Expansion anchor with angled abutment wall transition edge

Abstract

The expansion anchor includes 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 region for expanding the expansion sleeve. The expansion body is provided with an abutment wall recess. The abutment wall recess is defined by a sleeve abutment wall axially facing the expansion sleeve to provide abutment for the expansion sleeve as the expansion sleeve moves axially toward the sleeve abutment wall. The abutment wall recess is further defined by a recess floor. A transition edge is formed between the recess floor and the sleeve abutment wall. The transition edge extends at a lead angle alpha. At least in a portion of the transition edge, the following is applied for the lead angle alpha: 4 DEG < = alpha < = 30 DEG.

Description

Technical Field

[0001] The present invention relates to an expansion anchor as described in the preamble of claim 1. Background Technology

[0002] US2021231150 A1 and US2020224695 A1 describe expansion anchors having sleeve abutment walls on their expansion bodies. The sleeve abutment walls are formed at abutment wall recess disposed within the respective expansion body. When the anchor expands, the sleeve abutment walls are intended to be contacted by the corresponding expansion sleeve.

[0003] EP4074991 A1 and EP4074990 A1 show expansion anchors with relevant geometries. Summary of the Invention

[0004] The object of this invention is to provide an expansion anchor that has particularly satisfactory performance while having particularly low manufacturing cost.

[0005] This objective is achieved by the expansion anchor according to claim 1. The dependent claims describe preferred embodiments.

[0006] Therefore, an expansion anchor is provided, which includes: - Anchor bolt, which has a longitudinal axis. - An expansion sleeve, which surrounds the anchor bolt, and - An expansion body, located in the front region of the anchor bolt, wherein the expansion body has a converging region for expanding the expansion sleeve, wherein the expansion body is provided with an abutment wall recess, wherein the abutment wall recess is defined by a sleeve abutment wall axially facing the expansion sleeve to provide abutment for the expansion sleeve as it moves axially toward the sleeve abutment wall, and wherein the abutment wall recess is further defined by a recess base plate, particularly radially, wherein a transition edge is formed between the recess base plate and the sleeve abutment wall. The characteristics of an expansion anchor are: - The transition edge extends with a lead angle α, wherein at least in a portion of the transition edge, the following applies to the lead angle α: 4°≤α≤30°.

[0007] The basis of this invention is to provide a sleeve abutment wall for the expansion body, which faces the expansion sleeve before the anchor is installed, such that when the anchor is installed, the expansion sleeve can contact the sleeve abutment wall as the expansion body moves along the expansion sleeve during its expansion. As previously described (e.g., in US2020224695 A1), this can advantageously regulate the anchoring process. The invention now proposes arranging the transition edge formed between the recessed base plate and the sleeve abutment wall, and forming the root of the sleeve abutment wall, in a non-perpendicular relationship relative to the longitudinal axis of the anchor bolt. More specifically, at least in a portion of the transition edge, and preferably throughout the entire transition edge, the transition edge extends with a lead angle α greater than or equal to 4° and less than or equal to 30°.

[0008] Due to this angled arrangement of the transition edges, progressive axial contact and / or gradually increasing internal resistance can be achieved at a particularly low manufacturing cost, which in turn can benefit anchoring performance. On the other hand, this angle has an upper limit, which provides a significant contact area without requiring excessively large dimensions, thereby further reducing costs.

[0009] Particularly preferred is that, at least in a portion of the transition edge, the following applies to the lead angle α: 4°≤α≤16°.

[0010] More preferably, at least in a portion of the transition edge, the following applies to the lead angle α: 9°≤α≤11°. These are particularly suitable lead angles considering performance and cost.

[0011] Of particular advantage is that, throughout the entire transition edge, the following applies to the lead angle α: 4°≤α≤30°, or 4°≤α≤16°, or 9° ≤ α ≤ 11°. Therefore, the entire transition edge lies within the described range. Alternatively or additionally, the transition edge, with its extended lead angle α, can be approximately constant across the entire transition edge. All of these provide particularly uniform operation.

[0012] The anchor bolt is an elongated body. The expansion body and the anchor bolt are specifically connected to transmit tensile force in the axial direction. Specifically, if the expansion anchor is a so-called sleeve-type expansion anchor, the expansion body can be threaded to the anchor bolt, for example. Specifically, if the expansion anchor is a so-called stud-type expansion anchor, the expansion body can also be tightly secured to the anchor bolt. In the case of a stud-type expansion anchor, it is particularly preferred that the expansion body and the anchor bolt are integral, i.e., they form a single unit. If the expansion anchor is a so-called stud-type expansion anchor, the anchor bolt preferably has a forward-facing shoulder for abutting the expansion sleeve and for advancing the expansion sleeve into the borehole. The expansion body is part of the expansion anchor.

