Clinch fastener

Abstract

The clinch fastener includes a shaft defining a central axis and a head having an outer circumference that cooperates with the shaft. Multiple ribs are positioned beneath the head to engage with the workpiece. The multiple ribs extend radially outward from a displacement collar positioned close to the central axis of the clinch fastener toward the outer circumference of the head. Each of the multiple ribs includes at least a side wall and multiple sections that form a parametric profile for each rib. The clinch fastener includes a retaining ring that cooperates with the shaft and a retaining groove that cooperates with the shaft, positioned between the displacement collar and the retaining ring. The multiple ribs and displacement collar are configured to radially displace the workpiece material into the retaining groove and diffuse stress within the workpiece material once the fastener is secured to the workpiece.

Description

Technical Field

[0001] Cross - reference to Related Applications This application is a continuation - in - part of U.S. Patent Application No. 18 / 190,757, filed on March 27, 2023, which is hereby incorporated by reference in its entirety.

Background Art

[0002] Crimp fasteners are widely known in the fastener industry and are made in many different forms such as nuts, studs, pins, standoffs, etc. Regardless of the exact form, during installation, a crimp fastener is typically pushed into a pre - formed circular mounting hole in a workpiece. The workpiece is formed from a ductile host material that is softer than the crimp fastener. Once the crimp fastener is properly installed, it is prevented from rotating relative to the host material and also from axial movement. Thus, once installed, the crimp fastener becomes a substantially permanent part of the workpiece.

[0003] Crimp fasteners are used in certain applications to provide several advantages. For example, generally, crimp fasteners are more reliable and have improved holding power compared to either stamping threads or tapped threads. Crimp fasteners are used in applications where a metal sheet is too thin and / or too ductile to provide a secure fastening by any other suitable method and sufficient extrusion / pull - out (i.e., axial holding load) and torque are required. Even in applications where the metal sheet is thick enough to allow thread tapping, using a threaded crimp fastener instead of tapping threads in the metal sheet is often a more economical choice. Crimp fasteners can be installed during manufacturing to eliminate loose hardware during final assembly. Further, the use of crimp fasteners often allows for the use of thinner metal sheets and, as a result of their compact design and low profile, provides a neat appearance.

[0004] Clinch fasteners are often used in applications where components must be easily replaced and where loose hardware is inaccessible. Because clinch fasteners can be installed during metal fabrication, they can simplify and facilitate component installation and assembly operations, including on-site work.

[0005] As described above, when a clinch fastener is installed by pushing it into a mounting hole in a workpiece (such as a sheet of metal), the clinch fastener displaces the host material around the mounting hole, causing cold flow into the host material within the annular recess or undercut of the clinch fastener. The installation of a clinch fastener often creates a high-stress area in the host material (usually below the head of the fastener), which may result in either warping of the workpiece where the joint is adversely affected, or a final state of the clinch fastener that is not perpendicular to the workpiece after installation (i.e., the clinch fastener is slanted or bent). [Overview of the Initiative]

[0006] A clinch fastener for installation on a workpiece is described. The clinch fastener includes a plurality of ribs positioned below the head of the clinch fastener, which are specifically configured to displace the host material more uniformly than conventional clinch fasteners. To this end, in a cross section along a line extending from the central axis of the clinch fastener to the outer circumference of the head of the clinch fastener, each rib preferably provides a curved surface formed by multiple sections, with different radii or line segments defining each section. Preferably, the height of the ribs decreases as they extend to the outer circumference of the head of the clinch fastener. In addition, it is preferable, but not essential, that the ribs be equally spaced below the head.

[0007] One aspect of the present disclosure is to provide a clinch fastener configured to provide a more uniform stress distribution in a host material.

[0008] A clinch fastener includes a shaft defining the central axis of the clinch fastener and a head cooperating with the shaft, the head having an outer circumference. Multiple ribs are positioned below the head to engage with the workpiece when the clinch fastener is installed on the workpiece, and the multiple ribs extend radially outward in the direction from a displacement collar positioned close to the central axis of the clinch fastener to the outer circumference of the head. Each of the multiple ribs includes at least a side wall and multiple sections forming a parametric profile for each rib, including at least a first section positioned close to the shaft extending perpendicular to the central axis and an outer end adjacent to the outer circumference of the head.

