Anchoring element for anchoring in a drilled hole in a material

Description

[0001] The invention relates to an anchoring element for anchoring in a borehole in a material, in particular in a hard material and in particular concrete.

[0002] DE 20 2006 021 070 U1 discloses a fastening anchor for screwing into a borehole and an arrangement with such a fastening anchor.

[0003] DE 297 11 128 U1 relates to a self-drilling and thread-forming fastener.

[0004] Anchoring elements for anchoring in a drilled hole in concrete have a core with a cutting thread formed thereon, with which the anchoring element can be screwed directly into the drilled hole. The torque required for screwing in is introduced via a torque transmission element of the anchoring element. High screwing torques are particularly necessary when screwing the anchoring element into a hard material. The torque transmission element can be formed on a countersunk head. The countersunk head protrudes from the material on the outside of the drilled hole and creates an unevenness. This unevenness is undesirable because it leads to impairments and poses a risk of injury and / or damage.

[0005] The invention is based on the object of improving the anchoring of an anchoring element in a borehole in a material, in particular a hard material, and in particular of ensuring the surface-flush arrangement of the anchoring element.

[0006] This object is achieved by an anchoring element having the features of claim 1.

[0007] The core of the invention is that the anchoring element has at least one projection on a conical outer surface of a countersunk head. The projection protrudes from the conical outer surface.

[0008] When the anchoring element is screwed into a borehole in a material, particularly a hard material, particularly concrete, the projection rubs against the circular borehole edge on the front side. As the screwing depth of the anchoring element increases, the at least one projection creates a depression extending from the surface of the material, which in particular corresponds to the contour of the countersunk head, is in particular conical, and is in particular designed to receive, in particular to completely receive, the countersunk head.

[0009] The at least one projection is in particular designed like a longitudinal web and extends in particular along a linear web axis, which runs in particular in a plane containing a central longitudinal axis of the anchoring element, in particular a cylindrical core of the anchoring element. The at least one projection has a projection length that is oriented along the central longitudinal axis and corresponds to at least 50% of the longitudinal extent of the countersunk head, in particular at least 60%, in particular at least 70%, in particular at least 80%, in particular at least 90% and in particular 100%. The at least one projection has a raised geometry relative to the conical outer surface. The geometry of the at least one projection is in particular pyramid-shaped, with a polygonal, in particular quadrangular, in particular rectangular and in particular square, base area and in particular triangular pyramid side surfaces.In particular, two opposite pyramid side surfaces are identical.

[0010] The at least one projection can also have a non-linear, in particular curved, course.

[0011] The protruding projection scrapes off the material at the edge of the drill hole when screwing in the anchoring element, allowing the anchoring element to be completely recessed into the material, including the countersunk head. This ensures that the anchoring element is positioned at least flush with the surface of the material. The countersunk head of the anchoring element does not protrude from any surface of the material and can, in particular, be recessed from the surface of the material.

[0012] It was found that the anchoring element with the countersunk head can be screwed flush with the material surface without exerting excessive pressure on the borehole edge. Excessive pressure on the borehole edge could lead to material spalling and thus to an uncontrolled and undesirable enlargement of the borehole surface.

[0013] The at least one projection is attached in one piece to the outer surface of the countersunk head and is formed in one piece, in particular by means of extrusion, during the pressing of the countersunk head.

[0014] The anchoring element is, in particular, a concrete screw. The anchoring element is made of a metallic material, in particular a steel material, which is, in particular, galvanized and / or zinc-flake coated. In particular, the anchoring element is made of a material designated 1.4401, 1.4404, 1.4571, 1.4578, and / or 1.4529. Other metallic materials, in particular steel, are also possible.

[0015] The anchoring element has the cylindrical core with an insertion end, an outer end opposite the latter, and a screw-in direction oriented from the outer end to the insertion end. A cutting thread is formed integrally with the core and extends along a cutting thread section from the insertion end. In particular, the cutting thread section is designed as a solid cross-section. This increases the stability of the anchoring element. The cutting thread is, in particular, an external thread and is, in particular, rolled onto the core. The cutting thread can have cutting elements that simplify screwing the anchoring element into the borehole. Such cutting elements are arranged directly on the cutting thread, for example, rolled onto it or welded thereto. The cutting elements protrude, in particular, in the radial direction on the cutting thread.

