SAFETY BARRIER

The invention relates to a safety barrier (also known as a vehicle restraint system), particularly, but not exclusively, a safety barrier which is intended to be positioned at the end of another safety barrier. Such safety barriers are known as end terminals.

Safety barriers are used to prevent vehicles from crossing from one carriageway to the other, or from leaving the carriageway edge. In general, a safety barrier achieves this object by re-directing the vehicle along the line of the barrier. However, this is only possible where a vehicle strikes the barrier from one side of the barrier. An end terminal may be struck by a vehicle at its end, and so it would be beneficial if an end terminal were able to prevent a vehicle which has struck its end from re-entering the carriageway or leaving the carriageway edge.

It is an object of the invention seek to provide a safety barrier which is able to prevent a vehicle which has struck its end from re-entering the carriageway or leaving the carriageway edge, while retaining the capacity to re-direct a vehicle which has struck one of its sides.

According to a first aspect, the invention provides a safety barrier comprising a beam mounted on at least one support, the beam comprising at least one element which deforms when the loading is in line with the beam.

When the safety barrier of the invention is struck at its end, the element will deform and so absorb some of the energy of the impact. This means that the vehicle is less likely to be deflected back on to the carriageway or away from the carriageway.

The beam may comprise a plurality of said deformable elements. By providing a plurality of deformable elements, a greater amount of energy from the impact may be absorbed.

Said deformable elements may be connected to one another such that they deform in series when the loading is in line with the beam. This provides a more prolonged absorption of energy which will reduce the severity of the impact.

At least one of the deformable elements may comprise at least two spaced apart webs which extend between two deformable elements positioned on either side of said deformable element.

At least one web may extend between said spaced apart webs.

Said deformable element may comprise a hollow closed section of polygonal or rounded cross-section. For example, the deformable element may be of oval, square or rectangular cross-section. The deformable element may be equilateral or non-equilateral.

In a preferred embodiment, said deformable element is of hexagonal cross- section. The hexagon may be non-equilateral.

The barrier may comprise at least one side plate. A side plate will assist with end impacts, but its main function is to provide re-direction of a vehicle in the event of a side impact.

The barrier may comprise a plurality of overlapping side plates.

The side plate(s) may be non-planar. For example, the side plates may be bent so as to facilitate deformation of the side plates when the barrier is struck at its end.

Each side plate may include a plurality of spaced apart apertures. The apertures allow the side plates to be connected to the deformable elements and the overlap between two connected side plates to be varied.

Each aperture may comprise a slot. It will then be possible to connect overlapping side plates even if they have not been accurately positioned.

At least one deformable element may comprise an aperture for connecting said deformable element to one or more side plates.

The beam may be connected to at least one support by a connector mounted in a slot. In a first arrangement, at least part of the slot may be substantially parallel to the axis of the beam. The slot may be open at one end.

Using such a connection enables the support to disconnect from the beam when the loading is in line with the beam. Accordingly, the connection is "strong" in the lateral direction of the beam so that the support continues to support the beam in the event of a side impact, but "weak" in the axial direction of the beam so that the severity of the impact is reduced in the event of an end impact.

In this first arrangement, the beam may be connected to at least one support by an angle bracket, for example an L-shaped bracket.

Alternatively, the beam may be connected to at least one support by two angle brackets. By using two angle brackets it is possible to vary the spacing between the support and the deformable elements.

In a second arrangement, at least part of the slot may be substantially parallel to the support. The slot may be open at one end. The slot may be substantially T-shaped.

In this second arrangement, the beam may be connected to at least one support by a substantially planar bracket.

Similar arrangements are the subject of the applicant's co-pending application, also titled 'Safety Barrier', UK Patent Application No. 0601599.4.

The barrier may comprise a strike plate positioned at the end of the beam. The strike plate assists uniform transfer of energy to the beam.

The barrier may be an end terminal.

The barrier may be made of any suitable material such as galvanized steel.

According to a second aspect, the invention provides a safety barrier comprising a beam mounted on at least one support, the beam being connected to said at least one support by at least two angle brackets.