[0013] The expansion sleeve surrounds the anchor bolt, particularly around the longitudinal axis. Preferably, the expansion sleeve is a single integral piece. However, the expansion sleeve may also consist of several separate segments, which are held in an arrangement around the anchor bolt, for example by means of rubber bands or snap-fit ​​mechanisms.

[0014] Preferably, the anchor bolts, expansion sleeves, and / or expansion bodies are all made of steel. For example, these steel parts may include carbon steel or stainless steel.

[0015] The front region of the anchor bolt is designed to guide the expansion anchor when it is inserted into the borehole, and the expansion body is located in this front region. The longitudinal axis of the anchor bolt extends through both the front and rear regions.

[0016] Anchor bolts may have a tension-introducing structure in the rear region of the anchor bolt. This tension-introducing structure is used to introduce tensile force into the anchor bolt. The tension-introducing structure may be, for example, a thread provided on the anchor bolt, particularly an external thread. However, in other embodiments, the tension-introducing structure may also be, for example, a head forming the maximum cross-section, or a bayonet-type lock.

[0017] As the expansion sleeve moves forward relative to the expansion body, the convergence zone of the expansion body serves to expand the expansion sleeve, particularly radially relative to the longitudinal axis. In the convergence zone, the side surfaces of the expansion body converge toward the rear of the anchor bolt and / or toward the tension-introducing structure, with the focal point of convergence preferably being the longitudinal axis. This specifically means that the radial distance between the side surfaces of the expansion body and the longitudinal axis decreases toward the rear of the expansion body. The expansion body may have additional regions, such as preferably cylindrical transition regions and / or pointed regions. The convergence zone may be, for example, conical, or may have more complex shapes, such as convex or concave shapes. In particular, the convergence zone forms a wedge-shaped portion of the expansion sleeve.

[0018] The sleeve abutment wall is arranged such that when the expansion sleeve is axially displaced relative to the expansion body in the forward direction, i.e., axially displaced toward the front end of the expansion body and / or the anchor bolt, particularly by pulling the expansion body into the expansion sleeve in the rearward direction, the expansion sleeve can contact the sleeve abutment wall, i.e., the expansion sleeve can abut against the sleeve abutment wall. Therefore, the sleeve abutment wall faces the expansion sleeve axially, or in other words, the sleeve abutment wall faces the expansion sleeve in a direction parallel to the longitudinal axis. Preferably, the sleeve abutment wall faces the tip of the expansion sleeve and / or serves to abut against the tip of the expansion sleeve, and can therefore be called the expansion sleeve tip abutment wall. The tip of the expansion sleeve can be understood as the front end of the expansion sleeve, i.e., the end pointing in the forward direction. The sleeve abutment wall is arranged relative to the expansion sleeve, particularly axially relative to the expansion sleeve, and especially relative to the tip of the expansion sleeve. Specifically, in the state before the expansion sleeve is expanded by the expansion body, i.e., in the pre-installed state of the anchor before installation, the sleeve abutment wall faces axially toward the expansion sleeve, particularly toward the tip of the expansion sleeve. Specifically, the sleeve abutment wall faces the rear of the anchor. The anchor is configured such that during axial displacement of the expansion body relative to the expansion sleeve in the rearward direction and / or during radial expansion of the expansion sleeve by the expansion body, the expansion sleeve (particularly its tip) can contact the sleeve abutment wall. Therefore, the sleeve abutment wall is suitable and / or configured to be abutted by the expansion sleeve, particularly axially and / or by the tip of the expansion sleeve. Specifically, the sleeve abutment wall is suitable and / or configured to be abutted by a portion of the expansion sleeve (particularly the front end portion of the expansion sleeve), particularly axially, which is bent about the longitudinal axis and / or arranged substantially perpendicular to the longitudinal axis.

[0019] Specifically, the sleeve abutment wall protrudes radially on the expansion body, and / or forms a stepped structure at the sleeve abutment wall, wherein the sleeve abutment wall forms a vertical portion of the corresponding stepped structure. The sleeve abutment wall is arranged on the side surface of the expansion body, i.e., on the side of the expansion body.

