Individually threaded helices secured by claws

Abstract

The invention relates to a screw comprising a shank (10); at least one thread (30) arranged on the shank, surrounding the shank and protruding from the shank; and a separate helical element (37) arranged non-integrally on the shank, wherein the separate helical element surrounds the shank, protrudes from the shank and constitutes at least a part of the at least one thread. According to the invention, the screw further comprises at least one first claw (51) protruding from the shank and having a radial and axial overlap with the separate helical element, wherein the shank and the at least one first claw are integral with respect to each other.

Description

Technical Field

[0001] The invention relates to a screw according to the preamble of claim 1. A screw of this type comprises a shank having a distal end, a rear end located opposite the distal end and a longitudinal axis extending through the rear end and through the distal end, at least one thread arranged on the shank, surrounding the shank and protruding from the shank, and a separate screw element arranged non-integrally on the shank, wherein the separate screw element surrounds the shank, protrudes from the shank and constitutes at least a part of the at least one thread. Background Art

[0002] US2010247267 A1 discloses a concrete screw, ie a screw that can be tapped and screwed into a drilled hole in a concrete substrate. The screw of US2010247267 A1 is completely integral.

[0003] US2018283435 A1 discloses a concrete screw having a separate screw element separated from a shank. The separate screw element is located in a receiving groove provided in the shank. The receiving groove has an inclined wedge-shaped side facing backward. The receiving groove also has an inclined forward-facing side, but the forward-facing side is relatively steep compared to the rearward-facing side.

[0004] US2010290858 A1 (EP2185829 B1) discloses a screw comprising a handle element and a separate spiral element attached thereto. According to US2010290858 A1, the separate spiral element or the handle element may be provided with recesses arranged at regular distances, respectively, wherein the corresponding other element (i.e., the handle element or the separate spiral element, respectively) is provided with a matching protrusion that can engage with the recess. In addition, the separate spiral element may be welded or bonded to the periphery of the handle.

[0005] US2020063231 A1 describes a martensitic hardenable steel and its use in concrete screws.

[0006] DE8713708 U1 describes a threaded connection consisting of two elements, each element comprising a helical thread groove; these elements are connected by a separate screw element, providing a secure locking.

[0007] DE 10 2015 214 257 A1 describes a shank-hub connection in which the shank has an external toothing and the coaxially arranged hub has a corresponding internal toothing.

[0008] US2011142569 A1 discloses a concrete screw, wherein most of the threads are integral with the shank except for the area closest to the end which is a separate part. The material of the separate part is selected for tapping concrete.

[0009] EP 3 620 673 A1 and EP 3 620 672 A1 disclose further concrete screws with a separate threaded portion, which are intended to drive into concrete, wherein the rear part of the respective thread may again be integral with the shank.

[0010] Another screw with a separate screw element is described in European patent application No. 20158000.8. This application proposes using a stainless steel of a specific hardness value for the separate screw element and the shank.

[0011] European patent application No. 19172762.7 also relates to a concrete screw with a separate screw element. In this case, it is proposed to provide the separate screw element with grooves, which are intended to promote radial expansion. Summary of the invention

[0012] It is an object of the invention to provide a screw which has particularly good properties, is particularly easy to produce and / or is particularly strong.

[0013] This object is achieved by a screw according to claim 1. The dependent claims relate to preferred embodiments of the invention.

[0014] The screw of the invention comprises at least one first jaw which projects from the shank and has a radial and axial overlap with the separate screw element, in particular for fixing the separate screw element on the shank, wherein the shank and the at least one first jaw are integral with respect to each other.

[0015] In conjunction with the present invention, it has been found that when the concrete self-drilling screw is provided with a separate spiral element, the interface between the separate spiral element and the shank must withstand significant forces. When the installed screw is loaded, the interface must transmit tensile forces in the direction of the longitudinal axis of the shank, etc. In addition, the interface must also withstand forces generated during the installation of the screw. These forces may have circumferential components that tend to radially bend the separate spiral element or / and to unwind the separate spiral element from the shank. Therefore, a strong connection needs to be established between the separate spiral and the shank element, which can complicate and / or costly manufacture.

[0016] In view of this, it is suggested to provide at least one first claw for the screw, which overlaps with the individual spiral element both radially (i.e. perpendicular to the longitudinal axis) and axially (i.e. parallel to the longitudinal axis). Due to the axial overlap, there is an axial portion occupied by the first claw and the individual spiral element, and in this axial portion, the individual spiral element is clamped between the first claw and the shank. Therefore, the first claw provides a stable locking mechanism, which radially fixes the individual spiral element on the shank. In addition, the mechanism can ensure the frictional contact between the side surface of the individual spiral element and the shank, or if provided, it can ensure the meshing of the corresponding teeth on the individual spiral element and the shank, respectively, wherein both of these systems allow the transmission of circumferential force between the shank and the individual spiral element. In addition, the radial overlap between the first claw and the individual spiral element can provide a stable locking mechanism, which can also axially fix the individual spiral element on the shank. Therefore, axial, radial and / or circumferential forces can be particularly effectively transmitted between the shank and the individual spiral element, which can provide particularly good screw performance.

