MXPA96004264A - Rivetable element, assembly, method of assembly and assembly remac - Google Patents

Abstract

The present invention relates to a method of attaching a fastener element to a plastically deformable metal panel, said fastener element including a radial flange portion and a generally cylindrical fastener portion axially protruding, said flange portion including an annular support surface generally surrounding said fastener portion, and said supporting surface comprising a generally annular groove axially entering said flange portion adjacent to and surrounding said fastener portion, said fastener portion having a radial groove axially spaced from the plane of said fastener surface. support of said flange portion, said method including the following steps: forming through said panel a generally cylindrical hole having a larger diameter than said fastener portion of said fastening element, but smaller than said supporting surface; in a set of e stampa including a stamp element having a hole aligned coaxially with said panel hole configured to receive said fastener portion of said fastener element with a smaller diameter than said support surface of the flange portion, said stamp element including protruding annular lip aligned coaxially with said axial groove of said fastener element, introducing said fastener portion of said fastener element through said panel hole in said stamp element hole and receiving said flange portion support surface against said panel next to said panel hole, then moving said support surface of said flange portion of the fastener element against said panel, then substantially simultaneously deforming said annular lip of the stamp element to said metal panel axially towards said slot in said portion of flange and radially towards said radial groove of said fastener portion to form a secure mechanical interlock between said fastener element and said metal panel.

Description

RIVETABLE ELEMENT, ASSEMBLY, METHOD OF ASSEMBLY AND RIVET STAMPING.

FIELD OF THE INVENTION This invention relates to self-fastening elements or fasteners, such as screws, bolts, nuts and the like, wherein the rivet element includes a shank or barrel portion and an integral head portion with a riveting portion on the underside of the head portion, next to the spike or barrel portion. The scope of this invention also relates to riveting stamps with a central hole that receives the shank portion of the riveting element, and, next to the hole, a riveting portion that deforms the piece of metal sheet or panel to which the riveting element is attached by inserting it into the riveting portion of the head of the fastener. Finally, the scope of this invention also relates to methods of joining riveting elements of the type described to a piece of metal sheet or plastically deformable panel. RELATED APPLICATIONS This application claims priority of the German patent application P 44 10 475.8 filed on March 25 of BACKGROUND OF THE INVENTION As described, the present invention relates to improved self-locking fasteners or fasteners having a spigot or spike portion. barrel and an integral head portion that can be permanently joined to a piece of metal sheet or panel by riveting. Elements of this type are already known, where the pin is generally threaded and inserted into a preformed hole in the piece of metal sheet. The head portion then supports one side of the metal part. The piece of metal foil or panel is then configured in an upsetting operation, such that the panel is physically molded by entering a small groove located in the peg of the element, directly adjacent to the support surface of the underside of the portion. of head, thereby fixing the element in a piece of metal foil or panel. The underside of the head, next to the spike, can include radial ribs, and the panel deforms on the ribs during installation, preventing relative rotation of the elements in the sheet metal panel. Such assemblies are frequently used in industrial production by the automotive and home appliances industries to secure another component to the assembly, which may consist of a second piece of metal sheet and fastener, such as a nut. The contact surface of the head portion is thus placed on one side of the first panel, in front of the second fastener element, such that the piece of metal foil is subjected to compression stress between the fasteners. However, in practice, the previously known self-tapping elements of this type were not fixedly attached to the metal part, so that the element was usually loosened during transport or storage before assembly, especially when the sheet part Metal is relatively thin, such as those now used by the automotive and home appliance industries. It is not uncommon for the riveting element to be lost or assumed in the panel to be unacceptable for further processing of the sheet metal part, as described above. The loosening of this type of self-stitching elements of the prior art sometimes caused inefficiency of the anti-rotation means provided, so that the element will rotate when the nut is mounted on the spigot portion, before tightening the nut on the bolt. These difficulties are a special problem in the construction of automobile bodies and other applications in which the head portion of the riveting elements is located in a closed cavity after installation, in which it is no longer accessible for repair. If the fastener element rotates freely in the panel or is lost in these conditions, the object that is manufactured, such as a car, can no longer be finished in regular production, but must be repaired, incurring a substantial expense. Obviously, these problems should be avoided, if possible. Another problem, especially when joining a riveting fastener to thin sheet metal panels, derives from the fact that the anti-rotation ribs must have a certain height; that is, the height of the ribs from the contact surface of the underside of the head portion should be sufficient to prevent rotation. When the piece of sheet metal is relatively thin, the ribs indentate the panel to such an extent that the full strength of the sheet metal part is no longer available, which can give rise to other problems. Another drawback of the self-locking male fastener elements of this type is that the small groove of the spigot portion that receives the panel material to prevent its removal is difficult to do, and thus the cost of the fastener is unnecessarily increased. In addition, this radial groove results in an undesirable reduction in the strength of the bolt or fastener, including its fatigue properties, resulting from the sharp edges and reduction of the cross-sectional area of the element's spigot portion. In addition, because of the dimensions of the slot, the element may also be insufficiently fixed to the sheet metal part, aggravating the tendency of the element to loosen in the sheet metal part or to fall off, as described above. Thus, a primary object of the present invention is to provide such a self-locking