WO2004048720A2

WO2004048720A2 - A fence, a method of constructing a fence, a structural fence element and a method of making a structural fence element

Info

Publication number: WO2004048720A2
Application number: PCT/IB2003/005493
Authority: WO
Inventors: Shamiel Abrahams
Original assignee: Shamiel Abrahams
Priority date: 2002-11-28
Filing date: 2003-11-28
Publication date: 2004-06-10
Also published as: EP1565631A2; WO2004048720A3; AU2003283645A1

Abstract

The invention relates to a fence (10) including upstanding posts (12) top, mid and bottom rails (16,70,14), extending between the posts (12) and an infill in the form of upstanding elements (20) or a wire mesh (62) extending between the rails (14,16,70) and/or the posts (12). A plurality of spikes (18) extend generally upwardly from the rails (14,16,70). A structural fence element (210) is also provided which includes a slab (212) or coping (228) of concrete or plastic, in which a protrusion (216) is embedded in part, with a sharp edge (218) of the protrusion (216) extending generally upwardly from the slab (212) or coping (228). The invention extends to methods of making the fence (10) and structural fence element (210).

Description

A FENCE. A METHOD OF CONSTRUCTING A FENCE. A STRUCTURAL FENCE ELEMENT AND A METHOD OF MAKING A STRUCTURAL FENCE

ELEMENT

FIELD OF THE INVENTION

THIS INVENTION relates to fencing. In particular, it relates to security fencing for the perimeter of property.

BACKGROUND TO THE INVENTION

The installation of spikes or razor formations on fences such as perimeter fences, to deter intruders, can be done by fixing an attachment including the required spike or razor formations, to an upper edge of the fence, e.g. by affixing the attachment by way of fasteners, such as screws or nails, driven into the fence. These attachments can be pried off the fence by use of a simple object, such as a screw driver, steel bar, or the like. The method of installing the attachment is cumbersome, labour intensive and requires a number of tools which often have to be powered, e.g. electrically powered, pneumatically powered, etc. The structural integrity of the fence is also often compromised by the fasteners used in this method of attachment.

Fences can be constructed with upright elements extending upwardly from the fences, which define sharpened ends or spikes. However, these elements have to be held in position by generally horizontally extending elements, and intruders can often use these elements as steps or can use a ladder, to climb over the fences, while supporting themselves on the horizontal elements to clear the spiked elements. This type of construction also requires welding to be done in situ, when erecting the fence, and the welding operation requires welding equipment to be provided in the location where the fence is erected, which could be remote from a supply of electricity. The welding also damages anticorrosive coatings on metal structural elements, adjacent the weld, creating a need to protect these areas against corrosion.

Electrical conductors are often installed on fences, to inhibit intrusion of property over the fences, and these conductors are typically supported by brackets attached to a top of a fence. However, the attachment of brackets to fences suffers the same weaknesses mentioned hereinabove in relation to spikes attached to fences after construction.

SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided a method of constructing a fence, said method including: erecting two or more spaced, upstanding posts; attaching a bottom rail to at least one pair of adjacent posts to extend between the posts; attaching a top rail to the pair of adjacent posts, in a spaced arrangement above the bottom rail, to extend between the posts, said top rail and/or said bottom rail defining a plurality of upstanding spikes extending generally upwardly; and attaching an infill to the bottom rail and the top rail to extend between the bottom rail and the top rail, and/or to the pair of adjacent posts to extend between the posts.

The term "infill" means any material used to span between the rails and/or posts of the fence. The term "generally upwardly" include all upwardly directions, whether vertical or at an angle and, in relation to spikes, it therefore includes spikes extending upwardly at an angle, towards a front, rear or side of a fence.

The infill may be a wire mesh that may be attached to the top rail and bottom rail. The infill may, for example, be attached to a rail of the fence by: receiving a part of the infill, such as a wire of the mesh proximate an edge of the mesh, in a vertex of a resilient V-shaped clip; resiliently pressing the legs of the clip towards each other to narrow the V-shape of the clip; inserting the legs of the clip through an aperture defined in the rail, to protrude through the aperture on a side of the rail, opposite from the infill; and releasing the legs, allowing the V-shaped clip to expand resiliently and abut the periphery of the aperture.

The V-shaped clip may be attached to the rail by receiving protuberances extending inwardly from a periphery of the aperture, in recesses defined in the legs of the clip.

The infill may include spaced, upstanding elements such as tubes, bars, angle irons, or the like, which may be attached to the top and bottom rails, e.g. by clipping-on or welding. The upstanding elements may be passed through apertures in the top and bottom rails, each having a shape complemental to the cross-sectional profile of the upstanding elements.

The method may include the step of attaching one or more midrails to a pair of adjacent posts, to extend between the posts in a spaced arrangement between the bottom rail and the top rail. Each bottom rail and/or midrail may define a plurality of upstanding spikes, extending generally upwardly.

The top, bottom and midrail may be attached to a post at an angle, to allow the rails to follow the profile of a landscape on which the fence is constructed, e.g. by pivotally attaching each rail to the post, pivoting the rail into a required position, and fastening the rail to the post. The method may include the further step of attaching an electrical conductor in an insulated fashion, to at least some of the spikes, or to the posts. Instead, the method may include the further steps of insulating at least one of the rails from the fence, and electrifying the insulated rail.

