Self-Clinching Fasteners

Abstract

A self-clinching fastener for attachment to a plastically deformable metal substrate includes a body portion having a central axis, the body portion having an annular surface extending in a direction perpendicular to the central axis. The annular surface includes a first annular surface, a second annular surface, and a third annular surface. The third annular surface is located on an imaginary horizontal plane. A punch portion extends from the body portion. A plurality of spaced-apart lugs surround the punch portion. The first annular surface extends radially outward from an outer peripheral surface of the punch portion, and the second annular surface is radially disposed between the first and third annular surfaces. One of the plurality of lugs is inclined downward to the second annular surface.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] None

[0002]

[0002] This application relates generally to self-attaching fasteners, and more specifically to clinch nuts. [Background technology]

[0003]

[0003] Self-attaching fasteners are used in many industries, such as the automotive and home appliance industries, to secure various components to metal panels. When a clinch nut is attached to a metal panel, a screw or bolt is threaded into the clinch nut and tightened to a specified torque value. During installation, the clinch nut must have sufficient rotational resistance to prevent the clinch nut from rotating relative to the metal panel when a screw is inserted and tightened. During use, the clinch nut must have sufficient pull-out resistance to prevent the clinch nut from coming loose from the metal panel when subjected to an external force, such as vibration or other tensile force.

[0004]

[0004] Clinch nuts typically include a central pilot or punch portion that extends at least partially through an opening in a metal plate or panel. When the clinch nut is self-piercing, the central pilot portion cooperates with a tool to form an opening in the metal panel when the clinch nut is attached to the metal panel. The clinch nut is attached to the metal panel by a die member that forms a mechanical connection between the clinch nut and the metal panel. Generally, the die member is a reflective die having a shape corresponding to the shape of the clinch nut. More specifically, such reflective die members typically include ridges that facilitate deformation of the metal panel around the opening into an annular groove in the clinch nut that surrounds the pilot portion and / or deform the pilot portion of the clinch nut onto the metal panel to capture the metal panel. In such conventional applications, a force of 12 tons (or more) is required to physically connect the clinch nut to the metal panel. Furthermore, due to the amount of force used and the typical configuration of the reflective die, the reflective die often fails (i.e., breaks, deforms, etc.) after 100 to 1,000 uses. Such elements are particularly prone to failure at the raised portions of the reflective dies as they repeatedly apply sufficient force to separate successive metal panels and secure each clinch nut thereto.

[0005]

[0005] Therefore, there is a need in the art for an improved clinch nut that can be securely and consistently attached to a metal panel, has sufficient push-out strength, sufficient rotational resistance, and extends the life of the tooling (e.g., die members). Further, there is a need for a clinch nut that is relatively inexpensive to manufacture and relatively easy to use. Summary of the Invention

[0006] According to one aspect, a self-clinching fastener for attachment to a plastically deformable metal substrate is provided. The self-clinching fastener includes a body portion having a central axis. The body portion includes an outer circumferential surface extending in the direction of the central axis and an annular surface extending in a direction perpendicular to the central axis. The annular surfaces include a first annular surface, a second annular surface, and a third annular surface. The third annular surface lies on an imaginary horizontal plane, and the first and second annular surfaces define a rim that projects away from the imaginary horizontal plane in the direction of the central axis.

[0007]

[0007] The punch portion is coaxial with the central axis, and an annular surface extends from the body portion to surround the punch portion. The punch portion includes an outer circumferential surface extending in the direction of the central axis. A plurality of spaced-apart lugs surround the punch portion and project axially outward from the annular surface. One of the plurality of lugs is inclined downward in a radially outward direction of the self-clinching fastener with respect to an imaginary horizontal plane. A first annular surface extends radially outward from the outer circumferential surface of the punch portion. A second annular surface is radially disposed between the first annular surface and the third annular surface, and the one of the plurality of lugs is inclined downward to the second annular surface.