[0017] Furthermore, it is proposed that the handle and the at least one first jaw are integral with respect to each other. They therefore consist of one part, are strong and unbreakable, are manufactured from the same piece of material and / or are arranged without joints or seams. This may not only provide a particularly reliable connection between the first jaw and the handle, but may also allow particularly easy and efficient manufacturing.

[0018] Thus, a particularly good screw can be manufactured with particularly low effort and cost. In particular, the proposed mechanical clamping can provide a particularly high joint quality and robustness, which can also allow the screw to be used in harsh installation conditions without a significant possibility of thread stripping.

[0019] The first claw may protrude radially from the shank, or may be flush with the shank. The shank is an elongated member and may in particular be substantially cylindrical, more preferably cylindrical, possibly including a groove for accommodating a separate spiral element. The tip and the rear end constitute the opposite ends of the shank, respectively. The shank comprises a longitudinal axis extending through the rear end of the shank and through the tip of the shank. The tip is the end of the shank that is intended to be first inserted into the drilled hole when installing the screw. The shank may be pointed at the tip, but is preferably blunt at the tip, in particular if the screw is a concrete screw. The screw also includes a drive portion for applying torque on the shank. The drive portion may be located at the rear end of the shank, for example, if the drive portion is a head, but it may also be located within the shank, for example, if the screw is a headless screw.

[0020] The first jaw, and if present, also the second jaw, can be continuous or discontinuous (so that the circumferential connection is interrupted at a local point) alongside the individual helical elements.

[0021] The at least one thread is generally substantially helical, but may deviate from a strict mathematical helix, for example to provide additional functionality. The at least one thread surrounds the shank and the longitudinal axis of the shank, i.e. it spirals around the shank, in particular one or more turns, more preferably at least two or three turns. The thread is an external thread. It projects radially from the shank and may engage a matching internal thread.

[0022] At least one thread is preferably continuous, but may also have discontinuities. For example, it may have a sawtooth structure at least in certain areas.

[0023] For a particularly simple design, the screw may comprise only a single thread. However, it is also possible to provide additional threads, for example for additional functions. These additional threads may overlap or not overlap axially with respect to the at least one thread and may be designed differently from the at least one thread or similarly thereto.

[0024] The separate spiral element and the shank are non-integral to each other. Therefore, they are separate components and / or at least one joint or seam is provided between them. In particular, the separate spiral element and the shank can be manufactured from different pieces of material and / or manufactured separately from each other and then joined. In particular, the separate spiral element is non-integrally connected to the shank, in particular so as to transfer a pull-out force oriented along the longitudinal axis of the shank from the shank to the separate spiral element, so that the pull-out load can be transferred from the shank to the surrounding substrate through the separate spiral element. In this regard, the pull-out force is a rearward axial force.

[0025] The individual helical element extends along the longitudinal axis of the shank. The individual helical element is usually substantially helical, but may deviate from a strict mathematical helix, for example in order to provide additional functionality. The individual helical element surrounds the shank and the longitudinal axis of the shank, i.e. it spirally rotates around the shank, in particular one or more turns. In particular, the individual helical element may have a crest that projects radially from the shank and forms a thread, and a root that is embedded in the shank, preferably in a groove that is advantageously provided in the shank.

[0026] The individual spiral elements constitute at least a part of at least one thread, in particular at least one spiral portion. Thus, the thread may also have additional spiral portions which are not formed by the individual spiral elements and which may be located in front of (i.e. towards the end) and / or behind the individual spiral elements. However, the individual spiral elements may also constitute the entirety of at least one thread, which is preferred.

[0027] As used in this document, “axial”, “longitudinal”, “radial” and “circumferential” directions may particularly refer to the longitudinal axis of the shank, which may coincide with the longitudinal axis of the entire screw.

[0028] Particularly preferably, the first claw extends along at least 1 / 36 of a turn of the individual spiral element. Thus, the first claw spans an angle of at least 10° around the longitudinal axis of the shank. More preferably, the first claw extends along at least 1 / 16 of a turn of the individual spiral element. It can also extend along one or more turns of the individual spiral element, preferably along all the individual spiral elements. Thus, the first claw has a relatively long spiral extension, thereby providing a particularly effective fixation of the individual spiral element to the shank. In particular, a "fail-safe" design can be provided, which is still effective even when the individual spiral element should break. For the same reason, it is preferred that the first claw extends along at least 20% or at least 50% of the total axial length of the individual spiral element, more preferably along the entire individual spiral element. Preferably, the first claw is positioned at least close to the end of the individual spiral element towards the end. As described above, the first claw can have discontinuity.

