U.S. patent application number 14/004655 was filed with the patent office on 2014-03-13 for expansion anchor.
This patent application is currently assigned to HILTI Aktiengesellschaft. The applicant listed for this patent is Matthias Wissling. Invention is credited to Matthias Wissling.
Application Number | 20140072384 14/004655 |
Document ID | / |
Family ID | 45592413 |
Filed Date | 2014-03-13 |
United States Patent
Application |
20140072384 |
Kind Code |
A1 |
Wissling; Matthias |
March 13, 2014 |
EXPANSION ANCHOR
Abstract
An expansion anchor is disclosed. The expansion anchor includes
an anchor bolt with a longitudinal axis and an expansion body on a
first terminal section of the anchor bolt, an actuator on a second
terminal section of the anchor bolt, and an expansion sleeve which
surrounds the anchor bolt. The expansion body, on the radial
outside, is at different distances from the longitudinal axis with
reference to at least one identical point on the longitudinal axis
in a transfer zone.
Inventors: |
Wissling; Matthias; (St.
Gallen, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Wissling; Matthias |
St. Gallen |
|
CH |
|
|
Assignee: |
HILTI Aktiengesellschaft
Liechtenstein
DE
|
Family ID: |
45592413 |
Appl. No.: |
14/004655 |
Filed: |
February 16, 2012 |
PCT Filed: |
February 16, 2012 |
PCT NO: |
PCT/EP2012/052669 |
371 Date: |
November 21, 2013 |
Current U.S.
Class: |
411/44 |
Current CPC
Class: |
E04B 1/40 20130101; F16B
13/066 20130101; F16B 13/063 20130101; F16B 13/065 20130101 |
Class at
Publication: |
411/44 |
International
Class: |
F16B 13/06 20060101
F16B013/06 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 23, 2011 |
DE |
10 2011 005 999.7 |
Claims
1-11. (canceled)
12. An expansion anchor, comprising: an anchor bolt with a
longitudinal axis and an expansion body on a first terminal section
of the anchor bolt; an actuator disposed on a second terminal
section of the anchor bolt; and an expansion sleeve disposed around
the anchor bolt; wherein the expansion body, on a radial outside in
a transfer zone, has a plurality of first points that are located
at a maximum distance from the longitudinal axis and a plurality of
seconds point that are located at a minimum distance from the
longitudinal axis; and wherein the expansion sleeve is radially
expandable by the plurality of first points.
13. The expansion anchor according to claim 12, wherein the
transfer zone is corrugated or serrated and wherein the maximum
distance and the minimum distance differ by at least 1%.
14. The expansion anchor according to claim 12, wherein the
expansion body outside of the transfer zone has a conical
geometry.
15. The expansion anchor according to claim 12, wherein the
transfer zone has a shape essentially of a cylinder, wherein the
cylinder shape has a longitudinal axis, and wherein the
longitudinal axis of the cylinder shape is coaxial with the
longitudinal axis of the anchor bolt.
16. The expansion anchor according to claim 12, wherein the
transfer zone has an essentially conical shape and wherein an apex
angle of the transfer zone is smaller than an apex angle of the
expansion body outside of the transfer zone.
17. The expansion anchor according to claim 12, wherein the
plurality of first points are connected by a virtual circumscribed
circle wherein a center of the circumscribed circle corresponds to
the longitudinal axis, and wherein the plurality of second points
are connected by a virtual inscribed circle wherein a center of the
inscribed circle corresponds to the longitudinal axis.
18. The expansion anchor according to claim 17, wherein a radius of
the circumscribed circle differs by at least 1% from a radius of
the inscribed circle.
19. The expansion anchor according to claim 17, wherein the
expansion body outside of the transfer zone is conical and wherein
in the transfer zone the inscribed circle or the circumscribed
circle has an essentially constant radius.
20. The expansion anchor according to claim 17, wherein a radius of
the circumscribed circle has a deviation of less than 10% and
wherein a radius of the inscribed circle has a deviation of less
than 10%.
21. The expansion anchor according to claim 12, wherein the
actuator is comprised of a thread on the anchor bolt and a shim and
a nut disposed on the thread.
