TITLE FORMWORK FOR LANDSCAPING EDGING.

FIELD

This invention relates to prefabricated border-defining means (herein called formwork) that assist in creation of concrete borders or edging upon the ground in a landscape, garden, playground or the like along predetermined lines. The border-defining means will hold wet cement in shape until the cement has set as concrete thereby forming an edging.

BACKGROUND

Previous methods for making a border or an edging for use in lawns or gardens, and by landscapers in order to separate one area from another include:

1. Use of strips of wood or other material laid along a line, the material itself forming an edge.

2. A line of bricks placed end-to-end, or other masonry, or rocks is embedded in a trench or is simply placed on the ground. Subsequent movement, and penetration by invasive plants are two common problems resulting in early deterioration.

3. Pouring concrete inside wooden boxing (shuttering or formwork), usually constructed on the site. This is labour and materials-intensive. The concrete might be wide enough to serve as a path. It might include reinforcing as iron rods.

4. Pouring concrete inside vertically oriented rubber-like strips, which have been pegged in place before pouring, but which tends to form sinusoidal edges, wider where the edges are forced apart.

5. Extruding concrete by means of a proprietary machine known as a curbing machine, which extrudes a continuous column or strip of concrete or mortar into a trench or onto the ground. (Costs per lineal foot are significant, and internal reinforcing is not possible).

Bricks or other masonry may be laid either along or across the concrete in one course or more. Selection of any one method from either the list above or from the prior art below depends to some extent on the strength and degree of permanence required, the amount of skill available, and the cost of machinery, parts, and labour.

The above methods have not solved the problem of providing a strong, durable, neatly finished edging, one for which the prefabricated components to be used are light in weight.

PRIOR ART

There are a number of patent publications in relation to landscape edging in general. Allen et al. in US 6629383 describes a type of formwork used to segregate dissimilar landscaping schemes by positioning the device into the soil. The invention is made of flexible strips, designed for continuous end-to-end attachment that are attached to the soil by removable stakes. The edging system is designed so that stakes are part of the edging portion of the device. The width of the result tends to vary, since the weight of concrete tends to push the sides apart if no restraining stake is present resulting in wiggly edges as mentioned previously.

Staten et al. in US 6591547 describes another family of edging products: wherein the material sold is pre-formed blocks having bidirectional, interlocking joints. Foster in US 6625925 describes yet another kind of landscape ending, in which a modular extended bent panel having a decorative outer surface is joined lengthways with others, and mulch etc may be concealed within the bend. Mclntyre et al. in US 6324783 describes an integrally moulded plastic landscape edging strip with integrally moulded spikes to penetrate the ground. Ireland in US 4647491 described use of fluted board (one common form being made in polypropylene), cut into strips so that the flutes will lie vertical, then simply staked into the ground using pegs passing through the flutes. Hairpin pegs join strips edge-to- edge. Winter, in EP 0866196 also uses fluted board to make sacrificial shuttering, formwork or boxing for building foundations. A user bends a sheet of fluted or corrugated board into a "U" shape of a required size and places the shape in a trench in the ground. A steel reinforcing cage is then placed inside and concrete is poured inside, thereby forming a reinforced ground beam. Transverse clips or bridges are not taught.

OBJECT

It is an object of this invention to provide a landscaping guide or formwork for the in-situ pouring of edging, or at least to provide the public with a useful choice.

STATEMENT OF INVENTION

In a first broad aspect this invention provides formwork for retaining a settable fluid material, such as concrete, in place until the material has set into an elongated strip having a width and a depth and thereby becomes a horticultural, garden or landscape edging capable of demarcating a first area on a substrate from a second area, wherein the edging system comprises a generally U-shaped channel unit having a defined width and depth and sufficient lateral strength to maintain the width while holding a

settable fluid material selected from a range including (without limitation) cement and mortar within the channel until the fluid material has set.

Preferably the sacrificial channel unit is comprised of a base and two sides each extending upwardly from the base and supporting a top edge at a controlled height, each top edge being separated by a controlled width from the other top edge, and the or each unit includes at least one bridge arranged in use to extend transversely across the unit between the two sides; the formwork being sufficiently stiff to prevent noticeable deformation caused, when in normal use, by forces exerted by the settable fluid material.