According to another aspect of the invention, there is provided an accessory for a perimeter fence or fence, said accessory including: an elongate, planar fixing flange, for attachment to the fence or fence; and at least one elongate, planar spiked flange, generally perpendicularly extending from at least one edge of the fixing flange, and defining a spiked profile on an edge of at least one spiked flange, opposite from the fixing flange.

The accessory may include a rear flange extending generally parallel with the spiked flange, and being attached to a second edge of the fixing flange, and may further include a top flange extending generally parallel with the fixing flange, between the spiked flange and an upper edge of the rear flange.

The accessory may include attachment formations extending from longitudinally spaced ends of the accessory, such as longitudinally extending protuberances defining apertures in which elongate fasteners such as bolts, are receivable. The accessory may be integrally formed and may be of a metal, such as carbon steel, e.g. mild steel, stainless steel, etc.

Apertures may be defined in spikes of the spiked flange, through which an electrical conductor can pass, preferably while being electrically insulated from the spiked flange.

According to a further aspect of the invention, there is provided a fence which includes: at least two spaced, upstanding posts; a bottom rail extending between at least two adjacent posts; a top rail extending between the adjacent posts in a spaced arrangement above a bottom rail, and defining a plurality of upstanding spikes, extending generally upwardly from the fence; and an infill extending between the bottom rail and top rail, or extending between the adjacent posts.

The fence may further include one or more midrails extending between the adjacent posts in an arrangement spaced from the top and bottom rails. Upstanding spikes may be defined on the bottom rail and/or on the midrail, extending generally upwardly. The infill may be a wire mesh attached to the rails by resilient clips as described hereinabove, or may include upstanding elongate elements welded to the top, mid, and/or bottom rails. The upstanding elongate elements may have smooth longitudinal edges, or serrated edges and/or may include spikes.

Apertures may be defined in each rail for attachment of an infill to the rail. The apertures may include protuberances extending inwardly from a periphery of the aperture, to receive a resilient clip formation as described hereinabove and/or the apertures may be complemental in shape to a cross- sectional profile of elongate elements of the infill, allowing the elongate elements to pass through the complemental apertures.

Each post may define a lateral recess in which an end of a top, mid, and/or bottom rail is receivable or in which an attachment formation disposed at such an end of a rail is receivable. Each post and each rail may include pivotal attachment means, for pivotally attaching the rail to the post, such as apertures defined adjacent each lateral recess, and apertures defined proximate an end of each rail, so that the end of the rail can be inserted into the longitudinal recess, the apertures can be brought into register, and an elongate fastener such as a bolt can be passed through the apertures, allowing the rail to pivot about the fastener. Each of the top, mid, and/or bottom rails may be an accessory for a perimeter fence or fence, as described hereinabove.

The fence may include support formations for receiving and supporting at least one electrical conductor, spaced above the fence. The support formations may include the spikes extending from upper ends of at least two of the posts, or spikes extending generally upwardly from the rails of the fence. The support formations may define apertures for receiving insulating attachment formations to which the conductor can be attached, while being electrically insulated from the fence.

The infills of the fence may be electrically insulated form the posts and/or rails, and may be electrified.

The invention extends to a fence, or part of a fence comprising laterally spaced posts, rails extending between the posts, and an infill extending between the rails and/or the posts, substantially as described hereinabove, but are moveable, to serve as a gate.

According to yet a further aspect of the invention there is provided a structural fence element which includes: a body of cast material, such as a concrete and/or plastic casting; and a protrusion, partly embedded in the body, and defining a sharp edge, protruding from one side of the body. The protrusion may be of a metal or plastics material.

The body may be a slab, configured to be receivable in lateral slots, defined in spaced, upstanding posts, by sliding the slab into position along the slots. The element may have a rectangular shape with a length which permits it to be slid into slots which are typically spaced about 1,45 metres apart, and the protrusion may be disposed on side of the slab forming an edge, so that it can protrude generally upwardly from the edge of the slab, when the slab is received in the slots.

Instead, the body may be in the form of a coping defining a fence engagement face for attachment on top of a fence, e.g. by attaching it with cement on top of a masonry brick fence, and the protrusion may be disposed on a side of the coping opposite from the fence engagement face, so that it will protrude upwardly from the coping, when installed on top of a fence. The coping typically has a length of about 1m.

Instead, the casting may be in the form of a cast palisade fence- element.

The protrusion may have a variety profiles, protuberances orientated at an angle, etc., and may be serrated, spiked, or have a profiled edge. The protrusion may extend along the length of the body, and may extend beyond one end of the body and end short of the opposite end of the body, or may extend beyond both ends of the body.

The element may include attachment formations for attaching it to another element in an end-to-end arrangement. Each attachment formation may be in the form of an aperture defined close to one end of the protrusion, which allows protrusions of adjacent elements to be attached to one another, e.g. by bolting or welding.

The protrusion may be disposed along a centre of the side of the casting, and the side of the casting may be bevelled on both sides of the protrusion, may have a half-round profile or a rectangular profile, may be disposed at an angle, etc.

According to yet a further aspect of the invention, there is provided a method of making a structural fence element as described hereinabove, said method including the steps of: providing a mould for making a concrete and/or plastic casting, the mould defining a cavity having the required shape of the casting; positioning an article defining a sharp edge, along one side of the mould, so that a part of the article extends into the cavity; casting a castable material such as concrete and/or plastics material, into the cavity; and allowing the concrete and/or plastics material to solidify, e.g. to cure or settle, so that the article becomes a protrusion, partly embedded in the concrete/plastics material, with its sharp edge protruding from the casting.

