present, the fastener may, for example, work well at a tip angle of at least 70°.

[0265] The bore 348 defines a bore inner diameter d. The ratio of the shank diameter to the bore inner diameter d can be at least 1.5. This advantageously provides sufficient material in the shank section 312 so that the fastener 302 can withstand the forces required during use. In some embodiments, the ratio of the shank diameter to the bore inner diameter d can be at least two.

[0266] The ring leading edge 350 merges into the borehole inner diameter d through the tapered surface segment 352. The tapered surface segment 352 includes a chamfered surface segment 354. The angle between the diametrically opposed points of the chamfered surface segment 354 is at least 25 degrees. The angle between the diametrically opposed points of the chamfered surface segment 354 is less than or equal to 45 degrees. The chamfered surface segment 354 abuts the ring leading edge 350. The tapered surface segment 352 includes a rounded surface segment 356. The rounded surface segment 356 abuts the chamfered surface segment 354. The rounded surface segment 356 abuts the borehole inner diameter d. In some embodiments, the tapered surface segment 352 may include only one of the chamfered surface segment 354 and the rounded surface segment 356. In some embodiments, the chamfered surface segment 354 may abut the borehole inner diameter d, and the rounded surface segment 356 may abut the ring leading edge 350. In some embodiments, the entire bore 348 may be cylindrical.

[0267] During fastener insertion, a volume of workpiece material is displaced by the fastener 304. The presence of the borehole 348 advantageously reduces the amount of workpiece material displaced during fastener insertion. This is because a volume of workpiece material is received by the borehole, thereby reducing the amount of workpiece material displaced by the fastener 302. Since the borehole 348 extends along at least 25% of the length of the shank, the amount of material displaced by the fastener 302 during fastener insertion is sufficient to reduce the likelihood of workpiece layer separation. The tapered surface section 352 advantageously promotes deformation of the workpiece material into the borehole 348. The geometry of the annular leading edge 350 incorporated into the borehole inner diameter advantageously more evenly distributes the stresses experienced by the fastener 302 (particularly the shank 310) during fastener insertion.

[0268] The borehole 348 defines a borehole depth. The borehole depth extends from the ring front edge 350 toward the head 304 in a direction parallel to the longitudinal axis L of the fastener 302. The tapered surface segment 352 defines a tapered surface segment depth. The tapered surface segment depth extends from the ring front edge 350 toward the head 304 of the fastener 302 in a direction parallel to the longitudinal axis L of the fastener 302. The ratio of the tapered surface segment depth to the borehole depth is at least 0.1. In some embodiments, the ratio of the tapered surface segment depth to the borehole depth is preferably at least 0.2. The ratio of the tapered surface segment depth to the borehole depth of at least 0.2 provides a gradual transition between the ring front edge 350 and the borehole inner diameter d. This makes the stress distribution in the tip segment 314 more uniform during the fastener insertion process, thereby reducing the possibility of defects when the fastener 302 is inserted into the workpiece. In some embodiments, the ratio of the tapered surface segment depth to the borehole depth can be at least 0.5.

[0269] In some embodiments, the fastener may not be removable from a workpiece into which it is inserted. Fig.11This embodiment of a fastener 402 is shown. Similar reference numerals used for fastener 2, fastener 102, fastener 202, fastener 302 are used for fastener 402. According to previous embodiments herein, fastener 402 may include a bore, a stud, multiple facets, and / or a tip angle.