Formwork as previously described in this section, wherein a channel unit having a generally U-shaped cross-section and a controlled width is manufactured as part of a range of units each having two open ends, the range including (a) a substantially straight channel having one of a range of set lengths; (b) a curved channel having a controlled radius of curvature about a vertical axis and a selected length such that an arc in a range of from about 5 degrees to about 90 degrees is provided, (c) a curved channel having a controlled radius of curvature about a horizontal axis and a length such that the channel unit forms an arc in a range of from about 5 degrees to about 45 degrees to the other, and (d) a channel including a sharp corner having a controlled angle wherein one end is arranged at an angle in a range of from about 30 degrees to about 120 degrees to the other and including a right-angled corner; and wherein a plurality of channel units are mutually engageable by their ends in order to define a continuous elongated channel having a controlled width along the plurality of said units.

Alternatively, a channel unit having a generally U-shaped cross-section and a controlled width may be manufactured in the form of a junction unit having an outline of a "T" or of an "X" with more than two open ends.

Preferably each element of the formwork includes at least one substantial aperture in the base of each channel unit, so that when in use the aperture allows settable fluid contained within the channel unit to flow out through the aperture and lie within a space between the channel unit and the underlying substrate.

Preferably "the apertures comprising at least 15% of the total base area, and more preferably they comprise at least 65% of the total base area.

In a version of the formwork having removable side shutters, there is no base and the aperture percentage is then substantially 100%.

In one option the cross-bridge comprises an integrally formed component of the channel unit.

In another option, the or each bridge comprises a separate element engageable with the channel unit.

90 Preferably, the top surface of the bridge is entirely below the top edges of the two sides, so that in normal use the bridge will be entirely immersed in the settable fluid contained between the sides.

Alternatively the top surface interrupts the concrete so that a shrinkage crack is defined at that place.

Preferably the top surface of the bridge is notched with at least one notch in order to be capable of supporting at least one elongate beam extending along the line of the channel unit and immersed 95 within the settable fluid; the beam being selected from a range including reinforcing iron, electrical cables, and water pipes.

Preferably each bridge includes at least one lengthwise directed aperture between the top surface of the bridge and the base of the channel unit, so that when in normal use settable fluid placed in the channel unit can flow under the bridge and merge with itself through the aperture, thereby increasing the 100 strength of the resulting edging.

Optionally the channel units are provided with asymmetric walls including a version where one side is higher than the other.

In a second broad option, the base and sides of the U-shaped (in section) channel unit are formed from a flexible, circumferentially corrugated material (resembling "Novaflow" drainage pipe), so that in use 105 the corrugations can be compressed together on one side of the channel unit and stretched out on the other, to flex the channel unit about an axis yet maintain a substantially constant width between the sides of the channel unit.

In a third broad option, the base and sides of the or each channel unit are located prior to hardening of the settable fluid material by use of a plurality of holding frames placed on or pushed into the 110 substrate.

In a further option, subsequent removal of the sides from the holding frames is provided for, after the settable material has cured sufficiently.

Prefsrably the sides are formed of a material capable of undergoing degradation after the settable material has cured sufficiently.

115 In a fourth broad option, the invention provides a method for creating an edging, wherein the method includes the steps of:

a. Laying out a course along a substrate along which the edging is to run;

b. Optionally making a shallow trench cut into the substrate, in order to locate and/or set the height of the formwork.

120 c. fitting formwork into the course, the formwork comprising a channel unit having a generally U- shaped cross-section comprised of a base and two sides extending upwardly from the base, and a plurality of upwardly notched bridges extending between the sides, above the base, d. pouring a settable fluid material into the formwork to fill the channel unit above the level of said notched bridges so that the material, once set, becomes the edging,

125 e. and screeding the top surface to provide a suitable finish.

An optional further step is to place at least one elongate member along the notches in said bridges before covering the at least one elongate member with the settable fluid material, thereby providing internally reinforced edging.

Optionally the top surface of the concrete is provided with a drainage channel.

130 Optionally, one or more courses of masonry or other wall material is/are placed over the concrete once the settable fluid material has hardened, or while still wet.

Optionally, at least visible parts of the sacrificial formwork are removed after the fluid material has set.

Preferably the sides are formed of a material permitting hand or machine tearing, cutting or stripping 135 of the sides or at least that part visible above the substrate, and perforations may be provided to facilitate tearing.

In a fourth related aspect the formwork provides for at least partial disposal of the walls after the settable material has set into a solid form.

In a fifth broad aspect, the invention provides at least one three-dimensional mould for making shapes 140 from thermoplastic sheets, characterised in that the or each mould is configured so as to be suitable for making a channel unit as previously described in this section for use in formwork.