The invention will now be illustrated by way of example with reference to the following drawings of which:

Figure 1 shows a plan view of a safety barrier according to the invention;

Figure 2 shows a side view of the safety barrier of Figure 1;

Figure 3 shows a plan view of the connection between two deformable elements in the safety barrier of Figure 1;

Figure 4 shows a plan view of the connection between overlapping side plates and the deformable elements in the safety barrier of Figure 1;

Figure 5 shows a side view of the connection between overlapping side plates and the deformable elements shown in Figure 4;

Figure 6 shows a side view of a first embodiment of a connection between the supports and deformable elements which may be used in the safety barrier of Figure 1;

Figure 7 shows a plan view of the connection between the supports and deformable elements shown in Figure 6;

Figure 8a shows a plan view of the long flange of the first bracket of the connection shown in Figure 7;

Figure 8b shows a plan view of the short flange of the first bracket of the connection shown in Figure 7;

Figure 9a shows a plan view of the long flange of the second bracket of the connection shown in Figure 7;

Figure 9b shows a plan view of the short flange of the second bracket of the connection shown in Figure 7;

Figure 10 shows a plan view of the restrictor plate of the connection shown in Figure 7;

Figure 11 shows a second embodiment of the connection between the supports and the deformable elements;

Figure 12 shows a third embodiment of the connection between the supports and the deformable elements;

Figure 13 shows a fourth embodiment of the connection between the supports and the deformable elements;

Figure 14 shows a fifth embodiment of the connection between the supports and the deformable elements; and

Figure 15 shows a plan view of a second embodiment of the side plates.

The safety barrier shown in Figures 1 & 2 comprises a beam 1 mounted on a plurality of supports (posts) 2. The supports 2 are shown as being supported in concrete. In an alternative embodiment (not shown) a number of supports are welded to a ground plate which is then fixed in concrete. This facilitates installation.

The beam 1 comprises a plurality of deformable elements 3 connected to one another in series and a number of side plates 4 positioned on either side of the series of deformable elements 3.

Each deformable element 1 consists of a hollow section of hexagonal cross- section. The hexagon is non-equilateral (i.e. the sides are not of equal length). One pair 5 of parallel faces of the deformable element 3 is shorter than the other two pairs 6, 7 of parallel faces of the deformable element 3, so that the deformable element 3 is elongated in the direction of the axis of the beam 1.

The height and thickness of the deformable elements 3 may be selected to control the impact loading of the safety barrier. In the embodiment illustrated, the height of each deformable element 3 is slightly less than the height of the side plates 4.

As shown in Figure 3, the deformable elements 3 are connected together by a number of bolts 8 which pass through bolt holes 9 in the shorter faces 5 of the deformable elements.

Each side plate 4 consists of a rectangular strip. As shown in Figures 4 and 5, each side plate 4 includes a plurality of bolt holes 10 at one or both ends of the side plate 4 to enable the side plates 4 to be connected to each other and the deformable elements 3 by a plurality of bolts 11.

The bolt holes 10 are arranged in a pattern designed to allow the overlap between two connected side plates 4 to be varied. The pattern consists of a repeated series of units, each unit consisting of a pair of vertically spaced apart bolt holes 10 followed by a single bolt hole 10 which is horizontally spaced from the pair of bolt holes 10, so that the three bolt holes 10 form the apexes of a triangle.

Each bolt hole 10 comprises a slot so that it will still be possible to connect two overlapping side plates 4 together, even if they have not been accurately positioned. Alternatively, each bolt hole 10 may comprise a circular aperture. If the bolt holes 10 are circular, the side plates 4 should preferably be bolted together before they are connected to the deformable elements 3.

The thickness of the side plates 4 and the amount of overlap may be selected to control the impact loading of the safety barrier.

As may also be seen from Figures 4 and 5, each deformable element 3 comprises a pair of opposed apertures 12 to enable the side plates 4 to be connected to the deformable elements 3 by means of the bolts 11.

Each support 2 comprises a box section of rectangular cross section located in an open socket (not shown) which is concreted into the ground. Alternatively, each support 2 may be attached to a ground plate.

Each support 2 may be connected to the beam 1 in a number of different ways to enable the spacing between the supports 2 and the deformable elements 3 to be varied.

In the embodiment shown in Figures 6 to 10, the support 2 is attached to the beam 1 by means of two L-shaped brackets 13,14 and a restrictor plate 15.

Each bracket 13, 14 comprises two flanges 16, 17, 18, 19 of unequal length which are substantially perpendicular to one another.

In the first bracket 13, the longer flange 16 includes a slot 20 which is open at one end and closed at the other end. The slot 20 extends from a position close to the joint of the two flanges 16, 17 to the opposite edge of the flange 16. The other flange 17 of this bracket 13 includes two bolt holes 21.

In the second bracket 14, the longer flange 18 includes two bolt holes 22 and the shorter flange 19 includes one bolt hole 23.

The restrictor plate 15 comprises a square sheet 24 having a bolt hole 25 at its centre.