element that can be fabricated and fixed to a metal sheet panel at a relatively low cost, and where the risk of the element loosening or losing the piece of metal foil is reduced and preferably excluded. Another object is to provide a connection as strong as possible between the self-locking element and the panel, and a self-locking element or fastener which is suitable for joining to thin metal sheet parts, including non-ferrous metal sheet parts, such as aluminum or its alloys. COMPENDIUM OF THE INVENTION The self-locking or fastener element of this invention includes several novel features or elements that, in combination, result in an improved fastener and panel member and assembly, and reduces the cost of assembly. However, as will be understood, the novel features of this invention can also be used separately, especially when the function of a particular characteristic is desired or the function of another characteristic is not desired. As described above, the self-fastening element or fastener of this invention includes a spigot or barrel portion and an integral head portion extending generally transverse to the longitudinal axis of the spigot or barrel portion and providing an annular surface of contact on the underside of the head portion next to the spigot or barrel portion. In the preferred embodiment, the contact surface includes a plurality of concave cavities or closed fields that are limited by ribs extending outwardly from the spigot portion. In the most preferred embodiment, the cavities include a bottom wall that extends radially inward toward the spigot portion, and the ribs between the cavities extend longitudinally along the spigot portion. In the most preferred embodiment, the spigot portion further includes at least one radial groove or depression which is spaced apart from the plane of the contact surface of the head portion, preferably a distance equal to approximately the thickness of the metal foil part or panel to which the riveting element is attached. This depression or slot is most preferably spirally wound around the shank portion and may be the slot of the first thread when the shank portion is threaded. This design makes it possible, when riveting the element or fastener to the panel or piece of metal sheet, to deform plastically the material of the piece of metal sheet, by means of a suitable stamp arranged concentrically to the pin, introducing it in the cavities or concave peripherally closed fields located on the underside of the head portion and radially on the depression or slot located in the spigot portion without essentially thinning the sheet metal part. further, the self-locking element or fastener of this invention prevents rotation of the fastener in the panel without weakening the sheet metal part, thus avoiding the problems associated with radial protruding ribs of conventional self-locking elements of this type. Further, since the ribs between the concave cavities extend longitudinally along the spigot portion, the antirotation is achieved not only by the material introduced into the concave fields, but also by the positive connection between the longitudinal ribs in the portion of the concave cavities. spike and the piece of metal foil. As a result, the torsional strength of the fastener in the panel is considerably improved. By joining the element to the panel, the sheet metal part does not necessarily reduce its thickness, and the depression or groove of the spigot portion may be located further away from the underside of the head contact surface than would be possible with the radial groove according to the prior art, so that the depression can be formed more easily. In addition, the shape of the depression or groove can be formed more neatly than when the groove is located immediately adjacent to the head as in the prior art, ensuring that the metal foil deforms more easily by entering the depression, thereby generating a better resistance to the removal of the fastener and loss of the element of the sheet metal part, as described above.

Another advantage of the self-fastening fastener element of this invention is the position of the longitudinal ribs and the depression or radial groove in an enlarged portion of the dowel next to the head. Due to this design, the depression weakens the self-locking element less, allowing a more complete utilization of the nominal strength of the fastener element and the improvement of the fatigue properties of the element. In addition, the resistance to torsion of the element in the panel is also improved. However, it is particularly important that the material flow performance of the sheet metal part can be improved by attaching the fastener to the panel. Preferably, the preformed or prefabricated hole in the piece of metal sheet has a diameter that allows the insertion of the pin portion without deterioration. The large diameter portion of the shank portion preferably has a slightly larger diameter than the opening or the panel hole, so that the diameter of the hole widens during installation of the self-locking element in the panel, which provides additional material which can be introduced into the cavities or peripherally closed concave fields of the head or in the radial depression of the spigot portion. It is also possible to deform conically the piece of metal sheet next to the hole according to the description of co-pending US application Serial No. 343,724, filed on November 22, 1994, the disclosure of which is incorporated herein by reference. The shank portion of the self-locking element is then received through the conical hole, through the apex of the conically shaped depression, and the panel is then flattened by moving the head portion against the panel, thus having more material available. to form a tight joint between the element and the sheet metal part. The depression or spiral groove of the spigot portion can be formed by a threaded slot, namely the continuation of a threaded portion located in the spigot of the self-locking element. In this way, the depression is formed in the same operation when the thread is formed or cut in the spigot portion. This leads to a considerable cost saving in the manufacture of the self-healing fastener element, as well as to a clean spiral depression. If the longitudinal ribs are formed in the shank portion, adjacent to the head, in the portion of smaller diameter of the spigot during the thread embossing operation, which is preferred, the depression or slot can be easily deformed during the operation of the thread, so that all the threads end in the depression. However, alternatively, it is possible to form the ribs after the thread embossing operation in a separate step, for example, also in a thread embossing operation. In this case, the depression would be divided into several sections by the nerves. In addition, the relief portion between the ribs extending along the axis would not enter the depression to avoid interference with the deformation of the panel to the depression.