22. The expansion anchor according to claim 12, wherein the anchor
bolt and/or the expansion body and/or the actuator are made at
least partly of a metal.
23. The expansion anchor according to claim 22, wherein the metal
is steel.
Description
[0001] This application claims the priority of International
Application No. PCT/EP2012/052669, filed Feb. 16, 2012, and German
Patent Document No. 10 2011 005 999.7, filed Mar. 23, 2011, the
disclosures of which are expressly incorporated by reference
herein.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] This invention relates to an expansion anchor.
[0003] Expansion anchors with an anchor bolt, an expansion body,
action means and an expansion sleeve surrounding the anchor bolt
are used to fasten workpieces to a structural component. For this
purpose, a boring is worked into the structural component which can
be, for example, a concrete wall or a concrete ceiling, and then
the anchor bolt is inserted into the boring. With the action means,
the conical expansion body on the anchor bolt is moved so that the
expansion body thereby presses the expansion sleeve radially
outward resulting in an anchoring of the expansion bolt as a result
of radial forces between the expansion sleeve or the expansion body
and the structural component, such as the concrete that surrounds
the boring. Workpieces or other items can thereby be fastened to
the expansion anchor.
[0004] Between the expansion anchor and the wall of the borehole, a
friction force between the wall of the borehole in the structural
component and the expansion sleeve effects the anchoring of the
expansion anchor. The conical expansion bodies are rotationally
symmetrical to a longitudinal axis of the anchor bolt or of the
expansion body.
[0005] German Patent Document No. DE 41 16 149 A1 describes an
expansion anchor with anchor bolts, the cylindrical shank of which
has an expanded portion in a terminal portion in the direction of
installation, and on the end farther from this expanded portion has
action means to bear the load, whereby the anchor bolt is
surrounded at least along a portion of its shank by an expansion
sleeve that can be displaced relative to the anchor bolt and has at
least one longitudinal slot that is open toward the
installation-side end and is provided with radial projections on
its external contour.
[0006] The object of this invention is therefore to make available
an expansion anchor in which a solid connection between the anchor
sleeve and the concrete can be achieved with low manufacturing
costs of the expansion anchor.
[0007] This object is accomplished with an expansion anchor that
comprises an anchor bolt with an expansion body on a first terminal
section of the anchor bolt with a longitudinal axis, at least one
action means on another, second terminal section of the anchor bolt
to bear the load, an expansion sleeve that surrounds the anchor
bolt, whereby the expansion body, on the radially outer side, is at
different distances from the longitudinal axis with reference to at
least one identical point on the longitudinal axis in a transfer
zone.
[0008] The expansion body of the anchor bolt therefore does not
have a rotationally symmetrical geometry with reference to the
longitudinal axis of the anchor bolt. Compared to a rotationally
symmetric geometry, on one hand the invention teaches that the
tendency of the cone to damage the borehole when it is hammered
into the borehole is reduced, so that according to the invention
the energy required for installation and in particular the number
of hammer blows required can be reduced. In addition, on account of
the design of the conical shape of the invention, a co-rotation of
the bolt during the application of the installation torque is
reduced. During the spreading or radially outward deformation of
the expansion sleeve with the expansion body, on the other hand,
different deformations or expansions of the expansion sleeve occur
in the tangential direction on the expansion body. As a result, the
expansion sleeve or the expansion body can dig into the borehole
wall or spread apart in a structural component with a very high
compression force on the wall of the borehole in spot locations, as
a result of which particularly large forces can thereby be absorbed
by the expansion anchor. As a result of this geometry of the
expansion body, manufacturing tolerances have only a very slight
influence on the forces that can be transmitted to the wall of the
borehole by the expansion anchor, so that reduced manufacturing
precision in the manufacture of the expansion body is sufficient,
which makes it possible to reduce manufacturing costs.
[0009] In particular, at least the transfer zone is corrugated or
serrated, for example with at least 3, 4 or 7, preferably 7 to 9,
corrugations or serrations and/or the distances between the at
least one point and the longitudinal axis differ by at least 1%,
2%, 3%, 4%, 5%, 10%, 15% or 20%. The corrugations are preferably
rounded by radii on their radial outside peaks. The serrations, on
the other hand, can have angled edges.