[0270] The shank segment 412 includes a first threaded portion 458. The first threaded portion 458 abuts the tip segment 414. The shank segment 412 includes a second threaded portion 460. The shank segment 412 includes a flat portion 462. The flat portion 462 may be referred to as a horizontal thread gap. The flat portion 462 is disposed between the first threaded portion 458 and the second threaded portion 460. Fig.11 The fastener 402 is shown inserted into the workpiece 417, thereby forming the joint 438. The flat portion 462 separates the first threaded portion 458 and the second threaded portion 460 from each other. Therefore, the fastener 402 cannot be removed from the workpiece 417 by rotating the fastener 402 in the opposite direction of the threads of the shank section 412. This is because the material of the workpiece 417 interferes with the second threaded portion 460, thereby preventing the fastener from rotating. During the fastener insertion process, the material of the workpiece 417 softens due to the heat provided. The softened material of the workpiece 417 allows the material of the workpiece to deform around the first threaded portion 458 and the second threaded portion 460. In some embodiments, the pitch, thread angle and / or diameter of the first threaded portion 458 can be greater than or equal to the pitch, thread angle and / or diameter of the second threaded portion 460. In some embodiments, the pitch and / or diameter of the first threaded portion 458 can be less than or equal to the pitch and / or diameter of the second threaded portion 460.

[0271] In some embodiments, at least a portion of the shank section of the fastener shank is unthreaded. Fig.12 An embodiment of such a fastener 502 is shown, which is inserted into a workpiece 517, thereby forming a joint 538. Similar reference numerals used for fastener 2, fastener 102, fastener 202, fastener 302, fastener 402 are used for fastener 502. In this embodiment, the drive geometry 506 of the head 504 of the fastener 502 is an internal drive geometry. However, the drive geometry 506 can be an external drive geometry, or other drive geometry. The fastener 502 can include any of the disclosed features associated with the previous embodiments of this document.

[0272] The shank section 512 includes a first shank portion 570. The shank section 512 includes a second shank portion 572. The first shank portion 570 abuts the head of the fastener 502. The first shank portion 570 includes a base section 511 of the shank section 512. The second shank portion 572 abuts the first shank portion 570 and the tip section 514. The first shank portion 570 is unthreaded. The second shank portion 572 is threaded. Because only a portion of the shank section 510 is threaded, the force required to insert the fastener 502 into the workpiece is reduced relative to the case where the entire shank section is threaded. This is because the resistance to fastener insertion is reduced relative to the case where the entire shank section 510 is threaded (this is because the surface area in contact with the workpiece is reduced).

[0273] In some embodiments, a fastener may include one or more retaining features that engage a workpiece into which the fastener is inserted during use. Fig.13 602 is depicted. Similar reference numerals used for the previous embodiments of the fasteners described herein are used for the fastener 602. The first shank portion 670 of the fastener 602 is unthreaded. The second shank portion 672 is threaded. The first shank portion 670 includes a plurality of protrusions 674 ( Fig.13 Only one of them is marked in the figure). A plurality of protrusions 674 are arranged in an array. A plurality of cavities 675 are alternately arranged between the plurality of protrusions 674. The plurality of protrusions 674 include six protrusions. However, in other embodiments, the plurality of protrusions may include any suitable number of protrusions. The plurality of protrusions 674 do not extend radially beyond the threads of the second shank portion 672. In some embodiments, the plurality of protrusions 674 may protrude radially beyond the threads of the second shank portion 674. In the illustrated embodiment, the protrusions in the plurality of protrusions 674 extend parallel to the longitudinal axis L of the fastener 602. In other embodiments, the protrusions in the plurality of protrusions may be twisted around the longitudinal axis L of the fastener 602. When the plurality of protrusions are twisted around the longitudinal axis L of the fastener 602, the protrusions in the plurality of protrusions 674 extend around the longitudinal axis L of the fastener 602 and extend in a direction parallel to the longitudinal axis L of the fastener.

[0274] When inserted into the workpiece ( Fig.13), the material of the workpiece deforms around the plurality of protrusions 674 and enters the cavities of the plurality of cavities 675. The material of the workpiece at least partially fills the cavities in the plurality of cavities 675. Therefore, during use, the plurality of protrusions 674 engage with the workpiece into which the fastener is inserted. Through the interaction between the plurality of protrusions 674 and the workpiece material, the fastener 602 can be prevented from rotating after insertion. Therefore, the plurality of protrusions 674 can be referred to as retaining features. In some embodiments, only one protrusion needs to be provided. Therefore, the fastener 602 includes one or more retaining features. In some embodiments, the one or more retaining features can be in the form of ribs extending, for example, around the longitudinal axis L of the fastener 602 or in a direction parallel to the longitudinal axis L of the fastener 602.