[0009] The clinch fastener includes a retaining ring that cooperates with the shaft, and a retaining groove that cooperates with the shaft, positioned between the displacement collar and the retaining ring. Multiple ribs and the displacement collar are configured to radially displace the workpiece material into the retaining groove when the fastener is secured to the workpiece, thereby diffusing stress within the workpiece material.

[0010] One aspect of this disclosure includes at least two sections defined by different radii or multiple line segments.

[0011] Another aspect of the present disclosure includes having at least two of the sections be flat and at least one parallel to the head.

[0012] A further aspect of the present disclosure includes the fact that each rib decreases in height and increases in width as each rib extends in a direction toward the outer circumference of the head of the clinch fastener from the central axis of the clinch fastener.

[0013] A further aspect of the present disclosure includes the fact that each rib decreases in height and remains uniform in width as each rib extends in a direction toward the outer circumference of the head of the clinch fastener from the central axis of the clinch fastener.

[0014] One aspect of this disclosure includes the ribs being spaced equally apart below the head.

[0015] Another aspect of this disclosure includes the ribs being unevenly spaced below the head.

[0016] A further aspect of the present disclosure includes a retaining groove positioned below the head in close proximity to a plurality of ribs, and includes an annular recess positioned between the head and the shaft, in close proximity to the ribs.

[0017] One aspect of the present disclosure includes a clinch fastener comprising a nut having a threaded bore.

[0018] Another aspect of the present disclosure includes each of a plurality of ribs beginning in a section perpendicular to the central axis of the clinch fastener, the remainder of each rib comprising a plurality of sections, at least two of which are curved and defined by different radii or a plurality of line segments.

[0019] A further aspect of the present disclosure includes each of a plurality of ribs beginning in a section perpendicular to the central axis of the clinch fastener, and each rib having at least one curved section and one flat section.

[0020] One aspect of the present disclosure includes a plurality of flat sections, each of which a plurality of ribs collectively provides that the height of the rib decreases as the rib extends to the outer circumference of the head.

[0021] Another aspect of the present disclosure includes the case in which each of the ribs has a tapered sidewall.

[0022] A further aspect of this disclosure includes the case in which each of the ribs has an outwardly tapered side wall.

[0023] One aspect of the present disclosure includes a plurality of ribs configured to reduce warping of the workpiece material during installation as a result of the plurality of ribs being configured to provide radially focused material displacement of the workpiece material caused by the taper on the side walls of each rib.

[0024] Another aspect of the present disclosure includes each of the plurality of ribs beginning with a section perpendicular to the central axis of the clinch fastener, the remainder of each rib comprising a plurality of sections, the plurality of sections forming a parametric profile of the plurality of ribs.

[0025] A further aspect of this disclosure includes the fact that the parametric profile of each of the multiple ribs is defined by a number of parameters, including the rib height, the distance from the central axis of the clinch fastener to the end of the rib, and a predefined angle θ.

[0026] A clinch fastener for installation on a workpiece includes a shaft defining the central axis of the clinch fastener and a head cooperating with the shaft, the head having an outer circumference. A plurality of ribs are positioned below the head to engage with the workpiece when the clinch fastener is installed on the workpiece, each of the plurality of ribs extending radially outward in the direction from a displacement collar positioned close to the central axis of the clinch fastener to the outer circumference of the head of the clinch fastener, and having a non-planar surface having a curved surface and a parametric profile.

[0027] The clinch fastener includes a retaining ring that cooperates with a shaft, and a retaining groove that cooperates with the shaft and is positioned between a displacement collar and the retaining ring. Each of the plurality of ribs starts in a section perpendicular to the central axis of the clinch fastener, and the remaining portion of each of the plurality of ribs comprises a plurality of sections, at least two of the sections being curved and defined by different radii or a plurality of line segments. The plurality of ribs and the displacement collar are configured to radially displace workpiece material into the retaining groove and to spread the stress within the workpiece material when the fastener is fixed to the workpiece.

[0028] One aspect of the present disclosure includes that as each of the ribs extends in a direction from the central axis of the clinch fastener toward the outer periphery of the head of the clinch fastener, the height of each rib decreases and the width increases.

[0029] Yet another aspect of the present disclosure includes that as each of the ribs extends in a direction from the central axis of the clinch fastener toward the outer periphery of the head of the clinch fastener, the height of each rib decreases and the width remains uniform.

