Expanding wall anchor and use for fixing a component to a support material

Abstract

Expanding wall anchor, comprising (i) a threaded longitudinal body formed as a single piece with an expansion cone at one of its ends, this cone being connected to the rest of the body by a cylindrical portion of diameter d1 smaller than the nominal diameter D of the body, and (ii) an expanding sleeve of thickness e mounted around the said cylindrical portion of the body and through which the expansion cone is intended to be moved in order to deform the sleeve and anchor the wall anchor in a hole in a support material, characterized in that the ratio d1/D is greater than or equal to 60% and the ratio e/d1 is greater than or equal to 22%.

Claims

1. An expanding wall anchor, comprising: i) a longitudinal body formed as a single piece and including an expansion cone, a cylindrical portion, and a threaded portion, wherein the expansion cone forms a first end of the longitudinal body, the threaded portion forms a second opposing end of the longitudinal body, and the expansion cone is connected to the threaded body via the cylindrical portion, and ii) an expanding sleeve of thickness (e) mounted around the cylindrical portion of the body and through which the expansion cone is configured to move to deform the expanding sleeve and to anchor the expanding wall anchor in a hole in a support material, wherein the cylindrical portion has a diameter (d1), the longitudinal body has a nominal diameter (D), and the diameter of the cylindrical portion (d1) is smaller than the nominal diameter of the longitudinal body (D), the expanding sleeve has a maximum outside diameter (d2) that is substantially equal to the nominal diameter of the longitudinal body (D), a first ratio (d1/D) of the diameter of the cylindrical portion (d1) to the nominal diameter of the longitudinal body (D) is greater than or equal to 60%, and a second ratio (e/d1) of the thickness of the expanding sleeve (e) to the diameter of the cylindrical portion (d1) is greater than or equal to 22%.

2. The expanding wall anchor of claim 1, wherein the second ratio (e/d1) of the thickness of the expanding sleeve (e) to the diameter of the cylindrical portion (d1) is less than 35%.

3. The expanding wall anchor of claim 1, wherein the expansion cone has an angle (a) greater than or equal to 25 degrees.

4. The expanding wall anchor of claim 1, wherein the expansion cone has an angle (a) greater than or equal to 26 degrees.

5. The expanding wall anchor of claim 1, wherein the expansion cone has an angle (a) less than or equal to 35 degrees.

6. The expanding wall anchor of claim 1, wherein the expansion cone has an angle (a) less than or equal to 30 degrees.

7. The expanding wall anchor of claim 1, wherein the nominal diameter of the longitudinal body (D) is between 6 mm and 30 mm.

8. The expanding wall anchor of claim 1, wherein the diameter of the cylindrical portion (d1) is between 3 mm and 15 mm.

9. The expanding wall anchor of claim 1, wherein the thickness of the expanding sleeve (e) is between 0.7 mm and 3.5 mm.

10. The expanding wall anchor of claim 1, wherein the expanding sleeve has a length representing less than 25% of a length of the longitudinal body.

11. The expanding wall anchor of claim 10, wherein the expanding sleeve has a length representing less than 20% of a length of the longitudinal body.

12. The expanding wall anchor of claim 1, wherein the expansion cone has a maximum diameter (d3) substantially equal to the nominal diameter of the longitudinal body (D).

13. The expanding wall anchor of claim 1, wherein the cylindrical portion of diameter (d1) is connected by a cylindrical portion of nominal diameter (D) to a threaded part of the longitudinal body.

14. The expanding wall anchor of claim 1, wherein the expanding wall anchor is configured for fixing an object to the support material.

15. The expanding wall anchor of claim 1, wherein the expanding wall anchor is configured for fixing an object to the support material, and wherein the support material is liable to be subjected to seismic loadings.

16. The expanding wall anchor of claim 1, wherein the expanding wall anchor is configured to hold fast under seismic loading in cracked concrete.

17. The expanding wall anchor of claim 1, wherein: the first ratio (d1/D) of the diameter of the cylindrical portion (d1) to the nominal diameter of the longitudinal body (D) is greater than or equal to 60%, the second ratio (e/d1) of the thickness of the expanding sleeve (e) to the diameter of the cylindrical portion (d1) is greater than or equal to 22%, the second ratio (e/d1) of the thickness of the expanding sleeve (e) to the diameter of the cylindrical portion (d1) is less than 35%, the expansion cone has an angle (a) that is greater than or equal to 27 degrees, and the angle of the expansion cone (a) is less than or equal to 30 degrees, the expanding sleeve has an outside diameter (d2) substantially equal to the nominal diameter of the longitudinal body (D), the nominal diameter of the longitudinal body (D) is between 8 mm and 16 mm, the diameter of the cylindrical portion (d1) is between 3 mm and 15 mm, the thickness of the expanding sleeve (e) is between 0.7 mm and 3.5 mm, and the expanding sleeve has a length representing less than 20% of a length of the longitudinal body.

