DE2322351A1 - SELF-TAPPING THREADED FASTENING MEMBER AND PROCESS AND PAIR OF THREADED JACKS FOR THE PRODUCTION THEREOF - Google Patents

Description

Munich, May 3, 1973

My reference: P 1647
Applicant: USM Corporation

Flemington / New Jersey - USA

Delivery address: Federalstreet 14o

Boston / Mass. 02107

United States

Self-tapping threaded fastener as well Method and pair of thread rolling jaws for its manufacture

The invention relates to a self-tapping threaded fastener, that according to preferred embodiments, a zero run-in or a controlled prevailing one Bringing torque during insertion into a receiving part.

A variety of self-tapping threaded fasteners are available to disposal. Most of these fasteners fall into a group of two main groups with regard to the thread-forming effect: cutting fasteners or upset fasteners.

Although both types of fasteners are effective in forming internal threads in a female member are applicable, the compressive fastening

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limbs the more common ones. A fastener characteristic of the types of compression is shown in U.S. Patent 3,426,642. The thread-forming means provided in this type of upset screw is an elevation formation (which is designated in Figs. 1, 2 and 3 of said US patent with 21), which one almost continuous thread winding is superimposed, from the tip to the shaft.

Although the fastener described above is effective in its weak torque property exercising thread former, however, the fastening member in question suffers from the previously known method for its Mass production of adhesive properties. Currently, these fasteners are sandwiched between two thread rolling jaws rolled, each of which with a plurality of parallel, for the formation of the thread root serving elevations, thread crests forming grooves and pockets forming bulges. The rolling takes place between these jaws below Applying strong pressure, whereupon the material of the screw shaft moves (compression) with formation of the thread. In the formation of self-tapping screws with a thread forming superelevations are the grooves of the jaws which form the crests of the thread are provided with a series of pockets formed by bulges or Holes are formed. These pockets adapt to the shifting or moving plastic metal and form a composite part which is substantially superimposed on the thread. Since the parts of the Jaws or mold are actually formed by holes in the grooves forming the thread tip, the Enveloping of the superhighjrgen, of course, over the envelope of the thread in the area near the connection of the shaft

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and the tapered parts of the fastening member, i.e. in the areas in which the diameter of the tapered tapered part approximates the shaft diameter (see Fig. 3 of the above-mentioned US patent). If the fastener is made with a single thread, which has an almost uniform cross-section (a general shape), this is what causes the thread-forming elevations near the connection in question a stronger compression of the thread in the part receiving the fastening member than the actual thread on the shank part of the fastener. When the fastening member is inserted into the receiving part is, there is thus no effective torque between the upset internal thread of the receiving part and the shaft thread of the fastening member. Rather, between that Fastening member and the receiving part have a kind of loose fit. It should be easy to see that a Such a property can in certain cases be regarded as a defect which restricts the universal application of the fastening member.

This deficiency has been recognized; it is an attempt to be made been to overcome the deficiency described. In Figs. 24 to 26 of the above-mentioned U.S. patent, there is a Attempt illustrated to provide a self-tapping screw which also has a controlled effective or prevailing torque (zero gap or positive engagement between the fastener and the internal thread formed) brings with it. As shown, the known fastener includes a threaded working entry portion with a tapering thread formation, which has a smaller outer thread diameter and Pitch diameter, but has a constant core diameter. Although the fastener shown is an effective

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could bring about the same torque, since the height and Thickness of the thread-forming elevations towards the work inlet end is smaller, namely from a value that is smaller than that of the thread on the shaft part, however, the overall performance and favorable behavior of the fastener in question as a self-tapping one degrades Screw.

The effectiveness of a self-tapping screw results to a large extent from the thread formation in the work entry part. The thread formation on the screw in question must not only compress an internal thread for the approaching shaft part, but the thread in question must also lead the fastening member into the receiving part. As long as the thread does not "form" ^{cuts 11} which "cut" deep enough into the side material of the receiving part, the fastening member does not move and compress the desired thread left unthreaded or with an enlarged hole.

The invention is based on the object of showing a way of avoiding the one indicated above Difficulties a self-tapping threaded part can be formed in a particularly simple manner.

