WO2008006176A1

WO2008006176A1 - Anchor for casting into concrete

Info

Publication number: WO2008006176A1
Application number: PCT/AU2007/000984
Authority: WO
Inventors: Bruce Ian Ireland
Original assignee: Danley Construction Products Pty Ltd
Current assignee: Danley Construction Products Pty Ltd
Priority date: 2006-07-14
Filing date: 2007-07-16
Publication date: 2008-01-17
Anticipated expiration: 2009-01-14
Also published as: NZ573012A; AU2007272244B2

Abstract

An anchor assembly (10) comprises an anchor housing in the form of an integral nut body (11), a positioning means in the form of a locating plate (12), a passage means in the form of a tube (13), a tube coupling (14) and an end cap (15) to close the end of the tube.

Description

ANCHOR FOR CASTING INTO CONCRETE

FIELD OF THE INVENTION

THIS INVENTION relates to an anchor for casting into concrete and in particular but not limited to an assembly of lost formwork for provision of a nut and accompanying tubular form which may be secured in position and used as lost form work to enable a bar to be positioned in the concrete and screwed into the threaded nut after the concrete has cured.

BACKGROUND TO THE INVENTION

Anchors are commonplace in all sorts of environments where it is later required to fit a counterpart to the anchor. One such situation is the case of an in-situ anchor positioned in a cavity that is set to receive a material which is laid while wet and allowed to harden around the anchor but where lost form-work protects the anchor against ingress of the wet material. Once the material has hardened the position of the anchor is set and due to the protection arrangement the counterpart may be passed through a passage to engage the anchor. If the anchor has been wrongly positioned then the hardened material may have to be pulled up and the anchor repositioned or some alternative pursued at the site.

It is therefore critical that the anchor remain in the desired position. While there are many forms of anchors the present invention relates to discrete anchors which rely on the pull out capacity of the anchor in relation to its immediate vicinity.

The International Type Search in respect of the Australian Provisional Patent Application No. 2006903808 from which the present application claims priority, revealed six prior patent documents that the search examiner considered relevant to the search statement filed with the search request. These documents are listed as follows GB 2036231 (BRIDGESTONE); EP 121510 (MEYERS CLAUDE); GB 2060806 (SANYO INDUSTRIES); US 3405497 (McNAIR); US 5937609 (ROTH); and US 5205690 (ROTH). GB 2036231 (BRIDGESTONE) describes face mounted anchor including and anchor box housing a nut type anchor as lost formwork for a marine quay. The anchor includes a mounting flange with an entry for a bolt at the same end as and co-axial with the mounting flange and hence is face mounted. A tube extends from the mounting flange to a nut at the other end of the tube. The nut is inside a tapered enlargement with a nut shaped hole forming an anti-rotation housing for the nut. A cap is screwed onto the enlargement to close the end. This arrangement has a number of disadvantages due to its application to a marine quay that make it unsuitable for other applications. In the marine quay situation the tube is mounted horizontally and consequently as concrete is being poured the box is prone to move and wet concrete may creep into the tube. To deal with this the tube is made integral with the flange, the flange having depressions so that concrete enters the depressions and solidifies before entering the tube proper. As a result of the design there is not capacity for easy adjustment to suit different thicknesses of concrete as might be required with flooring. In addition pull-out capacity is determined by the tapered surface of the housing thus displacing load outwardly and diverging. The bolt must pass all the way through the nut to ensure proper connection. Again the arrangement does not cater for general application but is specific to the marine quay environment. EP 121510 (MEYERS CLAUDE) relates to anchors of the type that rely upon the strength of the reinforcing bars and the concrete beyond the immediate vicinity of the anchor. These are typical of continuity systems for joining two reinforcing bars. This type of anchor is not relevant to the present invention but has been included for the purpose of comparison.

GB 2060806 (SANYO INDUSTRIES) describes another face mounted anchor with the entry at the same end as the mounting flange. These is no easy way to cater for different thicknesses of concrete. The pull out capacity is derived from a cone surface thus displacing load outwardly and diverging. US 3405497 (McNAIR) describes another face mounted anchor with the entry at the same end as the mounting flange. Pull-out capacity is derived from a separate bolt projecting into the concrete in a ceiling. As for the

BRIDGESTONE anchor this anchor may have application to ceilings for suspension fitting of generally lightweight character but it has little if any application elsewhere.

US 5937609 (ROTH) describes another face mounted arrangement. In this case a U-shaped section of flat bar with a bridging internally threaded collar is embedded in the concrete and a threaded bar may be installed after the concrete has hardened. The pull out capacity is derived from the inner arm of the U-shaped bar which is offset so that there is uneven load distribution around the immediate vicinity of the anchor.

US 5205690 (ROTH) is similar to the McNAIR anchor and similar comment applies to this anchor. In view of the above prior art anchors, the present invention offers an alternative anchor which differs significantly and provides the public with a useful alternative.

OUTLINE OF THE INVENTION In one aspect the present invention resides in an anchor assembly comprising an anchor, an anchor housing, the anchor being located inside the anchor housing, a formwork attachment means and a passage means extending from the anchor housing, the passage means having one end adjacent the anchor housing and another end remote from the anchor housing, the remote end having an entry for a counterpart to the anchor so that the counterpart may pass along the passage and engage the anchor, the formwork attachment means being at or adjacent the end of the assembly the entry to the passage means.

Preferably, the anchor comprises a nut formed integrally with the housing. Preferably the anchor assembly comprises nut positioning means formed separately or integrally with the nut and having form work attachment means in the form of screws passing through the positioning means and able to be secured to form work to locate the nut and housing in place. Preferably, the positioning means comprises a plate suspended a predetermined distance from the formwork. The size of the plate determines the pull out capacity of the anchor assembly.

