Expansion anchor with angled contact wall transition edge

Abstract

An expansion anchor comprising an anchor bolt having a longitudinal axis, an expansion sleeve surrounding the anchor bolt, and an expansion body located in the front region of the anchor bolt, the expansion body having a convergence zone for expanding the expansion sleeve, wherein the expansion body is provided with a contact wall recess. This contact wall recess is defined by a sleeve contact wall axially facing the expansion sleeve, so as to provide contact for the expansion sleeve when the expansion sleeve is moved axially toward the sleeve contact wall. This contact wall recess is further defined by a recess bottom. A transition edge is formed between the recess bottom and the sleeve contact wall. The transition edge extends with a lead angle α. In at least one region of the transition edge, 4° ≤ α ≤ 30° holds with respect to the lead angle α.

Description

Technical Field

[0001] The present invention relates to an expansion anchor as set forth in the preamble of claim 1.

Background Art

[0002] Patent Document 1 and Patent Document 2 describe expansion anchors each provided with a sleeve abutment wall on the expansion body of the expansion anchor. The sleeve abutment wall is formed in an abutment wall recess provided in the respective expansion body. The sleeve abutment wall is intended to bear against the respective expansion sleeve when the anchor is expanded.

[0003] Patent Document 3 and Patent Document 4 show expansion anchors having related configurations.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide an expansion anchor which has particularly satisfactory performance while having particularly low manufacturing effort.

Means for Solving the Problems

[0006] This object is achieved by the expansion anchor according to claim 1. The dependent claims describe preferred embodiments.

[0007] In other words, it is an extension anchor, An anchor bolt having a longitudinal axis, An expansion sleeve surrounding the anchor bolt, An expansion body located in the front region of an anchor bolt, the expansion body having a convergence zone for expanding an expansion sleeve, the expansion body comprising a contact wall recess, the contact wall recess being defined by a sleeve contact wall axially facing the expansion sleeve to provide contact for the expansion sleeve when the expansion sleeve is moved axially toward the sleeve contact wall, the contact wall recess being further defined by a recess bottom, specifically defined radially, and a transition edge being formed between the recess bottom and the sleeve contact wall, the expansion body An extended anchor is provided, including the following.

[0008] This extended anchor is characterized in that the transition edge extends at a lead angle α, and in at least one region of the transition edge, the condition 4° ≤ α ≤ 30° holds for the lead angle α.

[0009] The present invention is based on providing an expansion body having a sleeve contact wall, the sleeve contact wall facing the expansion sleeve before the anchor is installed, and therefore, when the anchor is installed, the expansion sleeve can contact the expansion sleeve contact wall as the expansion body moves along the expansion sleeve during the expansion of the expansion sleeve. As described above (for example, in Patent Document 2), this can advantageously adjust the fixing process. The present invention therefore proposes arranging a transition edge, formed between the bottom of the recess and the sleeve contact wall and forming the base of the sleeve contact wall, in a relationship not perpendicular to the longitudinal axis of the anchor bolt. More specifically, the transition edge extends at least in one area of ​​the transition edge, preferably across the entire transition edge, with a lead angle α of 4° to 30°.

[0010] This angled arrangement of the transition edge allows for gradual axial contact and / or a gradual increase in internal resistance, which can be achieved with particularly little manufacturing effort, and may be beneficial in terms of fixing performance. On the other hand, the angle has an upper limit, which provides a large contact area without requiring excessively large dimensions, further reducing labor.

[0011] It is particularly preferable that, in at least one region of the transition edge, the condition 4° ≤ α ≤ 16° holds for the lead angle α.

[0012] More preferably, in at least one region of the transition edge, the condition 9° ≤ α ≤ 11° holds for lead angle α. These are particularly appropriate lead angles considering performance and effort.

[0013] It is particularly advantageous that the lead angle α satisfies 4° ≤ α ≤ 30°, or 4° ≤ α ≤ 16°, or 9° ≤ α ≤ 11° across the entire transition edge. Thus, the entire transition edge falls within the described range. Alternatively or additionally, the lead angle α over which the transition edge extends may be approximately constant across the entire transition edge. All of these can provide particularly uniform operation.