The first bracket 13 is positioned beneath the beam 1 with the shorter flange

17 abutting the support 2 and the longer flange 16 in line with the bottom of the side plate 4 and abutting the underside of two adjacent deformable elements 3. The restrictor plate 15 is then positioned beneath the longer flange 16, and the second bracket 14 is positioned on top of the first bracket 13 with the shorter flange 19 abutting the longer flange 16 of the first bracket 13 and the longer flange

18 abutting one of the deformable elements 3. The bolt holes 23, 25 in the shorter flange 19 of the second bracket 14 and the restrictor plate 15 are aligned and a bolt 26 is passed through those bolt holes 23, 25 and then through the slot 20 in the first bracket 13. Bolts 27 are also passed through the bolt holes 21, 22 in the shorter flange 17 of the first bracket 13 and the longer flange 18 of the second bracket 14, respectively to connect the first bracket 13 to the support 2 and the second bracket 14 to the deformable elements 3.

In the event of an impact, the slot 20 in the first bracket 13 will allow the supports 2 to disconnect from the beam 1.

The safety barrier shown in Figures 1 and 2 is being used as an end terminal. At one end, the safety barrier is connected to another safety barrier 28 by a closer plate 29 and at the other end there is a strike (or nose) plate 30. The other safety barrier 28 consists of a conventional safety barrier for use in the event of side impacts.

The strike plate 30 comprises a rectangular sheet which is attached to the end of the beam 1 such that it is substantially perpendicular to the beam 1, and projects both above and below the beam 1.

Figures 11 to 13 show three alternative embodiments of the connection between the supports 2 to the beam 1.

The arrangements of Figures 11 and 12 are similar to the arrangement of Figures 6 to 10, and make use of L-shaped brackets to vary the spacing between the support 2 and the deformable elements 3.

In the arrangement of Figure 13, the support 2 is attached to the beam 1 by means of a vertical square plate 31, which is bolted to a deformable element 3.

The vertical plate 31 includes two T-shaped slots 32 positioned side-by-side along the edge of the plate 31 which is opposite the edge which is bolted to the deformable element 3.

The vertical plate 31 is attached to the support 2 by two bolts 33, each of which passes through a slot 32.

In the event of an impact, the slots 32 in the vertical plate 31 will allow the supports 2 to disconnect from the beam 1.

The arrangement of Figure 14 is similar to that shown in Figure 13, although in this case the plate 34 consists of two sections 35, 36. The first section 35 is for fixing the plate 34 to a deformable element 3, and the second section 36 includes the two T-shaped slots 37.

Figure 15 shows a second embodiment of the side plates. In the preceding figures, the side plates 4 are shown as being planar. In the embodiment of Figure 15, the side plates 38 have been bent after assembly of the barrier. In particular, they have been bent at each part of the side plate 38 which is adjacent to the junction 39 between two deformable elements 40. The bends alternate in direction so that one bend projects towards the junction 39 and the next bend projects away from the junction 39. This is to facilitate deformation of the side plates when the barrier is struck at its end.

In the event of an end impact, the vehicle will strike the strike plate 30, and the energy of the impact will be transferred to the beam 1. The first deformable element 3 will collapse and the side plates 4 on either side of the deformable element will crumple.

If the energy of the impact is not yet dissipated, the vehicle will continue to move forward. As the vehicle moves forward, each support 2 it encounters will disconnect from the beam 1 so that they do not add to the severity of the impact.

In addition, the deformable elements 3 will continue to collapse one after the other, and the side plates 4 to crumple, until all the energy of the impact has been dissipated and the vehicle has been brought to a standstill.

If the vehicle has not been brought to a standstill by the time that all of the deformable elements 3 have collapsed, then the other safety barrier 28 will provide the necessary resistance to bring the vehicle to a halt.

In the event of a side impact, the deformable elements 3 and the side plates 4 will deform slightly, but the barrier will remain rigid so that the vehicle will be redirected along the line of the barrier.

One advantage of the barrier of the present invention is that its strength may be adjusted to suit different impact levels. This may be done by altering the thickness of certain elements which are used to construct the barrier, for example, the brackets and side plates. It may also be done by altering the quantity of certain elements which are used to construct the barrier, for example, the brackets and the posts. Thus, with the barrier of the present invention, it is possible to provide a modular system which can adapted to the requirements of the site where the safety barrier is to be assembled.

The above embodiments are described by way of example only. A number of possible variations will be apparent to the skilled person without departing from the scope of the claims.