Preferred moulds are compatible with the preferred vacuum-forming process.

Optionally the channel units are made by cutting and pressing a sheet of degradable corrugated board made of a formable material in a configuration wherein a sandwich of corrugated material is provided 145 with a flat surface on at least one side. hi a yet further aspect the formwork of the invention, when comprised of an indefinite length of a

flexible, corrugated material, is formed from a stiff flexible plastics material.

PREFERRED EMBODIMENT

The description of the invention to be provided herein is given purely by way of example and is not to 150 be taken in any way as limiting the scope or extent of the invention. Throughout this specification, unless the text requires otherwise, the word "comprise" and variations such as "comprising" or "comprises" will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

DRAWINGS

155 Fig 1 : is a perspective view of a channel unit of formwork, cut from fluted polypropylene board according to the invention (prototype version).

Fig 2: is an end elevation view of a moulded item of formwork 200;

Fig 3 : is a plan view 300 of part of an item; and

Fig 4: is a side elevation view 400 of part of an item. 160 Fig 5 : is a perspective view of a complete item 500.

Fig 6: is a perspective view of a quarter-circle prefabricated item 600.

Fig 7: is a perspective view of a 45 degree corner item 700..

Fig 8 : is part of an item of formwork illustrating some possible edge formations.

Fig 9: illustrates an item comprising a short straight length including an incline (or decline). 165 Fig 10: illustrates an item comprising a straight length including a corner at one end.

Fig 11 : illustrates sacrificial pegs used to locate edging, and shutters.

Fig 12: as 12a and 12b, illustrates an insertable cross-bridge for a corrugated pipe type of formwork.

Fig 13: as 13a and 13b, illustrates two rollers suitable for shaping the surface of the poured concrete.

Fig 14: illustrates an "X" junction. 170 Fig 15 : illustrates a "T" junction.

Fig 16: illustrates a segmented version of formwork, wih units joined by strips at each side.

The edging system for gardens and landscaping to be described herein comprises a variety of prefabricated sacrificial shuttering units or formwork (which are not re-usable) having a "U" section,

175 to delimit straight lines, corners, risers, and curves all having a consistent width and depth. Vacuum-

formed moulded plastic sheeting is preferred. Selected units may be joined end to end, and may be cut to length. They include repeated internal cross-bridging formations that improve stiffness and support optional internal reinforcing metal bars, water pipes or electric cables along grooves while concrete is poured to fill the formwork. A masonry wall or drainage channel may be constructed on top. The 180 invention could be used to serve as a barrier to invasive weeds. Typically, the invention would be used by landscapers or gardeners when dividing an area into portions serving different purposes such as lawns or gardens and it may have on-farm applications.

The inventors set out to provide prefabricated formwork that will hold poured concrete (or other settable material) in place in elongated horizontal beam form until it has been cured, and which can

185 optionally include one or more bars of internally located reinforcing iron (and possibly also water pipes or electric cables for distribution about a landscape or garden) within the horizontal concrete beam. In relation to size, the inventors assume that the majority of demand for the invention will comprise moulded units that are either about 140 mm wide, or 250 mm wide at the top, (the distance between walls 105 and 106 of Fig 1). The above dimensions are suitable for use as a base for walls

190 using standard brick sizes. There are of course many other possible convenient dimensions. It is important to note that those sizes are given by way of example only.

Briefly, a method for using the invention comprises these steps:

1. Planning the edging, perhaps transferring an actual layout made on the site on to a plan or by planning in the first instance, then deciding on the necessary quantities and types of formwork to be

195 acquired.

2. Preparing the surface by stripping off vegetation or making trenches, if required to drop the top surface in relation to the surrounding ground.

3. Placement of formwork (perhaps involving cutting to length) and insertion of any reinforcing material, cables or pipes.

200 4. Filling the formwork with a settable material such as concrete, and finishing off the top surface as required (either smooth, or with a drainage channel, or roughened to bind better to mortar used for a subsequent wall). Usually, ensure that the concrete flows through bottom apertures to contact the ground, and makes contact under cross-bridges.

5. In order to make the formwork disappear after serving its purpose, it can be torn or cut from

205 areas of the edging where it remains exposed, or it is pre-weakened as with perforations, or optionally it is made of a degradable or biodegradable material that will rust, corrode, or rot away in time.

(Alternatively the formwork can be regarded as "decorative" in its own right.

