CN112384706A

CN112384706A - Expansion anchor

Info

Publication number: CN112384706A
Application number: CN201980047038.5A
Authority: CN
Inventors: M·林加; T·希尔施勒
Original assignee: Fischerwerke GmbH and Co KG
Current assignee: Fischerwerke GmbH and Co KG
Priority date: 2018-07-13
Filing date: 2019-07-02
Publication date: 2021-02-19
Also published as: DE102018116974A1; WO2020011590A1; EP3821143A1

Abstract

The invention relates to an expansion anchor (1) for anchoring in concrete, having a shank (2) made of metal, which shank extends along a longitudinal axis (L). An expansion sleeve (12) made of metal is arranged at the expansion section (13), wherein the expansion sleeve has a press (18) which protrudes radially outward. According to the invention, the press (18) is designed in such a way that a straight connecting line (28) running perpendicular to the longitudinal axis (L) runs from the tip (27) of the press (18) through a corner point (29) of the base (23) of the press (18) towards the longitudinal axis (L).

Description

Expansion anchor

Technical Field

The present invention relates to an expansion anchor having the features of the preamble of claim 1.

Background

European patent application EP 1314897 a2 discloses an expansion anchor according to the present generic. Expansion anchors, so-called bolt anchors, comprise a pin-shaped shank with an external thread which is arranged as a load introduction device at the rear of the shank. The expansion anchor has an expansion region in the front, which has an expansion section of the shank, at which the expansion sleeve is arranged. An expansion cone is located in front of the expansion section, which expansion cone can be pulled into the expansion shell, thereby expanding the expansion shell and pressing it against the wall of the borehole into which the expansion zone is introduced for anchoring the expansion plug. For anchoring, the expansion shell must be expanded by a return movement of the shank. In order to achieve expansion, the expansion shell must be held in the borehole so firmly that it does not, or at least not to the same extent, move out of the borehole with the expansion cone when the shank undergoes a return movement, which would hinder expansion, by which the expansion cone for expansion is pulled into the expansion shell. In order to ensure that the expansion shell is held in the borehole before the actual expansion, the known expansion anchor has a pyramidal depression which projects radially outward from the cylindrical and slotted base body of the expansion shell. The hold-down parts each have a point at their rear end, with which the hold-down parts engage in the wall of the borehole and thus hold the expansion shells in place in the borehole. However, when the expansion anchor is wedged into the drill hole, the point is worn away due to friction at the wall of the drill hole, which results in that after wedging there is no longer a point, the pyramid which is rounded outwards due to friction no longer being able to hold the expansion shell in the drill hole when the anchor shank makes a return movement, so that it is not possible to expand the expansion shell as planned.

Disclosure of Invention

The object of the present invention is therefore to further develop the known expansion anchor in such a way that the planned expansion of the expansion anchor is reliably ensured.

According to the invention, this object is achieved by an expansion anchor having the features of claim 1. The expansion anchor according to the invention for anchoring in concrete has a shank made of metal, which shank extends along a 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 a circle circumscribing the cross-section of the shank. At the rear of the shank, a load introduction device, in particular an external or internal thread, is provided, with which the load can be transmitted from the attachment piece, which is fastened with the expansion anchor at the anchor bottom, to the expansion anchor. At the front, the shank has an expansion section at which an expansion sleeve made of metal is arranged. "anterior" and "posterior" refer to the direction of introduction of the expansion anchor into the borehole in the anchor base. The anchoring base, for example a ceiling or a wall of a building, is made in particular of concrete. The expansion section and the expansion sleeve form an expansion region of the expansion anchor, with which the expansion anchor can be anchored in the anchor foot in such a way that loads can be transmitted from the attachment via the expansion anchor into the anchor foot. For anchoring, the expansion anchor is inserted or wedged into the borehole with an expansion region forward in the introduction direction, wherein an expansion sleeve is tensioned against the borehole wall, which expansion sleeve surrounds the shank in the expansion section in the circumferential direction. "surrounding" does not necessarily mean completely surrounding, but merely holding the expansion shell at the shank in such a way that it is secured against loss, but can be moved forward in the longitudinal direction. In order to be reliably anchored in the borehole, the expansion shells must additionally be expanded. For this purpose, the expansion shell can be moved forward along the longitudinal axis relative to the shank, so that the expansion element of the expansion section, which is designed in particular as a wedge and expands diametrically in the introduction direction, reaches into the expansion shell and radially separates this expansion shell and expands it. For this purpose, the expansion shell has a slot, in particular at its front end, which divides the, in particular hollow-cylindrical, base body of the expansion shell into individual expansion arms in the front section. The substrate need not form a closed cylinder. The base body can be produced in particular from a flat sheet metal by stamping, forming and/or bending and has a longitudinally continuous slot.

