U.S. patent application number 13/511649 was filed with the patent office on 2012-09-27 for chair for a concrete lifting anchor.
This patent application is currently assigned to CASNE VERIGE PTY LTD. Invention is credited to Robert Sladojevic.
Application Number | 20120240483 13/511649 |
Document ID | / |
Family ID | 42232807 |
Filed Date | 2012-09-27 |
United States Patent
Application |
20120240483 |
Kind Code |
A1 |
Sladojevic; Robert |
September 27, 2012 |
CHAIR FOR A CONCRETE LIFTING ANCHOR
Abstract
A chair for supporting an edgelift anchor for use in lifting a
concrete component, said anchor comprising a head portion engagable
with a clutch of a lifting system, and a body portion for embedment
with the concrete component, wherein the chair has surfaces
configured for supporting the edgelift anchor relative to a casting
surface during casting of the concrete component.
Inventors: |
Sladojevic; Robert; (Cherry
Gardens, AU) |
Assignee: |
CASNE VERIGE PTY LTD
Terrace Kent Town
AU
|
Family ID: |
42232807 |
Appl. No.: |
13/511649 |
Filed: |
November 25, 2009 |
PCT Filed: |
November 25, 2009 |
PCT NO: |
PCT/AU09/01540 |
371 Date: |
May 23, 2012 |
Current U.S.
Class: |
52/125.4 |
Current CPC
Class: |
E04G 21/142
20130101 |
Class at
Publication: |
52/125.4 |
International
Class: |
E04G 21/14 20060101
E04G021/14 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 2, 2008 |
AU |
2008906245 |
Claims
1.-15. (canceled)
16. A collar for an anchor for use in lifting a concrete component,
said anchor comprising a head portion engageable with a clutch of a
lifting system, and a body portion for embedment within the
concrete component, the collar including an attachment portion for
attaching the collar to the head portion of the anchor, and an
abutment portion adapted to provide a clutch abutment surface for
limiting rotation of the clutch relative to the anchor.
17. A collar as claimed in claim 16, wherein when the collar is
fitted to the anchor the abutment portion forms the clutch abutment
surface as a shoulder adjacent the anchor.
18. A collar as claimed in claim 17, wherein the clutch abutment
surface is formed as a shoulder standing proud of the head portion
for limiting rotation of the clutch about an eye of the head
portion.
19. A collar as claimed in claim 18, wherein the abutment portion
provides a pair of opposed shoulders on the head portion for
limiting rotation of the clutch about the eye in both directions of
rotation.
20. A collar as claimed in claim 19, including a gap between the
shoulders which coincides with the eye of the head portion to allow
passage of the clutch through the eye.
21. A collar as claimed in claim 16, wherein the abutment portion
is formed by an edge of the collar.
22. A collar as claimed in claim 16, wherein the collar fits around
the head portion, and is held to the head portion by way of a press
fit.
23. A collar as claimed in claim 16, wherein the collar is
generally C-shaped.
24. A collar as claimed in claim 16, including at least one shear
bar attached to the collar.
25. A collar as claimed in claim 24, wherein the shear bar engages
in a groove of the collar.
26. A collar as claimed in claim 24, wherein the shear bar is
welded to the collar.
27. A collar as claimed in claim 24, wherein the shear bar is
formed in a generally wave-like shape, with oscillations in a
direction generally perpendicular to a central axis of the anchor
when the collar is fitted to the anchor.
28. A collar as claimed in claim 27, including a second shear bar,
wherein a major axis of the second shear bar is generally parallel
to a major axis of the first shear bar and is substantially a
mirror image of the first shear bar when viewed from an end of the
anchor.
29. An anchor for use in lifting a concrete component, said anchor
comprising a single length of wire bent to form a head portion
engageable with a clutch of a lifting system, and a body portion
for embedment within the concrete component, wherein the anchor has
a collar attached to the head portion to provide clutch abutment
surfaces for limiting rotation of the clutch relative to the
anchor, the collar being a collar as claimed in claim 16.