[0275] In some embodiments, the tip section of the fastener may define an undercut. Fig.14 Similar reference numerals are used for fastener 702 as used for previous fasteners disclosed herein. Fig.14 Fastener 702 is shown inserted into workpiece 717, thereby creating joint 738. The maximum diameter of tip segment 714 of shank 710 is greater than the diameter of shank segment 712 of shank 710. Therefore, tip segment 714 defines undercut 776. Undercut 776 is disposed adjacent to shank segment 712. Due to the presence of undercut 776, the amount of interference between fastener 702 and workpiece 717 is increased relative to a situation where undercut 776 is not provided. The increase in interference between fastener 702 and workpiece 717 increases the strength of the connection between fastener 702 and workpiece 717.

[0276] In some embodiments, the fastener may include a washer. Fig.15 802. The fastener 802 may include any of the features described with reference to the previous embodiments. The fastener 802 includes a washer 878. The washer 878 engages with the bottom side 815 of the head 804 of the fastener 802. The provision of the washer 878 reduces the possibility of the fastener rotating during use (i.e., after the joint is formed). Rotation of the fastener 802 during use is undesirable because the rotation may cause the fastener to loosen. Therefore, the provision of the washer 878 provides a stronger joint. The washer 878 may be configured to seal against the head 804 of the fastener 802 and seal against the workpiece during use ( Fig.15802 is formed of steel and the workpiece is formed of magnesium. The washer 878 formed of aluminum may be particularly advantageous. The washer 878 formed of aluminum prevents the formation of a galvanic corrosion cell.

[0277] In some embodiments, the diameter of the shank of the fastener need not be uniform along the length of the shank. Fig.16 Such a fastener is shown as 902. Similar reference numerals are used for fastener 902 as for the fasteners of the previous embodiments. Fig.16 The fastener 902 is shown inserted into the workpiece 917, thereby producing a joint 938. The fastener 902 may include any of the features described with reference to the previous embodiments. In this embodiment, the diameter of the first shank portion 970 is greater than the diameter of the second shank portion 972. In other embodiments, the diameter of the second shank portion 972 may be greater than the diameter of the first shank portion 970. The geometry of the shank segment 912 of this embodiment displaces less material of the workpiece 917 than a fastener having a shank of constant diameter. In addition, the axial load applied to the fastener 902 during the fastener insertion process may be reduced compared to a fastener having a shank of constant diameter. This advantageously reduces the likelihood of cracking of the workpiece 917 due to the fastener insertion process. Since the likelihood of cracking of the workpiece 917 is reduced, the fastener 917 may advantageously produce a stronger joint. In addition, since less material is displaced by the fastener 917, the resistance to deformation of the workpiece 917 is reduced compared to a fastener having a shank of constant diameter. Thus, with an axial load applied to fastener 902 equal to an axial load applied to a fastener having a shank of constant diameter, the time required to insert the fastener into workpiece 917 is reduced. This therefore makes the fastener insertion process more efficient.

[0278] In some embodiments of the method of inserting a fastener, the method may include providing an opening in the first workpiece layer. This may be particularly advantageous in the case where the workpiece includes layers of different materials, particularly in the case where one or more workpiece layers provided with the one or more openings are not easily formable. In the case where the workpiece includes one or more intermediate layers, the method may further include providing an opening in at least one or more intermediate layers. The method may include providing an opening in all intermediate layers. The opening provided in the first workpiece layer may be referred to as a pre-hole. Fig.17A joint 1038 produced by this method is depicted. It can be seen that the first workpiece layer 1018 includes an opening 1090. The opening 1090 can be provided using any known method (e.g., machining). In this embodiment, the second workpiece layer 1020 includes the first surface 1034 of the workpiece 1017. The material from which the first workpiece layer 1018 is made can be, for example, a composite material. The material from which the first workpiece layer 1018 is made can be any other low ductility material.

