EP0807195A1

EP0807195A1 - Roadside crash barrier with a shock-absorbing device

Info

Publication number: EP0807195A1
Application number: EP96902326A
Authority: EP
Inventors: Pascal Rambaud
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-02-01
Filing date: 1996-02-01
Publication date: 1997-11-19
Anticipated expiration: 2016-02-01
Also published as: FR2729980A1; WO1996023933A1; ATE179476T1; DE69602253T2; DE69602253D1; FR2729980B1; ES2130792T3; EP0807195B1

Abstract

A roadside crash barrier with shock-absorbing devices (3) arranged between the crash barrier rail (1) and the supporting posts (2). Each shock-absorbing device comprises two arms (3A, 3B) arranged in a V and designed to spread apart when a force is exerted on the rail, while absorbing the related energy by means of friction between the movable parts, and optionally by plastic deformation.

Description

"Road safety barrier with shock absorbing device"

The present invention relates to the field of safety barriers, which, generally consisting of a profiled rail mounted on vertical supports stuck in the ground, are arranged on either side of a road. These may be slides protecting a conventional road, a motorway, or, more particularly, a racing circuit. Generally, the rail of such a slide has a coated W section, and its vertical supports are U or C section profiles.

These slides have the particular function of preventing exits from the road, and, for vehicles striking them with a sufficiently low angle of incidence, to replace them on a path parallel to the roadway, by sliding the vehicle against the rail. .

However, when a vehicle hits these runners too violently, with too large an angle of incidence, two types of problems arise:

- first of all, the slides will restore part, absorbed by elastic deformation, of the kinetic energy of the impact, which, returning the vehicle to the roadway, puts the latter at risk of collision with another vehicle;

- Then, the plastic deformation of the slide, by which the rest of the impact energy is dissipated, generally results in a tilting of the vertical supports, which lie down, and in a depression of the rail by bending between two vertical supports.

It results from such plastic deformation of the slide a modification of its geometry very damaging to the efficiency of the structure, the deformation by driving in the rail causing an off-center guide effect which promotes the sudden return of the vehicle to the roadway, and the tilting of the assembly reducing the protective height, which can, at the limit, give the work a springboard effect.

It has been proposed to add shock absorbing means to the slides, to, at least, limit the drawbacks which have just been mentioned. Thus, for example, it has been proposed to have deformable plastic bodies in front of the rail, forming shock absorbers.

However, such an arrangement, described, for example, in European patent No. 90830612, harms the primary function of the rail which is to allow the sliding of a vehicle striking it with a small angle of incidence. In addition, this arrangement is expensive and complicated to implement.

It has also been proposed to interpose deformable parts between the rail and its vertical supports.

The known deformable parts, described, for example, in French patents Nos 71 41 899 or 73 03 150, allow only slight deformations. They are therefore not suitable for absorbing violent shocks, as is the case, for example, on automobile circuits.

In addition, the resistance to crushing of these parts decreases during deformation, which does not meet the safety needs of the driver of the motor vehicle hitting the slide. The present invention relates to a shock absorbing device, interposed between each vertical support and the rail, adapted to deform sufficiently to allow a sufficiently gentle damping of said shock, while not giving rise to a tilting or depression of the rail. For this purpose, a road safety barrier is provided provided with shock energy absorbing devices intervening between a slide rail and its vertical supports, each of said absorbing devices being characterized in that it comprises two arms which, starting from the vertical support, are arranged substantially in a V, in a horizontal plane, their free ends carrying the rail, said arms being adapted to open, under the effect of a constraint -

applied to the rail, thereby absorbing the energy associated with said stress.

The opening of the arms absorbing the energy of a constraint applied to the rail, for example the impact of a motor vehicle, this constraint is not likely to cause a tilting of the vertical supports nor a depression of the rail between two posts, said rail only getting closer to its vertical supports under the effect of the applied stress. In addition, when a vehicle hits the rail with a not too large angle of incidence, the slide will keep, to some extent, its deflector function. Indeed, and as will be better understood later, the rail, which, not being strictly subject to its vertical supports, can deform regularly, first bends so as to extend parallel to the direction of incidence of the vehicle, then gradually return to a position parallel to its initial position. This, authorizing the sliding against the rail of the vehicle, makes it possible to bring this last in the axis of the road.

