AU2021205114A1

AU2021205114A1 - Attachment for positioning cast-in concrete anchors

Info

Publication number: AU2021205114A1
Application number: AU2021205114A
Authority: AU
Inventors: Hayden Jurey
Original assignee: Threadlegs Pty Ltd
Current assignee: Threadlegs Pty Ltd
Priority date: 2021-07-16
Filing date: 2021-07-16
Publication date: 2023-02-02
Also published as: AU2023100047A4; AU2023100047B4

Abstract

P10603.AU Specification final - 16/07/2021 ABSTRACT An attachment for positioning a cast-in concrete anchor relative to concrete formwork prior to pouring of concrete therein, comprising: 5 an upper body having a threaded opening for securing to a lower end of the anchor;and a base associated with the body and configured for, in use, placement against and securement to formwork so as to fix a position of the anchor relative thereto. 4/7 32 26 22 24 36b 20 26 34 30 36a 36a 32 36b 28 18 Figure 4

Description

4/7

24 32 26 22 36b 20 26

34

30

36a 36a 32 36b 28

18

Figure 4

P10603.AU Specification final - 16/07/2021

Attachment for positioning cast-in concrete anchors

Field of the invention The present patent specification relates to an attachment for positioning cast-in concrete anchors such as hold down bolts (also known via other terms, such as cast-in threaded rods and rag bolts). In an embodiment, the attachment is securable to a base of cast-in threaded rods, and is securable to concrete formwork to fix a position of the rod prior to the pouring of concrete into the formwork.

Background Figure 1 shows threaded concrete anchors 2 cast in a concrete base 4. The anchors enable a steel column 6 to be secured to the concrete base. Before casting the concrete base 4, each anchor 2 ought to be precisely positioned relative to associated concrete formwork and/or reinforcement such that, after the concrete 4 cures, the anchors 2 protrude out from the concrete 4 at locations that enable the anchors 2 to pass through openings formed in a base of the steel column 6. In essence, it is important to ensure accurate positioning of cast-in concrete anchors 2 before and during pouring of concrete so that the anchors 2 are not displaced from their intended positions. Otherwise, the anchors 2 may not be adequately positioned to secure the intended structures.

Figure 2 shows four threaded anchors 2 positioned relative to concrete formwork 8 and reinforcement 10. The lower end of each anchor 2 is provided with a steel plate 12 sandwiched between an upper nut 14 and a lower nut (not shown). The tip of the lower end of each anchor 2 (not shown) typically extends beyond the lower nut and is exposed to the open air. In positioning each anchor 2, the lower ends of each anchor 2 are suspended above the formwork 8 so that when the concrete slab is poured, the lower end of the anchors 2 are covered by and completely encased in the concrete slab. This ensures the lower ends of the anchors 2 are protected in the concrete slab and not exposed to the elements, whereby corrosion can occur to anchors and connecting reinforcement within the slab.

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However, the need to keep the anchors 2 suspended above the formwork 8 makes it difficult to fix the position of each anchor 2 relative to the surrounding reinforcement 10 and/or formwork 8. As such, during construction and installation of the concrete reinforcement 10, formwork 8, associated plumbing, wiring and the like, and also during pouring of concrete, the anchors 2 may be displaced from their intended positions. Figure 2 shows cable ties 16 being used in an attempt to secure the anchor rods 2 to adjacent reinforcement 10. Of course, cable ties 16 are relatively weak and are prone to breakage or movement.

Figure 3 shows what can occur when the anchors 2 are displaced from their intended positions. In this Figure, the four hold down bolts 2' have shifted relative to their intended locations, and as such, one or more of the bolts 2'cannot be received in a corresponding preformed hole in a base of the steel column 6. Instead, structural modifications have been made to the base of the steel column 6 to allow it to be secured via the displaced anchors 2'. It is thus important to ensure the precise positioning of concrete anchors 2 before, during and after the pouring of concrete, so that they are not displaced from their intended positions. Displaced anchors 2' may result in compromised structures that require additional resources, engineering and labour to address, and can pose safety risks.

There is a need to address the above, and/or at least provide a useful alternative.

Summary According to a first aspect of the present invention, there is provided an attachment for positioning a cast-in concrete anchor relative to concrete formwork prior to pouring of concrete therein, comprising: an upper body having a threaded opening for securing to a lower end of the anchor;and

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a base associated with the body and configured for, in use, placement against and securement to formwork so as to fix a position of the anchor relative thereto.

According to embodiments of the invention, the base comprises one or more features configured for alignment with respective indicators provided on the formwork.

According to embodiments of the invention, the features comprise respective indentations formed in the base. The features may assist with alignment of the anchors with markings premarked on the formwork indicating intended anchor installation positions.

According to embodiments of the invention, the attachment further comprises legs extending downwardly from the body, wherein the base is generally ring-shaped and associated with lower ends of the respective legs such that the legs maintain the body at a height above that of the base.

According to embodiments of the invention, the base comprises one or more openings through which fasteners can be driven to secure the attachment to formwork.

