NZ723905A - Lifting device - Google Patents

Abstract

lifting anchor for embedding in a concrete building component includes a substantially planar anchor body being of an integral construction and including a first portion and a second portion, each for embedding in the concrete building component. The first portion includes a transverse aperture therethrough adapted, in use, to co-operate with a clutch to allow for lifting of the building component. The second portion includes a transverse aperture therethrough adapted to receive and releasably retain a reinforcement bar. The anchor further includes at least one elongate member extending from the second portion and preferably offset from the first portion. erethrough adapted, in use, to co-operate with a clutch to allow for lifting of the building component. The second portion includes a transverse aperture therethrough adapted to receive and releasably retain a reinforcement bar. The anchor further includes at least one elongate member extending from the second portion and preferably offset from the first portion.

Description

LIFTING DEVICE FIELD OF THE INVENTION The present invention relates, in general terms, to improvements in lifting anchors. More particularly, but not exclusively, the invention relates to an improved form of lifting anchor for use in edge lifting or tilt-up of precast concrete panels and the like structural elements.

BACKGROUND OF THE INVENTION Nowadays in the construction industry it has increasingly more become the practice for building components, as for example constructed from reinforced concrete, to be pre-cast off-site and then transported to a construction site for actual installation.

So as to allow for such transport an accepted practice is to have, preferably located at or in the vicinity of relevant edge surfaces of a building component, one or more what are referred to as lifting anchors. By way of example only, in a reinforced concrete wall panel of any significant dimensions two or more such lifting anchors may be sited/located along at least two adjoining and mutually perpendicular edges of the panel. The anchors will be embedded in recesses formed or provided in the building component using what are referred to as void formers. Each anchor is embedded in the building component in such a way as to have an end portion thereof left exposed to allow for attachment of a hoisting shackle or the like as, and when, required.

Currently in Australia and New Zealand a commonly-employed method and procedure allowing for edge lifting or tilt up of pre-cast concrete panels utilizes what are referred to as hairpin-style lifters, such having two legs which, in use, are disposed either side of the reinforcement mesh included within such a panel during the course of formation thereof. It has been found, however, that having those legs disposed on opposed sides of an individual wire of such a mesh can give rise to difficulties in installation, since the mesh will need to be in fact lifted to allow for insertion of the leg on the lower side thereof. Furthermore, small pieces of reinforcing bar are typically needed to tie the lifting anchor to the mesh itself and to allow correct spacing between the mesh and the legs of an anchor.

SUMMARY OF THE INVENTION In accordance with one aspect of the present invention, although not necessarily the broadest aspect, there is provided a lifting anchor for embedding in a concrete building component, said lifting anchor including a substantially planar anchor body, said anchor body being of an integral construction and including a first portion and a second portion, each for embedding in the concrete building component, said first portion including a transverse aperture therethrough adapted, in use, to co- operate with a clutch to allow for lifting of said building component, said second portion including a transverse aperture therethrough adapted to receive and releasably retain a reinforcement bar, said anchor further including at least one elongate member extending from said second portion and preferably offset from said first portion.

In accordance with another aspect of the present invention, although not necessarily the broadest aspect, there is provided a lifting anchor for embedding in a building component, preferably in the form of a pre­cast concrete panel, said lifting anchor including: an anchor body being of an integral construction and including a main body portion having a first transverse aperture extending therethrough; a secondary body portion having a second transverse aperture extending therethrough, said second aperture being off-set axially from said anchor body and said first aperture of said main body portion; and at least one elongate member extending from the free end of said secondary body portion and preferably off-set axially from said anchor body.

Suitably, said at least one elongate member includes a plurality of discontinuities or corrugations extending along at least part of the length dimension of at least one side or surface of said at least one elongate member, said discontinuities or corrugations being so sized and shaped as to allow said at least one leg member to co-operate with/be in engagement with one or more members or wire mesh whereby to prevent lateral movement of said anchor relative to said mesh.