[0029] According to another preferred embodiment of the invention, the screw further comprises at least one second claw, which protrudes from the shank and has a radial and axial overlap with the separate spiral element (in particular for fixing the separate spiral element to the shank), wherein the shank and the at least one second claw are integral with each other, and wherein the at least one first claw and the at least one second claw point in opposite axial directions, respectively. For example, the first claw may point to the end of the shank, while the second claw may point to the rear end of the shank, or vice versa. Thus, opposite sides of the separate spiral element can be clamped, which can provide a particularly good fixation of the separate spiral element on the shank.

[0030] At least one second claw overlaps with the individual spiral element radially (i.e. in the direction perpendicular to the longitudinal axis) and axially (i.e. in the direction of the longitudinal axis). Due to the axial overlap, there is an axial portion occupied by the second claw and the individual spiral element, and in this axial portion, the individual spiral element is clamped between the second claw and the shank. Therefore, the second claw provides a kind of stable locking mechanism, which radially fixes the individual spiral element on the shank. In addition, the mechanism can further improve the frictional contact between the side surface of the individual spiral element and the shank, or if provided, it can further improve the meshing of the corresponding tooth portion on the individual spiral element and the shank. In addition, the radial overlap between the second claw and the individual spiral element can provide a stable locking mechanism, which can also axially fix the individual spiral element on the shank. Therefore, the force in the axial, radial and / or circumferential direction can be more effectively transmitted between the shank and the individual spiral element, which can provide even better screw performance.

[0031] The handle and the at least one second jaw are integral with respect to one another. They are therefore made of one piece, are solid and unbroken, are made from the same piece of material and / or are arranged without joints or seams. This not only provides a particularly reliable connection between the second jaw and the handle, but also enables particularly easy and efficient production.

[0032] If one of the claws, such as the first claw, points to the end, it can fix the individual spiral element to prevent axial displacement backwards. If one of the claws, such as the second claw, points to the rear end, it can fix the individual spiral element to prevent axial displacement forwards, that is, to the end.

[0033] The second jaw may protrude radially from the shank, or may be flush with the shank.

[0034] Particularly preferably, the second claw extends along at least 1 / 36 of a turn of the individual spiral element. Thus, the second claw spans an angle of at least 10° around the longitudinal axis of the handle. More preferably, the second claw extends along at least 1 / 16 of a turn of the individual spiral element. It can also extend along one or more turns of the individual spiral element, preferably along all the individual spiral elements. Thus, the second claw has a relatively long spiral extension, thereby providing a particularly effective fixation of the individual spiral element to the handle. In particular, a "fail-safe" design can be provided, which is still effective even when the individual spiral element should break. For the same reason, preferably, the second claw extends along at least 20% or at least 50% of the total axial length of the individual spiral element, more preferably along the entire individual spiral element. Preferably, the second claw is positioned at least close to the end of the individual spiral element towards the end. As described above, the second claw can have a discontinuity.

[0035] In particular, the individual spiral element can be sandwiched between the first jaw and the second jaw in the axial direction, wherein the axial sandwich structure consists of the first jaw, the second jaw and a portion of the individual spiral element adjacent to the first jaw and the second jaw.

[0036] Advantageously, the at least one first claw and the at least one second claw define an undercut groove in which the individual spiral element is arranged. Thus, the first claw and the second claw have a circumferential overlap in order to provide a receptacle, i.e. an undercut groove, for the individual spiral element. This can provide a particularly good fixation of the individual spiral element, since a commonly connected fixed spiral portion of the individual spiral element can be provided, which is fixed by both the first claw and the second claw. In particular, the root of the individual spiral element is arranged in the undercut groove. The bottom of the groove can be formed by the handle. The groove can generally be spiral, but can deviate from a strict mathematical spiral, for example in order to provide additional functionality.

[0037] For example, the groove can be a T-shaped groove, or it can have a circular cross section. However, preferably, the groove is a dovetail groove, which can provide a particularly good engagement with lower effort.

[0038] It is particularly preferred that the groove extends radially into the shank. Therefore, it protrudes radially into the generally (circular) cylindrical contour of the shank. This can provide a particularly good engagement of the root of a separate spiral element, because the claw is axially supported by the shank.

[0039] According to another preferred embodiment of the present invention, at least one tooth is arranged on the shank, which is engaged by a separate spiral element, in particular to transmit circumferentially oriented forces (relative to the longitudinal axis of the shank) between the shank and the separate spiral element. This can further improve the robustness of the screw and in particular the installation performance, because the installation will generate circumferential forces. At least one tooth extends circumferentially (relative to the longitudinal axis of the shank) and can be located in the shank (for example at the bottom of the groove) and / or in one or both of the first and second claws (integral to the shank). The separate spiral element has at least one reverse tooth, which meshes with at least one tooth arranged on the shank. At least one tooth can have radially or / and axially protruding teeth (both relative to the longitudinal axis of the shank). In particular, at least one tooth can extend into the groove. The tooth can extend roughly along the separate spiral element, but it may also be shorter. For example, it can extend only along the first 1-3 turns of the separate spiral element located closest to the end of the shank.