The exception would be when the self-locking elements are used for the union of an electrical terminal. In that case, the ribs would produce a desirable notch effect in the terminal hole, which would be beneficial to create a good electrical contact. The spiral depression may represent one or two threads and may also be in the form of thread sections, especially when the depression is configured as a multiple start thread, which would be useful for the rivet element of this invention. The depression or spiral groove still has another advantage compared to a circular radial groove. After prolonged installation and use, an additional torque may be required to remove the nut from the stud portion of the stud due to contamination or corrosion. Said high pair, however, will cause the riveting element to be pushed against the metal sheet part due to the spiral shape of the depression, so that greater torsional strength is obtained. Although a spiral groove is preferred for the reasons discussed above, it is also possible to use a circular groove or depression whose pitch is zero degrees. This shape may be preferable when the spigot portion of the self-tapping element is not threaded, such as a spindle shaft. However, the depression or groove should be spaced from the underside of the head, as described above. As will be understood, the zone 1 of the cavities or closed fields in relation to the contact area can be selected so that the torsional strength is optimal. Thus, it is possible to use the self-stitching element of this invention in conjunction with softer metals, including aluminum alloy panels, which are increasingly used in automotive applications. In such applications, the material of the self-healing element can be selected to prevent galvanic corrosion, where the self-locking element can be made of aluminum alloy. As described, the stamp element used by the self-locking element assembly of this invention includes a hole that receives the pin or barrel portion of the fastener, and the hole preferably has a crown to deform the panel metal toward the cavities or confined fields of the head portion of the element. As will be understood, the lower surface of the groove on the underside of the head portion will depend on the shape of the stamp used. In addition, the self-locking element may be a male fastener element, such as a bolt or bolt, or a female element, such as a nut, where the spigot portion is replaced by an annular barrel portion. The method of this invention thus includes forming a hole in the piece of metal sheet by punching, punching or the like; introducing the shank portion or barrel of the self-tapping element through the hole in the piece of sheet metal or panel; plastically deforming the material of the sheet metal part near the hole in the panel to at least partially fill the cavities of the lower side of the head and radially inwardly to the groove or depression of the shank portion of the element of the head. autosujection. Other advantages and meritorious features will be better understood with the following description of the preferred embodiments, the appended claims and the drawings, of which a brief description follows. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevational view of an embodiment of the self-stitching element of this invention, partially in cross section for reasons of clarity. Fig. 2 is an end view of the self-stitching element shown in Fig. 1. Fig. 3 is an enlarged partial cross-sectional view of the self-stitching fastener element shown in Fig. 1. Fig. 4 is an end view in section. partial cross section of figure 3 in the direction of the point 4-4 arrows. Figure 5 is a schematic illustration of an installation apparatus or placement head of this invention illustrating the first step of the installation method of this invention. Figure 6 is a partial cross-sectional view similar to Figure 5 after installation of the self-locking fastener element shown in Figure 5. Figure 7 is a detailed partial cross-sectional side view of the rivet stamp shown in FIG. Figures 5 and 6. Figure 8 is a side partial cross-sectional view of the self-stitching fastener element shown in Figures 1 to 4 installed on a piece of metal sheet. Figure 9 is an enlarged partial cross-sectional view of Figure 8 in the area indicated by the reference numeral 9. Figure 10 is a side partial cross-sectional view similar to Figure 1 of a second embodiment of the fastener element of FIG. Self-tapping shown in Figure 1, where the spike portion of the riveting element is unthreaded. Figure 11 is an end view of the fastener element shown in Figure 10. Figure 12 is a partial cross-sectional view of the rivet member shown in Figure 10. Figure 13 is an enlarged partial cross-sectional view of the Figure 12. Figure 14 is a side partial cross-sectional view of another embodiment of the self-stitching element of this invention in the form of a female element.