[0008] According to another aspect, there is provided a self-clinching fastener for attachment to a plastically deformable metal substrate. The self-clinching fastener includes a body portion having a central axis. The body portion includes an outer circumferential surface extending in the direction of the central axis and an annular surface extending in a direction perpendicular to the central axis. The annular surfaces include a first annular surface, a second annular surface, and a third annular surface. The third annular surface lies on an imaginary horizontal plane, and the first and second annular surfaces define a rim that projects away from the imaginary horizontal plane in the direction of the central axis. The punch portion is coaxial with the central axis, and an annular surface extends from the body portion to surround the punch portion. The punch portion includes an outer circumferential surface extending in the direction of the central axis and has a cylindrical contour lying on an imaginary peripheral plane. A plurality of spaced apart lugs surround the punch portion and protrude axially outward from the annular surface. One of the plurality of lugs is inclined downwardly relative to an imaginary horizontal plane, radially outward of the self-clinching fastener. The first annular surface extends radially outward from the outer peripheral surface of the punch portion, and the second annular surface is radially disposed between the first and third annular surfaces. The first annular surface has a planar cross-section and is angled relative to an imaginary horizontal plane. The second annular surface has a concave cross-section such that the second annular surface continuously curves radially outward toward the imaginary horizontal plane. The one of the plurality of lugs is inclined downward to the second annular surface. [Brief explanation of the drawings]

[0009] [Figure 1]

[0009] An oblique view of a clinch nut. [Figure 2]

[0010] FIG. 2 is a plan view of the clinch nut shown in FIG. [Figure 3]

[0011] FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. [Figure 4]

[0012] FIG. 4 is an enlarged view of the detailed area “4” shown in FIG. [Figure 5]

[0013] FIG. 4 is an enlarged view of the detailed area “5” shown in FIG. 3. [Figure 6]

[0014] FIG. 2 is a perspective view of a stud including a clinch attachment portion shown in FIG. 1. [Figure 7]

[0015] FIG. 10 is a perspective view of an alternative clinch nut. DETAILED DESCRIPTION OF THE INVENTION

[0010]

[0016] Referring to the drawings, FIG. 1 shows a fastener 100 or nut for attachment to a plastically deformable metal plate or panel. Fastener 100 may be a self-clinching fastener that, upon installation, tightens into a pre-drilled hole formed in the metal panel. Preferably, fastener 100 is a self-piercing and self-clinching fastener that, upon installation, pierces an opening in the metal panel and tightens itself into the opening. While the illustrated embodiment is a nut, it should be noted that other self-piercing and self-clinching fasteners, such as a self-piercing and / or self-clinching stud (shown in FIG. 6 and briefly described below), are within the scope of the present invention. For brevity, much of the following description will be in terms of self-clinching nuts and self-piercing nuts, but it will be understood that the present disclosure applies equally to self-piercing and / or self-clinching studs.

[0011]

[0017] Fastener 100 has a body portion 102 and a pilot or punch portion 104 extending from one end of body portion 102. A threaded hole or bore 106 extends axially through both body portion 102 and punch portion 104. Furthermore, body portion 102 and punch portion 104 are coaxial with a central axis "X." When fastener 100 is installed in a plastically deformable metal substrate, a mating threaded fastener (e.g., a bolt, a screw, etc.) may be inserted into threaded hole 106 and attached to threaded hole 106. If the fastener is a self-piercing and self-clinching stud, punch portion 104 is solid and does not have a through-hole; instead, a threaded or unthreaded stud may extend outward from the opposite side of body portion 102 (i.e., from the bottom or first end face 102a of fastener 100). Preferably, such studs are centered about and coaxial with the central axis "X." The studs may be perpendicular to the first end face 102a, or may be disposed at an angle relative to the central axis "X," if desired.

[0012]

[0018] 1-3, body portion 102 extends to a bottom or first end surface 102a of fastener 100, corresponding to one axial end of fastener 100. First end surface 102a of fastener 100 is shown as being substantially perpendicular to central axis "X." However, first end surface 102a may have other geometric configurations; for example, first end surface 102a may be chamfered. Specifically, first end surface 102a may be angled upward or downward relative to central axis "X." In other words, first end surface 102a may have a circumferential surface that gradually converges radially inward or gradually diverges radially outward relative to the installation direction of fastener 100. As further shown, punch portion 104 extends to an upper or second end face 104a of fastener 100, which corresponds to the other axial end of fastener 100. Second end face 104a of fastener 100 is similarly depicted as being substantially perpendicular to central axis "X," although, alternatively, second end face 104a may be chamfered, as described above with respect to first end face 102a.

[0013]

[0019] Punch portion 104 is radially smaller than body portion 102 such that body portion 102 includes a generally annular surface 108 that surrounds punch portion 104. That is, punch portion 104 extends from body portion 102 in the direction of a central axis "X," and annular surface 108 is disposed to surround punch portion 104. Annular surface 108 extends in a direction perpendicular to the central axis (i.e., in the radial direction "r" of fastener 100, as shown in FIG. 2) and is configured to engage a metal panel to which fastener 100 is to be installed.