[0279] The shape of at least a portion of the opening may correspond to the shape of the fastener. Fig.29 An embodiment is shown in which the shape of opening 1990 corresponds to the shape of head 1904 of fastener 1902 . Fig.30 Also shown is an embodiment in which the shape of the opening 2090 corresponds to the shape of the head 2004 of the fastener 2002. Fig.29 and Fig.30 , the shapes of a portion of openings 1990, 2090 correspond to the shapes of heads 1904, bottom sides 1915, 2015 of respective fasteners 1902, 2002. The openings may be sized relative to the fasteners to be inserted into workpieces 1917, 2017. The size of openings 1990, 2090 relative to fasteners 1902, 2002 may be selected based on, for example, the material from which workpieces 1917, 2017 are made. For example, larger openings may be used for harder and / or stronger workpieces. Fig.29 In FIG. 1 , the size of opening 1990 corresponds to the size of the portion of fastener 1902 that will be received in first workpiece layer 1918. That is, the ratio of the size of opening 1990 to the size of the portion of fastener 1902 that will be received in first workpiece layer 1918 is 1:1. Fig.30 , the size of opening 2090 is 25% of the size of the portion of fastener 2002 to be received in first workpiece layer 2018. That is, the ratio of the size of opening 2090 to the size of the portion of fastener 2002 to be received in first workpiece layer 2018 is 1:4. In general, the ratio of the size of the opening to the size of the portion of the fastener to be received in the first workpiece layer can be at least 1:4 and / or at most 1:1, and / or at most 2:1.

[0280] In some embodiments, where the method includes providing an opening in the first workpiece layer 1018, the method may further include centering the fastener 1002 relative to the opening 1090. Centering the fastener 1002 relative to the opening 1090 may be performed using a machine vision system. The machine vision system may constitute a fastener insertion device ( Fig.17The machine vision system is configured to identify the opening 1090 and determine the center of the opening. This information is then provided to the fastener insertion device. The fastener insertion device then adjusts the position of the fastener 1002 so that the fastener is centered relative to the opening 1090. After the fastener 1002 is centered relative to the opening 1090, the longitudinal axis L of the fastener is aligned with the central axis ( Fig.17 The central axis of the opening 1090 is an axis extending along the center of the opening.

[0281] Centering the fastener 1002 relative to the opening 1090 advantageously reduces the likelihood that the fastener will contact the surface of the opening during fastener insertion. Contact between the fastener 1002 and the surface of the opening is undesirable because it may result in improper fastener insertion. Centering the fastener 1002 provides a consistently formed joint.

[0282] The method of inserting the fastener into the workpiece 1017 is otherwise the same as described above. Providing the opening 1090 allows the fastener to be used to connect the first workpiece layer 1018 to the second workpiece layer 1020, where the first workpiece layer 1018 is made of a material that is not easily formed.

[0283] In some embodiments, the drive geometry of the fastener may be an internal drive geometry. Fig.18 Fastener 1102 is depicted wherein drive geometry 1106 is an internal drive geometry. This allows fastener 1102 to be inserted into a workpiece ( Fig.18 The internal drive geometry 1106 may be hexagonal or may have some other suitable shape (this also applies to the external drive geometry). Because the drive geometry 1106 is an internal drive geometry, the diameter of the head 1104 of the drive geometry 1106 is reduced compared to a fastener having an external drive geometry. The drive geometry 1106 allows the fastener 1102 to be used in narrower workpieces ( Fig.18 1104, and the head 1104 does not overhang the workpiece. This drive geometry and other internal drive geometries can be used in combination with other fastener embodiments.

