Hybrid screw with a separating wedge-shaped groove

Abstract

The present invention relates to a screw having: a shank (10), wherein the shank has a tip (11), a rear end (18), and a longitudinal axis (99) extending through the tip and through the rear end, wherein the tip and the rear end are opposite ends of the shank; and a thread (30) connected to the shank and wound around the shank, wherein a wedge-shaped groove (40) is provided in the shank, the wedge-shaped groove being wound around the shank and extending alongside at least one section of the thread, wherein the wedge-shaped groove is defined by wedge-shaped sides (44) that taper rearwardly for wedging into a grout shell surrounding the shank. At least one ridge (46) is provided in the wedge-shaped groove, wherein the ridge separates the wedge-shaped groove.

Description

Technical Field

[0001] The present invention relates to a screw. Background Art

[0002] Recently, DE 10311471 A1, EP 2138728 A2, EP 2354567 A1, US 5885041A1 and DE19820671 A1 each describe screw-shaped elements intended to be installed in drill holes filled with chemicals.

[0003] US 9464524 B discloses an anchor rod for chemical anchoring. Summary of the Invention

[0004] It is considered that an object of the present invention is to provide a screw having an additional grouting wedge mechanism, which has particularly good performance with particularly little workload.

[0005] This object is achieved by a screw having: a shank, wherein the shank has a tip, a rear end, and a longitudinal axis extending through the tip and through the rear end, wherein the tip and the rear end are opposite ends of the shank; and a thread connected to the shank and wound around the shank, wherein a wedge-shaped groove is provided in the shank, the wedge-shaped groove is wound around the shank and extends beside at least a section of the thread, wherein the wedge-shaped groove is defined by wedge-shaped sides that gradually narrow backward for wedging into a grouting shell surrounding the shank, at least one ridge is provided in the wedge-shaped groove, and the ridge separates the wedge-shaped groove.

[0006] The present invention relates to a screw with an additional anchoring mechanism, that is, a screw with a wedge mechanism. This wedge mechanism includes a grouting shell surrounding the screw shank and wedge-shaped sides located at a spiral wedge-shaped groove in the screw shank and intended to radially wedge into the grouting shell when the shank is axially loaded in the pulling-out direction (i.e., when the shank is loaded backward). The present invention is based on the fact that typical hardened grout may have only a limited degree of ductility. Therefore, a continuous spiral string of hardened grout arranged in a corresponding spiral wedge-shaped groove cannot be easily expanded - rather, the spiral string first needs to break before the string can be wedged out. Therefore, dividing the spiral grout string into individual segments (i.e., thin layers) may be essential for activating the wedge mechanism.

[0007] In view of this, the present text proposes to provide at least one axially extending ridge within the wedge-shaped recess, which, depending on its height and geometry, can act as a predefined breaking line for the helical grout string or can initially subdivide the helical grout string into segments. Thus, at least one ridge provides segmentation of the helical grout string, which initiates the wedge mechanism - and this occurs in a particularly well-defined manner (as opposed to random breaking). Thus, particularly good performance can be achieved in a particularly simple manner, especially with a particularly small variation in load-bearing capacity.

[0008] The shank is an elongate member and can in particular be generally cylindrical, more preferably annularly cylindrical. The tip and the rear end respectively form opposite ends of the shank. The shank includes a longitudinal axis that extends 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 drill hole when installing the screw. The shank may be pointed at the tip, but is preferably blunt or frustoconical at the tip, especially in the case where the screw is a concrete screw. The screw will also include a drive portion for applying torque to the shank. For example, in the case where the drive portion is a head, the drive portion can be located at the rear end of the shank, but in the case where the screw is a headless screw, for example, the drive portion can also be located within the shank.

