WO2000047824A1

WO2000047824A1 - Safety barrier

Info

Publication number: WO2000047824A1
Application number: PCT/AU2000/000082
Authority: WO
Inventors: Andrew William Coffey
Original assignee: Airfence Safety Systems (Australia) Pty Ltd.
Priority date: 1999-02-11
Filing date: 2000-02-10
Publication date: 2000-08-17
Also published as: AUPP860699A0

Abstract

A safety barrier (10) for absorbing the impact of a moving body, including a frame (12) formed of a resiliently collapsible material and a covering (11) formed of a flexible material extending about the frame (12) and being supported thereby. The covering (11) defining an internal chamber (23) which communicates with atmosphere through an exhaust opening (24) formed in the covering (11), and the pressure within the chamber (32) being ambient in absence of an impacting body. The barrier (10) at least partly collapsing under the influence of an impacting body, in a manner that the internal chamber (32) reduces in volume and the pressure within the chamber increases, thus resisting further reduction in the chamber volume. The exhaust opening (24) permitting controlled exhaust of air from within the chamber (23) under an impact.

Description

SAFETY BARRIER

The present invention relates to a safety barrier and particularly, although not exclusively, relates to a safety barrier for absorbing the impact of moving bodies or vehicles, such as cars or motorbikes and the drivers/riders of those vehicles, during racing thereof. It will therefore be convenient to describe the invention in relation to that application, although it is to be appreciated that the invention could have wider application.

Safety barriers at racing circuits are used to decelerate and stop the racing vehicle and/or driver/rider when the vehicle leaves the race track unexpectedly. Different barriers can be used for different sections of the race track, depending on the likelihood of a vehicle leaving the track and the likely speed and direction of the vehicle. For example, a vehicle is more likely to leave the track on a bend section than a straight section and in a bend section, the vehicle is more likely to hit a safety barrier at a higher impact angle. Straight sections of a track, therefore do not necessarily require a safety barrier, while it is mandatory, at least for most world class races, for dangerous track bends to be protected by safety barriers.

Safety barriers can take a variety of forms and in a rudimentary form, they can consist simply of hay bales or stacked car tyres.

An alternative style of barrier consists of a wide space of graded gravel or sand, bounded by a barrier wall. The gravel or sand decelerates a vehicle that leaves the track and the barrier wall stops the vehicle. Such barriers are generally designed so that the vehicle only reaches the wall in exceptional circumstances, so that damage to the vehicle and injury to the driver is minimised.

Hay bales and in particular car tyres, generally provide inadequate impact absorption for proper race track safety. The use of graded gravel or sand can provide an effective safety barrier, but the space required for the layout is not always available, particularly for street circuits, and even if it is available, the laying of the gravel or sand renders the space virtually unusable for other purposes, if the circuit is not a dedicated race track, for example if the circuit is constructed through park lands. Additionally, the effectiveness of a gravel trap can vary depending on weather conditions, and on the type of contact between the rider/car and the gravel. For example, if the rider is tumbling across the trap, or if the gravel is dry and a rider is sliding across the trap, then it will provide little retarding advantage. A different style of safety barrier is disclosed in International patent application PCT/GB95/01974, filed in the name of Recticel Limited. This is a crash barrier, which is comprised of several layers of foam each of which has different properties, to provide a gradually increasing resistance to impact. Such a barrier can be expensive due to the solid foam construction. A further style of safety barrier is disclosed in Australian patent no.

619439 in the name of Denis J. Horley. This patent discloses an air inflatable barrier that has three chambers front to rear. Upon impact with the barrier, air from the front chamber is forced into the rear chamber, while air in the middle chamber exhausts to atmosphere. The front and middle chambers decelerate the impacting body, while the third chamber stops any remaining movement of the body. A drawback with this barrier is the need for inflation and the complicated construction. Additionally, if the barrier wall is pierced, which can easily happen under impact, the inflated chamber will deflate. The wall then requires repair before the barrier can resume its normal function. It is an object of the present invention to overcome or at least alleviate the drawbacks of the prior art.

The present invention provides a safety barrier for absorbing the impact of a moving body, including a frame formed of a resiliently collapsible material and a covering formed of a flexible material extending about the frame and being supported thereby, the covering defining an internal chamber which communicates with atmosphere through an exhaust opening formed in the covering, and the pressure within said chamber being ambient in absence of an impacting body, said barrier at least partly collapsing under the influence of an impacting body, in a manner that said internal chamber reduces in volume and the pressure within the chamber increases, thus resisting further reduction in the chamber volume said exhaust opening permitting controlled exhaust of air from within said chamber under an impact. Under the influence of an impact, the covering of the barrier flexes and the frame tends to collapse and by this mechanism, the volume of the chamber is reduced. Thus, air inside the chamber is compressed and compression of the air resists further reduction in the volume of the chamber. The resistance to further volume reduction thus decelerates the impacting body. The provision of exhaust openings reduces the severity of deceleration and also prevents the barrier from springing back due to high internal pressure, such as when maximum compression has been reached. That is by allowing air to exhaust from within the chamber under an impact load, the pressure inside the chamber can be controlled, so that while it does increase, it is less likely to build to a level that prevents further reduction in the volume of the chamber. If that did occur, then upon complete deceleration of the impacting body, the pressure inside the chamber may cause it to expand rapidly and rebound the body. This is highly undesirable for racetracks, because the body may rebound back onto the track and into the path of oncoming vehicles.