Fig. 15 is an end view of the self-stitching element shown in Fig. 14. Fig. 16 is an enlarged partial cross-sectional side view of the fastener element shown in Fig. 14. Fig. 17 is a partial cross-sectional view of end of figure 16 in the direction of the arrows from point of view 17-17. Figure 18 is a partial cross-sectional side view of another embodiment of the self-stitching element of this invention in the form of a fastening element '! -16 threaded female installed in a panel. And Figure 19 is an enlarged view of the fastener element shown in Figure 18. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Figure 1 is a side elevational view of an embodiment of the rivet element 10 of the invention in the form of a threaded pin having a head portion 12 and a shank portion 16 which is threaded on the outside at 14. As shown in more detail in Figures 2, 3 and 4, the lower face 18 of the head portion 12 has a concave contact surface which includes cavities or peripherally closed fields 20 which are limited in part by ribs 22 extending radially outwardly from the spigot portion 16, as shown in Figures 2 and 4, and which are continuous with rib portions 24 that are axially extend along the head portion 16, as shown at 24 in Figure 3. As shown, the ribs 24 extend from the head portion to 26, up to the depression or slot 28 which in the embodiment described is the first spiral groove of the threaded portion 14 of the pin. As shown in Figures 2 and 4, the closed cavities or fields 20 are limited on their outer radial side by the surrounding annular peripheral surface 30 of the head, the ribs 22 defining the radial surface which is continuous with the annular surface 30. The radial interior of the cavities 20 is defined by a cylindrical peripheral surface 32 of the spigot portion. As shown in Figure 3, the rib portions 22 extend obliquely to the plane 31 defined by the underside of the head portion 12 or recessed from said plane (31) in such a way that the ribs do not protrude from said recessed plane. next to the spigot portion of the self-tapping element. It will be understood, however, that the rib portions 22 may be located in the same plane 31 as the peripheral surface 30. The peripheral surface 30, as well as the surfaces adjacent to the tang 22, form the actual contact surface of the portion. 12. In this embodiment, the cavities or closed fields 20 are generally quadratic or rectangular, which, in practice, is a favorable form. It will be understood, however, that the cavities may have different shape within the scope of the present invention. In the embodiment described in Figures 2 and 4, the rib portions 22 of the contact area of the lower side 18 of the head portion 20 expand radially outwards as shown in Figures 2 and 4. In addition, the portions of rib 22 extend continuously and without interruption to the outer peripheral surface 30 of the head portion. In the described embodiment, there are eight rib portions 22, the preferred number of rib portions oscillating between six and eight. As is evident from FIGS. 1 and 3, the closed cavities or fields 20 have their greatest axial depth measured axially in the direction of the axial line 35 (in FIG. 1) next to the spigot portion 16. The contact surface of the lower side 18 of the head 12 includes primarily the rib portions 22 and the outer peripheral surface 30. The lower surfaces of the cavities 20 can be used as a contact surface by deformation of the metal foil portion to the cavities or fields closed. The contact surface is thus relatively large, so that the rivetable element 10 can be used with relatively soft sheet metal parts without fear of a critical surface pressure occurring. In the most preferred embodiment, the lower surfaces of the closed fields are located on a conical dome surface with an inscribed angle of preferably between about 130 ° and 140 °. Said tapered angle is referred to in Figure 3 as angle a. Thus, the rivetable element 10 of the embodiment shown in figures 1 to 3 includes a centering depression which guarantees valuable high-quality guidance of the element. A conical pilot tip 36 located at the end of the shank portion 16 not only provides for the receipt of a threaded fastener or nut in the inlet shank portion, but also guides the self-tapping element in the upsetting head when it is introduced in the sheet metal part, as described below. The upsetting or mounting operation is illustrated schematically in FIGS. 5 and 6. The installation tool 40 shown in FIG. 5 includes an upsetting head or installation 38 having a press-fit punch 42 that can be moved in the direction of the arrow 43. The arrow 42 indicates the direction of advancement of the self-locking element 10 in the installation head. The self-locking elements 10 are supplied individually to the installation head 38. The self-locking element 10 shown in FIG. 5 advances by gravity, compressed air or the connecting punch 42 through the hole 44 of the installation head until the The head portion 12 of the element contacts the ball 48, which is pushed elastically into the hole 44 by the spring 46. In practice, three spring-loaded balls are provided, arranged at intervals of 120 ° around the longitudinal axis 50 of the head of the head. installation 38. In the station of figure 5, the piece of pre-punched