U.S. patent number 10,385,898 [Application Number 15/036,088] was granted by the patent office on 2019-08-20 for expanding wall anchor and use for fixing a component to a support material.
This patent grant is currently assigned to Illinois Tool Works Inc.. The grantee listed for this patent is ILLINOIS TOOL WORKS INC.. Invention is credited to Fabrice Pourtier.
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United States Patent |
10,385,898 |
Pourtier |
August 20, 2019 |
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%.
Inventors: |
Pourtier; Fabrice
(Portes-les-Valence, FR) |
Applicant: |
Name |
City |
State |
Country |
Type |
ILLINOIS TOOL WORKS INC. |
Glenview |
IL |
US |
|
|
Assignee: |
Illinois Tool Works Inc.
(Glenview, IL)
|
Family
ID: |
49917117 |
Appl.
No.: |
15/036,088 |
Filed: |
August 21, 2014 |
PCT
Filed: |
August 21, 2014 |
PCT No.: |
PCT/US2014/052199 |
371(c)(1),(2),(4) Date: |
May 12, 2016 |
PCT
Pub. No.: |
WO2015/073085 |
PCT
Pub. Date: |
May 21, 2015 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20160273570 A1 |
Sep 22, 2016 |
|
Foreign Application Priority Data
|
|
|
|
|
Nov 13, 2013 [FR] |
|
|
13 61072 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16B
13/065 (20130101) |
Current International
Class: |
F16B
13/06 (20060101) |
Field of
Search: |
;411/60.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
ISR and WO for PCT/US2014/052199 dated Oct. 22, 2014. cited by
applicant.
|
Primary Examiner: Estremsky; Gary W
Attorney, Agent or Firm: Neal, Gerber & Eisenberg
LLP
Claims
The invention claimed is:
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
RELATED APPLICATIONS
The present application is a National Phase of International
Application Number PCT/US2014/052199, filed Aug. 21, 2014, and
claims priority to French Application Number 1361072, filed Nov.
13, 2013.
TECHNICAL FIELD
The invention relates to an expanding wall anchor and its use for
fixing a component to a support material, particularly a support
material liable to be subjected to seismic loadings.
PRIOR ART
Typically, an expanding wall anchor comprises 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 smaller than the nominal
diameter of the body, and ii) an expanding sleeve 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.
Documents US-A1-2010/0104393 and WO-A1-2012/120488 describe wall
anchors of this type.
A wall anchor of this type is generally used in a concrete support
after a receiving hole has been drilled therein with the nominal
diameter of the body. The end part of the wall anchor comprising
the expansion cone and bearing the expanding sleeve is forcibly
engaged in this hole, for example by striking the wall anchor with
a hammer. The component to be fixed is attached to the support
material in such a way that the threaded part of the wall anchor
passes through the component to be fixed, this threaded part
accepting a nut that clamps the component against the support
material. This clamping causes the body to undergo an axial
translational movement with respect to the sleeve of the wall
anchor, towards the outside end of the hole. The cone of the body
therefore collaborates with the sleeve and forces it to expand,
thus anchoring the sleeve in the support material and retaining the
wall anchor with respect to the support material.
After the sleeve has been expanded, the tensile strength of this
type of wall anchor is generally dependent on the cross section of
the cylindrical portion of the body housing the sleeve, which is
the smallest-diameter portion of the body of the wall anchor (as
long as the sleeve holds fast in the support material and as long
as the latter is able to withstand the stresses generated by the
fixing).
However, regulations in this area are now evolving towards products
that have been type tested for seismic loadings. This results in
increasingly strict product testing conditions. In particular, the
products have to undergo dynamic testing in cracked concrete the
crack widths of which increase with each new seismic condition. The
known products which were able to meet the earlier type testing
certification conditions generally experience a drop in their
performance, or even sometimes are no longer able to function at
all under seismic loadings.