[0040] It is particularly preferred that the shank consists of a first material and the individual spiral elements consist of a second material, wherein the first material and the second material are different materials. Using different materials for different elements allows conflicting objectives regarding materials to be resolved in a particularly easy manner.

[0041] The first material (i.e. the material of the handle) can be, for example, a metallic material (e.g. steel, aluminum, titanium) or a plastic material. The second material (i.e. the material of the individual spiral elements) can be, for example, a metallic material (steel, aluminum, titanium, hard metal), a plastic material or a ceramic material.

[0042] In particular, the proposed concept can be used for screws for indoor applications.In this case, both the first material and the second material may preferably be carbon steel, but are preferably of different types.

[0043] The proposed concept can also be used for screws for outdoor applications. In this case, the following configurations are especially conceivable:

[0044] • The first material and the second material are both stainless steel, but are preferably of different types.

[0045] • The first material (ie the material of the shank) is carbon steel provided with an anti-corrosion coating applied on the shank, whereas the second material (ie the material of the separate helical elements) is stainless steel.

[0046] • The first material (ie the material of the shank) is stainless steel, whereas the second material (ie the material of the individual helical elements) is carbon steel provided with an anti-corrosion coating applied on the individual helical elements.

[0047] In the case of outdoor applications, providing corrosion protection to the threads, either inherently or by means of a coating, can allow the full length of the embedded threads to be used to transfer the load.

[0048] Preferably, the first material and the second material are both metal materials, in particular steel.

[0049] The first material (i.e. the material of the handle) can, for example, be an austenite (e.g. 1.4404, 1.4301, 1.4529 or similar materials), a duplex (e.g. 1.4062, 1.4162, 1.4362, 1.4410, 1.4509 or similar materials), a ferrite (e.g. 1.4105, 1.4113, 1.4521 or similar materials) or a PH stainless steel (e.g. 15-5PH or similar materials).

[0050] The second material (i.e. the material of the individual spiral elements) can be, for example, an austenite (e.g. 1.4565 / 1.4566, 1.3808 or the like), a martensite (e.g. 1.4108, 1.4109, 1.4116, 1.4122, the steel grades described in US2020063231 A1) or a PH stainless steel (e.g. 17-7PH).

[0051] It is particularly advantageous if the second material (i.e. the material of the individual screw elements) is a steel material, preferably a stainless steel material, having a Vickers hardness between 550 HV10 and 800 HV10, preferably between 650 HV10 and 750 HV10, wherein the Vickers hardness is in particular in accordance with ISO 6507. Thus, the second steel material used for the threaded spiral has a higher hardness, which corresponds to a higher steel resistance, which is advantageous for efficient load transfer between the external thread and the internal base material thread, especially in the case of local or point-to-point contact. In addition, the high strength level of the individual screw elements can provide a particularly high degree of design freedom, for example with regard to the cross-sectional geometry of the individual screw elements. For example, the thread cross section of the individual screw elements can be made relatively narrow (a thread flank angle of 30°-45° instead of 40-50° can be envisaged), which still provides a high structural resistance, but the installation performance is improved due to the reduced self-tapping action.

[0052] According to another preferred embodiment of the invention, the first material (ie the material of the handle) is a steel material, preferably a stainless steel material, having a Vickers hardness between 250 HV10 and 800 HV10, wherein the Vickers hardness is in particular according to ISO 6507. This hardness range of the handle can provide sufficient robustness.

[0053] As already mentioned, the screw is preferably a concrete screw, i.e. a screw, in particular its thread, capable of at least partially self-tapping its mating internal thread groove in a concrete substrate. In particular, at least in some areas of the thread, more preferably at least in some areas of the thread located near the end, most preferably throughout the entire thread, the ratio of the maximum external thread diameter of the thread to the pitch of the thread may be between 1 and 2, in particular between 1.2 and 1.6. These are typical dimensions for concrete screws. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The invention is explained in more detail below with reference to preferred exemplary embodiments schematically depicted in the drawings.Within the scope of the invention, the individual features of the exemplary embodiments presented below may be implemented individually or in any combination.

[0055] Figure 1 is a side view of the screw.

[0056] Figure 2 yes Figure 1 Cross-sectional view AA of the screw, wherein the cross section is a longitudinal plane including the longitudinal axis of the screw.

[0057] Figure 3 and 4 Shows Figure 1 Detail of the middle area of ​​the screw, in Figure 3 In, according to Figure 1 In the cross-sectional view AA, wherein the cross-sectional plane is a longitudinal plane including the longitudinal axis of the handle, Figure 4 In, according to Figure 3 In the cross-sectional view BB, the cross section is a transverse plane perpendicular to the longitudinal axis of the handle.