[0014]

[0020] As further shown, fastener 100 includes a plurality of spaced apart lugs 110 that collectively surround punch portion 104. Each of lugs 110 projects axially outward from annular surface 108 in a direction opposite first end face 102a of fastener 100. In one embodiment, as shown, lugs 110 are equally spaced apart from one another and all have the same configuration. Alternatively, lugs 110 may be unevenly spaced apart from one another around punch portion 104 and / or may have various configurations.

[0015]

[0021] As shown in FIGS. 1 and 3 , the body portion 102 and the punch portion 104 each include an outer periphery 112, 114 extending in the direction of a central axis “X.” In one embodiment, the outer periphery 112 of the body portion 102 is planar and parallel to the central axis “X,” providing a polygonal shape with flat sides that is easily usable in machine tools. Alternatively, the outer periphery 112 of the body portion 102 may be convexly or concavely curved and / or non-parallel to the central axis “X.” In the illustrated example, the outer periphery 112 of the body portion 102 is polygonal and is formed by multiple faces. Specifically, as shown in FIG. 2 , the outer periphery 112 of the body portion 102 is formed by eight faces, all of which have the same dimensions (i.e., height and width). Alternatively, a total of four to twelve faces may form the outer periphery 112 of the body portion 102. It is further noted that the outer circumferential surface 112 of body portion 102 need not be polygonal and may have other geometric configurations (e.g., cylindrical). The height (i.e., axial dimension) and width (i.e., radial dimension) of body portion 102 are selected to provide sufficient threaded engagement between threaded bore 106 and a mating externally threaded member (e.g., a bolt) so that the mating externally threaded member can consistently engage and disengage from threaded bore 106 without stripping the threads. If fastener 100 has a self-clinching stud, the height and width of body portion 102 can likewise be selected to provide sufficient strength for the stud and the intended mating fastener.

[0016]

[0022] 2 and 4, FIG. 4 is an enlarged detailed view of the circled area of ​​fastener 100 shown in FIG. 3, with annular surface 108 lying on an imaginary horizontal plane "P." Specifically, imaginary horizontal plane "P" is configured such that central axis "X" is perpendicular to imaginary horizontal plane "P." Furthermore, annular surface 108 comprises a first annular surface 108a, a second annular surface 108b, and a third annular surface 108c. First annular surface 108a is surrounded by second annular surface 108b (i.e., first annular surface 108a is disposed radially closer to punch portion 104 than second annular surface 108b), and second annular surface 108b is surrounded by third annular surface 108c (i.e., second annular surface 108b is disposed radially closer to punch portion 104 than third annular surface 108c). In other words, the first annular surface 108a, the second annular surface 108b, and the third annular surface 108c are concentrically arranged, with the second annular surface 108b being disposed midway between the first annular surface 108a and the third annular surface 108c in the radial direction "r." In particular, the first annular surface 108a, the second annular surface 108b, and the third annular surface 108c each continuously surround (i.e., radially surround) the punch portion 104. However, it is contemplated that at least one of the first annular surface 108a, the second annular surface 108b, and / or the third annular surface 108c may have separate (i.e., discontinuous) circumferential sections that collectively surround the punch portion 104.

[0017]

[0023] 4, the outer diameter (relative to the central axis "X") of the third annular surface 108c intersects (i.e., intersects) the outer peripheral surface 112 of the body portion 102 at the periphery 116 of the annular surface 108. That is, the outer diameter of the third annular surface 108c is adjacent to the body portion 102 at the periphery 116. The inner diameter (relative to the central axis "X") of the third annular surface 108c intersects the outer diameter (relative to the central axis "X") of the second annular surface 108b. Furthermore, the inner diameter (relative to the central axis "X") of the second annular surface 108b intersects the outer diameter (relative to the central axis "X") of the first annular surface 108a, which intersects (i.e., intersects) the outer peripheral surface 114 of the punch portion 104.

[0018]

[0024] As further shown, third annular surface 108c is planar (i.e., flat) and lies on an imaginary horizontal plane "P." Additionally, first annular surface 108a has a planar (i.e., flat) cross-section and is angled relative to imaginary horizontal plane "P." Specifically, first annular surface 108a may be convex with respect to imaginary horizontal plane "P." That is, first annular surface 108a slopes upward relative to imaginary horizontal plane "P" toward the radially inward direction of fastener 100. As shown in FIG. 4, first annular surface 108a has a convex angle θ (i.e., an angle less than 180° with respect to imaginary horizontal plane "P").

