Fastener

Abstract

The invention relates to a fastener having a shaft, a head integrally formed thereon at one end of the shaft, a tip at the end of the shaft opposite the head, and an anchoring portion which is structured in the manner of a thread and comprises a first thread turn having a rounded flank crest portion and a second thread turn having a flank crest which is pointed relative to the rounded flank crest portion, the width of the flank crest portion of the first thread turn being greater than the maximum width of the second thread turn, in particular the width of the flank crest portion of the first thread turn corresponding to a multiple of the maximum width of the second thread turn.

Description

[0001] Fasteners

[0002] The invention relates to a fastener comprising a shaft, a head formed on it at one end, a point at the end of the shaft opposite the head, and an anchoring section structured in the manner of a thread.

[0003] These fasteners are typically screw fasteners. The thread in the anchoring section is designed to engage with the substrate when turned, allowing the fastener to secure an object to the substrate. Screw fasteners have a head with a drive surface. This can be an external drive surface or an internally embossed drive surface, such as a cross-recess. Screw fasteners are screwed into the substrate manually or with a power tool. The screwing process, especially when done manually, takes time. A key advantage of screw connections is that they can generally be loosened again.

[0004] Fasteners of the type mentioned above can also be designed as screw nails. These hammer-in fasteners have a nail point to which the anchoring section, with its threaded structure, is attached. The thread in the anchoring section is typically a cord thread. The thread pitch, typically more than 50°, is several times greater than that of a conventional screw thread. This pitch is measured along the radial axis of the anchoring section. This is necessary so that when such a screw nail is driven in with one or more hammer blows, the screw shank is screwed into the substrate. These types of fasteners are primarily used with hardwoods as a base for fastening wood panels or particleboard.The primary purpose of screw nails is to prevent the wood from splitting. However, a disadvantage of this fastener is that they are either impossible or extremely difficult to remove. Therefore, screw nails are mainly used when the connection needs to be permanent.

[0005] Sometimes it is necessary to anchor a fastener at an angle to the surface of the mounting surface or to insert a mounting element at an angle. In facade construction, there are applications where a screw fastener is to be inserted into the anchoring opening of a mounting bracket with its anchoring section. The longitudinal axis of the screw fastener's shank is oriented perpendicular to the surface of the mounting element supporting the anchoring opening and must be brought into the opening in this position. Typical angles of the fastener's shank relative to the surface of the mounting element containing the opening range from 20° to 50°. The same applies to applications where a mounting element is to be inserted at an angle by such a fastener to anchor it in a mounting surface behind it, for example, a wooden beam.With such anchoring systems in facade construction, it is necessary to insert the fastener blindly into the anchoring opening or the access opening of the mounting element, since the mounting element is located behind the exterior of the facade or a facade component and is therefore not visible to the installer. Setting gauges are sometimes used to aid in the accuracy of positioning such an opening in the mounting element. However, this does not eliminate the problem discussed below. The problem with such a fastening arrangement is that, due to the angled contact of the anchoring section with its thread on the surface of the metal mounting element, the screw thread intended for anchoring is significantly reduced in height (at least one thread turn) as a result of the rotation of the anchoring section relative to the surface of the mounting element.Proper anchoring of this screw fastener with the intended pull-out forces is then no longer guaranteed.

[0006] This is problematic because, when screwing in such a fastener, an installer cannot see to what extent the screw thread has been reduced in height in relation to locating the opening of the mounting element. A subsequent check is not possible.

[0007] When higher pull-out values ​​are required for a nail used as a hammer-in fastener, so-called grooved or anchor nails are used. These nails have an anchoring section extending from the tip with radially projecting, ring-shaped anchoring structures that, unlike a screw nail, do not thread around the shank. These anchoring structures are asymmetrical in a side view. The flank facing the tip is inclined relative to the longitudinal axis of the shank, for example, at an angle of 35° to 40°. The side facing the head runs perpendicular to the longitudinal axis of the shank. When the anchoring section is driven into a typically soft substrate, the anchoring structures act like abutments, which in turn explains the higher pull-out forces compared to nails with an unstructured surface.These types of drive-in fasteners are only suitable for substrates that are not prone to splintering, such as softwoods. These drive-in fasteners are also neither intended nor suitable for detachable connections.