Suitably, said discontinuities or corrugations extend along the entire length dimension of an upper side or surface of said at least one elongate member.

Suitably, said discontinuities or corrugations extend along the entire length dimension of respective and opposed upper and lower sides or surfaces of said at least one elongate member.

The at least one elongate member may include, at or in the vicinity of the free end remote from said anchor body, an enlarged end section.

The at least one elongate member may include one or more shaped protrusions extending substantially normally from at least one side or surface thereof, preferably the lower side or surface, such to assist in embedding of the lifting anchor in a concrete building component.

The lifting anchor may further include one or more lugs at or in the vicinity of said clutch engagement aperture and extending/protruding from at least one side or surface of said anchor body.

Suitably, said main body portion includes one or more opposed pairs of ears or lugs, one lug or ear of the or each pair disposed on each side of said clutch engagement aperture, the arrangement being such as to allow the clutch to bear against/be in contact with said lugs or ears, to provide resistance to shear loading during lifting of an associated building component.

The lifting anchor may include a reinforcing bar disposed through said off- set transverse aperture.

The reinforcing bar may be of a substantial U-shape.

The enlarged end section of said at least one elongate member may be in the form of an enlarged head member, formed integrally with said at least one elongate member or releasably attachable thereto.

The lifting anchor may be constructed from a material, preferably a metal or metal alloy, capable of withstanding a tensile load in excess of 7 .5 tonnes.

Suitably, said corrugations are of a saw-tooth profile, having a distance between adjacent peaks of no longer than 20 mm, and preferably of 15 mm.

The present invention seeks to overcome the problems and difficulties associated with prior art methods and apparatus by providing an improved lift anchor.

DESCRIPTION OF THE DRAWINGS In order that the invention may be more clearly understood and put into practical effect reference will now be made to preferred embodiments of a lift anchor in accordance with the present invention. The ensuing description is given by way of non­limitative example only and is with reference to the accompanying drawings, wherein: Fig. 1 is a perspective view, from above, of a preferred embodiment of a lift anchor in accordance with the present invention; Fig. 2 is a side elevational view of the embodiment of Fig. 3 is a view similar to showing the lift anchor associated with formwork and engaging with a wire of reinforcing mesh; Fig. 4 is a view, similar to FIGS. 2 and 3, with an additional tension bar in place; Fig. 5 is a perspective view, from above, of the arrangement of Fig. 6 is a perspective view, from above, of a further preferred embodiment of a lift anchor in accordance with the present invention; Fig. 7 is a top perspective view of yet another embodiment of a lift anchor in accordance with the invention; Fig. 8 is a top perspective view of another embodiment of a lift anchor in accordance with the invention; Fig. 9 is a view of a preferred embodiment of a lift anchor in accordance with the invention in engagement with a clutch, for purposes of lifting a pre-cast building component or the like; Fig. 10 is a perspective view of the lift anchor/clutch arrangement of Fig. 11 is a view, similar to of yet another embodiment of a lift anchor in accordance with the invention; Figs. 12 is a side elevational view of the embodiment of ; Fig. 13 is a side elevational view of the embodiment of FIGS. 11 and 12, with a tension bar in place; Fig. 14 is a top perspective view of the embodiment of ; Fig. 15 is a view, similar to , but with a tension bar of a different shape and configuration; Fig. 16 is a view, similar to of another embodiment of a lift anchor in accordance with the invention; and; Fig. 17 is a view of a variant of the embodiment of .

DESCRIPTION OF THE PREFERRED EMBODIMENTS A lift or lifting anchor in accordance with the present invention is of an integral construction (preferably) and includes, as principal components, a main body portion 1, a secondary body portion 2 extending therefrom and at least one leg member 3 projecting from said secondary body portion 2. In the embodiment of Figure 1 the main body portion 1 includes an exposed end, generally designated 4, having a central portion 5 and, at opposed ends thereof, projecting lugs 5a. The main body portion 1 includes, disposed substantially centrally thereof, a first transverse aperture 7 for purposes of clutch engagement and/or for passing therethrough a locking bolt or the like of a hoisting means or shackle (not shown). The secondary body portion 2 further includes, spaced apart from the first transverse aperture 7 and off-set therefrom as shown, a second transverse aperture 8 for a purpose to be described hereinafter in more detail. In the especially preferred embodiment shown the main body portion 1 includes opposed shear plates 6 intended to prevent, or minimise, movement of the overall anchor when in shear load (as for example during lifting).

