Expanding anchor

Abstract

The invention relates to an expansion anchor (1) for anchoring in concrete, having a shaft (2) made of metal, which extends along a longitudinal axis (L). At an expansion section (13) there is arranged an expansion sleeve (12) made of metal, wherein the expansion sleeve has a radially outwardly projecting press (18). According to the invention, the press (18) is designed such that a connection straight line (28) perpendicular to the longitudinal axis (L) runs from a tip (27) of the press (18) towards an angular point (29) of a bottom surface (23) of the press (18).

Description

Technical Field

[0001] This invention relates to an expansion anchor having an anchor shank made of metal extending along a longitudinal axis and having a load-introducing device at a rear and an expansion section at a front, wherein an expansion sleeve made of metal is arranged at the expansion section, wherein the expansion sleeve surrounds the anchor shank in the circumferential direction and is movable forward relative to the anchor shank along the longitudinal axis, wherein the expansion sleeve has a base, and a pressing portion protruding radially outward from the base is integrally arranged at the base, the pressing portion having a bottom surface, a plurality of side surfaces and exactly one tip, wherein the bottom surface faces the base, the side surfaces connect the bottom surface to the tip, and the tip protrudes radially outward from the base and forms the outermost radial point and the rear end of the pressing portion. Background Technology

[0002] European patent application EP 1 314 897 A2 discloses an expansion anchor according to this class. The expansion anchor—so-called a bolt anchor—comprises a pin-shaped shank with external threads arranged at the rear of the shank as a load-introducing device. The expansion anchor has an expansion region at its front, which has an expansion section of the shank at which an expansion sleeve is arranged. An expansion cone is located at the front of the expansion section and can be pulled into the expansion sleeve, thereby expanding the expansion sleeve and pressing it against the wall of the borehole, into which the expansion region is introduced to anchor the expansion plug. For anchoring, the expansion sleeve must be expanded by the return movement of the shank. To achieve expansion, the expansion sleeve must be held fixedly in the borehole such that it does not, or at least not to the same extent, move out of the borehole with the expansion cone during the return movement of the shank, as this would impede expansion, by which the return movement pulls the expansion cone for expansion into the expansion sleeve. To ensure that the expansion sleeve is held in the drill hole before actual expansion, known expansion anchors have a pyramidal pressing portion that protrudes radially outward from the cylindrical and slotted base of the expansion sleeve. The pressing portion has a tip at its rear end, which engages with the wall of the drill hole and thus holds the expansion sleeve in a fixed position within the hole. However, when the expansion anchor is wedged into the drill hole, the tip wears down due to friction against the hole wall. This results in the tip no longer being present after wedging, and the outwardly rounded pyramid, due to friction, can no longer hold the expansion sleeve in the drill hole during the anchor shank's return motion, thus preventing the expansion sleeve from expanding as planned. Summary of the Invention

[0003] Therefore, the objective of this invention is to improve a known expansion anchor in such a way that the expansion anchor is reliably ensured to expand as planned.

[0004] According to the invention, this task is solved by an expansion anchor having the following features: the pressing portion is designed such that a connecting line perpendicular to the longitudinal axis extends from the tip through a corner of the bottom surface to the longitudinal axis, and the corner is the intersection of the two sides with the bottom surface. The expansion anchor for anchoring in concrete according to the invention has a metal shank extending along the longitudinal axis. The shank has a pin-like basic shape, i.e., its length is several times larger than its diameter, or—when the cross-section of the shank is not circular—several times larger than the diameter of the circle of the cross-section of the outer shank. A load-introducing device, particularly an external or internal thread, is provided at the rear of the shank, by which a load can be transferred from an attachment fastened to the expansion anchor at the bottom of the anchorage. At the front, the shank has an expansion section in which an expansion sleeve made of metal is arranged. "Front" and "rear" refer to the introduction direction in the drill hole into the bottom of the anchorage. The anchor base, such as the ceiling or wall of a building, is especially made of concrete. An expansion section and expansion sleeve form the expansion area of ​​the expansion anchor, which allows the anchor to be anchored in the anchor base so that the load can be transferred from the attachment through the expansion anchor to the anchor base. For anchoring, the expansion anchor is inserted or wedged into the drill hole with the expansion area forward along the insertion direction, wherein the expansion sleeve is tensioned against the drill hole wall and surrounds the anchor shank in the expansion section circumferentially. "Surrounding" here does not necessarily mean completely surrounding, but rather holding the expansion sleeve at the anchor shank in a manner that prevents loss but allows for longitudinal forward movement. For reliable anchoring in the drill hole, the expansion sleeve must additionally be expanded. For this purpose, the expansion sleeve can be moved forward relative to the anchor shank along the longitudinal axis, so that the expansion element of the expansion section reaches into the expansion sleeve and radially separates and expands the expansion sleeve, which is particularly designed to be wedge-shaped and expands diametrically in the insertion direction. For this purpose, the expansion sleeve has a slit, particularly at its front end, which divides the base of the expansion sleeve, especially a hollow cylindrical shape, into individual expansion arms in the front section. The base does not necessarily form a closed cylinder. The base can be made from flat sheet metal, particularly by stamping, shaping, and / or bending, and has a continuous slit in the longitudinal direction.