The frame and the covering of the barrier perform different functions. The frame provides the structural integrity of the barrier at times other than during an impact load and the material of the frame re-establishes the shape of the barrier when the impact body has been removed from contact with the barrier. Advantageously, the barrier is such as to not require inflation to return its normal shape.

The covering of the safety barrier can take any suitable form and may for example, be a coating, such as a resin based coating or plastic coating, which is applied over the frame and that coating may adhere to the frame. Coatings of this kind may be applied by known techniques.

Alternatively, the covering may be a preformed cover that is preferably formed from a plastic or fabric material, preferably a reinforced material. Such a cover can be fitted over or about the frame, either permanently or releasably, by any known technique. The covering of the safety barrier has the effect of preventing or restricting release of air from the chamber under an impact loading. In the preferred arrangement in which exhaust openings are provided, the controlled release of air causes the impacting body to decelerate, at a rate which is determined by the size of the chamber, the impact load and by the size of the exhaust opening or openings provided. The coveπng can also assist with impact absorption, because it may have some resistance to distortion when the impact occurs, depending principally on the type of material from which it is formed and any attachment to the frame as may be provided.

The cover can also resist damage to the safety barrier through abrasion from an impacting body, particularly if the cover is formed from a reinforced fabric, such as a reinforced PVC. However, unlike inflatable barriers, small cuts which may be formed in the cover through impact with the barrier, do not necessarily affect the performance of the barrier, because the air inside the chamber is at ambient pressure and therefore will not be caused to escape from therein. A small cut may, of course, permit faster exhaust of air from within the chamber under an impact load, but that is not considered to unduly affect the barrier performance, such as to immediately require repair or replacement. Advantageously, when a cut needs to be repaired and an appropriate time becomes available for that repair, normal patching or stitching techniques can be easily adopted.

The frame can also assist with impact absorption by the choice of suitable frame material, particularly in the parts of the barrier that will normally experience reduced volume displacement under the influence of an impacting body, or alternatively, in those parts which will normally experience a concentrated impact. The lower edge of the front of the barrier is one such part that could experience either of the above described effects. However, it is the principal function of the frame to collapse under impact. It is preferable that the frame be formed of a foam material and foams such as polyurethane open cell foams can be used. These types of foams meet the requirements of flexibility and resilient collapsibility, but also have sufficient stiffness to provide some resistance to deformation of the barrier under an impact load. Such foams are of comparatively high density and hardness. The chamber of the barrier, can be of any suitable shape and volume and this may be governed by the use to which the safety barrier is put. For example, the chamber may have a greater volume when being used for motor car or motorbike racing compared with bicycle racing. The chamber can be formed in any suitable shape, but preferably an elongate chamber of generally square or rectangular cross-section is provided. The chamber is preferably defined by the covering and the frame is disposed within the chamber. In a preferred form, the chamber is generally square in cross-section, but has a top surface which has a relatively low, gable-like central peak running along the elongate length of the chamber, or otherwise sloped top so that water does not collect on the top face of the barrier.

The frame can include bracing means and that bracing means can provide structural support for the covering as well as additional facility for impact absorption. The bracing means preferably has the same characteristics as the frame and can therefore be constructed from the same or a similar material. In one arrangement, the bracing means can be formed integral with the frame such as in a certain direction, or by influencing the direction of the impacting body. The frame and bracing means (if provided) can be arranged to ensure the barrier collapses in a particular manner. For example, frame members provided at opposite ends of a barrier may be convexly and concavely shaped respectively, so that on collapse, an end of one barrier will collapse into the end of an adjacent barrier and by this mechanism, the possibility of an impacting body entering the region between adjacent barriers is significantly reduced.

The bracing means can extend in any direction within the barrier, such as widthwise or lengthwise or both.