[0008] Based on this discussed state of the art, the invention therefore aims to further develop a fastener of the aforementioned type in such a way that it is characterized above all by particularly universal application possibilities and is thus suitable for blind mounting, in particular blind angled mounting, as mentioned above with reference to a facade fastening, as well as for the production of a releasable drive-in fastening, ultimately at least largely independent of the material properties of the fastening substrate.

[0009] This problem is solved according to the invention by a fastener of the type mentioned at the outset, in which the thread-like structuring of the anchoring section comprises a first thread with a rounded flank apex section and a second thread with a contrasting pointed flank apex, wherein the width of the flank apex section of the first thread is greater than the maximum width of the second thread, in particular a multiple thereof.

[0010] This fastener is distinguished by the unique design of its anchoring section. This section features two differently shaped threads. The first thread has a rounded apex, while the second thread has a more pointed apex. The two threads have different widths along the longitudinal axis of the fastener's shank. The convexly rounded apex of the first thread is significantly wider than the maximum width of the second thread. The apex of the second thread is formed by the thread's flanks, which are inclined relative to each other and converge radially. The maximum width of this thread is the width typically found at its root, where it meets the core.Typically, the width of the flank apex section of the first thread segment is several times the maximum width of the second thread, for example, two to three times. Thus, the first thread segment, with its convexly curved flank apex section, occupies a significantly larger proportion of the anchoring section's longitudinal extent than the second thread segment.

[0011] The design of an anchoring section in this structure, unusual in light of the prior art, where the pitch of the threads is typically less than 25°, particularly less than 20°, and preferably between 15° and 18°, enables the fastener to be anchored in virtually any substrate into which a screw fastener or nail can be inserted. This fastener can also be designed in different ways, both as a screw fastener and as a drive-in fastener. If the fastener is designed as a screw fastener, its head has a rotational engagement contour, typically an embossed rotational engagement contour on the top of the head, allowing it to be designed as a countersunk head.With such a screw fastener, there is no risk that, during angled mounting, particularly blind angled mounting in connection with locating the anchoring or through-hole of a mounting element, the thread required for effective anchoring of the fastener will wear down or be eroded by friction against the surface of the mounting element. Since, according to a preferred embodiment, the diameter of the two threads is the same, the first thread, which is supported on the surface of the mounting element by its flank apex section, protects the second thread from wear and the associated reduction in diameter.Since the second thread remains intact in its sections between adjacent thread sections of the first thread, despite rotation on the surface of the mounting element to locate the opening, the second thread can also be used as the drive contour (drive thread) for screwing the fastener into a fixing base located behind the opening of the mounting element, for example, a wooden beam. In such a case, the opening of the mounting element does not need to be designed as an anchoring hole into which the anchoring section of the fastener is screwed, but rather its diameter is larger than the outer diameter of the anchoring section. With such a design of the fastener as a screw fastener, the second thread preferably extends to the tip.Therefore, such a fastener is designed with regard to the equipment of the tip in the same way as screw fasteners are generally known to be.

[0012] A further advantage of this fastener is that, due to the special design of its anchoring section, it can be driven into virtually any substrate, and even with brittle materials, splintering or breakage is not a concern. The exceptional pull-out forces that this fastener withstands in such a substrate are also due to the radial support provided by the first thread, similar to a tight fit.A further advantage is that, viewed longitudinally, a relatively small gap is created between the first and second threads of the anchoring section. This gap serves as a clamping space for material from the substrate, into which, depending on the substrate material, it deforms after prior elastic expansion. If elastic expansion is not possible due to material properties, material abrasion can accumulate in this space. Therefore, a shank fit is provided, ensuring that the tensile stress on this fastener is not only transferred to the material of the substrate (e.g., aerated concrete blocks) located between the two thread sections, but also secures it with a radial compression fit within the substrate.

