SPREADING ANCHOR AND METHOD FOR SPREADING THE SPREADING ANCHOR

Description

[0001] The invention relates to an expansion anchor having the features of the preamble of claim 1 and a method for expanding the expansion anchor having the features of the preamble of claim 7.

[0002] German patent application DE 31 24 685 A1 discloses an expansion anchor comprising an anchor shaft, a frustoconical expansion body integral with the anchor shaft, and an expansion sleeve slidable on the anchor shaft. The expansion sleeve is divided into expansion tabs by longitudinal slots open at a front end facing the expansion body. These tabs extend along a limited axial section of the expansion sleeve in a longitudinal direction. For example, by screwing a nut onto a threaded section of the anchor shaft, the expansion tabs of the expansion sleeve can be slid onto the expansion body and are then expanded by the expansion body.

[0003] The patent application DE 10 2011 007 570 A1 discloses an expansion anchor comprising an anchor bolt, an expansion sleeve and at least one eccentric geometry, wherein the expansion sleeve can be expanded by means of a rotational movement of the anchor bolt.

[0004] The object of the invention is to improve the spreading behavior of an expansion anchor and to propose a method for spreading the expansion anchor.

[0005] This problem is solved according to the invention by the features of claims 1 and 7. The expansion anchor according to the invention comprises an expansion body and an expansion sleeve. The expansion sleeve is divided into expansion tabs by longitudinal slots, the longitudinal slots preferably being open at a front end facing the expansion body, so that the expansion tabs are free at their front ends facing the expansion body and thus form a cantilever. The longitudinal slots can run parallel to the axis or at an angle to the axis parallels of the expansion sleeve, the angle being able to change along the length of the longitudinal slots. For example, the longitudinal slots can be helical, wavy, or zigzag in shape.

[0006] The expansion body has an expansion surface for each expansion tab, with a first slope in a longitudinal or axial direction of the expansion anchor, expansion body, expansion sleeve, or anchor shaft of the expansion anchor. This allows the expansion tabs of the expansion sleeve to be slid onto the expansion surface of the expansion body by axial movement relative to the expansion body. "Slope" here refers to an increase in the radial distance of the expansion surfaces from a longitudinal axis of the expansion body in one direction, for example, longitudinally or circumferentially. When the expansion tabs are slid onto the expansion surfaces, the slope of the expansion surfaces forces the expansion tabs radially apart, which can be understood as the expansion of the expansion tabs, the expansion sleeve, or the expansion anchor. This expansion allows the expansion anchor to be anchored in an anchor hole.

[0007] In addition to the first slope in the longitudinal or axial direction, the spreading surfaces of the expanding body of the expansion anchor according to the invention have a second slope in a circumferential direction, which is superimposed on the first slope. This means that the radial distance of the spreading surfaces from the longitudinal axis of the expanding body increases not only in the axial direction but also in the circumferential direction. The expanding tabs can therefore be expanded not only by axial displacement relative to the expanding body, but also by rotation relative to the expanding body, or by a combination of displacement and rotation when the expanding tabs are in contact with the expanding surfaces. The expanding action is achieved in particular by an axial movement of the expanding body relative to the expanding sleeve, with a rotational movement superimposed on the axial movement.The direction of rotation of the spreading body in relation to the spreading tabs in the circumferential direction, which spreads the spreading tabs, is hereinafter also referred to as the "spreading direction".

[0008] The design according to the invention transforms an unwanted rotation of the spreading body when the expanding anchor according to the invention is clamped against an attachment, for example when screwing a nut onto an anchor shaft connected to the expanding body, into an additional spreading action, which prevents further rotation.