[0010] In an additional configuration, the corrugated or serrated
transfer zone occupies only a portion of the expansion body in the
axial direction. Alternatively, the entire expansion body can be
provided with corrugations or serrations.
[0011] The expansion body, in particular outside the transfer zone,
has a conical geometry.
[0012] In an additional embodiment, the transfer zone has an
essentially cylindrical shape and a longitudinal axis of the
cylinder is oriented coaxially with the longitudinal axis of the
anchor bolt. On account of the cylindrical transfer zone, the
expansion body does not have a conical shape in the transfer zone.
Therefore when the expansion sleeve with the expansion body is
expanded, first of all the expansion sleeve on the conical
expansion body expands radially outside the transfer zone and only
in the vicinity of a first rear end of the anchor bolt does the
transfer zone occur. At the beginning of the transfer zone, on
account of the corrugated or serrated geometry of the transfer
zone, as well as, in the transfer zone, different distances occur
between the longitudinal axis and the transfer zone. Consequently,
at the conclusion of the expansion process, the expansion anchor
will be radially expanded to different degrees. The result can be a
particularly effective anchoring of the expansion sleeve or of the
expansion body in a borehole wall of a structural component such as
a concrete wall or a concrete ceiling. Particularly high friction
forces can therefore be transmitted on account of the high friction
forces that occur in spot locations, and a positive or form-fitting
anchoring of the expansion sleeve and/or of the expansion body in
the borehole wall can be achieved.
[0013] Alternatively, the transfer zone can be essentially conical,
whereby the apex angle of the transfer zone is preferably smaller
than the apex angle of the expansion body outside the transfer
zone. The expansion body preferably has two conical areas with
different apex angles, whereby one of these areas contains the
transfer zone with the corrugations or serrations.
[0014] Preferably, in a cross-section of the transfer zone, the
points of the transfer zone which are at a maximum distance from
the longitudinal axis are connected by a virtual circumscribed
circle and the center of the circle corresponds to the longitudinal
axis and/or in a cross-section of the transfer zone, the points of
the transfer zone which are at a minimum distance to the
longitudinal axis are connected with a virtual inscribed circle and
the center of the inscribed circle corresponds to the longitudinal
axis.
[0015] Conventional expansion bodies described in the prior art are
rotationally symmetrical to the longitudinal axis. In one variant,
the expansion body outside the transfer zone is conical or in the
shape of a truncated cone and in the transfer zone the virtual
inscribed circle and/or circumscribed circle has an essentially
constant radius, i.e., the transfer zone is essentially
cylindrical. The radius of the virtual circumscribed circle is
greater than the maximum distance on the radial outside from the
longitudinal axis of an expansion body described in the prior art.
In one application of a rotationally symmetrical expansion body
described in the prior art, the expansion sleeve, on account of the
size or the geometry of the expansion sleeve, is associated with a
specified expansion body and the maximum distance of this
rotationally symmetrical expansion body known from the prior art is
therefore smaller than the radius of the circumscribed circle.
Consequently, during the expansion of the expansion body, when the
expansion anchor claimed by the invention is used, it expands
locally and radially to a greater extent at points that are at a
maximum distance from the longitudinal axis than with the use of an
expansion body described in the prior art. The radius of the
inscribed circle is therefore less than or essentially equal to,
i.e., with a variance of 10%, 5%, 3%, 2% or 1%, the maximum radius
or the maximum distance from the longitudinal axis on the expansion
body described in the prior art. In particular, the radius of the
circumscribed circle can be different by at least 1% from the
radius of the inscribed circle. As a result, with the use of an
expansion body claimed by the invention, the expansion body is also
expanded radially to a lesser extent or to an essentially equal
extent at the points that are at a minimum distance from the
longitudinal axis.
[0016] The radius of the virtual circumscribed circle
advantageously varies by less than 20%, 10% or 5% and/or the radius
of the virtual inscribed circle varies by less than 20%, 10% or
5%.
[0017] In an additional embodiment, the at least one action means
comprises a thread on the anchor bolt, a shim or a baseplate with a
boring and a nut.
[0018] In particular, the at least one action means is on a second
terminal section of the anchor bolt.