The above object is achieved by the fastening member according to the invention, which the two overcomes above problem areas by creating a fully formed thread on the work entry part is provided up to the thread part tip and that a

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Elevation structure is provided that the internal thread in compresses the receiving part with a minimum torque, and that still within the dimensional requirements with respect to of the shaft thread

As mentioned above, the two are used to form the ones described above thread rolling jaws serving conventional fasteners or -forms each provided with pockets forming superelevations. Therefore, these molds or baking be carefully placed in automatic rolling machines which will eventually be aligned in such a position that successive elevations alternate on the threads and are arranged regularly. Despite the one Care taken in such an application of the conventional roll jaws, these jaws soon lose their initial setting. In addition, during the actual rolling, e.g. during the initial introduction, the fastening

ir

link blank often on one of the conventional jaws concerned · This leads to the fact that the jaws concerned their lose the relative setting and that the correct spacing of the camber is destroyed. As expected can, irregular distances between the superelevations disrupt the thread-forming function. Put in direct contrast to this the thread rolling jaws according to the invention ensure a regular application of the elevations, regardless of ■ relative thread jaw setting or slippage of the respective fastener blank.

The present invention provides a self-tapping fastener and method of making a such fastener as well as thread rolling jaws for the Implementation of this procedure created. The fastener in question has the ability to be internally threaded

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to compress a receiving part, in such a way that, according to the preferred embodiment, the fastening member in question has a zero running torque on the introduction into the receiving part or a controlled effective torque brings with it

To this end, and in accordance with certain features of the invention, the self-tapping fastener according to FIG Invention a cylindrical shaft part and a tapered work entry part which terminates in a point. From the r The shaft part and the work entry part each have a cylindrical, helical thread carried. The continuous, helical thread on the work entry part is thread-forming Superimposed elevations, which in the preferred embodiments have a uniform size and a uniform cross-section own. The peaks in question have a cross section of the thread on which they are superimposed, similar cross-section. In the connection area of the shaft and the work entry part of the fastening member there are certain Elevations formed such that they are within the imaginary envelope of the cylindrical, helical Thread of the shaft lie, with axial projection beyond the connection in question. Achieved this is done by re-rolling for the purpose of reducing these elevations, which would otherwise envelop the shaft thread protrude.

The method of manufacturing the fastener member according to the invention comprises rolling a continuous one Thread from the shaft part to the tapering work entry part and the formation of the thread turns of the work entry part superimposed, at a distance from

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mutually provided thread-forming cusps, and a subsequent re-rolling of the threaded shaft part and bestieater Elevations on the work inlet part on the cylindrical thread of the shaft part, namely at Projection towards the top.

The thread rolling dies for rolling the fastener according to the invention include first and second thread rolling dies. These thread rolling jaws have an entry end for a fastening member and an exit end for the fastening member on. Between these ends are thread-forming surfaces with a plurality of parallel thread crests forming grooves and thread grooves forming elevations intended. Each of these thread-forming surfaces has a flat portion through which the shank of the fastener is formed which part along an edge is bounded by an upwardly sloping surface through which the tip of the Fastening member is formed. This first thread rolling jaw is the main thread rolling jaw, which one the superelevations Forming area on the surface forming the tip, in which a plurality of provided at regular intervals, superelevations forming pockets in the thread-forming grooves is included. This first thread rolling jaw also contains a post-rolling support part in which the thread-forming surface to the shank-forming flat - ' Part fits, as well as a release part. The re-rolling support part has a certain roll length, so that certain cusps of the thread-forming elevations are rolled, which otherwise over the envelope of the shaft thread turn protrude towards the tip when projected. The second thread rolling jaw has * to form a shank and a point serving part and a post-rolled part, which is placed so that certain cusps of the thread-forming

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Elevations to the envelope of the shaft thread be rolled back.

With reference to drawings, the invention is exemplified below explained.

Figure 1 shows a fastener embodying the invention. FIG. 2 shows, in a partial sectional view, the fastening element according to FIG. 1 before a re-rolling step is carried out. FIG. 2a shows an end view of the fastening member shown in FIG.

FIG. 3 shows, in a partial sectional view, the fastening element according to FIG. 2 after the re-rolling step has been carried out. FIG. 3a shows the fastening member according to FIG. 3 in an end view.

Fig. 4 shows in a perspective view thread rolling jaws for the manufacture of a fastening member according to the invention.

FIG. 5 shows the illustrated in FIG. 4 in a partial sectional view Thread rolling jaws in rolling operation. FIG. 6 shows a follow-up view of that shown in FIG Thread rolling jaws during rolling.