[0284] In some embodiments, a fastener may include one or more retaining features. Fig.19 Another embodiment of a fastener 1202 including one or more retention features is shown. In this embodiment, the one or more retention features are a plurality of recesses 1292 (in Fig.19Only one of them is marked in the figure). In some embodiments, only at least one recess needs to be provided. In the illustrated embodiment, the plurality of recesses 1292 includes four recesses. In other embodiments, the plurality of recesses 1292 may include any suitable number of recesses. For example, the plurality of recesses 1292 may include at least two recesses. In some embodiments, the plurality of recesses 1292 may include equal to or less than 4 recesses. In some embodiments, the plurality of recesses 1292 may include equal to or less than 6 recesses. The recess 1292 extends into the shank section 1212 of the fastener 1202. The recess 1292 extends toward the longitudinal axis L of the fastener 1202. The plurality of recesses 1292 extends in a direction parallel to the longitudinal axis L of the fastener 1202. In some embodiments, the plurality of recesses 1292 may extend at least partially around the longitudinal axis L of the fastener 1202.

[0285] The plurality of recesses 1292 extend along the entire length of the shank segment 1212. In some embodiments, the plurality of recesses may extend partially along the shank segment 1212. In some embodiments, the plurality of recesses 1292 may extend only along the first shank portion 1270. In some embodiments, the plurality of recesses 1292 may extend only along the second shank portion 1272. The plurality of recesses 1292 may be referred to as vertical thread gaps. Due to the presence of the plurality of recesses 1292, the fastener 1202 cannot be removed from the workpiece into which the fastener is inserted. This is because the plurality of recesses interfere with the workpiece material.

[0286] In some embodiments, the fastener may include one or more auxiliary fixing features. The one or more auxiliary fixing features may be in the form of one or more surface irregularities. Fig. 20 An embodiment of a fastener 1302 including one or more auxiliary fixing features is shown. In the illustrated embodiment, the one or more auxiliary fixing features are in the form of threads 1394 disposed on the bottom side 1315 of the head 1304 of the fastener 1302. The direction of the threads 1394 is the same as the direction of the threads of the shank section 1312. In some embodiments, the direction of the threads 1394 can be opposite to the direction of the threads of the shank section 1312. In other embodiments, the one or more retaining features can be in the form of any other type of surface irregularity, such as protrusions and / or ribs. When the workpiece ( Fig. 20 When the fastener 1302 is secured to the workpiece (not shown), the threads 1394 engage the workpiece, thereby further securing the fastener 1302 to the workpiece. One or more secondary securing features advantageously reduce the likelihood of the fastener 1302 becoming loose when subjected to vibration loads. Therefore, one or more secondary securing features advantageously create a stronger joint.

[0287] In some embodiments, where a mold is provided during the fastener insertion process, the mold can be a ring mold. Fig.21 This embodiment is shown in FIG. Fig.21 In the embodiment, fastener 702 is fixed to workpiece 1417. However, any fastener described in this document can be used in combination with the ring die. Fig.21 The joint 1438 is shown in combination with a ring die 1495. The ring die 1495 includes a cavity 1496. The ring die 1495 includes a protrusion 1497. The protrusion 1497 is annular and is arranged as a lip around the cavity 1496. During the fastener insertion process, the protrusion 1497 pushes the material of the workpiece 1417 into the threads of the fastener 702. In addition, where the fastener includes an undercut 776, the protrusion 1497 pushes the material of the workpiece 1417 into the undercut 776 of the fastener 702. Advantageously, this improves the engagement between the fastener 702 and the material of the workpiece 1417. The improved engagement between the fastener 702 and the material of the workpiece 1417 advantageously increases the strength of the connection between the fastener 702 and the workpiece 1417.

[0288] As described above, in some embodiments, the tip section of the handle can be rounded. Fig. 22 1502. This embodiment is shown. It can be seen that the tip segment 1514 is rounded. The tip 1519 of the tip segment 1514 is pointed. In some embodiments, the tip 1519 of the tip segment 1514 can be rounded. The tip segment 1514 defines a tip angle α. The tip angle α is the angle between the first tangent line T1 and the second tangent line T2. The first tangent line T1 and the second tangent line T2 extend through diametrically opposed points of the tip segment 1514. The point through which the first tangent line T1 extends and the point through which the second tangent line T2 extends are located at the same position along the longitudinal axis L of the fastener 1502. The points through which the first tangent line T1 and the second tangent line T2 extend are located so that the angle between the first tangent line T1 and the second tangent line T2 is at a maximum.