After the expansion zone of the expansion anchor according to the invention has been inserted into the borehole and the expansion shells have been tensioned against the wall of the borehole, the anchor shank is pulled back against the introduction direction in order to effect expansion. Thereby, the expansion element, e.g. the expansion cone, is pulled into the expansion shell, and the expansion shell is expanded, expanded and tensioned further against the wall of the borehole. The return movement of the shank relative to the expansion shell corresponds to a forward relative movement of the expansion shell relative to the shank. The radially outwardly projecting hold-down is arranged integrally on the base body in such a way that the expansion sleeve tensioned in the drill hole expands during the return movement of the anchor shank and is not moved back out of the drill hole by the return movement of the expansion element. The press-on part serves to increase the friction with the borehole wall and/or for engagement in the borehole wall, which increases the holding force of the expansion sleeve in the borehole. The press itself has a real or imaginary bottom surface, which faces the substrate, sides and a tip. The base surface lies flat against a side surface of the base body which circumscribes the base body. The base surface geometrically forms a transition from the press to the base body. The tip of the press section projects radially outward from the base and forms the radially outermost point of the press section. Furthermore, the point is arranged at the press in such a way that it forms the rear end of the press, alone or together with further points, edges or surfaces. The base surface and the tip are connected to each other by at least one side surface which intersects the base surface in the base edge. The embossed section can also have a plurality of side faces, wherein each side face intersects the base face with a base edge.

The pressed portion need not be solid. The pressing is produced in particular by pressing the base body, i.e. by pressing it locally into the material of the base body, without producing a seam or an opening. In particular, the base body is made of a strip which is bent in the circumferential direction, and the pressing part is pressed in radially outward from the strip, which is in particular arched outward. In other words, the press is in particular a bulge, in which case the material of the base body is pressed radially outward, but no material is removed from the base body. The material pressed outward forms a press which projects above the base body in the radial direction with respect to the geometry. Such a press-fit has a high resistance against radial compression when the expansion shell is inserted into the borehole.

The expansion anchor according to the invention is characterized in that the embossed section is designed such that a connecting line perpendicular to the longitudinal axis runs through the pointed end and the longitudinal axis runs through the corner point of the base. The connecting line thus forms a perpendicular to the longitudinal axis through the tip, wherein the deviation of the connecting line from the theoretically exact perpendicular can be within a manufacturing tolerance of a few degrees. The "corner point" is any point on the bottom edge. If the press has a plurality of side faces, the corner points are, in particular, the intersection points of the two side faces with the base face. The corner points form the rear end of the pressed portion together with the tip. Such a press-on has the advantage that even if the original point of the press-on is worn out during the wedging of the expansion region of the expansion anchor into the borehole, a point is additionally formed by a rearwardly directed edge extending radially with respect to the longitudinal axis between the corner point and the point, which edge lies on the connecting line. The radially outer point of this edge then serves as a tip which, when expanded, prevents the expansion shell from moving back out of the drill hole.