Extending from the opposite end of the secondary portion 2 is the at least one leg member 3, which may be of any length and breadth, with the actual dimensions thereof not constituting part of the invention. In the especially preferred embodiments illustrated the leg member 3 will have corrugations 9 formed on both the upper and lower opposed surfaces thereof. In alternative embodiments, not shown, corrugations 9 may be provided only on the lower surface, or on three or all of such surfaces. As shown for example in the leg member 3 is off-set when considered relative to the first central aperture 7 and the main body portion 1.

Whilst the drawings shows corrugations 9 formed on top and bottom faces or sides of the leg member 3, it should be understood that in practice corrugations could be formed in or on any or all side or faces of that leg member 3. The corrugations 9 may be of any known shape and size, as for example round, saw-tooth or perhaps castellated. It should be understood that the shape, size, number and location of the corrugations do not form part of the invention. Whilst, in the preferred embodiment shown the corrugations 9 extend along substantially the entire length dimension of at least one surface or side of the leg member 3, in a further alternative such corrugations could extend only partly along that length dimension. In an especially preferred embodiment the corrugations 9 will be sized and shaped to co- operate with or suit standard mesh sizes, these days with either 100 mm or 200 mm spacing. The corrugations, having peaks spaced-part in an especially preferred embodiment by about 20 mm, function to enhance embedding of the anchor in the concrete, are shaped, sized and located relative to the mesh so as to restrict movement of the anchor to less than 20 mm in its longitudinal direction.

The secondary body portion 2, extending from the main body portion 1 and off-set therefrom as shown, is intended in use to be at least partially embedded in the concrete building component to serve as a first anchoring point. The second transverse aperture 8, in the secondary body portion 2, is adapted in use to releasably receive and retain, if desired, a reinforcement bar of any known type, size and shape.

A lifting anchor in accordance with the present invention is shown in use in, for example, FIGS. 3 to 5. With regard, by way of example only, to FIGS. 3 and 4, in accordance with known practices a lifting anchor is associated with formwork, generally designated 10, using what is referred to in the industry as a void former 11, which can be constructed from any suitable material, as for example a suitable steel or the like material, or perhaps of plastics material. The void former 11 may be secured to the formwork 10 in any known manner and using any known means, as for example a setting bolt. The lifting anchor is then inserted into the void former 11 and can then be secured thereto in any known manner (as for example by the interposition of a rubber ring).

It should be understood that there exist a number of different types of void formers, and that the type actually used is not of the essence of the invention.

Preferably, in one embodiment an articulated void former may be utilized.

It is a common practice in the industry, in the formation of pre-cast concrete building components, to use one or more layers of reinforcing wire mesh, made up of an array of longitudinal and transverse wires 20, 21. The corrugations 9 engage with one or more cross members of the reinforcing wire mesh. As shown in, for example, in use the leg member 3 will overlay one or more transverse wires 21 of the reinforcing mesh, with the or each transverse wire 21 to be in engagement with or cooperation with a corrugation 9 of the surface of the leg member 3. By virtue of the fact that the leg member 3 is off-set relative to the main body portion 1, of the lifting anchor, the lifting anchor in accordance with the invention will be centrally located on the wire mesh, in turn allowing for the clutch engagement hole or aperture 7 to be substantially centrally located relative to a building panel.