The characteristics and advantages of the invention will emerge from the description which follows, with reference to the accompanying drawings, among which: - Figure 1 is a perspective view of a road safety barrier according to the present invention, - Figure 2 is a sectional view, along the direction II-II of the slide of Figure 1; Figure 3 is a sectional view, along the direction III-III of the slide of Figure 1;

- Figures 4 and 5 are schematic views of the slide shown in the previous figures, showing its shape respectively before and after the application of a stress; - Figures 6 and 7 are schematic views of a first alternative embodiment of a slide according to the present invention, showing its shape respectively before and after the application of a constraint;

- Figures 8 and 9 are schematic views of a second alternative embodiment of a slide according to the present invention, showing its shape respectively before and after the application of a stress; and

- Figure 10 is a view showing the deformation of a slide according to the second alternative embodiment of the present invention, when a motor vehicle strikes it.

Figures 1 to 5 show a first example of a road safety barrier according to the present invention.

This slide comprises, in a known manner, a rail

1, in practice consisting of two coated W profiles arranged one above the other.

This rail is carried by vertical supports 2 inserted into the ground, here posts of rectangular section, as seen in FIG. 1.

According to the invention, between each post 2 and the rail 1 is interposed a device 3, shock energy absorber, comprising two arms 3A and 3B which, starting from the post 2, are arranged substantially in a V, in a horizontal plane, their free ends carrying the rail.

Advantageously, and as shown in FIGS. 1 to 3, the arms 3A and 3B are profiles of the same section as the slide rail, here a pair of coated W profiles arranged one above the other.

Of course, these arms may have sections different from those of the rail 1, provided that they have good resistance to vertical stresses, so that they can only deform in the horizontal plane in which they are extend.

Such a device 3 must be able to absorb most of the energy from the impact of a motor vehicle on the rail, so that the latter is not, at least, not bent by bending between two posts or tilted by post deformation 2.

According to the invention, this energy absorption takes place by opening the arms 3A and 3B, so that the slide does not deforms only by bringing the rail 1 towards the posts 2. According to one aspect of the invention, as can be seen in FIG. 1, the arms 3A and 3B are constituted by the two ends of the same curved profile, at least part of the absorption of impact energy being by plastic deformation at the elbow of said profile.

Advantageously, the initial opening angle of the arms 3A and 3B is of the order of 45 °. Indeed, the withdrawal of the rail 1 towards the post 2, in this case, is substantially proportional, at least initially, to the variation in the opening angle of the arms. In other words, the resistance to deformation of the slide remains constant during the movement, and, consequently, the absorption of energy takes place regularly or gradually during the movement of opening of the arms.

As can be seen in FIG. 1, in the example shown, the fixing on a post 2 of the curved profile 3, forming an energy absorption device, is done by means of bolts 10 passing through the bent part of said profile . To prevent the opening of the arms 3A and 3B from exerting traction on the rail 1, it is necessary either to use telescopic arms or to provide a degree of freedom at the connection between said arms and said rail . Thus, in the embodiment shown in FIGS. 1 to 5, the ends of the arms 3A and 3B are slidably mounted longitudinally along the rail 1.

More specifically, as can be seen in FIGS. 2 and 3, longitudinal slots 9 and 8 are formed on the flat central parts, respectively 20 and 21, of the rail 1 and of the arms 3A and 3B. Two slots 9 are provided, one above the other, on the free ends of the arms 3A and 3B, each of these slots being aligned with a slot 8 of the rail 1. Two hooking devices 11 are associated with each pair of aligned slots 8 and 9. Each of these devices comprises, as can be seen in FIGS. 2 and 3, a threaded rod 5 at the two ends of which bolts 6 are installed, said threaded rod passing through the slot of one of the parts of the sliding assembly as well as a bore of the other part formed in alignment with the own slot of the latter.

In other words, one of the attachment devices 11 is integral with the rail 1 and slides in a slot 9 of the curved profile 3, while the other device 11 is integral with the end of the arm of the profile 3 in which is formed said slot 9, and slides in the corresponding slot 8 of rail 1.

As can be seen in FIG. 3, in the initial position, the hooking devices 11 are each in abutment against one end of the corresponding slot, the slot 9 extending, from the device 11 which passes through it, towards the post 2, while the slot 8 moves away, from the device 11 which passes through it, from this post 2.

The end of each of the arms 3A and 3B can therefore only slide on the rail 1 away from the post 2.

Thus, the freedom of sliding of the arms relative to the rail is limited to the freedom that the arms 3A and 3B have of deviating from one another.

