AU2007231910B2 - Spacer - Google Patents

Abstract

P\OPER\RSHI3I07414-CAP doc-9/11 l2(X17 -5 A spacer for concrete reinforcement, the spacer comprising a central post having at its upper end a seat for the reinforcement, and a substantially flat base with a central aperture, 5 the lower end of the central post being joined to the base by a pair of divergent beams extending to opposite sides of the aperture, the spacer being integrally formed as a one piece moulding. ,2

Description

Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT (ORIGINAL) Name of Applicant: ITW Construction Products Australia Pty Ltd Actual Inventor: Andrew Emden O'Loughlin Address for Service: DAVIES COLLISON CAVE, Patent Attorneys, 1 Nicholson Street, Melbourne, Victoria 3000. Invention Title: "Spacer" Details of Associated Provisional Application No.: 2007900918 22 February 2007 The following statement is a full description of this invention, including the best method of performing it known to us: Q:\OPER\RSH\July 07 - Dec 07\30407841-CAP-312 doc - /11 /07 P\0PER\RSH\3O40784 -CAP doc-/ I I /2W07 SPACER The present invention relates to a spacer or bar chair for reinforcing bar or grid and particularly for use with so-called "slab on ground" casting. 5 According to the present invention, there is provided a spacer for concrete reinforcement, the spacer comprising a central post having at its upper end a seat for the reinforcement, and a substantially flat base with a central aperture, the lower end of the central post being joined to the base by a pair of divergent beams extending to opposite sides of the aperture, 10 the spacer being integrally formed as a one-piece moulding. In a preferred embodiment the central post is of cruciform cross-section and the two beams extend from opposite limbs of the post in the same plane as those limbs. A central reinforcing web extends downwardly from the lower end of the post between the beams 15 and is connected to the base at opposite sides of the aperture, the web being coplanar with the other two limbs of the central post. An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which: 20 Figure 1 is a side view of a spacer in accordance with an embodiment of the invention; Figure 2 is a side view at right angles to that of Figure 1; Figure 3 is a perspective view; Figure 4 is an underneath view; and 25 Figure 5 is a side view equivalent to Figure 1 but showing an alternative form of clip associated with a seat of the spacer. As shown in the accompanying drawings the spacer or bar chair for reinforcing bar or reinforcing grid for use in "slab on ground" casting, comprises a central post 2 of cruciform 30 cross-section. At its upper end, the central post carries a seat 4 for a reinforcing bar B or a bar of a reinforcing grid. Resilient lugs 6 extend from opposite edges of the seat 4 at its P\PER\RSHU0407841-CAPdoc-8/I If0)7 -2 upper end and form a clip for retaining the spacer to the bar. The bar is engaged into the seat by passage between the two lugs 6 which are spaced by a distance less than the diameter of the bar whereby passage of the bar causes the lugs to deflect and then to snap back over the bar. 5 The spacer has a substantially flat base 8 with a central aperture 10. This form of base is particularly suitable for use when casting onto soft or uneven ground and provides better stability for the spacer on such a surface than would a base in the form of a solid disk. It is to be understood, however, that the base is also suitable for use when casting onto a flat 10 slab. At its lower end portion the central post 2 is connected to the base 8 at opposite sides of the aperture 10 by a pair of divergent beams 12 which provide the principal support for the post from the base. In the embodiment shown the beams 12 are of I-section. Each beam extends from a respective one of two opposed limbs of the central post, with the central web of the beam being coplanar with its associated limb of the central post (see 15 Figure 3). The beams 12 connect with the base 8 at their lower ends. A reinforcing web 14 extends from the post 2 downwardly between the two inclined beams and is coplanar with the other two limbs of the central post. At its lower end, the reinforcing web 14 extends radially outwardly across the aperture 10 to connect with the base 8. The reinforcing web 14 is preferably flanged to increase its rigidity. 20 The spacer is moulded in one piece in a suitable plastics. It will be seen that one of the two beams 12 is shaped on its outer edge with a part-circular protuberance 16. That protuberance lies in the zone of a sprue 18 formed when the spacer is moulded and the flange around the outer edge of that protuberance shields the sprue 18 to reduce the risk of 25 injury caused by the projecting sprue to a person handling the product, thereby avoiding the need to remove the sprue as part of the manufacturing process. The central post 2 of cruciform section maximises the load carrying capacity of the spacer for a given amount of plastics material. The length of the post is readily adaptable to a 30 range of different heights by using appropriate mould inserts. The strength of the central post is such that spacer of substantial height (150mm or more) can be produced for use P \OPER\RSI\3N07841 -CAP doc-/ II l/2007 -3 when casting deep ground slabs or road slabs, for example. Despite the provision of the apertured base 8, the connection of the central post to the base by the divergent beams 12 and the central reinforcing web 14 provides a robust mounting for the central post and which is able to withstand the applied loads and provides significant resistance of twisting 5 of the post relative to the base. Although in the embodiment shown the central aperture 10 of the base is of square shape, it may be of other shape, circular for example. 10 A spacer of the form shown in which the reinforcing bar or grid bar is retained in the seat by means of a clip, is able to be coupled with the bar or by inverting the spacer, moving it downwardly to clip onto the bar and then allowing the spacer to swing downwardly about the bar into its correct orientation with the base downwards. The added weight at the lower end portion of the spacer provided particularly by the divergent beams assists that 15 process. Figure 5 shows an alternative form of resilient clip 20 which retains the bar B in the bottom of the seat 4 for use in situations where the spacer is applied during the fabrication of continuous lengths of grid as may arise in the construction of roadways. 20 The embodiment has been described by way of example only and modifications are possible within the scope of the invention. Throughout this specification and claims which follow, unless the context requires 25 otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers.

Claims (7)

1. A spacer for concrete reinforcement, the spacer comprising a central post having at its upper end a seat for the reinforcement, and a substantially flat base with a central 5 aperture, the lower end of the central post being joined to the base by a pair of divergent beams extending to opposite sides of the aperture, the spacer being integrally formed as a one-piece moulding.

2. A spacer according to claim 1, wherein the central post is of cruciform cross 10 section and the two beams extend from one pair of opposite limbs of the post in the same plane as those limbs.

3. A spacer according to claim 1 or claim 2, wherein a central reinforcing web extends downwardly from the lower end of the post between the beams and is connected to the 15 base at opposite sides of the aperture.

4. A spacer according to claim 3 wherein dependent on claim 2, wherein the reinforcing web is coplanar with the other pair of opposite limbs of the post. 20

5. A spacer according to any one of claims I to 4, wherein the beams are of substantially I-section.

6. A spacer according to any one of claims I to 5 having at its upper end a clip for retaining reinforcing bar relative to the seat. 25

7. A spacer substantially as hereinbefore described with reference to the accompanying drawings.