[0030] Another aspect of the present disclosure includes a plurality of ribs configured to reduce warping of the workpiece material during installation as a result of the plurality of ribs providing a radially converging material displacement of the workpiece material caused by the taper on the respective sidewalls of the ribs.

[0031] Yet another aspect of the present disclosure includes a plurality of ribs configured to provide a substantially circular recess in the workpiece material upon installation of the fastener onto the workpiece material as a result of the plurality of ribs providing a radially converging material displacement of the workpiece material caused by the taper on the respective sidewalls of the ribs and an inward material flow from the retaining ring into the retaining groove.

[0032] The above summary is not intended to represent all possible embodiments or aspects of the Disclosure. Rather, it is intended to illustrate some of the novel aspects and features disclosed herein. The above features and advantages of the Disclosure, as well as other features and advantages, will be readily apparent from the following detailed description of typical embodiments and forms for carrying out the Disclosure, in conjunction with the accompanying drawings and claims.

[0033] Herein, one or more aspects of the present disclosure are described by reference to the accompanying drawings. [Brief explanation of the drawing]

[0034] [Figure 1] This is a bottom view of a conventional clinch fastener as disclosed herein. [Figure 2] Figure 1 is a bottom perspective view of a conventional clinch fastener as disclosed herein. [Figure 3] This is a cross-sectional view taken along line 3-3 in Figure 4 of another prior art fastener as disclosed herein. [Figure 4] Figure 3 is a bottom perspective view of a conventional clinch fastener as disclosed herein. [Figure 5] Figures 3 and 4 show partial cross-sectional views (in the form of finite element analysis diagrams) of prior art clinch fasteners after they have been installed on a workpiece (i.e., host material) according to this disclosure. [Figure 6] This is a side view of a clinch fastener in the form of a stud according to one aspect of the present disclosure. [Figure 7] Figure 6 is a bottom perspective view of the clinch fastener shown in this disclosure. [Figure 8] Figures 6 and 7 are bottom views of the clinch fasteners shown in this disclosure. [Figure 9] These are cross-sectional views of the clinch fastener shown in Figures 6-8, taken along line 9-9 in Figure 6, according to this disclosure. [Figure 10]Figures 6 to 9 show partial cross-sectional views (in the form of finite element analysis diagrams) of the clinch fastener after it has been installed on the workpiece (i.e., the host material) according to this disclosure. [Figure 11] This is substantially the boxed portion 57 in Figure 9, after the clinch fastener has been installed against the workpiece (i.e., the host material), as annotated for illustrative purposes in this disclosure. [Figure 12] This is a cross-sectional view of the clinch fastener shown in Figure 8, taken along line 12-12 in Figure 8, according to the present disclosure. [Figure 13] This disclosure shows a bottom perspective view that is very similar to Figure 6, but instead of a stud, the fastener is in the form of a nut. [Figure 14] This is a perspective view of a clinch fastener showing the workpiece material received and engaged by one or more of the ribs on the head of the clinch fastener as disclosed herein. [Figure 15] This is a perspective view of a clinch fastener as disclosed herein, showing the workpiece material that is received and engaged between one or more of the ribs on the head of the clinch fastener. [Figure 16] This is a side view of a clinch fastener that engages with a workpiece material according to the present disclosure. [Figure 17] This is a cross-sectional view of a clinch fastener engaging with a workpiece material along line 16-16 in Figure 16, according to the present disclosure. [Figure 18A] This is a cross-sectional view of the clinch fastener, as shown in this disclosure, along line 17-17 in Figure 17, before installation and engaging with the workpiece material. [Figure 18B] This is a cross-sectional view of a clinch fastener engaged with a workpiece material at a first installation position along line 17-17 in Figure 17, according to the present disclosure. [Figure 18C] This is a cross-sectional view of a clinch fastener engaged with a workpiece material at a second installation position along line 17-17 in Figure 17, according to the present disclosure. [Figure 18D]This is a cross-sectional view of the clinch fastener as it engages with the workpiece material at its final installation position along line 17-17 in Figure 17, according to the present disclosure. [Modes for carrying out the invention]

[0035] The accompanying drawings are not necessarily to scale and may present somewhat simplified representations of various preferred forms of the disclosure disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes. Details regarding such features will be determined in part by the specific purpose, application, and environment of use.