[0016] The anchoring element has a fastening thread, which is designed in particular as an internal thread and in particular as a metric internal thread. The fastening thread is open to the outside, opposite to the screwing direction, and enables detachable fastening, in particular the screwing in of a fastening element, in particular a fastening screw.

[0017] A torque transmission means is arranged on the anchoring element and is particularly integrated into the core. The torque transmission means serves to transmit a driving torque from a tool to the core. The driving torque is required to drive the anchoring element into the borehole. The torque transmission means is arranged particularly in the region of the countersunk head and is particularly integrated into the countersunk head. Due to the design of the anchoring element with a countersunk head, the anchoring element has an enlarged head diameter, at which a maximum inner diameter of the torque transmission means is arranged.

[0018] The anchoring element enables a simple and robust design of the projection on the outer surface. The at least one projection has a projection depth that can be varied in the screwing direction and ensures improved scraping of the inner wall of the borehole when screwing in the anchoring element. In particular, the projection depth has a maximum along the screwing direction. In particular, the projection depth has a linear profile along the screwing direction, starting from the end surfaces of the countersunk head. In particular, the anchoring element has a radius in a plane perpendicular to the central longitudinal axis at the maximum of the projection depth that corresponds to half the diameter of the outer surface of the countersunk head. This ensures that the countersunk head is countersunk in the area of ​​the material scraped out by the projection.

[0019] An anchoring element according to claim 2 has an improved scraping effect. It is ensured that the drill hole is sufficiently scraped to arrange the countersunk head flush with the material. The recess scraped out with the projections has a volume that is larger than that of the countersunk head. The countersunk head can be reliably arranged completely within the recess. The anchoring element has in particular three and in particular exactly three projections. More than three, in particular four, five, six or seven or more projections can also be arranged. The projections are arranged in particular evenly spaced from one another in the circumferential direction of the central longitudinal axis. It has been found that, on the one hand, the more projections are provided, the better the effectiveness of material removal by means of the projections.In particular, it was recognized that the scraping of the material surface must occur at approximately one revolution. Furthermore, the number of projections cannot be chosen arbitrarily large, to avoid a continuous outer contour being formed by a large number of projections in the circumferential direction, which would result in a reduced scraping effect.

[0020] An anchoring element according to claim 3 has an improved scratching effect. A leading flank and a trailing flank enable improved screwing in of the anchoring element. The leading flank is the flank surface that runs forward when the anchoring element is screwed into the material, i.e., the one that first comes into contact with the material. The trailing flank is the flank surface that runs backward in the screwing direction, i.e., is located in the shadow of the projection.

[0021] A leading flank angle according to claim 4 enables different force effects. The leading flank angle can be selected to be comparatively small, in particular between 0° and 15°. With such a configuration, the projection is designed in the manner of a chisel, which enables improved material removal from the borehole's inner wall. The leading flank angle can also be negative.

[0022] It is also possible for the leading flank angle to be larger, particularly between 20° and 45°, and especially 30°. Such a projection exhibits particularly high stability.

[0023] An anchoring element according to claim 5 with a trailing flank angle between 20° and 45°, in particular between 25° and 35°, and in particular 30°, is robustly designed. The trailing flank provides the anchoring element with increased stability. If the trailing flank angle is identical to the leading flank angle, i.e., the projection has symmetrical flanks, the production of the projection is simplified.

[0024] An anchoring element according to claim 6 is particularly robust and allows for space-saving integration of the torque transmission means into the anchoring element. A non-circular inner contour of the torque transmission means can, for example, be a polygonal contour, in particular an internal square or internal hexagon contour. The inner contour can also be designed as a hexalobular socket contour.

[0025] An anchoring element according to claim 7 enables direct accessibility to the torque transmission means. Handling of the anchoring element is thereby simplified. The anchoring element has a robust and compact design. In particular, the fastening thread has a thread diameter that is smaller than the inside diameter of the torque transmission means. The fastening element can be pushed through the torque transmission means and screwed into the fastening thread.