[0013] This fastener, especially when equipped with a nail point, can be used as a drive-in fastener. If the head of this fastener has a drive contour for engaging a tool, the fastening arrangement created with such a fastener can also be undone due to the threaded structure of its anchoring section. When such a fastener is used as a drive-in fastener, the threads in its anchoring section do not serve the purpose of rotating the fastener when driven in by a hammer blow. Rather, when driven in, the fastening base is widened by the point and subsequently by driving in the anchoring section, with the thread gaps, which extend helically around the core, being used to receive material from the fastening base.This ensures that, even with a more brittle substrate such as aerated concrete blocks or gypsum plasterboard, the internal cohesion of the substrate is maintained in the immediate vicinity of the drive hole, preventing it from cracking. Regardless of the intended use of such a fastener, the anchoring section always maintains the same basic structure. Since such a fastener is typically equipped with a head featuring an integrated drive contour, the different designs of the fastener differ solely in the shape of the tip, which can be a nail point or a screw point. It is also possible to design the tip of such a fastener as a drill point.

[0014] To limit the gaps between threads and to provide a sufficient width for the apex section of the first thread, the apex section is curved with a constant radius according to a preferred embodiment. This is preferably done extending from its apex over at least 15° and no more than 45° in each direction. A particularly preferred extension of the apex section over 20° to 25°, again extending from the apex in both directions, is also preferred.

[0015] Preferably, the flank apex section transitions into a section curved in the opposite direction towards the adjacent thread section of the second thread. The second thread section is typically positioned centrally between the flank apex sections of adjacent thread sections.

[0016] To enable the second thread to be used as a drive contour in both directions, in an advantageous embodiment the second thread is designed symmetrically with respect to the radially converging inclination of its flanks. The fastener according to the invention can have an unstructured shank section between the anchoring section and its head. This section is unthreaded. It is also possible to provide an unthreaded shank section adjacent to the anchoring section, followed by a threaded section extending towards the head of the fastener. This threaded section can extend to the head. Alternatively, a further unstructured shank section can be provided between this threaded section and the head.Such fasteners are particularly suitable for positioning, for example, the reveal of a window or door opening to a mounting surface enclosing the window or door opening, such as one provided by masonry.

[0017] The invention is described below with reference to exemplary embodiments and the accompanying figures. These show:

[0018] Fig. 1: A side view of a fastener according to a first embodiment of the invention,

[0019] Fig. 2: an enlarged view of the pointed end

[0020] End area of ​​the fastener of Fig. 1 and

[0021] Fig. 3: an enlarged view of the pointed end

[0022] End region of another fastener according to the invention.

[0023] A fastener 1 comprises a shaft 2, at one end of which a head 3 is integrally formed. The head 3 has a rotational engagement contour 4 (shown with dashed lines) incorporated into it. The head 3 is designed as a countersunk head and has several friction ribs 5 arranged at equal angular intervals on its underside facing the shaft 2 to form a hole opening for the countersunk head. In the illustrated embodiment, the shaft 2 is divided into an anchoring section 6, an unstructured section 7 arranged between this and the head 3, and a tip 8.

[0024] The anchoring section 6 is structured by two threads 9 and 10. The first thread 9 has a width that is several times greater than the width of the second thread 10. The width of a thread is its extent in the direction of the longitudinal axis L of the shaft 2. The first thread 9 is characterized by a convexly rounded flank apex section 11 (see Fig. 2). In the flank apex section 11, the thread is curved with a constant radius and, in the illustrated embodiment, extends from the apex by approximately 22° in each direction, i.e., towards the tip 8 and towards the head 3. Due to this contouring, the first thread 9 has a convex appearance. The width of the flank apex section 11 in the illustrated embodiment is slightly more than twice the maximum width of the second thread 10.The second thread 10 is formed by two flanks 12, 12.1 inclined radially towards each other. The angle enclosed by the flanks 12, 12.1 is approximately 40° in the illustrated embodiment. Both flanks 12, 12.1 are symmetrical to each other and are therefore inclined at the same angle to the longitudinal axis L. The transition from the flank apex section 11 of the first thread 9 to the second thread 10 is provided by a section 13 curved in the opposite direction to the curvature of the flank apex section 11. Due to the aforementioned design of the second thread 10, it has its maximum width at the transitions to the sections 13 arranged on both sides. The outer diameter of the shank 2 is determined by the two threads 9, 10. Both threads 9, 10 have the same outer diameter at their respective apex.Thus, the apexes of the two threads 9, 10 were aligned on a virtual cylindrical surface in the direction of the longitudinal extent of the anchoring section 6.

