In equestrian eventing and similar activities a horse and rider have to negotiate barriers which may typically be comprised of logs of wood or barriers of corresponding shape made of synthetic materials such as plastics and glass fibre composite. In each case, the barrier has to be sufficiently strong to withstand the shock of impact by a horse without breaking, even if the barrier is mounted in such a way that a collision into it by a horse and rider would not normally dislodge or break it. This presents a problem as a potential safety hazard for, in particular, the rider. Several fatalities have occurred by horses not negotiating such barriers successfully, when the rider is catapulted forwards and the horse then rolls over the barrier onto the rider. Although it would be possible to alleviate this hazard by the use of lightweight, bendable or breakable barriers, this is. deemed to considerably lessen the natural thrill of eventing.

This problem is exacerbated by the lack of uniformity of many of the materials used for such barriers and support posts etc, For example, if such are made from wood by cutting down trees and branches etc the barrier itself will have a natural taper and, depending upon the wood from which it is made and e. g. support posts used therewith, the stiffness and hardness of the wood provide inherent variables. Another problem is that these barriers can be of widely varying diameters, typically between 150mm and 300mm, so that it is difficult to adopt any common standard in the event that safety features are to be adopted which would prevent or inhibit the injury of riders in such circumstances.

The present invention is derived from the realisation that it would be advantageous to have a barrier safety system which retains the thrill of eventing and other similar activities but which provides for the barrier to be removed as an obstacle upon the application of a vertically downward load within or above a given range, even though a variety of different types and sizes of barrier rails are used.

According to the invention there is provided a barrier safety system for supporting a generally horizontally disposed barrier rail of generally circular- section between a pair of generally vertically disposed upright members, such as posts, the system comprising a pair of sockets, one for each upright member and a pair of barrier rail support pins, one for each socket, each support pin being insertable at one end into a respective socket and including near to that end a weakened portion, at which point the support pin will break upon the application of a vertically downward load onto the barrier rail within or above a desired range of loads.

Conveniently, the weakened portion of the support pin for each socket comprises a waist region which is designed to break if a vertically downward load is applied to the pin within or above a given range, such as between 6kN and 7.5kN and above.

In a preferred embodiment of the invention one or more stop members are provided between the weakened portion and the socket to vary the distance the support pin may be inserted into the socket so as to accommodate different sizes of barrier rails : This ensures that similar bending moments and hence leverages apply to the weakened portion even though-barrier rails of different diameters are used, such that they all break the pin when the same or a similar load has been applied to the top of the barrier rail by e. g. a horse failing onto it.

This has the advantage in that by being able to adjust the distance by which each support pin extends out of its respective socket it is possible to easily and quickly compensate for different diameters of barrier rail so that, effectively, the distance between the weakened portion of the support pin and the point of contact with the bottom of the barrier rail and the support pin can compensate for what otherwise would be an increase in the leverage available to break the support pin by a barrier rail of relatively large diameter as compared to one of a smaller diameter, and vice versa. In this way breakage of the pin is more likely to occur within the desired range irrespective of whether a barrier rail of relatively large diameter, say 250mm, is being used instead of a barrier rail of, say, 170mm diameter.

Conveniently, the stop members comprise stop pins receivable in respective bores in the support pin for each socket, the bores being substantially at right angles to the major axis thereof.

Each support pin is preferably made of a substantially non-ductile material, such that energy is not absorbed by plastic bending of the pin, but that the pin snaps when the desired load limit is reached. It has been found that a suitable material is an aluminium alloy ref : 6061T6 made in accordance with BS 8118 Part 1 has the necessary properties, this alloy being composed of aluminium alloyed with 0.69% silicon, 0. 41% iron, 0.22% copper, 0.05% manganese, 0.90% magnesium, 0. 15% chromium, 0. 011% titanium and 0. 01% zinc.

Conveniently, the socket for each pin is in the form of a tube for receiving a respective support pin, and a flange may be provided at one end thereof, the flange being in the form of a large plate adapted to be secured to an upright member, which may be a wooden post. The flange plate may conveniently include apertures for securing it to an upright member, e. g. by bolts etc.

In a preferred embodiment of the invention each pin is provided with a marker to assist in setting the pin within a respective socket to the correct distance relative to the diameter of the barrier rail, the marker being aligned vertically below the centre of the barrier rail. In addition, the weakened portion of the pin is provided by means of a sharp, radially disposed, "vee"-shaped notch, thereby providing a correspondingly sharp fracture point.

The invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows in part section a barrier safety system according to a first embodiment of the invention, and Figure 2 shows in part section a barrier safety system according to a second embodiment of the invention.

Referring firstly to Figure 1, a barrier safety system for supporting one end of a barrier rail 1 (shown partially in broken outline) is supported on an upright member in the form of a wooden post 2 (only part of which is shown), the other end of the barrier 1 being supported in the same manner on another upright post.

The barrier safety system shown generally at 3 includes on this end of the barrier 1 a socket 4 having an integral flange 5 including apertures (not shown) through which respective bolts 6 and 7 can secure the socket 4 to the post 2, the relatively large size of the flange 5 helping to stabilise the positioning of the socket 4 within the post 2 and therefore helping to prevent or inhibit any movement thereof.