[0009] The spreading body can, for example, be designed similarly to a truncated cone, with a circumferential surface divided into segments that form the spreading surfaces, each exhibiting the first and second slopes. The height of the truncated cone is, in particular, parallel to or identical with the longitudinal axis. The radial distance of the spreading surfaces from the longitudinal axis of the spreading body increases both axially and circumferentially from one segment to the next, i.e., from one spreading surface to the next circumferentially. A kind of step or ledge is arranged between the spreading surfaces. The spreading surfaces can be considered spatially separated and distinct.

[0010] The spreading body can, for example, be designed similarly to a truncated pyramid, with the lateral surfaces of the truncated pyramid forming the spreading surfaces. The spreading surfaces can be flat or circumferentially curved. They also exhibit a slope in both the axial and circumferential directions, meaning their radial distance from the longitudinal axis of the spreading body increases in both directions.

[0011] In the axial direction, the spreading surfaces can be flat, convex, or concave. The invention is not limited to the described shapes of the spreading body.

[0012] Preferably, the expansion anchor according to the invention has an anchor shaft with a screw thread that is rotationally fixed to the expansion body. A nut can be screwed onto this thread to slide the expansion sleeve towards the expansion body, i.e., to expand it and / or to fasten an attachment mounted on the anchor shaft. The rotational rigidity can be achieved through positive locking, frictional locking, or by a one-piece construction. In particular, the expansion body is rotationally and axially fixed to the anchor shaft, especially due to its one-piece construction. The thread pitch of the screw thread is oriented such that a torque exerted on the anchor shaft by the nut through friction on the screw thread when it is screwed towards the expansion body acts on the expansion body in the direction of expansion rotation.

[0013] One embodiment of the invention provides a rotational support for the expansion sleeve on the expansion body, limiting the rotation of the expansion sleeve relative to the expansion body in the opposite direction of expansion. The rotational support can be formed by steps at a transition from one expansion surface to an adjacent expansion surface, against which the expansion tabs come into contact when the expansion sleeve is rotated relative to the expansion body in the opposite direction of expansion. The steps can, for example, lie in axial planes to the longitudinal axis, with the slope of the step running radially to the longitudinal axis; however, they can also, for example, run obliquely to axial planes or be curved. The rotational support prevents the expansion sleeve from rotating backwards in the opposite direction of expansion beyond a starting position in which the expansion tabs are not expanded, or at least not by rotation relative to the expansion body.

[0014] The slope of the expansion surfaces is, for example, approximately 10° in the axial direction (= first slope) and, for example, approximately 0.068 times the nominal diameter of the expansion anchor in the circumferential direction over the circumference of each expansion surface (= second slope). The nominal diameter is, for example, the diameter of the screw thread of the anchor shaft, the outer diameter of the unexpanded expansion sleeve, or the expansion sleeve outside the expansion lugs, or a diameter at a larger diameter end of the expansion body. "Approximately" means a tolerance of, for example, 10% or 20%, that is, the first slope (α) of the spreading surfaces in the axial direction is, for example, between 8° and 12°, in particular between 9° and 11°, and the second slope (P) in the circumferential direction is between 0.055 and 0.08 times, and in particular between 0.06 and 0.075 times, the nominal diameter.

[0015] To ensure that the unexpanded expansion sleeve has sufficient hold in an anchor hole to allow the expansion body to be drawn between the expansion tabs and / or to rotate between the expansion tabs for expansion, one embodiment of the invention provides one or more anti-rotation and anti-slide tabs that project obliquely outwards from a base body of the expansion sleeve, for example, in the axial and / or circumferential direction. In the unexpanded state of the expansion sleeve, the base body has a cylindrical shape. The anti-rotation and anti-slide tab(s) project radially outwards beyond a lateral surface or circumferential surface of the base body of the expansion sleeve in the area of ​​the anti-rotation and anti-slide tab(s), so that they bear against a wall of the anchor hole and hold the unexpanded expansion sleeve in the anchor hole.