[0014] An anchor bolt is an elongated body. The expansion body and the anchor bolt are connected specifically to transmit tension axially. Specifically, if the expansion anchor is a so-called sleeve-type expansion anchor, the expansion body can be screwed onto the anchor bolt, for example. Specifically, if the expansion anchor is a so-called stud-type expansion anchor, the expansion body can also be firmly fixed to the anchor bolt. In the case of a stud-type expansion anchor, it is particularly preferable that the expansion body and the anchor bolt are monolithic, that is, they form a single part. If the expansion anchor is a so-called stud-type expansion anchor, the anchor bolt preferably has a forward-facing shoulder for contacting the expansion sleeve and for advancing the expansion sleeve into the borehole. The expansion body is part of the expansion anchor.

[0015] The expansion sleeve specifically surrounds the anchor bolt around its longitudinal axis. Preferably, the expansion sleeve is a single piece. However, it can also consist of several separate segments, which are held in place, for example, by rubber bands or a snap-on mechanism in the arrangement surrounding the anchor bolt.

[0016] Preferably, the anchor bolts, expansion sleeves, and / or expansion bodies are each made of steel. They may include, for example, carbon steel or stainless steel.

[0017] The front region of the anchor bolt where the extension body is located is the region intended to precede the extension anchor when it is inserted into the borehole. The longitudinal axis of the anchor bolt extends through the front and rear regions of the anchor bolt.

[0018] An anchor bolt may have a tension introduction structure in the rear region of the anchor bolt. The tension introduction structure is for introducing tension into the anchor bolt. The tension introduction structure may be, for example, a screw provided on the anchor bolt, specifically an external thread. However, in other embodiments, the tension introduction structure may also be, for example, a head that forms the maximum cross-section, or a bayonet lock.

[0019] The convergence zone of the expansion body functions to expand the expansion sleeve when the expansion sleeve is moved forward relative to the expansion body, specifically, to expand the expansion sleeve radially with respect to the longitudinal axis. In the convergence zone, the expansion body converges on its side toward the rear of the anchor bolt and / or toward the tension introduction structure, and the focal point of convergence may preferably be the longitudinal axis. This specifically means that the radial distance from the longitudinal axis on the side of the expansion body decreases toward the rear of the expansion body. The expansion body may have additional zones, for example, a preferably cylindrical transition zone and / or tip zone. The convergence zone may be, for example, conical, or may have a more complex shape, for example, convex or concave. Specifically, the convergence zone forms a wedge for the expansion sleeve.

[0020] The sleeve contact wall is specifically positioned so that the expansion sleeve can contact the sleeve contact wall when the expansion sleeve is displaced axially forward relative to the expansion body, i.e., toward the front end of the expansion body and / or anchor bolt, by pulling the expansion body backward into the expansion sleeve. Thus, the sleeve contact wall faces the expansion sleeve axially, or in other words, faces the expansion sleeve in a direction parallel to the longitudinal axis. Preferably, the sleeve contact wall faces the tip of the expansion sleeve axially and / or functions for contact of the tip of the expansion sleeve, and can therefore be named an expansion sleeve tip contact wall. The tip of the expansion sleeve can be understood as the front end of the expansion sleeve, i.e., the end facing forward. The sleeve contact wall is positioned opposite the expansion sleeve, specifically the tip of the expansion sleeve, and specifically opposite in the axial direction. Specifically, in the state before the expansion sleeve is expanded by the expansion body, that is, in the pre-installation state of the anchor before the anchor is installed, the sleeve contact wall faces the expansion sleeve, specifically the tip of the expansion sleeve, in the axial direction. Specifically, the sleeve contact wall faces toward the rear of the anchor. The anchor is configured such that, during the axial displacement of the expansion body relative to the expansion sleeve and / or during the radial expansion of the expansion sleeve by the expansion body, the expansion sleeve, specifically with its tip, can contact the sleeve contact wall. Therefore, the sleeve contact wall is specifically suitable for and / or configured to be contacted in the axial direction by the expansion sleeve and / or by the tip of the expansion sleeve. Specifically, the sleeve contact wall is suitable for and / or configured to be contacted in the axial direction by a section of the expansion sleeve, specifically the front end section, which is curved about the longitudinal axis and / or is positioned approximately perpendicular to the longitudinal axis.

[0021] Specifically, the sleeve abutment wall projects radially on the expansion body, and / or the step structure is formed on the sleeve abutment wall, and the sleeve abutment wall forms the riser of each step structure. The sleeve abutment wall is arranged on the side surface of the expansion body, that is, on the lateral side of the expansion body.