According to embodiments of the invention, the openings are disposed at respective quadrants of the base.

According to embodiments of the invention, each feature of the base is associated with a respective opening.

According to embodiments of the invention, the base comprises a wall extending upwardly from an outer perimeter of the base.

According to embodiments of the invention, the wall comprises the one or more features.

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According to embodiments of the invention, the features are symmetrically disposed about an outer perimeter of the base.

According to a second aspect of the present invention, there is provided a method of securing a cast-in concrete anchor relative to concrete formwork prior to pouring of concrete therein, comprising: securing the attachment according to a first aspect of the present invention to a lower end of the anchor; and fixing the attachment to concrete formwork such that the anchor is spaced from the formwork.

According to embodiments of the invention, the method further comprises: prior to fixing the attachment, marking the formwork to indicate a position that the attachment and/or associated anchor is to be secured; and aligning features of the attachment with the marking.

According to a third aspect of the present invention, there is provided a method of supporting a setdown above concrete reinforcement prior to pouring of concrete, comprising: securing the attachment of any one of claims 1 to 10 to a lower end of a threaded anchor provided with a height adjustment means; securing an upper end of the anchor to the setdown such that it rests on the height adjustment means; and adjusting the height adjustment means such that the attachment is positioned on a base underlying the concrete reinforcement and the setdown is positioned at a desired height above the reinforcement.

According to embodiments of the invention, the height adjustment means comprises a nut that is rotatable along the threaded anchor to effect height adjustment of the setdown.

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Brief description of the drawings An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a front view of a steel column fixed to a concrete base via threaded anchors cast in the concrete base; Figure 2 is a top perspective view of four threaded anchors positioned relative to concrete reinforcement, lower ends of each anchor being suspended above concrete formwork; Figure 3 is a side perspective view of a steel column secured to a concrete base via concrete anchors, all of which are displaced from their intended positions; Figure 4 is a front perspective view of an attachment according to embodiments of the present invention; Figure 5 is a top view of the attachment of Figure 4; Figure 6 shows how the present attachment can be used to support and adjust a height of setdowns relative to concrete reinforcement; and Figure 7 shows how the present attachment can be used to support and adjust a height of a plate relative to concrete reinforcement.

Detailed description Figures 4 and 5 show an embodiment of the present attachment 18. The attachment 18 is configured to attach to a lower end of a threaded anchor 2. The attachment 18 can then be fixed, for example, to adjacent formwork, thereby fixing a position of the anchor 2 relative to the concrete formwork.

Referring to Figure 4, in one embodiment, the attachment 18 may be integrally formed from a material that is not vulnerable to corrosion, such as plastic. The attachment 18 comprises a generally cylindrical, upper body portion 20, having a centrally disposed threaded through hole 22. The threaded hole 22 allows the attachment 18 to screw onto a lower end of a threaded anchor 2. Of course, the attachment 18 may be

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formed in different sizes, with different thread configurations and the like to suit the anchor 2 to which it is to be secured. Advantageously, before securing the attachment 18 to adjacent formwork, the attachment 18 can be screwed up and down the threaded anchor 2 to adjust a vertical position thereof. This adjustment process can help to vertically level a group of anchors 2.

An upper surface 24 of the body 20 is generally flat, thereby allowing the upper surface 24 to be positioned relatively flush against other attachments, such as steel plates 12 and spacers (see Figure 2) and the like.

Extending downwardly from an exterior of the upper body 20 are four, generally vertical legs 26 with a ribbed configuration. The legs 26 are preferably equispaced around a circumference of the upper body 20. The height and angle of the legs 26, among other parameters, may of course be varied to suit the specific application.

The attachment 18 also comprises a base 28 via which the attachment 18 can be fixed to adjacent formwork. In the Figures, the base 28 is generally ring-shaped and extends around and from a base or lower end of each of the four legs 26. The base 28 defines an annular platform that can be placed against and secured to formwork. The legs 26 extend upwardly from the base 28 and maintain the upper body portion 20 at a height above a height of the base 28.

The base 28 comprises a generally planar ring-shaped surface 30, wherein quadrants thereof are provided with respective holes 32 through which fasteners can be driven to secure the attachment 18 to adjacent formwork. In the Figures, the base 28 comprises bulges proximate each through hole 32 so that the planar surface 30 of the base 28 provides sufficient surface area to receive, for example, a head of the fastener (e.g., the head of a screw or nail).

A continuous wall 34 extends upwardly from an outer perimeter of the base 28. The wall 34 is provided with features 36 which can be aligned with indicators on the

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formwork to help position the attachment 18, and thus the associated anchor 2, at its intended position.

In Figure 4, the features are depicted as vertically extending indentations or grooves 36 formed in the upwardly extending wall 34 of the base 28. In particular, the grooves 36 are disposed symmetrically about the wall 34. In the Figures, a groove 36a is positioned proximate a respective through hole 32. Additional grooves 36b in the wall 34 are formed at positions generally equidistant between adjacent through holes 32. As such, the four grooves 36a align with one another to define an imaginary cross. Similarly, the four grooves 36b align with one another to define a second imaginary cross, offset from the first-mentioned cross by about 45 degrees.

