AU2007221911A1 - A formwork device - Google Patents

Description

0 o P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: "A FORMWORK DEVICE" The following statement is a full description of this invention, including the best method of performing it known to me/us:

TITLE

A FORMWORK DEVICE 0 FIELD OF THE INVENTION THIS INVENTION relates to a formwork device. In particular, the invention relates to a formwork device to assist in placing foundations for domestic buildings. However, it should be appreciated that the formwork device may be used for other in-ground applications in which concrete is to c be located within a trench.

OBACKGROUND OF THE INVENTION In-ground foundation work is required in many domestic building applications. Typically in-ground foundation work includes digging a trench, locating reinforcing bars within the trench and pouring concrete into the trench. Once the concrete is set, this provides the foundation for a house.

The building industry is a very competitive industry.

Accordingly, the prices for housing are driven downwardly and hence profit margins are relatively low. Therefore, any discrepancy between an estimated cost and an actual cost can have a large impact on the profitability of the building a house. One such cost, that is difficult to estimate, is the inground foundation work.

When building a house, it is easy to determine the theoretical size of the in-ground concrete beam that is required to provide sufficient support for the house to be built. Estimating the cost of the theoretical size beam is also relatively easy. The dimensions of the beam are multiplied to calculate the volume of concrete which is required which is then multiplied by the cubic metre cost of the concrete. The cost of the reinforcing bars is added as well as the related labour cost. The concrete, reinforcement bar and labour costs are added to calculate the total estimated cost of the inground beam.

However, when preparing a trench so that the foundation work can be laid, the trench is invariably not a perfectly rectangular shaped prism.

This is especially the case when the house is to be built on dry, powdery soil.

OL

The important strength criteria for a concrete beam is the depth of the concrete beam. Therefore, so long as the trench is of sufficient depth, it is O not structurally important that the beam is not a rectangular shaped prism.

However, from an estimating point of view, if the trench is not a rectangular shaped prism a substantial amount of additional concrete is required. This additional amount of concrete is often up to double the amount estimated which substantially increases the actual cost of the in-ground foundation Swork.

OIn order to overcome the additional requirement for concrete, formwork can be located within a trench to ensure that the beam is a substantially rectangular shaped prism and the estimated volume of concrete is used. However, this requires additional labour time in order to place and then remove the formwork. The additional labour cost is often higher than the cost of the additional concrete and, hence formwork is not normally used.

OBJECT OF THE INVENTION It is an object of the invention to overcome and/or alleviate one or more of the above disadvantages and/or to provide the consumer with a useful commercial choice.

SUMMARY OF THE INVENTION In one form, though not necessarily the only or broadest form, the invention resides in a formwork device comprising: a formwork member to provide containment of setable material; and at least one locating tab pivotally mounted to said formwork member.

Normally there are a plurality of locating tabs. Preferably each locating tab is independently pivotally movable with respect to the formwork.

Preferably the locating tabs and the formwork member are integrally formed.

Preferably the formwork device is made from dimensionally stable material that is relatively inexpensive and disposable.

Preferably the locating tabs are independently movable with respect to each other. At least one aperture may extend through each of the locating tabs.

'3 Preferably the formwork apparatus is made from water resistant material. For example, the formwork device may be made from 0 corrugated plastic or fibre board.

In another form, the invention resides in a method of preparing a trench for the pouring of a suitable material, the method comprising the steps of: placing a formwork device within a trench so that the formwork N, member of the formwork apparatus is substantially vertical; and placing a ground engagement member through at least one of the CN 10 locating tabs of the formwork device into a ground surface.

The ground engagement members may typically be pegs.

In yet another form, the invention resides in a method of producing a formwork device from a fluted sheet, the method including the steps of: cutting one of two walls of the fluted sheet to hinge a locating tab to the formwork member.

The method may also include the step of cutting the fluted sheet to produce two formwork devices.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will be described with reference to the accompanying figures in which: FIG. 1 is a perspective view of a formwork device according to a first embodiment of the invention; FIG. 2A is a plan view of a sheet of material with cut lines from which two formwork devices are produced; FIG. 2B is a plan view of a two formwork devices that have been produced from the sheet of material of FIG. 4A; FIG. 3A is a perspective view of two formwork devices of FIG. 1 located above a trench; FIG. 3B is a perspective view of two formwork devices of FIG. 1 located within a trench; 4 O FIG. 4A is a side view of two formwork devices of FIG.1 located (-i within a trench; O FIG. 4B is a side view oftwoformwork devices of FIG.1 forming a mould for concrete; FIG. 5 is a perspective view of a formwork device according to _a second embodiment of the invention; _FIG. 6 plan view of a two formwork devices that have been (-i c- produced from a single sheet of material; FIG. 7A is a side view of two formwork devices located within a c 10 trench; and FIG. 7B is a side view of two formwork devices form a mould for concrete.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a perspective view of a formwork device 10 that is used to produce an in-ground concrete beam. The formwork device includes a formwork member 20 and a number of locating tabs The formwork member is elongate and rectangular in shape.