[0020] The expansion body has a recessed abutment wall on its side surface, wherein the recessed abutment wall is axially defined at its front end by a sleeve abutment wall. Thus, the sleeve abutment wall forms the front end wall of the recessed abutment wall. Specifically, the recessed abutment wall extends radially into the expansion body. The recessed abutment wall is preferably located at least partially in the convergence region of the expansion body.

[0021] The recessed bottom plate forms another wall of the abutment wall recess and / or radially defines the abutment wall recess.

[0022] The recessed base plate and the sleeve abutment wall are geometrically connected, and a transition edge is formed at the point where the recessed base plate and the sleeve abutment wall meet. Therefore, the recessed base plate and the sleeve abutment wall are adjacent to the transition edge. The transition edge is located within the recess of the abutment wall.

[0023] The lead angle is the lead angle relative to the longitudinal axis. By common definition, the lead angle can be considered as the angle between the tangent at the transition edge and a plane oriented perpendicular to the longitudinal axis.

[0024] When using the term "longitudinal axis," it should specifically refer to the longitudinal axis of the anchor bolt, which may generally coincide with the longitudinal axis of the expansion anchor. By its usual definition, "longitudinal axis" can specifically refer to an axis extending in the longitudinal direction, i.e., an axis extending along the length of a slender anchor bolt. When using the terms "radial," "axial," or "circumferential," these terms should be understood specifically relative to the longitudinal axis of the anchor bolt.

[0025] According to a preferred embodiment of the invention, the radial height of the sleeve abutment wall preferably gradually decreases toward the rear of the anchor bolt and / or toward the rear of the expansion body. Therefore, the sleeve abutment wall rises higher as it axially approaches the front end of the expansion body. This allows the expansion sleeve to gradually climb the angled sleeve abutment wall as the expansion body is pulled into the expansion sleeve, thereby further improving performance.

[0026] Particularly advantageous is that at least one sleeve abutment wall tapers towards the rear of the anchor bolt. Therefore, preferably, the sleeve abutment wall is at least generally not perpendicular to the longitudinal axis. Conversely, the radius of the expansion body gradually decreases towards the rear of the anchor bolt at the sleeve abutment wall. This allows for the creation of traversable obstacles in a particularly reliable and easily manufactured manner.

[0027] The expansion body may have a transition zone located in front of the convergence zone. In such a transition zone, the convergence of the expansion body is at least gentler compared to the convergence zone, or there may be no convergence at all. Such a transition zone can prevent the expansion sleeve from over-expanding and from applying excessive stress to the surrounding substrate under high loads. If there is no convergence at all, the transition zone may have cylindrical side surfaces, where "cylindrical" is understood in a broad sense, and the cylindrical base may be, but does not necessarily have to be, circular.

[0028] The sleeve abutment wall and / or transition edge are preferably at least partially, and preferably completely, located within the convergence zone. If a transition zone exists, the sleeve abutment wall and / or transition edge may also enter that transition zone.

[0029] Particularly preferred is that the expansion body has at least one additional abutment wall recess, preferably two or three additional abutment wall recesses. The at least one additional abutment wall recess preferably has substantially the same shape and / or function as the original abutment wall recess. The original abutment wall recess and the at least one additional abutment wall recess are preferably arranged side-by-side, i.e., in the same axial orientation.

[0030] In addition, the expansion body may be provided with additional walls, such as recessed sidewalls, which do not face the expansion sleeve axially, and / or these additional walls are not suitable for the expansion sleeve to abut against during axial displacement of the expansion sleeve, and therefore cannot be called sleeve abutment walls.

[0031] The invention will now be explained in more detail with reference to preferred exemplary embodiments, which are schematically depicted in the accompanying drawings, wherein the various features of the exemplary embodiments presented below may be implemented individually or in any combination. Attached Figure Description

[0032] Figure 1 This is a side view of the expansion anchor.

[0033] Figure 2 Is with Figure 1 Same view, but the expansion sleeve is omitted.

[0034] Figure 3 It is a magnified perspective view of the anchor bolt in the front region of the anchor bolt, including the expansion body 20.

[0035] Figure 4 It is a side view of the anchor bolt in the front region of the anchor bolt, including the expansion body 20.