In use, a surveyor or the like may mark, e.g. with a pencil, a cross on the formwork indicating where each attachment 18 and thus anchor 2 is to be positioned. The grooves 36a, 36b of the attachment 18 may thus be easily visually aligned with the marked cross, and thereafter secured to the formwork at the intended position.

The present attachment 18 allows the position of a respective anchor 2 to be fixed relative to concrete formwork and/or reinforcement, while still allowing the lower end of the anchor 2 to be held above the formwork upon which the concrete will be poured. As such, after the concrete is poured, the lower end of the anchor 2 will still be encased in the concrete slab and thus remains protected from the elements. The base 28 of the plastic attachment 18 may be exposed to the elements but is advantageously not vulnerable to corrosion. It will be noted that the depicted attachment 18 is generally open (e.g., the legs 26 are spaced from one another and the base 28 is ring-shaped as opposed to being a closed or solid circular shape) to allow concrete and aggregate to flow within and around the attachment 18 while minimising the formation of air pockets and cavities in the resulting concrete structure.

Many modifications of the above embodiments will be apparent to those skilled in the art without departing from the scope of the present invention. For example, while the

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attachment 18 has been described in relation to concrete formwork, the attachment 18 may of course also be used where a sand or earth-based subgrade is used as a base for footings, foundations and ground slabs.

While the attachment 18 has been described in relation to fixing a position of suspended concrete anchors 2, the attachment may be used in other applications. One such application is illustrated in Figure 6. Figure 6 shows timber setdown 38 suspended above reinforcement 10. The setdown 38 is commonly suspended via conventional bar chairs 40. However, bar chairs 40 are not height adjustable, and so methods for suspending the setdown 38 at different heights is often improvised. For example, in Figure 6, the frontmost setdown is suspended via a cut piece of PVC piping 42.

The present attachment 18 can be utilised to suspend setdown 38 at the desired height. In this regard, a threaded rod 2 and nut 14 can be secured to the setdown 38 for support thereof. An attachment 18 can be secured to a base of the rod 2. The nut 14 can be screwed up and down the rod 2 to adjust a height at which the setdown 38 is installed.

Figure 7 shows another application in which the present attachment 18 may be utilised. In this case, a steel column 6 is to be mounted on a steel plate 44 suspended above concrete reinforcement 10. In instances where legs 2b of the steel plate 44 are threaded, the attachments 18 can be secured to a lower ends of the legs and be rotated thereabout to allow for vertical adjustment of the plate 44.

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.

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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.

Claims

P10603.AU Specification final - 16/07/2021 - 10 CLAIMS:

1. An attachment for positioning a cast-in concrete anchor relative to concrete formwork prior to pouring of concrete therein, comprising: an upper body having a threaded opening for securing to a lower end of the anchor;and a base associated with the body and configured for, in use, placement against and securement to formwork so as to fix a position of the anchor relative thereto.

2. An attachment of claim 1, wherein the base comprises one or more features configured for alignment with respective indicators provided on the formwork.

3. The attachment of claim 2, wherein the features comprise respective indentations formed in the base.

4. The attachment of any one of the preceding claims, further comprising legs extending downwardly from the body, wherein the base is generally ring-shaped and associated with lower ends of the respective legs such that the legs maintain the body at a height above that of the base.

5. The attachment of any one of the preceding claims, wherein the base comprises one or more openings through which fasteners can be driven to secure the attachment to formwork.

6. The attachment of claim 5, wherein the openings are disposed at respective quadrants of the base.

7. The attachment of claim 5 or 6 as appended to either of claim 2 or 3, wherein each feature of the base is associated with a respective opening.

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8. The attachment of any one of the preceding claims, wherein the base comprises a wall extending upwardly from an outer perimeter of the base.

9. The attachment of claim 8 as appended to claim 2 or 3, wherein the wall comprises the one or more features.

10. The attachment of claim 2 or 3, wherein the features are symmetrically disposed about an outer perimeter of the base.

11. A method of securing a cast-in concrete anchor relative to concrete formwork prior to pouring of concrete therein, comprising: securing the attachment of any one of the preceding claims to a lower end of the anchor;and fixing the attachment to concrete formwork such that the anchor is spaced from the formwork.

12. The method of claim 11, further comprising: prior to fixing the attachment, marking the formwork to indicate a position that the attachment and/or associated anchor is to be secured; and aligning features of the attachment with the marking.

13. A method of supporting a setdown above concrete reinforcement prior to pouring of concrete, comprising: securing the attachment of any one of claims 1 to 10 to a lower end of a threaded anchor provided with a height adjustment means; securing an upper end of the anchor to the setdown such that it rests on the height adjustment means; and adjusting the height adjustment means such that the attachment is positioned on a base underlying the concrete reinforcement and the setdown is positioned at a desired height above the reinforcement.

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14. The method of claim 13, wherein the height adjustment means comprises a nut that is rotatable along the threaded anchor to effect height adjustment of the setdown.