The method may include an additional step of vibrating the mould before the cast material solidifies, e.g. before the concrete is cured.

The method may include the further step of installing the structural fence element as described hereinabove in a fence, with the sharp edge of the protrusion protruding generally upwardly from the structural fence element.

The structural fence element may be installed by sliding it into position along lateral slots defined in two spaced, upstanding posts. This may require the removal of a structural element which previously occupied the position in which the structural element according to the invention, is to be installed, and/or may include receiving the structural fence element on top of an existing fence element.

Instead, the structural fence element may be installed by attaching it to the top of a fence, such as a masonry fence, e.g. with cement. The invention extends further to a fence including a structural element as described hereinabove. The structural fence element may be electrified, e.g. by conducting electric pulses through the metal protrusion. Instead, the protrusion may include means for supporting an electrical conductor, e.g. by way of apertures defined in the protrusion through which the conductor may extend, brackets extending from the protrusion to which the conductor may be attached, provision on the protrusion for attaching such brackets, or the like.

In the event that a conductor is supported on a protrusion which itself is a conducting material, the supporting means may be of an electrically insulating material, to insulate the conductor from the protrusion, e.g. by way of insulating grommets disposed inside apertures through which the conductor extends.

The invention will now be described, by way of non-limiting example, with reference to the accompanying diagrammatic drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings: Figure 1 shows a front elevational view of part of a fence in accordance with a first embodiment of the invention; Figure 2A, 2B and 2C show three-dimensional views of three separate versions of an accessory for a perimeter fence in accordance with a second embodiment of the invention;

Figure 3 shows a three-dimensional view of part of one version of a post for use in the fence of Figure 1 ;

Figure 4 shows a side elevational view of part of a post in accordance with a third embodiment of the invention, which is similar to a top plan view of the accessory of Figure 2;

Figure 5 shows a top plan view of the post of Figure 3;

Figure 6 shows a top plan view of a rail in accordance with a fourth embodiment the invention;

Figure 7 shows a sectional side view of the rail of Figure 6, taken at VII-VII;

Figures 8A and 8B show a front elevational view and a side elevational view, respectively, of a V-shaped clip in accordance with a fifth embodiment of the invention;

Figures 9A, 9B and 9C show front elevational views of three versions of insulating, non-conductive spiked accessories for use in the fence of Figure 1 ;

Figures 10A and 10B show a front elevational view and sectional side view, respectively, of a further version of the fence of Figure 1, including upstanding elements;

Figures 11A and 11B show front elevational views of further versions of the fence of Figure 1 , including wire mesh infills; Figure 12 shows a front elevational view of a gate in accordance with a sixth embodiment of the invention;

Figure 13 shows a front elevation view of a fence in accordance with a seventh embodiment of the invention;

Figure 14 shows a top plan view of the fence of Figure 13;

Figure 15 shows a sectional side view of a post of the fence of Figure 13 taken at XV-XV;

Figure 16 shows a sectional side view of a post of the fence of Figure 14 taken at XVI-XVI;

Figure 17 shows a detailed top plan view of a part of the fence of Figure 14;

Figure 18 shows a detailed front elevational view of the part of the fence of Figure 17;

Figure 19 shows a side elevational view of a part of a post of the fence of Figure 13;

Figure 20 shows a top plan view of the part of the post of Figure 19;

Figure 21 shows a front elevational view of the part of the post of Figure 19;

Figure 22 shows a top plan view of a post in accordance with an eighth embodiment of the invention;

Figure 23 shows a side elevational view of an infill attachment in accordance with a ninth embodiment of the invention;

Figure 24 shows an end view of the infill attachment of Figure 23; Figure 25 shows a front elevational view of an accessory in accordance with a tenth embodiment of the invention;

Figure 26 shows a side elevational view of the accessory of Figure 25;

Figure 27 shows a three-dimensional view of an accessory in accordance with an eleventh embodiment of the invention;

Figure 28 shows an exploded three-dimensional view of part of a post in accordance with a twelfth embodiment of the invention;

Figure 29 shows a side elevational assembled view of part of the post of Figure 28;

Figures 30A and 30B show three-dimensional views of part of a post in accordance with a thirteenth embodiment of the invention;

Figure 31 shows a top plan view of the posts of Figure 30;

Figure 32 shows a three-dimensional fragmental view of a structural fence element in accordance with a fourteenth embodiment of the invention;

Figure 33 shows a front elevational view of another version of the element of Figure 32;

Figure 34 shows a side elevational view of the element of Figure 33;

Figure 35 shows a fragmental front elevational view of a structural fence element in accordance with a fifteenth embodiment the invention;

Figure 36 shows a front elevational view of a structural fence element in accordance with a sixteenth embodiment of the invention;

Figure 37 shows a side elevational view of the element of Figure 36;

Figure 38 shows a side elevation view of a structural fence element in accordance with a seventeenth embodiment of the invention; and Figure 39 shows a front fragmental view of an installation of structural fence elements of Figure 38.

DETAIL DESCRIPTION OF THE DRAWINGS

Referring to the drawings, a fence in accordance with the invention is generally indicated by reference numeral 10.