18. An expanding wall anchor, comprising: a longitudinal body which is a single piece and comprises: an expansion cone forming a first end of the longitudinal body, a first cylindrical portion having a first end and an opposing second end, wherein the first end of the first cylindrical portion is connected to an end of the expansion cone, a second cylindrical portion having a first end and an opposing second end, wherein the first end of the second cylindrical portion is connected to the second end of the first cylindrical portion, and a threaded portion forming a second end of the longitudinal body, wherein an end of the threaded portion is connected to the second end of the second cylindrical portion; and an expanding sleeve of thickness (e) which is mounted around the first cylindrical portion of the longitudinal body and into which the expansion cone is configured to move to deform the expanding sleeve and to anchor the expanding wall anchor in a hole in a support material, wherein: the expansion cone, the first cylindrical portion, the second cylindrical portion, and the threaded portion are formed from a single piece, the first cylindrical portion has a diameter (d1), the second cylindrical portion has a diameter (D), and the diameter of the first cylindrical portion (d1) is less than the diameter of the second cylindrical portion (D), the expanding sleeve has a maximum outside diameter (d2) that is substantially equal to the diameter of the second cylindrical portion (D), a first ratio (d1/D) of the diameter of the first cylindrical portion (d1) to the diameter of the second cylindrical portion (D) is greater than or equal to 60%, a second ratio (e/d1) of the thickness of the expanding sleeve (e) to the diameter of the first cylindrical portion (d1) is greater than or equal to 22%, and the expansion cone has an angle (a) greater than or equal to 27 degrees.

19. An expanding wall anchor, comprising: a longitudinal body which is a single piece and comprises: an expansion cone forming a first end of the longitudinal body, a first cylindrical portion having a first end and an opposing second end, wherein the first end of the first cylindrical portion is connected to an end of the expansion cone, a second cylindrical portion having a first end and an opposing second end, wherein the first end of the second cylindrical portion is connected to the second end of the first cylindrical portion, and a threaded portion forming a second end of the longitudinal body, wherein an end of the threaded portion is connected to the second end of the second cylindrical portion; and an expanding sleeve of thickness (e) which is mounted around the first cylindrical portion of the longitudinal body and into which the expansion cone is configured to move to deform the expanding sleeve and to anchor the expanding wall anchor in a hole in a support material, wherein: the expansion cone, the first cylindrical portion, the second cylindrical portion, and the threaded portion are formed from a single piece, the first cylindrical portion has a diameter (d1), the second cylindrical portion has a diameter (D), and the diameter of the first cylindrical portion (d1) is less than the diameter of the second cylindrical portion (D), the expanding sleeve has a maximum outside diameter (d2) that is substantially equal to the diameter of the second cylindrical portion (D), a first ratio (d1/D) of the diameter of the first cylindrical portion (d1) to the diameter of the second cylindrical portion (D) is greater than or equal to 60%, a second ratio (e/d1) of the thickness of the expanding sleeve (e) to the diameter of the first cylindrical portion (d1) is greater than or equal to 22%, and the threaded portion has a length greater than a combined length of the cone, the first cylindrical portion, and the second cylindrical portion.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention will be better understood and further details, features and advantages of the present invention will become more clearly apparent from reading the following description, given by way of nonlimiting example with reference to the attached drawings, in which:

(2) FIG. 1 is a schematic view of an expanding wall anchor according to the invention; and

(3) FIG. 2 is another schematic view, in this instance an exploded view, of the wall anchor of FIG. 1; and

(4) FIG. 3 is a schematic view in cross section of a support material in a hole of which an expanding wall anchor according to the invention is anchored.

DETAILED DESCRIPTION

(5) The wall anchor 10 of FIG. 1, intended for fixing a component to a support material, comprises a longitudinal body 12 of axis X and an expanding sleeve 14 mounted coaxially around the body.

(6) The body 12 essentially comprises an expansion cone 16 of angle and of maximum diameter d2 (FIG. 2), a cylindrical portion 18 of diameter d1, a cylindrical portion 20 of diameter D, and a threaded part 22 which is able to accept a washer 24 and a nut 26.