[0019]

[0025] This salient angle 9 provides a technical advantage by creating a suitable surface with which the metal panel can engage during installation. Specifically, conventional fasteners have a re-entrant angle between the annular surface and an imaginary horizontal plane. This configuration is acceptable for previously constructed metal panels. However, metal panels are now being manufactured from new lightweight materials (e.g., aluminum, steel, etc.) that have been strengthened (e.g., heat-treated) to improve their strength characteristics. While these new metal panels are thinner, lighter, and stronger, their relatively rigid substrates make them less susceptible to stretching during installation. That is, the substrate (i.e., metal panel) does not readily flow (i.e., plastically deform) during fastener installation, resulting in gaps (i.e., empty spaces) between the punch portion and / or annular surface and the mating substrate (i.e., metal panel). These gaps or voids reduce the attachment strength between the fastener and metal panel and ultimately result in an insufficient bond between them. The configuration of fastener 100 described herein, and specifically the configuration of the salient angle described above, significantly reduces or completely eliminates potential voids that may form between fastener 100 and the metal panel, i.e., there is no need for substrate material to flow into the undercut area formed by the angle between the annular face and the outer periphery of the punch portion.

[0020]

[0026] As shown, first annular surface 108a does not slope continuously downward from outer peripheral surface 114 of punch portion 104 to third annular surface 108c. Rather, as previously described, second annular surface 108b is disposed (radially) between first annular surface 108a and third annular surface 108c and gradually curves downward in the radial direction "r" (i.e., toward imaginary horizontal plane "P"). That is, second annular surface 108b, in cross section, follows a radius of curvature connecting the outer diameter of first annular surface 108a and the inner diameter of third annular surface 108c. Thus, due to the previously described curved design, second annular surface 108b has a concave cross section.

[0021]

[0027] In particular, by providing the curved second annular surface 108b between the first and third annular surfaces 108a, 108c in a planar (cross-sectional) plane, the radial footprint of the first annular surface 108a is reduced. That is, the first annular surface can maintain a convex angle θ with respect to an imaginary horizontal plane "P" without the convex angle having to continuously decrease down to the imaginary horizontal plane "P." Rather, the curved second annular surface 108b provides a smooth / efficient transition between the first and third annular surfaces 108a, 108c.

[0022]

[0028] However, it should be understood that second annular surface 108b may have a cross-sectional configuration other than curved. For example, second annular surface 108b may have a planar (i.e., flat) cross-section and be angled relative to imaginary horizontal plane "P." In another example (e.g., as shown in FIG. 7, described below), second annular surface 108b may have a planar (i.e., flat) cross-section and be disposed perpendicular to third annular surface 108c (i.e., perpendicular to imaginary horizontal plane "P").

[0023]

[0029] In summary, first annular surface 108a and second annular surface 108b define a rim 109 of annular surface 108, which projects axially outward from an imaginary horizontal plane "P" away from imaginary horizontal plane "P" and along central axis "X" toward second end face 104a of fastener 100. Additionally, rim 109 projects radially outward from an outer circumferential surface 114 of punch portion 104 (e.g., imaginary circumferential surface "C" shown in FIG. 5).

[0024]

[0030] Returning to FIG. 1 , the outer peripheral surface 114 of the punch portion 104 extends in the direction of the central axis "X" between the annular surface 108 of the body portion 102 and a distal periphery 117 of the punch portion 104 (i.e., the edge where the second end surface 104a and the outer peripheral surface 114 of the punch portion 104 intersect). Notably, the height of the punch portion 104 is less than the height of the body portion 102. Furthermore, the outer peripheral surface 114 of the punch portion 104 has a cylindrical contour. That is, the outer peripheral surface 114 of the punch portion 104 preferably has rounded corners that form an overall rounded surface. In other words, the outer peripheral surface 114 preferably is free of sharp edges that extend beyond an imaginary circumferential surface "C" (e.g., as shown in FIG. 5 ) that surrounds (i.e., encircles) the outer peripheral surface 114 of the punch portion 104.