[0022] Specifically, the expansion body is provided with an abutment wall recess on its side surface, and the abutment wall recess is specifically axially defined at its front end by the sleeve abutment wall. Therefore, the sleeve abutment wall forms the front end wall of the abutment wall recess. Specifically, the abutment wall recess extends radially into the expansion body. The abutment wall recess is preferably located at least partially in the convergence zone of the expansion body.

[0023] The recess bottom forms a further wall of the abutment wall recess, and / or radially defines the abutment wall recess.

[0024] The recess bottom and the sleeve abutment wall intersect geometrically, and a transition edge is formed at the position where the recess bottom and the sleeve abutment wall intersect. Therefore, both the recess bottom and the sleeve abutment wall are adjacent to the transition edge. The transition edge is located inside the abutment wall recess.

[0025] The lead angle is a lead angle relative to the longitudinal axis. According to the usual definition, the lead angle can be regarded as the angle between the tangent on the transition edge and a plane oriented perpendicular to the longitudinal axis.

[0026] Where the term "longitudinal axis" is used, it should specifically refer to the longitudinal axis of the anchor bolt, which normally may coincide with the longitudinal axis of the expansion anchor. According to the usual definition, the "longitudinal axis" may specifically be an axis extending in the longitudinal direction, that is, the longitudinal direction of the elongated anchor bolt. Where the terms "radially", "axially" or "circumferentially" are used, this should be understood specifically with respect to the longitudinal axis of the anchor bolt.

[0027] According to a preferred embodiment of the present invention, the radial height of the sleeve contact wall preferably gradually decreases toward the rear of the anchor bolt and / or toward the rear of the expansion body. Thus, the sleeve contact wall becomes higher as it approaches the front end of the expansion body in the axial direction. This allows the expansion sleeve to gradually rise against the angled sleeve contact wall as the expansion body is drawn into the expansion sleeve, further improving performance.

[0028] It is particularly advantageous that at least one sleeve abutment wall tapers toward the rear of the anchor bolt. Therefore, preferably, the sleeve abutment wall is not perpendicular to the longitudinal axis, at least as a whole. Rather, the radius of the extension body gradually decreases toward the rear of the anchor bolt at the sleeve abutment wall. This makes it possible to create an obstacle that can be overcome in a particularly reliable and easily manufactured manner.

[0029] The expansion body may have a transition zone located before the convergence zone. In such a transition zone, the convergence of the expansion body is at least not steeper than in the convergence zone, or there may be no convergence at all. Such a transition zone can prevent the expansion sleeve from being over-expanded and the surrounding substrate from being subjected to excessive stress under high load. If there is no convergence at all, the transition zone may have cylindrical sides, where the cylindrical shape should be understood in a broad sense, and the cylindrical bottom may but does not necessarily have to be circular.

[0030] The sleeve contact wall and / or transition edge are preferably located at least partially, and preferably completely, within the convergence zone. If a transition zone exists, the sleeve contact wall and / or transition edge can also reach this transition zone.

[0031] It is particularly preferable that the extension body has at least one additional contact wall recess, preferably two or three additional contact wall recesses. The at least one additional contact wall recess preferably has substantially the same shape and / or function as the contact wall recess. The contact wall recess and the at least one additional contact wall recess are preferably arranged side by side, i.e., in the same axial orientation.

[0032] Furthermore, the expansion body may include additional walls, such as recessed side walls, which do not face the expansion sleeve axially and / or are not suitable for contact with the expansion sleeve during axial displacement of the expansion sleeve and therefore cannot be called sleeve contact walls.

[0033] The present invention will be described in more detail below with reference to preferred embodiments schematically illustrated in the accompanying drawings. Each of the embodiments presented below may be implemented individually or in any combination. [Brief explanation of the drawing]

[0034] [Figure 1] This is a side view of the extension anchor. [Figure 2] This is a side view of the same expansion anchor as in Figure 1, with the expansion sleeve omitted. [Figure 3] This is a perspective view of the anchor bolt in the front region of the anchor bolt, including the extended body 20. [Figure 4] This is a side view of the anchor bolt in the front region of the anchor bolt, including the extension body 20. [Figure 5] This is a side view of the same anchor bolt as in Figure 4, with all reference numerals and auxiliary lines omitted. [Modes for carrying out the invention]

[0035] The figure shows an embodiment of the expansion anchor of the present invention. The anchor includes an elongated anchor bolt 10 having a front end (left end in Figure 2) and a rear end (right end in Figure 2), an expansion sleeve 30 surrounding the anchor bolt 10, and an expansion body 12 for expanding the expansion sleeve 30 radially, the expansion body 12 being provided on the anchor bolt 10, i.e., near the front end of the anchor bolt 10. The anchor bolt 10 has a longitudinal axis 99 that extends through the front end and through the rear end of the anchor bolt 10. The longitudinal axis 99 passes through the expansion sleeve 30.