[0026] An anchoring element according to claim 8 enables reliable fastening of an object to the fastening thread. The fastening thread ensures a sufficient thread depth to reliably screw the fastening element.

[0027] An anchoring element according to claim 9 enables a sufficient overall length of the anchoring element. In particular, the fastening thread is arranged along the central longitudinal axis at least partially in the countersunk head and / or in the shaft portion.

[0028] An anchoring element according to claim 10 enables increased drive.

[0029] An anchoring element according to claim 11 enables a reliable and robust fastening of the fastening element.

[0030] Both the features specified in the patent claims and the features specified in the exemplary embodiments of anchoring elements according to the invention are suitable, either individually or in combination with one another, for further developing the subject matter of the invention. The respective combinations of features do not represent any limitation with regard to further developments of the subject matter of the invention, but are essentially merely exemplary in nature.

[0031] Further features, advantages, and details of the invention will become apparent from the following description of exemplary embodiments with reference to the drawings. They show: Fig. 1 a side view of an anchoring element according to the invention with symmetrically designed projections on the countersunk head, Fig. 2 a longitudinal section according to section line II-II in Fig. 1 , Fig. 3 a view according to arrow III in Fig. 1 , Fig. 4 a sectional view according to section line IV-IV in Fig. 1 , Fig. 5a Fig. 1 corresponding side view of an anchoring element according to a further embodiment, Fig. 6 a sectional view according to section line VI-VI in Fig. 5 .

[0032] One in Fig. 1 bis 4 Anchoring element marked with 1 is used for anchoring in a borehole in a material, in particular in a hard material, in particular concrete.

[0033] The anchoring element 1 is in particular a concrete screw, in particular a concrete dowel.

[0034] The anchoring element 1 has a cylindrical core 2 with an insertion end 3 and an oppositely arranged outer end 4. A screw-in direction 5 is defined from the outer end 4 to the insertion end 3. A central longitudinal axis 6 of the core 2 is oriented parallel to the screw-in direction 5. The anchoring element 1 has a total length L total directed along the central longitudinal axis 6.

[0035] A cutting thread section AG extends from the inlet end 3 along the central longitudinal axis 6. A cutting thread 7 extends from the inlet end 3 along the cutting thread section AG. The cutting thread 7 is designed such that the anchoring element 1 can be screwed directly into the material in the borehole. The cutting thread 7 cuts a thread spiral directly into an inner wall of the borehole. The cutting thread 7 can have cutting elements not shown in detail. The cutting thread 7 has a thread diameter DG. The cutting thread 7 is, in particular, rolled integrally onto the core 2.

[0036] The cutting thread 7 has a thread pitch H which is in particular less than 10 mm, in particular less than 8 mm and in particular between 6 mm and 7 mm.

[0037] At the inlet end 3, the core 2 has at least one axial groove 8. The axial groove 8 has a groove length LN which extends along the central longitudinal axis 6. The groove length LN is in particular at least 30% of the thread pitch H and in particular at most 200% of the thread pitch H, in particular at least 50% and at most 150% of the thread pitch H and in particular at least 70% and at most 120% of the thread pitch H. The axial groove 8 extends from a lower end face of the core 2 along a groove longitudinal axis 9. The groove longitudinal axis 9 is oriented parallel to the central longitudinal axis 6. It is particularly conceivable for the axial groove 8 to cross the cutting thread 7, i.e. in particular for the axial groove 8 to interrupt the cutting thread 7.

[0038] If multiple axial grooves 8 are provided, they are arranged circumferentially around the central longitudinal axis 6 on the outer surface of the anchoring element 1, i.e., on the outer surface of the core 2, spaced apart from one another, in particular evenly spaced in the circumferential direction. The axial grooves 8 each have a longitudinal groove axis 9 oriented parallel to the central longitudinal axis 6. The axial grooves 8 are external grooves on the outer surface of the anchoring element 1. In a plane perpendicular to the longitudinal groove axis 9, each axial groove 8 has a rectangular cross-sectional contour. The cross-sectional contour can also be designed in a different shape, in particular U-shaped or V-shaped.