[0036] The components of the embodiments of the disclosure described and illustrated herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description is not intended to limit the scope of the claimed disclosure, but merely to represent possible embodiments of the disclosure. Furthermore, while numerous specific details are provided in the following description to provide a complete understanding of the embodiments disclosed herein, some embodiments may be carried out without some of these details. Furthermore, for clarity, certain technical materials understood in the relevant art are not described in detail to avoid unnecessarily obscuring the disclosure. Moreover, the disclosure illustrated and described herein may be carried out even without elements not specifically disclosed herein.

[0037] The following detailed descriptions are essentially illustrative and are not intended to limit their use or application. Furthermore, they are not intended to be limited by any representation or implied theory presented herein. Throughout the drawings, corresponding reference numbers indicate similar or corresponding parts and features. The use of ordinal numbers such as 1st, 2nd, and 3rd does not necessarily indicate a ranked order, but rather may merely distinguish multiple instances of an action or structure.

[0038] Figures 1 and 2 show a prior art clinch fastener 10 consistent with that disclosed in U.S. Patent No. 5,513,933. Specifically, Figure 1 is its bottom view and Figure 2 is its bottom perspective view. Figures 3 and 4 show another type of prior art clinch fastener 11. Specifically, Figure 3 is its bottom view and Figure 4 is its bottom perspective view. Both the prior art fasteners 10 and 11 shown in Figures 1 to 4 include a head 12, a straight or flat rib 14 below the head 12, an annular recess 16 adjacent to the rib 14, and a shaft 18.

[0039] Both fasteners 10 and 11 include straight or flat ribs 14, and either fastener 10 or 11 can be used for illustrative purposes, but for illustrative purposes, Figure 5 is a partial cross-sectional view (in the form of a finite element analysis diagram) showing the conventional clinch fastener 11 of Figures 3 and 4 after the clinch fastener has been installed against the workpiece 20 (i.e., the host material). Figure 5 shows that, once installed, the straight ribs 14 move excess portions of the host material, causing a cold flow in the host material into the annular recess 16. This creates a high-stress region in the host material 20 below the head 12 of the clinch fastener 11, as the material is constrained by the shape of the ribs and is prevented from flowing both radially outward and perpendicular to the ribs. This can cause warping of the workpiece 20 (i.e., the surface of the workpiece 20 deforms adjacent to the clinch fastener 11 in areas such as 13), the clinch fastener 11 is not perpendicular to the workpiece 20 after installation, and there are other undesirable characteristics of the joint. For example, the configuration of each rib 14 tends to displace the workpiece material toward the adjacent rib, increasing the stress between the ribs 14.

[0040] Referring to the drawings, similar reference numerals correspond to similar or identical components throughout several drawings. Figures 6–8 are consistent with embodiments disclosed herein and illustrate elements of an embodiment of the clinch fastener 30 according to one aspect of the present disclosure. Figure 9 is a cross-sectional view of the clinch fastener 30 shown in Figures 6–8, taken along line 9-9 in Figure 6). As shown, the clinch fastener 30 is similar to the clinch fasteners 10 and 11 shown in Figures 1–4 and includes a head 32, an annular recess or retaining groove 34 adjacent to a rib 36, and a shaft 38. However, the clinch fastener 30 shown in Figures 6–9 includes a rib 36 below the head 32. The rib 36 is specifically configured to displace the host material more evenly than conventional clinch fasteners such as the clinch fasteners 10 and 11 shown in Figures 1–4. As shown in Figures 7 and 8, it is preferable, but not essential, that the rib 36 be evenly spaced below the head 32. For example, as shown in Figures 7, 8, and 12, each side wall 37 of the rib 36 may be tapered (although the side walls are shown tapered outward (i.e., relative to the adjacent rib 36), they may instead be tapered inward).

[0041] Figure 10 is a partial cross-sectional view (in the form of a finite element analysis diagram) showing a portion of the clinch fastener 30 from Figures 6-9 after it has been installed against the workpiece 40 (i.e., the host material). As shown, the clinch fastener 30, as a result of having special ribs 36, provides a more uniform stress distribution in the host material compared to the corresponding prior art clinch fastener 11 shown in Figure 5. Each of the special ribs 36, given its shape and configuration, tends to displace the workpiece material outward in the opposite direction to the adjacent rib. In this way, the stress is minimized between the ribs.