EXAMPLE 1

Fig 1 shows an early prototype channel unit 100, having ends 101 and 102, floor 103 and side walls

210 105 and 106. It comprises a U-shaped piece of partly cut and then bent planar material conveniently made of a stiff yet flimsy polypropylene material known as "flute board" although the same principles of construction can be applied to alternative materials to be described below. End-to-end connections or joints are made between units of formwork, providing indefinitely long runs of edging. The floor may be incomplete as shown by cut-out aperture 104. One purpose of this large aperture is so that the

215 concrete can flow to the solid bottom of the trench, or underlying surface. If the weight of the concrete was to be supported by the formwork alone as it bridges a gap, the channel unit might fail before the concrete sets, or the concrete may break later under a force from above. Preferably some parts of the floor of the formwork are left intact such as at the ends 102, 103 and perhaps also in the middle. These provide strength, to stop the sides from spreading apart, and stop the channel unit from collapsing.

220 Hole areas for any of the Examples described herein are typically from between about 15% to about 65% of the total base area (100% in the case of Example 4 as described below). The intact floor sections will be useful for the purpose of cutting the channel unit to fit into a defined length. The inventor also provides pre-printed cutting guides such as the dotted lines (shown here at 108 and printed at intervals of for example 100 mm along the length of the channel unit, so that an installer can

225 make angled joints such as at 60 and 90 degrees by cutting along the lines. A number of transverse bridges or clips 107, 107A, 107B, 107C, 107D have been inserted in the channel unit. (The one at 107D is not shown). Each of these has a serrated upper edge that provides typically 3 valleys, or any number from 1 up to 5 or more valleys across the top. A straight item such as a beam of reinforcing iron or a water pipe may be laid along a series of valleys.

230 Then concrete can be poured into the interior of each unit of formwork while the position of each valley maintains the straight item in place well inside the perimeter of the concrete, for better rust prevention and strength. The bridges or clips also provide transverse strength for the unit before the concrete has set. After the concrete has poured and hardened (cured), any channel unit material that is or may become visible can be torn away, or cut away with a knife. After a suitable curing period,

235 optional block work may, if desired, be laid on top. This includes the commonly preferred fired-clay bricks. If an advance of corrosion from below any of the cross-bridges is feared, the straight item or items may instead be supported on hanging stirrups.

If reinforcing iron has been used the concrete edging should (after curing) be strong enough to bear the

weight of a passing vehicle without breakage. This flute-board prototype has become largely 240 redundant in the inventors' view, owing to the advantages of vacuum-formed plastics in particular,

EXAMPLE 2

Suitable constructional materials are economical to produce yet are sufficiently strong to withstand forces imposed during construction and until the filling material has set. Wooden or metal materials - even thin, pressed sheet metal - may be considered but carry significant cost and fabrication penalties. 245 It is useful to consider other manufacturing options, particularly those employing other kinds of plastics material that are formed into shapes visually or functionally similar to those outlined in Example 1 by methods known to those skilled in the art, some of which are reviewed here.

1) Vacuum forming (also called thermoforming ). This is the preferred method of shaping flat sheets of a thermoplastics material for the present invention. This method comprises making a flat sheet hot

250 and therefore flexible by use of infra-red radiation or hot gas, and then forcing the softened sheet by use of gas pressure (including use of a vacuum inside the mould or gas pressure applied from outside, or both) into a previously shaped, re-usable mould, so that the sheet adopts the shape of the mould, then turning the finished article out after it has hardened sufficiently. The thin material cools quickly so that the mould can be re-used without a long wait. Final sheet thickness is a function of original

255 thickness and the amout of areal expension imposed by the moulding process. Preferably, as shown in the illustrations, the product walls are equipped with corrugations during during the forming process, for extra strength or so that the amount of plastics used can be minimised.

Polystyrene sheet is an example of a commonly used thermoplastics material. Supplies of recycled polystyrene are readily available for this purpose in a preferred black colour (hiding inadvertent 260 coloration) which is less obtrusive in a garden setting if exposed and not removed. Polystyrene or other recycled plastics/ rubber compositions may be useful.

For lower labour input, a material permitting degradation (such as rotting, corrosion, dissolving, burning, or disintegration) of the sides of the formwork after the settable material has cured sufficiently may be used. This material includes certain biodegradable plastics or may be a cellulose- 265 based material such as a paper pulp or papier mache material that is slip-cast or pressed or otherwise formed by techniques that are well-known for such materials. Alternatively the sides are formed of a material permitting hand or machine tearing, cutting or stripping of the sides or at least that part visible above the substrate, and adaptations for removal of this type might include weakened tear lines cut into each item of formwork.