[0016] To anchor the expansion anchor according to the invention, the inventive method provides for inserting the expansion anchor, with the expansion body leading, into an anchor hole in an anchor base and expanding it within the anchor hole. For this purpose, the expansion sleeve is axially displaced within the anchor hole relative to the expansion body, meaning that the expansion sleeve is moved towards the expansion body and / or the expansion body is moved towards the expansion sleeve, so that the expansion tabs come into contact with the expansion surfaces and are spread open. Furthermore, the expansion body can be rotated circumferentially relative to the expansion sleeve in the expansion direction, particularly during and / or after the axial movement of the expansion sleeve relative to the expansion body.

[0017] One embodiment of the method according to the invention provides that a nut is turned onto the screw thread of the anchor shaft, so that it moves in the direction of the expansion body located in the anchor hole. In particular, the expansion sleeve can be moved axially relative to the expansion body and expanded. Due to friction between the nut and the screw thread, the nut exerts a torque on the anchor shaft as it rotates, which the anchor shaft transmits to the expansion body, resulting in movement in the expansion direction. This torque thus increases or intensifies the expansion of the expansion tabs due to the second slope of the expansion surfaces in the circumferential direction. This rotation in the expansion direction can occur, in particular, simultaneously with the axial movement of the expansion body relative to the expansion sleeve or after the axial movement.

[0018] The anchor hole is, for example, a drilled, for example cylindrical, hole in an anchor base made of, for example, concrete or stone. If the anchor hole is a blind hole, one embodiment of the invention provides for placing the expanding body onto the base of the hole for expansion, wherein the base of the hole forms a kind of axial abutment for the front end of the expanding body, which rests against the base of the hole. This axially holds the expanding body when the expanding sleeve is pushed in its direction and the expanding tabs are slid onto the expanding surfaces of the expanding body.

[0019] In embodiments of the invention, the anchor hole can have an undercut into which the expanding tabs are spread, so that the expanding anchor is secured in the anchor hole by frictional locking and by positive locking through the undercut.

[0020] One embodiment of the invention provides for rotating the spreading body in the spreading direction relative to the spreading sleeve to spread the spreading tabs. Spreading is possible either solely by rotating the spreading body relative to the spreading sleeve or by rotating it in addition to the axial movement. A torque for rotating the spreading body can be applied to the anchor shaft, which is rotationally fixed to the spreading body.

[0021] The features and combinations of features, embodiments, and configurations of the invention mentioned above in the description, as well as the features and combinations of features mentioned below in the figure description and / or drawn in a figure, are not only usable in the combinations specified or drawn, but also in any other combination or individually. Embodiments of the invention are possible that do not have all the features of a dependent claim. Individual features of a claim can also be replaced by other disclosed features or combinations of features. Embodiments of the invention are possible that do not have all the features of the exemplary embodiment(s), but rather any part of the characterized features of an exemplary embodiment, possibly in combination with one, several, or all features of one or more further exemplary embodiments.

[0022] The invention is explained in more detail below with reference to an embodiment illustrated in the drawing. The drawing shows: Figure 1 shows a first embodiment of an expansion anchor according to the invention; Figure 2 shows an expansion body of the expansion anchor made of Figure 1 in a larger view; Figure 3 a second embodiment of an expansion anchor according to the invention; and Figure 4 an end view of a front end of the expansion anchor made of Figure 3 .

[0023] The in Figure 1The illustrated expansion anchor 1 according to the invention comprises an anchor shaft 2, an expansion body 3, and an expansion sleeve 4. At a rear end furthest from the expansion body 3, the anchor shaft 2 has a screw thread 5. At an axial distance from the expansion body 3, the anchor shaft 2 has an annular step serving as an axial abutment 6 for the expansion sleeve 4. The expansion sleeve 4 is arranged to be axially displaceable on the anchor shaft 2 between the expansion body 3 and the abutment 6.

[0024] The expanding sleeve 4 is stamped from a flat sheet of metal or, for example, separated from the flat sheet of metal by laser cutting and bent into the cylindrical tube-shaped sleeve.