Referring to Figure 1 of the drawings, a fence 10 in accordance with the first embodiment of the invention includes a plurality of upright posts 12 with a bottom rail 14 extending between adjacent posts close to ground (not shown) above which the fence is to be erected and a top rail 16 extending between the posts in a spaced position above the bottom rail 14 and including spikes 18 extending generally upwardly from the top rail. The fence 10 includes an infill in the form of upstanding elements 20 extending between the bottom rail 14 and top rail 16. The upstanding elements can have smooth longitudinal edges, or serrated edges, or can include spikes 21. Each rail 14,16 can be attached to each post 12 by way of an elongate fastener in the form of a bolt 22. A non-conductive or insulated extension 24 is provided at the top of the post 12 and includes means to support electrical conductors in the form of wires 26 in a spaced relation above the top rail 16.

Spikes 18 can also extend in other directions, e.g. extending to sides, a front or rear of the fence 10. The top rail 16 can be electrically insulated with non-conductive material, and may be electrified, to serve as an additional deterrent to would- be trespassers.

Referring to Figures 2A, 2B and 2C of the drawings, an accessory 28 in accordance with the second embodiment of the invention is shown. Each accessory 28 includes an elongate, planar fixing flange 30, and an elongate, planar spiked flange 32, generally perpendicularly extending from a front edge 34 of the fixing flange. A number of spikes 18 are defined on an upper edge of the spiked flange 32. The versions of the accessory 28 shown in Figures 2B and 2C, each include a rear flange 36 extending generally parallel with the spiked flange 32 while being attached to a rear edge 38 of the fixing flange 30.

The version of the accessory 28 shown in Figure 2B of the drawings, includes attachment formations in the form of longitudinally extending protuberances or tongues 40, extending from longitudinally spaced ends of the accessory and defining apertures 42 in which elongate fasteners such as bolts, are receivable.

The version of the accessory 28 shown in Figure 2C of the drawings, includes a top flange 60 extending generally parallel to the fixing flange 30. The spikes 18 are formed from the same plate as the top flange 60.

Referring to Figures 3 to 5 of the drawings, a post 12 in accordance with the first and third embodiments of the invention has a generally elongate shape and a generally square cross-section. The post 12 defines recesses 44 in its side, in which an end of a rail 14,16 or accessory 28, or a tongue 40, is receivable. An aperture 46 is defined adjacent the recess 44 so that a wire end of a wire mesh infill (see below) can extend through the aperture 46. It is to be understood that a number of recesses 44 and apertures 46 can be defined along the length of the post 12.

Apertures 48 are defined on each post 12, and are complemental in shape to the cross-sectional profiles of elongate metal elements, to be attached to the post 12, or are configured to receive a clip for attaching a wire mesh infill to the post. A number of variations of apertures 48 are illustrated in Figure 4 of the drawings, although only one variation will typically be used on a post 12.

Referring to Figures 6 and 7 of the drawings, apertures 48, similar to the apertures 48 on the posts 12, are defined in a rail 14,16 or in a fixing flange 30 of an accessory 28. An aperture 48 having the shape shown by reference numeral 48.1, is configured to receive an end of an elongate metal element with a rectangular cross sectional profile. Protuberances 52 extend inwardly from a periphery of the aperture 48.1 and can be bent upwardly as shown in Figure 7 of the drawings.

Referring to Figures 8A and 8B of the drawings, an infill such as a wire mesh can be attached to a rail 14,16, a post 12, or an accessory 28, by receiving a metal wire of the mesh, proximate an edge of the mesh, in the vertex 58 of the clip 50, pressing the legs 56 resiliently towards each other, to narrow the V-shape of the clip, inserting the legs into an aperture 48 and releasing the legs so that the clip expands resiliently and abuts the periphery of the aperture 48.

The versions of the accessories 28 shown in Figures 2 and 9 of the drawings may be substituted for a rail 14,16 in the fence 10.

Referring to Figures 9A, 9B and 9C of the drawings, three versions of spiked accessories 64 are shown. The spiked accessories 64 can be attached to a post 12 or top rail 16 of a fence 10 in accordance with the invention, to extend generally upwardly and can serve as an obstruction or deterrent to would-be trespassers, can serve an aesthetic function, or can serve to support an electrical conductor such as a wire 26 above the fence 10.

The spiked accessory shown in Figure 9C can be built into a conventional masonry fence, or can be cast into a prefabricated fence element, so that it is part-embedded in the fence or fence element, to serve the same purpose as the accessories shown in Figures 9A and 9B.

Referring to Figures 10A and 10B of the drawings, a front elevational view of a version of the fence 10 in accordance with the first embodiment of the invention, shown in Figure 1 of the drawings, is shown in Figure 10A, while Figure 10B shows a sectional side view of the fence of Figure 10A, taken at B-B. Vertical elongate elements 20 extend between the bottom rail 14 and top rail 16 in the fence 10, while some of the spikes 18 of the fence are longer than adjacent spikes, and include means for supporting a wire 26, spaced above the top rail 16.

Referring to Figures 11A and 11 B of the drawings, front elevational views of two further versions of the fence 10 in accordance with the first embodiment of the invention, are shown. Wire meshes 62 extends between the bottom rail 14 and top rail 16 in each of the fences 10 and are attached to the rails 14,16 by way of resilient V-shaped clips 50 (not shown), as described hereinabove. Alternatively, the wire meshes 62 can be attached to the rails 14,16 by spot welding wire ends of each mesh to the rails, or by passing the wire ends through apertures, such as the aperture 46 shown in Figure 3 of the drawings. The wire ends can be secured in position by twisting, bending, flattening, etc. its ends on the side of the aperture, opposite from the mesh. A spiked accessory 64 as shown in Figure 9A of the drawings is attached on top of a post 12 in the version shown in Figure 11A, and supports two wires 26 spaced above the top rail 16. Spiked accessories 64 as shown in Figure 9B of the drawings, have been attached to the top rails 16 of the version shown in Figure 11 B, by welding, glueing, or clipping-on the spiked accessories to the top rail. The spiked accessory 64 in the version of the fence shown in Figure 11 B of the drawings, supports a wire 26, spaced above the top rail 16.