Fig. 7 shows the Nachwalζvorgang in a sectional view the thread rolling jaws.

FIG. 8 shows a subsequent view of another embodiment of the invention according to FIG. 6.

In the following, FIG. 1 in particular is considered in more detail. In In this figure, 10 is a self-tapping screw which represents an embodiment of the invention. The screw 10 includes a cylindrical shank portion 12 with a head 14 at one end and a pointed end Work entry part or work introduction part 16, which is formed in a tip 18 at the other end of the shaft part

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ORIGINAL

runs. The tip 18 can terminate in a sharp point or, as shown, be blunted. The head 14 is expediently provided with means such as a transverse slot 20 provided in order to provide a driving system for a tool (not shown), such as a conventional screwdriver achieve. The head 14 is not necessarily expanded.

The screw 10 has a thread 22 which begins at the tip 18 and which is a spiral thread 24 ' the work inlet part 16 running to a point and extends at least over part of the shaft 12 as a cylindrical screw thread 26. On consideration in sectional view (see Fig. 2a) the thread 2o has a ' cylindrical shape over the entire area of the shaft 12. The thread arrangements each contain a thread core r, flanks f and a point c, which is designated in connection with the thread reference number, e.g. with 22r, 24f, 26c.

The thread on the work entry part 16 (Fig. 1) contains thread-forming elevations 30, which extend from the point 24r along the flanks 24f to the tip 24c extend and appear as the thread 24 superimposed bulges. The elevations 30 have a cross section Envelope 32 (FIG. 2), which runs generally parallel to the flanks 24f and tips 24c. This is an exception however, as will be explained later, the connection area 25 between the shaft 12 and the work entry part 16. This area shows a cant peak 30c, which over the Tip 24c of the thread 24 protrudes.

The elevations 30 are preferably in the circumferential direction provided along the thread at a distance from each other

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and arranged in axial rows (see Figures 1, 2 and 3) from the tip to the work entry portion 16, but not on the shaft part 12.

The elevations 30 are also shown as structures which have the front and rear sides 30a and 30t (FIG. Z) which are gradually curved from the flanks 24f in such a way that rounded elevations are formed. It should be understood, however, that the threading ridges can take one of a wide variety of shapes in addition to those shown. However, there are three basic requirements with regard to the form. The first requirement is that the 'superelevation profile protrudes beyond the thread profile on which it is provided, namely to carry the screw in the relevant area in such a way that a reduction in the friction between the screw and the receiving part is effected when the internal thread is compressed will. The second requirement with regard to the elevation shape is that the shape in question gradually rises above the flanks 24f and the tip 24c so that the material of the receiving part is not cut into. The third requirement with regard to the superelevation structure is that successive superelevations on the work entry part or lead-in part progressively further outwards from the screw axis. > stand, with the last projection provided in the direction of the shaft lying on the work introduction part and with a projection of certain re-rolled projections lying within the imaginary projection of the cylindrical shaft thread turn towards the tip. As will be explained below, the new arrangement or structure according to the invention is made possible by the new thread rolling jaws and the method of manufacturing the self-tapping fastener.

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The self-tapping fastener shown in Figs is preferably made by rolling the shank thread, the work lead-in thread and the cusps made on a conventional cylindrical screw blank by the apparatus shown in Figs. the Thread rolling dies include a first thread rolling die 42 and a second thread rolling die 44. These thread rolling dies each have a flat shaft rolling portion 46 extending longitudinally from the fastener insertion ends and 43a to the fastener exit ends 45 and 4Se extends. The shaft rolling part 46 has leading rolling grooves 48 to form the thread crests and to form the thread root serving elevations 50. Each thread rolling jaw is also provided with a tapered rolling region 52 provided, which generally expands to the same extent as the shaft rolling part 46 and the one limit of this rolling part or area forms. The tapered rolling area also has grooves 48 and elevations 50. The first thread rolling jaw or the main thread rolling jaw 42 contains, in particular, recesses in the tapered rolling region 46 or pockets 54, which are provided in grooves 48 to form the elevations according to FIGS. 2 and 2a. The concerned Recesses are preferably arranged in rows (A, B and C according to FIGS. 4 to 6 and 8).