[0289] As mentioned above, the fastener may be provided with a completely cylindrical bore. Fig.23 This embodiment is shown. It can be seen that the entire bore 1648 of the fastener 1602 is cylindrical. The tip angle α of the tip segment 1614 is the angle between diametrically opposed points of the tip segment 1614. Fig.23 The tip angle α in φ is measured between a first tangent line T1 and a second tangent line T2. The first tangent line T1 and the second tangent line T2 extend through diametrically opposed points of the tip segment 1614.

[0290] Fig.31Another embodiment of a fastener 1802 is shown. Fastener 1802 includes a bore 1848. Bore 1848 is conical. In other embodiments not shown, bore 1848 may be truncated cone, cylindrical, or any other suitable shape. The ratio of bore depth BD to shank length ZL may be at most 0.25. That is, bore depth BD may be at most 25% of shank length ZL. In some embodiments, bore depth may be at most 10% of shank length ZL. Drill depth BD may be selected based on, for example, the hardness of the workpiece into which fastener 1802 is to be inserted, the strength of the workpiece, and / or the thickness of the workpiece. A shallower ratio of bore depth BD to shank length ZL may be particularly suitable for harder, stronger, and / or thinner workpieces. The arrangement of the bore forms an annular initial contact area between fastener 1802 and the workpiece. The annular initial contact area increases the speed at which a portion of fastener 1802 contacts the workpiece compared to a point contact area. This increase in speed increases the amount of heat provided by the fastener 1802 to the workpiece, thereby reducing the time required to heat the workpiece.

[0291] In some embodiments, the fastener can remove excess or extruded workpiece material. When the fastener is inserted into the workpiece, the workpiece material can be extruded from the workpiece in a direction opposite to the direction of insertion of the fastener. When extruded, the material of the workpiece is in a softened state, but not liquid. This excess material is undesirable because it is easily corroded, which can cause joint failure. Fig.32 2202 is a fastener 2202 having a plurality of cutting edges 2297 (in the embodiment of the present invention). Fig.32 Only one of them is marked in the figure). Generally, the cutting edges do not need to be sharp because the extruded material is softened when it is cut by the cutting edge of the fastener. The cutting edges 2297 each form a corresponding tooth 2298 ( Fig.32 The teeth 2298 extend from a circumferential periphery 2299 of the head 2204. The plurality of teeth 2298 includes four teeth 2298, and thus four cutting edges 2297 are provided. However, in some embodiments, the head 2204 may include at least one tooth, and / or at most six teeth, each tooth being provided with a corresponding cutting edge. Fig.33An alternative embodiment of a fastener 2302 is shown that includes a plurality of cutting edges 2397. The cutting edges 2397 each form a portion of a corresponding rib in a plurality of ribs 2398. The ribs 2398 are disposed on the bottom side 2315 of the head 2304. The plurality of ribs 2398 include five ribs, and therefore five cutting edges 2397 are disposed. However, in some embodiments, the head 2304 may include at least one rib, and / or up to six ribs, each rib being provided with a corresponding cutting edge. The number of teeth 2298 or ribs 2398, and therefore the number of cutting edges 2297, 2397, may be selected based on, for example, the hardness of the material of the workpiece into which the fastener 2202 is to be inserted.

[0292] In the presence of cutting edges 2297, 2397 (which may be the case with any of the embodiments disclosed herein), the method of inserting a fastener into a workpiece may also include cutting extruded or excess material from the workpiece using the cutting edge. The cutting of excess workpiece material may be performed after the fastener is screwed into the workpiece. However, the threads do not need to be fully formed before starting to cut excess workpiece material.