[0058] Figure 5 In accordance with Figure 1 The cross-sectional view AA again shows Figure 1 Detail of the middle region of the screw, wherein the section plane is a longitudinal plane including the longitudinal axis of the shank, omitting the individual screw elements, and including dimensional indications.

[0059] Figure 6 and 7 Similar to Figure 5 The view shows Figures 1 to 5 A modification of the embodiment wherein Figure 6Individual spiral elements are omitted.

[0060] Figure 8 Similar to Figure 5 The view shows Figures 1 to 5 Another modification of the embodiment of .

[0061] Fig. 9 Similar to Figure 5 The view shows Figures 1 to 5 Another modification of the embodiment of .

[0062] Figures 10 to 12 Possible modifications of the cross-section of the individual spiral elements are shown.

[0063] Fig.13 and 14 Respectively similar to Figure 3 and Figure 4 The view shows Figures 1 to 5 Another modification of the embodiment of .

[0064] Figures 15 to 19 Shows Figures 1 to 5 Another modification of the embodiment of . Fig.15 is an isometric view with the individual spiral elements omitted. Fig.16 is similar to Figure 3 of the view. Fig.17 is another cross-sectional view, wherein the cross section is a longitudinal plane including the longitudinal axis of the handle, wherein the plane is parallel to Fig.16 The plane of the is slightly offset at an angle. Fig.18 is similar to Fig.17 , but with the individual spiral elements omitted. Fig.19 is based on Fig.18 BB, wherein the cross section is a transverse plane perpendicular to the longitudinal axis of the handle, also omitting the separate helical element.

[0065] Figures 20 to 22 Shows Figures 1 to 5 Another modification of the embodiment of . Fig. 20 is an isometric view with the individual spiral elements omitted. Fig.21 is similar to Figure 3 of the view. Fig. 22 is based on Fig.21 Cross-sectional view BB, wherein the cross section is a transverse plane perpendicular to the longitudinal axis of the handle. DETAILED DESCRIPTION

[0066] Figures 1 to 5An embodiment of a screw of the present invention is shown. The screw comprises an elongated shank 10 having a distal end 11. The distal end 11 is the front end of the shank 10, and when the screw is installed, the shank 10 is intended to be inserted into the drill hole with the distal end 11 first. The shank 10 also has a rear end 18, which is located on the shank 10, opposite the distal end 11. The screw also has a screw drive 19 connected to the shank 10, in the present case, for example, integrally connected, for applying torque to the shank 10. In the embodiment shown, the screw drive 19 is a hexagonal head located at the rear end 18, but this is only an example. Any other type of screw drive 19 can be used, such as an external type, such as hexagonal, line (ALH), square, or recessed head, such as Bristol, clutch, double hexagon, internal hexagon, internal torx, line (ALR), multi-drive (polydrive), Robertson, spline, TP3, etc. The screw drive 19 can also be located inside the shank 10 and / or away from the rear end 18, especially if the screw is headless and / or internally threaded.

[0067] The elongated handle 10 includes a longitudinal axis 99 extending in the longitudinal direction of the handle 10 and passing through the distal end 11 and the rear end 18 .

[0068] The screw further comprises a separate helical element 37, which is located on the shank 10 and surrounds the shank 10 and / or the longitudinal axis 99. In particular, the separate helical element 37 is coaxially arranged relative to the shank 10. The separate helical element 37 comprises a top 39 and a root 34. In particular, the top 39 is helical and radially adjoins the root 34, which is also helical. The root 34 is located radially inwardly of the separate helical element 37, i.e. it is closer to the longitudinal axis 99 of the shank 10 than the adjacent top 39.

[0069] The single helical element 37, in particular its top 39, constitutes at least a helical portion of the thread 30 of the screw. In the illustrated embodiment, the single helical element 37, in particular its top 39, constitutes all the threads 30 of the screw, but this is only an example, and the thread 30 may have an additional helical portion. The thread 30 is located on the shank 10, around the shank 10 and / or the longitudinal axis 99, and radially protrudes from the shank 10 relative to the longitudinal axis 99. The thread 30 is an external thread.

[0070] The individual helical elements 37 and the shank 10 are non-integral with respect to each other. Due to the latter, the thread 30 and the shank 10 are also non-integral with respect to each other, at least in regions.

[0071] The handle 10 is made of a first material. The individual spiral element 37 is made of a second material. In the present embodiment, the first material and the second material are different materials. The second material can be a metal material, preferably a steel material, most preferably a stainless steel. The first material can be a metal material, preferably a steel material, most preferably a stainless steel. The handle 10 and / or the individual spiral element 37 can also be provided with a corresponding coating, including one or more layers.