[0005] After the expansion region of the expansion anchor according to the invention is inserted into the drill hole and the expansion sleeve is tensioned against the drill hole wall, the anchor shank is pulled backward against the insertion direction to allow expansion. This draws the expansion element, such as an expansion cone, into the expansion sleeve, and the expansion sleeve expands, inflates, and is further tensioned against the drill hole wall. The return movement of the anchor shank relative to the expansion sleeve corresponds to the forward relative movement of the expansion sleeve relative to the anchor shank. A radially outwardly protruding pressing portion is integrally arranged in the base so that the expansion sleeve tensioned in the drill hole expands during the return movement of the anchor shank and does not move backward out of the drill hole due to the return movement of the expansion element. The pressing portion is used to increase friction with and / or for engagement with the drill hole wall, which increases the holding force of the expansion sleeve in the drill hole. The pressing portion itself has a real or imaginary bottom surface, side surface, and tip, with the bottom surface facing the base. The bottom surface rests planarly against the outer side surface of the base. The bottom surface geometrically forms a transition from the pressing portion to the base. The tip of the pressed portion protrudes radially outward from the base and forms the outermost radial point of the pressed portion. Furthermore, the tip is arranged at the pressed portion such that it, alone or together with other points, edges, or surfaces, forms the rear end of the pressed portion. The bottom surface and the tip are connected to each other by at least one side surface, which intersects the bottom surface in a bottom edge. The pressed portion can also have multiple side surfaces, each of which intersects the bottom surface with a bottom edge.

[0006] The pressing section need not be solid. It is made, in particular, by pressing the substrate, i.e., by partially pressing it into the substrate material, without creating seams or openings. Specifically, the substrate is made of circumferentially curved slats, and the pressing section is pressed radially outward from these slats, which are particularly outwardly arched. That is, the pressing section is, in particular, an arched section, in which the substrate material is radially compressed outward, but not removed from the substrate. The outwardly compressed material forms the pressing section, which geometrically protrudes radially above the substrate. Such a pressing section exhibits high resistance to radial compression when the expansion sleeve is inserted into the drill hole.

[0007] The expansion anchor according to the invention is characterized by a design of the pressing portion such that a connecting line perpendicular to the longitudinal axis extends through the tip, and the longitudinal axis extends through the corner point of the bottom surface. Thus, the connecting line forms a perpendicular line relative to the longitudinal axis passing through the tip, wherein the deviation of the connecting line from a theoretically precise perpendicular line is within a few degrees of manufacturing tolerance. A "corner point" is any point on the bottom edge. If the pressing portion has multiple sides, the corner point is specifically the intersection of two sides with the bottom surface. The corner point, together with the tip, forms the rear end of the pressing portion. The advantage of such a pressing portion is that even if the original tip of the pressing portion is worn when the expansion area of ​​the expansion anchor is wedged into the drill hole, an additional tip is formed by a rearward-pointing edge extending radially relative to the longitudinal axis between the corner point and the tip, located on the connecting line. The radially outer point of this edge then serves as the tip, which prevents the expansion sleeve from moving rearward out of the drill hole when the opening is complete.