[0025]

[0031] Because the outer periphery 114 of the punch portion 104 has a cylindrical profile without sharp edges, the likelihood of defects (e.g., cracks) occurring in the fastener 100 and / or the metal panel during installation is significantly reduced, and in some cases eliminated entirely. That is, sharp or pointed edges on the outer periphery 114 of the punch portion 104 are likely to crack due to the forces applied during installation. Thus, the fasteners 100 described herein do not have sharp or pointed edges on the outer periphery 114 of the punch portion 104, eliminating the aforementioned problems and reducing the likelihood of defects in the finished product.

[0026]

[0032] As shown, the outer periphery 114 of the punch portion 104 defines a plurality of spaced apart notches 118 that collectively surround the punch portion 104. In one embodiment, the notches 118 are equally spaced apart from one another and all have the same configuration. Specifically, each notch 118 has a concave surface relative to the outer periphery 114 of the punch portion 104. Alternatively, the notches 118 may have different spacings and / or configurations, such as only one notch 118 having a concave surface.

[0027]

[0033] 1 , the outer peripheral surface 114 of the punch portion 104 further includes a plurality of spaced-apart post portions 120, each post portion 120 being defined as a region of the cylindrically contoured outer peripheral surface 114 of the punch portion 104 between a pair of adjacently spaced notches 118. The plurality of spaced-apart post portions 120 collectively surround the punch portion 104, with each post portion 120 extending from the annular surface 108 to a distal periphery 117 of the outer peripheral surface 114 of the punch portion 104. Specifically, each post portion 120 is disposed between and separates a pair of adjacently spaced notches 118.

[0028]

[0034] As previously mentioned, in one embodiment, the plurality of cutouts 118 are shown to be equally spaced from one another. Specifically, it is the plurality of posts 120 that provide the even spacing between the plurality of cutouts 118. Accordingly, the plurality of post portions 120 are likewise equally spaced from one another. Furthermore, as previously mentioned, the outer peripheral surface 114 of the punch portion 104 has a cylindrical contour without sharp edges; this is a result of the posts 120 being disposed between and separating pairs of adjacently spaced cutouts 118. That is, if a pair of cutouts 118 were positioned directly adjacent to one another without any intervening surface, a cylindrical contour would not be provided between the pair of adjacent cutouts 118, resulting in sharp edges.

[0029]

[0035] Additionally, in one embodiment, the outer circumferential surface 114 of the punch portion 104 includes a plurality of bridge portions 122 that are spaced apart from one another and collectively surround the punch portion 104. Specifically, each bridge portion 122 is defined as a region of the cylindrical outer circumferential surface 114 of the punch portion 104 that is disposed between a pair of adjacently spaced post portions 120. Furthermore, each bridge portion 122 is axially disposed between a distal periphery 117 of the outer circumferential surface 114 of the punch portion 104 and a notch 118 surrounded by the pair of adjacently spaced post portions 120. In this manner, each bridge portion 122 connects a pair of adjacently spaced post portions 120.

[0030]

[0036] Turning to FIG. 5, one of the lugs 110 includes a contact surface 124 having a rounded profile (as shown in FIG. 1). That is, the contact surface 124 is curved (i.e., rounded laterally, side-to-side) relative to an imaginary axis extending in the radial direction "r" of the fastener 100. Preferably, the relative highest point of the contact surface 124 (relative to an imaginary horizontal plane "P") is at its midpoint, although other shapes are contemplated. In one embodiment, the contact surface 124 is configured to engage a metal panel to which the fastener 100 is to be installed and is sloped downward relative to the imaginary horizontal plane "P" in a direction radially outward of the fastener 100. As shown in the illustrated embodiment, the contact surface 124 is sloped continuously downward relative to the imaginary horizontal plane "P" in a direction radially outward of the fastener 100. This particular configuration (i.e., the contact surface 124 is sloped continuously downward in a radially outward direction) creates a suitable mating surface with the metal panel. That is, as previously mentioned, because the substrate (i.e., metal panel) does not readily flow (i.e., plastically deform) during installation, it is important to provide a fastener mating surface that does not require the substrate to flow into cavities and / or voids. Accordingly, contact surface 124 of fastener 100 described herein allows the substrate to efficiently flow and mate with annular surface 108 during installation. Furthermore, the configuration of contact surface 124 (i.e., its spatial orientation and having a rounded profile) eliminates the possibility of deformation of lug 110 during installation.