As shown in FIGS. 4 and 5, a lifting anchor in accordance with the present invention can also have associated therewith, disposed through aperture 8, a reinforcing bar 30 of any suitable shape. The drawings show a number of preferred embodiments for such a reinforcing bar 30. As shown the reinforcing bar 30 can be in engagement with, or overlay, one or more of either the transverse and/or longitudinal wires 21, 20 of a layer of reinforcing wire mesh. The fact that the aperture 8, for receiving the reinforcing bar 30, is off-set from the clutch-engagement aperture 7 ensures that the reinforcing bar 30 will sit flat on the substantially centrally located wire mesh, with the clutch engagement aperture 8, as stated, substantially centrally located in or on a panel.

FIGS. 4 and 5 show one possibility, wherein the reinforcing bar 30 is of a substantial U-shape. In practical terms, however, the reinforcing bar 30 can be of any shape, as for example of a sinusoidal shape of or a U-shape, with or without corrugations, with a foot provided at each free end thereof. The foot affords an enlarged surface area to enhance bonding with the concrete during formation of a building component or panel. shows an alternative embodiment for a lifting anchor in accordance with the invention. Therein the upper and lower surfaces of the leg member 3 need not have corrugations formed thereon, and at the free end of the leg member 3 there is provided a shaped foot 40, again intended to enhance embedding of the anchor in the cement/concrete building component or panel.

Turning then to and 8, such show alternative embodiments for a lifting anchor in accordance with the invention. In such embodiments the leg member 3 may or may not include corrugations extruding along at least part of the length dimension of any one or more surfaces thereof. However, such leg member 3 may have one or more shaped protrusions, designated as 12 and 13 respectively, extending substantially normally to at least one surface, preferably the lower surface, thereof. These extensions 12 and 13 afford the leg member an enlarged surface area, whereby to enhance embedding of the overall anchor in the concrete panel.

FIGS. 9 and 10 show view of a clutch, shackle or the like 50 which is adapted, in use, to co-operate with a lifting anchor in accordance with the present invention. It must be understood, however, that the actual type, shape and/or configuration of the clutch hook or shackle 50 is not of the essence of the invention.

Indeed any known clutch, shackle or hook, as now in use, will be equally suitable.

With particular reference to, for example, and FIGS. 9 and 10 the shaped, exposed end 4, 5 of the anchor, with its shaped lugs 5a, serves a practical purpose. The lugs, in use, prevent movement of the anchor relative to the clutch, shackle or hook 50 when in shear load.

Turning then to FIGS. 11 to 15, such show yet another embodiment of a lift anchor in accordance with the invention. As shown in , for example, the lift anchor 100 is adapted, in use, to be associated with form work 10, as with earlier embodiments, using a void former 11 of any known type. In this embodiment the lift anchor 100 includes a single leg member 101, with corrugations 102 extending along at least part of the lower surface thereof. The leg member 101 terminates in a shaped foot 103, again for the purpose of enhancing bonding with concrete during formation of a building component or panel. The lift anchor 100, in like manner to the earlier- described embodiments, includes an aperture 104 adapted to receive and co-operate with a tension bar 30 of any known type. In like manner to the embodiment of the main body portion 105 of lift anchor 100 includes a transverse aperture 106.

In the embodiment shown in the tension bar 30 is, as shown, not straight along its entire length. shows yet another embodiment of a lift anchor. With this embodiment, in contrast to what it shown in the lift anchor includes a shear plate 6 on only one side thereof, with that shear plate 6 including an up-turned end 6a. then shows a variant of the lift anchor of , with a single shear plate 6 having a down-turned end section 6b.

Preferably the corrugations 9 are sized and shaped that the distance between adjacent peaks is less than 15 mm. Since one or more of the corrugations 9 interact with or overlay with one or more transverse wires of the wire mesh, then such limits the amount of movement possible.

In an especially preferred embodiment the lift anchor in accordance with the present invention will be constructed of a material, preferably a metal or metal alloy, which exhibits a tensile strength sufficient to support a tensile load of at least 7.5 tonnes. It should be understood, however, that neither the material of construction nor the actual method of construction form part of the invention. Preferably, however, the anchor may be formed by forging. The elongate member has a profile which creates a mechanical connection with the surrounding concrete. The profile exhibits corrugations, saw-tooth or, in fact, any other known shape.