The chamber may be separated into a plurality of sub-chambers extending along the elongate length thereof, by suitable partitioning means. The partitioning means may, for example, be formed of the same material as the frame, or as the bracing means, or may be formed of the same materials as the covering. The partitioning means may be connected to the frame and/or the covering and adjacent chambers may be in communication to enable air to exhaust from one sub-chamber to an adjacent sub-chamber under impact load. The exhaust openings may take any suitable form to promote controlled exhaust of air from within the chamber. The openings may be covered or positioned to prevent ingress of foreign matter into the chamber and they may be provided through any surface of the cover. Preferably the openings are formed in the top surface of the cover, so that they do not become covered, such as could happen if they were positioned on the rear or end surfaces of the covers, that might in use for example, abut a barrier fence, or an adjoining safety barrier. The exhaust openings might also be covered under normal operating conditions, such as by a flap.

The safety barrier can include connecting means to connect one barrier to an adjacent barrier, so as to form a chain of barriers for the appropriate barrier length required. Any suitable connecting means can be employed for that purpose. For example, straps fixed to respective barriers, such as by stitching or welding, could include a ring, and a clip to engage the ring, or snap fasteners. Alternatively, D-rings, preferably flat sided, could be attached to the respective straps and when connected, the straps can be tightened to ensure the adjoining barriers butt up against each other while the free ends of the straps can be folded back and fixed in place such as by hook and loop fasteners which would be held in shear. The connectors preferably allow adjacent barriers to abut in engagement, so as to eliminate any gaps between barriers. This is important, to minimise the potential for a body impacting in the region of abutting engagement between two barriers to penetrate between the barriers. Even if adjacent barriers abut flush against each other, under sufficient impact loading, a body may still forcibly penetrate between two barriers, and therefore, barriers of the invention which are arranged in abutting engagement, can employ a flap to cover the abutting region. Such a flap may form part of the covering of the barrier or may be separately attachable thereto. The attached drawings show an example embodiment of the invention of the foregoing kind. The particularity of those drawings and the associated description does not supersede the generality of the preceding broad description of the invention.

Figure 1 is a perspective view of a safety barrier according to one embodiment of the invention.

Figure 2 is a part sectional view of the safety barrier of Figure 1. Figure 3 shows the internal frame of the safety barrier of Figure 1. In Figure 1 the safety barrier 10 includes a cover 11 which extends fully about an internal frame that is shown in Figure 3 to define a chamber within the barrier 10. The internal frame 12 supports the cover 11 in the manner shown in Figure 1 and can take any suitable form. In one form, the frame 12 could comprise two end members 13, 14 that support the opposite ends 15 and 16 of the cover 1 1 , but that arrangement is appropriate only for barriers having a comparatively small elongate extent. For barriers having a greater elongate extent, such as that shown in Figure 1 , the frame can include bracing members 17, 18 that support the cover 11 intermediate the opposite ends 12 and 13. Like the frame, the bracing members can take any suitable form, and in Figure 3, the bracing members have the same form as the respective end members 13, 14.

In a preferred arrangement, the frame 12 of the barrier 10 includes a front frame wall 19 of 50mm thick foam extending the full length L and height H of the broad face 20 (Figure 1 ). A rear frame wall 21 of the same or similar (such as lesser) dimensions may be provided opposite the front face wall 19. Each of the members 14, 17 may be configured to form the gable-like top surface 22 of the barrier 10. For this, each member 14, 17 includes a further member 23, which is shaped to support the cover 11 in that configuration. As many bracing members 17, 18 as necessary may be provided between the ends 12 and 13 depending on the amount of support necessary for the cover 11. It is to be noted that the cover 11 fully encompasses the frame 12 and bracing members 17, 18.

Referring to Figures 1 and 2, the top surface 22 includes two openings 24 which are covered by flaps 25. Each opening 24 is covered with a fabric product 26 to prevent ingress of foreign matter when the flap 25 is withdrawn from over the opening, and the flap 25 includes hook and loop fastening portions 27, so that the flap can be moved from the open position shown in Figure 2 to a position covering the opening 24 (as shown in Figure 1 ) in which the fastening portions 27 are engaged. The flap 25 hinges about its top edge 28 which is fixed to the cover 11. The flaps 25 could equally be manufactured in other materials and for example, conveyor belt material has successfully been used, and the advantage of that material is its weight, which precludes the need to use the fastening portions 27 as required with lighter weight flaps to secure the flaps over the openings 25. It is equally possible that the flap can be secured on more than one side edge or corner and be partially open.

To connect adjacent safety barriers together, connecting means are provided in the form of connecting straps 29 and 30. The straps are each fixed at an end region of the barriers 10 and include releaseable connecting elements 31. The connecting elements 31 may simply form a snap or clip fastening that can be easily released if the barriers are to be moved.