[0042] Preferably, each rib 36 of the clinch fastener 30 is substantially identical. The ribs 36 of the clinch fastener 30 shown in Figures 6 to 10 will be described in more detail with reference to Figure 11. Figure 11 is substantially the boxed portion 57 of Figure 9, annotated for illustrative purposes, and shows the clinch fastener 30 after it has been installed against the workpiece (i.e., the host material). In Figure 11, “Region A” is substantially a recessed area defined by a predetermined height and width based on the preferred performance of the retaining groove 34 configured to receive the cold flow of the host material 40 during the installation of the clinch fastener 30. Preferably, the height and width of “Region A” are specified by a standard, and the flow coefficient is specified by the ductility of the host material 40 into which the clinch fastener 30 is crimped during installation (i.e., the greater the ductility of the host material 40, the higher the flow coefficient). Dimension "Rh" is substantially the height of each rib 36 at its highest point, and this dimension is also preferably defined by the thickness of the workpiece. Dimension "Rd" is substantially the distance from the central axis 42 of the clinch fastener 30 to the end of each rib 36 (the central axis 42 is also identified in Figures 6-10). This dimension is preferably defined by the embedding and pull-through requirements.

[0043] As shown in Figure 11, in cross-section, each rib 36 is formed from multiple sections along a line extending from the central axis 42 of the clinch fastener 30 to the outer circumference of the head 32 of the clinch fastener 30 (i.e., to the end of each rib 36). Preferably, as shown in Figure 11, the height of the rib 36 decreases as it extends toward (but not necessarily toward) the outermost edge of the head 32 of the clinch fastener 30. Preferably, each rib 36 begins with a section perpendicular (or at least substantially perpendicular) to the central axis 42 of the clinch fastener 30. As shown in Figure 11, this section extends from point E (i.e., the corner of the recess) to point A and is identified as the vector "Vea". The area "Area B" is the product of both the height of each rib 36 at its highest point ("Rh") and "Vea" (i.e., the distance from point E to point A). Also, "Area A" = "Area B" multiplied by the flow coefficient.

[0044] therefore, "Area B" = "Rh" multiplied by "Vea", "Vea" = "Area B" / "Rh", and "Vea" = ("Area A" / Flow coefficient) / "Rh" That is the case.

[0045] The remaining portion of the rib 36 is preferably composed of multiple sections, at least two of which are curved sections defined by different radii or multiple short line segments. Preferably, one section extends from point A to point B as shown in Figure 11 and is defined by a radius identified in Figure 11 as “arc R1”. Preferably, the focus 46 or center of “arc R1” coincides perpendicular to point A (i.e., parallel to the central axis 42 of the clinch fastener 30), and the radius of the arc is approximately 10 to 60 degrees, as defined by the fastener size.

[0046] Preferably, another section extends from point B to point C (defined as vector Vbc), as shown in Figure 11, and is substantially flat or straight (or may be provided as arc-shaped). This begins at point B where the inclination of arc R1 from the horizontal is equal to θ. Arc R1 and Vbc are tangent at point B. Point C then has a linear relationship with point B, defined by a linear equation based on endpoints B and C in Figure 11. The horizontal dimension of point C from the central axis is directly related to the positions of point D and arc R2.

[0047] Another section extends from point C to point D (i.e., the outer end of rib 36), as shown in Figure 11, and is defined by a radius identified in Figure 11 as “arc R2”. Preferably, the focus 48 or center of “arc R2” coincides perpendicular to point B (i.e., parallel to the central axis 42 of the clinch fastener 30), and the radius of the arc is approximately 10–60 degrees. Preferably, “arc R2” begins at point C and ends at point D (i.e., the outer end of rib 36). Preferably, the focus 46, 48, or center of “arc R1” and “arc R2” (i.e., their vertical positions meaning how far they are from points A and B, respectively) depend on “Rh” and “point D”, and the profile of rib 36 is fully constrained from point A to point D.

[0048] Therefore, the multiple sections of the rib form a parametric profile of the rib, which is further defined by parameters including the height of the rib, the distance from the central axis of the fastener to the end of the rib, and a predefined angle θ as shown in Figure 11.