[0039] The cutting thread section AG has a longitudinal extension along the central longitudinal axis 6 that is greater than the thread pitch H. In particular, the longitudinal extension of the cutting thread section AG is determined such that the cutting thread 7 has several complete thread revolutions, in particular at least three and in particular at least four complete revolutions. In particular, the longitudinal extension of the cutting thread section AG is an integer multiple of the thread pitch H.

[0040] At an end opposite the insertion end 3, the cutting thread section AG has a transition section 10. The transition section 10 is designed to taper conically in the screwing direction 5.

[0041] The cutting thread section AG is followed by a threadless shaft section A Sch, opposite to the screw-in direction 5. The shaft section A Sch is cylindrical. The shaft section A Sch has a core diameter DK that is smaller than the thread diameter DG . The longitudinal extent of the shaft section A Sch along the central longitudinal axis 6 is smaller than the longitudinal extent of the cutting thread section AG . In particular, the longitudinal extent of the shaft section A Sch approximately corresponds to the thread pitch H of the cutting thread 7.

[0042] A head section AK adjoins the shaft section A Sch, opposite the screw-in direction 5. A countersunk head 11, which forms a screw head, is arranged in the head section AK. The countersunk head 11 tapers conically in the screw-in direction 5. According to the illustrated embodiment, a cone angle k of the countersunk head 11 is 45°. The cone angle can also be smaller than 45° or larger than 45°. In particular, the cone angle k is at least 30° and at most 60°.

[0043] The head section AK has a longitudinal extension along the central longitudinal axis 6, which essentially corresponds to the longitudinal extension of the shaft section A Sch . In particular, a length LK of the head section is between 50% and 200% of a length L Sch of the shaft section L Sch , in particular between 60% and 150% and in particular between 80% and 120%.

[0044] At the transition from the shaft section A Sch to the head section AK, the countersunk head 11 has a core diameter DK. Due to the conical design, the diameter increases continuously along the head section AK up to the outer end 4. A maximum diameter D max of the countersunk head 11 is present at the outer end 4. The countersunk head 11 has a conical outer surface 12.

[0045] A plurality of projections 13 are arranged on the outer surface 12. According to the exemplary embodiment shown, three projections 13 are provided, which are equally spaced in the circumferential direction around the central longitudinal axis 6 on the outer surface 12, i.e., arranged at a distance of 120° from one another. More or fewer projections 13 can also be arranged on the outer surface 12. According to the exemplary embodiment shown, all projections 13 are identical. It is also possible for at least one of the projections 13 to be different from the others, and in particular for all projections 13 to be different from one another.

[0046] The projections 13 are each designed as webs with a web longitudinal axis 14, which is arranged on the outer surface 12. The web longitudinal axis 14 and the central longitudinal axis 6 define a radial plane, which corresponds to the plane of the drawing according to Fig. 2 corresponds.

[0047] The projections 13 are essentially pyramid-shaped with a rectangular base area arranged on the outer surface 12 of the countersunk head 11. The projections 13 have a projection depth t oriented perpendicular to the outer surface 12. The projection depth t has a maximum t max , which is located in particular at the tip of the pyramid. From the shaft section A Sch to the location of the maximum t max , the projection depth t has a linear profile. From the outer end 4 to the location of the maximum t max , the projection depth has in particular a linear profile.

[0048] In particular, the maximum t max is selected such that the countersunk head 11 has a radius r at the maximum t max of the projection depth, which corresponds to half the maximum diameter D max . In particular, the cover surface 15 of the projection 13 extending from the outer end 4 is oriented parallel to the central longitudinal axis 6. In particular, the cover surface 15 is perpendicular to the radial plane according to Fig. 2 oriented.

[0049] The projection 13 has a leading flank 16 and a trailing flank 17 relative to the circumferential direction around the central longitudinal axis 6. The leading flank 16 is located at the front during rotation of the anchoring element 1 in the screwing direction 18 and, in particular, comes into contact with the inner wall of the borehole first. The trailing flank 17 is arranged rearwardly on the projection 13 relative to the screwing direction 18, lies, so to speak, in the shadow of the projection 13, and serves, in particular, to stabilize the projection 13.

[0050] Relative to a radial direction R, the leading flank 16 is designed with a leading flank angle v of 22.5°. The leading flank angle v is designed in particular in a range from 10° to 60°, in particular 15° to 45°, and in particular 20° to 30°.