270 Examples of guides for landscaping produced by this method are as shown in Figs 2 to 10, which will be discussed below. The inverted "U" section or profile is consistently provided in units of formwork manufactured in this way; whether intended for straight, curved or bent runs of edging, so that the eventual concrete beams will have a consistent width.

2) Rotational moulding is a technique that forces material into a previously shaped, re-usable mould 275 often made of cast aluminium by centrifugal force. Suitable plastics include low, medium and high density polyethylene, polypropylene, polyamides (nylons), polyvinyl chloride, etc. The method appears to be tolerant to the use of recycled plastics which may not be as pure as virgin plastics. Again, black is a preferred colour. The plastics are commonly introduced into the mould as ground, pulverised or powdered raw materials.

280 3) Blow moulding is another known technique for forming shapes, though it is more applicable to closed containers. A blow moulded container of suitable dimensions could be cut in half to form two "U"-shaped channels according to the invention.

4) Injection moulding, including co-moulding with metal stiffeners, is an option. The material to be moulded is hot enough to flow and is supplied under high pressure, unlike the previous methods, so

285 that the moulds which may be some metres (2.4 m?) in length are more costly than for the previous examples which are carried out at more or less atmospheric pressure. The cooling cycle takes longer. Sprues may require trimming. A very wide range of thermoplastics and some thermosetting materials (if introduced before the cross-linking reaction) are available for this process, as is well known to workers in the art, but there is a risk when using recycled plastics that contamination may be abrasive

290 to injectors and dies when used with this technique.

5) Moulding (or extruding) of polystyrene foam shapes, starting with dense grains that expand when exposed to the temperature of the mould, is another option. The process can be controlled to make relatively dense, strong shapes.

6) Extrusion forming is widely used such as for spouting along roof edges, and could be adopted for 295 formwork of the present invention at least for straight runs. Cross bridges could be produced by a spaced-apart deformation process, repeated at intervals while the material is still hot, or could use separate pieces, glued or ultrasonically welded or RF-welded into place.

7) A roll of flat metal strip of indefinite length, perhaps about 250-350 mm wide, could be fed through a forming machine (consisting of at least one set of co-operating rollers) to form the metal

300 strip into a "U" shape having turned-over edges (useful for screeding) in a similar manner to those

forming machines that make copper spouting from flat copper strip material. Corrugations could be added. It would be relatively difficult to form the internal cross members that support the preferred length or lengths of reinforcing material, plus optional pipes or cables, but these may be supported on wire forms that, when dropped into the "U" shaped channel as it lies on the ground, support the inserts 305 at about 50 mm (2 inches) above the base of the channel.

8) Metal shapes for use as edging strips, having shapes like the vacuum-formed examples described above, may also be formed by pressing sheets between dies. This method has the advantage that there are standard procedures, well-known in the art, for impressing corrugations or the like into the product in order to stiffen a plain (flat-sheet) shape, so that a desired amount of stiffness can be obtained with

310 thinner, lighter, and less costly material. It would be possible to use steel or aluminium sheet of a thickness from about 0.2 (like a foil) to 1 mm or more in this application.

9) Use of corrugated plastic piping. This is currently made in PVC with a circular cross-sectional profile. The inventors prefer to adapt the overall shape of the existing material by commencing with manufacture of either a square-sectioned pipe that is cut along its length into two halves, each of which

315 resulting halves has a relatively stiff (in section) "U"-shaped profile yet is flexible along its length and may be used in the same manner as previously described edging, or to make a "U" -shaped profile in the first instance. The range of dimensions proposed are similar to those described elsewhere in this specification. One advantage of this material is that the lengthways flexibility applies to both horizontal and vertical axes and hence a user has relatively more freedom to conform to existing

320 topography as it is found, without having to plan an order for purchase. A second advantage is that the maximum sharpness of bends is inherently limited. Another is that the transverse dimensions at a bend are hardly altered at the bend, although with some other materials compression may be seen at a bend caused for reasons such as buckling of the inner radius or stretching of the outer radius. The material may be supplied in rolls of any convenient length.

325 Figs 2 to 10 show examples of single straight moulded items made according to the invention. A vacuum forming technique is preferred. In Fig 2, the base 201 (including some strengthening ridges 204) would be laid upon the ground ready to accept concrete, or laid in a shallow trench so that the resulting surface is lower and may be flush with the ground surface or below it. This example has sloping sides 202, 203. That slope is useful when shipping the product, because items may be nested

330 inside each other. The sides terminate in bent-over tops 205, 206 having mainly strengthening attributes but also of use as a rubbing surface when levelling (screeding) the poured concrete.