Referring to Figure 12 of the drawings, a front elevational view of a gate 66 in accordance with a sixth embodiment of the invention, is shown. The gate 66 includes two spaced upright posts 12, a bottom rail 14 and top rail 16 extending between the posts 12 and upstanding elements 20 extending between the rails 14,16. The gate 66 further includes rollers 68 which are partly recesses within a bottom of the bottom rail 14, on which the gate can be rolled. A midrail 70 extends between the posts 12 generally parallel to the bottom rail 14 and top rail 16, and is spaced therefrom. Spikes 18 are provided on each of the bottom rail 14, midrail 70 and top rail 16. Pedestrian gates and safety gates can also be made with the same general construction as the gate 66.

It is to be appreciated that the general structure of each of the rails 14,16,70 is generally similar, and that any version of a fence 10 or gate 66 may include any number of spiked rails extending between adjacent posts 12.

All the components of a fence 10, accessory 28 or gate 66 are generally made from carbon steel, e.g. mild steel, stainless steel, etc., and are protected against corrosion by galvanising and/or painting, but the components may be made from any suitably strong material. The conductors 26 should preferably be isolated from the fence 10 or gate 66 and this is typically achieved by supporting the conductors on spikes 18 or spiked accessories 64 made from a non-conducting material, or by electrically isolating the conductor from the spikes or spiked accessory by way of nonconducting attachment formations (not shown).

In use, a fence 10 in accordance with the first six embodiments of the invention is constructed by erecting a plurality of spaced upright posts 12 and by attaching a bottom rail 14 and a top rail 16 between at least two adjacent posts by way of bolting, as described hereinabove. The rails 14,16 are pivoted to an orientation relative to the post 12, which allows it to follow the profile or surface of the ground on which the fence 10 is being erected, and are secured in position by tightening the bolts 22. One or more midrails 70 may be attached in similar fashion, between the bottom rail 14 and top rail 16. In addition to bolting, the rails 14,16,70 may be welded to the posts 12. An infill in the form of upstanding elements 20 is attached to the rails 14,16,70 to span between the bottom rail 14 and top rail 16, or similar elements (not shown) are attached to the posts 12, to span between the posts. The elements 20 are attached to the rails 14,16,70 or to the posts 12 by inserting the elements into the apertures 48 defined in the rail or the post, and welding the elements to the rails or to the posts.

Alternatively, a filling in the form of a wire mesh 62 is attached to the rails 14,16,70 and/or the posts 12 by way of V-shaped clips 50, by receiving wires from the mesh 62 in the vertices 58 of the V-shapes, and inserting legs 56 of the clips into apertures 48 defined in the rails and/or posts, as described hereinabove.

A gate 66 in accordance with the invention is constructed in the same way.

An accessory 28 in accordance with the invention may be attached on top of a fence in the form of a masonry fence by building it into the fence in part, so that the spikes 18 protrude from a top of the fence, or may be attached to a top of the fence by nailing, bolting, etc. the fixing flange 30 to the top of a fence.

Referring to Figures 13 to 18 of the drawings, a fence 10.1 in accordance with the seventh embodiment of the invention includes upstanding posts 12.1 with bottom rails 14 and top rails 16 extending between the posts. An infill extends between the bottom rail 14 and top rail 16 and two versions of infills are illustrated, viz. a plurality of upstanding profiled elongate metal elements 80, such as hollow or channelled elements, each with a square or channel cross section, and a plurality of round bars 82. It is to be understood that a fence 10.1 will typically include only one type of infill.

The elongate elements are attached to the rails 14,16 by being aligned with apertures 84 defined in the rails, which have resilient tabs 86 extending inwardly from peripheries of the apertures 84. Once a hollow elongate element 80 is aligned with an aperture 84, the tabs 86 extend into recesses or apertures (not shown) defined laterally in the elongate element.

The round bars 82 are attached to the rails 14,16 and to the posts 12.1 by being received in dimpled apertures 88 defined in the rails 14,16 and posts 12.1 , and are flattened on sides of the apertures 88, opposite from the infill. Detail of attachment of a round bar 82 to a rail 14,16, or post 12.1 is shown in Figures 23 and 24 of the drawings. The end of each round bar 82 is flattened to form a flat head 90 which is too wide to be withdrawn through the aperture 88, and which nests in the dimple surrounding the aperture. Referring to Figures 19 to 21 of the drawings, a post 12.1 can be manufactured by connecting two complementary halves 92 together. Receiving formations in the form of recesses 46 and dimpled apertures 88 are defined on the half 92, as described hereinabove. Each half 92 includes a number of post joiner clips 94, and a number of complementary apertures 96, so that two halves 92 can be connected together in a back-to-back arrangement, by receiving the clips 94 in the apertures 96 of each other.

In use, a bottom rail 14, a top rail 16, infill, and two post halves 92 facing the infill, are connected together to form a fence sub-assembly. A fence is erected by attaching a number of fence sub-assemblies together by connected the post halves 92 together as described hereinabove. Lower ends of the post halves 92 are concreted into the ground, to prevent displacement of the post halves 92 relative to each other.