metal sheet 52 in which the element 10 will be installed, is retained between the installation head 38 and a rivet stamp element 54 of a lower tool 56. The shank portion 16 of the self-locking element 10 is provided with a threaded portion 14 that is partially received through the preformed hole in the metal sheet part. and through an axially aligned cylindrical centering hole 60 in the rivet stamp 54. The rivet stamp 54 is releasably retained within a hole 57 of the lower tool 56 and is supported on a die 59 in a lower press plate 61. In the next station of the upsetting operation, the pressure / joint punch 42 provided in the installation head 38 moves further down, causing the head portion of the element to pass the balls 48 pushed by spring. During this movement, the surrounding crown area 64, represented in FIG. 7, of the rivet stamp is inserted into the material of the metal sheet piece by deforming the metal sheet into the V-shaped slot 23 which includes the recesses or closed fields 20 and the recess 28, thereby creating a firm riveted connection between the riveting element 10 and the metal sheet part 52, forming a secure assembly. The preferred embodiment of the rivet stamp 54 includes a crown area 64 surrounding the hole 58, as shown in Figure 7. That is, the annular crown-shaped area of the rivet stamp defines a wavy end face. with peaks 72 and valleys 74 extending in the axial direction. In practice, the embossed peaks 72 deform and introduce the material of the sheet metal part into the cavities or concave fields 20 located on the lower side 18 of the head portion of the element, while the valleys 74 make contact with the sheet metal piece in front of the ribs 22 extending radially outwards, so that there is no pronounced thinning of the sheet metal part in the region of the ribs. As the sheet metal material is deformed between the rivet stamp and the underside of the head portion 12 of the element 10, the material of the metal sheet is also made to flow into the depression 28, thereby forming the desirable positive bond. Unexpectedly, it is not necessary to angularly align the element 10 in the peaks and valleys of the crown portion 64 because the element will rotate to assume a position in which the peaks 72 of the rivet stamp 54 are aligned with the concave cavities or fields. That is to say, the necessary alignment takes place by means of a slight automatic twisting of the element during the installation operation. The crown area 64 of the stamp element 54 forms a slot 80 in the metal sheet piece 52, as shown in FIGS. 8 and 9. This slot 80 may be interrupted, but extends around the tang portion 16 of the blank. Self-tapping fastener on the side 71 of the metal foil piece remote from the head 12 of the fastener, as shown in Figures 8 and 9. As will be understood, said groove 80 includes a corrugated bottom surface; however, the peaks of the corrugated bottom surface should not protrude beyond the underside 71 of the metal foil part in order to obtain a clean seating of the nut or other object to be attached to the sheet metal part. An exception is when the object to be attached to the sheet metal part is an electrical terminal. In such a case, the peak areas of the corrugated bottom surface may protrude beyond the bottom side 71 of the metal sheet part to obtain a greater contact surface pressure at the terminal, providing a better electrical contact. As will be understood, the self-stitching element of this invention can be a female fastener, such as a nut, or any other type of element that can be permanently attached to a piece of metal foil, such as a metal panel used in the automotive industries and appliances. Figures 10 to 13, for example, illustrate an element 110 in the form of a spindle. Given the similarities of the element 110 with the self-healing element 110 described above, similar reference numerals are used to designate the item shown in Figures 11 and 12 and in all other embodiments described below, to avoid unnecessary repetition of the description. The differences between the axle journal 110 shown in Figures 10 to 13 and the threaded pin 10 are not very significant. The main differences are found in two areas. First: the spigot portion 116 of the element 110 includes a cylindrical support surface 115, like the unthreaded spigot portion. It will be understood, however, that the cylindrical support surface 115 may include a threaded section in order to tighten the sheet metal part with an appropriate nut or a nut and washer assembly between the head portion 112 and the nut or for Fix an internal bushing of the object mounted on the axle journal against the axial displacement in the longitudinal direction of the element. Second: the slot 128 to which the metal foil is deformed is an annular groove, instead of a spiral groove thread like the groove 28 of Figure 3. The annular or circular groove 128 can be considered as a spiral groove with a inclination angle equal to zero degrees. It can be seen in Figure 12 that said surrounding groove 128 is disposed at a distance approximately equal to the thickness of the metal sheet from the contact surface 118 of the head 112 and that said distance is substantially greater than the similar grooves provided in the elements. of clamping described in the prior art.