(7) The expansion cone 16 is situated at one end of the body 12 and is connected by the portion 18 of diameter d1 to the portion 20 of diameter D. d1 is less than D which is the nominal diameter of the body 12 and which is substantially equal to the receiving or anchor hole bored in the support material. Thus, the portion 18 defines an annular groove between the cone 16 and the rest of the body 12.

(8) The portion 20 extends between the portion 18 and the threaded part 22 which generally has a length greater than the combined lengths of the cone 16 and of the portions 18, 20, along the axis X.

(9) The body 12, comprising the cone 16, the portions 18, 20 and the threaded part 22, is formed as a single piece, generally of a hard and strong metal alloy (such as a steel). In theory, it is of solid cross section over its entire length.

(10) The region of connection between the cylindrical portions 18, 20 may comprise an external radial shoulder 28 (FIG. 2) which is notably intended to act as an axial end stop for the sleeve 14 when the wall anchor 10 is being inserted into the support material. If this shoulder 28 is formed of an annular collar 30, this collar may be considered to define the nominal diameter D of the body 12.

(11) The expanding sleeve 14 is mounted around the portion 18, i.e. in the aforementioned groove of the body 12. The sleeve 14 has a thickness e and an outside diameter d2.

(12) The sleeve 14 is preferably mounted with clearance, particularly radial clearance, on this portion so that it can move along it. The radial clearance on the radius is preferably comprised between 0.05 and 0.3 mm.

(13) This sleeve 14 is obtained in the usual way from a flat sheet material blank (generally sheet metal blank), which is cut, bent, struck and/or rolled so that once mounted on the portion 18 of the body 12 it has the desired skirt shape with a longitudinal slit. The sleeve 14 may comprise projecting external lugs that anchor into the support material, the radially external ends of these lugs potentially being on a circumference centred on the axis X and the diameter of which is slightly greater than the nominal diameter D of the body.

(14) The sleeve 14 is mounted around the portion 18 of the body by crimping such that the longitudinal edges of the sleeve face and are close to one another, with a relatively narrow slit separating them. Once crimped, the sleeve 14 is preferably able to move, within the extent of the functional clearance, axially and rotationally with respect to the body 12.

(15) This expanding sleeve 14 is intended to have the expansion cone 16 of the body 12 pass partially through it so that once it has deformed it anchors in the wall of a receiving or anchor hole in a support material.

(16) As FIGS. 1 and 2 show, the sleeve 14 may at its end situated at the same end as the cone 16 have an entry chamfer which gives this end a certain conicity, so that once it has been mounted around the portion 18 of the body, the sleeve 14 has a frustoconical shape that more or less complements that of the expansion cone 16 of the body.

(17) According to the invention, the wall anchor 10 is dimensioned such that the ratio d1/D is greater than or equal to 60% and that the ratio e/d1 is greater than or equal to 22%. Moreover, the aforementioned angle of the cone 16 of the wall anchor is preferably comprised between 27 and 30, and preferably measures approximately 27.

(18) As far as the d1/D ratio is concerned, the minimum value of 60% amounts to expressing the depth of the annular groove defined by the portion 18 of the body. In order not to weaken the body, this groove has not to be too deep, as too deep a groove results in a small-section portion 16 which therefore has low mechanical strength. The following table sets out the minimum value of d1 for various values of the nominal diameter of the body of the wall anchor.

(19) TABLE-US-00001 Nominal diameter D Minimum value of d1 (in mm) (in mm - for a d1/D ratio 0.6) 6 3.6 8 4.8 10 6 12 7.2 16 9.6

(20) The ratio e/d1 has a minimum value for guaranteeing the wall anchor good mechanical properties and, in particular, good ability to hold fast under seismic loadings.

(21) The following table gives, by way of example, minimum values for the thickness e of the sleeve, which have been deduced from the d1 values from the previous table.

(22) TABLE-US-00002 Minimum value of e Nominal diameter D Minimum value of d1 (in mm - for an e/d1 (in mm) (in mm) ratio 0.22) 6 3.6 0.792 8 4.8 1.056 10 6 1.32 12 7.2 1.584 16 9.6 2.112

(23) Of course, the values of d1 and of e of the wall anchor according to the invention are dependent on the nominal diameter D of the wall anchor and on the aforementioned ratios d1/D and e/d1. The next table gives other examples of values of the thickness e for the same ratio d1/D (0.6) and for a e/d1 ratio greater than or equal to 25%.