These changes to the type testing certification conditions,
particularly the increase in the width of the cracks in the support
material accepting this type of wall anchor during the
certification testing, mean that the sleeve has greater difficulty
holding fast in the support material, or suitably holding the body
of the wall anchor when the latter experiences seismic
loadings.
The present invention proposes a simple, effective and economical
solution to this problem.
SUMMARY OF THE INVENTION
The invention thus proposes an 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%.
In the present application, d1 is the (outside) diameter of the
cylindrical portion of the body of the wall anchor, around which
the sleeve is mounted. D is the nominal diameter of the body of the
wall anchor, namely the maximum (outside) diameter of the body. e
is the thickness of the sleeve and more specifically the thickness
of material of this sleeve (which is equal to the thickness of the
metal sheet used to produce the sleeve when the sleeve is made from
such sheet metal). It is conceivable for the thickness of the
sleeve not to be perfectly constant, particularly when that end of
the sleeve that is situated at the expansion cone end is thinner.
It is also conceivable for this thickness e to vary because of the
presence of anchoring lugs on the external surface of the sleeve or
of local slits in the sleeve. The thickness e of the sleeve can
therefore be considered to be measured here some distance from its
ends and away from any zones of the sleeve that have lugs or slits.
The sleeve may have an outside diameter d2 substantially equal to
the nominal diameter D. As indicated in the foregoing, this
diameter d2 is preferably measured some distance from the ends of
the sleeve and away from such zones as have lugs or slits.
The applicant company has sought to optimize dimensional parameters
of the wall anchor and has discovered that a ratio e/d1 (the ratio
of the thickness of the sleeve to the diameter of the cylindrical
portion of the body on which the sleeve is mounted) greater than or
equal to 22% unexpectedly makes it possible to achieve very good
results in terms of the mechanical and vibratory performance of the
wall anchor under seismic loadings, even when anchored in a crack
that is relatively wide. The ratio d1/D is greater than or equal to
60%, i.e. the diameter d1 is greater than 0.6 D, making it possible
to give the wall anchor sufficient mechanical strength because, as
explained in the foregoing, the tensile strength of the wall anchor
is generally dependent on the cross section of this
smallest-section portion of the body (it being possible for D to be
comprised between 6 and 30 mm and, for example, measuring 8, 10, 12
or 16 mm). From a given value of d1, it is therefore possible to
deduce the value of the sleeve thickness e that will give the wall
anchor the desired properties. For a wall anchor of given nominal
diameter D, this wall anchor will have a sleeve the thickness e of
which will be greater than the thicknesses of the sleeves of the
wall anchors of the prior art (in which the e/d1 ratios are
markedly below 22%). Increasing the thickness e of the sleeve
allows it to be made less sensitive to the increase in the width of
the cracks and allows it to hold more fast under seismic loadings.
In the aforementioned instance in which the sleeve is made from
sheet metal, that amounts to using a thicker metal sheet from which
to make the sleeve of the wall anchor according to the
invention.
The ratio e/d1 may be greater than or equal to 23, 24 or 25%.
This ratio e/d1 is preferably less than 35%, or even 34, 33, 32, 31
or 30%. Specifically, in order to guarantee a sufficient resistive
cross section with the steels commonly used by those skilled in the
art to make the body of this type of wall anchor, the ratio e/d1
preferably has not to be too high, particularly in the case of
small-diameter wall anchors which are more sensitive to body
breakages.
The diameter d1 may be comprised between 3 and 15 mm, preferably
between 4 and 13 mm, and more preferably between 5 and 12 mm. The
thickness e may be comprised between 0.7 and 3.5 mm, preferably
between 0.9 and 3 mm, and more preferably between 1 and 2.5 mm.
The expansion cone of the wall anchor may have an angle .alpha.
greater than or equal to 25, 26, and preferably 27.degree.. This
angle .alpha. may be less than or equal to 35.degree. and
preferably less than or equal to 30.degree..
