Fence panel

Abstract

A fence panel is provided that includes a first set of horizontal parallel spaced apart wires sandwiched between a second and third set of vertical wires spot-welded to either side of the first set of wires. At least some of the individual wires of the second set are opposite wires of the third set to form adjacent pairs of vertical wires. The wires are made from high tensile steel with a diameter of between 2 and 8 mm and the elements of the second and third sets are spaced apart 3 to 10 times as far as the elements of the first set of wires. The fence panel has a length of about 3 m, height of about 3m and weight of about 10.5 kg/M2.

Description

FIELD OF THE INVENTION

This invention relates to a fence panel and, more particularly, to a fence panel of a grid-like construction.

BACKGROUND TO THE INVENTION

Fences used in and around prisons, highways, airports and the like must provide good visibility therethrough, even when viewed at an acute angle, and must be robust enough so as not to be easily breached.

Fences of a grid-like construction with vertical wires spaced relatively far apart in relation to horizontal wires are known. Such a configuration generally allows good visibility through the fence. However, a fence constructed of a single set of vertical and horizontal wires may not be robust enough.

Grid fences of the type described above, but where pairs of adjacent horizontal wires are fixed on opposite sides of the uprights, are also known. These fences, however, have been known to be broken by inserting a lever between pairs of horizontal wires and prising them apart. They can also be breached by severing a number of adjacent uprights at the same horizontal level and biasing the broken ends apart to create a gap. Finally, these fences have also been known to topple when strong horizontal forces, such as powerful winds, occur, and generally require a lot of material for their construction, making them relatively expensive and heavy.

In this specification any reference to the “horizontal” or “vertical” orientation of an element, wire or fence panel will be understood to refer to the fence panel in its operative upright position.

OBJECT OF THE INVENTION

It is an object of this invention to provide a fence panel that, at least partially, alleviates some of the abovementioned problems.

SUMMARY OF THE INVENTION

In accordance with this invention there is provided a fence panel comprising a first set of horizontal parallel elongate elements spaced apart to form a panel having first and second sided; a second set of vertical parallel elongate elements fixed to the first side of the panel; and a third set of vertical parallel elongate elements fixed to the second side of the panel, wherein at least some of the elements of the third set are opposite elements of the second set to form adjacent pairs of vertical elongate elements.

Further features of the invention provide for the second set of elements and the third set of elements to be spot-welded to the first set of elements; for the elongate elements to be high tensile steel wire; and for the steel wire to have a diameter of between 2 mm and 8 mm.

Still further features of the invention provide for the second set of elements to be spaced apart 3 to 10 times as far as the first set of elements; and for the first set of elements to be spaced about 13 mm apart and the second set of elements to be spaced about 76 mm apart.

The fence panel may have a length of about 3 m, a height of about 3 m; and a weight of about 10.5 kg/m².

According to one aspect of the invention the third set of elongate elements may extend partway along the height of the panel and the first set extend along the full height of the panel to form a fence panel having single vertical elongate elements at its operatively upper section and pairs of vertical elongate elements at its operatively lower section.

The invention extends to a fence including a plurality of fence panels according to the invention supported by uprights.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example only, with reference to the drawings in which:

FIG. 1 is a perspective view and an end view a prior art fence panel;

FIG. 2 is a perspective view of a second prior art fence panel;

FIG. 3 is a perspective view and an end view of a third prior art fence panel;

FIG. 4 is a perspective view of the fence panel of FIG. 2 with two wires cut to form a breach; and

FIG. 5 is a perspective view of a fence panel in accordance with the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

It will be understood that the fence panels described may be supported by various structures, including upright steel poles or concrete pillars. Such structures are well-known and are not described herein.

FIG. 1 shows a prior art fence panel (1). The fence panel (1) has a first set of parallel spaced apart wires (2) that form a panel with a first side (4) and a second side (6). A second set of parallel spaced apart wires (8) extend on the first side (4) normally to the first set of wires (2). The second set of wires (8) are spaced apart substantially further than the first set of wires (2), so that when the fence panel (1) is erected in the orientation shown with the first set of wires (2) extending horizontally, an object (10) is visible through the fence panel (1), even when a viewer (12) is at an acute angle thereto.

FIG. 2 shows a second prior art fence panel (20), of a similar construction to the fence panel (1) in FIG. 1, but which has been reinforced with additional wies. The fence panel (20) has a first side (24) and a second side (26). A first set of parallel spaced apart wires (22) extend on the second side (26), a second set of spaced apart parallel wires (28) extend normally to the first set of wires (22) and a third set of wires (22) and a third set of parallel spaced apart wires (30) extend in parallel with the first set (22) on the first side (24) so that the second set of wires (28) and sandwiched between the first set (22) and the third set (30). Individual wires of the first set (22) and the third set (30) are aligned so that they form adjacent pairs of wires (32) on opposite sides (24, 26) of the panel. The weight of the fence panel (20) is typically in the order of 17.3 Kg/m².

The fence panel (20) shown in FIG. 2 is more robust than the fence panel (1) of FIG. 1. There are more wires to cut and it is also more difficult to cut the pairs of wires (32) with a wire cutter.

However the fence panel (20) of FIG. 2 has a particular disadvantage. As shown in FIG. 2, the fence panel (20) can be broken by inserting a lever, such as a screwdriver or, in this case, a crowbar (34) between pairs of wires (32) and prising them apart. The fence panel (20) also uses substantially more wire than the panel (1) in FIG. 1, making it heavier and more expensive to manufacture.