[0031]

[0037] The contact surface 124 has a first end 124a and a second end 124b. The first end 124a is disposed adjacent the outer peripheral surface 114 of the punch portion 104, and the second end 124b is disposed radially outward from the outer peripheral surface 114 of the punch portion 104. Preferably, the first end 124a is formed with the outer peripheral surface 114 of the punch portion 104. Notably, the second end 124b does not extend to the outer peripheral surface 112 of the body portion 102. That is, the second end 124b of the contact surface is not bounded by the outer peripheral surface 112 of the body portion 102. Rather, the second end 124b is radially disposed between an imaginary circumferential surface "C" (i.e., defining the boundary of the outer peripheral surface 114 of the punch portion 104) and the periphery 116 of the annular surface 108.

[0032]

[0038] As further shown in FIGS. 1 and 5 , each lug 110 has an outer surface 125 (distal from punch portion 104) that tapers in a radially outward direction toward an imaginary horizontal plane “P.” Like contact surface 124, outer surface 125 of lug 110 does not extend to the outer peripheral surface 112 of body portion 102. Rather, outer surface 125 extends from second end 124 b of contact surface 124 to second annular surface 108 b of rim 109. Notably, in one embodiment, outer surface 125 of lug 110 slopes continuously downward in a radially outward direction relative to imaginary horizontal plane “P” and has an inclination angle that allows the distal end of outer surface 125 to transition smoothly with the inner diameter of second annular surface 108 b. Furthermore, in contrast to contact surface 124, outer surface 125 of lug 110 is planar (e.g., as shown in FIG. 1 ). That is, outer surface 125 is not curved (i.e., not rounded laterally or side-to-side) relative to an imaginary axis extending in the radial direction "r" of fastener 100. However, it is contemplated that outer surface 125 may have a surface contour other than a planar surface.

[0033]

[0039] As previously mentioned, in one embodiment, contact surface 124 slopes continuously downward relative to imaginary horizontal plane "P" in a radially outward direction of fastener 100. This is because the surface of first end 124a of contact surface 124 is spaced a first distance d1 from imaginary horizontal plane "P" in a direction perpendicular to imaginary horizontal plane "P," which first distance d1 is greater than any other distance (e.g., d2) between contact surface 124 and imaginary horizontal plane "P" in a direction perpendicular to imaginary horizontal plane "P." As further shown, angle α between contact surface 124 and outer peripheral surface 114 of punch portion 104 is obtuse (i.e., angle α is greater than 90° and less than 180°).

[0034]

[0040] In one embodiment, as shown in FIG. 1 , each of the plurality of lugs 110 may have the same configuration. As further shown, each lug 110 is radially aligned with one of the plurality of notches 118. As such, a first end 124a of each lug 110 defines a notch 118 with which said lug 110 is radially aligned. Accordingly, the first end 124a of each lug 110 is radially disposed between a radial center point of the fastener 100 (i.e., the central axis "X") and an imaginary circumferential surface "C" that defines a boundary of (i.e., surrounds) the outer circumferential surface 114 of the punch portion 104. Furthermore, the total number of radially aligned lugs 110 and notches 118 may be determined according to the total number of surfaces of the outer circumferential surface 112 of the body portion 102, and each may be radially aligned with the outer circumferential surface 112. 1 and 2, fastener 100 includes a total of eight faces that collectively define outer circumferential surface 112 of body portion 102. Fastener 100 thus further includes a total of eight lugs 110 and notches 118, each lug 110 and notch 118 radially aligned with a respective one of the eight faces that define outer circumferential surface 112 of body portion 102. Alternatively, the total number of lugs 110 may differ from the total number of notches 118 and / or faces of outer circumferential surface 112 of body portion 102. Furthermore, lugs 110, notches 118 and / or faces of outer circumferential surface 112 of body portion 102 need not be radially aligned. For example, one lug 110 may be radially aligned with an edge formed between a pair of adjacent faces of outer circumferential surface 112 of body portion 102.

[0035]

[0041] All of the components of the fastener 100 described above, specifically the body portion 102, punch portion 104, rim 109, and lugs 110, are integrally formed with one another. That is, the body portion 102, punch portion 104, rim 109, and lugs 110 are all formed from the same material. However, the choice of material is not limited to this and other suitable materials may be used. Furthermore, the material of the fastener 100 preferably has a hardness greater than the hardness of the metal panel to which the fastener 100 is to be attached. If the fastener is a self-clinching stud, the stud is likewise integrally formed from the same material.