30. An anchor system for use in lifting a concrete component, the
assembly comprising an anchor formed from a one-piece elongate
element shaped to form a head portion engageable by a clutch of a
lifting system and a body portion for embedment within the concrete
component; and a collar carried by the head portion of the anchor
to define at least one clutch abutment surface for limiting
rotation of the clutch relative to the anchor.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a chair for a concrete component
lifting anchor and, more particularly but not exclusively, to a
height-adjustable chair for an edgelift anchor.
BACKGROUND OF THE INVENTION
[0002] It is known to lift a concrete panel by way of an edgelift
anchor embedded within a side edge of the concrete panel during
casting of same. Typically, the edgelift anchor is held in place
during casting by supporting the anchor on a sideform used for
casting the concrete panel. However, the applicant has identified
that edgelift anchors supported in this way are difficult to
support adequately, and are prone to being embedded incorrectly
relative to the concrete panel, particularly due to movement of the
anchor under its own weight, and due to movement of the
sideform.
[0003] Concrete panels may also be lifted by a facelift anchor
embedded within a face of the concrete panel during casting. The
applicant has determined that existing apparatus for supporting a
facelift anchor during casting of a concrete panel typically lack
the ability to conveniently adjust the height of the anchor
relative to the concrete panel. Accordingly, the anchor may be set
to an incorrect depth within the concrete component.
[0004] Examples of the invention seek to solve, or at least
ameliorate, one or more disadvantages of previous apparatus for
supporting lifting anchors during casting of concrete
components.
SUMMARY OF THE INVENTION
[0005] In accordance with one aspect of the present invention,
there is provided a chair for supporting an edgelift anchor for use
in lifting a concrete component, said anchor comprising a head
portion engagable with a clutch of a lifting system, and a body
portion for embedment with the concrete component, wherein the
chair has surfaces configured for supporting the edgelift anchor
relative to a casting surface during casting of the concrete
component.
[0006] Preferably, the chair has first and second parts configured
to support the anchor relative to the casting surface at a first
height using the first part on its own, or in conjunction with the
second part to provide a range of further heights. More preferably,
the first and second parts are arranged so as to be used in
conjunction in one configuration to support the anchor at a second
height relative to the casting surface, and in another
configuration in which the second part is inverted to support the
anchor at a third height relative to the casting surface.
[0007] Preferably, the chair is configured to support the anchor
such that a longitudinal axis of the anchor is substantially
parallel to the casting surface.
[0008] In one example, the chair is provided in combination with an
edgelift anchor supported by the chair, wherein the body portion of
the anchor has a plane oriented substantially parallel to the
casting surface.
[0009] In another example, the chair is provided in combination
with an edgelift anchor supported by the chair, wherein the body
portion of the anchor has a plane oriented substantially
perpendicular to the casting surface.
[0010] Preferably, the head portion of the anchor has a plane
oriented substantially perpendicular to the casting surface.
[0011] In accordance with another aspect of the present invention,
there is provided a chair for supporting an anchor for use in
lifting a concrete component, said anchor comprising a head portion
engagable with a clutch of a lifting system, and a body portion for
embedment with the concrete component, wherein the chair has first
and second parts configured to support the anchor, during casting,
relative to the casting surface at a first height using the first
part on its own, or in conjunction with the second part to provide
a range of further heights.
[0012] Preferably, the first part has a support for the anchor, and
the second part is arranged for supporting the first part relative
to the casting surface, and wherein the second part is able to be
interchanged with either a different second part or the same second
part when inverted to selectively support the anchor at a range of
different heights relative to the casting surface. More preferably,
each different second part is able to selectively support the
anchor at two different heights relative to the casting surface by
inverting the second part. Even more preferably, each second part
is marked on opposite sides to represent a height at which the
anchor is supported when the second part is used in conjunction
with the first part, with the second part being in a non-inverted
and/or an inverted configuration.
[0013] Preferably, the chair is adapted for supporting a void
former when fitted to the anchor. More preferably, the chair has
one or more arms which extend to directly support the void
former.