[0293] exist Fig.33 In the embodiment, the ribs in the plurality of ribs 2398 are provided with rounded corners. The ribs in the plurality of ribs are generally circular. Since the extruded material is softened, the ribs 2398 can cut the extruded material from the workpiece during the fastener insertion process. In some embodiments not shown, each of the plurality of ribs 2398 can define a corresponding vertex. In the case of providing a vertex, the vertex defines the cutting edge of each rib.

[0294] In some embodiments, a nose piece of an insertion device for inserting any of the above-described fasteners is capable of removing excess workpiece material. Fig.34 24 shows an embodiment of such a front end member 2426. The front end portion includes a plurality of cutting edges 2497 (in Fig.34 The plurality of cutting edges 2497 include two cutting edges. The two cutting edges are diametrically opposed to each other. In some embodiments, the front end 2426 may include at least one, and / or at most four, cutting edges.

[0295] Although a number of specific embodiments of the present invention have been described above, features of the various embodiments may be combined. For example, a fastener may include a bore (such as fastener 302) and a stud (such as fastener 202). Fig.35An embodiment of a fastener 1702 is shown that combines features of the above embodiments. The fastener 1702 includes a first threaded portion 1658 and a second threaded portion 1760. The fastener 1702 also includes a retaining feature in the form of a plurality of protrusions 1774. The plurality of protrusions are arranged between the first threaded portion 1558 and the second threaded portion 1760. The pitch of the threads of the first threaded portion 1758 is less than the pitch of the threads of the second threaded portion 1760.

[0296] Although specific embodiments of the present invention have been described above, it should be understood that the present invention may be practiced in a manner other than that described. The above description is intended to be illustrative rather than limiting. Therefore, it will be apparent to those skilled in the art that modifications may be made to the described invention without departing from the scope of the claims set forth below.

Claims

1. A hole forming and thread forming fastener comprising: a head and a handle defining a longitudinal axis, the handle comprising a handle segment and a tip segment, wherein the handle segment extends from the head and the tip segment extends from the handle segment and is opposite the head; wherein at least a portion of the shank section is threaded; and Therein, the tip section is at least partially conical and defines a tip angle, the tip angle being at least 50 degrees.

2. The hole forming and thread forming fastener according to claim 1, wherein: The tip angle is at least 70 degrees.

3. The hole forming and thread forming fastener according to claim 1 or 2, wherein: The tip segment defines a tip segment length, and the shank segment defines a shank segment diameter, and wherein a ratio of the tip segment length to the shank segment diameter is less than or equal to 0.

6.

4. A hole forming and thread forming fastener according to any one of the preceding claims, wherein: The tip angle is less than or equal to 160 degrees.

5. A hole forming and thread forming fastener according to any one of the preceding claims, wherein: The tip angle is at least 125 degrees and less than or equal to 135 degrees.

6. A hole forming and thread forming fastener according to any one of the preceding claims, wherein: The handle section includes a first handle portion adjacent to the head section and a second handle portion adjacent to the tip section.

7. The hole forming and thread forming fastener of claim 6, wherein: The first shank portion is unthreaded and the second shank portion is threaded.

8. A hole forming and thread forming fastener according to claim 6 or 7, wherein: The first shank portion includes one or more retaining features, and wherein the one or more retaining features engage with a workpiece into which the hole forming and thread forming fastener is inserted during use.

9. A hole forming and thread forming fastener according to any one of claims 6 to 8, wherein: The first handle portion has a diameter greater than a diameter of the second handle portion.

10. A hole forming and thread forming fastener according to any one of the preceding claims, wherein: The head defines an undercut.

11. A hole forming and thread forming fastener according to any one of the preceding claims, further comprising a threaded stud extending from a side of the head opposite to the bottom side.

12. A hole forming and thread forming fastener according to any one of the preceding claims, wherein: The tip segment defines an undercut disposed adjacent the shank segment.

13. A hole forming and thread forming fastener according to any one of the preceding claims, wherein: The pitch diameter of the threads of the shank segment is constant along at least 90% of the length of the shank segment.