The locating tabs are trapezial in shape and are individually hinged with respect to the formwork member. Apertures 40 are located adjacent each of the ends of each of the respective locating tabs.

The formwork device is made from corrugated plastic sheet as shown in FIG. 2A. The corrugated plastic is formed using two thin walls 51 which are spaced apart by flutes 52 that run transversely across the length of the corrugated plastic sheet 50. A single sheet as shown in FIG.

2A can be cut to provide two formwork devices 10 shown in FIG. 2B.

Further, one of the two walls of the corrugated plastic can also be cut adjacent to where the locating tabs 30 and formwork member 20 join in order to provide a hinge so that the locating tabs can pivot with respect to the formwork member In use, the formwork device 10 is positioned so that it is located within a trench 60 as shown in FIG. 3A and FIG. 3B. Normally the formwork member 20 is required to be substantially horizontal. The locating tabs N extend outwardly from the formwork member 20 and touch the ground 61. At this point, pegs 70 are pushed through the apertures 40 in each of the 0 locating tabs 30 and into the ground 61 as shown in FIG. 4A. This holds the formwork member 20 in its desired horizontal position. This process is repeated for a second formwork device 10. Once both formwork devices are positioned as desired within the trench 60, reinforcement bars are positioned within the trench 60 and concrete poured over the reinforcement C bars to form a concrete beam, as shown in FIG. 4B.

When the concrete is set, the entire formwork device 10 can be S 10 removed. Alternatively, the locating tabs 30 can be torn from the formwork member 20 and the formwork member 20 left within the ground.

FIG. 5 and 6 show an alternative embodiment of the formwork device 110. In this embodiment there are locating stubs 131 and locating tabs 130 that are independently hinged to the formwork member 120.

Apertures 140 are again located adjacent the ends of both the locating stubs 131 and the locating tabs 130. Again, two formwork devices 110 are produced from a single sheet 50 of corrugated plastic.

The locating tabs 130 are used as described above. The Locating stubs 131 are used when the locating tabs 130 are unable to reach the sides of a trench 160. Long pegs 170 are placed through the apertures 140 in the locating stubs and into the ground 161 as shown in FIG. 7A. The pegs 140 not only anchor the formwork device 110, but the pegs 170 also help in supporting the formwork member 120 in use. Once the formwork devices 110 are positioned, reinforcement bars and concrete is poured between the formwork members 120 to form the concrete beam as shown in FIG. 7B.

This invention provides a simple, cost effective and time conscious way in which to accurately produce in-ground concrete beams.

Accordingly, correct estimates can be provided with certainty allowing for reasonably short profit margins.

6 ,1 It should be appreciated that various other changes and Smodifications may be made to the embodiments described without departing 0 from the spirit or the scope of the invention.

Claims (16)

1. A formwork device comprising: O a formwork member to provide containment of setable material; and at least one locating tab pivotally mounted to said formwork member.

2. The formwork device of claim 1 wherein there are a plurality of locating tabs.

3. The formwork device of claim 1 wherein the at least one locating tab is c independently pivotally movable with respect to the formwork.

4. The formwork device of any one of the preceding claims wherein the C 10 at least one locating tab and the formwork member are integrally formed.

The formwork device of any one of the preceding claims wherein the formwork device is made from dimensionally stable material.

6. The formwork device of claim 2 wherein the locating tabs are independently movable with respect to each other.

7. The formwork device of any one of the preceding claims wherein at least one aperture may extend through the at least one locating tab.

8. The formwork device of any one of the preceding claims wherein the formwork device is made from water resistant material.

9. The formwork device of any one of the preceding claims wherein the formwork device is made from corrugated plastic or fibre board.

The formwork device of any one of the preceding claims wherein at least one locating tab is trapezial in shape.

11. The formwork device of claim 1 wherein the formwork device is made from a fluted sheet having two walls, one of the walls being cut to hinge the at least one tab to the formwork member.

12. The formwork device of claim 1 includes at least one locating stub that is pivotally mounted to said formwork member.

13. A method of preparing a trench for the pouring of a suitable material, the method comprising the steps of: placing a formwork device within a trench so that the formwork member of the formwork apparatus is substantially vertical; and 8 Splacing a ground engagement member through at least one of the Slocating tabs of the formwork device into a ground surface. O

14. The method of claim 13 wherein the ground engagement members are pegs.

15. A method of producing a formwork device from a fluted sheet, the method including the steps of: cutting one of two walls of the fluted sheet to hinge a locating tab to Ci the formwork member.

16. The method of claim 15 including cutting the fluted sheet to produce c- 10 two formwork devices.