[0014] Preferably, the chair is adapted to support a reinforcement
mesh of the concrete component. More preferably, the chair includes
an insert for supporting the reinforcement mesh. Even more
preferably, the chair includes a range of inserts which are
interchangeable for supporting the reinforcement mesh at different
heights relative to the anchor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The invention is described, by way of non-limiting example
only, with reference to the accompanying drawings in which:
[0016] FIG. 1 is a perspective view of a lifting anchor having a
collar;
[0017] FIG. 2 is a perspective view of the anchor of FIG. 1, shown
with an associated chair;
[0018] FIG. 3 is a perspective view of the anchor, shown with the
chair fitted thereto;
[0019] FIG. 4 is a side view of the anchor, with the chair fitted
thereto;
[0020] FIG. 5 is a top view of the anchor, with the chair fitted
thereto;
[0021] FIG. 6 is a perspective view of the chair shown in
isolation, in a deconstructed condition;
[0022] FIG. 7 is a perspective view of an edge of a concrete
component with the anchor embedded therein;
[0023] FIG. 8 is a head portion end perspective view of another
anchor, shown in place relative to a chair for supporting the
anchor;
[0024] FIG. 9 is a body portion end perspective view of the anchor
and chair shown in FIG. 8;
[0025] FIG. 10 is a top view of the anchor and chair shown in FIGS.
8 and 9;
[0026] FIG. 11 is a side view of the anchor and chair shown in
FIGS. 8 to 10;
[0027] FIG. 12 is a head portion end view of the anchor and chair
shown in FIGS. 8 to 11;
[0028] FIGS. 13a to 13d show various views of the anchor of FIGS. 8
to 12, shown in place relative to a chair for supporting the
anchor, the chair also supporting a tension bar of the anchor;
[0029] FIG. 14 is a perspective view of the chair shown in FIGS.
13a to 13d, shown with a pair of inserts for supporting a
reinforcement mesh of the concrete component;
[0030] FIG. 15 is a perspective view of the chair of FIG. 14, shown
with the inserts in place and supporting a reinforcement mesh;
[0031] FIG. 16 is a side view of the chair of FIG. 14 with inserts
in place, supporting the reinforcement mesh;
[0032] FIG. 17 is a perspective view of the chair of FIG. 14 shown
with an interchangeable insert of a different height;
[0033] FIG. 18 is a side view of the chair and insert of FIG. 17,
shown supporting the reinforcement mesh at a different height
relative to the anchor;
[0034] FIGS. 19a to 19d are perspective, side, top and end views of
a chair supporting an anchor, together with a void former fitted to
the anchor;
[0035] FIGS. 20a to 20d are perspective, side, top and end views of
an alternative chair shown supporting an anchor, together with a
void former fitted to the anchor; and
[0036] FIGS. 21a to 21d are perspective, side, top and end views of
a further alternative chair shown supporting an anchor, together
with a void former fitted to the anchor.
DETAILED DESCRIPTION
[0037] With reference to FIG. 1, there is shown an anchor 10 for
use in lifting a concrete component 12. The anchor 10 shown is in
the form of an edge lift anchor, however it will be appreciated by
those skilled in the art that alternative examples may be used with
other types of anchors such as, for example, a face lift
anchor.
[0038] The anchor 10 comprises a single length of wire 14 bent to
form a head portion 16 engagable with a clutch of a lifting system,
and a body portion 18 for embedment with the concrete component 12.
The wire 14 is bent such that opposed legs 20, 22 of the body
portion 18 extend in a plane substantially perpendicular to a plane
of the head portion 16. By virtue of the wire 14 being bent in this
way, the anchor 10 is able to be arranged such that the opposed
legs 20, 22 lie in a plane substantially parallel to a central
plane of the concrete component 12, while the head portion 16 is
oriented substantially perpendicularly to the central plane of the
concrete component 12. Advantageously, this enables the anchor 10
to be located lower in the concrete component 12 to facilitate edge
lifting of the concrete component 12, while facilitating a broad
spread of the opposed legs 20, 22 within the concrete component
12.
[0039] As the legs 20, 22 are spread outwardly from a central axis
24, the load applied to the anchor 10 is distributed through a
larger region of the concrete component 12 than is possible with a
typical concrete anchor having parallel legs. Accordingly, this
reduces the likelihood of the concrete component 12 failing during
lifting, as a large region of the concrete component 12 must fail
for the anchor 10 to be torn out during lifting. Each of the legs
20, 22 may be formed with a wave-like configuration by
incorporating a series of ripple bends to provide additional
anchorage of the anchor 10 within the concrete component 12.
