HIGH SECURITY FENCE PANEL

Description

BACKGROUND OF THE INVENTION

This invention relates to a high security fence panel.

U.S. Pat. No. 11,454,043 describes a fence panel made from a mesh material to which spikes are attached. This type of spike is normally pressed from strip material. The manufacturing process may be such that a plurality of similar spikes are formed, substantially simultaneously, connected to one another by thin strip material, or a number of the spikes are fixed, using an automated process, to a base which acts as a carrier and which is also formed from a thin strip material.

FIG. 1 illustrates in perspective a typical assembly 10 of spikes 12 (prior art) which are made from strip material which has a thickness T. To meet cost and manufacturing considerations the thickness T of the strip material is typically of the order of 1 mm. In order to rigidify or stiffen each spike it is customary to form the spike with a central fold line C so that two triangular portions A, B, which are inclined to each other, extend outwardly from a base 14 which is integral with the spike. Alternatively each spike 12 is attached to a base 16 which is also made from the strip material and which also has a thickness T—see the end view in FIG. 2. However an elongate assembly 10 of the spikes is flexible and, depending on the manner of support for the assembly, is inclined to bend about a horizontal or longitudinal axis of the assembly.

The flexibility of the assembly of spikes is a negative feature but it is addressed in U.S. Pat. No. 11,454,043 when the spikes are attached to the mesh material which comprises a structure which is sufficiently robust or rigid to ensure that the spikes are correctly orientated on the mesh.

As described in U.S. Pat. No. 11,454,043 the sheet of mesh material in the fence panel is reinforced in two ways namely by means of parallel spaced apart lengths of flat bars which are welded to the mesh, and by the formation of a number of horizontally extending reinforcing formations each of which is in the form of a channel which is V or U-shaped.

The channels, apart from rigidifying the mesh sheet, provide a support mechanism whereby the spikes, once attached to the sides of the channels, can project upwardly or downwardly according to requirement. However the use of the reinforcing flat bar lengths comprises a separate manufacturing step and increases the cost of the panel.

The present invention is directed to addressing this aspect.

SUMMARY OF THE INVENTION

In contrast to the prior art technique in U.S. Pat. No. 11,454,043 wherein spikes formed from thin strip material, optionally carried on an elongate support of thin strip material (as per FIGS. 1 and 2) are directly attached to the sheet of mesh material the present invention provides that the spikes of strip material, individually or carried on a support, are attached to an elongate member which has greater strength and more rigidity than the strip material. The elongate member thereafter, is attached to the mesh.

The elongate member may be any appropriate material or shape of a suitable length and may be selected from a length of angle iron, of a square bar or a tube. Preferably the elongate member comprises a length of flat bar.

The approach adopted in the present invention means that the steps comprising the attachment of the spikes to the mesh material, and the reinforcement of the mesh sheet by attaching parallel spaced apart flat bars to the mesh, are combined. This holds a significant benefit.

During manufacture of the fence panel it is easier to attach flexible strips of spikes to fairly rigid lengths of flat bar (say) rather than attaching the strips of spikes to the irregular surface of a mesh sheet which is formed by a succession of spaced apart metal rods.

Secondly, the lengths of flat bar act as carriers for the spikes, whether of individual or strip form and, when secured to the mesh material, simultaneously secure the spikes to the mesh material and act as reinforcing components in the manner described in U.S. Pat. No. 11,454,043.

From an assessment of manufacturing techniques and an evaluation of materials which are available, without incurring additional cost, it has been established that the thickness of the flat bar should be at least three times the thickness of the strip material from which the spikes are formed. Similarly the inclusion of any elongate member, used instead of a flat bar, should be at least three times the thickness of the strip material, as explained hereinafter.

Although the use of flat bar is preferred the scope of the invention is not confined to this particular material and the elongate member which carries the spikes may be selected from a length of flat bar or angle iron, a square bar and a square or rectangular tube. An important feature is that the elongate member is attached to the mesh sheet, thereby to rigidify and strengthen the sheet, and simultaneously the elongate member acts as a carrier for the spikes or strips of spikes, thereby facilitating manufacture of the fence panel.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described by way of examples with reference to the accompanying drawings in which:

FIG. 3 illustrates how, in accordance with the invention, a strip of spikes of the kind shown in FIGS. 1 and 2 can be fixed to a reinforcing elongate member,

FIG. 4 is similar to FIG. 3 illustrating a variation of the invention,

FIGS. 5 to 8 show in cross section different elongate members with spikes attached thereto in accordance with the invention,

FIG. 9 is a view in elevation of a fence which includes a fence panel according to the invention,

FIG. 9A shows the fence panel from one side,

FIG. 9B shows a part of a sheet of mesh material,

FIG. 10 shows a different form of a fence panel according to the invention,

FIG. 10A shows the fence panel of FIG. 10 from one side,

FIGS. 11 and 12 show different spike configurations on mesh panels,

FIG. 13 shows a planar mesh sheet which is reinforced with flat bars which carry spikes, and

FIG. 14 depicts a dimensional aspect of the spikes.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 3 of the accompanying drawings illustrates in perspective how the assembly 10 of spikes 12 shown in FIG. 1 is used in accordance with the principles of the invention.