14. A method of inserting a fastener into a workpiece, the method comprising: Providing a fastener, the fastener being the fastener according to any one of claims 1 to 13; Providing a workpiece, the workpiece comprising a first surface and a second surface, the second surface being opposite to the first surface; rotating the fastener about a longitudinal axis of the fastener and bringing the fastener into contact with the first surface of the workpiece to heat the workpiece; screwing the fastener into the workpiece by moving the fastener and the workpiece relative to each other in a direction parallel to the longitudinal axis of the fastener such that the tip section of the fastener penetrates the first surface; Wherein, the fastener does not penetrate the second surface of the workpiece.

15. The method according to claim 14, wherein: Threading the fastener into the workpiece includes forming threads in the workpiece with the fastener.

16. A method according to claim 14 or 15, further comprising providing a die, and wherein the second surface engages the die when the fastener is screwed into the workpiece.

17. The method according to claim 16, wherein: The die includes a die recess, and wherein the second surface of the workpiece deforms into the die recess when the fastener is screwed into the workpiece.

18. The method according to claim 17, wherein: The die recess defines a die recess volume, and wherein a volume of workpiece material is displaced when the fastener is threaded into the workpiece, and wherein the die volume is equal to or greater than the volume of the workpiece material displaced.

19. The method according to any one of claims 14 to 18, wherein: The workpiece comprises only a single workpiece layer.

20. The method according to any one of claims 14 to 18, wherein: The workpiece includes a first layer and a second layer.

21. The method according to claim 20, wherein: At least one layer of the workpiece is made of a metallic material, optionally wherein at least one layer of the workpiece is made of aluminum.

22. The method according to claim 20 or 21, wherein: The first workpiece layer includes an opening through which the fastener passes prior to contacting the workpiece.

23. The method according to claim 22, wherein: The first workpiece layer is formed from a composite material.

24. The method according to any one of claims 14 to 23, wherein: The fastener also includes a threaded stud extending from a side of the head opposite the shank section of the shank, and wherein the method further includes securing a component to the threaded stud.

25. The method according to claims 14 to 24, wherein: The rate at which the fastener rotates relative to the workpiece is reduced at least once as the fastener is threaded into the workpiece.

26. A method according to claim 25 when appended to claim 20, wherein: When the tip segment is located in the second workpiece layer, the rate at which the fastener rotates relative to the workpiece is reduced.

27. The method according to any one of claims 14 to 26, wherein: After the fastener is screwed into the workpiece, the second surface of the workpiece includes a protrusion in which at least a portion of the tip section of the shank of the fastener is received.

28. A connector, comprising: a workpiece, the workpiece comprising a first surface and a second surface; The fastener of any one of claims 1 to 13, wherein the fastener extends through the first surface and does not penetrate the second surface.

29. The connector of claim 28, wherein The workpiece includes a first workpiece layer and a second workpiece layer, the first workpiece layer includes the first surface, and the second workpiece layer includes the second surface.

30. The connector of claim 29, wherein: The first workpiece layer includes an opening through which the thread-forming and hole-forming fasteners extend.

31. A joint according to claim 29 or 30, wherein The first workpiece layer is formed from a composite material.

32. The connector of claim 28, wherein: The workpiece comprises only a single workpiece layer.

33. A joint according to any one of claims 28 to 32, wherein The thread forming and hole forming fastener also includes a threaded stud extending from a side of the head opposite the shank section.

34. A joint according to any one of claims 28 to 33, wherein At least one layer of the workpiece is made of a metallic material, optionally wherein at least one layer of the workpiece is made of aluminum.

35. A joint according to any one of claims 28 to 34, wherein The head of the thread forming and hole forming fastener is arranged to be higher than the workpiece, or wherein the head of the thread forming and hole forming fastener is arranged substantially flush with the workpiece.

36. A joint according to any one of claims 28 to 34, wherein The second surface includes a protrusion in which the tip section of the fastener is at least partially received.

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