[0008] According to the invention, exactly one pressing portion can be provided at the expansion sleeve. In particular, the expansion sleeve has at least two, and especially at least three pressing portions, which are arranged in a manner uniformly distributed in the circumferential direction. If expansion arms separated by slits are provided at the expansion sleeve, then, in particular, a pressing portion can be provided at each of the expansion arms. In particular, the pressing portion is not arranged at the front of the expansion sleeve, and it does not form the front end of the expansion sleeve. Instead, the pressing portion can be arranged at the rear end of the expansion sleeve, wherein, preferably, the pressing portion is arranged such that its bottom surface is completely surrounded by the side surface of the substrate. Thus, the pressing portion neither forms the front end nor the rear end of the expansion sleeve. The pressing portion can be implemented, in particular, in a pyramidal shape, for example, as a tetrahedron with a flat triangular surface, wherein the sides can also be spatially arched.

[0009] The pressing section rises radially from the bottom surface toward the tip, particularly against the introduction direction along the longitudinal axis, and more specifically from the bottom edge forming the transition section leading to the pressing section. Here, the rise can also be discontinuous, for example, in multiple sections. Therefore, the pressing section forms a wedge shape, which facilitates the insertion of the expansion sleeve into the drill hole along the introduction direction. However, a ridge constructed at the rear end of the pressing section, extending between the corner and the tip, hinders its removal from the drill hole.

[0010] In a preferred embodiment of the expansion anchor according to the invention, at least one side of the pressing portion extends circumferentially, thereby forming a rear side of the pressing portion. This rear side includes the tip of the pressing portion. This side forming the rear side is particularly located in a radial plane relative to the longitudinal axis, i.e., it extends purely circumferentially. Preferably, in this configuration, the rear side rises radially from the bottom surface toward the tip in a clockwise direction about the longitudinal axis when viewed from the rear, wherein the rise can also be discontinuous. Thus, the pressing portion also forms a wedge shape in the circumferential direction, which prevents the expansion sleeve from rotating when—as is common in the case of bolt anchors—the anchor shank is returned from the drill hole by rotating the nut onto the external thread used as a load-introducing device.

[0011] Preferably, the pressing portion of the expansion anchor according to the invention has at least two intersecting sides, the intersecting edges of which include pointed ends. These two sides form an angle between 60 and 120 degrees, particularly between 80 and 100 degrees. In particular, the sides form an angle of approximately 90 degrees. Therefore, the sides also form a wedge shape that prevents the expansion sleeve from moving out of the drill hole.

[0012] Preferably, the two side surfaces are arranged orthogonally to the side surfaces of the substrate. "Orthogonal to the side surfaces of the substrate" means that at each intersection of the substrate and the side surfaces, the surface normal of the substrate lies in a tangential plane relative to the side surface. In particular, the tangential plane is a radial plane and / or an axial plane, especially if one of the tangential planes is radial and the other is axial. This configuration of the side surfaces results in a large resistance to pull-out of the expansion sleeve from the drill hole.

[0013] In another preferred configuration of the expansion sleeve according to the invention, the two side faces rearward. This means that, in a top view, the two side faces project visiblely from the rear along the insertion direction above the base of the expansion sleeve. In other words, the vector of the surface normals of these side faces has a component parallel to the longitudinal axis and against the insertion direction. Preferably, in this configuration, the two side faces are inclined relative to the longitudinal axis. This means that when the surface normals of the side faces are projected onto the axial plane of the longitudinal axis, the projection of the surface normals is inclined relative to the longitudinal axis, which lies in said axial plane. Here, the inclination angles of the two side faces relative to the longitudinal axis are preferably the same. Here, each inclination angle is between 30 degrees and 60 degrees, thereby creating a wedge shape on the side faces against the pull-out direction from the drill hole.

[0014] Another preferred feature is that the two sides are symmetrical about the axial plane with respect to the longitudinal axis, which facilitates the manufacturing of the pressed part.