A screw blank 40 is inserted in a conventional manner between the thread rolling jaws 42 and 44, as shown in FIG is illustrated. In the shaft rolling area or -rollteil 46 is through the thread crest rolling grooves 48 and the Thread foot elevations 50 have a cylindrical screw thread rolled on the shaft portion 12 (as shown in Figs. 1 to 3). Preferably the same threaded parts are with

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ORIGINAL INSPECTED

the elevations 50 and grooves 48 having tapered roll areas 52 equipped or suitable for these areas. Thus, the tapered work lead-in portion 16 on the fastener is simultaneously with the rolling of the Rolled shaft. The fastening member 10 is thus given a spiral thread 24 which extends almost to the tip 18 runs. The thread rolling jaws 42 and 44 and the rolling method described so far are generally known.

The elevations 30a and 30 'can initially be formed simultaneously with the rolling of the thread 24, in that the grooves 48 forming the thread peaks are provided with pockets 54 which are complementary to the elevations 30, and in particular to the elevations 30a and 30 ^f of FIG. are shaped 2 and 2a. During the exercise of the rolling process on the screw blank 40, the metal of the blank 40 moves into the pockets 54 so that the protrusions 30a and 30 'appear on the thread 24 * they appear as the flanks 24f and the tips 24c of the relevant Thread superimposed. As mentioned above, the formation of elevations 30a and 30 · takes place initially, as shown in FIG. It should be understood that in the thread rolling arrangement described so far and the thread rolling method described so far, the recesses extend over a greater depth than corresponds to the depth of the grooves 48 which form the thread crests and in which the relevant recesses are provided. The actual result of the method described so far is that an initial elevation 30 and 30 '(Fig. 2, 2a, 5 »6 and 8) is formed on the upper sections of the work introduction part 16, this elevation radially over the envelope 27 of the cylindrical

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Screw thread 26 protrudes towards the tip when projected. By such a protrusion of the elevations 30 »over the shank thread envelope becomes the self-tapping one Fastening member the desired zero gap or the controlled running torque in connection with the internally threaded receiving part taken.

Certain peaks of the peaks 30 * (which protrude beyond the shank thread enveloping 27) are initially formed almost simultaneously with the formation of the spiral thread 27 (see FIGS. 2 and 2a). These elevations 30a comprising the elevation 30 ^f are present almost uniformly (in the preferred embodiments) from the tip 18 to the shaft. On the initial formation of the elevations, the initially rolled elevations 30 * and in particular the elevation 30 * are subsequently rolled into the elevations 30 that are finally formed (see 30 in FIGS. 3, 4 and 6). In this way, a precisely dimensioned thread upsetting surface is formed, in particular in the vicinity of the connection point 25 between the work lead-in part 16 and the shaft 12. The thread-rolling arrangement used to carry out this re-rolling or re-rolling will be discussed further below. The elevations 30 ·, which would otherwise protrude beyond the envelope of the thread located on the shaft, are thus rolled back or rolled back to the precisely desired envelope. As a result of this rolling back or re-rolling, the elevations 30 are formed in such a way that the envelope of these elevations falls within the imaginary envelope / cylindrical screw thread shaft, namely when projecting over the connection point 25 of the shaft 12 and the working insert 16 towards the tip (see Fig . 3 and 3a). Further be

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pointed out that this re-rolling or re-rolling at the same time at the tips 30c and the sides 30s of the Elevation 30 * occurs, so that the entire cross-sectional envelope the elevation 30 lies within the appropriate dimensions of the thread form 22 of the shaft. This is In the present embodiment, a screw 10 with a controlled running torque created when the fastening member or the screw 10 is inserted into the receiving part after the internal thread has been compressed.

In the embodiment according to FIGS. 1 and 3, in which all rows (A, B and C) of the elevations 30 are re-rolled or are subsequently rolled (Fig. 3), a very precise thread formation occurs at the end elevations. This works in part returns the controlled measurement that is applied during the re-rolling in the formation of these end ridges, and partly due to the lower pressing or upsetting loads associated with these peaks during re-rolling, namely since their function is now in the property of an end thread core correction of the previous during the initial Rolling of the previous superelevations of upset thread lies. The overall effect of certain superelevations of the re-rolled cant during the thread upsetting process is to compensate for the torque load acting on the thread-forming ridges. At on the superelevations balanced loads, adverse stresses in the screw are avoided if this one Makes upsetting of the internal thread. This in turn leads to a considerable increase in the tightening / overturning ratio. Fasteners made by conventional methods show a relationship in this regard from about 3 to 1, while the fastening members according to FIG

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Invention have a ratio of up to 10 to 1.