[0009] The thread is generally helical in shape, but can deviate from a strict mathematical helix, for example in order to provide additional functionality. The thread winds around the shank and the longitudinal axis of the shank, i.e., it rotates helically around the shank, especially for one or more turns, more preferably for at least two or three turns. The thread is an external thread. It projects radially from the shank and can engage a matching internal thread. The thread is connected to the shank in order to transmit a pull-out load directed backwards. The thread can be integral with the shank, or it can consist of one or more separate parts that are not integrally connected to the shank.

[0010] The thread is preferably continuous, but can also have interruptions. For example, it can have a serrated structure at least in some regions, especially within the thread start. The screw can also include a cutting body embedded in the thread, especially within the thread start. For a particularly simple design, the screw can include only a single thread. However, it is also possible to provide additional threads, for example for additional functionality.

[0011] The wedge-shaped groove is generally substantially helical, but may deviate from a strict mathematical helix, for example in order to provide additional functionality. The wedge-shaped groove winds around the shank and the longitudinal axis of the shank, i.e., it rotates helically around the shank, in particular by one or more turns, more preferably by at least two or three turns. The wedge-shaped groove is cut into the shank, i.e., its lateral surface. The wedge-shaped groove extends beside at least one section of the thread, i.e., the thread and the wedge-shaped groove wind around the shank adjacent to each other in at least one section of the shank. The wedge-shaped groove is in particular delimited by wedge-shaped sides that taper backwards. This wedge-shaped side facing backwards (i.e., towards the rear end of the shank) delimits the wedge-shaped groove towards the tip. In addition, the wedge-shaped groove may be delimited towards the rear end of the shank by a side facing forwards, and optionally at the bottom of the groove by a bottom surface. The wedge-shaped side, the side facing forwards and / or the bottom surface wind around the shank. Generally, these sides are substantially helical, but may deviate from a strict mathematical helix, for example in order to provide additional functionality. The wedge-shaped sides taper backwards, i.e., they taper towards the rear end of the shank. Thus, the distance of the wedge-shaped sides from the longitudinal axis may decrease as they approach the rear end of the shank in the axial direction. Thus, the wedge-shaped sides form a wedge that can wedge radially outwards into the grout shell surrounding the shank when the shank is axially loaded backwards.

[0012] The grout shell is a hardened block shell arranged in the borehole. The grout may be, for example, mortar or synthetic resin.

[0013] Throughout this document, wherever the terms "axial", "longitudinal", "radial" and "circumferential" are used, this may in particular refer to the longitudinal axis of the shank, which generally coincides with the longitudinal axis of the screw.

[0014] Preferably, the ridge may extend parallel to the longitudinal axis. This can effectively counteract the unwanted interaction of the grout segments.

[0015] The ridge preferably projects from the wedge-shaped side. Thus, there are regions of the wedge-shaped side adjacent to both sides of the ridge. Thus, the ridge is arranged particularly close to the location where separation is required, which can further improve the effectiveness of the wedge mechanism. When the ridge projects from the wedge-shaped side, the ridge may also extend into other regions of the wedge-shaped groove.

[0016] The ridge may be recessed into the wedge-shaped groove. In this case, the ridge does not separate the helical grout string from the start, but can provide a predetermined fracture line at which the grout string breaks into segments. Alternatively, the ridge may be flush with its surroundings (i.e., the adjacent regions). In this case, the ridge may provide a higher degree of segment separation at the beginning of the installation process.

[0017] According to another preferred embodiment of the present invention, a plurality of ridges are provided in the wedge-shaped groove, wherein the ridges separate the wedge-shaped groove. Preferably, at least one ridge is provided per turn of the wedge-shaped groove. This results in particularly fine granulation segmentation, which may further enhance the effectiveness of the wedge mechanism. If a plurality of ridges are provided, at least one ridge may be configured as described herein for a single ridge. Preferably, all ridges are configured in this manner.