[0036] Figure 5 Is with Figure 4 Same view, but all reference numerals and auxiliary lines are omitted. Detailed Implementation

[0037] The attached figure illustrates an embodiment of the expansion anchor. The anchor includes: an elongated anchor bolt 10, the elongated anchor bolt having a front end (…). Figure 2 (left end) and back end ( Figure 2 The anchor 10 consists of a right-hand side); an expansion sleeve 30 surrounding the anchor 10; and an expansion body 12 for radially expanding the expansion sleeve 30 and positioned on the anchor 10, specifically near the front end of the anchor 10. The anchor 10 has a longitudinal axis 99 extending through both the front and rear ends of the anchor 10. The longitudinal axis 99 passes through the expansion sleeve 30.

[0038] The expansion body 12 has a convergence region 23, which is designed to cause the expansion sleeve 30 to expand radially as the expansion body 12 is pulled into the expansion sleeve 30 in a rearward direction, i.e., as the expansion sleeve 30 moves forward relative to the expansion body 12 onto the expansion body 12. For this purpose, at least before the anchor is installed, the side surface of the expansion body 12 converges toward the rear of the anchor bolt 10, i.e., toward the expansion sleeve 30. In this example, the side surface of the expansion body 12 is tapered in the convergence region 23, with the convergence focus on the longitudinal axis 99 and the apex angle β at... Figure 2The example is shown below. However, this is just an example, and other convergence designs are possible.

[0039] In this example, the expansion body 12 also has a transition region 22 and a tip region 21, the transition region being located in front of and adjacent to the convergence region 23, and the tip region being located in front of and adjacent to the transition region 22. In the transition region 22, the backward convergence is smaller than that in the convergence region 23, or even zero, but preferably non-reverse convergence, i.e., not forward convergence. In this example, there is no convergence in the convergence region 23, i.e., zero, and the expansion body 12 has cylindrical side surfaces in the convergence region 23, particularly cylindrical with a circular bottom surface. In the tip region 21, the side surfaces of the expansion body 12 converge toward the front end of the anchor.

[0040] Anchor bolt 10 has a neck 25 located near and behind expansion body 12. At least before anchor installation, expansion sleeve 30 at least partially surrounds the neck 25. The diameter of anchor bolt 10 can be minimal at the neck 25. In this embodiment, anchor bolt 10 has a plurality of axially extending grooves within its neck 25, and expansion sleeve 30 has corresponding axially extending ridges that engage with the axially extending grooves, but this is merely an example.

[0041] In this embodiment, the anchor is a stud type. The anchor bolt 10 has (i.e., at the rear end of the neck 25) a forward-facing shoulder 17 for axially engaging with the expansion sleeve 30 and for advancing the expansion sleeve 30 forward. In the present case, the expansion body 12 and the anchor bolt 10 are, for example, integral, but this is only an example, and a non-integral design is also feasible.

[0042] In the rear region of the anchor bolt 10, the anchor bolt 10 is provided with a tension introduction structure 18, which is in the form of an external thread on the anchor bolt 10.

[0043] The expansion sleeve 30 is provided with a plurality of slits 36' (four in the present case, as an example, where only a single slit is in Figure 1 As can be seen in the image, these slits originate from the front end of the expansion sleeve 30 and extend toward the rear end of the expansion sleeve 30.

[0044] An abutment wall recess 66 is provided on the side surface of the expansion body 12. This abutment wall recess provides a recess within the expansion body 12 and is radially accessible from the outside of the expansion body 12. The abutment wall recess 66 extends at least within the convergence region 23 of the expansion body 12. In this embodiment, the abutment wall recess 66 extends only within the expansion body 12, but in other embodiments, it may also extend into the neck 25.

[0045] The abutment wall recess 66 is defined radially by the recess base plate 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 axially toward the expansion sleeve 30, i.e., the sleeve abutment wall faces rearward. The sleeve abutment wall 60 may be arranged 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.

[0046] The sleeve abutment wall 60 forms a preferred traversable abutment for the front end (i.e., for the tip of the expansion sleeve 30). When the expansion body 12 is pulled into the expansion sleeve 30, the expansion sleeve 30 is intended to abut against the sleeve abutment wall 60, thereby causing the expansion sleeve 30 to move forward relative to the expansion body 12.

[0047] A transition edge 69 is formed where the recessed bottom plate 62 meets the sleeve abutment wall 60. In other words, the transition edge 69 is adjacent to both the recessed bottom plate 62 and the sleeve abutment wall 60.

[0048] The transition edge 69 is specifically arranged with a lead angle α relative to a plane 91 arranged perpendicular to the longitudinal axis 99. This lead angle α is substantially constant along the entire transition edge 69. In this embodiment, the lead angle is approximately 10°.

