Patent Application
20060011801
The present invention relates to a system for retaining solid fill in a plastic state. The invention particularly relates to concrete formwork, although other possible uses of the invention are foreseen such as garden or sandpit edging, or any form of earth retaining wall.
Presently, retaining walls to retain concrete and other types of solid fill which may be initially or permanently in a fluid state are typically made from timber boards of various sizes. When used for earth retaining walls, garden or footpath edging, the timber remains in position for long periods of time. When used for concrete formwork, the timber is nailed together in the required configuration and disassembled when the concrete has set.
There are a number of problems associated with the use of timber in the above applications, both due to the nature of the material and the means of assembling the timber into the required structure. In general, the assembly of the retaining structure is lengthy and labour intensive. This is particularly the case when timber is used to construct concrete formwork when more complex concrete structures are required, such as steps for drop edges.
In the case of concrete formwork, the life span of the timber used is shortened by the build up of concrete adhering to the surface, splits in the timber, and the many holes that appear due to the use of nails to secure the timber boards. In the case of garden edging, or any similar use of timber in which the timber remains in position, the timber rots over longer periods of time. Timber has the additional problem of storage in that it must be kept inside or covered to prevent it from rotting and warping.
In the case of garden or footpath edging, timber also cannot readily be used to create curved edging.
The use of plastics to produce concrete formwork has been proposed to address some of the above mentioned problems associated with the use of timber, for instance in EP 0353637A, U.S. Pat. No. 6,117,521A and U.S. Pat. No. 5,632,923A. However, the use of plastics has, to date, not been commercialised, and the use of timber is still widespread. Problems associated with the use of plastics include finding an economic, convenient and easy to use means of connecting plastics boards to each other, which is also versatile enough to be useable to create more complex structures such as steps for drop edges. For instance, the system of U.S. Pat. No. 5,632,923 requires a number of different connectors which are complicated to assemble. Furthermore, the connectors require holes which are predrilled in the face of the plastics boards, and it is necessary to fill unused holes before the concrete is poured to prevent concrete from spilling through the holes. Furthermore, the system of U.S. Pat. No. 5,632,923 can only be used to construct planar retaining walls, and not step structures, or curved structures.
According to the present invention, a retaining system includes:
a retaining section;
a coupler for releasably coupling to the retaining section; and
means for fixing couplers coupled to adjacent retaining sections to each other to thereby maintain adjacent retaining sections in fixed relationship to each other.
According to a second aspect of the present invention, a retaining system includes:
a retaining section;
a coupler for releasably coupling to the retaining section; and
means for fixing the coupler to a supporting substrate to thereby maintain the retaining section in fixed relationship to the supporting substrate.
The system of the present invention is preferably easy to assemble and versatile. By connecting the retaining sections by the use of couplers which are connected to each other, rather than by directly connecting the retaining sections to each other, a versatile system is produced which can be adapted to construct more complex structures such as steps. The couplers preferably protrude from the retaining sections and can be connected together such that the retaining sections are offset with respect to each other, producing a structure suitable for forming a concrete step. Alternatively, the retaining sections may be aligned with each other to produce a planar retaining wall.
Furthermore, the coupler provides a convenient means for maintaining the retaining section in a fixed relationship to a supporting substrate, which may be the ground or a floor of a building. The couplers are fixed to the supporting substrate, rather than directly fixing the retaining section.
The couplers are releasably connected to the retaining sections to allow quick assembly. Preferably, once coupled to a retaining section, a coupler is slidable along the retaining section. This allows adjustment of the coupler position to align with couplers on adjacent retaining sections, before the couplers are connected to each other and/or to the supporting substrate. Again, this facilitates assembly of the retaining system.
Preferably, the couplers are connected to each other by connecting means, the connecting means preferably comprising a rigid member to which the couplers are fixed. Preferably the connecting means also connects the couplers to the supporting substrate. Preferably, the means for fixing couplers coupled to adjacent retaining sections to each other and the means for fixing a coupler to a supporting substrate comprises at least one hole in the coupler for fixing the coupler to the connecting means. The coupler is fixed to the connecting means by a nail or screw which passes through the hole.