[0018] As already mentioned above, the screw is preferably a concrete screw, i.e., a screw, especially its thread, capable of at least partially tapping its mating internal thread groove in the concrete substrate. In particular, at least in some regions of the thread, more preferably at least in some regions of the thread located near the tip, and most preferably throughout the thread, the ratio of the maximum outer thread diameter of the thread to the pitch of the thread can be between 1 and 2, especially between 1.2 and 1.6. These are typical dimensions for concrete screws. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be explained in more detail below with reference to preferred exemplary embodiments schematically depicted in the drawings. Within the scope of the present invention, the various features of the exemplary embodiments presented below can be implemented individually or in any combination.

[0020] Figure 1 is an isometric view of a screw according to a first embodiment.

[0021] Figure 2 is a side view of a screw according to a first embodiment.

[0022] Figure 3 is a longitudinal section of a screw according to a first embodiment, taken according to Figure 2 A-A in and including the longitudinal axis of the screw shank.

[0023] Figure 4 is a cross-sectional view perpendicular to the longitudinal axis of the screw shank of a screw according to a first embodiment, taken according to Figure 2 E-E in.

[0024] Figure 5 shows a screw according to a first embodiment arranged in a drill hole and embedded in a grout shell,

[0025] Figure 6 is a detail of a screw according to a first embodiment, in a longitudinal section including the longitudinal axis of the screw shank.

[0026] Figure 7 is another detail of a screw according to a first embodiment, in a longitudinal section including the longitudinal axis of the screw shank.

[0027] Figure 8Is an isometric view of a screw according to the second embodiment. Detailed implementation

[0028] Figures 1 to 7 Shows a first embodiment of a screw. The screw includes an elongated shank 10 having a tip 11. The tip 11 is the front end of the shank 10, and when installing the screw, the shank 10 is intended to be inserted with the tip 11 first inserted into the drill hole 90. The shank 10 also has a rear end 18 that is positioned opposite the tip 11. In particular, the shank 10 can be generally annularly cylindrical. The screw additionally has a screw drive portion 19 connected to the shank 10, integrally connected in the current case for example, for applying torque to the shank 10. In the illustrated embodiment, the screw drive portion 19 is a hex head located at the rear end 18, but this is only an example. Any other type of screw drive portion 19 can be used, such as an external type, such as hexagon, wire (ALH), square, or an internal hexagon head, such as Bristol, clutch, double hexagon, internal hexagon, internal spline, wire (ALR), multi-drive, Robertson, spline, TP3, etc. The screw drive portion 19 can also be located within the shank 10 and / or away from the rear end 18, especially in the case where the screw is headless and / or has internal threads.

[0029] The elongated shank 10 includes a longitudinal axis 99 that extends in the longitudinal direction of the shank 10 and passes through both the tip 11 and the rear end 18.

[0030] The screw additionally includes threads 30 that are located on the shank 10, wound around the shank 10 and / or the longitudinal axis 99, and radially project from the shank 10 relative to the longitudinal axis 99. In particular, the threads 30 are arranged coaxially with respect to the longitudinal axis 99. The threads 30 are external threads. The threads 30 are generally helical. However, it may also deviate from a strict mathematical helix, for example for additional functionality. In the present embodiment, the shank 10 and the threads 30 are integral. However, alternatively, at least one section of the threads 30 or all of the threads 30 may be separated from the shank 10. However, in the present embodiment, the threads 30 are shown as an integral part, which may also be composed of separate elements. In particular, the shank 10 and / or the threads 30 are composed of a metallic material, preferably composed of steel, and most preferably composed of stainless steel. The shank 10 and / or the threads 30 may also have a corresponding coating including one or more layers.

[0031] In the present embodiment, the threads 30 are shown as continuous. However, they can also be discontinuous, for example to provide serrations.

[0032] However, in the illustrated embodiment, no additional threads are shown, and the screw may also have additional threads formed integrally or non-integrally with respect to the shank 10.