Advantageously, the ripple bends prevent the legs 20, 22 from being
withdrawn from the concrete, by applying compression to the
concrete during lifting. As such, the opposed legs 20, 22 are able
to provide the same function as ancillary tension bars which have
been used in existing lifting anchors.
[0040] To achieve the perpendicular configuration, the head portion
16 in the example shown is twisted through an angle of 270 degrees
relative to the body portion 18 about the central axis 24 of the
anchor 10. In alternative anchors, to achieve a perpendicular
configuration the head portion may be twisted through an angle of
90 degrees (or, more generally, an angle of 90+180x, where x is a
whole number) relative to the body portion 18 about the central
axis 24 of the anchor 10. The central axis 24 is in the plane of
the head portion 16. In this way, the plane of the head portion 16
is perpendicular to the plane of the body portion 18.
[0041] It will be understood that in alternative examples, the body
portion 18 may be rotated about the central axis 24 relative to the
head portion 16 such that the plane of the body portion 18 is out
of the plane of the head portion 16 by an angle other than 90
degrees. In particular alternatives, this angle may be
approximately 60, 45, 30 or 15 degrees, as may be appropriate
depending on the shape and/or orientation of the concrete component
12.
[0042] The head portion 16 of the anchor 10 may also be tilted
upwardly/downwardly out of the plane of the legs 20, 22. This
tilting of the head portion 16 may be achieved by bending the
anchor on site, and may be advantageous when using the anchor 10 to
lift concrete components having angled edges. In particular
examples, the edge of the concrete panel may be at an angle of 9
degrees, 15 degrees, 22.5 degrees, 30 degrees or 45 degrees to a
plane perpendicular to the central axis 24, and the head portion 16
may be bent relative to the legs 20, 22 at a corresponding
angle.
[0043] The anchor 10 includes a collar 26 adapted to fit around the
head portion 16, as shown in FIG. 1. The collar 26 forms abutment
shoulders 28 at upper and lower locations of the head portion 16
for cooperation with a body of the clutch to limit clutch rotation
relative to the anchor 10.
[0044] More specifically, the collar 26 includes an attachment
portion 58 for attaching the collar 26 to the lifting anchor 10,
and an abutment portion 60 adapted to provide a clutch abutment
surface for limiting rotation of a clutch relative to the lifting
anchor 10. The attachment portion 58 is arranged for attaching the
collar 26 to the head portion 16 of the lifting anchor 10. When the
collar 26 is fitted to the anchor 10, the clutch abutment surface
is formed as an abutment shoulder 28 adjacent each side of the head
portion 16 for limiting rotation of the clutch about an eye 62 of
the head portion 16, in both directions of rotation. The collar 26
may include a gap 64 between the shoulders 28 which coincides with
the eye 62 of the head portion 16 to allow passage of the clutch
through the eye 62.
[0045] The collar 26 is generally C-shaped, including a pair of
clasps for coupling to opposed wire lengths of the head portion 16,
with a connecting strip 66 between the clasps. Each clasp
terminates in a tab 68 which secures the collar 26 to the head
portion 16 by way of a hard press fit. The abutment portion 60 is
formed by an edge of the collar 26, at each of the clasps.
[0046] The collar 26 includes a pair of shear bars 30, 32 attached
to the collar 26. The shear bars 30, 32 extend generally
perpendicularly to the central axis 24, generally in the plane of
the body portion 18. These shear bars 30, 32 assist in preventing
shear failure of the concrete component 12 during lifting, and
provide improved anchorage of the anchor 10 within the concrete
component 12. Each of the shear bars 30, 32 is formed in a
generally wave-like shape, with lateral oscillations 34 in a
direction generally perpendicular to the central axis 24 of the
anchor 10. A second one of the shear bars 30 is located under a
first one of the shear bars 32, and is reversed such that the
second shear bar 30 is substantially a mirror image of the first
shear bar 32 when viewed from an end of the anchor 10. The shear
bars 30, 32 may be positively held in place relative to the head
portion 16 by engagement of the shear bars 30, 32 within grooves 36
formed in the collar 26. The grooves 36 formed on opposite sides of
the collar 26 may be formed in a correspondingly offset
configuration so as to positively locate the shear bars 30, 32 in
the arrangement shown. Alternatively, the shear bars 30, 32 may be
fixed relative to the head portion 16 by spot welding of the shear
bars 30, 32 to the collar 26.