In this way, the arms 3A and 3B actually carry the rail 1 while being able to move away from each other freely, without exerting any stress on the latter. According to another aspect of the present invention, the absorption of impact energy is effected, at least in part, by the interposition of friction or braking means between the parts mounted to slide relative to the 'other, that is to say, in the embodiment shown in Figures 1 to 5, the free ends of the arms 3A and 3B and the rail 1.

Advantageously, and as is the case in the example shown in Figures 1 to 5, this means of absorbing the impact energy is associated with that described above. This association is to be preferred because it presents a good efficiency / cost ratio, it facilitates the adjustment of the braking coefficient of the slide, and, finally, it makes it possible to best avoid any undesirable elastic deformation.

However, it is conceivable to use the latter means of absorption alone, the arms 3A and 3B having to be, in this case, pivotally mounted on the post 2.

Anyway, Figures 2 and 3 show an example of arrangement implementing such a friction means between two sliding parts relative to each other. Friction plates 12 and 14 are fixed on, respectively, one and the other of the parts 1 and 3 of the sliding assembly, at the level of the respective flat central parts 21 and 20 of the latter, so as to be in contact with one another, between said parts 1 and 3 of the sliding assembly, as can be seen in FIG. 2.

Advantageously, a pair of plates 12 and 14 is associated with each pair of aligned slots 8 and 9. As can be clearly seen in Figures 1 to 3, the plates 12 and 14 of such a pair are aligned with the slots 8 and 9 corresponding, an end portion of the plate 12 lying opposite an end portion of the plate 14.

As seen in FIG. 3, slots 13 and 15 are provided in the plates, respectively, 12 and 14, in the extension of the slots, respectively, 8 and 9.

Bores are provided in the plates 12 and 14, so as to allow the rods 5 of the hooking devices 11 to pass through.

The bolts 6 of the attachment devices 11, with which are associated elastic washers 16 with axial action, are tightened with a determined torque. The fastening devices 11 then play the role of means adapted to clamp one against the other, with an adjustable force, the two parts of the sliding assembly. The contact between the sliding parts 1 and 3 is made, in fact, by means of the plates 12 and 14, which will rub against each other during sliding. This friction dissipates a certain amount of impact energy into heat.

If the friction force at the level of the sliding assembly is constant throughout the relative movement of the two parts 1 and 3 of this assembly, given that the ratio between this movement and the displacement of the rail 1 towards the post 2, it , decreases, the resulting braking effect will be decreasing.

This is why, according to one aspect of the invention, the friction means 12 and 14 interposed between the two parts of the sliding assembly progressively brake the relative movement of these sliding parts.

For this purpose, and as can be seen in FIG. 3, the plates 12 and 14 have a wedge shape, the thickness of each of them increasing as one moves away from the end facing the other room.

Thus, as the two parts of the sliding assembly move relative to each other, the friction force at the level of the sliding assembly will increase.

The slope of the active surfaces of the plates 12 and 14 is, of course, chosen so as to compensate for the degressive braking effect, so that the energy absorption takes place regularly, or even gradually, during the movement of arms opening. In addition, the shapes of these plates 12 and 14 are chosen to be complementary, so that they extend one against the other throughout the movement.

The example shown in Figures 1 to 3 corresponds to the particular case of rails formed by the association of two coated W profiles arranged one above the other.

In such an arrangement, and for safety reasons, the displacements of the two coated W-shaped profiles will be secured, for example by interposing a plate, either between said profiles, or, advantageously, between the corresponding profiles of the absorption devices. 3. Figures 6 and 7 show an alternative embodiment of the present invention.

In this variant, the arms 103A and 103B are telescopic. Each of these arms therefore comprises two sliding parts relative to each other.

The opening of the arms 103A and 103B is therefore possible, without modifying the interval separating the attachment points with the rail 101, by reducing the length of these arms, as can be seen in FIGS. 6 and 7. Advantageously, the ends of the arms 103A and 103B will be mounted on vertical axes integral with the rail 101, so that these arms can freely pivot in the horizontal plane in which they extend.

Such an alternative embodiment will advantageously be implemented when the spacing between the support posts of the rail is small and that, consequently, it is preferable that the interval separating the attachment points with the rail remains constant.

Of course, friction means such as those described above may be interposed between the two sliding parts of each of the arms, in order to absorb, at least in part, the energy of the impact.

Figures 8 and 9 show a second alternative embodiment of the present invention. This variant corresponds, in fact, to the variant of FIGS. 6 and 7, an additional absorbing device 213, comprising two additional arms 213A and 213B, being associated with the absorbing device 203.