[0033] The wedge-shaped groove 40 is provided in the shank 10, wherein the wedge-shaped groove 40 projects radially into the shank 10 relative to the longitudinal axis 99. The wedge-shaped groove 40 extends beside the thread 30 and is located on the side of the thread 30, on the side of at least one of its sections. Like the thread 30, the wedge-shaped groove 40 thus winds around the shank 10 and / or the longitudinal axis 99, and the wedge-shaped groove 40 is generally helical (similarly, it may deviate from a strict mathematical helix). The helical wedge-shaped groove 40 is arranged coaxially relative to the longitudinal axis 99. In particular, the wedge-shaped groove 40 extends parallel beside the thread 30. In particular, the wedge-shaped groove 40 and the thread 30 have the same pitch.

[0034] The wedge-shaped groove 40 is bounded by a front-facing side 41 and a rear-facing side 44. Although in the illustrated embodiment, the front-facing side 41 merges into the rear-facing side 44, it is also possible to provide a bottom surface that is adjacent to both the side 41 and the side 44 and is located between the side 41 and the side 44, and the bottom surface defines the bottom of the wedge-shaped groove 40. Since the wedge-shaped groove 40 is generally helical, the front-facing side 41, the rear-facing side 44, and / or the bottom surface are also so.

[0035] The rear-facing side 44 is tapered backward, that is, when observed in a longitudinal section containing the longitudinal axis 99, the distance from it to the longitudinal axis 99 decreases towards the rear end 18 of the shank 10. In other words, the rear-facing side 44 converges towards the rear end 18 of the shank 10, and the focus of the convergence is preferably the longitudinal axis 99 of the shank 10.

[0036] The rear-facing side 44 forms a helical wedge that can radially wedge outwards into the grout shell 91 surrounding the shank 10 when the shank 10 is loaded backward (backward can be considered as the direction parallel to the longitudinal axis 99, from the tip 11 of the shank 10 to the rear end 18, that is Figure 7 the direction indicated by the medium thick arrow. The backward direction is also the pulling-out direction). The side 44 can thus form an additional anchoring mechanism for anchoring the shank 10 in the grout bore 90, which is also effective in addition to the interlocking of the thread 30 with the wall of the bore 90. The side 44 is thus a wedge-shaped side 44 for wedging into the grout shell 91 surrounding the shank 10.

[0037] In the case of the axial displacement of the shank 10 in the substrate, the wedge-shaped thin layer of the grout shell 91 can be radially displaced, which occurs, for example, during a tensile load and especially under cracked concrete conditions. As a result, friction and / or a deadlock reaction will occur between the shank 10 and the bore wall, which can provide an additional load transfer mechanism between the screw and the substrate.

[0038] As in Figure 7It can be seen particularly clearly that the buffer zone 49 is provided between the wedge-shaped side surface 44 and the thread 30 positioned adjacent to the wedge-shaped side surface 44, particularly axially therebetween. The buffer zone 49 abuts the wedge-shaped side surface 44, i.e., at its rear edge, and further abuts the thread 30, i.e., at its front edge, particularly the rear-facing side of the thread 30. The buffer zone 49 is thus sandwiched between the wedge-shaped side surface 44 and the thread 30. In the buffer zone 49, the handle 10 has a smaller backward taper compared to the wedge-shaped side surface 44. Accordingly, the taper angle measured with respect to the longitudinal axis of the handle 10 is smaller in the buffer zone 49 than at the wedge-shaped side surface 44. In particular, the taper and / or the taper angle may be zero in the buffer zone 49, as shown in this embodiment. In this case, the buffer zone 49 may have a generally annular cylindrical transverse surface, as shown in this embodiment.

[0039] The buffer zone 49 provides an offset in the longitudinal direction between the wedge-shaped side surface 44 and the thread 30. When the handle 10 is loaded backward, i.e., loaded in the pulling-out direction shown by the thick solid arrow in Figure 7 this offset can counteract the collision of the thin layer of grout shell wedged by the wedge-shaped side surface 44 with the large surface of the thread 30. As a result, the thin layer can remain in contact with both the handle 10 and the surrounding substrate and continue to transmit the radial load.