The assembly 10, under factory conditions, is attached using rivets or bolts or other fasteners 22, at regular intervals, to a length 24 of flat bar.

FIG. 4 illustrates a different version of the invention wherein an assembly 26 of spikes 12 carried on a base 28 of thin strip material, which has the same thickness as the material from which the spikes are made, is attached to an elongate carrier 30 comprising a length of flat bar, at regular intervals, by means of rivets, bolts, spot welding 32, or the like.

FIGS. 3 and 4 illustrate the use of flat bar lengths to support the spikes.

FIG. 5 illustrates the arrangement in FIG. 3, or in FIG. 4 from one end. The spikes 12 are shown extending from a base 28, as per FIG. 4, although, as stated, in one form of construction the spikes 12 are integrally formed with a suitable base 16 in strip form as shown generally in FIG. 1. The base 28 (or the bases 16 of the individual spikes) has a thickness T and the length (24 or 30) of flat bar has a thickness D.

D is at least three times the dimension T and consequently the assembly shown in FIG. 5 has substantial stiffness. The assembly of spikes 12 which is attached to the flat bar 24/30 is rigidified and supported by the flat bar-this makes the task of attaching the spikes to a mesh sheet, as is explained hereafter, considerably easier.

As indicated hereinbefore the principles of the invention are not confined to the use of a length of flat bar to carry the spikes. FIG. 6 illustrates spikes 12 attached to a length 38 of square bar with a thickness D-such that D≥3T.

In FIG. 7 a length 40 of angle iron with a flange with a thickness D is used to support the spikes—the dimensions are such that D≥3T.

FIG. 8 illustrates another possible variation wherein a length 42 of a rectangular tube is used as an elongate support to which the spikes 12 are attached using techniques similar to those shown in FIGS. 3 and 4, for example.

The tube 42 has a dimension D between outer opposed faces and D≥3T. Due to the bracing effect of the side walls of the tube the tube has considerable rigidity and is an adequate carrier for the spikes.

The various configurations of spikes attached to elongate supporting members as referred to hereinbefore, can be used in different ways in the fabrication of a high security fence panel. The elongate member, typically a flat bar (this is illustrative and non-limiting) is used to rigidify a mesh panel and at the same time to secure deterrent metallic spikes to the mesh material. This process is easier to accomplish than directly attaching the spikes on a thin material base to the mesh material and, moreover, the elongate member, e.g. the flat bar, is chosen so that it has sufficient strength to rigidify the mesh material as described in the aforementioned US specification. This is in addition to the use of channels in the mesh material which are formed at appropriate locations to rigidify the mesh material.

FIG. 9 of the accompanying drawings illustrates in elevation a fence panel 110 according to the invention which forms a part of a fence 112 erected on the ground 114 along a fence line, not shown.

The panel 110 is positioned between and attached to two spaced apart vertically extending posts 116 and 118 planted in the ground 114. Extending upwardly from the posts are supports 120 to which are attached wires 122 which form part of an electrified fence.

The panel 110 comprises a sheet 124 of mesh material a portion of which is shown in FIG. 9B. The mesh material has mesh apertures 126 of rectangular form. A long dimension 128 of each mesh aperture extends horizontally while a short dimension 130 of each mesh aperture extends vertically. This is of significance for the arrangement offers greater visibility, i.e. a see-through capability, than if the long dimension extended vertically and the short dimension extended horizontally.

The mesh is formed from transverse arrays of wires or rods of a suitable dimension which are attached e.g. welded to one another at points of contact. Optionally flat bars 132 are attached to the mesh 124.

The panel 110 has an upper edge 144, a lower edge 146 and opposed vertically extending edges 148 and 150. The vertical edges 148 and 150 are shaped to form flanges which facilitate direct attachment of the panel to the posts 116 and 118 respectively. This is done using anti-vandal bolts or other fasteners which are readily installed but which can only be removed with difficulty. This feature is neat and attractive and allows for erection of the panels at a low cost.

In one embodiment at least one row of spikes but preferably three rows A, B and C of spikes, in the form of elongate strips, are fixed to the mesh panel adjacent the upper edge 144. In a second embodiment, to extend the security value of the fence at least one row of spikes, but preferably at least three rows of spikes X, Y and Z are fixed to the mesh panel at its lower edge.