[0049] Figure 12 is a cross-sectional view of the clinch fastener 30 shown in Figure 8, taken along line 12-12 in Figure 8. As illustrated, preferably the sides 37 of the rib 36 are tapered or inclined at an angle α, which may vary based on manufacturing tolerances occurring during rib formation. For illustrative purposes only, in one aspect of the present disclosure shown in Figure 12, α is an angle (for example) of 20 degrees (including, meaning both sides) such that the inclination of the sides 37 of the rib 36 facilitates the flow of workpiece material between the ribs 36 during the crimping of the clinch fastener 30.

[0050] The configuration of the ribs 36 provides radially concentrated material displacement, thereby diffusing stress within the sheet material 40 and reducing warping during clinching. Preferably, the ribs 36 of the clinch fastener 30 are optimized to match the torsional stress distribution by reducing the amount of sheet material while maximizing the torsion (blind hole failure torque) of the clinch fastener 30. The configuration of the ribs 36 minimizes the volume of the rib profile radially outward as the force on the ribs increases as torque is applied after crimping, thereby forming a more uniform stress distribution on the ribs, as best shown in Figures 14 and 15. It will be understood that the ribs 36 may be equally spaced below the head 32 of the fastener 30, or alternatively, the ribs 36 may be unevenly spaced below the head 32 of the fastener 30. The profile of the rib 36 below the head 32 of the fastener 30 prevents the fastener 30 from rotating after it has been crimped onto the workpiece 40, as shown in Figure 18A.

[0051] The specially designed curved ribs also allow for the discharge of sheet material beyond the outer diameter of the rib. In contrast, conventional rib designs contain the sheet material and do not discharge it. While a rib design according to one aspect of this disclosure is not limited to use with soft joint materials, the rib design is ideal for use with soft joint materials (i.e., aluminum, etc.).

[0052] A rib design according to one aspect of this disclosure allows the use of high-strength clinch nuts and studs even when connecting with soft bonding materials. The rib configuration may also allow the use of thinner sheet materials. The rib configuration reduces distortion of the sheet material, resulting in a flatter sheeting area, and consequently, the clinch fasteners become more perpendicular to the sheet material after installation. Using the clinch fasteners disclosed herein reduces warping between installed clinch fasteners, and reduces distortion of the installation holes before and after assembly.

[0053] The rib configuration reduces the required distance between holes, minimizing edge effects during installation. The rib configuration reduces distortion in the sheet material, resulting in less hole distortion and improved performance. The rib configuration allows for clinching of thinner materials without the risk of deforming the mating material surface, enabling the use of higher crimping forces. The rib configuration also allows for crimping of fasteners with higher forces to ensure proper seating of the fasteners.

[0054] Figures 6 to 12 show one embodiment of the present disclosure of a stud, but the present disclosure can be used in many other embodiments, such as a nut 50 (having a threaded bore 51) as shown in Figure 13, which includes the ribs 36 described above. Further embodiments are entirely possible, while remaining within the scope of the present disclosure. In addition, although a specific number of ribs 36 are shown herein, any number of ribs can be provided on a given fastener while remaining within the scope of the present disclosure.

[0055] In one aspect of the present disclosure, each of the ribs 36 decreases in height and increases in width as it extends from the central axis 42 of the clinch fastener 30 toward the outer circumference 62 of the head 30 of the clinch fastener 30. Yet another aspect of the present disclosure includes each of the ribs decreasing in height and remaining uniform in width as it extends from the central axis 42 of the clinch fastener 30 toward the outer circumference 32 of the head 32 of the clinch fastener 30. It is understood that a rib profile in which the width may increase as the rib moves radially outward is given constant, variable, and ranged (maximum / minimum radius) as the rib progresses radially outward.

[0056] Furthermore, it is described that the rib 36 preferably comprises multiple sections, at least two of which are curved sections defined by different radii; however, instead, the rib 36 may comprise multiple flat sections that collectively provide the rib 36 to gradually decrease in height as it extends to the outer periphery of the rib 36 (i.e., to the end of the rib 36). It is also understood that the upper parts of one or more of the multiple ribs 36 may include rounded edges of varying radii tolerances to enhance the fastening of the clinch fastener to the workpiece material.