Thus, it is easier to form the slot or depression in the spigot portion than when the slot is located immediately adjacent to the head portion 112, as described in the prior art. As described above, however, the slot 128 can be formed as a thread groove, as shown at 28 in FIGS. 1 through 4. The groove 128 is formed in this embodiment in the portion support zone. of spike next to the head portion 112, which is possible and is preferred with the element shown in FIGS. 1 to 9. The positive connection between the element 110 and a piece of metal foil is carried out in exactly the same way as described above with respect to FIGS. 10 with the threaded bolt 10. The riveting element of this invention can also be in the form of a female element, such as a support bushing 210 shown in FIGS. 14 to 17, and the nut holder 310 shown in FIGS. 18 and 19. The support sleeve 210 shown in FIGS. 14 to 16 includes an axial through hole 282 having a central cylindrical portion 282 that provides the support surface. In Figure 14, the upper portion of the hole 282 includes a centering hole 234 having a diameter somewhat larger than the support surface 282. The lower portion of the hole 284 includes a widened portion 286 which serves to prevent deformation of the tang portion of the nut due to plastic deformation of the sheet metal part to the fields or cavities 220 and the depression 228, which would result in the constriction of the cylindrical hole 282, which would prevent the support piece from being inserted in element 210. In this embodiment, the head portion is a radial flange 212 and the spigot portion is an annular cannon portion 216. As discussed above, similar elements are numbered as described above with respect to Figures 1 to 13. As shown in figures 18 and 19, the element The riveting r 310 may be provided with an internal thread 388, such that the element 310 can be used as a nut holder after installation in a metal part 352, as shown. This embodiment is very similar to the support bushing 210 shown in FIGS. 14 to 17, except that the hole 388 is threaded. The head portion 312 is in the form of a radial flange portion and the spigot portion 316 is a tubular or annular barrel portion that includes a radial depression. It will be understood, however, that the annular barrel portion can also be extended and tapped externally. The threaded hole 388 can then receive a threaded screw (not shown) to join another object or element to the metal part 352. By using a female element 310 according to FIGS. 18 and 19, a cup-shaped depression 392 may be preferred in FIG. the sheet metal part 352, which allows assembly at the level of an object on the lower side 371 of the sheet metal part. Said cup-shaped depression 392 can be created in the metal foil part 352 by a previous operation when the sheet metal part is pierced or by a special configuration end face of the rivet stamp shown in Figures 5 and 6 , as experts in the field will understand. The female riveting elements shown in FIGS. 14 to 19 can be attached to a metal part with the installation apparatus shown in FIGS. 5 and 6, as described above. As will now be understood, the self-healing element and the installation method of this invention can be used in a wide range of applications, including male and female elements, fasteners and the like. In addition, the various improvements described herein may be used in combination or separately to produce an improved fastener and element assembly. For example, the peripherally closed cavities or fields (20, 120, etc.) provide the fastener assembly with antirotation means. Thus, it is possible not to use the cavities in a fastener assembly where antirotation means are not desired. The method of this invention can then include forming through the panel a hole of greater diameter than the stud or barrel portion of the elements, supporting the panel in a stamp assembly having a hole aligned coaxially with the panel hole configured for receiving the stud or barrel portion of the fastener element, but with a smaller diameter than the head portion or flange of the support surface, wherein the stamp element includes a protruding annular lip aligned coaxially with the slot in the rivet element. In the preferred embodiment, the groove 23 is generally V-shaped and extends to the flange portion or head of the element next to the barrel or stud portion, as shown in Figure 3. The method then includes introducing the portion of stud or barrel of the element through the panel hole in the hole of the stamp element, receiving the supporting surface of the head portion or flange against the panel, next to the panel hole. The method then includes moving the support surface of the element against the panel, causing the annular lip of the stamp element to substantially simultaneously deform the panel metal by inserting it into the axial slot and radially into the radial slot of the element. In the most preferred embodiment, the radial groove is the first thread of a threaded portion of the fastener, as shown in Figure 3.; however, the groove can be annular, as shown at 128 in Figure 10. The element and metal piece or panel assembly thus includes a self-locking element, as described, and a metal part or panel, where the portion of The stud or barrel of the element is received through an opening or hole in the metal part or panel, and the panel or metal part is deformed to the V-shaped annular groove surrounding the stud or barrel portion and the radial groove located in the asparagus or cannon portion. In the most preferred embodiment, the panel portion is deformed more and simultaneously to the confined cavities or fields circumferentially spaced, forming a very secure assembly that prevents all removal and rotation of the self-locking element in the panel. In the most preferred embodiment, the self-stitching member is a fastener that can be used to attach a second element to the panel. In the embodiment 10 described in FIGS. 1 to 4, the fastening element is a male fastening element, such as a screw or bolt 10. In the embodiment 110 shown in FIGS. 10 to 13, the fastening element 110 is a spindle shaft, wherein the cylindrical portion of stud 15 receives a female element with a cylindrical hole, which is attached to the stud portion of the fastener element. In the embodiment 210 described in Figures 14 to 17, the fastener element 210 is a support bushing that receives a male element having a cylindrical surface that is received in the hole 82 of the bushing. Finally, in the embodiment 310 shown in FIGS. 17 and 18, the fastening element is a nut holder, which receives a screw or bolt for attaching an element to the panel. Having described the preferred embodiments of the riveting element, the joining method and the assembly of this invention, it will be understood by those skilled in the art that various modifications may be made to the described embodiments within the scope of the following appended claims.