[0036] The extension body 12 has a convergence zone 23 designed to radially expand the expansion sleeve 30 when the extension body 12 is retracted rearward into the expansion sleeve 30, that is, when the expansion sleeve 30 moves forward relative to the extension body 12 toward the extension body 12. For this purpose, the sides of the extension body 12 converge toward the rear end of the anchor bolt 10, that is, converge toward the expansion sleeve 30, at least before the anchor is installed. In this embodiment, the sides of the extension body 12 are conical in the convergence zone 23, which has a focal point of convergence on the longitudinal axis 99 and an apex angle β, as shown in Figure 2. However, this is merely an example, and other convergence designs are possible.

[0037] In this embodiment, the extension body 12 also has a transition zone 22 located in front of and adjacent to the convergence zone 23, and a tip zone 21 located in front of and adjacent to the transition zone 22. In the transition zone 22, the backward convergence is smaller than in the convergence zone 23, or the backward convergence is zero, preferably not in the opposite direction, i.e., not forward convergence. In this embodiment, there is no convergence in the convergence zone 23, i.e., zero, and the extension body 12 has cylindrical sides in the convergence zone 23, specifically cylindrical sides with a circular bottom. In the tip zone 21, the sides of the extension body 12 converge toward the front end of the anchor.

[0038] The anchor bolt 10 has a neck 25 located adjacent to and behind the expansion body 12. The expansion sleeve 30 surrounds this neck 25 at least partially, at least before the anchor is installed. The diameter of the anchor bolt 10 can be minimal at the neck 25. In this embodiment, the anchor bolt 10 has a plurality of axially extending grooves within its neck 25, and the expansion sleeve 30 has corresponding axially extending protrusions that engage with the axially extending grooves, but this is only an example.

[0039] In this embodiment, the anchor is of the stud type. The anchor bolt 10 has a forward-facing shoulder 17 at the rear end of the neck 25 for axial engagement with the expansion sleeve 30 and for advancing the expansion sleeve 30 forward. In this embodiment, the expansion body 12 and the anchor bolt 10 are monolithic as an example, but this is just one example, and non-monolithic designs are also possible.

[0040] In the rear region of the anchor bolt 10, the anchor bolt 10 is provided with a tension introduction structure 18, which in this case takes the form of an external thread.

[0041] The expansion sleeve 30 has a number of slits 36' (four in this example, of which only one is visible in Figure 1) that start from the front end of the expansion sleeve 30 and extend toward the rear end of the expansion sleeve 30.

[0042] The side surface of the extension body 12 is provided with a contact wall recess 66 that provides a recess within the extension body 12 and is radially accessible from the outside of the extension body 12. The contact wall recess 66 extends at least within the convergence zone 23 of the extension body 12. In this embodiment, the contact wall recess 66 extends only within the extension body 12, but in other embodiments, it may also extend into the neck 25.

[0043] The abutment wall recess 66 is defined radially by the recess bottom 62. At its front end, the abutment wall recess 66 is defined axially by the sleeve abutment wall 60. The sleeve abutment wall 60 faces the expansion sleeve 30 axially, i.e., the sleeve abutment wall 60 faces rearward. The sleeve abutment wall 60 may be positioned perpendicular to the longitudinal axis 99, but in the illustrated embodiment, the sleeve abutment wall 60 and the longitudinal axis 99 converge toward the rear end of the anchor bolt 10.

[0044] The sleeve contact wall 60 forms a preferably overcomeable contact for the front end, i.e., for the tip of the expansion sleeve 30. The expansion sleeve 30 is intended to contact the sleeve contact wall 60 when the expansion body 12 is drawn into the expansion sleeve 30 and the expansion sleeve 30 is displaced forward relative to the expansion body 12.

[0045] A transition edge 69 is formed where the recessed bottom 62 intersects with the sleeve contact wall 60. In other words, the transition edge 69 is adjacent to both the recessed bottom 62 and the sleeve contact wall 60.

[0046] Specifically, the transition edge 69 is positioned at a lead angle α with respect to a plane 91 that is perpendicular to the longitudinal axis 99. This lead angle α is generally constant throughout the transition edge 69. In this embodiment, it is approximately 10°.