[0051] Relative to the radial direction R, the trailing flank 17 is designed with a trailing flank angle n of 22.5°. The trailing flank angle is designed in particular in a range of 10° to 60°, in particular 15° to 45°, and in particular 20° to 30°.

[0052] According to the embodiment shown, the leading flank angle v and the trailing flank angle n are identical. The projection 13 is designed symmetrically with respect to the radial direction R. The projection 13 has the contour of an isosceles triangle in a sectional plane perpendicular to the central longitudinal axis 6, as is particularly shown in Fig. 4 is shown.

[0053] In particular, the projections 13 are designed such that they do not protrude in the radial direction R relative to the maximum diameter D max.

[0054] The anchoring element 1 has a fastening thread 19, which is designed as an internal thread in a blind bore 20. The fastening thread 19 is designed as an internal thread, in particular as a metric internal thread, and has a fastening depth TB that extends along the central longitudinal axis 6 from the outer end 4 to the end of the fastening thread 19.

[0055] A fastening element, in particular a fastening screw, can be releasably attached, in particular screwed, to the fastening thread 19. The fastening thread 19 extends to the outer end 4, thus being open to the outside. The fastening thread 19 is arranged concentrically to the central longitudinal axis 6 in the anchoring element 1.

[0056] The anchoring element 1 has a torque transmission means 21, in particular an integrated one, which is designed as a frontal recess on the outer end 4. The torque transmission means 21 is a recess machined into the countersunk head 11. In a plane perpendicular to the central longitudinal axis 6, the torque transmission means 21 has a non-circular inner contour, in particular a hexalobular internal contour.

[0057] Along the screw-in direction 5, the torque transmission means 21 is arranged in front of the fastening thread 19. The torque transmission means has a clear width w oriented perpendicular to the central longitudinal axis 6. The clear width w is larger than the fastening thread diameter DB .

[0058] The torque transmission means 21 has a maximum inner diameter d Di, max , which is limited in particular by two opposing lugs of the hexalobular socket. The maximum inner diameter d Di, max is larger than the core diameter DK . The maximum inner diameter d Di, max is necessary to be able to transmit a required insertion torque to the anchoring element 1 using the tool. Accordingly, a comparatively large countersunk head 11 is required to accommodate the torque transmission means 21.

[0059] An outer end face 22 is arranged at the outer end 4. The outer end face 22 forms the outside of the anchoring element 1. The outer end face 22 is oriented perpendicular to the central longitudinal axis 6. In a flush arrangement of the anchoring element 1, the outer end face 22 is arranged flush with or below a surface of the material.

[0060] The following describes a process for screwing the anchoring element 1 into a borehole in a material, in particular concrete.

[0061] First, a drill hole is created in the material with a specific diameter. The drill hole diameter is, in particular, larger than the core diameter DK and, in particular, smaller than the thread diameter DG.

[0062] The anchoring element 1 is inserted into the borehole with the insertion end 3. A tool is attached to the torque transmission means 21, and a screwing-in rotational movement 18 is transmitted from the tool to the anchoring element 1. The rotational movement of the anchoring element 1 causes it to automatically screw into the borehole, with the cutting thread 7 cutting a thread spiral into the inner wall of the borehole. As the rotational movement increases, the anchoring element 1 is screwed into the borehole. When the anchoring element 1 reaches the surface of the material with the countersunk head 11 and the conical outer surface 12, there is initially a screwing-in resistance that prevents the anchoring element 1 from being screwed further into the borehole.

[0063] Because the projections 13 are provided on the outer surface 12, the drilled hole is scraped out with the continued rotation. In particular, the leading flanks 16 of the projections 13 remove the material surrounding the outer edge of the drilled hole. The projections 13 on the outer surface 12 of the countersunk head 11 countersink the drilled hole similar to a conical countersink drill. This makes it possible for the anchoring element 1 to be arranged flush with the surface of the material, i.e., countersunk. The anchoring element 1 does not protrude from the material in the axial direction.

[0064] In the following we refer to Fig. 5 und 6 A further embodiment is described. Structurally identical parts are given the same reference numerals as in the previous embodiment, to whose description reference is hereby made. Structurally different but functionally similar parts are given the same reference numerals with an a suffix.