According to the invention, exactly one hold-down can be provided at the expansion shell. In particular, the expansion shell has at least two, in particular at least three, pressed portions which are arranged in a uniformly distributed manner in the circumferential direction on the expansion shell. If expansion arms separated by a slot are provided at the expansion shells, it is therefore possible in particular to provide a hold-down at each of the expansion arms. In particular, the pressing is not arranged in front of the expansion shell, which in particular does not form the front end of the expansion shell. Instead, the hold-down can be arranged at the rear end of the expansion shell, wherein the hold-down is preferably arranged such that its underside is completely surrounded by the lateral surface of the base body. Therefore, the pressed portion forms neither the front end portion nor the rear end portion of the expansion shell. The stamp can be embodied in particular as a pyramid, for example as a tetrahedron with a flat triangular surface, wherein the side faces can also be curved in space.

The pressure part rises in particular counter to the insertion direction along the longitudinal axis in a radial direction from the base surface toward the tip, more particularly from a base edge forming a transition to the pressure part. In this case, it is also possible to increase the height discontinuously, for example in a plurality of sections. The pressing part thus forms a wedge shape which facilitates the insertion of the expansion shell into the drill hole in the introduction direction. However, the edge formed at the rear end of the press-on part, which extends between the corner point and the tip, prevents the drill from being pulled out of the hole.

In a preferred embodiment of the expansion anchor according to the invention, at least one side of the hold-down is stretched in the circumferential direction such that it forms the rear side of the hold-down. This rear side comprises the tip of the press. This flank, which forms the rear side, lies in particular in a radial plane relative to the longitudinal axis, i.e. it runs purely in the circumferential direction. Preferably, in this embodiment, the rear flank, viewed from the rear and in the clockwise direction with respect to the longitudinal axis, rises from the base surface in the radial direction toward the tip, wherein the rise can also be discontinuous. The hold-down thus also forms a wedge in the circumferential direction, which blocks the expansion shell from rotating with it when the shank is moved back out of the borehole by rotating the nut onto the external thread serving as a load introduction device, as is customary in bolt anchors.

It is also preferred that the press-on part of the expansion anchor according to the invention has at least two flanks which intersect and whose joining edge comprises a pointed end. The two sides enclose in particular an angle of between 60 and 120 degrees, in particular an angle of between 80 and 100 degrees. In particular, the side faces enclose an angle of substantially 90 degrees. The flanks thus likewise form a wedge which prevents the expansion shell from moving out of the borehole.

Preferably, the two lateral faces are arranged orthogonally to the lateral faces of the base. "normal to the side surface of the base" means that in each intersection of the base with the side surface, the surface normal of the base lies in a tangential plane with respect to the side surface. In particular, the tangential planes are radial planes and/or axial planes, in particular, one of the tangential planes is a radial plane and the other tangential plane is an axial plane. This configuration of the side faces results in a high resistance of the expansion shells against being pulled out of the borehole.

In a further preferred embodiment of the expansion shells according to the invention, the two lateral surfaces face rearwards. This means that the two side faces project in a visible manner from behind in the top view along the insertion direction above the base body of the expansion shell. In other words: the vector of the surface normals of the side faces has a component parallel to the longitudinal axis counter to the introduction direction. Preferably, in this configuration, the two side faces are inclined with respect to the longitudinal axis. This means that, when the surface normal of the side is projected onto an axial plane of the longitudinal axis, in which the longitudinal axis lies, the projection of the surface normal is inclined relative to the longitudinal axis. The angle of inclination of the two side faces with respect to the longitudinal axis is preferably of the same magnitude. In this case, each of the inclination angles is between 30 and 60 degrees, thereby producing a wedge shape of the flank face against the pull-out direction out of the drill hole.

It is also preferred that the two side faces are symmetrical with respect to the axial plane of the longitudinal axis, which facilitates the manufacture of the press.