(24) TABLE-US-00003 Minimum value of e Nominal diameter Minimum value of d1 (in mm - for an e/d1 (in mm) (in mm) ratio 0.25) 6 3.6 0.9 8 4.8 1.2 10 6 1.5 12 7.2 1.8 16 9.6 2.4

(25) Fitting the expanding wall anchor according to the invention into a support material does not present any difficulties and can be done usually in the following way, with reference to FIG. 3.

(26) Beforehand, a blind anchor or receiving hole T of diameter D is bored in the support material MS which is generally a hard material (concrete).

(27) The depth of the hole is at least equal to the combined lengths of the cone 16, of the portion 18 and of at least part of the portion 20 (or of the collar 30).

(28) The wall anchor 10 is introduced, expansion cone 16 end first, into the hole T using a tool, such as a hammer, acting on the transverse face 32 of the body 12, at the opposite end from the cone 16. As the cone 16 is driven into the hole T the sleeve 14, driven axially by the shoulder 28 or the collar 30 of the body, is introduced at the same time.

(29) The wall anchor 10 is therefore introduced into the hole T, with the expansion cone 16 ready to deform the sleeve 14 to anchor it completely in the wall P of the hole.

(30) To achieve that, axial tension is applied in the direction of the arrow F to the body, towards the outside end of the hole T, which tension is obtained by the clamping nut 26, depicted in chain line in FIG. 3, screwed onto the threaded part 22 of the body and used to attach a component PI, likewise depicted in chain line and mounted around the body 12 so that it sits against the face FE of the support material MS.

(31) As the nut 26 is tightened, the expansion cone 16 is pulled and enters the sleeve 14, which sleeve, because of its frustoconical shape which is the reverse of that of the cone, experiences an expansion right from the start of the tensile force applied by the retreating cone 16 and engages in the wall P of the hole. Thus, the sleeve 14 is immediately immobilized axially in position, preventing it from riding up in the hole.

(32) As the expansion cone 16 gradually penetrates the sleeve 14, as a result of the tightening of the nut 26, to reach the final position illustrated in FIG. 3, for which the cone is appreciably engaged in the sleeve, the sleeve 14 undergoes an expansion such that it is forced to penetrate (arrows E) the wall P of the hole T so that the sleeve 14 is perfectly anchored in the support material MS.

(33) The wall anchor 10 is then operational, fully immobilized by the tightening of the nut 26 that attaches the component PI to the support material MS.

EXAMPLE

(34) The description that follows contains a comparative example to illustrate the foregoing.

(35) We have compared a product according to the invention (product A) that meets all of the requirements stipulated for cracked concrete and seismic loadings against a product of the prior art that meets only the requirements stipulated for cracked concrete without seismic loadings (product B) and against a third product designed exclusively for non-cracked concrete (product C). The three wall anchors compared have the same nominal diameter, in this instance 12 mm (M12), and were set at identical anchoring depths into concretes of identical strengths. The various components of these wall anchors are made of comparable steels commonly used by those skilled in the art. The only appreciable differences are their ratio e/d1 and their angle as defined above. The reference wall anchor is the wall anchor according to the invention (product A) which works under all the conditions and for which we consider the ultimate strength (RLU) (or design resistance) to be 100%.

(36) The table below summarizes the results and parameters of our example.

(37) TABLE-US-00004 Does it work in Does it work in cracked concrete with Product e/d1 RLU concrete seismic loading A 25.6% 27 100% YES YES B 17.4% 20 100% NO NO B 17.4% 20 75% YES NO C 17.4% 16 100% NO NO C 17.4% 16 56% YES NO

(38) Product A has an e/d1 ratio greater than 22%, in this instance of 25.6%, an angle equal to 27 and works in all conditions. This is our reference.

(39) Product B designed for cracked concrete but not for seismic loadings has an e/d1 ratio of less than 22%, in this instance of 17.4%, and an angle less than 27, in this instance of 20. Its performance in cracked concrete is only 75% of the RLU of product A. If product B is loaded to achieve 100% of the RLU of product A, it no longer works in cracked concrete. This product B is not designed for seismic loading.

(40) Product C designed solely for non-cracked concrete has an e/d1 ratio of less than 22%, in this instance of 17.4%, and an angle less than 27, in this instance of 16. We reduced its RLU progressively in an attempt to make it work in cracked concrete but under lighter load. At the end of this exercise, the RLU of product C that allowed it to function in cracked concrete was only 56% of the RLU of product A.

(41) This example clearly demonstrates the benefit of the invention and the significance of the claimed parameters in the performance of products in relation to the prior art.