The safety barrier 10 can be erected in any position in which impact loads are likely to be received. A broad face 20 (see Figure 1 ) is the surface against which the impact will be received and with an impact of sufficient magnitude, the air inside the chamber of the safety barrier 10 is compressed and upon sufficient compression, that air will exhaust through the openings 24. Under an extreme impact loading, the force of the air exhausting through the openings 24 will cause detachment between the fastening portions 27 so that the flap 25 will be removed from over each of the openings 24 to allow maximum air volume to exhaust through those openings. The rate at which air is released from the chamber is however controlled, by the size and number of the openings provided. The release of air also governs the rate at which the impacting bodying decelerates upon impact with the face 20, as the greater the exhaust of air the lesser the rate of deceleration. The exhaust of air from within the chamber 32 advantageously prevents the barrier 10 from springing back after the initial impact, and sending the impacting body, such as a motorbike rider, rebounding back onto the racing track. A safety barrier according to the invention provides a variety of advantages over the prior art barriers as discussed earlier. Additionally however, the safety barrier of the invention is considered to provide substantial cost savings by virtue of its simple construction. In particular, the use of exhausting air as the decellerant reduces the cost of the barrier compared to solid or semi-solid barriers, such as the barrier of Recticel Limited discussed earlier, because essentially air has no cost. The use of air does not detract from the effectiveness of the barrier of the invention, but instead, tests conducted have shown that the barrier performs as well as other known barriers, such as the barrier of Recticel Limited. A further advantage of the invention is that, when assembled, a chain of barriers and be securely formed to effectively provide a single elongate barrier area.

The invention described herein is susceptible to variations, modifications and/or additions other than those specifically described and it is to be understood that the invention includes all such variations, modifications and/or additions which fall within the spirit and scope of the above description.

Claims

CLAIMS:

1. A safety barrier for absorbing the impact of a moving body, including a frame of generally square or rectangular cross-section and formed of a resiliently collapsible material, and a coveπng formed of a flexible material extending about the frame and being supported thereby, the covering defining an internal chamber which communicates with atmosphere through an exhaust opening formed in the covering, and the pressure within said chamber being ambient in absence of an impacting body, said barrier at least partly collapsing under the influence of an impacting body, in a manner that said internal chamber reduces in volume and the pressure within said chamber increases thus resisting further reduction in said chamber volume, said exhaust opening permitting controlled exhaust of air from within said chamber under an impact and upon removal of said impacting body said frame resiliently returns said barrier to the pre-collapsed shape.

2. A safety barrier according to claim 1 , including a plurality of exhaust openings for exhaust of air from within said chamber under the influence of an impacting body.

3. A safety barrier according to claim 1 or 2, wherein said covering is a coating which is applied to the frame and which adheres thereto.

4. A safety barrier according to claim 1 or 2, wherein said covering is a separately formed cover that is fitted over said frame.

5. A safety barrier according to claim 4, said cover being formed from a reinforced plastic or fabric material.

6. A safety barrier according to claim 4 or 5, said cover being releasably fitted to said frame.

7. A safety barrier according to any preceding claim, said frame being formed substantially from a foam material.

8. A safety barrier according to claim 7, said foam material being of relatively high density and hardness.

9. A safety barrier according to any preceding claim, said chamber being elongate and having a generally square or rectangular cross-section.

10. A safety barrier according to claim 9, the top surface of said chamber being formed to slope, to prevent water gathering on that surface.

11. A safety barrier according to any preceding claim, said frame including resiliently collapsible bracing means for bracing said frame for increased resilience.

12. A safety barrier according to claim 11 , said bracing means being formed of the same or similar material as said frame.

13. A safety barrier according to any preceding claim, said chamber being formed into a plurality of sub-chambers by partitioning means.

14. A safety barrier according to claim 13, said partitioning means being formed from the same material as said frame, or said bracing means, or said covering.

15. A safety barrier according to claim 13 or 14, said partitioning means being connected to said frame and/or said covering.

16. A safety barrier according to any one of claims 13 to 15, wherein adjacent sub-chambers are in communication to permit exhaust of air from one sub-chamber to an adjacent sub-chamber under the influence of an impacting body.

17. A safety barrier according to any preceding claim, said exhaust openings being covered or positioned to prevent ingress of foreign matter into said chamber.

18. A safety barrier according to any preceding claim, said safety barrier including connecting means to connect to an adjacent safety barrier.

19. A safety barrier according to claim 18, said connecting means including adjustable straps that can be tightened to secure adjacent safety barriers together.

20. A safety barrier according to any preceding claim, including a flap provided at an end of the barrier, which in use covers the abutting region between two adjacent safety barriers.

21. A safety barrier according to any preceding claim, wherein opposite ends of said barrier are respectively shaped convex and concave, so as to permit nesting between the ends of adjacent safety barriers, so that on collapse, an end of one barrier will collapse into the end of an adjacent barrier and by this mechanism, the possibility of an impacting body entering the region between adjacent barriers is significantly reduced.

22. A safety barrier according to claim 11 or 12, said bracing means influencing the direction of the impacting body upon impact with the barrier.