[0025] In the embodiment shown in Figures 1 and 2, the second thread, with its apex pointed by the radially converging flanks 12, 12.1, extends into the tip 8. The tip 8 of the embodiment of the fastener 1 is thus designed like the tip of a conventional screw fastener.

[0026] The pitch of the threads 9, 10 is shown in Fig. 2, measured relative to the longitudinal axis L of the shaft 2 by the angle α. In the illustrated embodiment, the pitch is approximately 17°.

[0027] The fastener 1 shown in Figs. 1 and 2 has a nominal diameter of 6 mm, measured in its unstructured section 7. The outer diameter of the anchoring section 6 with its threads 9, 10 of equal diameter has an outer diameter of 7.8 mm.

[0028] The fastener 1 is designed as a screw fastener and is therefore particularly suitable for applications where an object is to be fastened at an angle, especially in a blind angled mounting, either to the mounting element itself or to a mounting base located on the back of the mounting element. When the fastener 1 is typically rotated with a power tool and the through-hole in the mounting element is located, the second thread 10 remains undamaged, at least as far as it is located between two adjacent thread sections of the first thread 9, despite rotating contact with the surface of the mounting element.Therefore, when screwing the anchoring section 6 of the fastener 1 into a mounting base located behind such a mounting element, for example a wooden beam, the drive contour provided by the second thread 10 is maintained. This also ensures that the anchoring section 6, and thus the fastener 1, inserted into a mounting base, withstands the pull-out forces intended for the fastener 1. It is irrelevant if the section of the second thread 10 extending towards the tip 8 is slightly reduced in height or completely worn away during the process of creating a through-hole for the mounting element. Due to the aforementioned design of the anchoring section 6 with its two differently shaped threads 9, 10, the flank apex section 11 of the first thread 9 also works together with the second thread 10 to inhibit pull-out.The former acts as a fit in the mounting base. At the same time, this thread 9 ensures that the free space between the two threads 9, 10 arranged in the longitudinal extension of the anchoring section 6 is relatively small, and that material abrasion of the mounting base in this space simultaneously transforms the anchoring section into a shaft fit with a corresponding frictional engagement acting in the radial direction.

[0029] When the fastener 1 is screwed into a borehole lined with a dowel, the first thread 9 ensures the radial expansion of the dowel and a special press fit.

[0030] Although the fastener 1 is described above as a screw fastener, it can also be used as a drive-in fastener. The anchoring of the anchoring section 6 in a fixing base is significantly improved compared to conventional fasteners and, in particular, unlike conventional screw nails or anchor nails, can also be loosened again due to the rotating drive contour 4 incorporated into its head 3. In such a case, the second thread 10 serves as the drive contour for unscrewing the fastener 1.

[0031] The end section of another fastener 1.1 shown in Fig. 3 is designed as a nail point with respect to its tip 8.1. The screw fastener 1.1 corresponds to the screw fastener 1, except for the design of its tip 8.1. Identical features are therefore indicated by the same reference numerals, supplemented by the suffix ".1". Thus, unless otherwise stated below, the preceding descriptions for fastener 1 also apply to fastener 1.1.

[0032] This fastener 1.1 is designed as a drive-in fastener (nail) based on the design of its tip 8.1. Due to the special design of its anchoring section 6.1, it can be driven into a wide variety of materials as a drive-in fastener without the risk of internal damage, even in brittle substrates. When the fastener 1.1 is driven in – the same applies to fastener 1 – the threads 9.1, 10.1 do not cause the fastener 1.1 to rotate. The space between the threads 9.1, 10.1 serves to receive material from the substrate, which can be pushed into this space. The head of the fastener 1.1, not shown in the figures, is also equipped with a drive contour, so that this fastener 1.1 can also be unscrewed from the substrate to release the connection it has created.