[0025] The expanding sleeve 4 has longitudinal slots 7 that divide it into expanding tabs 8. These tabs extend longitudinally along the sleeve 4 and are arranged side by side circumferentially. The longitudinal slots 7 begin at a front end of the expanding sleeve 4 and extend—in this embodiment—over approximately two-thirds of the axial length of the sleeve 4. The "front end" here refers to the end of the expanding tabs 8 and the expanding sleeve 4 facing the expanding body 3. In this embodiment, the longitudinal slots 7 run parallel to the axis; however, they can also be arranged, for example, in a helical, wavy, or zigzag pattern (not shown).

[0026] The expansion body 3 has a shape similar to a truncated cone and is integrally connected at its smaller diameter end to the anchor shaft 2, which has the same diameter as the smaller diameter end of the expansion body 3. Due to its integral connection, the expansion body 3 is rotationally and axially fixed to the anchor shaft 2.

[0027] Unlike a truncated cone, the expanding body 3 of the expanding anchor 1 according to the invention does not have a circumferentially continuous surface, but rather the expanding body 3 has a separate expanding surface 10 for each expanding tab 8 of the expanding sleeve 4, which extends over a part of the circumference. The expanding surfaces 10 can be considered spatially separated, individual expanding surfaces 10. The expanding surfaces 10 have – like a truncated cone – a first slope (α) in the axial direction and – unlike a truncated cone – a second slope (P) in the circumferential direction. Figure 2The second slope (P) is superimposed on the first slope (α). This means that the radial distance of the expanding surfaces 10 from a longitudinal axis of the expanding body 3 changes both axially and circumferentially. The radial distance of the expanding surfaces 10 from the longitudinal axis of the expanding body 3 increases forwards towards a front end 12 of the expanding body 3 and increases axially counterclockwise, i.e., to the left, when viewed towards the rear end of the anchor shaft 2. This applies if the screw thread 5 on the anchor shaft 2 is a right-hand thread. For a left-hand thread, the second slope (P) of the expanding surfaces 10 would be opposite in the circumferential direction. The "front end" 12 of the expanding body 3 is the end of the expanding body 3 with the larger diameter, which faces away from the anchor shaft 2.

[0028] In the exemplary embodiment, the spreading surfaces 10 have a first slope (α) of 10° in the axial direction towards the front end 12 of the spreading body 3, which is also a front end 12 of the spreading anchor 1, and a second slope (P) in the circumferential direction opposite to an expanding rotation direction of 0.068 times the outer diameter of the screw thread 5. Deviations of ±1° or ±2° or of ±10% or ±20% are possible.

[0029] In the circumferential direction, the spreading surfaces 10 rise such that a moment exerted by a nut (not shown), which is screwed onto the threaded end 5 of the anchor shaft 2 in the direction of the spreading body 3, exerts a moment on the anchor shaft 2 through friction with the threaded end 5. This moment acts on the spreading body 3, which is rotationally fixed to the anchor shaft 2, in the direction of spreading the spreading tabs 8. This direction of rotation is also referred to here as the "spreading rotation direction".

[0030] In the circumferential direction, the spreading surfaces 10 each transition into an adjacent spreading surface 10 by a step. These steps, which in the exemplary embodiment are located in axial planes of the spreading body 3, form rotational abutments 13 for the spreading sleeve 4. These abutments limit rotation of the spreading sleeve 4 relative to the spreading body 3 by the contact of longitudinal edges 11 of the spreading tabs 8 against an expanding rotation direction. Due to their shape and arrangement, the spreading surfaces 10 can be considered spatially separated and distinct. In the circumferential direction, the spreading surfaces 10 have a second slope (P) along their circumferential extent from step to step. The steps forming the rotational abutments 13 have, in the radial direction of the spreading body 3, the height of the second slope (P) of the spreading surfaces 10 in the circumferential direction.