[0019] In an additional embodiment, the anchor bolt and/or the
expansion body and/or the at least one action means are made at
least partly or completely of metal, such as steel, for
example.
[0020] In an additional embodiment, the anchor bolt has a support
ring and the expansion body is supported on the support ring. When
the anchor bolt is unscrewed with the action means, e.g., the nut,
an axial fastening of the expansion sleeve is necessary so that the
expansion sleeve can expand. This expansion is accomplished by
means of a frictional connection, e.g., because the expansion
sleeve is additionally provided with projections.
[0021] In an additional variant of the invention, the expansion
sleeve is guided up to a shim, i.e., it is in contact with an
action means, and when the anchor bolt is unscrewed, the axial
fixing of the expansion sleeve is not provided by friction between
the borehole wall and the expansion sleeve but as a result of the
fact that the expansion sleeve is in contact with at least one
action means, e.g., a shim.
[0022] One exemplary embodiment of the invention is described in
greater detail below with reference to the accompanying
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a side view of an expansion anchor;
[0024] FIG. 2 is a cross-section A-A as illustrated in FIG. 1 of a
transfer zone of the expansion anchor; and
[0025] FIG. 3 is a side view of an additional expansion anchor.
DETAILED DESCRIPTION OF THE DRAWINGS
[0026] An expansion anchor 1 illustrated in FIG. 1 is used to
fasten workpieces to a structural component. A boring is machined
into the structural component (not shown) and to fasten the
workpiece the expansion anchor 1 is introduced or hammered into
this boring. The structural component can be a concrete wall or the
concrete ceiling of a building, for example.
[0027] The expansion anchor 1 comprises an anchor bolt 2. The
anchor bolt 2 has a first end 5 with a first terminal section 6 and
a second end 7 with a second terminal section 8. When the expansion
anchor 1 is introduced into a wall borehole of the structural
component, for example when it is hammered by means of a hammer,
the first end 5 is inserted into the borehole and a second end 7 or
a second terminal section 8 of the anchor bolt 2 remains outside
the wall of the borehole. On the first terminal section 6 which is
one piece with the anchor bolt 2, there is a conical expansion body
3. Between the expansion body 3 and a support ring 15 which is one
piece with the anchor bolt 2, an expansion sleeve 4 is located
coaxially around the anchor bolt 2. The expansion sleeve 4 is in
contact with the support ring 15, so that when the expansion anchor
1 is hammered into the borehole wall and as a result of the
resulting friction forces between the borehole wall and the
expansion sleeve 4, the expansion sleeve 4 is not displaced on the
anchor bolt 2 toward the second end 7 on account of its contact
with the support ring 15.
[0028] The expansion sleeve 4 has a plurality, e.g., three or five,
slots 16 that run in the direction of a longitudinal axis 10 of the
anchor bolt 2 so that on account of the axial longitudinal slots
16, the expansion sleeve 4 has a plurality of expansion segments
17. On the expansion sleeve 4, in particular the expansion segments
17 are in the form of first projections 18 and second projections
19. The first projections 18 are closer to the first end 5 of the
anchor bolt 2 than the second projections 19. The first and second
projections 18, 19 also preferably have different geometries.
[0029] Located on the second terminal section 8 of the anchor bolt
2 are three action means 20. The action means 20 are a thread 21
machined into the anchor bolt 2, a shim 22 and a nut 23. The nut 23
has a female thread which is not shown and which is engaged in the
male thread 21 on the anchor bolt 2.