[0049] The radial (relative to longitudinal axis 99) height of the sleeve abutment wall 60 is not constant. Instead, the height decreases toward the rear of the anchor bolt 10.

[0050] The expansion body 12 is provided with at least one additional abutment wall recess (three additional abutment wall recesses in this embodiment; as an example, only two additional abutment wall recesses are visible in the figures, denoted as 66' and 66''' respectively). Each of these additional abutment wall recesses 66', 66''' has a shape substantially the same as that of the abutment wall recess 66. In particular, each of these additional abutment wall recesses 66', 66''' is radially defined by an additional recess base plate, and at its respective front end, each additional abutment wall recess is axially defined by an additional sleeve abutment wall facing the expansion sleeve, i.e., rearward. An additional transition edge is formed where the additional recess base plate meets the additional sleeve abutment wall. At least one additional sleeve abutment wall and sleeve abutment wall 60 are positioned side by side, in the same location along the longitudinal axis 99, and do not overlap in the circumferential direction.

[0051] Anchors can be installed as follows: In the first step, the anchor is introduced into the hole in the base, with the front end being introduced first.

[0052] Subsequently, the expansion body 12 is pulled into the front end region of the expansion sleeve 30, meaning that the expansion sleeve 30 is displaced forward relative to the expansion body 12 and covers it. In this embodiment, this is achieved by pulling the anchor bolt 10 and the expansion body 12 together backward, specifically by tightening a nut (not shown) provided on the tension introduction structure 18 of the anchor bolt 10. Pulling the expansion body 12 into the expansion sleeve 30 causes the expansion sleeve 30 to expand radially, thereby locking the anchor in the base.

[0053] When the expansion body 12 is pulled sufficiently deep into the expansion sleeve 30, the expansion body will eventually touch the sleeve abutment wall 60 with its tip. This may result in axial interlocking of the expansion sleeve 30 and the expansion body 12 at the sleeve abutment wall 60, thus altering the expansion mechanism. This may, in turn, lead to increased pull-out resistance without causing excessive stress on the substrate. Due to the non-perpendicular lead angle α and the gradual increase in radial height of the sleeve abutment wall 60 towards the front end of the anchor bolt 10, the engagement of the expansion sleeve 30 with the sleeve abutment wall 60 can be expected to be a gradual process, resulting in a gradual change in anchoring characteristics.

Claims

1. An expansion anchor, the expansion anchor comprising: - Anchor bolt (10), the anchor bolt having a longitudinal axis (99). - An expansion sleeve (30), the expansion sleeve surrounding the anchor bolt (10), and - An expansion body (12), the expansion body being located in the front region of the anchor bolt (10), wherein the expansion body (12) has a convergence area (23) for expanding the expansion sleeve (30), wherein the expansion body (12) is provided with an abutment wall recess (66), wherein the abutment wall recess (66) is defined by a sleeve abutment wall (60) axially facing the expansion sleeve (30) to provide abutment for the expansion sleeve (30) as the expansion sleeve moves axially toward the sleeve abutment wall (60), and wherein the abutment wall recess (66) is further defined by a recess bottom plate (62), wherein a transition edge (69) is formed between the recess bottom plate (62) and the sleeve abutment wall (60). Its features are, - The transition edge (69) extends with a lead angle α, wherein at least in a portion of the transition edge (69), the following applies to the lead angle α: 4°≤α≤30°。 2. The expansion anchor according to claim 1, Its features are, -At least in a portion of the transition edge (69), the following applies to the lead angle α: 4°≤α≤16°。 3. The expansion anchor according to any one of the preceding claims, Its features are, -At least in a portion of the transition edge (69), the following applies to the lead angle α: 9°≤α≤11°。 4. The expansion anchor according to any one of the preceding claims, Its features are, - Throughout the entire transition edge (69), the following applies to the lead angle α: 4°≤α≤30°, or 4°≤α≤16°, or 9°≤α≤11°。 5. The expansion anchor according to any one of the preceding claims, Its features are, The transition edge (69) is approximately constant along its extended lead angle α throughout the entire transition edge (69).

6. The expansion anchor according to any one of the preceding claims, Its features are, The radial height of the sleeve abutment wall (60) gradually decreases toward the rear of the anchor bolt (10).

7. The expansion anchor according to any one of the preceding claims, Its features are, At least one sleeve abutment wall (60) tapers toward the rear of the anchor bolt (10).

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