[0047] The applicant has determined that the collar 26 is
particularly suited for use in providing a concrete component
lifting anchor formed of bent wire with clutch abutment surfaces
for limiting rotation of a clutch relative to the lifting anchor.
This is because there is not the same ability in providing anchors
formed of bent wire with shoulders as there is with anchors cut
from plate. However, it is possible for collars formed in
accordance with other examples of the present invention to be used
with anchors formed from plate, and such collars may provide
various advantages over cut abutment shoulders. In particular,
using a collar according to an example of the present invention
provides the ability to interchange collars to change the
size/shape of abutment shoulders, and provides a convenient way to
attach shear bars to the anchor.
[0048] The collar 26 is preferably formed of metal, in particular
from folded steel. In other examples, the collar may be formed from
plastic.
[0049] Returning to the actual anchor itself, the length of wire 14
from which the anchor 10 is formed may be a length of metal bar
which is bent to form the anchor 10. The length of metal bar may be
drawn from a coil. Advantageously, by virtue of the anchor 10 being
formed from metal bar, material wastage is minimised, and the
anchor 10 is manufactured in a particularly cost-effective
manner.
[0050] In particular, the head portion 16 is formed by bending the
metal bar around a forming piece, the forming piece being a pin
having a size corresponding to the size of a clutch portion to pass
through the head portion 16. By virtue of this forming process, any
variation in the dimensions (particularly the diameter) of the
metal bar will not alter the size of the aperture in the head
portion 16. Accordingly, it is possible to provide a superior
tolerance for an effective, rigid coupling between the clutch and
the anchor, thus avoiding a sloppy coupling between the anchor and
the clutch. In other words, variation in the wire does not affect
quality of engagement between the anchor and the clutch.
[0051] Also, by virtue of the anchor 10 being formed of from round
cross-section metal bar, there is a single point of contact between
the clutch portion and the anchor 10, avoiding the problems
associated with skewed prior art anchors cut from metal plate which
tend to transfer undesirable forces to the concrete component
12.
[0052] With reference to FIG. 2, the anchor 10 forms part of an
anchor assembly 38 which includes a chair 40. The chair 40
comprises a first, upper, part 44 and a second, lower, part 46
which are fitted together, with the first part 44 having clips 48
for holding the anchor 10 in place relative to the chair 40, as
shown in FIGS. 3 to 5. FIG. 6 shows a detailed view of the first
part 44 and the second part 46 in isolation. As the body portion 18
is in a plane perpendicular to the plane of the head portion 16,
when in situ the opposed legs 20, 22 do not extend below the head
portion 16, thus allowing the anchor 10 to be mounted in a
relatively low position within the concrete component 12, while
ensuring the opposed legs 20, 22 are embedded inside the concrete
component 12. More particularly, the chair 40 is arranged for
supporting the anchor 10 within the concrete component 12 during
casting, with the plane of the body portion 18 coplanar or oriented
substantially parallel to a central plane of the concrete component
12.
[0053] By virtue of the plane of the body portion 18 being coplanar
with or substantially parallel to a central plane of the concrete
component 12, it is possible for the body portion 18 to be located
at or within a neutral axis of the concrete component 12 so as to
avoid having the anchor embedded in regions of the concrete
component 12 which are under high compression and/or tension during
lifting. This may assist in avoiding failure of the concrete
component 12 during lifting, and may enable lifting of concrete
panels at a stage more premature (relative to the time of casting)
than is required for lifting using existing concrete anchors.
[0054] Furthermore, the feature of the plane of the body portion 18
being coplanar with or substantially parallel to the central plane
of the concrete component 12 enables the anchor to be used with
concrete panels much thinner than is required for lifting using
existing concrete anchors which extend transversely across a
substantial portion of the thickness of the panel.
[0055] FIG. 7 shows an edge of a concrete component 12 in which the
anchor 10 is embedded. A void 56 is formed around the head portion
16, and facilitates engagement of a clutch with the anchor 10 for
lifting of the concrete component 12. Although in this drawing the
anchor 10 is shown as being mounted in a central part of the
concrete component 12, it will be appreciated by those skilled in
the art that the anchor 10 may be mounted within the concrete
component 12 in a lower location such that the plane of the body
portion 18 is below the central plane of the concrete component
12.