It is also preferred that the base edge of the base surface does not run straight, but in particular in an arc. In particular, the pressing has three base edges, two of the base edges extending linearly and the third base edge extending arcuately. In this case, the two bottom edges extending in a straight line belong to flat side faces, which extend in particular perpendicularly to the side faces of the base body and whose intersection point forms an angular point which, together with the tip, lies on a connecting straight line perpendicular to the longitudinal axis. In contrast, the arcuately extending base edge is oriented forward in particular in the insertion direction, and the associated flank, which can also be referred to as a "wedge surface" or "inclined surface", rises in the radial direction from the base edge toward the tip end counter to the insertion direction. The angle between the side surface and the wedge or inclined surface is at most 30 degrees. This configuration has proven to be particularly advantageous because it does not increase or only slightly increases the introduction resistance of the expansion shell into the drill hole, but significantly improves the resistance of the expansion shell against being pulled out of the drill hole, in comparison with the press-out known from the prior art.

Drawings

The features and feature combinations mentioned above in the description, embodiments and embodiments of the invention and the features and feature combinations mentioned below in the description of the figures and/or depicted in the figures can be used not only in the respectively stated or depicted combination but also in any other combination in principle or alone. Embodiments of the invention may not have all the features of a dependent claim. The individual features of a claim can also be replaced by other disclosed features or combinations of features. Embodiments of the invention are possible which do not have all the features of the examples, but which in principle have any part of the features of the characterizing part of the examples, if appropriate in combination with one, more or all of the features of the further examples.

In the following, the invention is explained in more detail with reference to the figures. It shows that:

FIG. 1 is a side view of a first expansion anchor according to the present invention;

FIG. 2 is an enlarged schematic view of the expansion region of a first expansion anchor according to the present invention in a side view rotated 90 about the longitudinal axis relative to FIG. 1;

FIG. 3 is a top plan view of a deployed view of an expansion shell of a first expansion anchor according to the present invention;

FIG. 4 is a top plan view of a deployment view of an alternative expansion shell for use with the expansion anchor according to the present invention; and

fig. 5 is a schematic sectional view of the expansion arms of the alternative expansion shells of fig. 4, taken along section line V-V.

Detailed Description

In fig. 1a first expansion anchor 1 according to the invention for anchoring in an anchoring base made of concrete is shown. The expansion anchor 1 comprises a shank 2 made of metal, which extends along a longitudinal axis L from a rear end 3 in an introduction direction E of the expansion anchor 1 into a borehole in an anchoring bottom (not shown) up to a front end 4. The rear end 3 of the expansion anchor 1 forms the striking surface of the hammer bolt 5, to which the external thread 6 adjoins as a load introduction device 7. A nut 8 is screwed onto the external thread 6, with which nut a washer 9 can be tightened against an attachment (not shown) against the anchoring bottom. Along the insertion direction E, an unthreaded spacing section 10 adjoins the external thread 6, which spacing section has a collar 11 that forms a stop for an expansion sleeve 12. In front of the flange 11 in the introduction direction E, the shank 2 has an expansion section 13 in which an expansion sleeve 12 circumferentially surrounds a neck section of the shank 2, which neck section has a reduced diameter. The expansion shell 12 is secured against loss by said surrounding, but can be displaced forward along the longitudinal axis L relative to the shank 2 towards an expansion cone 15 which serves as an expansion element 14. The expansion shell 12 has two slots 16 which run longitudinally from the front end of the expansion shell 12 back and end in the rear in a bore 19 and which divide the first two thirds of the expansion shell 12 into three expansion arms 17 which are pressed radially outwards for expansion when the expansion shell 12 is fitted onto the expansion cone 15. The distribution of the slots 16 and the expansion arms 17 can be clearly seen in fig. 3, which fig. 3 shows a flat development of the expansion shell 12 or the expansion shell 12 before bending this around the neck section of the shank 2.