Another significant advantage in terms of threading properties is achieved by a screw made in the manner indicated above. Is is known that a variety of materials, in which these self-tapping screws are inserted, so to speak, have ^N storage capacity. ¹¹ This means that the material has a certain elasticity and that the internal thread shows a slight tendency to return to its original or "filled" shape upon upsetting or deformation by the fastening member towards the exact shape of the shaft thread. There is thus some engagement between the upset internal thread and the shaft thread 26 when the screw is inserted into a threaded hole. This intervention ensures a "zero gap" and, moreover, an inhibiting function is actually achieved. The degree of inhibition or the degree of engagement can be controlled directly by the degree of unwinding which is carried out on the respective superelevation row in the re-rolling area 60 of the thread rolling jaw 44. The more the tip 30c and the side 30s are unrolled or rolled off, the smaller the internal thread will be and the stronger the engagement torque or the prevailing or effective torque on the screw will be.

The thread rolling jaws 42 and 44 used to provide the above-described new fastener according to the invention are suitable, have a re-rolling or dimensioning area in which the thread-forming surface 62 according to the desired final shape and size of the elevations 30 is formed. In a corresponding manner, the thread rolling jaw 42 has a Rerolling support area 61 with a thread-forming surface 63.

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In the illustrated embodiments, these are thread-forming Areas provided with burr-like elevations 50 and grooves 48, which are comparable to the elevations and Grooves in the part 46 forming the shaft thread in which the cylindrical screw thread is rolled. This re-rolling or Nachrollteile 60 and 61 are on the thread rolling jaws 42 and 44 in connection with the shaft rolling parts or areas 46 and the tapered rolling areas 52 are provided. In the preferred embodiment, the post-roll areas are 60 and 61 only by a short extra area in the roll jaws 42 and 44 next to the exit ends 45 and 45a educated. The length of the respective areas in the rolling direction is approximately equal to the circumference of the fastening member 10. This ensures re-rolling or re-rolling over the entire circumference of the fastening member 10 and thus all of it Superelevation series (especially the 30 'superelevation of rows A, B and C, which are otherwise over the envelope 27 of the shaft thread protrude when projecting towards the tip).

According to one embodiment of the thread rolling jaws, the rolling support area 61 of the thread rolling jaw 44 can have a rolling length which is substantially shorter than the length of the circumference of the fastening member. In such embodiments, re-rolling or re-rolling can be effected not all, but only a few elevations 30 ^f . 8, the protrusions 30 * formed by the recesses 54 of rows A and B are rolled back to the specific shape (cylindrical shaft thread), and the protrusions 30 of row C remain in the individually rolled shape. This is due to the fact that the thread-forming surface 62 in this embodiment has such a limited length that

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that they do not have the fastener over the first two Third of the re-rolling carries and acts on this. Of course, the first thread rolling jaw 42 carries the Screw during this re-rolling, and the extent of the re-rolling can also be determined by the length of the support area being controlled.

The product of the above-described thread rolling jaws according to the second embodiment is a self-tapping screw with thread-forming elevations 30, which are all of the same size in the tip area 18 of the work introduction part 16. In the area approaching the shaft connection point 25, however, there is a superelevation row (this is the superelevation row C in the drawing) is "oversize". This means that projections radially over the thread 26 of the shaft 12 survive. This allows the elevations 30 of rows A and B to precisely match the internal thread of the receiving part cylindrical screw threads 26 press or compress, while the oversized elevations 30 'of the row C for compression a larger internal thread. This screw shows many of the demands on the delivery of one reduced thread torque according to the first embodiment, and further such a compression of an internal thread takes place in the receiving part that essentially a zero running torque or a very weak effective torque is achieved between the receiving part and the shaft thread 24. It also has very precise and even tolerances Achieved screw-to-screw manufacturing.

In practice, the cant is usually done both thread rolling jaws rolled. This requires precise alignment procedures when the roller jaws are in the Rolling machine are used. When a screw blank on

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one of the roll jaws during the initial roll states little slippage is, as already mentioned above, the circumferential alignment affected by the cant. In the conventional execution technique, a complete Series of peaks due to alignment or slip problems completely eroded or removed from a screw unrolled (or significantly deformed).