[0056] Advantageously, the chair 40 has surfaces in the form of the
clips 48 and feet 70 configured for supporting the anchor 10
relative to a casting surface during casting of the concrete
component 12. Where the chair 40 is used including its second part
46, the surfaces configured for supporting the anchor also include
upper and lower surfaces 72, 74 of the foot spacers 76. The first
and second parts 44, 46 are configured to support the anchor 10
relative to the casting surface at a first height using the first
part 44 on its own, or in conjunction with the second part 46 to
provide a range of further heights. This is achieved by supporting
the anchor 10 using the first part 44, the feet 70 of which sit
directly on the casting surface, or by using the second part 46 in
the manner shown in FIGS. 3 and 4. The first and second parts 44,
46 may be used in conjunction in this configuration to support the
anchor at a second height relative to the casting surface, and in
another configuration in which the second part 46 is inverted so as
to support the anchor 10 at a third height relative to the casting
surface. As can be seen in FIGS. 2 and 3, the second part 46 is
marked on opposite sides to indicate a height at which the anchor
10 is supported when the second part 46 is used in conjunction with
the first part 44, with the second part being in a non-inverted
and/or an inverted configuration. In particular, the markings
indicate the height at which the anchor 10 is supported when the
respective side of the second part 46 faces upwardly.
[0057] As can be seen in the side view of FIG. 4, the chair 40 is
configured to support the anchor 10 such that the longitudinal
central axis 24 of the anchor 10 is substantially parallel to the
casting surface. In this way, the anchor 10 is oriented correctly
for lifting of the concrete component 12 by the head portion 16
after casting. In the example shown in FIGS. 3 to 5, the anchor 10
is supported by the chair 40 such that the body portion 18 of the
anchor 10 has a plane oriented substantially parallel to the
casting surface. In contrast, in the example shown in FIGS. 8 to
12, the anchor 10 is supported by the chair 40 such that the body
portion 18 of the anchor 10 has a plane oriented substantially
perpendicular to the casting surface. The anchor 10 shown in FIGS.
8 to 12 is a typical edgelift anchor formed from plate by a process
of cutting, however it may be supported by a chair 40 formed in
accordance with the present invention in the manner shown. Like
features are denoted with like reference numerals.
[0058] As the anchor 10 shown in FIGS. 8 to 12 is cut from plate
and is substantially planar such that the head portion 16 and body
portion 18 rest in the same plane, it is necessary for the plane of
the body portion 18 to be substantially perpendicular to the plane
of the casting surface in order for the head portion 16 to have the
correct orientation for lifting of the concrete component 12.
Accordingly, the first part 44 is formed with slots 78 so as to
support the anchor 10 in this perpendicular orientation. The first
part 44 is also provided with holders 80 for holding the shear bars
30, 32 in configuration. In this way the shear bars 30, 32 are held
in place sufficiently without spot welding to the collar 26 as in
the example shown in FIGS. 1 to 7.
[0059] Although FIGS. 8 to 12 do not show a second part 46 of the
chair 40, a second part 46 similar to the one shown in FIGS. 2 to 6
may be used.
[0060] The casting surface may be a ground surface against which
the concrete component is formed, or an underlying surface (eg. of
another concrete component) which is used as a surface for forming
the concrete component in which the anchor 10 is to be
embedded.
[0061] Advantageously, the chair 40 provides an apparatus which
enables convenient height adjustment of the anchor 10 relative to
the casting surface so that it can be embedded at a desired
location within the concrete component 12. The second part 46 is
able to be interchanged with other second parts to provide
different heights relative to the casting surface. Each second part
46 may be configured asymmetrically in a manner similar to the
second part 46 shown in FIGS. 2 to 6, so as to provide two
different heights relative to the casting surface by inversion.
[0062] While various embodiments of the present invention have been
described above, it should be understood that they have been
presented by way of example only, and not by way of limitation. It
will be apparent to a person skilled in the relevant art that
various changes in form and detail can be made therein without
departing from the spirit and scope of the invention. Thus, the
present invention should not be limited by any of the above
described exemplary embodiments.