A punch 18 is arranged on each of the expansion arms 17, so that the expansion shells 12 find a fixed fulcrum in the drill hole before expansion after the expansion section 13 of the expansion anchor 1 has been inserted into the drill hole, so that the expansion shells 12 can be expanded by moving the anchor shank 2 counter to the introduction direction E by tightening the nut 8. The punch 18 projects radially outwardly from the base 20 of the expansion shell 12. The base body 20 is formed from a flat, undeformed strip from which the expansion shells 12 are produced. In the unexpanded state of the expansion anchor 1, as shown in fig. 1 and 2, the base body 20 has a cylindrical lateral surface 21 which in the expanded view of fig. 3 has a flat rectangular surface 22. The punch 18 arranged on the base body 20 has an imaginary bottom surface 23, three

side surfaces

24, 25, 26 and a tip 27, respectively. The bottom surface 23 faces the base body 20 and rests against this base body. The bottom surface 23 forms a purely geometrically separate surface between the punch 18 and the side surface 21 of the base body 20. The bottom surface 23 is divided by three

side surfaces

24, 25, 26Connected to the tip 27. Each of the nibs 27 of the three stampings 18 of the expansion shell 12 projects radially outwards from the base body 20 and forms a radially outermost point and a respective rear end of the stampings 18. The punch 18 is designed such that a connecting line 28 perpendicular to the longitudinal axis L runs from the respective tip 27 through an angle point 29 of the base 23 to the longitudinal axis L (fig. 2). Between the corner point 29 and the tip 27, a connecting line 28 forms an interface cut 30 between the first side 24 and the second side 25. This cutting edge 30 forms, together with the tip 27, a corresponding rear end of the punch 18. The two side faces 24, 25 extend orthogonally, i.e. perpendicularly, to the side face 21 of the base body 20. Both rise radially from the bottom surface 23 back towards the tip 27 and face rearward and are the same size. The first side surface 24 and the second side surface 25 are each inclined at an angle α of 45 ° relative to the longitudinal axis L₁、α₂Tilted as shown in fig. 1. The two

side surfaces

24, 25 are thus symmetrical with respect to the axial plane of the longitudinal axis L. The third side 26 has the shape of a sector in the top view of the developed view of fig. 3, the corner point 29 forming the center point of the sector. The junction of the third side 26 and the base 23 thus forms a base edge 31 which extends not in a straight line but in an arc, in the expanded view in the form of a circular arc.

If the expansion shell 12 is introduced into the borehole, the tip 27 engages into the borehole wall and holds the expansion shell 12 in the borehole. Since the punch 18 is punched out of the base body 20 instead of being punched out, the punch is configured to be stable and to be less compressible in the radial direction than a stamped and bent cantilever-shaped wing. Since the tip 27 and the meeting edge 30 form the rear end of each punch 18, the tip 27 is protected from deformation due to friction at the drill hole wall during insertion. However, even if the point 27 is worn during insertion, the outwardly and rearwardly tapering meeting edge 30 remains engaged in the borehole wall.

Fig. 4 and 5 show an alternative embodiment of an expansion shell 12a which is identical to the expansion shell 12 from fig. 1 to 3, except for the punched section 18 a. To avoid redundancy, only the punched portion 18a will be discussed below. In the plan view of the development, the punch 18a is likewise a sector whose outer geometry is identical to the outer geometry of the punch 18 described above, but is rotated by 45 ° relative to the longitudinal axis L in comparison with the punch 18 described above. As a result of said rotation, the second flank 25a is parallel to the longitudinal axis L and the first flank 24a extends in the circumferential direction. The first side 24a forms the rear side of the stamped part 18a, which here faces rearward as the only side 24 a. Viewed from behind in the direction of introduction E and in the clockwise direction with respect to the longitudinal axis L, rises from the base surface 23 in the radial direction toward the tip 27.

In both configurations of the

expansion shells

12, 12a, the

flanks

26, 26a of the

stampings

18, 18a form wedge faces which rise in the radial direction towards the rear. This facilitates insertion into the drilled hole. The radially outer end of the

point

27, 27a or the connecting

edge

30, 30a holds the

expansion shell

12, 12a for expansion securely in the drill hole and prevents the

expansion shell

12, 12a from being displaced out of the drill hole by the expansion cone 15 and together with the expansion cone 15 when expanding.