[0036]

[0042] In particular, the above-described configuration of fastener 100 provides increased tool life and reduced costs at the manufacturing level, improvements that are passed on to the consumer. Specifically, as previously described, rim 109 of annular surface 108 and lugs 110 that do not extend radially outward to outer periphery 112 of body portion 102 facilitate material flow (i.e., plastic deformation) of the substrate (i.e., metal panel) compared to conventional fastener designs. In particular, as previously described, the specific configuration of rim 109 and lugs 110 promotes material flow, resulting in observed force reductions (during installation) of up to 50%, or in some cases even greater, compared to conventional designs. Furthermore, the need for a reflective die is eliminated. Rather, a flat (i.e., planar) die can be used solely as a backstop during installation to reduce potential wear points on the tool. More specifically, a common weakness of conventional reflective dies (i.e., the raised portion) is eliminated, and the function of that raised portion is incorporated into fastener 100 via the configuration of rim 109. That is, rim 109 provides the same technical advantages as the previously described raised portion, but is formed as part of fastener 100 itself (rather than the die), and is therefore used only once. Therefore, because the die is flat (i.e., no longer a reflective die with raised portions) and serves as a backstop, the life of the flat die is significantly extended by 5 to 50 times the life of a conventional manufacturing die, a significant improvement with the new fastener design of the present invention. This results in longer tool life and reduced manufacturing costs.

[0037]

[0043] As briefly described above and with respect to FIG. 6 , fastener 100 may be a self-piercing and / or self-clinching stud. In such a configuration, fastener 100 includes a body portion 102 and a punch portion 104. A shank 126 extends outwardly from second end face 104 a of fastener 100 along central axis “X.” In other examples, shank 126 may extend outwardly from first end face 102 a of fastener 100 along central axis “X.” As shown, at least a portion of shank 126 may be threaded. Alternatively, shank 126 may be unthreaded.

[0038]

[0044] Turning briefly to FIG. 7, an alternative fastener 100 is shown. As previously discussed, the second annular surface 108b of the annular surface 108 need not have a radius of curvature. Rather, the second annular surface 108b may have a straight cross-section and extend perpendicular to the imaginary horizontal plane "P." Alternatively, it is contemplated that the second annular surface 108b may have a straight cross-section and be oriented at a predetermined angle (other than 90°) relative to the imaginary horizontal plane "P." As further shown in FIG. 7, the outer surface 125 of each lug 110 may have the same orientation as the second annular surface 108b relative to the imaginary horizontal plane "P." Specifically, as shown, the outer surface 125 extends perpendicular to the imaginary horizontal plane "P" and is coincident with the second annular surface 108b. However, it is contemplated that the outer surface 125 may be oriented at a predetermined angle (other than 90°) relative to the imaginary horizontal plane "P."

[0039]

[0045] The present invention has been described with reference to the exemplary embodiments set forth above. Other changes and modifications will occur to those skilled in the art upon reading and understanding this specification. It is intended that exemplary embodiments incorporating one or more aspects of the present invention include all such changes and modifications insofar as they come within the scope of the appended claims.

Claims

1. 1. A self-clinching fastener for attachment to a plastically deformable metal substrate, said self-clinching fastener comprising: a body portion having a central axis, the body portion including an outer peripheral surface extending in the direction of the central axis and annular surfaces extending in a direction perpendicular to the central axis, the annular surfaces including a first annular surface, a second annular surface, and a third annular surface, the third annular surface lying on an imaginary horizontal plane, the first annular surface and the second annular surface defining a rim projecting from the imaginary horizontal plane in the direction of the central axis; a punch portion coaxial with the central axis and extending from the body portion such that the annular surface surrounds the punch portion, the punch portion including an outer circumferential surface extending in the direction of the central axis; a plurality of spaced apart lugs surrounding the punch portion and projecting axially outward from the annular surface, one of the plurality of lugs inclined downwardly relative to the imaginary horizontal plane in a direction radially outward of the self-clinching fastener; the first annular surface extends radially outward from the outer circumferential surface of the punch portion, the second annular surface is radially disposed between the first annular surface and the third annular surface, and the one of the plurality of lugs is inclined downward to the second annular surface.

2. 2. The self-clinching fastener of claim 1, wherein an inner diameter of the first annular surface intersects the outer peripheral surface of the punch portion, an outer diameter of the first annular surface intersects the inner diameter of the second annular surface, and an outer diameter of the second annular surface intersects the inner diameter of the third annular surface.

3. 3. The self-clinching fastener according to claim 2, wherein the first annular surface has a planar cross-section and is angled relative to the imaginary horizontal plane, and the second annular surface has a curved cross-section such that the second annular surface continuously curves in a radially outward direction toward the imaginary horizontal plane.