[0063] In particular, although the example anchor depicted in the
drawings has an angle between the plane of the legs and the plane
of the head portion of approximately 90 degrees, it will be
understood that in alternative examples the angle between the plane
of the legs and the plane of the head portion may take other
values, for example 60, 45, 30 or 15 degrees. This angle may be
dictated by the shape and/or orientation of the concrete
component.
[0064] With reference to FIGS. 13a to 13d, the anchor 10 cut from
metal plate material may be provided with a tension bar 82, and the
chair 40 may have angled clips 84 for supporting the tension bar
82. As shown in these drawings, the anchor 10 may be provided with
only a single shear bar 30, and the chair 40 may be provided with
only a single set of holders 80 for holding the shear bar 30.
[0065] With reference to FIGS. 14 to 18, the chair 40 may be
provided with one or more inserts 86 for supporting a reinforcement
mesh 88 of the concrete component. The inserts 86 may be shaped so
as to be inserted into the feet 70 of the chair 40, as shown. With
reference to FIGS. 15 and 16, when the inserts 86 are mounted in
place on the chair 40, upper surfaces 90 are arranged so as to
support the reinforcement mesh 88. As can be seen, the inserts 86
are arranged such that the upper surfaces 90 support the
reinforcement mesh 88 approximately midway between the legs of the
anchor 10. However, in some circumstances, it may be desirable to
support the reinforcement mesh 88 at a different location relative
to the anchor 10, and the inserts 86 may be interchangeable with
one or more other inserts 92 as shown in FIGS. 17 and 18. The
interchangeable inserts may be in two pieces as shown in FIGS. 14
to 16, or may be joined in a single piece, as shown in FIGS. 17 and
18. With reference to FIG. 18, the insert 92 is arranged such that
the upper surfaces 90 support the reinforcement mesh 88
substantially in line with an upper surface of the anchor 10.
[0066] FIGS. 19a to 19d show a chair 40 in accordance with a
variation, wherein the chair 40 includes a plurality of support
arms 94 for supporting a void former 96 mounted to the head portion
16 of the anchor 10. The support arms 94 support the void former 96
in such a way that the void former 96 can be removed from the chair
40 after casting of the concrete component, thereby leaving a void
for inserting a lifting clutch through the eye of the head portion
16. FIGS. 20a to 20d show an alternative chair 40 which has support
arms 94 configured to extend from the holders 80 for supporting the
void former. FIGS. 21a to 21d show a further alternative chair 40
which has support arms 94 arranged to support the void former 96 at
various locations at an underside of the void former 96.
[0067] Advantageously, this then does not place differential
movement between the anchor and the void former through movement of
the reinforcement mesh, as has occurred previously through the
anchor body only being tied to the mesh via shear and tension bars.
The chair provides direct localised support to the mesh at the
anchor location and as such eliminates this differential movement
whilst also eliminating the need for custom bent chairs under the
anchor and under the mesh which all have different heights. The
drawings show mesh supported as most common typical central mesh
and then also supporting top mesh over the lifter in the case of
two layers of mesh. In the case of two layers of mesh the bottom
mesh is under the anchor and hence is not supported by the
anchor--only the top mesh would be.
[0068] In previous systems, void formers are supported from the
sideforms while the anchor body is connected to the mesh causing
differential movement between the anchor body and void former
including differential height placement and torsion between the
two. This then results in movement away from the perfect design fit
and causes poor clutch fit into the panel's edge in engagement with
the anchor. This is currently a substantial problem in the
industry. However, by supporting the anchor and void former
together in perfect fit by the chair, this problem is
eliminated.
[0069] The reference in this specification to any prior publication
(or information derived from it), or to any matter which is known,
is not, and should not be taken as an acknowledgment or admission
or any form of suggestion that that prior publication (or
information derived from it) or known matter forms part of the
common general knowledge in the field of endeavour to which this
specification relates.
[0070] Throughout this specification and the claims which follow,
unless the context requires otherwise, the word "comprise", and
variations such as "comprises" and "comprising", will be understood
to imply the inclusion of a stated integer or step or group of
integers or steps but not the exclusion of any other integer or
step or group of integers or steps.
* * * * *