Claims (33)

1. CLAIMS 1. A method of attaching a fastener element to a plastically deformable metal panel, said fastener element including a radial flange portion and a generally cylindrical fastening portion axially protruding, said flange portion including an annular support surface generally surrounding said fastener portion, and said supporting surface comprising a generally annular groove axially entering said flange portion adjacent to and surrounding said fastener portion, said fastener portion having a radial groove axially spaced from the plane of said support surface of said fastener. flange portion, said method including the following steps: i "forming through said panel a generally cylindrical hole having a larger diameter than said fastener portion of said fastener element, but smaller than said support surface; a stamp set that includes a stamp element having a hole aligned coaxially with said panel hole configured to receive said fastener portion of said fastener element with a smaller diameter than said supporting surface of the flange portion, said stamp element including a protruding annular lip aligned coaxially with said axial groove of said fastener element; introducing said fastener portion of said fastener element through said panel hole in said stamp element hole and receiving said supporting surface of the flange portion against said panel adjacent said panel hole; then moving said support surface of said flange portion of the fastener element against said panel, then substantially simultaneously deforming said annular lip of the stamp element to said metal panel axially towards said slot in said flange portion and radially towards said radial slot of said fastener portion to form a secure mechanical interlock between said fastener element and said metal panel. The method of attaching a fastener element to a metal panel as defined in claim 1, characterized in that said fastening element is a male threaded element, said method including screwing said fastener portion of said fastener element adjacent said groove axially of said flange portion, a thread next to said axial groove defining said radial groove, said method further including deforming said panel radially to said thread adjacent said groove in said flange portion. 3. The method of attaching a fastener element to a metal panel as defined in claim 1, characterized in that said groove of said support surface of the fastener element is generally V-shaped in cross section, including a cylindrical surface that is extends generally axially, and a surface extending radially from said surface at an acute angle toward said support surface, and said groove including ribs extending along said groove surface and continuing along said radial surface defining generally closed cavities, said method including deforming said panel substantially to fill said V-shaped groove against the surface of said groove surrounding said ribs, thus avoiding relative rotation of said fastener element in said panel. 4. The method of attaching a fastener element to a metal panel as defined in claim 1, characterized in that said flange portion of the fastener element includes an axial hole opposite and aligned coaxially with said fastener portion, said method including positioning said fastener portion. fastener element in an installation head having a plunger passage aligned coaxially with said panel hole and a plunger alternating in said plunger passagesaid piston having a positioning pin and said method including placing said positioning pin in said hole of the flange portion before moving said support surface of said flange portion of the fastening element against said panel, said positioning pin aligning said fastener element relative to said stamp element. A self-fastening fastener element including a radial flange portion and a generally cyrical fastening portion axially protruding, said flange portion including an annular support surface generally surrounding said fastener portion, and said support surface including generally annular groove extending axially to said flange portion adjacent to and surrounding said fastener portion, said axial groove having a generally V-shaped cross section, including a generally cyrical axial surface defined by an outer surface of said fastener portion, and a radial surface extending from said axial surface towards said supporting surface at an acute angle, said axial groove further including a plurality of spaced ribs extending axially along said axial surface and continuing radially along said radial surface defining cavities generally closed, circumferentially spaced. The self-stitching fastener element defined in claim 5, characterized in that said fastener portion of said fastener element further includes a radial groove axially spaced from said annular groove. The self-stitching fastener element defined in claim 5, characterized in that said radial surface of said annular groove includes a plurality of spaced closed cavities defined by said ribs. 8. The self-stitching fastener element defined in claim 5, characterized in that said fastener element is a male element, wherein said flange portion includes a radial head portion, and said axially projecting fastener portion is an integral stud portion. The self-locking fastener element defined in claim 8, wherein said male fastener portion is threaded on the outside adjacent said generally annular groove in said head portion, but spaced from said head portion a distance equal to approximately the thickness of a panel to which said self-healing fastener is to be attached. The self-stiffening fastener element defined in claim 5, characterized in that said fastener element is a female fastener element, wherein said fastener portion includes an integral annular gun portion with said flange portion, and said fastener includes an axial hole aligned generally coaxially with the axis of said barrel portion. The self-locking fastener element defined in claim 10, wherein said hole is threaded on the inside to receive a male fastener. An element rivetable to a piece of metal sheet, consisting of a spigot portion and an integral head portion, characterized in that said head portion of the element includes on its underside a concave contact surface having peripherally closed cavities that are partially limited by ribs extending radially outwardly from said spigot portion, the ends of said ribs extending in said spigot portion in relief at an angle along said spigot portion with radially spaced ends of the head portion, and said head portion having at least one spiral depression around said spigot portion. 