A number of post joiner clips 94 and apertures 96 are defined along each post half 92, so that halves can be connected together in a longitudinally displaced arrangement, allowing sub-assemblies to be connected together in a staggered, or stepped arrangement, with each sub- assembly at a level orientation, but at a different elevation from the adjacent sub-assembly. This type of fence 10.1 can thus follow the surface profile of a landscape on which it is erected. Referring to Figures 5 and 22, further methods are shown of connecting post halves 92 together, to form a post 12. Figure 5 shows bolting together of flanges 98, by way of a shear or snap-off bolt and nut 100. Figure 22 shows two post halves 92, connected together by mating complementary attachment formations 102, and sliding the halves together.

Referring to Figures 25 and 26, an accessory 28.1 in accordance with the tenth embodiment of the invention is shown, in use. The accessory is attached on top of a fence (not shown) by way of fasteners in the form of nails 104 extending through the fixing flange 30 and into the fence. A wire 26 is attached to spikes 18 of the spiked flange 32 by way of insulating grommets 106 connected to the wire and extending through apertures defined in each spike, so that the wire is electrically insulated from the accessory 28.1.

Referring to Figure 27 of the drawings, an accessory 108 in accordance with an eleventh embodiment of the invention is shown. The accessory 108 includes a base 110 made from an insulating material, and an upstanding flange 112 made from a conducting material and defining spikes 18 in its upper periphery. In use, the accessory 108 is attachable to a top of a fence (not shown) by way of fasteners in the form of nails (not shown) extending through the base 110 and into a top of the fence. The flange 112 is held in position by the base 110, and is electrically insulated from the fence, so that an electrical current can be passed through the flange 112. Two longitudinal passages 109 are defined in the base 110, for carrying electrical conductors, associated with electrification of the flange 112.

Referring to Figures 28 and 29 of the drawings, a post 12.2 in accordance with a twelfth embodiment of the invention, includes an outer element 114 and an inner element 116, each of channel cross section. The elements 114,116 are dimensioned so that the inner element 116 is receivable within the channel of the outer element 114. L-shaped slots 118 are defined in the lateral flanges of the channel shaped elements 114,116, so that a wire 120, such as a wire near an edge of a wire mesh 62, can slide along the L-shaped slot 118.

In use, the post 12.2 is formed and the wire 120 is attached to the post by slotting the wire into the groove 118 defined on the inner member 116, orientating the outer member 114 relative to the inner member 116 so that the L-shaped of its slot 118 extends in a direction opposing that of the inner member, and moving the outer member relative to the inner member and wire so that the wire slides along the groove 118 of the outer member 114, until the wire is held captive in the end of both of the grooves, as shown in Figure 28 of the drawings.

Referring to Figures 30A, 30B, and 31 of the drawings, wires 120 and 122 of a wire mesh 62 can be attached to a receiving member 124, by being received in L-shaped slots 118 defined in the receiving member, in similar fashion to the description with reference to Figures 28 and 29 of the drawings. The wires 120,122 are held captive within the slots 118 by attaching a cover element 126 to the receiving member 124, by way of protuberances 128, that are receivable in complementary slots 130, defined in the receiving member.

Referring to Figures 32 to 39 of the drawings, a structural fence element in accordance with the fourteenth, fifteenth, sixteenth, and seventeenth embodiments of the invention is generally indicated by reference numeral 210.

Referring to Figures 32 to 33 of the drawings, the element 210 includes a body or casting in the form of a rectangular concrete slab 212 defining a longitudinal recess 214 along its bottom edge, and a metal protrusion 216, partly embedded in a top edge of the slab 212 and having a sharp edge 218 protruding from the top edge of the slab. The protrusion 216 is centrally disposed on the upper edge of the slab 212, and bevelled surfaces 220 are defined on both sides of the protrusion.

The edge 218 shown in Figure 32 has a serrated, or waved profile, but may instead have a jaggered profile defining upwardly protruding spikes as shown in Figure 33, or the like. In the fourteenth embodiment of the invention shown in Figures 32 to 34 of the drawings, the protrusion 216 extends along the entire length of the slab 212, but in the fifteenth embodiment shown in Figure 35 of the drawings, the protrusion 216 extends beyond a lateral edge 222 of the slab 212, and defines a recess in the form of an elongate slot 224 in the laterally protruding part of the protrusion 216. The laterally protruding part of the protrusion 216 forms an attachment formation 226 for attaching the element 210 to another element in an end-to-end arrangement by attaching the protrusion 216 to the protrusion of the adjacent element, by means of a fastener extending through the slots 224 defined in each element 210, or by welding the protrusions 216 of the adjacent elements 210 together.

The slab 212 has the approximate shape of typical structural fence elements available in South Africa, which are configured to be receivable in lateral slots defined in spaced upstanding posts, by sliding the slabs into position along the slots. In order to be receivable in existing fences, the slab 212 typically has a length of 1 ,45 metres, which is about the same as the typical spacing between the slots into which the slab 212 is to be received.

The element 210 is made by positioning the metal protrusion 216 along one side of a mould (not shown), so that a part of the protrusion 216 extends into a cavity defined in the mould, the cavity having the required shape of the slab 212, and the protrusion 216 being positioned along the part of the mould corresponding to the upper edge of the slab 212. Concrete material is cast into the cavity and the mould is vibrated to allow air bubbles to escape from the concrete material, and the concrete is allowed to solidify by curing, while partly surrounding the protrusion 216, so that it becomes partly embedded in the concrete.

