EXPANSION ANCHOR WITH DOUBLE COATING INCLUDING A ZINC FLAKE AND/OR ALUMINUM FLAKE LAYER

Abstract

An expansion anchor includes an anchor bolt, an expansion sleeve as a first element where the expansion sleeve surrounds the anchor bolt, a wedge body for expanding the expansion sleeve as a second element where the wedge body is disposed on the anchor bolt, and a double coating disposed on one of the first and second elements at least in an area of contact with the other of the first and second elements. The one of the first and second elements on which the double coating is disposed is carbon steel. The double coating has a zinc flake and/or an aluminum flake top layer and a hot dip galvanized zinc, a ZnNi, or a ZnFe base layer that is covered by the zinc flake and/or the aluminum flake top layer.

Claims

1.-8. (canceled)

9. An expansion anchor, comprising: an anchor bolt; an expansion sleeve, wherein the expansion sleeve is a first element and wherein the expansion sleeve surrounds the anchor bolt; a wedge body for expanding the expansion sleeve, wherein the wedge body is a second element and wherein the wedge body is disposed on the anchor bolt; and a double coating disposed on one of the first and second elements at least in an area of contact with the other of the first and second elements; wherein the one of the first and second elements on which the double coating is disposed is comprised of carbon steel; wherein the double coating comprises a zinc flake and/or an aluminum flake top layer and a hot dip galvanized zinc, a ZnNi, or a ZnFe base layer that is covered by the zinc flake and/or the aluminum flake top layer.

10. The expansion anchor according to claim 9, wherein the double coating is disposed on second element.

11. The expansion anchor according to claim 10, wherein the expansion sleeve is comprised of steel.

12. The expansion anchor according to claim 11, wherein the expansion sleeve is comprised of stainless steel.

13. The expansion anchor according to claim 10, wherein the wedge body and the anchor bolt are integral and wherein the double coating extends to the anchor bolt.

14. The expansion anchor according to claim 10, wherein the wedge body and the anchor bolt are integral and wherein the double coating covers all of a surface of the wedge body and a surface of the anchor bolt.

15. The expansion anchor according to claim 9, wherein the zinc flake and/or the aluminum flake top layer is uncoated at least in the area of contact.

16. A method for using the expansion anchor according to claim 9, comprising the steps of: moving the wedge body rearwards relative to the expansion sleeve and expanding the expansion sleeve by the moving.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 shows a longitudinal sectional view of a first embodiment of an expansion anchor that is installed in a concrete substrate;

[0030] FIG. 2 shows a magnified schematic view of the expansion anchor of FIG. 1, in the front region of the anchor, namely in the region marked with a circle in FIG. 1;

[0031] FIG. 3 shows a longitudinal sectional view of an expansion anchor in a modification of the embodiment of FIGS. 1 and 2, the expansion sleeve being omitted for the sake of clarity;

[0032] FIG. 4 shows a longitudinal sectional view of a third embodiment of an expansion anchor that is installed in a concrete substrate; and

[0033] FIG. 5 shows a magnified schematic view of the expansion anchor of FIG. 4, in the front region of the anchor, namely in the region marked with a circle in FIG. 4.

DETAILED DESCRIPTION OF THE DRAWINGS

[0034] FIGS. 1 and 2 show a first embodiment of an inventive expansion anchor. The expansion anchor comprises an elongate anchor bolt 10 defining a longitudinal axis 99, an expansion sleeve 30, which surrounds the anchor bolt 10, and a wedge body 12 for the expansion sleeve 30 provided on the anchor bolt 10, namely in the vicinity of the front end of the anchor bolt 10.

[0035] The wedge body 12 has a converging zone 23 intended for radially expanding the expansion sleeve 30 when the wedge body 12 is drawn into the expansion sleeve 30 in the rearwards direction 101, i.e., when the wedge body 12 is moved rearwards relative to the expansion sleeve 30 into the expansion sleeve 30. For this purpose, in the converging zone 23, the lateral surface of the wedge body 12 converges towards the rear of the anchor. In the present example, the lateral surface of the wedge body 12 is conical in the converging zone 23, with a focus of convergence on the longitudinal axis 99. However, this is merely an example and other converging designs are also possible.

[0036] In the present example, the wedge body 12 also has a transition zone 22, which is located forwards of and adjacent to the converging zone 23, and a tip zone 21, which is located forwards of and adjacent to the transition zone 22. In the transition zone 22, the rearward convergence is smaller as compared to the converging zone 23 or the rearward convergence is even zero, but preferably not reverse, i.e., it is not a forward convergence. In the present example, convergence is absent, i.e., zero, in the converging zone 23 and the wedge body 12 has a cylindrical lateral surface in the converging zone 23, in particular cylindrical with a circular base. In the tip zone 21, the lateral surface of the wedge body 12 converges towards the front end of the anchor.

[0037] The anchor bolt 10 has a neck 25, which is located adjacent to and rearwards of the wedge body 12, and in which the anchor bolt 10 has constant cross section. The expansion sleeve 30 surrounds this neck 25, at least before installation the anchor. At the neck 25, the diameter of the anchor bolt 10 can be minimal.

[0038] In the present embodiment, the anchor is of the wedge type. The anchor bolt 10 has, at the rearward end of the neck 25, a shoulder 17 facing forwards for axially engaging the expansion sleeve 30 and for advancing the expansion sleeve 30 forwards. The wedge body 12 is connected to the anchor bolt 10 in an axially fixed manner and in the present case, the wedge body 12 is, by way of example, integral with the anchor bolt 10.