The barrier safety system 3 also includes an elongated generally circular support pin 8 made of a substantially non-ductile material such as aluminium alloy (BS ref. 6061 T6) and includes a weakened portion 9 in the form of a waist which, as is explained in further detail later, is designed to fracture upon the imposition of a vertically downward load onto the pin 8 at, in this example, the point of contact 'A'of the barrier rail 1 with the pin 8.

The pin 8 is secured in its selected position by means of a stop pin 10 which is slidingly received in staple 11 fixed to the flange 5, and through a correspondingly shaped bore 12 through the support pin 8, there being two other bores 13,14 through which the stop pin 10 may also be inserted if preferred.

In the position illustrated, it will be appreciated that a vertically downward load acting at the point of contact"A"from the barrier rail 1 to the support pin 8 will induce a turning moment or leverage effect around the weakened portion 9. In tests using a 250mm diameter barrier rail 1 where the diameter of the support pin 8 was 30mm, the weakened portion 9 having a 26mm diameter and being positioned 45mm from the major plane of the flange 5, failure of the support pin 8 at the weakened portion 9 occurred with a vertically downward load of 6. 09kN.

Using a barrier rail 1 having a diameter of 200mm and inserting the support pin 8 into the socket 4 up to the point when the stop pin 10 can be inserted into the bore 13 and into the staple 11, this being approximately 30mm from the major plane of the flanges, where the point of contact of the barrier rail 1 with the support pin 8 would then occur at point'B' (relative to the flange 5), it was found that the support pin 8 failed at the weakened portion 9 under a failure load of 6. 90kN. Similarly, using a barrier rail 1 of only 180mm diameter and sliding the support pin 8 further into the socket 4 up to the point where the stop pin 10 can be inserted into the bore 14 and the staple 11, this being approximately 15mm from the weakened portion 9, it was found that a load applied at position C representing the point of contact of the barrier rail 1 with the support pin 8, a vertically downward load of 6.47kN produced failure of the support pin 8 at the weakened portion 9.

Hence, in this embodiment, it will be apparent that by compensating for what would otherwise be significantly different turning moments about the weakened portion 9 through the use of barrier rails of different diameters, it is possible to provide a barrier safety system for use with a range of barriers of different diameters using the same support pins 8, suitably adjusted as to depth of entry into the respective sockets 4, in which failure of support pin 8 can be expected above a given threshold.

Through the use of a relatively large flange 5, which essentially stabilises the position of the socket 4, and the use of a substantially non-ductile material for the support pin 8, substantially all of the energy from the vertically downward load imposed by, typically, a horse landing on top of the barrier rail 1 can be focused on the weakened portion 9 of the support pin 8, irrespective of the diameter and weight of the barrier rail 1 such that even if it is made out of relatively lightweight materials, such as tubular aluminium, it will still provide the same end result i. e. a failure of one or both the support pins 8.

Referring now to Figure 2, this shows a second, preferred, embodiment of barrier safety system shown generally at 3a in which the socket 4a is in the form of a thickened tube, part of which is shown in section for clarity. In tests it has been found that very satisfactory results can be obtained by the use of such a relatively thick walled socket which dispenses with the need for the flange 5 of Figure 1 and also makes it easier to fit it within the post 2, by simply driving it into a suitably sized bore.

The-pin 8a in this embodiment of the invention also includes a weakened portion in the form of a radially disposed"vee"-shaped notch 9a which provides a more sharply defined fracture point than the waist 9 of Figure 1. In addition, in order to assist in locating the correct depth within the socket 4a the pin 8a must be inserted, a marker in the form of a radially disposed groove 15 is provided. This allows a person setting up the safety barrier system to insert the pin 8a into the socket 4a, offer up the barrier rail 1 to the post 2 and then to adjust the depth of insertion of the pin 8a so that the marker 15 lies immediately beneath the centre of the rail 1, at which point a stop member in the form of a pin (not shown) is inserted into one of the bores 12,13 or 14, the choice of which being dictated by the diameter of the barrier rail 1 which, in the case of that shown in Figure 2, is bore 14. However, as will be apparent, in the event of the barrier rail 1 being of a larger diameter, the pin 8a and hence marker 15 would need to be moved to the right, thereby exposing, progressively, bore 13 and, for the largest diameter barrier rail 1 bore 12. In this embodiment, a stop member in the form of a stop pin (not shown) is inserted into a bore 16 in one side of the socket 4a and, following alignment with a respective bore 12,13 or 14 in the barrier rail support pin 8a, is then inserted into a second bore 17 on the other side of the socket 4a to complete the assembly, thereby preventing the support pin 8a from accidentally moving in either axial direction and thus ensuring that the fracture point provided by the notch 9a remains a constant distance from the point of contact with the barrier rail 1.

Although two embodiments of the invention have been shown, in both of which the bores 12, 13 and 14 into which correspondingly shaped stop members may be inserted to adjust the effective length by which the support pins project from their respective sockets, nevertheless it will be apparent that other means of achieving this objective may be adopted without departing from the spirit or scope of the invention. Similarly, although pins and respective sockets are preferably circular in cross-section it will be understood that other shapes may be adopted as may also other forms of weakened portions for the pins, again without departing from the spirit or scope of the invention.