In use, the element 210 is slid into position along the lateral slots defined in two spaced upstanding posts, with the protrusion 216 protruding upwardly from the slab 212. The element 210 is typically installed on top of further elements similar in shape to the slab 212. The element 210 can also be used to replace elements in an existing fence.

The protrusions 216 of elements 210 installed in a fence, can be electrified, to serve as a further deterrent to intruders, by conducting electrical pulses through the protrusions 216, such as high voltage, low current pulses.

Referring to Figures 36 to 39 of the drawings, the structural element 210 includes a concrete casting in the form of a coping 228, in which a metal protrusion 216 is partly embedded. The protrusion 216 shown in Figure 38 has the same length as the coping 228, but extends beyond one end of the coping, and stops short of the opposite end of the coping.

In use, copings 228 are installed on top of fences, such as masonry fences by attaching an attachment face, or underside 232 to the fence with an adhesive, such as cement. As can be seen in Figure 39 of the drawings, the elements 210 are installed in an end-to-end arrangement with the end 230 of the protrusion 216 which extends beyond the end of the coping 228 being receivable in a slot defined in the adjacent element 210.

In other embodiments of the invention, the casting is made from a plastics material, so that the metal protrusion 216 is electrically insulated, and can readily be electrified.

The invention illustrated holds the advantages of allowing a perimeter fence 10 to be constructed or modified at relatively low cost, which can serve to inhibit trespassing. It holds the further advantage of allowing for the attachment and support of electrical conductors, such as the wires 26, which can be electrified to serve as a further deterrent to would-be trespassers.

The invention illustrated holds the further advantages of simple, quick, and inexpensive installation, structural integrity of the slab 212, and firm attachment of the protrusion 216 to the slab 212. It also holds the advantage of allowing existing fences to be retrofitted with the elements 210.

Claims

1. A method of constructing a fence (10), said method including: erecting two or more spaced, upstanding posts (12); attaching a bottom rail (14) to at least one pair of adjacent posts (12) to extend between the posts (12); attaching a top rail (16) to the pair of adjacent posts (12), in a spaced arrangement above the bottom rail (14), to extend between the posts (12); and attaching an infill (20,62) to at least two of the rails (14,16) and posts (12), to extend between the posts (12), characterised in that at least one of the rails (14,16) defines a plurality of upstanding spikes (18), extending generally upwardly.

2. A method as claimed in Claim 1 , characterised in that the infill is a wire mesh (62).

3. A method as claimed in Claim 2, characterised in that the infill (20,62) is attached to a rail (14,16) of the fence by: receiving a part of the infill in a vertex (58) of a resilient V-shaped clip (50); resiliently pressing the legs (56) of the clip (50) towards each other to narrow the V-shape of the clip; inserting the legs (56) of the clip (50) through an aperture (48) defined in the rail (14,16), to protrude through the aperture (48) on a side of the rail (14,16), opposite from the infill (20,62); and releasing the legs (56), allowing the V-shaped clip (50) to expand resiliently and abut the periphery of the aperture (48).

4. A method as claimed in Claim 3, characterised in that the V- shaped clip (50) is attached to the rail (14,16) by receiving protuberances (52) extending inwardly from a periphery of the aperture, in recesses (54) defined in the legs (56) of the clip (50).

5. A method as claimed in Claim 1 , characterised in that the infill includes spaced, upstanding elements (20), which are passed through apertures (48) in the top and bottom rails (16,14), each aperture (48) having a shape complemental to the cross-sectional profile of the upstanding elements (20), and wherein the upstanding elements 20 are welded to the top and bottom rails (16,14).

6. A method as claimed in any one of the preceding claims, characterised in that it includes attaching one or more midrails (70) to a pair of adjacent posts (12), to extend between the posts (12) in a spaced arrangement between the bottom rail (14) and the top rail (16).

7. A method as claimed in Claim 6, characterised in that at least one of the bottom rail (14) and top rail (16) defines a plurality of upstanding spikes (18), extending generally upwardly.

8. A method as claimed in Claim 6 or Claim 7, characterised in that the top, bottom and midrail (16,14,70) are attached to a post (12) at an angle, to allow the rails (16,14,70) to follow the profile of a landscape on which the fence is constructed, by pivotally attaching each rail (16,14,70) to the post (12), pivoting the rail (16,14,70) into a required position, and fastening the rail (16,14,70) to the post (12).

9. A method as claimed in any one of the preceding claims, characterised in that it includes attaching an electrical conductor (26) in an insulated fashion, to at least some of the spikes (18).

10. A method as claimed in any one of Claims 1 to 8, characterised by insulating at least one of the rails (16,14,70) from the fence (10), and electrifying the insulated rail (16,14,70).

11. A fence (10) which includes: at least two spaced, upstanding posts (12); a bottom rail (14) extending between at least two adjacent posts (12); a top rail (16) extending between the adjacent posts (12) in a spaced arrangement above the bottom rail (14); and an infill (20,62) extending between at least two of the rails (14,16) and adjacent posts (12), characterised in that the top rail (16) defines a plurality of upstanding spikes (18), extending generally upwardly.

12. A fence (10) as claimed in Claim 11 , characterise in that it includes at least one midrail (70) extending between the adjacent posts (12) in an arrangement spaced from the top rail (16) and bottom rail (14).

13. A fence (10) as claimed in Claim 12, characterised in that upstanding spikes (18) are defined on at least one of the bottom rail (14) and midrail (70), extending generally upwardly.