FIG. 3 shows a third prior art fence panel (40) of similar construction to the fence panel (20) of FIG. 2, but where one side (44) of the panel (40) has wires (42) that are spaced apart more widely than the wires (48) on the opposite side (46) of the panel (40). This fence panel (40) uses less material than the fence panel (20) in FIG. 2, but is proportionately weaker and can also be broken using a screwdriver or crowbar (34) in the manner illustrated in FIG. 2. The weight of the fence panel (40) is typically in the order of 10.9 Kg/M².

FIG. 4 shows the fence panel (20) of FIG. 2 which has been breached by severing a number of adjacent wires of the second set of wires (28) at a level in line with an element of the first set of wires (22). The broken sections have been biased apart to create a gap (29). The fence panel (1) of FIGS. 1 and 3 can also be similarly breached. Such a breach can be created at a lower end of the fence panel where it is difficult to detect by security personnel. Individual elements of the second set of wires (28) can be cut over a period of time to make the breach even harder to detect.

FIG. 5 shows a fence panel (50) in accordance with the invention. The fence panel (50) has a first set of horizontal spaced apart parallel wires (52) that form a panel with a first side (54) and a second side (56). A second set of vertical parallel spaced apart wires (58) are spot-welded to the second side (54) and a third set of vertical parallel spaced apart wires (60) are spot-welded to the second side (56) of the panel. Individual wires of the second set of wires (58) and the third set of wires (60) are aligned opposite each other to form pairs of adjacent vertical wires (62). The spacing between the individual wires of the second and third set of wires (58, 60) is typically about 76 mm, while the spacing between individual wires of the first set of wires (52) is about 13 mm. The wires are high-tensile steel wire having a diameter of about 4 mm and are spot-welded together.

The typical weight of a fence panel shown in FIG. 5 has been found to be about 10.5 kg/M². By contrast, the weight of the panel shown in FIG. 3 was found to be about 10.9 kg/M² while the weight of the panel shown in FIGS. 2 and 4 was found to be about 17.3 kg/M². The pairs of wires (58) in the panel (50) of FIG. 5 can also not be easily levered apart, because the gap (64) in which a lever would be wedged is typically too small to admit a crowbar, screwdriver or other effective levering device. The panel (50) of FIG. 5 is also more difficult to breach in the manner illustrated in FIG. 4, because the first and second wires (60, 62) would both have to be severed, and because the wires (60, 62) provide additional rigidity against being bent in the manner illustrated in FIG. 4. Finally, when erected in the configuration shown in FIG. 5 where the first and second wires (60, 62) extend vertically, these wires provide additional support against horizontal forces, such as strong winds, that tend to topple the fence panel (50). The fence panel (50) shown in FIG. 5 can therefore be erected within a support structure (not shown) which is cheaper that the support structure required for the prior art fence panels referred to above.

Intersecting wires of the fence panel can be welded together by means of a mechanical hand operated process or by means of a semi of fully automated process.

The invention therefore provides a fence panel or relatively lightweight construction, having elongate elements that cannot easily be broken by being prised apart with a lever, which is of a relatively robust construction and does not easily topple and which provides good visibility through the fence panel when viewed at an acute angle.

It will be appreciated that other embodiments of a fence panel may be devised that fall within the scope of the invention, especially as regards the exact configuration thereof. For example, it is not necessary for the second set of elements to all be in pairs. A configuration with every third element in pairs with two single wires between every pair could be used.

The fence panel can also have pairs of adjacent vertical elongate elements at its operatively lower section and single vertical elongate elements of the second set at the operatively upper section of the fence panel. It has been found that breaches in security fences normally occur at eye level or lower. This section can therefore be constructed as described in the invention, while the higher part of the fence panel can be constructed with only two sets of wires, similar to the fence panel shown in FIG. 1.

The fence panel (50) will typically have a width of about 3 metres and a height of 3 metres or higher, up to about 6 metres.

Claims

1. A fence panel comprising:

a first set of horizontal parallel elongate elements spaced apart to form a panel having first and second sides;

a second set of vertical parallel elongate elements fixed to the first side of the panel; and

a third set of vertical parallel elongate elements fixed to the second side of the panel;

wherein at least some of the elements of the third set are opposite elements of the second set to form adjacent pairs of vertical elongate elements.

2. A fence panel as claimed in claim 1 in which the second set of elements and the third set of elements are spot-welded to the first set of elements.

3. A fence panel as claimed in claim 1 in which the elongate elements are high tensile steel wire.

4. A fence panel as claimed in claim 3 in which the steel wire has a diameter of between 2 mm and 8 mm.

5. A fence panel as claimed in claim 1 in which the second set of elements are spaced apart 3 to 10 times as far as the first set of elements.

6. A fence panel as claimed in claim 5 in which the first set of elements are spaced about 13 mm apart and the second set of elements are spaced about 76 mm apart.

7. A fence panel as claimed in claim 1 having a length of about 3 m and a height of about 3 m.

8. A fence panel as claimed in claim 1 having a weight of about 10.5 kg/m2.

9. A fence panel as claimed in claim 1 in which the third set of elongate elements extends partway along the height of the panel and the first set extends along the full height of the panel to form a fence panel having single vertical elongate elements at its operatively upper section and pairs of vertical elongate elements at its operatively lower section.

10. A fence including a plurality of fence panels as claimed in claim 1 supported by uprights.

11. (canceled)