[0031] To spread the spreading tabs 8, i.e., to radially force them apart, the spreading body 3 is pulled between the spreading tabs 8, or conversely, the spreading tabs 8 are pushed onto the spreading body 3, and / or the spreading body 3 is rotated in the spreading direction relative to the spreading tabs 8 abutting its spreading surfaces 10. The "spreading direction" refers to the direction of rotation of the spreading body 3 relative to the spreading sleeve 4 or the spreading tabs 8, which, due to the second slope (P) of the spreading surfaces 10 of the spreading body 3 in the circumferential direction, forces the spreading tabs 8 radially apart, i.e., spreads them open. The spreading tabs 8 can therefore be spread open both by an axial movement relative to the spreading body 3 and by a rotation in the spreading direction relative to the spreading body 3.A combination of axial movement and rotation, which can occur simultaneously or at different times, increases or intensifies the spreading.

[0032] In the exemplary embodiment, the front edges 14 of the spreading tabs 8 are inclined, although this is not essential for the invention. The front edges 14 are defined as the edges of the spreading tabs 8 facing the spreading body 3.

[0033] Behind the expanding tabs 8, the expanding sleeve 4 has anti-rotation and anti-slide tabs 15, which project obliquely outwards at an acute angle to the longitudinal axis of the expanding sleeve 4. The anti-rotation and anti-slide tabs 15 project radially outwards over a cylindrical surface of the expanding sleeve 4 in the area where they are located. In an anchor hole (not shown), the anti-rotation and anti-slide tabs 15 abut a hole wall and hold the expanding sleeve 4 against displacement and rotation within the anchor hole, allowing the expanding body 3 to be drawn between the expanding tabs 8 and rotated between them.

[0034] In the following description of the Figures 3 and 4 will be for with Figures 1 and 2 matching elements, same reference numbers as in Figures 1 and 2 used.

[0035] The in Figure 3The expansion anchor 1 according to the invention is designed for anchoring in an anchor hole (not shown), which is axially short, has a conical undercut, and is designed as a blind hole, for example in a facade panel made of stone or a comparable material. The expansion anchor 1 has an anchor shaft 2 with a screw thread 5 at a rear end and an expansion body 3 at a front end, which is rotationally and axially fixed, namely, in the exemplary embodiment, integrally with the anchor shaft 2. The expansion body 3 is axially short, namely preferably not longer axially than the outer diameter of the screw thread 5.

[0036] The expanding body 3 of the expanding anchor 1 made of Figure 3The expanding body 3 has a truncated pyramid shape. It widens towards a front end 12, furthest from the screw thread 5. It has a number – six in this embodiment – ​​of planar expanding surfaces 10, which diverge obliquely towards the front end 12 with a first slope (α). In a circumferential direction, the expanding surfaces 10 are arranged as shown in the end view of the Figure 4 The spreading surfaces 10 are tilted and arranged at an angle to imaginary tangents, so that they also have a second slope (P) in the circumferential direction. The spreading surfaces 10 with longitudinally extending steps 16 adjoin a circumferentially adjacent spreading surface 10, as shown in Figure 4The spreading surfaces 10 can be seen running obliquely to the axial planes of the spreading body 3. They are spatially separated and distinct from one another. Instead of flat spreading surfaces 10, convexly curved spreading surfaces 10 are also possible in the circumferential direction (not shown). In the axial direction, the spreading surfaces 10 can be concave or convexly curved instead of flat (not shown).

[0037] A spreading sleeve 4 is slidably arranged on the anchor shaft 2 in the direction of the spreading body 3. At a front end facing the spreading body 3, the spreading sleeve 4 has recesses 17, forming spreading tabs 8. The spreading body 3 has a spreading surface 10 for each spreading tab 8. At the rear ends of the spreading tabs 8, the spreading sleeve 4 has a circumferential groove 18 on its outer surface, which facilitates outward pivoting, i.e., spreading open, of the spreading tabs 8.