13. The element defined in claim 12, characterized in that said spigot portion of said element has in the area of the ribs in relief, in comparison with the tang portion remote from the head portion, a larger diameter, containing at least one depression in said area of greater diameter. The element defined in claim 12, characterized in that said peripherally closed cavities have their maximum depth adjacent said axis portion. The element defined in claim 12, characterized in that the area of said cavities, in comparison with the contact surface of said head portion, is selected such that, based on the materials of the element and the sheet metal part , be in optimal rotating block and non-critical surface pressure. 16. The element defined in claim 12, characterized in that said cavities are delimited at their radially external termination by a peripheral surface of said head portion. The element defined in claim 12, characterized in that said rib portions in the contact area of said head portion extend radially, flared radially outward and extending without interruption to a radial peripheral surface of said contact area of said head portion. 18. The element defined in claim 12, characterized in that the number of ribs ranges between six and eight. 19. The element defined in claim 12, characterized in that said closed cavities, in plan view, are essentially quadratic. The element defined in claim 12, characterized in that the lower surface of said closed fields is generally in a conical dome surface with an inscribed angle of generally 130 to 140 °. The element defined in claim 12, characterized in that the side of the head portion remote from the contact surface includes a centering depression which is coaxial with the longitudinal axis of the element. 22. The element defined in claim 12, characterized in that said element has the form of a threaded pin, wherein said pin portion is threaded on the outside. 23. The element defined in claim 12, characterized in that a depression includes the spiral thread groove adjacent said head portion. 24. The element defined in claim 12, wherein said shaft portion has a smooth outer cylindrical surface that provides a support surface for receiving a female support member. The element according to claim 12, characterized in that said spike portion includes a centering tip having a conical end coinciding with the longitudinal axis of said axis portion. 26. The element according to claim 12, characterized in that said element is an automatic joint nut element, wherein said tang portion is generally tubular with a hole coinciding with the axis of said element extending through said element. . 27. A self-fastening member and panel assembly that includes a plastically deformable metal panel with a through hole, a fastener element that includes a radial head portion and an integral cylindrical integral fastener portion axially, including said head portion an annular support surface adjacent said fastener portion, and said support surface comprising a plurality of circumferentially spaced cavities, and said fastener portion including a radial depression spaced from said head portion, said fastener portion of the element extending through of said panel hole, and said panel deforming said cavities and said support surface of said head portion and radially said depression in said fastener portion. The element and panel assembly defined in claim 27, characterized in that said panel includes a toothed annular groove aligned coaxially with said recesses on the side of said panel opposite said head portion of the element. 29. The element and panel assembly defined in claim 28, characterized in that said indented indentation of the panel includes a corrugated bottom surface. 30. The element and panel assembly defined in claim 29, characterized in that said notched groove is interrupted. A rivet stamp for attaching a self-tapping element to a plastically deformable metal panel, wherein said member includes a radial head portion and an integral fastener portion that projects axially, said head portion including a support surface t r. next to said fastener portion with a plurality of circumferentially spaced cavities adjacent said fastener portion, said rivet die including a hole configured to receive said fastener portion of said element, and an annular riveting portion surrounding said punch hole. and protrudes from said stamp with a corrugated end face including peaks and valleys extending in the axial direction to deform the metal panel against said support surface of the element. 32. A method of forming a plastically deformable self-locking member and metal panel assembly, said self-nailing element comprising a radial flange portion and an integral fastening portion axially protruding, said head portion including an annular support surface surrounding it generally said fastener portion including a plurality of circumferentially spaced cavities adjacent said fastener portion, and said fastener portion including a radial depression spaced from said head portion, said method including the following steps: forming a hole in said metal panel configured to receive said fastener portion of said element; introducing said fastener portion of said element into said panel hole; and plastically deforming the material of said metal panel adjacent said panel hole to at least partially fill said cavities and said support surface of said head portion, and deform substantially simultaneously said panel adjacent said hole to said radial depression in said portion of fastener. 33. The method of joining an element to a panel as defined in claim 32, wherein said panel is plastically deformed by a stamp element having a hole receiving said fastener portion, and an annular riveting lip having a crown-shaped end portion including spaced apart projecting peaks separated by valleys, including method to move said riveting lip to said metal panel and simultaneously rotate said element to place said peaks in front of said cavities in said head portion.