Preferably, the housing includes a base which abuts the formwork and the positioning means surrounds the housing in operative coupling thereto so it is spaced from the base of the housing so as to also be spaced from the formwork. Preferably the assembly further comprises passage means in the form of a tube alignable with the threaded portion of the nut providing bolt passage means or bar passage means through a poured slab for entry of a bar through the passage means and in alignment with and screwable into the nut. The housing is typically a T-shaped body having a central threaded up stand of square section forming the nut and projecting from the base, the base extending outward on opposite sides to form opposite arms, each arm having a locating projection and the positioning means having a main aperture being slidable over and along the central up stand and having locating apertures which seat over the projections, the positioning means having holes for passage of fasteners through the positioning means and into the formwork.

Preferably, the passage means is formed from a tube and tube coupling, the tube coupling having one end that fits over the housing and another end that fits over the outside of the tube to couple the tube to the housing. The remote end of the tube is typically closed using a removable plug.

It will be appreciated that tubes are interchageable to alter the length of the passage for different thicknesses of concrete. To this end it is preferable that the tube be connected to the housing via a tubular coupling.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the present invention may be more readily understood and be put into practical effect, reference will now be made to the accompanying drawings which illustrate one preferred embodiment of the invention and wherein:-

Figure 1 illustrates an assembly according to the present invention; Figure 2 illustrates the parts of the assembly of Figure 1 ; Figure 3 shows two of the assemblies of Figure 1 in position in-situ; and Figure 4 illustrates an alternative application of the present invention.

METHOD OF PERFORMANCE Referring to the drawings and initially to Figure 1 (assembled anchor assembly) and Figure 2 (the unassembled parts) there is illustrated an anchor assembly 10 comprising an anchor housing in the form of an integral nut body 11 , a positioning means in the form of a locating plate 12, a passage means in the form of a tube 13, a tube coupling 14 and an end cap 15 to close the end of the tube (not shown in Fig.1 ).

The nut body is generally T-shaped having a central spigot 16 which is of square section and has an internal threaded passage 17 running along its entire length, thus there is no requirement for the incoming threaded bar to exit the end for the required engagement as for a standard nut since it is made more than long enough. The nut body has a base 18 extending to opposite side arms 19 and 20, the arms 19 and 20 having location projections 21 and 22.

The coupling 14 has a collar 23 which has an internal bore matched to the spigot to fit as shown in Figure 1. It has a second collar 24 to fit the tube 13.

The base of the nut body has a circular position flange for initial location of the base against formwork, it may be tapped into position or located in a pre- drilled hole. The plate 12 has a central square hole 25 so that it fits over the spigot 16 and two location holes 26 and 27 so that it fits over the projections 21 and 22. There are four holes 28,29,30 and 31 for nails or screws to secure the plate 12 to the formwork in the position shown in Figure 1. Thus the base is secured. The coupling and a tube of the required depth may then be placed in position and the tube capped.

Figure 3 shows assemblies 10 nailed or screwed down to a timber form 32 prior to concrete being poured into the box as shown. Figure 4 shows assemblies 10 in inverted position as an alternative using batons 24.

In each case the caps of the tubes are accessible so that they may be removed after the concrete has hardened and a threaded bar passed through the tube from the side opposite the mounting to the formwork or baton. Whilst the above has been given by way of illustrative example of the present invention many variations and modifications thereto will be apparent to those skilled in the art without departing from the broad ambit and scope of the invention as set out in the appended claims.

Claims

1. An anchor assembly comprising an anchor, an anchor housing, the anchor being located inside the anchor housing, a formwork attachment means and a passage means extending from the anchor housing, the passage means having one end adjacent the anchor housing and another end remote from the anchor housing, the remote end having an entry for a counterpart to the anchor so that the counterpart may pass along the passage and engage the anchor, the formwork attachment means being at or adjacent the end of the assembly the entry to the passage means.

2. An anchor assembly according to claim 1 wherein the anchor comprises a nut formed integrally with the housing.

3. An anchor assembly according to claim 1 wherein the anchor comprises a nut formed integrally with the housing and the anchor assembly includes nut positioning means formed separately or integrally with the nut and having form work attachment means in the form of screws passing through the positioning means and able to be secured to form work to locate the nut and housing in place.

4. An anchor assembly according to claim 1 wherein the anchor comprises a nut formed integrally with the housing and the anchor assembly includes nut positioning means formed separately or integrally with the nut and having form work attachment means in the form of screws passing through the positioning means and able to be secured to form work to locate the nut and housing in place, the positioning means comprising a plate suspended a predetermined distance from the formwork.

5. An anchor assembly according to claim 1 wherein the housing includes a base which abuts the formwork and the positioning means surrounds the housing in operative coupling thereto so it is spaced from the base of the housing so as to also be spaced from the formwork.

6. An anchor assembly according to claim 1 wherein the anchor comprises a threaded nut and the assembly further comprises passage means in the form of a tube alignable with the threaded portion of the nut providing bolt passage means or bar passage means through a poured slab for entry of a bar through the passage means and in alignment with and screwable into the nut.

7. An anchor assembly according to claim 1 wherein the housing is a T- shaped body having a central threaded up stand of square section forming the nut and projecting from the base, the base extending outward on opposite sides to form opposite arms, each arm having a locating projection and the positioning means having a main aperture being slidable over and along the central up stand and having locating apertures which seat over the projections, the positioning means having holes for passage of fasteners through the positioning means and into the formwork.

8. An anchor assembly according to claim 1 wherein the passage means is formed from a tube and tube coupling, the tube coupling having one end that fits over the housing and another end that fits over the outside of the tube to couple the tube to the housing.