[0065] One difference between the anchoring element 1a and the previous embodiment lies in the design of the projections 13a, in particular the leading flank angle v on the leading flank 16a. According to the embodiment shown, the leading flank angle v is 0°.

[0066] According to the embodiment shown, the projections 13a are each designed in a chisel-like manner. This improves, in particular increases, the material removal when screwing in the anchoring element 1a. It is advantageous if the leading flank angle is less than 15°, in particular less than 10°, and in particular less than 5°. The leading flank angle can also be negative, i.e., facing the trailing flank 17a with respect to the radial direction R. In this case, the projection 13a has a recess in the cutting plane according to Fig. 6 With a negative leading flank angle v, the projection 13a is sawtooth-shaped.

Claims

1. Anchoring element for anchoring in a borehole in a material, the anchoring element (1; 1a) comprising a. a cylindrical core (2) having i. an insertion end (3), ii. an opposite outer end (4), iii. a screw-in direction (5) orientated from the outer end (4) to the insertion end (3), iv. a central longitudinal axis (6) orientated parallel to the screw-in direction (5), b. a cutting thread (7), formed integrally with the core (2) and extending from the insertion end (3) along a cutting thread portion (AG), for screwing this into the borehole, c. a fixing thread (19), arranged in the core (2) and open outwards counter to the screw-in direction (5), for fixing a fixing element, d. a torque transmission means (21), arranged on the core (2), for transmitting a screw-in torque from a tool to the core (2), e. a countersunk head (11), which is arranged on the outer end (4) and of which the outer face (12) tapers conically along the screw-in direction (5), characterised by f. at least one projection (13; 13a) arranged on the outer face (12), the at least one projection (13; 13a) having a projection depth (t), orientated perpendicular to the outer face (12), which is variable along the screw-in direction (5).

2. Anchoring element according to claim 1, characterised by a plurality of, in particular identically configured, projections (13; 13a), arranged mutually spaced apart, in particular uniformly spaced apart, in particular in the circumferential direction of the central longitudinal axis (6).

3. Anchoring element according to any of the preceding claims, characterised in that the at least one projection (13; 13a) has a leading edge (16; 16a) and a trailing edge (17; 17a) in terms of the screw-in rotation direction (18).

4. Anchoring element according to claim 3, characterised in that the leading edge (16; 16a) is orientated at a leading edge angle (v) of -15° to 15° or of 20° to 45° to a radial direction (R) of the central longitudinal axis (6).

5. Anchoring element according to either claim 3 or claim 4, characterised in that the trailing edge (17; 17a) is orientated at a trailing edge angle (n) of 20° to 45° to a radial direction (R) of the central longitudinal axis (6).

6. Anchoring element according to any of the preceding claims, characterised in that the torque transmission means (21) is arranged concentric with the central longitudinal axis (6) and has an internal contour which is non-round in a plane perpendicular to the central longitudinal axis (6).

7. Anchoring element according to any of the preceding claims, characterised in that the torque transmission means (21) is arranged upstream from the fixing thread (19) along the screw-in direction (5).

8. Anchoring element according to any of the preceding claims, characterised in that the fixing thread (19) has a thread depth which is at least 20% of the total length (Lges) of the anchoring element (1; 1a), in particular at least 25%, in particular at least 30%, in particular at least 35%, in particular at least 40%, in particular at least 45%, in particular at least 50%, and in particular at most 90%.

9. Anchoring element according to any of the preceding claims, characterised by an unthreaded shaft portion (ASch), formed on the core (2) and arranged between the countersunk head (11) and the cutting thread portion (AG) along the screw-in direction (5).

10. Anchoring element according to any of the preceding claims, characterised in that the torque transmission means (21) has a maximum internal diameter (dDi,max) which is greater than a core diameter (DK) of the anchoring element (1; 1a).

11. Anchoring element according to any of the preceding claims, characterised in that the fixing thread (19) has a maximum internal diameter (DB) which is at least 60% of a core diameter (DK) of the anchoring element (1; 1a), in particular at least 70%, in particular at least 75%, in particular at least 80%, in particular at least 85% and in particular at most 95%.