[0047] The radial height (relative to the longitudinal axis 99) of the sleeve contact wall 60 is not constant. Rather, this height decreases towards the rear of the anchor bolt 10.

[0048] The extension body 12 is provided with at least one additional contact wall recess (in this embodiment, as an example, there are three additional contact wall recesses, of which only two, indicated as 66' and 66''' respectively, are visible in the drawings). Each of these additional contact wall recesses 66', 66''' has a shape substantially the same as that of the contact wall recess 66. Specifically, each of these additional contact wall recesses 66', 66''' is defined radially by the bottom of the additional recess, and at the front end of each, each of the additional contact wall recesses is defined axially by an additional sleeve contact wall facing the extension sleeve, i.e., facing rearward. An additional transition edge is formed where the bottom of the additional recess intersects with the additional sleeve contact wall. At least one additional sleeve contact wall and the sleeve contact wall 60 are located side by side, at the same position along the longitudinal axis 99, and do not overlap circumferentially.

[0049] Anchors can be installed as follows:

[0050] In the first step, the anchor, starting with its front end, is introduced into the hole in the substrate.

[0051] Next, the expansion body 12 is retracted into the front end region of the expansion sleeve 30, which means that the expansion sleeve 30 is displaced forward relative to and above the expansion body 12. In this embodiment, this is achieved by pulling the anchor bolt 10 backward together with the expansion body 12, specifically by tightening a nut (not shown) provided on the tension introduction structure 18 of the anchor bolt 10. The retraction of the expansion body 12 into the expansion sleeve 30 expands the expansion sleeve 30 radially, thereby locking the anchor into the substrate.

[0052] When the expansion body 12 is pulled sufficiently deep into the expansion sleeve 30, the expansion body 12 finally strikes the sleeve contact wall 60 with its tip. This can create an axial interlock between the expansion sleeve 30 and the expansion body 12 at the sleeve contact wall 60, resulting in a change in the expansion mechanism. This, in turn, can lead to an increase in pull-out resistance without excessive stress on the substrate. Due to the non-vertical lead angle α, and because the radial height of the sleeve contact wall 60 gradually increases toward the front end of the anchor bolt 10, the engagement of the sleeve contact wall 60 by the expansion sleeve 30 can be expected to be a gradual process, resulting in a gradual change in the fixing characteristics.

Claims

1. An anchor bolt (10) having a longitudinal axis (99), The expansion sleeve (30) surrounds the anchor bolt (10), An extension body (12) located in the front region of the anchor bolt (10), wherein the extension body (12) has a convergence zone (23) for extending the extension sleeve (30), the extension body (12) comprises a contact wall recess (66), the contact wall recess (66) is defined by a sleeve contact wall (60) axially facing the extension sleeve (30) to provide contact for the extension sleeve (30) when the extension sleeve is moved axially toward the sleeve contact wall (60), the contact wall recess (66) is further defined by a recess bottom (62), and a transition edge (69) is formed between the recess bottom (62) and the sleeve contact wall (60), An extended anchor that includes, The transition edge portion (69) extends with a lead angle α, and in at least one area of ​​the transition edge portion (69), the condition 4° ≤ α ≤ 30° holds for the lead angle α. An extension anchor characterized by the following features.

2. The expansion anchor according to claim 1, characterized in that, in at least one area of ​​the transition edge portion (69), the condition 4° ≤ α ≤ 16° holds for the lead angle α.

3. The expansion anchor according to claim 1 or 2, characterized in that, in at least one area of ​​the transition edge portion (69), the condition 9° ≤ α ≤ 11° holds for the lead angle α.

4. The expansion anchor according to any one of claims 1 to 3, characterized in that the lead angle α satisfies 4° ≤ α ≤ 30°, or 4° ≤ α ≤ 16°, or 9° ≤ α ≤ 11° over the entire transition edge portion (69).

5. The extension anchor according to any one of claims 1 to 4, characterized in that the lead angle α over which the transition edge portion (69) extends is substantially constant over the entire transition edge portion (69).

6. The expansion anchor according to any one of claims 1 to 5, characterized in that the radial height of the sleeve contact wall (60) gradually decreases toward the rear of the anchor bolt (10).

7. The expansion anchor according to any one of claims 1 to 6, characterized in that at least one of the sleeve contact walls (60) tapers toward the rear of the anchor bolt (10).

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