[0038] In the circumferential direction, the expanding sleeve 4 can be closed; in the exemplary embodiment, it has a continuous longitudinal slot 7 because it is bent from an originally flat sheet metal to form the expanding sleeve 4.

[0039] The expansion anchor 1 is used for anchoring, i.e., fastening in the not shown, conically undercut and blind-hole anchor hole in, for example, the not shown facade panel forming an anchor base. Figures 3 and 4The expanding body 3 is inserted into the anchor hole until it rests on the bottom of the anchor hole. The expanding sleeve 4 is then pushed along the anchor shaft 2 towards the expanding body 3, so that the expanding tabs 8 of the expanding sleeve 4 are pushed onto the expanding surfaces 10 of the expanding body 3. To push the expanding sleeve 4 along the anchor shaft 2, a tubular tool (not shown) can be placed behind the expanding sleeve 4 onto the anchor shaft 2, and the expanding sleeve 4 can be pushed towards the expanding body 3, for example, by striking the tool with a hammer. Due to the first slope α of the expanding surfaces 10 in the axial direction, the expanding surfaces 10 press the expanding tabs 8 radially apart as they are pushed onto the expanding surfaces 10, i.e., the expanding tabs 8 are spread open.By spreading the expansion tabs 8 engage in the conical undercut of the anchor hole (not shown), whereby the expansion anchor 1 is held in the anchor hole in, for example, the facade panel by positive locking and, if necessary, additionally by force locking (friction locking).

[0040] After expansion, the tubular tool (not shown) is removed from the anchor shaft 2. An attachment (not shown) with a through-hole is placed onto the anchor shaft 2, which protrudes from the facade panel. A nut (also not shown) is then screwed onto the threaded hole 5 of the anchor shaft 2. The nut is tightened so that it clamps the attachment (not shown) against a rear end of the expansion sleeve 4 or against the facade panel (not shown). This also clamps the expansion anchor 1 axially in the undercut of the anchor hole. As the nut is tightened, the expansion sleeve 4 is pushed further towards the expansion body 3, and the expansion tabs 8 are pushed further onto the expansion surfaces 10, thereby increasing the expansion.

[0041] When the nut (not shown) is turned on the screw thread 5 of the anchor shaft 2, and especially when the nut is tightened, the nut exerts a moment on the anchor shaft 2 through friction with the screw thread 5. This moment is transmitted by the anchor shaft 2 to the expansion body 3, which is non-rotatably connected to it. This moment is directed such that the expansion body 3 rotates in the expansion sleeve 4, or between the expansion tabs 8, such that the expansion tabs 8 of the expansion sleeve 4 move away from the steps 16 on the expansion surfaces 10 of the expansion body 3 towards the outer ends of the expansion surfaces 10. That is, the expansion tabs 8 move in the direction of the second slope P of the expansion surfaces 10 in the circumferential direction, where they are further expanded. This strengthens the anchorage of the expansion anchor 1 in the undercut anchor hole.

[0042] In the expansion anchors 1 according to the invention, the spreading of the expansion tabs 8, both by the axial movement of the expansion sleeve 4 in relation to the expansion body 3 and by the rotation of the expansion sleeve 4 in relation to the expansion body 3, enables the expansion of the expansion tabs 8 with a relatively short axial path of the expansion sleeve 4 in relation to the expansion body 3, or it prevents the expansion anchor 1 from rotating in the borehole when the nut is screwed on. Reference symbol list

[0043] First pitch in axial direction; Second pitch in circumferential direction; 1 Expansion anchor; 2 Anchor shaft; 3 Expansion body; 4 Expansion sleeve; 5 Screw thread; 6 Abutment; 7 Longitudinal slot; 8 Expansion tab 9 free 10 Spreading surface 11 Longitudinal edge 12 Front end of the spreader body 3 13 Rotation stop 14 Front edge of the spreader tabs 8 15 Rotation and sliding locking tab 16 Step 17 Recess 18 Groove

