AU2006100496A4 - Spacer for on-ground casting - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR AN INNOVATION PATENT Name of Applicant: Actual Inventors: Address for Service: Invention Title: ITW Construction Products Australia Pty Ltd Peter McLeod Brendan Andersen DAVIES COLLISON CAVE, Patent Attorneys, of 1 Nicholson Street, Melbourne, Victoria 3000, Australia "Spacer for on-ground casting" The following statement is a full description of this invention, including the best method of performing it known to us: Q.\OPER\RSH\Jan 06 June 06\12796150-164doc 13/6/06 P \OPER\RSHN\I27961 5-0no2 doc.-3 A)6M -1- SPACER FOR ON-GROUND CASTING The present invention relates to a spacer for supporting reinforcement or other components for incorporation into a cast product such as a panel, slab or beam. More particularly the invention relates to a spacer configured for use when casting directly onto the ground.

A spacer, usually known as a bar chair, for reinforcement to be incorporated into a cast concrete product, typically comprises an array of supporting legs, the lower ends of which rest against formwork. However, for applications in which the concrete component is being cast directly onto the ground, that type of chair is not suitable as the lower ends of the legs may sink into the ground under the weight of the reinforcement it is supporting, or may pierce a moisture barrier of plastic film. When used in such "on-ground" applications the chair must have a flat base. Similar considerations apply to spacers for other components which may be required to be cast in, for example an internally threaded ferrule to form an anchoring point within the finished concrete product.

Plastics bar chairs with an integral flat base tend to be produced in a very restricted range of sizes and current practice for some applications is to use a wire chair which sits on a base in the form of a metal tray. Although in common use, it is not particularly quick to install as the chair requires to be aligned with both the reinforcing steel and the base.

According to the present invention, there is provided in combination, a spacer for supporting a component for incorporation into a concrete product during casting thereof, the spacer having an array of supporting legs, and a separate base having a substantially flat undersurface, the base being configured to mate with the lower ends of the legs of the spacer such that the base is retained to the legs.

Further according to the present invention, there is provided a base configured for use with the combination defined above, wherein the base is substantially of annular form and includes at its upper surface zones into which the lower ends of the legs engage as a friction fit.

P \OPERRSHI27961 5o-mnnov2 doc-I36/O6 -2- Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a perspective view of a support base for application to a bar chair or other spacer to be used in on-ground casting; Figure 2 is a plan view of the base; Figure 3 is a section on line A-A of Figure 2; Figure 4 is a perspective view of a bar chair applied to the base; Figure 5 is a side view corresponding to Figure 4; and Figure 6 is a plan view corresponding to Figure 4.

As shown in the accompanying drawings, in accordance with a preferred embodiment of the invention there is provided a support base 2 of annular form with a substantially flat undersurface 4 which sits on the ground during casting. On its upper side the base 2 is of channel structure with a main annular channel 6 extending circumferentially around the base. The channel 6 is divided by an array of radially extending channels 8 equi-angularly spaced and which form zones adapted to engage as a friction fit with the lower ends of the legs of an associated spacer. As shown there are four such radial channels 8 but in other versions there may be a different number of such radial channels. In practice the base 2 is designed to inter-fit with a predetermined range of bar chairs (and/or other spacers) and for this purpose the configuration of the array of radial channels 8 is designed to mate with the lower ends of the legs of each of the spacers of the range. The interior of the base 2 is open except for diametral reinforcing ribs 10 which are also of channel form.

The base 2 is moulded in one piece in a suitable plastics material and the general channel form of its construction not only reduces the amount of plastics material while ensuring adequate rigidity. It also increases the range of applicability of the base, as will be described subsequently.

As mentioned above, the base 2 is designed to fit onto the lower ends of the legs of a bar chair or other spacer. Figures 4 to 6 show a plastics bar chair 12 applied to the base 2. The

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P\OPERRSHI127961 5O-nno2 doc-.13/)6A)6 -3chair 12 has four legs 14 and the base 2 is designed so that each one of the legs 4 is a friction fit at its lower end into a respective one of the radial channels 8. In the form shown, each of the legs 14 of the chair 12 is substantially of T-section and the width of each of the radial channels 8 corresponds to the length of the transverse stem 14a of the Tsection (see Figures 5 and 6) to provide a friction fit of the latter within the channel sufficient to securely retain the base 2 and chair 12 in their assembled relationship.

In practice a range of spacers is produced in which differ in leg length or in other characteristics but with a standard leg array in terms of cross-section at their lower ends, diameter of the array at its lower end, and angular spacing between adjacent legs. Any one of these spacers when required for "on-ground" application can then be mated with the base by pushing the lower ends of its legs into the radial channels of the base so that the spacer and base are then firmly connected. Accordingly a wide range of spacers can be made available for "on-ground" application without having to maintain a stock produced specifically for that application.

Although the base shown in the accompanying drawings features a single array of radial channels designed to fit with a range of spacers with the same basic leg configuration, the base could be produced with more than one array of radial channels for co-operation with one or more further ranges of spacers of different leg configuration. In fact, the base even without the incorporation of additional radial channels is able to be used with spacers of a different leg configuration. Depending on the size of the legs their lower ends may engage with a friction fit into the segments of the main annular channel 6 or into the channel structure of the diametral reinforcing ribs.

The embodiments have 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 otherwise, the word "comprise", and variations such as "comprises" or "comprising", will P \OPERRSHI 27%61 S0-nov2 doc- I 3.1)6 -4be 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.

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 (4)

1. In combination, a chair for supporting a component for incorporation into a concrete product during casting thereof, the chair having an array of supporting legs, and a separate base having a substantially flat undersurface, the base being configured to mate Swith the lower ends of the legs of the chair such that the base is retained to the legs. \O

2. A combination according to claim 1, wherein the base is substantially of annular form and includes at its upper surface zones into which the lower ends of the legs engage as a friction fit.

3. A combination according to claim 2, wherein the upper surface is shaped to provide a circumferential channel which is divided by an array of radial channels each of which defines a respective said zone.

4. A combination according to any one of claims 1 to 3, including at least one group of chairs of different dimensions or other characteristics but having a common leg configuration at least at their lower ends whereby the base is able to fit onto any selected one of the chairs of the group. A base configured for use with the combination according to any one of claims 1 to 4, the base having a substantially flat undersurface and zones at its upper surface to engage with the lower ends of the legs of the chair with a friction fit. DATED this 13 th day of June 2006 ITW CONSTRUCTION PRODUCTS AUSTRALIA PTY LTD by their Patent Attorneys DAVIES COLLISON CAVE