Periodic cross-bridges 207 cut across the interior of this example item of formwork. These do not

reach the top (in most configurations), so that the resulting concrete beam will not be fully interrupted. Nevertheless they may act as crack formers of use when the concrete shrinks. In order to maintain the

335 lengthwise continuity of the concrete, horizontally directed apertures 211 are provided under the bridges along the length of the moulded item. The bridges provide strength by preventing the side walls from diverging when filled, and they support a variety of embedded elongated structures (such as reinforcing bars of steel, water pipes, or electric cables carrying communications, mains power or low- voltage "safe" current) on top of the bridges, within the valleys 208, 209, 210. (Three valleys are

340 shown in this example). The elongated structures can be tied in place or simply placed in the valleys before pouring the concrete. An electric cable is inadequate for providing tensile strength for structural reinforcement, but a cable can be used in combination with at least one or preferably two steel reinforcing bar. The use of only low-voltage (garden lighting purposes) or residual-current-detection protected wiring is recommended in case of leakage of hazardous current from unintentional breaks.

345 Use of reinforcing bars should, within reason, give the cured concrete sufficient strength to withstand the weight of road vehicles.

The strengthening ridges 204, in combination with the base 201, the periodic cross-bridges 207 and the rounded-over lip or lips (205, 206), have the effect of rendering even a thin (originally about 1 mm thick) plastics moulded structure stiff enough that the sides will not spread laterally by more than 350 about 4 mm mid-way between cross-bridges under the sideways force exerted by a charge of wet concrete. In a manufactured example, the cross-bridges terminate about 25 mm below the upper edges of the sides. As with other kinds of formwork, the action of screeding the top surface more than necessary can result in excessive spreading force unless care is taken.

The plan view of Fig 3 shows an area between a first cross bridge 207A and a second cross bridge

355 207B, with rectangular strengthening ribs moulded into the floor 201 at 204 and walls 203 at for example 212. Apertures such as 213 are cut or otherwise formed through the floor along the length of the moulded item in order to let concrete flow or fall through the moulded structure, as previously discussed in relation to hole 104 in Fig 1. Fig 4 (which displays an item from the side, with the base

201 at the right and the top edge 205 at the left) shows (a) repeated reinforcing ribs (212) within the

360 wall, and (b) that cross bridges 207 represent partial voids across the width of the item. Holes 211 will also allow concrete to reach the space beneath the item of formwork, as do holes 213 (not shown in Fig

4.) Fig 5 is a perspective view of an entire straight unit having 11 cross bridges. Each unit is sufficiently flexible to be mated end-to-end with like units by forcing one inside another against the springy nature of the plastic, so that an edging of any specified length can be made. The lips 205, 206

365 help to retain the two units in alignment. The material can be cut as required, such as with a knife or

shears, in order to fit plans or existing structures or areas.

Fig 6 shows in perspective a bend 600 which runs through a 90 degrees arc of a circle. This is an example bend. Different radii would preferably be made and sold as such, while different arc lengths may more easily be cut on the job. Component parts of this item are as previously described in relation 370 to Figs 2-5 and the cross-bridges in particular are evident. Fig 7 shows an example sharp corner 700. This is a 45 degrees corner (elbow) and component parts of this item are as previously described in relation to Figs 2-5. Corners (elbows) having other common angles such as 30, 45, 60 and 90 degrees (or any other angles) can be moulded and stocked for sale. The angles mentioned are of course given by way of example only.

375 The Fig 8 example shows non-symmetrical edging. One side 800 is offset above and/or sideways from the axis of the moulded item by a step 801. This option may (for example) be useful when laying concrete blocks on top of the formwork, after a concrete beam has been made within the body 802 of the formwork. A sloping top surface is easily drained.

Fig 9 shows a short section 900 of a moulded edging which includes an inclined section between 901

380 and 902, for laying up or down sloping land. This example could be described as being curved about a horizontal axis, whereas Fig 6 is described as being curved about a vertical axis). Other amounts of change of orientation may be made according to the illustrated version according to the invention.

Example 900 provides for a gradual incline. A person making edging may cut the inclined section between 901 and 902 and join in straight sections of any required length, or join two inclined sections

385 together in order to have twice the deviation in slope.