These additional arms 213A and 213B, starting from the vertical support 202, are arranged substantially in a V, open in the other direction than that formed by the arms 203A and 203B, the free ends of these additional arms being connected to the rail by crosspieces 210 , perpendicular to the latter. Friction means, such as those described above, are interposed between the two sliding parts of each of the arms 213A and 213B, as well as each of the arms 203A and 203B.

As can be seen in FIGS. 8 and 9, when the arms 203A and 203B open, the rail 201 approaching the friend 202, the arms 213A and 213B will close, thus also absorbing a certain energy, by braking effect.

As we have seen, if the friction force, at the level of the sliding assemblies, is constant throughout the long opening movement of the arms 203A and 203B, the braking effect, at the level of the absorbing device 203, decreases.

On the other hand, this braking effect, at the absorber device level 213, will be progressive.

The initial openings of the respective arms of this absorbing device 203 and 213 will therefore be chosen so that the decreasing braking of one is compensated by the progressive braking of the other.

This alternative embodiment therefore avoids having to implement braking means with progressive effect such as those described in the first embodiment. In another alternative embodiment, said additional bra 213A, 213B being used only in tractio during the absorption of the impact energy, it is possible to replace each arm 213A, 213B by a cable associated with u equivalent braking means by means of friction 12, 14 of FIGS. 2 and 3.

FIG. 10 shows, schematically, the deformation of a slide according to the second variant described, when a motor vehicle hits the rail 101 with a not too large angle of incidence. The rail 101, not being subject, strictly, to its vertical supports 102, can be deformed in a regular manner, without driving effect due to the reaction of the posts. It therefore bends, at the point of impact, so as to extend parallel to the direction of incident of the vehicle, then, as one moves away from the point of impact, returns gradually in a positio parallel to its initial position. Of course, this deformation of the rail is done by always approaching the posts 102, which allows the absorption of impact energy. As can be seen in FIG. 10, the regular deformation of the rail 101 allows the vehicle to slide against it, making it possible to bring the latter back into the axis of the road.

It should be noted that the V-shaped arrangement of the arms of the shock energy absorption devices makes it possible to best combat the risk of longitudinal drive of the rail relative to its supports, when a vehicle, in particular a passenger car Formula 1 type sport, rolls against said rail.

Another advantage provided by the present invention comes from the fact that only the shock energy absorption devices and, to a lesser extent, the rail, undergo deformations following an impact. The support posts are spared. This makes it much easier to replace the slides having suffered a significant shock. It should also be noted that the impact energy absorption devices according to the invention which have just been described can be easily installed on the rails equipping, at present, the road network or the automobile circuits.

Claims

1. Safety barrier of the kind comprising, between a slide rail (1) and vertical supports (2), shock absorbing devices (3) constituted by deformable elements comprising on either side of a central zone of support on the vertical supports (3) of the arms ending in sliding support zones on the slide rail

(1), characterized in that said deformable elements are sections of curved V-shaped profile (3A, 3B) on either side of an elbow zone and connecting to the slide rail (1) with interposition of means of friction (12, 14) adapted to maintain at least constant the absorption of impact energy taking place by friction within a limit of elastic deformation and continuing by plastic deformation of said elbow zone in the event of exceeding this limit.

2. Safety barrier according to claim 1, characterized in that the friction means (12, 14) are interposed between said end support zones and the slide rail (1) and comprise wedge parts, adapted to absorb gradually impact energy.

3. Safety barrier according to claim 2, characterized in that said end support zones and the slide rail (1) are associated with means (11) adapted to clamp them one against the other with a force. adjustable.

4. Safety barrier according to any one of claims 1 to 3 characterized in that the arms (3A, 3B) of the absorber device (3) consist of a curved profile, of the same section as the slide rail.

5. Safety barrier according to claim 1 characterized by deformable elements (103) with telescopic arms (103A, 103B), the friction means being interposed between the sliding parts of each arm.

6. Safety barrier according to claim 5 characterized in that each absorbing device comprises two additional arms (213A, 213B) which, starting from the vertical support, are arranged substantially in an open V in the other direction than that formed by the other two arms (203A, 2Q3B), free ends of these additional arms being connected to the rail (201) by crosspieces (210) perpendicular to the latter.

7. Safety barrier according to claim 6 characterized in that each additional arm (213A, 213B) is replaced by a cable associated with a braking means.