[0072] In the present embodiment, the individual helical element 37 and / or the thread 30 has a plurality of turns, namely about 8.5 turns. Preferably, at least two turns are provided. For example, the individual helical element 37 and / or the thread 30 spans the length l of the handle 10 in the axial direction (i.e. in a direction parallel to the longitudinal axis 99) s The thread 30 thus forms the main thread of the screw. The thread 30 may also span the length l of the shank 10. s 100%; preferably, it spans the length l of the handle 10 s at least 20% of the

[0073] While in the illustrated embodiment no additional threads are shown, the screw may also have additional threads, which may be formed integrally or non-integrally with respect to the shank 10 .

[0074] The shank 10 is provided with a helical groove 40 which surrounds the longitudinal axis 99 of the shank 10 and protrudes radially into the shank 10 on the side surface of the shank 10. The individual helical element 37, in particular its root 34, is arranged in the groove 40, while its top 39 protrudes from the shank 10. The screw is provided with a first claw 51 and a second claw 52, ​​wherein both the first claw 51 and the second claw 52 fix the individual helical element 37 on the shank 10, in particular they fix the individual helical element 37, in particular its root 34, in the groove 40.

[0075] The first claw 51 and the second claw 52 both protrude from the shank 10 and are integral with the shank 10. The first claw 51 and the second claw 52 both have an axial overlap (relative to the longitudinal axis 99) and a radial overlap (relative to the longitudinal axis 99) with the adjacent individual spiral element 37, in particular its root 34. The first claw 51 and the second claw 52 both clamp the individual spiral element 37, in particular its root 34, on the shank 10. In particular, they clamp the individual spiral element 37, in particular its root 34, in the radial and axial directions (relative to the longitudinal axis 99). In the present embodiment, this clamping is tight. Therefore, the first claw 51 and the second claw 52 clamp the individual spiral element 37, in particular its root 34, radially close to the shank 10 and in the axial direction. However, some illusions may be provided, for example due to manufacturing reasons or / and to provide additional functions. The clamping of the individual spiral element 37, in particular its root 34, in the axial direction occurs between the first claw 51 and the second claw 52.

[0076] The first claw 51 projects forward, i.e., towards the end, i.e., towards the end 11, while the second claw 52 projects backward, i.e., towards the rear end 18, in particular towards the head. The first claw 51 clamps the side of the individual spiral element 37 facing backward, while the second claw 52 clamps the side of the individual spiral element 37 facing forward, i.e., towards the end.

[0077] In this embodiment, both the first claw 51 and the second claw 52 extend along the single spiral element 37, that is, both the first claw 51 and the second claw 52 have the same number of turns as the single spiral element 37, wherein the first claw 51 and the second claw 52 sink near the end 11. However, this is only an example.

[0078] The first claw 51 and the second claw 52 both face and preferably abut the individual spiral element 37. The first claw 51 and the second claw 52 both abut the groove 40, the first claw 51 delimits the groove 40 rearwardly, and the second claw 52 delimits the groove forwardly (i.e., toward the end), i.e., the first claw 51 forms the side of the groove 40 facing forwardly (i.e., facing the end), and the second claw 52 forms the side of the groove 40 facing rearwardly. The first claw 51 and the second claw 52 form an undercut structure at the groove 40, so the groove is an undercut groove 40. In the present embodiment, the undercut structure of the groove 40 extends along the individual spiral element 37, but this is only an example. The first claw 51, the second claw 52 and the undercut groove 40 are shown to be continuous, but discontinuities, such as gaps, may also be provided. The undercut structure of the groove 40 fixes the individual spiral element 37, in particular its root 34, on the handle 10. The bottom of the groove 40 is formed by the handle 10, in particular by its side surface. In the illustrated embodiment, the undercut groove 40 is a dovetail groove 40.

[0079] In particular, the flank angle of the groove 40 can be approximately the same as the thread flank angle of the root 34 of the separate screw element 37 in order to achieve a particularly effective clamping.

[0080] The screw is a concrete screw, ie the thread 30 is capable of tapping, in particular cutting, a corresponding mating thread in the concrete substrate. The thread 30 has an outer thread diameter d tr At least near the end 11 of the unmounted screw, the ratio of the maximum external thread diameter dtr of the thread 30 to the pitch ptr of the thread 30 is between 1 and 2, in particular between 1.2 and 1.6. In particular, the top 39 of the individual screw elements 37 can cut into the substrate and / or form a secure interlock with the substrate.

[0081] The thread 30 may be a mathematically strict helical shape, but may also deviate from a helical shape, which may, for example, provide additional functionality.

[0082] Preferably, the first and second jaws 51, 52 form the main connection between the individual screw elements 37 and the handle 10. Additional material connections (such as gluing, or material connections based on heat input, such as brazing or welding) may also be provided, but are preferably absent.