The anchor preferably includes, at least one end/side thereof, an enlarged ear or leg, intended to restrict any load which is applied to the overall anchor, by the clutch or the like when a shear load is applied.

Finally, it is to be understood that the aforegoing description refers merely to preferred embodiments of the invention, and that variations and modifications will be possible thereto without departing from the spirit and scope of the invention, the ambit of which is to be determined form the following claims.

Claims (15)

1. A lifting anchor for embedding in a concrete building component, said lifting anchor including a substantially planar anchor body, said anchor body being of an integral construction and including a first portion and a second portion, each for embedding in the concrete building component, said first portion including a transverse aperture therethrough adapted, in use, to co-operate with a clutch to allow for lifting of said building component, said second portion including a transverse aperture therethrough adapted to receive and releasably retain a reinforcement bar, said anchor further including at least one elongate member extending from said second portion and preferably offset from said first portion.

2. A lifting anchor for embedding in a building component, preferably in the form of a pre-cast concrete panel, said lifting anchor including: an anchor body being of an integral construction and including a main body portion having a first transverse aperture extending therethrough and a secondary body portion having a second transverse aperture extending therethrough, said second aperture being off-set axially from said first aperture of said anchor body and said main body portion, and at least one elongate member extending from the free end of said secondary body portion and preferably off-set axially from said anchor body.

3. The lifting anchor as claimed in Claim 1 or Claim 2, wherein said at least one elongate member includes a plurality of discontinuities or corrugations extending along at least part of the length dimension of at least one side or surface of said at least one elongate member, said discontinuities or corrugations being so sized and shaped as to allow said at least one leg member to co-operate with/be in engagement with one or more members or wire mesh whereby to prevent lateral movement of said anchor relative to said mesh.

4. The lifting anchor as claimed in Claim 3, wherein said discontinuities or corrugations extend along the entire length dimension of an upper side or surface of said at least one elongate member.

5. The lifting member as claimed in Claim 3, wherein said discontinuities or corrugations extend along the entire length dimension of respective and opposed upper and lower sides or surfaces of said at least one elongate member.

6. The lifting anchor as claimed in any one of the preceding claims, wherein said at least one elongate member includes, at or in the vicinity of the free end remote from said anchor body, an enlarged end section.

7. The lifting anchor as claimed in any one of the preceding claims, wherein said at least one elongate member includes one or more shaped protrusions extending substantially normally from at least one side or surface thereof, preferably the lower side or surface, such to assist in embedding of the lifting anchor in a concrete building component.

8. The lifting anchor as claimed in Claim 7, further including one or more lugs at or in the vicinity of said clutch engagement aperture and extending/protruding from at least one side or surface of said anchor body.

9. The lifting anchor as claimed in any one of the preceding claims, wherein said main body portion includes one or more opposed pairs of ears or lugs, one lug or ear of the or each pair disposed on each side of said clutch engagement aperture, the arrangement being such as to allow the clutch to bear against/be in contact with said lugs or ears, to provide resistance to shear loading during lifting of an associated building component.

10. The lifting anchor as claimed in any one of the preceding claims, including a reinforcing bar disposed through said off-set transverse aperture.

11. The lifting anchor as claimed in Claim 10, wherein said reinforcing bar is of a substantial U-shape.

12. The lifting anchor as claimed in any one of Claims 6 to 11, wherein said enlarged end section of said at least one elongate member is in the form of an enlarged head member, formed integrally with said at least one elongate member or releasably attachable thereto.

13. The lifting anchor as claimed in any one of the preceding claims, constructed from a material, preferably a metal or metal alloy, capable of withstanding a tensile load in excess of 7 .5 tonnes.

14. The lifting anchor as claimed in any one of the preceding claims, wherein said corrugations are of a saw-tooth profile, having a distance between adjacent peaks of no longer than 20 mm.

15. The lifting anchor as claimed in claim 14, wherein said distance is 15 mm.