[0040] The backward taper of the rear side of the thread 30 is greater than the backward taper of the buffer zone 49.

[0041] The screw is a concrete screw, i.e., the thread 30 can be tapped, particularly to cut corresponding mating threads in a concrete substrate. In particular, the screw can be configured such that it can be anchored in a concrete drill hole solely by the engagement of the thread 30 (i.e., without grouting). A grout shell 91, i.e., a hardened mass shell, can be provided to provide additional anchoring by means of the mechanism described above.

[0042] The thread 30 has an external thread diameter d tr . The maximum external thread diameter d tr of the thread 30 and the pitch p tr of the thread 30 preferably have a ratio between 1 and 2, particularly between 1.2 and 1.6. The thread 30 can preferably adopt at least one of the following thread parameters:

[0043] ·d tr / d b = 1.1 to 1.3 (ratio of external thread diameter to drill hole diameter);

[0044] ·p tr / d b = 0.7 to 1.1 (ratio of thread pitch to drill hole diameter);

[0045] • Flank angle of thread 30 = 30° to 60°, wherein thread 30 may have an asymmetrical thread cross section, as shown, or a symmetrical cross section in an alternative embodiment.

[0046] The thread 30 has a plurality of turns, namely approximately six turns in the illustrated embodiment. Preferably, it has at least two turns. In this embodiment, the thread 30 longitudinally (ie, in a direction parallel to the longitudinal axis 99) spans the length l of the shank 10. s The thread 30 thus forms the main thread of the screw.

[0047] On the other hand, the number of turns of the wedge-shaped groove 40 is less than the number of turns of the thread 30 (in the present embodiment, the wedge-shaped groove 40 has approximately three turns), and the wedge-shaped groove 40 spans the length l of the shank 10. s In particular, the thread 30 extends closer to the rear end 18 of the shank 10 than the wedge-shaped groove 40 (and / or the wedge-shaped side 44). In particular, the thread 30 extends by at least one turn of the thread 30 (in the present embodiment, by approximately two turns) closer to the rear end 18 of the shank 10 than the wedge-shaped groove 40 (and / or the wedge-shaped side 44). Therefore, the thread 30 has at least one turn (in the present embodiment, two turns) axially located between the rear end 18 of the shank 10 and the wedge-shaped groove 40, and / or the thread 30 has at least one turn axially located between the rear end 18 of the shank 10 and the wedge-shaped side 44. In other words, the thread 30 extends by at least one pitch p of the thread 30 closer to the rear end 18 of the shank 10 than the wedge-shaped groove 40 and / or the wedge-shaped side 44. tr Due to this offset, the wedging mechanism provided by the wedging side surfaces 44 is concentrated deep in the borehole 90, where the substrate load is typically highest and / or where the substrate can typically absorb radial loads particularly well.

[0048] As already mentioned above, the thread 30 may be a mathematically strict helical shape, but it is also possible to deviate from the helical form, which may, for example, provide additional functionality. Likewise, the wedge-shaped groove 40 and / or the wedge-shaped side surface 44 may be a mathematically strict helical shape, but it is also possible to deviate from the helical form, which may, for example, provide additional functionality.

[0049] The screw includes a plurality of axially extending ridges 46 which are at least partially located within the wedge-shaped recess 40 and divide the wedge-shaped recess 40 into spirally continuous compartments or compartments. Figures 1 to 7 In the case of the first embodiment shown in FIG. 1 , the ridge 46 does not completely cover the longitudinal cross section of the wedge-shaped groove 40, and the ridge is slightly sunken into the wedge-shaped groove 40, for example, Figure 2 and Figure 3 In contrast, Figure 8In the second embodiment shown, the ridge 46 completely covers the longitudinal cross-section of the wedge-shaped recess 40 and is flush with the area around the handle 10, at least flush with the buffer zone 49. Further, in the case of the second embodiment, the ridge 46 is wider compared to the first embodiment.