14. A fence (10) as claimed in any one of Claims 11 to 13, characterised in that the infill is a wire mesh (62), attached to the rails (14,16) by resilient V-shaped clips (50), with a part of the infill (62) received in a vertex (58) of each clip (50) and with the legs (56) of each V-shaped clip (50) abutting the periphery of an aperture (48) defined in the rail (14,16).

15. A fence (10) as claimed in Claim 14, characterised in that recesses (54) are defined in the legs (56) of at least some of the V-shaped clips (50), and at least some of the apertures (56) include protuberances (52) extending inwardly from a periphery of the aperture (48), and extending into the recesses (56) defined in the legs of the V-shaped clips (50).

16. A fence (10) as claimed in any one of Claims 11 to 15, characterised in that each post (12) defines a lateral recess (44) in which an end of one of the rails (14,16,70) is receivable.

17. A fence (10) as claimed in Claim 16, characterised in that each post (12) and each rail (14,16,70) include pivotal attachment means (22), for pivotally attaching the rail (14,16,70) to the post (12).

18. A fence (10) as claimed in any one of Claims 11 to 17, characterised in that it includes support formations (18,24,64) for receiving and supporting at least one electrical conductor (26), spaced above the fence (10).

19. A fence (10) as claimed in Claim 18, characterised in that the support formations include the spikes (18) extending generally upwardly from the fence (10).

20. A fence (10) as claimed in Claim 18 or Claim 19, characterised in that the support formations (18) define apertures for receiving insulating attachment formations (106) to which the conductor can be attached, while being electrically insulated from the fence (10).

21. A fence (10) as claimed in any one of Claims 11 to 20, characterised in that two laterally spaced posts (12), rails (14,16,70) extending between the posts (12), and an infill (20,62) extending between at least two of the rails (14,16,70) and posts (12), are attached together, and are moveable, to serve as a gate (66).

22. A structural fence element (210) which includes: a body (212) of cast material; and a protrusion (216), partly embedded in the body (212), characterised in that the protrusion (216) defines a sharp edge (218), protruding from one side of the body (212).

23. A structural fence element (210) as claimed in Claim 22, characterised in that the body (212) is a concrete casting.

24. A structural fence element (210) as claimed in Claim 22 or Claim 23, characterised in that the protrusion (216) is of a metal material.

25. A structural fence element (210) as claimed in any one of Claims 22 to 24, characterised in that the body is a slab (212), configured to be receivable in lateral slots, defined in spaced, upstanding posts, by sliding the slab into position along the slots, and in that the protrusion (216) is disposed on a side of the slab (212) forming an edge, so that it can protrude generally upwardly, when the slab (212) is received in the slots.

26. A structural fence element (210) as claimed in any one of Claims 22 to 24, characterised in that the body (212) is in the form of a coping (228) defining a fence engagement face (232) for attachment on top of a fence, with the protrusion (216) protruding generally in a direction, opposite from the fence engagement face (232).

27. A structural fence element (210) as claimed in any one of Claims 22 to 26, characterised in that the protrusion (216) extends along the length of the body (212), extends beyond one end of the body (212), and ends short of the opposite end of the body (212).

28. A structural fence element (210) as claimed in any one of Claims 22 to 26, characterised in that the protrusion extends along the length of the body (212) and extends beyond both ends of the body (212).

29. A structural fence element (210) as claimed in any one of Claims 22 to 28, characterised in that it includes attachment formations (226) for attaching it to another element (210) in an end-to-end arrangement.

30. A structural fence element (210) as claimed in Claim 29, characterised in that each attachment formation (226) is in the form of an aperture (224) defined close to one end (230) of the protrusion (216).

31. A method of making a structural fence element (210) as claimed in any one of Claims 22 to 30, said method including: providing a mould for making a casting (212), the mould defining a cavity having the required shape of the casting (212); positioning an article (216) along one side of the mould, so that a part of the article (216) extends into the cavity; casting a castable material into the cavity; and allowing the cast material to solidify, so that the article (216) becomes a protrusion, partly embedded in the casting (212), characterised in that the protrusion (216) defines a sharp edge (218) protruding from the casting (212).

32. A method as claimed in Claim 31 , characterised in that it includes an additional step of vibrating the mould before the cast material solidifies.

33. A method as claimed in Claim 31 or Claim 32, characterised by the step of installing the structural fence element (210) in a fence, with the sharp edge (218) of the protrusion (216) protruding generally upwardly from the structural fence element (210).

34. A method as claimed in Claim 33, characterised by sliding the structural fence element (210) into position along lateral slots defined in two spaced, upstanding posts.

35. A method as claimed in Claim 33, characterised by installing the structural fence element (210) by attaching it to the top of a fence in the form of a masonry fence.

36. A method as claimed in any one of the Claims 33 to 35, characterised in that the structural fence element (210) is electrified by conducting electric pulses through the protrusion (216).

37. A method as claimed in any of Claims 33 to 35, characterised in that the protrusion (216) includes supporting means (106) for supporting an electrical conductor (26).

38. A method as claimed in Claim 37, characterised in that the supporting means (106) is of an electrically insulating material, to insulate the conductor (26) from the protrusion (216).

39. A method as claimed in Claim 1 or Claim 31 , substantially as herein described and illustrated.

40. A fence (10) as claimed in Claim 11 , substantially as herein described and illustrated.

41. A fence element (210) as claimed in Claim 32, substantially as herein described and illustrated.

42. A new method of constructing a fence (10), a new method of making a fence element (210), a new fence (10), or a new fence element (210), substantially as herein described.