[0057] Referring here to Figures 16-18, a clinch fastener 30, shown in front of and installed against the workpiece 40, is illustrated and described. The clinch fastener 30 is configured to provide a more uniform stress distribution within the workpiece 40 when installed on the workpiece 40. The clinch fastener 30 includes a plurality of ribs 36 positioned below the head 32 to engage the workpiece 40 when the clinch fastener 30 is installed on the workpiece 40. The plurality of ribs extend radially outward from a displacement collar 60 positioned close to the central axis 42 of the clinch fastener 30 toward the outer circumference 62 of the head 32. The displacement collar 60 works in cooperation with the plurality of ribs 36, as shown in Figure 18B, to displace and feed the workpiece material into the retaining groove 34.

[0058] As described above, each of the multiple ribs 36 includes at least a side wall 37 and multiple sections forming a parametric profile, including at least a first section 64 positioned close to the displacement collar 60 and shaft 38 and extending perpendicularly to the central axis 42, and an outer end 66 adjacent to the outer circumference 62 of the head 32. The parametric or arched radial rib profile causes the workpiece material 72 to progressively flow radially outward along the side wall 37 and around the ribs 36, thereby reducing stress during the installation of the fastener 30 on the workpiece 40, and thereby minimizing deformation of the workpiece material 72. In addition, the symmetrical rib taper angles cause the workpiece material 72 to flow generally perpendicularly inward between the ribs 36, thereby reducing circumferential stress between the ribs 36.

[0059] The retaining ring 70 is positioned on the shaft 38 in close proximity to the retaining groove 34 and the displacement collar 60. In one aspect of this disclosure, the displacement collar 60 is positioned above the retaining groove 34, while the retaining ring 70 is positioned below the retaining groove 34. Alternative configurations and positions of the displacement collar 60, the retaining groove 34, and the retaining ring 70 are also intended by this disclosure.

[0060] As shown in Figures 18A to 18D, the retaining ring 70 is sized and positioned to cooperate with the retaining groove 34 to feed the displacement material 72 out of the workpiece 40 and provide a boundary or barrier that restricts the movement of the displacement material 72 while the clinch fastener 30 is installed in the workpiece 40. The multiple ribs 36 and displacement collar 60 are configured to radially displace the workpiece material 72 into the retaining groove 34 when the clinch fastener 30 is secured to the workpiece 40, thereby diffusing stress within the workpiece material.

[0061] Another aspect of the present disclosure includes a plurality of ribs 36 configured to reduce warping of the workpiece material 72 during installation as a result of the plurality of ribs 36 being configured to provide radially focused material displacement of the workpiece material caused by the taper on each side wall 37 of the ribs 36. In yet another aspect of the present disclosure, the plurality of ribs 36 are configured to provide a substantially circular recess in the workpiece material 72 when the fastener 30 is installed on the workpiece 40 as a result of the plurality of ribs 36 being configured to provide radially focused material displacement of the workpiece material 72 caused by the taper on each side wall 37 of the ribs 36, and inward flow of the workpiece material 72 from the retaining ring 70 into the retaining groove 34.

[0062] While specific embodiments of this disclosure have been shown and described, it is conceivable that those skilled in the art could devise various modifications without departing from the spirit and scope of this disclosure. For example, while embodiments have been described and illustrated as having a round shape and being used with circular holes, an elliptical version can be used with elliptical holes, while still remaining within the scope of this disclosure.

[0063] The modes and drawings or figures for carrying out the invention are supportive and illustrative of this teaching, but the scope of this teaching is defined solely by the claims. Although some of the best modes and other embodiments for carrying out this teaching have been described in detail, various alternative designs and embodiments exist for putting this teaching into practice as defined in the claims.

Claims

1. A clinch fastener for installation on a workpiece, A shaft defining the central axis of the clinch fastener, A head that cooperates with the shaft, the head having an outer circumference, A plurality of ribs positioned below the head to engage with the workpiece when the clinch fastener is installed on the workpiece, wherein the plurality of ribs extend radially outward from a displacement collar positioned near the central axis of the clinch fastener to the outer circumference of the head, and each of the plurality of ribs includes a plurality of sections that form at least a side wall and a parametric profile for each rib, and includes at least a first section positioned near the shaft that extends perpendicular to the central axis, and an outer end adjacent to the outer circumference of the head, A retaining ring that cooperates with the shaft, A retaining groove that cooperates with the shaft, positioned between the displacement collar and the retaining ring, Equipped with, The plurality of ribs and displacement collars are configured such that, when the fastener is fixed to the workpiece, they radially displace the workpiece material into the retaining groove, thereby diffusing stress within the workpiece material. The aforementioned clinch fastener.