It is possible to cover the entire mesh sheet 124 with spikes K as shown in FIG. 10, i.e. rows of spikes which traverse the sheet between the vertical side edges of the mesh. This substantially increases the deterrent value of the fence panel but carries with it disadvantages of an increased cost, and weight. As a compromise a central portion of the panel can have spikes attached to it - the density of the spikes in that central region of the mesh panel may be the same as, or lower than elsewhere, e.g. A, B, C per unit area and X, Y, Z per unit area.

FIG. 9A shows the fence panel of FIG. 9, from one side while FIG. 11 is a similar illustration but on an enlarged scale.

FIG. 10A illustrates from one side a portion of the fence panel of FIG. 10. The panel is formed with channels 150 which extend horizontally i.e. from one vertical edge to the other vertical edge. These channels stiffen the mesh and increase the resistance of the mesh to bending. Spikes are attached to each of these channels in a high security embodiment of the fence. This is also the construction of the panel in FIG. 9.

The channels 150 which in cross section are V or U-shaped perform two functions. Firstly the channels reinforce and rigidify the mesh sheet 124. Secondly each channel presents an upwardly sloping side 150A and a downwardly sloping side 150B which extend from a point 150C at which the sides intersect. This feature allows the spikes, marked 152 in FIG. 11 to be positioned so that they all face generally in the same direction and extend upwardly. In a more complex configuration, shown from the side in FIG. 12, the spikes 152 are attached to the sides 150A and 150B of each channel and form an array of upwardly extending spikes 152A and a downwardly extending array of spikes 152B.

In a different configuration the rows of spikes extend vertically, adjacent the vertical edges of the mesh sheet. It is also possible for rows of spikes, of different lengths, to cover the entire mesh sheet i.e. with some rows vertical, and other rows horizontal.

An important feature of the invention is shown in FIGS. 9A and 10A. The lower edge 146 is configured to accommodate a set of spikes 156 some of which may project into the ground 114 to a slight extent. The lowermost spikes make it extremely difficult for an intruder to breach the fence by passing through a gap between the lower edge of the panel and the ground. The spikes 156 can be increased in number and in length to enhance their deterrent effect.

Additionally, for security purposes, mesh material is buried in the ground or a concrete foundation 160 is cast in the ground below the fence (FIG. 9A and FIG. 10A) so that it is difficult to dig under the fence to breach the fence. A different approach calls for embedding in the ground, possibly in concrete, rows of spikes, attached to a lower edge of the mesh, to inhibit the digging of a tunnel below the mesh panel. The capability of cutting through the fence panel i.e. severing the spikes A, B, C and X, Y, Z and the adjacent mesh is also demanding. It is difficult and in fact dangerous to attempt to scale the fence because the spikes are sharp and can penetrate a person's skin. Additionally the fence is topped with electric wires and this acts as a significant deterrent.

Another factor which helps with security is the density of the spikes i.e. the number of spikes per unit area. FIG. 14 shows that the tips of adjacent spikes 12 are spaced apart by a distance 162 which is less than 100 mm and preferably which is of the order of 50 mm or less. This distance is not arbitrary, but has been found through tests and evaluation to provide a good compromise between cost and deterrent value. The number of spikes per unit area does increase cost but there are significant security benefits associated therewith. Each spike has a V-shape and is stiffened with a central fold line as described. The spike extends from a base which in use is fixed to a mesh sheet via a length of flat bar.

FIG. 13 illustrates in perspective a preferred embodiment of the invention wherein an array of spikes 12 which project from lengths 24/30 of flat bar as per FIG. 3 or 4, are attached to a planar mesh sheet 164.

The provision of the spikes on an elongate member which comprises a solid support such as the flat bar or square bar of FIGS. 5 and 6, or on a tubular support as shown in FIG. 8, is important. The elongate member is selected so that it acts as a strong base from which the deterrent spikes project. Additionally the elongate member is chosen to have substantial strength, e.g. in the form of a flat bar or a tube so that, once attached to the mesh material the elongate member significantly reinforces and rigidifies the mesh.

The spikes which are carried by the elongate member comprise a primary deterrent. An intruder wishing to breach the fence panel of the invention must overcome the danger which is presented by the array of spikes on the mesh. It is necessary to sever the elongate member from which the spikes project and, additionally, to penetrate the mesh material. If the panel of the invention has a high density of spikes the aforementioned exercise is difficult and time consuming.

It is not easy for an intruder to climb over the fence panel of the invention particularly if the panel is topped with electric fencing. An attempt to burrow through the ground below the panel must overcome the obstacle presented by the concrete foundation at the base of the panel as shown for example in FIG. 9A.

A barrier made from panels of the kind described is difficult to breach but still offers a good see-through capability.