[0050] In both embodiments, the ridge 46 forms a predetermined breaking position (in particular a predetermined breaking line) or a separating position (in particular a separating line) for the grouting shell 91 surrounding the handle 10, which enables the grouting shell 91 to be divided into individual segments when the handle 10 is loaded backwards, thereby activating the wedging mechanism.

[0051] In both embodiments, the ridge 46 extends longitudinally, in particular it extends substantially parallel to the longitudinal axis 99. In both embodiments, it projects radially outwards from the wedge-shaped side 44 and / or from the front-facing side 41 of the wedge-shaped recess 40.

[0052] Apart from the different designs of the respective ridges 46, the two embodiments shown are substantially the same. Thus, with regard to Figure 8 the details of the embodiment of Figures 1 to 7 reference is made to the description of the embodiment of

[0053] which can be applied mutatis mutandis.

[0054] In both embodiments, the wedge-shaped recess 40 may preferably adopt at least one of the following thread parameters:

[0055] ·w groove / p tr = 0.5 to 0.95 (the ratio of the width of the wedge-shaped recess 40 in the axial direction to the pitch of the thread 30)

[0056] ·w offset / ptr = 0.1 to 0.5 (ratio of the width of the buffer 49 in the axial direction to the pitch of the thread 30)

[0057] · The taper angle α of the wedge-shaped side surface 44 = 5° to 30°

[0058] · d r / d c = 0.6 to 1.1 (ratio of the diameter of the ridge 46 to the core diameter of the thread 30)

[0059] · The number of ridges 46 per turn of the wedge-shaped groove 40: at least one per turn, preferably two or more ridges 46 per turn.

Claims

1. A screw, comprising: - a shank (10), wherein the shank (10) has a tip (11), a rear end (18), and a longitudinal axis (99) extending through the tip (11) and through the rear end (18), wherein the tip (11) and the rear end (18) are opposite ends of the shank (10); and - a thread (30) connected to the shank (10) and wound around the shank (10), - wherein a wedge-shaped groove (40) is provided in the shank (10), the wedge-shaped groove (40) being wound around the shank (10) and extending alongside at least one section of the thread (30), wherein the wedge-shaped groove (40) is defined by wedge-shaped sides (44) that taper rearwardly for wedging into a grout shell surrounding the shank (10), characterized in that at least one ridge (46) is provided in the wedge-shaped groove (40), wherein the ridge (46) separates the wedge-shaped groove (40).

2. The screw according to claim 1, characterized in that the ridge (46) extends parallel to the longitudinal axis (99).

3. The screw according to any one of the preceding claims, characterized in that the ridge (46) projects from the wedge-shaped side (44).

4. The screw according to any one of claims 1 to 2, characterized in that the ridge (46) is recessed into the wedge-shaped groove (40) or flush with its surroundings.

5. The screw according to any one of claims 1 to 2, characterized in that a plurality of ridges (46) are provided in the wedge-shaped groove (40), wherein the ridges (46) separate the wedge-shaped groove (40).

6. The screw according to claim 5, characterized in that each turn of the wedge-shaped groove (40) is provided with at least one ridge (46).

7. The screw according to any one of claims 1 to 2, characterized in that the screw is a concrete screw, and / or In at least some regions of the thread (30), the ratio of the maximum outside thread diameter (d tr ) of the thread (30) to the pitch (p tr ) of the thread (30) is between 1 and 2.

8. The screw according to claim 7, characterized in that In at least some regions of the thread (30), the ratio of the maximum outside thread diameter (d tr ) of the thread (30) to the pitch (p tr ) of the thread (30) is between 1.2 and 1.6.

Images