[0083] exist Figures 1 to 5 In the embodiment of the present invention, the first claw 51 and the second claw 52 radially protrude above the adjacent side surface of the handle 10, that is, they each form a raised shoulder protruding radially from the handle 10. However, the first claw 51 and the second claw 52 can also be flush with the adjacent side surface of the handle 10, such as Figure 6 and Figure 7 shown. Figure 6 and 7 Modifications are possible in combination with all other presented embodiments.

[0084] In all presented embodiments, the geometry of the groove 40 and / or the individual spiral elements 37 can preferably be selected within the following ranges (where db is the nominal bore diameter and ptr is the pitch of the thread 30, and the remaining parameters are in particular in the figures: Figures 5 to 7 specified):

[0085] -d s / d b =0.7–0.99 (ratio of shank diameter to nominal drill hole diameter).

[0086] -2h g / d s = 0.1–0.4 (2x the ratio of groove depth to shank diameter).

[0087] -d max / d b= 0.9–1.2 (ratio of maximum transverse clamping diameter to nominal drill hole diameter). Note that if d max / d b >1.0, an additional thread-like interaction with the surrounding substrate is provided, wherein the first jaw 51 and / or the second jaw 52 acts on and preferably cuts the surrounding substrate, which is preferably concrete, as already described.

[0088] -w c / p tr =0.2–0.7 (ratio of clamping width to thread pitch).

[0089] - Depth of the groove 40 (h g ) may be constant along the entire groove 40. Alternatively, the groove 40 may be sunken, particularly in its starting portion near the end 11. This sunken groove 40 may be accompanied by a sunken thread 30 in its starting portion near the end 11, i.e. the outer thread diameter dtr tapers toward the end 11. Accordingly, the starting portion of the thread 30 will gradually cut into the surrounding base material.

[0090] -h sg / h s = 0.2 - 1.0 (ratio of the radial embedding depth of the individual spiral element 37 to the total height of the individual spiral element 37). Note that h sg / h s =1.0 means that the individual helical elements 37 are completely sunk into the shank 10, which may be the case near the tip 11. sg / h s =0.2 means that 20% of the total profile height of the height of the individual helical element 37 is located within the shank 10 and is available for the mechanical connection between the individual helical element 37 and the shank 10 .

[0091] exist Figures 1 to 5 In the embodiments, and in Figure 6 and 7 In the variant shown, the groove 40 is a dovetail groove 40. However, it is possible to provide other groove cross-sections, such as a T-shaped groove 40 (see Figure 8 ) or a groove 40 having a circular cross section (see Fig. 9 ). Figure 8 and 9 The modifications are respectively possible in combination with all other proposed embodiments.

[0092] Preferably, the cross section of the groove 40 corresponds to the cross section of the root 34 of the individual spiral element 37. In particular, both cross sections are generally identical.

[0093] exist Figures 1 to 5 In the embodiments, and in Figure 6and 7 In the variant shown, the individual spiral elements 37 have a generally triangular cross-section, i.e. an isosceles triangle cross-section, wherein two sides of equal length are provided by the forward-facing side and the rearward-facing side of the separate spiral element 37, respectively. However, other cross-sections may be provided for the individual spiral elements 37, such as a scalene triangle inclined rearwardly (see Fig.10 ), a scalene triangle tilted forward (see Fig.11 ) or a triangle with concave sides (see Fig.12 ). Fig.10 , Fig.11 or Fig.12 The modifications can each be combined with all other presented exemplary embodiments.

[0094] exist Figures 1 to 5 In the embodiment of the present invention, axial loads and radial loads between the separate spiral element 37 and the shank 10 can be transmitted through a stable connection, i.e., through interlocking elements (in particular, through the interlocking of the separate spiral element 37 as the first element and the first claw 51 and the second claw 52 as the second element). On the other hand, loads in the circumferential direction, such as torsional loads occurring during screw installation, can be transmitted through friction between the separate spiral element 37 as the first friction element and the first claw 51, the second claw 52 and / or the shank 10 as the second friction element. In order to further increase the friction, the cross-section of the root 34 of the separate spiral element 37 and the corresponding groove 40 can be modified. Fig.13 and 14 , where the root 34 has a hexagonal cross-section, with the base of the root tapering towards the longitudinal axis 99 when viewed in cross-section. Due to this taper, friction increases when the individual helical elements 37 are pushed radially towards the longitudinal axis 99, similar to a tapered interference fit / V-band mechanism. Fig.13 and 14 Modifications can be combined with all other presented embodiments.

[0095] In order to further enhance the transmission of circumferentially oriented loads between the individual screw element 37 and the shank 10, such as torsional loads generated during screw installation, the screw can be provided with teeth 55 or 56 associated with the shank 10 and the individual screw element 37, in particular its root 34, meshing with these teeth.