List of reference numerals

1 expansion anchor

2 Anchor shank

3 rear end of expansion anchor 1

4 front end of expansion anchor 1

5 hammer bolt

6 external screw thread

7 load introduction apparatus

8 nut

9 shim

10 pitch segment

11 Flange

12. 12a expansion sleeve

13 expansion section

14 expansion element

15 expansion cone

16 seams

17 expansion arm

18. 18a press part

19 drilling

20 base body

21 side surface

22 rectangular surface

23. 23a bottom surface

24. 24a first side

25. 25a second side

26. 26a third side

27. 27a tip

28 straight connecting line

29. Corner point 29a

30. 30a connecting edge

31. 31a bottom edge

E direction of introduction

L longitudinal axis

α₁Angle of inclination of the first side 24

α₂The angle of inclination of the second side 25.

Claims

1. Expansion anchor (1) for anchoring in concrete, having a shank (2) made of metal, which shank extends along a longitudinal axis (L) and has a load introduction device (7) at the rear and an expansion section (13) at the front, wherein an expansion sleeve (12, 12 a) made of metal is arranged at the expansion section (13), wherein the expansion sleeve (12, 12 a) circumferentially surrounds the shank (2) and can be moved forward along the longitudinal axis (L) relative to the shank (2), wherein the expansion sleeve (2) has a base body (20) at which a pressing portion (18, 18 a) projecting radially outward from the base body (20) is integrally arranged, the pressing portion having a bottom face (23, 23 a), at least one side face (24, 24a, 25 a), 26. 26 a) and a tip (27, 27 a), wherein the bottom surface (23, 23 a) faces the base body (20), the side surface (24, 24a, 25a, 26 a) connects the bottom surface (23, 23 a) with the tip (27, 27 a), the tip (27, 27 a) protrudes radially outward from the base body (20) and forms a radially outermost point and a rear end of the pressing portion (18, 18 a),

it is characterized in that the preparation method is characterized in that,

the pressed sections (18, 18 a) are designed in such a way that a straight connecting line (28) running perpendicular to the longitudinal axis (L) runs through the tip (27, 27 a), and the longitudinal axis (L) runs through a corner point (29, 29 a) of the base (23, 23 a).

2. Expansion anchor according to claim 1, wherein the side (24 a) of the pressing (18 a) stretches in the circumferential direction and forms the rear side of the pressing (18 a), which comprises the point (27 a).

3. Expansion anchor according to claim 2, wherein the side surface (24 a) rises radially from the bottom surface (23 a) towards the tip (27 a) as seen from behind and in a clockwise direction with respect to the longitudinal axis (L).

4. Expansion anchor according to any one of the preceding claims, wherein the press (18, 18 a) has at least two intersecting side faces (24, 24a, 25 a), the meeting edges (30, 30 a) of which comprise the pointed end (27, 27 a).

5. Expansion anchor according to claim 4, wherein the two lateral faces (24, 24a, 25 a) are arranged orthogonal to the lateral surface (21) of the base body (20).

6. Expansion anchor according to claim 4 or 5, wherein the two sides (24, 25) face rearwards.

7. Expansion anchor according to any one of claims 4 to 6, wherein the two lateral faces (24, 25) are inclined with respect to the longitudinal axis (L).

8. Expansion anchor according to claim 7, wherein the inclination angle (α) of the two flanks (24, 25) is such that₁、α₂) The same is true.

9. Expansion anchor according to any one of claims 4 to 8, wherein the two lateral faces (24, 25) are symmetrical with respect to an axial plane of the longitudinal axis (L).

10. Expansion anchor according to one of the preceding claims, wherein the bottom edges (31, 31 a) of the bottom faces (23, 23 a) do not run straight, but in particular arc-shaped.