[0015] Preferably, the bottom edges of the bottom surface extend not in a straight line, but rather in an arc shape. Specifically, the pressing section has three bottom edges, of which two extend in a straight line and the third extends in an arc shape. In this case, the two straight bottom edges are flat side surfaces, extending particularly orthogonally to the side surface of the substrate, and their intersection forms a corner point, which, together with the tip, lies on a connecting line perpendicular to the longitudinal axis. Conversely, the arc-shaped bottom edges are oriented forward, particularly along the introduction direction, and the associated side surface rises radially from the bottom edges toward the tip against the introduction direction; this associated side surface can also be referred to as a "wedge surface" or "inclined surface." The angle between the side surface and the wedge surface or inclined surface is at most 30 degrees. This configuration has proven particularly advantageous because, compared to pressing sections disclosed in the prior art, this configuration does not increase or only slightly increases the introduction resistance of the expansion sleeve into the drill hole, but significantly improves the resistance of the expansion sleeve to being pulled out of the drill hole. Attached Figure Description

[0016] The features and combinations of features, embodiments, and configurations of the present invention mentioned above in the specification, as well as the features and combinations of features mentioned and / or drawn in the accompanying drawings, can be used not only in the corresponding given or drawn combinations, but also in virtually any other combination or individually. Embodiments of the present invention may not have all the features of a dependent claim. A single feature of a claim may also be replaced by another disclosed feature or combination of features. It is possible for the present invention to have, in principle, any portion of the features of an embodiment but not all the features of the embodiments, in combination with one, several, or all the features of another embodiment, if necessary.

[0017] The invention will now be described in more detail with reference to the accompanying drawings, which show:

[0018] Figure 1 A side view of the first expansion anchor according to the present invention;

[0019] Figure 2 In relative to Figure 1 An enlarged schematic diagram of the expansion region of the first expansion anchor according to the present invention in a side view rotated 90° about the longitudinal axis;

[0020] Figure 3 A top view of the unfolded expansion sleeve of the first expansion anchor according to the present invention;

[0021] Figure 4 A top view of the unfolded diagram of an alternative expansion sleeve for an expansion anchor according to the invention; and

[0022] Figure 5 Figure 4A schematic cross-sectional view of the expansion arm of the alternative expansion sleeve along section line VV. Detailed Implementation

[0023] Figure 1 The diagram shows a first expansion anchor 1 according to the invention for anchoring into the bottom of an anchorage made of concrete. The expansion anchor 1 includes an anchor shank 2 made of metal, which extends along a longitudinal axis L from a rear end 3 along an introduction direction E that leads the expansion anchor 1 into a drilled hole in the bottom of the anchorage (not shown) to a front end 4. The rear end 3 of the expansion anchor 1 forms the striking face of a hammer bolt 5, with an external thread 6 abutting the hammer bolt as a load-introducing device 7. A nut 8 is screwed onto the external thread 6, and a washer 9 is tightened against the bottom of the anchorage by means of this nut against an attachment (not shown). Along the introduction direction E, a threadless spacing section 10 abuts the external thread 6, having a flange 11 that forms a stop for an expansion sleeve 12. Anterior to the flange 11 along the introduction direction E, the anchor shank 2 has an expansion section 13 in which the expansion sleeve 12 circumferentially surrounds a neck section of the anchor shank 2, the diameter of which decreases. The expansion sleeve 12 is protected from loss by the surrounding structure, but is movable forward relative to the anchor shank 2 along the longitudinal axis L toward the expansion cone 15, which serves as the expansion element 14. The expansion sleeve 12 has two slots 16 that extend longitudinally from the front end of the expansion sleeve 12 and end in the bore 19 at the rear, dividing the front two-thirds of the expansion sleeve 12 into three expansion arms 17 that are radially outwardly compressed to expand when the expansion sleeve 12 is fitted onto the expansion cone 15. Figure 3 The distribution of seam 16 and expansion arm 17 can be clearly seen in the image. Figure 3 The diagram shows a flat, unfolded view of the expansion sleeve 12, or rather, the expansion sleeve 12 before it is bent around the neck section of the anchor shank 2.