[0033] The invention has been described with reference to exemplary embodiments. Without departing from the scope of protection described by the applicable claims, numerous further embodiments of the inventive concept would be apparent to a person skilled in the art, without these needing to be explained in more detail within the scope of these explanations.

[0034] Reference symbol list

[0035] 1, 1.1 Fastener 2 Shaft

[0036] 3 heads

[0037] 4 Rotary drive contour

[0038] 5 friction ribs

[0039] 6, 6.1 Anchorage section 7 Section

[0040] 8, 8.1 Peak

[0041] 9, 9.1 first thread

[0042] 10, 10.1 second thread

[0043] 11 Flank vertex section 12, 12.1 Flank

[0044] Section 13

[0045] L Longitudinal axis a slope

Claims

REQUIREMENTS 1. Fastener with a shaft (2), with a head (3) integrally formed thereon at one end, with a point at the end of the shaft (2) opposite the head (3) and with an anchoring section (6, 6.1) structured in the manner of a thread, comprising a first thread (9, 9.1) with a rounded flank apex section (11 ) and comprising a second thread (10, 10.1 ) with a flank apex in contrast, wherein the width of the flank apex section (11 ) of the first thread (9, 9.1 ) is greater than the maximum width of the second thread (10, 10.1 ), in particular a multiple thereof.

2. Fastener according to claim 1, characterized in that the radius of curvature of the flank apex section (11) is designed with a constant radius, starting from the apex, extending over at least 15° and typically not more than 45°, in particular over 20° to 25° in both directions.

3. Fastener according to claim 1 or 2, characterized in that the curved flank apex section (11 ) transitions into a section (13) curved in the opposite direction.

4. Fastener according to claim 3, characterized in that the second thread section (10, 10.1 ) is arranged centrally between the flank apex sections (11 ) of adjacent thread sections.

5. Fastener according to one of claims 1 to 4, characterized in that the outer diameter of the anchoring section (6, 6.1 ) is the same with respect to its two threads (9, 10; 9.1 , 10.1 ).

6. Fastener according to one of claims 1 to 5, characterized in that the threads (9, 10; 9.1 , 10.1 ) in the anchoring section (6, 6.1) have a pitch of less than 20°, in particular between 15° and 18°.

7. Fastener according to one of claims 1 to 6, characterized in that the flank apex of the second thread (10, 10.1 ) is formed by the flanks (12, 12.1 ) of this thread (10, 10.1 ) which converge in a radial direction.

8. Fastener according to claim 7, characterized in that the width of the second thread (10, 10.1 ) decreases linearly in the direction towards the flank apex.

9. Fastener according to one of claims 1 to 8, characterized in that the second thread (10, 10.1 ) is symmetrical with respect to the inclination of its flanks (12, 12.1 ).

10. Fastener according to one of claims 1 to 9, characterized in that the width of the flank apex section (11 ) of the first thread (9, 9.1 ) corresponds to 2 to 3 times the maximum width of the second thread (10, 10.1 ).

11. Fastener according to one of claims 1 to 10, characterized in that the head (3) formed on the shaft (2) extends beyond the maximum diameter of the shaft (2) in a radial direction.

12. Fastener according to one of claims 1 to 11, characterized in that the head (3) formed on the shaft (2) is equipped with a rotational engagement contour (4) for attaching a screwdriving tool.

13. Fastener according to any one of claims 1 to 12, characterized in that the tip (8.1) of the fastener (1.1) is designed as a nail tip.

14. Fastener according to any one of claims 1 to 12, characterized in that the second thread (10) extends into the tip (8) of the fastener (1).

15. Fastener according to one of claims 1 to 14, characterized in that an unstructured section (7) of the shaft (2) is arranged between the anchoring section (6, 6.1 ) and the head (3).

Images