Preferably, the retaining section is formed from plastics, more preferably extruded plastics. The use of plastics overcomes the problems associated with the rotting of timber. The plastics has a longer lifetime and is more resistant to degradation than timber. Furthermore, plastics is recyclable. For applications in which the retaining system remains in position, such as garden edging and earth retaining walls, plastics has the advantage of being long lasting and resistant to weathering. The plastics can also be given a number of different finishes e.g. a sand effect finish. Furthermore, the retaining sections can be extruded in a number of different shapes, and particularly can be made to curve.
For the application of the retaining system to concrete formwork, the use of plastics has the additional advantage that concrete does not adhere well to plastics. With the prior art use of timber, it was not possible to strip the boards from the concrete until the concrete had completely dried. With the use of plastics, the formwork can be stripped from the concrete much earlier. This can save a number of man-hours because it is unnecessary for someone to wait as long for the concrete to dry to remove the formwork, or for someone to return to a site after work has been completed to remove formwork. The present inventors have found that plastics formwork can be stripped 1 to 2 hours earlier than timber formwork.
Preferably, the coupler is additionally formed from plastics.
Preferably, the connecting means comprises a wooden post to which the couplers are nailed or screwed. In assembling the retaining system, the wooden post is driven into the ground. Preferably, the coupler includes a plurality of holes such that it can be connected to the wooden post at a plurality of different positions. This enables the retaining sections to be fixed such that faces are off set from each other, to allow the construction of formwork for producing steps for drop edges.
Preferably, the retaining section is a C-section. Preferably, the coupler is adapted to interlock with the C-section. Preferably, this is achieved by means of a pair of slots, one on each side of the coupler which engage in the C-section. The coupler can be easily engaged with the retaining section by placing it in the C-section and rotating it such that the slots engage with the C-section. This means of engagement makes the system extremely easy to assemble and requires no screws or bolts, or holes in the retaining section. When engaged in the C-section, the coupler can slide along, to enable it to be secured at any point within the length of the C-section, and to align it with couplers on adjacent retaining sections.
According to a third aspect of the present invention, a coupler for a retaining system comprises:
a member having two slots for interlocking with a C section at a first end, and a plurality of holes for fixing to a connecting member at an opposite end.
Preferably, the retaining system is a concrete formwork system.
Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, in which:
a is a perspective view of a retaining section;
b is a perspective view of a coupler;
As shown in
As shown in
The coupler 2 is coupler to the retaining section 1 by inserting the coupling section at an angle into the recess between the rear plate portions 1d, 1e, and turning the coupler 2 to engage the slots 3, 4 with the rear plate portions 1d, 1e of the retaining section 1. The coupling section 5 is slightly narrower than the main body 6 (which is substantially the same width as the retaining section 1) to allow it to be rotated inside the retaining section 1. The rounded corners 6, 7 allow rotation in one direction only. The main body 6 of the coupler 2 has an array of holes . Once the coupler 2 is engaged in the retaining section 1, it can slide along the retaining section 1 to be located at any desired point.
It is possible to create a planar vertical retaining wall as illustrated on the left-hand side of
Although the present invention has been described particularly with reference to concrete formwork, the present invention can also be applied to other applications such as earth retaining walls, garden or footpath edging.
In one embodiment of the retaining system, retaining sections 1 are provided in different sizes, particularly different widths eg 100 mm, 150 mm, and couplers 2 are provided to match each width of retaining section 1. The couplers 2 and retaining sections are colour coded such that matching couplers and retaining sections are the same colour. The colour also signifies size and varying composition of the material.
For the purposes of this specification it is to be clearly understood that the word “comprising” means “including but not limited to”, and that the word “comprises” has a corresponding meaning.
Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.