In contrast to the previously considered practice, the recesses 54 forming the elevations are according to the invention provided in one of the thread-forming roll jaws (see Fig. 4). Because all of the cantilevers Forming recesses 54 in a thread rolling jaw, such as the thread rolling jaw 42, are accommodated, a Proper arrangement of the superelevations can be guaranteed, which leads to the precise rolling of the thread-forming superelevations 30 contributes.

The present arrangement of the recesses 54 forming the elevations and the roller jaw arrangement leads to the formation a fastener with cant, necessarily are arranged correctly and which are not subsequently removed or unrolled in a non-controlled manner. All of the peaks 30 are applied to the thread 24 by a single roll jaw, the relative setting or change of the co-operating with this roll jaw no effect on the placement of the Has cant.

The present invention, as should now be seen, self-tapping screws with a

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Variety of s & ied running torques in masses and can be produced with a uniformity not previously known in the industry. Although in the present If preferred embodiments of the invention have been described, it should be understood that without departure A large number of changes and modifications are still possible from the concept of the invention.

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Claims (1)

Claims Self-tapping threaded fastener having a cylindrical shank portion with a head at one end and at the other end of which a tapered work introduction part is provided, which ends in a point, wherein the shaft part and the work introduction part each have a continuous screw thread with a thread core part, and Have flanks and a thread tip part / wherein the thread in question runs from the tip of the work lead-in part to the shaft part in the direction of the head, and with a multiplicity of thread-forming cusps which are superimposed on the thread in the work lead-in part of the shank part, characterized in that the cusps ( 30) have outwardly over the flanks (24f) of the thread (24) selectively protruding flanks (30) and selectively over the thread tip (24c) of the thread (24) protruding tips (30) that the elevations (30) of the same size are. and define an envelope which is symmetrical in cross section with respect to the thread (24) from the tip (18) to the shaft part (12) to near a connection point (25) between the shaft part (12) and the work introduction part (16. ) and that successive envelopes of the elevations (30) decrease in size symmetrically with respect to their tips (30c) and flanks (30s) in such a way ehmen that they are limited by an imaginary envelope of the cylindrical screw thread (26) on the shaft part (12) when projected in the axial direction beyond the connection point (25) to the said tip (18). 2. Fastening member according to claim 1, characterized in that a plurality of the thread-forming elevations (30) in 309849/0838 -ZI- a plurality of rows (30A, B, C) is arranged and that these rows are uniform in the scope of the work introduction part (16) are arranged around. 3 * fastening link according to claim 2, characterized in that that the rows (30A, B, C) of elevations (30) each generally axially on the work introduction part (16) are arranged 4. Fastening member according to claim 3, characterized in that the elevations (30) of all rows (3OA, B, C) to run in the vicinity of the junction (25) of the shaft part (12) and the work introduction part (16) and follow one another decrease in size symmetrically to their tips (30c) and flanks (30s), so that they through the imaginary envelope of the cylindrical screw thread (22) of the shaft part (12) when projected in the axial direction are limited beyond the connection point (25) to the tip (18). 5. Fastening member according to claim 1, characterized in that at least one of the rows (3OA, B, C) elevations (30) of almost the same size and shape from the tip to the said junction (25) between the shaft part and the work lead-in part (16), these Elevations (30) in the vicinity of the connection point (25) on the work introduction part (16) radially over the said Envelope of the shaft thread (26) when projecting beyond the named connection point (25) to the tip (18) survive. 309849/0838 6. A method for producing a self-tapping threaded fastener, in particular according to one of claims 1 to 5, with a nearly cylindrical shaft, a head at one end and a tapered working lead-in part which terminates in a point at the other end, and with a A multiplicity of elevations which are superimposed on a thread located on the work introduction part, characterized in that first a continuous cylindrical screw thread (22) with a core part (22>), flanks (22f) and a pointed part (22c) on the shaft part (12 ) and the working lead-in portion (16) of a fastener blank (40) is rolled while a plurality of elevations (30a, ^30f ) are formed, which the flanks (24f) and the pointed parts (24c) of the thread (24) certain points of the work lead-in part (16) are superimposed, these elevations defining an envelope, the cross-section of which is almost symmetrical to d em thread (24) runs, and that then the thread-having shaft part (12) and the thread-having work lead-in part (16) are rolled in such a way that certain elevations (30) on the work lead-in part (16) next to the connection point (25) Elevations (30) formed between the relevant work introduction part (16) and the shaft part (12) are reduced to such a size that they lie within a thread envelope, which is determined by the imaginary projection of the threads of the shaft part (12) over said connection point (25) is formed out towards said tip (18). 