It is sometimes convenient to combine a curved or elbow section with a straight section during moulding, as in the example 1000 of Fig 10. In this Example, a relatively long straight section between 1001 and 1002 is moulded and provided with a 90 degrees corner on one end, finishing in an open end at 1003. This shape is inherently asymmetrical and should be made in left-hand and right-hand

390 versions. Although we have shown one specific example, curved or elbow section of any angle of deviation as previously described. Mirror images are also provided because of the asymmetry involved. It would be possible to construct an edging around a small flower garden with two bent sections as shown in Fig 10, and perhaps two straight sections, or more, depending on the actual dimensions. "T" or "X" junctions can be moulded in a similar way (see Figs 14:1400 and

395 15:1500)and might be made of a stronger grade of material in order to cope with extra strain during construction.

EXAMPLE 3

An alternative plastics material is similar to a known, moulded flexible drainage pipe made of a black- 400 coloured polyethylene or polyvinyl chloride plastics material, of circular cross-section and in particular having a corrugated or bellows-like wall along substantially the entire length. One example is sold in New Zealand under the brand "NOVAPLOW". This material comprises a series of circular rings (or a continuous spiral) all joined sideways to each other. The resulting pipe is relatively flexible, like a bellows, along its length although surprisingly rigid under transverse compression and is widely 405 used after burial in shallow trenches for the drainage of soil. The pipe is provided with a plurality of slits in the wall for the admittance of surplus ground water. It is not made in a rectangular cross- section.

Example 3 retains the concept of the circumferential corrugations, while adapting the overall shape of the existing material into a "U" shape as shown at 1200 in Fig 12a. According to the invention, either a

410 square-sectioned pipe is made and then cut alongth into two halves, each of which has a relatively stiff (in section) "U" -shaped profile yet is flexible along its length and may be used in the same manner as previously described edging, except that this version allows curves and inclines to be made as and when required, rather than relying on supplied pre-formed curves. Alternatively a "U" -shaped profile with edges is made such as by the vacuum forming process that was described earlier. An insert 1204

415 (also drawn separately in the top part of Fig 12b) may be wedged into the space where a wider portion of the pipe exists as shown within the plan view at 1204, in order to carry reinforcing material, pipes or cables within the depressions 1205 formed within the top section. Two depressions for locating those inclusions are shown along the upper surface of the insert; from 1 to 6 or more may be used. Aperture 1206 admits concrete (as previously described) in order to maintain the lengthwise integrity

420 of the reinforced concrete beam. A plan view of some straight edging according to this aspect of the invention is shown at 1208. Here, some elongated holes 1209 have been cut into the base of the "U" section in order to let poured concrete access the ground below. The range of dimensions proposed are similar to those described elsewhere in this specification. One advantage of this material is that the lengthways flexibility applies to both horizontal and vertical axes and hence a user has rather more

425 freedom to conform to existing topography. A second advantage is that the maximum sharpness of bends is inherently limited. A further advantage is that the transverse dimensions at a bend are hardly altered at the bend, in contrast to some other materials where compression may be seen at a bend caused for reasons such as buckling of the inner radius or stretching of the outer radius. On the other hand this flexibility may mean that the material will not remain where it is placed particularly if it is

430 not placed in a shallow trench, and a support peg 1100 as described more fully in the following section

may be used to hold the material in place until it is filled with wet concrete. This support peg is shown as dashed lines in Fig 12b, and a two-spike version is illustrated. The slight outward slope of the "U" section allows this material to be packed relatively tightly by either stacking short lengths on top of each other, or by coiling a long length on to a reel. If short sections are used they may interlock with 435 each other when forming end-to-end joins.

EXAMPLE 4

In an alternative version of this invention, as shown in Fig 11, the invention provides a series of reusable shutters 1101, 1102 to be placed along a garden edging, to hold the concrete in place while it sets. The shutters are clipped or placed within the vertical projections 1109 each of a series of

440 preferably injection-moulded sacrificial support pegs 1100 that are also used in this version. Each peg such as 1100, 1100' and 1100" is pushed into the ground at a spacing of perhaps 1 foot (25.4 cm) apart along the track of the edging. The pegs as drawn have one spike 1103 that penetrates the soil. More than one spike 1103 would prevent inadvertent turning. Each peg includes shutter retention means - preferably at least two. In this example a ridged section 1104 engages with corresponding ridges 1105

445 along each shutter, although the ridges 1105 (if used at all) should not be so large that they lock into the hardened concrete. Each shutter may be made for example of pressed and folded metal, plastic or wood. It is intended that the shutters can be removed and re-used. In one version the shutters are short (like shutter 1102) and the shutters can be joined end to end either inside the pegs or between them. In another version (as indicated in 1101) the shutters are relatively long. The top edge of the shutters may

450 be folded over as shown at 1106 in order to provide both stiffness (absent from prior-art formwork of this type) and a surface on which a screeding edge can be supported when the concrete is being finished, or the folded over portion may be deleted so that the shutter can be bent around a vertical axis. The pegs are preferably made to also include support means 1107 for reinforcing bars 1108 as shown in the pegs 1100' and 1100". In one option the support means 1107 can be broken off if desired.