[0024] Each of the expansion arms 17 has a punched portion 18 so that the expansion sleeve 12 finds a fixed fulcrum in the drill hole after the expansion section 13 of the expansion anchor 1 is inserted into the drill hole and before expansion, thereby allowing the expansion sleeve 12 to expand by moving the anchor shank 2 against the introduction direction E by tightening the nut 8. The punched portion 18 protrudes radially outward from the base 20 of the expansion sleeve 12. The base 20 is formed of a flat, undeformed strip, from which the expansion sleeve 12 is made. In the unexpanded state of the expansion anchor 1, as... Figure 1 and 2 As shown, the substrate 20 has a cylindrical side surface 21, which is located on... Figure 3The unfolded diagram has a flat rectangular surface 22. The stamped portions 18 arranged on the base 20 each have an imaginary bottom surface 23, three side surfaces 24, 25, 26, and a tip 27. The bottom surface 23 faces and abuts the base 20. The bottom surface 23 forms the dividing surface between the stamped portion 18 and the side surface 21 of the base 20 purely in terms of geometry. The three side surfaces 24, 25, 26 connect the bottom surface 23 to the tip 27. Each of the tips 27 of the three stamped portions 18 of the expansion sleeve 12 protrudes radially outward from the base 20, forming the outermost radial point and the corresponding rear end of the stamped portion 18. Here, the stamped portions 18 are designed such that a connecting straight line 28 perpendicular to the longitudinal axis L extends from the corresponding tip 27 through the corner point 29 of the bottom surface 23 to the longitudinal axis L. Figure 2 Between corner point 29 and tip 27, a connecting line 28 forms a cut edge 30 between the first side surface 24 and the second side surface 25. This cut edge 30, together with tip 27, forms the corresponding rear end of the stamped portion 18. The two side surfaces 24 and 25 extend orthogonally to, i.e., perpendicularly to, the side surface 21 of the base 20. They both rise radially from the bottom surface 23 toward the tip 27, face rearward, and are of the same size. The first side surface 24 and the second side surface 25 are inclined at inclination angles α1 and α2 of 45° relative to the longitudinal axis L, respectively. Figure 1 As shown. Therefore, the two side surfaces 24 and 25 are symmetrical with respect to the axial plane of the longitudinal axis L. The third side surface 26 is... Figure 3 The unfolded top view has a fan-shaped shape, with corner point 29 forming the center point of the fan. Therefore, the junction of the third side surface 26 and the bottom surface 23 forms the bottom edge 31, which extends in an arc rather than a straight line, extending in the form of an arc in the unfolded view.

[0025] If the expansion sleeve 12 is introduced into the drill hole, the tip 27 engages with the drill hole wall and holds the expansion sleeve 12 within the drill hole. Since the stamped portion 18 is stamped out of the base 20 rather than pressed out, the stamped portion is constructed to be more stable and can be compressed less radially than a molded and bent cantilevered wing. Because the tip 27 and the intersecting edge 30 form the rear end of each stamped portion 18, the tip 27 is protected from deformation due to friction at the drill hole wall during insertion. However, even if the tip 27 is worn during insertion, the outwardly and rearwardly tapering intersecting edge 30 remains engaged with the drill hole wall.

[0026] Figure 4 and 5 An alternative configuration of the expansion sleeve 12a is shown, which, except for the stamped portion 18a, is... Figures 1 to 3The expansion sleeve 12 is the same as that described above. To avoid repetition, only the stamped portion 18a will be discussed below. In the top view of the unfolded diagram, the stamped portion 18a is also fan-shaped, and the external geometry of this fan is the same as that of the stamped portion 18 described above, but rotated 45° relative to the longitudinal axis L compared to the stamped portion 18 described above. Due to this rotation, the second side 25a is parallel to the longitudinal axis L, and the first side 24a extends in the circumferential direction. The first side 24a forms the rear side of the stamped portion 18a, which here faces rearward as the only side 24a. This first side is viewed from the rear along the introduction direction E and rises radially toward the tip 27 from the bottom surface 23 in a clockwise direction about the longitudinal axis L.

[0027] In both configurations of the expansion sleeves 12 and 12a, the side surfaces 26 and 26a of the stamped portions 18 and 18a form wedge-shaped surfaces that rise radially backward. This facilitates insertion into the drill hole. The radially outer ends of the tips 27 and 27a, or the intersecting edges 30 and 30a, reliably hold the expansion sleeves 12 and 12a for expansion in the drill hole and prevent the expansion sleeves 12 and 12a from moving out of the drill hole along with the expansion cone 15 during expansion.