[0096] exist Figures 15 to 19In the embodiment of the present invention, two tooth portions 55' and 55" are provided, both of which have teeth protruding axially (relative to the longitudinal axis 99 of the handle 10). The tooth portion 55' is arranged in the first claw 51 and includes teeth protruding forward, i.e., toward the end, and the tooth portion 55" is arranged in the second claw 52 and includes teeth protruding backward. The tooth portions 55' and 55" are both engaged with the separate spiral element 37, in particular with its root 34, thereby providing a bilaterally stable laterally connected connection between the separate spiral element 37 and the handle 10. The tooth portions 55' and 55" both extend into the groove 40. In the embodiment shown, the tooth portions 55' and 55" both extend roughly along the separate spiral element 37, but they can also be shorter. For example, they can extend only along the first 1-3 turns of the separate spiral element 37 located closest to the end 11.

[0097] exist Figures 20 to 22 In the embodiment of the present invention, a toothing 56 having teeth protruding radially outward (relative to the longitudinal axis 99 of the shank 10) is provided on the shank 10, i.e. at the bottom of the groove 40. The toothing 56 extends into the groove 40 and meshes with the individual spiral element 37, in particular with its root 34, thereby providing a radially stable connection between the individual spiral element 37 and the shank 10. In the embodiment shown, the toothing 56 extends substantially along the individual spiral element 37, but it can also be shorter. For example, it can extend only along the first 1-3 turns of the individual spiral element 37 located closest to the end 11.

[0098] Figures 15 to 19 The modifications of 20 to 22 can each be combined with all other presented embodiments, or they can be combined with each other.

Claims

1. Screws, including a handle (10) having a distal end (11), a rear end (18) located opposite the distal end (11) and a longitudinal axis (99) extending through the rear end (18) and through the distal end (11), - at least one thread (30) arranged on the shank (10), surrounding the shank (10) and protruding from the shank (10), and a separate helical element (37) which is arranged non-integrally on the shank (10), wherein the separate helical element (37) surrounds the shank (10), protrudes from the shank (10) and constitutes a part of the at least one thread (30), - wherein the screw further comprises at least one first claw (51) which projects from the shank (10) and has a radial and axial overlap with the separate spiral element (37), - wherein the handle (10) and the at least one first jaw (51) are integral with respect to one another, - wherein the shank (10) is provided with a helical groove (40) which surrounds the longitudinal axis (99) of the shank (10) and protrudes radially into the shank (10) on a side surface of the shank (10), wherein a separate helical element (37) is arranged in the groove (40), It is characterized in that The groove (40) is sunken in its starting part located near the end (11), wherein this sunkenness of the groove (40) is accompanied by a sunkenness of the thread (30) in its starting part located near the end (11).

2. The screw according to claim 1, It is characterized in that The first claw (51) extends along at least 1 / 36 of a turn of the individual spiral element (37).

3. The screw according to any one of the preceding claims, It is characterized in that - the screw further comprises at least one second claw (52) which projects from the shank (10) and has a radial and axial overlap with the separate spiral element (37), - wherein the handle (10) and the at least one second jaw (52) are integral with respect to one another, - and wherein the at least one first claw (51) and the at least one second claw (52) point in opposite axial directions, respectively.

4. The screw according to claim 3, It is characterized in that The second claw (52) extends along at least 1 / 36 of a turn of the single helical element (37).

5. The screw according to claim 3, It is characterized in that The at least one first claw (51) and the at least one second claw (52) form an undercut structure at the groove (40), so the groove is an undercut groove, and the separate spiral element (37) is arranged in the undercut groove.

6. The screw according to claim 5, It is characterized in that The groove (40) is a dovetail groove.

7. The screw according to claim 5, It is characterized in that The groove (40) extends radially into the shank (10).

8. The screw according to any one of claims 1 to 2, It is characterized in that At least one toothing (55; 56) is provided on the shank (10) and engages with the separate screw element (37).

9. The screw according to any one of claims 1 to 2, It is characterized in that The handle (10) is composed of a first material and the separate spiral element (37) is composed of a second material, wherein the first material and the second material are different materials.

10. The screw according to claim 9, It is characterized in that The first material and the second material are both metal materials.

11. The screw according to claim 10, It is characterized in that The first material and the second material are both steel.

12. The screw according to claim 11, It is characterized in that The second material is a steel having a Vickers hardness between 550 HV10 and 800 HV10, and The first material is a steel having a Vickers hardness between 250 HV10 and 800 HV10.

13. The screw according to claim 12, It is characterized in that The second material is a steel having a Vickers hardness between 650 HV10 and 750 HV10.

14. The screw according to any one of claims 1 to 2, It is characterized in that The screws are concrete screws, and / or At least in some areas of the thread (30), the maximum external thread diameter (d tr ) and the pitch (p) of the thread (30) tr ) ratio is between 1 and 2.

15. The screw according to claim 14, It is characterized in that The maximum external thread diameter (d tr ) and the pitch (p) of the thread (30) tr ) ratio is between 1.2 and 1.6.

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