309849/0838 7. The method according to claim 6, characterized in that the peaks (30, 30 ·) by rolling in a variety of rows (3OA, B, C) are formed, which in almost, equal distances around the circumference of the work introduction part (16) can be arranged around 8. The method according to claim 6 or 7 »characterized in that that a certain number of the above-mentioned series of elevations (30a, 30 ») is subjected to a re-rolling process, where the number in question is smaller than the total number of rows 9 · Pair of thread rolling jaws for producing a self-tapping threaded fastening element, in particular according to one of the Claims 1 to 5, characterized in that a first thread rolling jaw (42) is provided which has a fastening member insertion end (43), a fastener output end (45) and a shaft rolling portion (46) having a row of almost parallel, a thread core part forming elevations (50) and a thread tip part forming grooves (48) extending at angles corresponding to the thread angle of a fastener member blank (40) correspond to the thread to be formed that the first thread rolling jaw (42) has an inclined rolling area (52) having, in the rolling sequence following the shaft rolling region (46), grooves (46) forming a thread tip part and a thread core part forming elevations (50), said grooves (6 $) in the latter Rolling area (52) are provided with pockets (54) that form cusps at certain points * which are generally close to the The output end (45) lies so that the first thread rolling jaw (42) has a re-rolling support area (42) behind the shaft rolling area (46) and the inclined rolling portion (52) that the 309849/0 838 Nachrolltragbereich (62) a thread core part forming elevations (50) and a thread tip part forming Grooves (48) in continuation of the elevations and grooves of the shaft rolling area (46) and the inclined rolling area (52) and is arranged almost in the same plane as the shaft rolling area (46) that one with the first thread rolling jaw (42) cooperating second thread rolling jaw (44) having a fastener entry end (43a) and a Fastening link exit end (45a) is provided that this second thread rolling jaw (44) has a shaft rolling area (46) with a series of almost parallel, a thread core part forming elevations (50) and a thread tip part forming grooves (48), which at angles extend which correspond to the thread angle of the thread to be formed in the fastener blank (40), that in the longitudinal direction of the shaft rolling region (46) an inclined rolling region (52) with elevations forming a thread core part (50) and grooves (48) forming a thread tip part and a post-rolling area (60) are provided, which is generally provided near the outlet end (45a) and which is in the rolling sequence at the shaft rolling area (46) and the inclined rolling area (52) adjoins that the Nachrollbereich (60) has elevations (50) and grooves (48), the continuations of the elevations (50) and grooves (48) of the shaft rolling area (46) and the inclined rolling area (52) and which are almost in the same plane as the shaft rolling area (48), and that the Nachrolltragbereich (61) and the Nachrollbereich (62) are arranged such that they during the rolling sequence are generally opposite one another in such a way that the surfaces of the shaft previously rolled through the shaft rolling area (46) and the inclined rolling area (52) rolled fastening member on the thread shape of the Nachrollbereich (60) can be rolled. 3Q9849 / Q838 # Pair of thread rolling jaws according to claim 9 »characterized in that that the longitudinal dimension of the Nachrollbereiches (60) of the contested thread rolling jaw (44) at least equal to the circumference is a fastening member rolled on the thread rolling jaw in question. 11. Pair of thread rolling jaws according to claim 10, characterized in that that the longitudinal dimension of the NachroÜtragbereiches said first thread rolling jaw (42) is at least equal to the circumference of a fastening member rolled on said thread rolling jaw. 12. Pair of thread rolling jaws according to claim 9, characterized in that that the longitudinal dimension of the Nachrollbereiches (60) of the second thread rolling jaw (44) is at least equal to half of the circumference is a fastener member rolled on this thread rolling jaw. · 13. Pair of thread rolling jaws according to claim 12, characterized in that that the longitudinal dimension of the Nachrollbereiches (60) is at least equal to half of the circumference of one on this Thread rolling jaw is rolled fastener. 309849/0838