[0028] List of reference numerals

[0029] 1. Inflatable Anchor

[0030] 2 Anchor handle

[0031] 3. Rear end of expansion anchor 1

[0032] 4. Front end of expansion anchor 1

[0033] 5 hammer bolt

[0034] 6 External threads

[0035] 7. Load introduction device

[0036] 8 nuts

[0037] 9 gaskets

[0038] 10 Spacing Sections

[0039] 11 Flange

[0040] 12, 12a Expansion Sleeve

[0041] 13 Expansion Section

[0042] 14 Expansion element

[0043] 15. Expansion Cone

[0044] 16 seams

[0045] 17. Expansion Arm

[0046] 18, 18a Pressing Section

[0047] 19 Drilling

[0048] 20 matrix

[0049] 21 Side surfaces

[0050] 22 Rectangular face

[0051] 23, 23a Bottom surface

[0052] 24, 24a First side view

[0053] 25, 25a Second side

[0054] 26, 26a Third side

[0055] 27, 27a Tip

[0056] 28. Connect the straight lines

[0057] Corner points 29 and 29a

[0058] 30, 30a Intersecting edges

[0059] 31, 31a Bottom edge

[0060] E Introduction Direction

[0061] L longitudinal axis

[0062] α1 Inclination angle of the first side surface 24

[0063] α2 The tilt angle of the second side surface is 25°.

Claims

1. An expansion anchor (1) for anchoring in concrete, having an anchor shank (2) made of metal extending along a longitudinal axis (L), and having a load-introducing device (7) at the rear and an expansion section (13) at the front, wherein, An expansion sleeve (12, 12a) made of metal is arranged at the expansion section (13), wherein the expansion sleeve (12, 12a) surrounds the anchor shank (2) in the circumferential direction and is movable forward relative to the anchor shank (2) along the longitudinal axis (L), wherein the expansion sleeve (12, 12a) has a base (20), and pressing portions (18, 18a) protruding radially outward from the base (20) are integrally arranged at the base, the pressing portions having a bottom surface (23, 23a) and multiple sides The base (23, 23a) has two sides (24, 24a, 25, 25a, 26, 26a) and a tip (27, 27a), wherein the bottom surface (23, 23a) faces the base (20), the side surface (24, 24a, 25, 25a, 26, 26a) connects the bottom surface (23, 23a) to the tip (27, 27a), the tip (27, 27a) protrudes radially outward from the base (20) and forms the outermost radial point and the rear end of the pressing part (18, 18a). Its features are, The pressing part (18, 18a) is designed such that the connecting straight line (28) perpendicular to the longitudinal axis (L) extends from the tip (27, 27a) through the corner point (29, 29a) of the bottom surface (23, 23a) to the longitudinal axis (L), and the corner point (29, 29a) is the intersection of the two side surfaces (24, 24a, 25, 25a, 26, 26a) and the bottom surface (23, 23a).

2. The expansion anchor according to claim 1, characterized in that, The side (24a) of the pressing part (18a) extends in the circumferential direction and forms the rear side of the pressing part (18a), the pressing part including the tip (27a).

3. The expansion anchor according to claim 2, characterized in that, The side (24a) is viewed from the rear and rises radially in a clockwise direction from the bottom (23a) toward the tip (27a) about the longitudinal axis (L).

4. The expansion anchor according to any one of the preceding claims, characterized in that, The pressing part (18, 18a) has at least two intersecting side surfaces (24, 24a, 25, 25a), and the intersecting edge (30, 30a) of the side surfaces includes the tip (27, 27a).

5. The expansion anchor according to claim 4, characterized in that, The two sides (24, 24a, 25, 25a) are arranged orthogonally to the side surface (21) of the substrate (20).

6. The expansion anchor according to claim 4, characterized in that, The two sides (24, 25) face backward.

7. The expansion anchor according to claim 4, characterized in that, The two sides (24, 25) are inclined relative to the longitudinal axis (L).

8. The expansion anchor according to claim 7, characterized in that, The two sides (24, 25) have the same tilt angle (α1, α2).

9. The expansion anchor according to claim 4, characterized in that, The two sides (24, 25) are symmetrical with respect to the axial plane of the longitudinal axis (L).

10. The expansion anchor according to any one of claims 1 to 3, characterized in that, The bottom edges (31, 31a) of the bottom surfaces (23, 23a) do not extend in a straight line.

11. The expansion anchor according to claim 10, characterized in that, The bottom edges (31, 31a) of the bottom surface (23, 23a) extend in an arc shape.

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