The sleeve may have an end, situated at the expansion cone end,
that has a conicity obtained for example by an entry chamfer.
The applicant company has sought to improve the performance of its
wall anchor still further in cracked concrete under seismic
loading. It has thus had the idea of significantly increasing the
angle .alpha. of the expansion cone by comparison with the values
commonly employed in the current state of the art. This angle
.alpha. is actually generally less than or equal to 20.degree. for
wall anchors intended for non-cracked concrete, and of the order of
20 to 22.degree. for those intended to work in cracked
concrete.
A large angle .alpha. generates significant stress at the contact
between the sleeve and the expansion cone of the body. This stress,
if excessively high, has the effect of causing the sleeve to seize
on the body, destroying the contact surface, which is detrimental
to the overall operation of the wall anchor under such conditions.
Sometimes the person skilled in the art uses an antifriction
coating at this point of contact, in order to push back the limits
of seizure described above. However, this coating has the
disadvantage of reducing the holding performance of the wall anchor
under the conditions described above. The applicant company,
seeking to obtain superior performance despite the new seismic
conditions, has raised the value of this angle .alpha. to at least
27.degree., which goes against the technical preconceptions in this
art. Astonishingly, recourse to these high angle .alpha. values has
made it possible to improve the operation and hold fast ability of
the wall anchors. Increasing the value of the angle .alpha. without
seizure has in fact between made easier by the increase in the
thickness e of the sleeve which allows this sleeve to withstand
more severe operating conditions and makes it possible to push back
the permissible limits at the sleeve/expansion cone contact region.
The combination of these parameters has allowed the applicant
company to produce wall anchors that function perfectly under
seismic loading in cracked concrete while at the same time
improving their ultimate strength, and as a result, their maximum
safe working load.
The sleeve may have a length representing less than 25%, and for
example less than 20%, of that of the body.
The cone may have a maximum diameter d3 substantially equal to the
nominal diameter D.
The cylindrical portion of diameter d1 may be connected by a
cylindrical portion of nominal diameter D to a threaded part of the
body.
The present invention also relates to a use of a wall anchor as
described hereinabove for fixing an object to a support material,
particularly a support material liable to be subjected to seismic
loadings.
BRIEF DESCRIPTION OF THE FIGURES
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:
FIG. 1 is a schematic view of an expanding wall anchor according to
the invention; and
FIG. 2 is another schematic view, in this instance an exploded
view, of the wall anchor of FIG. 1; and
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
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.
The body 12 essentially comprises an expansion cone 16 of angle
.alpha. 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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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 .alpha. of the cone 16 of the wall anchor is
preferably comprised between 27 and 30.degree., and preferably
measures approximately 27.degree..
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.
TABLE-US-00001 Nominal diameter D Minimum value of d1 (in mm) (in
mm - for a d1/D ratio .gtoreq. 0.6) 6 3.6 8 4.8 10 6 12 7.2 16
9.6
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.
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.
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 .gtoreq. 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
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 (.gtoreq.0.6) and for a e/d1 ratio greater than
or equal to 25%.
TABLE-US-00003 Minimum value of e Nominal diameter Minimum value of
d1 (in mm - for an e/d1 (in mm) (in mm) ratio .gtoreq. 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
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.
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).
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).
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.
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.
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.
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.
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.
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
The description that follows contains a comparative example to
illustrate the foregoing.
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 .alpha. 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%.
The table below summarizes the results and parameters of our
example.
TABLE-US-00004 Does it work in Does it work in cracked concrete
with Product e/d1 .alpha. 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
Product A has an e/d1 ratio greater than 22%, in this instance of
25.6%, an angle .alpha. equal to 27.degree. and works in all
conditions. This is our reference.
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 .alpha. less than 27.degree., in this instance
of 20.degree.. 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.
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
.alpha. less than 27.degree., in this instance of 16.degree.. 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.
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.
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