[0030] The expansion body 3 is provided on its radial outside with
a transfer zone 9. The transfer zone 9 shown in a section A-A in
FIG. 1, i.e., a section perpendicular to the plane of the drawing
in FIG. 1 and perpendicular to the longitudinal axis 10 of the
anchor bolt 2, is corrugated with a plurality of corrugations. The
expansion body 3, in the transfer zone 9, is therefore at different
distances from the longitudinal axis 10. On the peaks of the
corrugations in the transfer zone 9, points 11 therefore occur
which are at a maximum distance from the longitudinal axis 10, and
in the valleys of the corrugations, points 12 which are at a
minimum distance from the longitudinal axis 10. The points 11 which
are at a maximum distance are thereby connected to one another by a
virtual circumscribed circle 13 which is shown in a broken line in
FIG. 2, and the points 12 which are at a minimum distance from the
longitudinal axis 10 are connected to one another on a virtual
inscribed circle 14 which is shown in a broken line in FIG. 2. The
expansion body 3 outside the transfer zone 9 is conical, i.e., a
section along section A-A perpendicular to the plane of the drawing
in FIG. 1 and perpendicular to the longitudinal axis 10 (not shown)
therefore represents a circle with a radius that increases toward
the first end 5. The transfer zone 9 is essentially cylindrical,
i.e., preferably with a deviation of less than 20%, 10%, 5% or 2%,
ignoring the corrugations or serrations, so that in a section along
the section A-A perpendicular to the plane of the drawing in FIG. 1
and perpendicular to the longitudinal axis 10 in the transfer zone
9, the virtual circumscribed and inscribed circles 13, 14 have a
constant radius at different sections in the direction of the
longitudinal axis 10.
[0031] To fasten workpieces to the expansion anchor 1, the
expansion anchor 1 is introduced or hammered into a borehole or a
boring in a structural component. After the insertion of the
expansion anchor 1 into this borehole, the first end 5 is located
inside the borehole and the second end 7 is located outside the
borehole. By means of the action means 20, in which the nut 23 with
the thread 21 is screwed, the anchor bolt 2 and thus also the
expansion body 3 are screwed outward in the axial direction with
reference to the longitudinal axis 10, so that on account of the
axial fixing of the expansion sleeve 4 by the frictional forces
between the expansion sleeve 4 in the borehole as well as on
account of the projections 18, 19 which make possible a
form-fitting connection, with the expansion body 3 the expansion
sleeve 4 is expanded radially outward in the expansion segments 17
so that frictional forces and a bias force occur between the
expansion sleeve 4 and/or the expansion body 3 and the borehole
wall, to achieve an axial fixing of the expansion body 3 in the
borehole wall for an axial fastening of the expansion anchor 1 in
the borehole (not shown) of the structural component (not
shown).
[0032] On account of the corrugated transfer zone 9 on the radial
outside of the expansion body 3 in the vicinity of the first end 5,
i.e., on the first terminal section 6 of the anchor bolt 2, a
different radial bias or digging in of the expansion body 3 and/or
of the expansion sleeve 4 into the borehole wall occurs. As a
result, in the vicinity of the points 11 which are at the maximum
distance from the longitudinal axis 10, significantly greater local
bias forces occur than in the points 12 which are at the minimum
distance from the longitudinal axis 10. In spot locations, there is
a greater digging in as well as a form-fitting connection between
the borehole wall and the expansion sleeve 4 and/or the expansion
body 3. Even under difficult conditions, very large axial tensile
forces can therefore be absorbed by the expansion anchor 1 because
very great friction forces can be absorbed by the expansion sleeve
4 and/or the expansion body 3, and a very good form-fitting
connection exists between the expansion sleeve 4 and/or the
expansion body 3 as well as the borehole wall.
[0033] An additional exemplary embodiment of an anchor is
illustrated in FIG. 3. The example illustrated in FIG. 3 differs
from the embodiment illustrated in FIG. 1 in that in FIG. 3, the
transfer zone 9 with the corrugations or separations is conical,
whereby the apex angle .alpha.1 in the transfer zone 9 is smaller
than the apex angle .alpha.2 outside the transfer zone 9.
[0034] Overall, the expansion anchor 1 by the invention has
significant advantages. On account of the corrugated geometry of
the transfer zone 9 on the expansion body 3, tangentially a
different bias or digging into the borehole wall is achieved in the
peripheral direction of a circumscribed circle 13 or of an
inscribed circle 14. In addition, the energy required to hammer in
the anchor is significantly reduced and the anchor is protected to
a greater extent against rotation inside the borehole. As a result,
different factors that result from the manufacturing tolerances of
the expansion body 3 have only a minor influence on the forces that
can be transmitted by the expansion anchor 1, so that the expansion
body 3 can be manufactured more economically with less-precise
manufacturing and using alternative manufacturing methods.
* * * * *