2. The clinch fastener according to claim 1, wherein at least two of the sections are defined by different radii or a number of line segments.

3. The clinch fastener according to claim 1, wherein at least two of the sections are flat and at least one is parallel to the head.

4. The clinch fastener according to claim 1, wherein the height of each of the ribs decreases as each of the ribs extends in a direction toward the outer circumference of the head of the clinch fastener from the central axis of the clinch fastener.

5. The clinch fastener according to claim 1, wherein the ribs are spaced equally apart below the head.

6. The clinch fastener according to claim 1, wherein the ribs are unevenly spaced below the head.

7. The clinch fastener according to claim 1, wherein the retaining groove is positioned below the head in close proximity to the plurality of ribs and includes an annular recess positioned between the head and the shaft in close proximity to the ribs.

8. The clinch fastener according to claim 1, wherein the clinch fastener comprises a nut having a threaded bore.

9. The clinch fastener according to claim 1, wherein each of the plurality of ribs begins in a section perpendicular to the central axis of the clinch fastener, and the remainder of each rib comprises a plurality of sections, at least two of which are curved and defined by different radii or a plurality of line segments.

10. The clinch fastener according to claim 1, wherein each of the plurality of ribs begins in a section perpendicular to the central axis of the clinch fastener, and each rib has at least one curved section and one flat section.

11. The clinch fastener according to claim 1, wherein each of the plurality of ribs comprises a plurality of flat sections, collectively providing that the height of the rib decreases as the rib extends to the outer circumference of the head.

12. The clinch fastener according to claim 1, wherein each of the plurality of ribs has a tapered side wall.

13. The clinch fastener according to claim 1, wherein each of the plurality of ribs has an outwardly tapered side wall.

14. The clinch fastener according to claim 1, wherein the plurality of ribs are configured to provide radially focused material displacement of the workpiece material resulting from the taper on the side walls of each of the ribs, and as a result, the plurality of ribs are configured to reduce warping of the workpiece material during installation.

15. The clinch fastener according to claim 1, wherein each of the plurality of ribs begins in a section perpendicular to the central axis of the clinch fastener, and the remainder of each rib comprises a plurality of sections, the plurality of sections forming the parametric profile of the plurality of ribs.

16. The clinch fastener according to claim 14, wherein the parametric profile of each of the plurality of ribs is defined by a plurality of parameters including rib height, distance from the central axis of the clinch fastener to the end of the rib, and a predefined angle θ.

17. A clinch fastener for installation on a workpiece, A shaft defining the central axis of the clinch fastener, A head that cooperates with the shaft, the head having an outer circumference, A plurality of ribs positioned below the head to engage with the workpiece when the clinch fastener is installed on the workpiece, each of the plurality of ribs extending radially outward in the direction from a displacement collar positioned close to the central axis of the clinch fastener to the outer circumference of the head of the clinch fastener, and comprising non-planar surfaces having curved surfaces and parametric profiles, A retaining ring that cooperates with the shaft, A retaining groove that cooperates with the shaft, positioned between the displacement collar and the retaining ring, Equipped with, Each of the plurality of ribs begins in a section perpendicular to the central axis of the clinch fastener, and the remainder of each of the plurality of ribs comprises multiple sections, at least two of which are curved and defined by different radii or multiple line segments. The plurality of ribs and displacement collars are configured such that, when the fastener is fixed to the workpiece, they radially displace the workpiece material into the retaining groove, thereby diffusing stress within the workpiece material. The aforementioned clinch fastener.

18. The clinch fastener according to claim 15, wherein the height of each of the ribs decreases as each of the ribs extends in a direction toward the outer circumference of the head of the clinch fastener from the central axis of the clinch fastener.

19. The clinch fastener according to claim 15, wherein the plurality of ribs are configured to provide radially focused material displacement of the workpiece material resulting from the taper on the side walls of each of the ribs, and as a result, the plurality of ribs are configured to reduce warping of the workpiece material during installation.

20. The clinch fastener according to claim 1, wherein the plurality of ribs are configured to provide radially focused material displacement of the workpiece material resulting from the taper on the side walls of each rib, and inward material flow from the retaining ring into the retaining groove, so as a result, the plurality of ribs are configured to provide a substantially circular recess in the workpiece material when the fastener is installed on the workpiece material.

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