455 EXAMPLE 5

Fig 16 shows yet another option. In this option a series of "U"-shaped units are made. Each includes one ventral aperture 213 through a base 1601, one cross-bridge 207, and two joining sides 1603 which fit into side slits 1604 to varying depths thereby giving an assembly of such units the ability to comprise straight or curved edging as shown in the plan view of the assembly.

460

EXAMPLE 6

Finished concrete edging may include a longitudinally trowelled or rolled or otherwise formed channel within the top of the concrete surface so that water can be carried along the edging. Fig 13a shows a useful accessory; a hand-held roller 1300 useful for forming a shallow groove or channel in the upper

465 surface of the wet concrete so that the channel serves to carry any water along the line of the edging towards a lower point. The channel-forming roller includes a handle 1301, a frame 1304, and a straight section of a roller 1302 surmounted by a projecting curved section 1303. Preferably the roller is either made of, or is coated with a plastics material to which concrete (or mortar) does not stick, so that a good finish is easily obtained. A suitable plastics material is polyteterafluorethane (Teflon(R)). For

470 simplicity, a paint roller handle could used with a compatible roller according to the shape of roller 1302. The form of roller 1305 shown in Fig 13b is useful for laying a patterned finish on a wet concrete surface after screeding and perhaps trowelling. The transverse grooves made by projection 1306 may be used as shrinkage crack initiators or for helping mortar to adhere to the upper surface of the concrete.

475 VARIATIONS

Other plastics materials, wood, or cardboard may be used for the structures, and could be made from several lengths joined together or could even be milled from solid beams as per the existing method for making mouldings from timber. Biodegradable material, such as material developed from corn or wheat or potato starch, or cellulose such as papier mache may be used. The price of plastics obtained 480 from the petrochemical industry may rise substantially. If degradable materials are used, the beam will shift or settle slightly while the supporting material becomes degraded and disappears.

The invention can be used along a fence line to impose a "no-grow" strip for example, and the channel units can be dropped down over, or clipped around the fence posts so that they are aligned along the fence line. This is useful on farms, to reduce the chance of an electric fence being shorted out by grass 485 growing beneath). Other applications will be evident to a farmer, landscaper, or gardener.

INDUSTRIAL APPLICABILITY and ADVANTAGES

The invention provides a well-controlled, permanent form for a concrete edging as used in a garden, landscape, park or playground and the result is reasonably permanent, especially if reinforced.

The invention is relatively plant-impervious (unlike a row of bricks for example), useful if invasive 490 plants /weeds or the like are spreading in the lawn and are to be excluded from a garden.

The ability to include reinforcing iron for added strength is an advantage over the prior art. Cracked and broken concrete edging, commonly seen after extruded type edgings have been in place for a time, looks bad and is not easy to replace. The present invention should be able to withstand the weight of a vehicle tyre if properly reinforced.

495 The invention can be used for limited reticulation of water, communications, or electric power. Such items are then protected from inadvertent damage by soil cultivation or diggers.

There is no requirement for a haunching form of construction in which the uppermost surface is supported on sloping sides of concrete; a procedure that consumes much more concrete than the present invention. According to the present invention, about 200 lineal feet of edging can be obtained 500 from a cubic yard of concrete, or about 80 lineal metres from a cubic metre of concrete.

The materal that is sold (the formwork itself) is light in weight and easily packed for travel as lightweight nested stacks, perhaps with accompanying accessories, while the heavy components (the concrete or mortar) may be obtained locally.

The layout of the edging can be reviewed in situ after placement by the site owner but before any 505 concrete is poured or steel is placed, which is useful when the job has to satisfy aesthetic requirements.

Finally, it will be understood that the scope of this invention as described and/or illustrated herein is not limited to the example embodiments. Those of skill will appreciate that various modifications, additions, known equivalents, and substitutions are possible without departing from the scope and spirit of the invention as set forth in the following claims.