4. The self-clinching fastener of claim 1 , wherein the second annular surface has a concave cross-section.

5. 2. The self-clinching fastener of claim 1, wherein the one of the plurality of lugs includes a contact surface having a first end and a second end, the first end being disposed adjacent to the outer circumferential surface of the punch portion and the second end being disposed radially outward from the outer circumferential surface of the punch portion.

6. 6. The self-clinching fastener according to claim 5, wherein the punch portion has a cylindrical contour lying on an imaginary circumferential surface, the first end being disposed radially between the central axis and the imaginary circumferential surface, the second end being disposed radially outward from the imaginary circumferential surface, and the contact surface sloping continuously downward from the first end to the second end.

7. The self-clinching fastener according to claim 5 , wherein said one of said plurality of lugs further includes an outer surface that continuously tapers in a radially outward direction toward said imaginary horizontal plane.

8. The self-clinching fastener of claim 7 , wherein the outer surface extends from the second end of the contact surface to the second annular surface.

9. 9. The self-clinching fastener of claim 8, wherein the contact surface has a rounded profile and the outer surface has a planar profile.

10. The self-clinching fastener according to claim 1 , wherein at least one of the body portion and the punch portion has a threaded through-hole formed therein.

11. The self-clinching fastener of claim 1 , wherein the rim and the one of the plurality of lugs are free from a boundary with the outer circumferential surface of the body portion.

12. The outer peripheral surface of the punch portion has a cylindrical contour, and the outer peripheral surface of the punch portion a plurality of spaced apart notches surrounding the punch portion; 2. The self-clinching fastener of claim 1, comprising: a plurality of spaced post portions surrounding the punch portion, each post portion being positioned between and spaced from a respective pair of adjacent spaced-apart notches.

13. The self-clinching fastener of claim 12 , wherein each post portion extends from the rim to a distal periphery of the outer circumferential surface of the punch portion.

14. 14. The self-clinching fastener of claim 13, wherein the outer peripheral surface of the punch portion further comprises a plurality of bridge portions surrounding the punch portion, each bridge portion connecting a respective pair of adjacent spaced apart post portions.

15. 15. The self-clinching fastener of claim 14, wherein each bridge portion is axially disposed between the distal periphery of the outer circumferential surface of the punch portion and a respective notch of the plurality of notches.

16. The self-clinching fastener according to claim 14, wherein at least one of the body portion and the punch portion has a threaded through-bore formed therein.

17. 1. A self-clinching fastener for attachment to a plastically deformable metal substrate, said self-clinching fastener comprising: a body portion having a central axis, the body portion including an outer peripheral surface extending in the direction of the central axis and annular surfaces extending in a direction perpendicular to the central axis, the annular surfaces including a first annular surface, a second annular surface, and a third annular surface, the third annular surface lying on an imaginary horizontal plane, the first annular surface and the second annular surface defining a rim projecting from the imaginary horizontal plane in the direction of the central axis; a punch portion that is coaxial with the central axis and extends from the body portion such that the annular surface surrounds the punch portion, the punch portion including an outer peripheral surface that extends in the direction of the central axis and has a cylindrical contour located on an imaginary circumferential plane; a plurality of spaced apart lugs surrounding the punch portion and projecting axially outward from the annular surface, one of the plurality of lugs inclined downwardly radially outward of the self-clinching fastener relative to the imaginary horizontal plane; the first annular surface extends radially outward from the outer circumferential surface of the punch portion, and the second annular surface is radially disposed between the first annular surface and the third annular surface; the first annular surface has a planar cross-section and is angled relative to the imaginary horizontal plane, and the second annular surface has a concave cross-section such that the second annular surface continuously curves in a radially outward direction toward the imaginary horizontal plane; the one of the plurality of lugs is angled downwardly to the second annular surface.

18. 18. The self-clinching fastener of claim 17, wherein the one of the plurality of lugs includes a contact surface having a first end and a second end, the first end disposed radially between the central axis and the imaginary circumferential surface, the second end disposed radially outward from the imaginary circumferential surface, and the contact surface slopes continuously downward from the first end to the second end.

19. 20. The self-clinching fastener of claim 18, wherein said one of said plurality of lugs further includes an outer surface that tapers continuously from said second end of said contact surface to said second annular surface.

20. 20. The self-clinching fastener of claim 19, wherein the rim and the one of the plurality of lugs are free from a boundary with the outer circumferential surface of the body portion.

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