Claims

1. Expansion anchor having an expansion body (3) which has an expansion surface (10) with a first pitch (α) in an axial direction, and having an expansion sleeve (4) on which expansion tabs (8) are formed by longitudinal slots (7) or recesses (17), which can be brought between the expansion tabs (8) onto the expansion surface (10) of the expansion body (3) by moving the expansion body (3) and can thus be expanded, characterized in that the expansion body (3) has a spatially offset, separate expansion surface (10) for each expansion tab (8) and in that the expansion surfaces (10) have a second pitch (P) in a circumferential direction which is superimposed on the first pitch (α), so that the expansion tabs (8) of the expansion sleeve (4) can also be expanded by rotating the expansion sleeve (4) with respect to the expansion body (3).

2. Expansion anchor according to claim 1, characterized in that the expansion anchor (1) has an anchor shaft (2) which is rotationally fixed to the expansion body (3) and has a screw thread (5), the thread pitch of which is directed such that a screwing movement on the screw thread (5) in the direction of the expansion body (3) generates, due to friction on the screw thread (5), a torque on the anchor shaft (2) which expands the expansion tabs (8).

3. Expansion anchor according to claim 1 or 2, characterized in that the expansion body (3) has a rotary abutment (13) for the expansion sleeve (4), which limits the rotation of the expansion sleeve (4) with respect to the expansion body (3) counter to an expansion rotation direction.

4. Expansion anchor according to claim 3, characterized in that the expansion body (3) has a step at a transition from one expansion surface (10) to an adjacent expansion surface (10), which step forms the rotary abutment (13) for the expansion sleeve (4).

5. Expansion anchor according to one or more of the preceding claims, characterized in that the expansion surfaces (10) have a first pitch (α) of 10° in the axial direction and / or a second pitch (P) of 0.068 times a nominal diameter of the expansion anchor (1) in the circumferential direction.

6. Expansion anchor according to one or more of the preceding claims, characterized in that the expansion sleeve (4) has a rotation and sliding locking tab (15) which protrudes radially outwards beyond a lateral surface of a base body of the expansion sleeve (4) in the region of the rotation and sliding locking tab (15).

7. Method for expanding an expansion anchor according to one or more of claims 1 to 6, characterized in that the expansion anchor (1) is introduced with the expansion body (3) first into an anchor hole in an anchor base and that the expansion sleeve (4) in relation to the expansion body (3) is moved axially in the direction of the expansion body (3), so that the expansion tabs (8) reach the expansion surfaces (10) of the expansion body (3), which have the first pitch (a), and are expanded by the expansion surfaces (10) due to the axial movement of the expansion body (3) relative to the expansion sleeve (4).

8. Method according to claim 7, characterized in that the anchor hole is a blind hole, on the hole base of which the expansion body (3) sits when the expansion tabs (8) are expanded.

9. Method according to claim 7 or 8, characterized in that the expansion anchor (1) has an anchor shaft (2) which is rotationally fixed to the expansion body (3) and which has a screw thread (5), and that a nut on the screw thread (5) of the anchor shaft (2) is rotated in the direction of the expansion body (3) such that thread friction between the nut and the screw thread (5) of the anchor shaft (2) causes a torque on the anchor shaft (2) which additionally expands the expansion tabs (8) of the expansion sleeve (4) on the expansion surfaces (10) of the expansion body (3) by the second pitch (P) of the expansion tabs (8) in the circumferential direction of the expansion body (3).

10. Method according to one or more of claims 7 to 9, characterized in that the anchor hole has an undercut in which the expansion tabs (8) are expanded.

11. Method according to one or more of claims 7 to 10, characterized in that the expansion body (3) is rotated in the expansion rotation direction in relation to the expansion sleeve (4) to expand the expansion tabs (8).