[0039] In a rear region of the anchor bolt 10, the anchor bolt 10 is provided with an outer thread 18, which provides a tension-introducing structure for introducing rearwardly-directed tension into the anchor bolt 10. A nut 8 can be threadedly engaged on the outer thread 18.

[0040] The expansion sleeve 30 can be provided with a plurality of slits (not shown), which originate from the front end of the expansion sleeve 30 and extend towards the rear end of the expansion sleeve 30.

[0041] When the anchor is installed, the anchor bolt 10 and the wedge body 12 are pushed, front end first and, into a hole in a substrate 5. In this process, the anchor bolt 10 and the wedge body 12 are moved parallel to the longitudinal axis 99 in the forwards direction, i.e., in the direction opposite to the rearwards direction 101. The shoulder 17 engages the expansion sleeve 30, so that the expansion sleeve 30 follows the movement of the anchor bolt 10. Subsequently, the wedge body 12 is drawn into the front-end region of the expansion sleeve 30, by moving the wedge body 12 relative to the expansion sleeve 30 in the rearwards direction 101. In the present embodiment, this is achieved by pulling the anchor bolt 10 together with the wedge body 12 rearwardly, in particular by tightening the nut 8 provided on the outer thread 18 of the anchor bolt 10. When the wedge body 12 is drawn into the front-end region of the expansion sleeve 30, the expansion sleeve 30 is radially widened by wedge body 12 and is pressed against the wall of the hole. The expansion anchor is fixed in substrate 5 as a result of this mechanism. The installed state of the expansion anchor, in which it is fixed in substrate 5, is shown in FIG. 1. A mounting part 6 may be fixed to the substrate 5 with the aid of nut 8.

[0042] In an area of contact with the expansion sleeve 30, which area of contact is formed on the converging zone 23 of the wedge body 12, the wedge body 12 is covered by a double coating comprising a base layer 61 and a top layer 62 that covers the base layer 61. This double coating is shown in FIG. 2. The base layer 61 is located sandwiched between the top layer 62 and the wedge body 12 that carries the two layers 61, 62, in particular in an adhesively bound manner. The base layer 61 is a hot dip galvanized zinc layer, a ZnFe layer or a ZnNi layer, and the top layer 62 is zinc flake and/or aluminum flake layer. The wedge body 12, and preferably also the anchor bolt 10, consists of carbon steel. The expansion sleeve 30 can for example consist of stainless steel, or of coated carbon steel.

[0043] In the exemplary embodiment of FIGS. 1 and 2, the double coating consisting of layers 61 and 62 is shown to be located on the wedge body 12. However, the double coating having layers 61 and 62 may additionally extend into neck area 11, or beyond. In particular, the double coating can cover all of the surface of the wedge body 12 and of the anchor bolt 10. Such an embodiment is shown in FIG. 3, in which the double coating is indicated, in a strongly magnified manner, by dashed lines. The expansion sleeve is omitted in FIG. 3 for the sake of clarity, in order to highlight the double layer. An expansion sleeve to be used in the embodiment of FIG. 3 can for example be chosen in analogy to that of FIGS. 1 and 2.

[0044] The expansion anchors in the exemplary embodiments of FIGS. 1 to 3 are of the “wedge anchor” type. Another exemplary embodiment, in which the expansion anchor is of the “sleeve anchor” type, is shown in FIGS. 4 and 5. In the embodiments of FIGS. 1 to 3, the respective wedge bodies 12 are axially fixedly fastened to the anchor bolt 10 and in particular integral with the anchor bolt 10. In contrast, in the exemplary embodiment of FIGS. 4 and 5, the wedge body 12 can be axially displaced relatively to the anchor bolt 10. In particular, the wedge body 12 with the converging zone 23 has an internally threaded hole, and the anchor bolt 10 has a corresponding outer thread. The corresponding threads form a transmission mechanism, which can translate rotation of the anchor bolt 10 relative to the wedge body 12 into axial displacement of the wedge body 12 relative to the anchor bolt 10. In addition, in the expansion anchor of FIGS. 4 and 5, the expansion sleeve 30, which may also consist of several tubular pieces, extends to the mouth of the hole, and a widened head 88 is rotatably fixed to the anchor bolt 10 at the rear end area of the anchor bolt 10.

[0045] For installing the expansion anchor of FIGS. 4 and 5, the anchor bolt 10 is set in rotation around longitudinal axis 99, preferably via the head 88. The corresponding threads convert this rotational movement of the anchor bolt 10 into an axial movement of the wedge body 12 relative to the anchor bolt 10 and thus relative to the expansion sleeve 30, resulting in the wedge body 12 being drawn into the expansion sleeve 30.

[0046] The expansion anchor of FIGS. 4 and 5 has once again a double coating comprising a base layer 61 and a top layer 62, which double coating covers the wedge body 12, at least in an area of contact with the expansion sleeve 30, which area of contact is located on the converging zone 23 of the wedge body 12. The base layer 61 is a hot dip galvanized zinc layer, a ZnFe layer or a ZnNi layer, and the top layer 62 is zinc flake and/or aluminum flake layer. The wedge body 12, and preferably also the anchor bolt 10, consists of carbon steel. The expansion sleeve 30 can for example consist of stainless steel, or of coated carbon steel.