EP1561863A1

EP1561863A1 - Guardrail

Info

Publication number: EP1561863A1
Application number: EP05100752A
Authority: EP
Inventors: Adriano Fracasso
Original assignee: Metalmeccanica Fracasso SpA
Current assignee: Fracasso SpA
Priority date: 2004-02-06
Filing date: 2005-02-03
Publication date: 2005-08-10
Also published as: ITTO20040060A1

Abstract

A guardrail (1) having a longitudinal cross member (2), and a number of supporting members (3) fixed into the ground and for supporting the cross member (2) in a position substantially parallel to the ground; each supporting member (3) having a deformable body (5) structured substantially in the form of an articulated parallelogram, and which, in the event of a motorcyclist or cyclist striking the guardrail (1), is deformed controllably and gradually, so as to maintain the cross member (2) in a position parallel to itself as the cross member translates, thus gradually attenuating user impact.

Description

The present invention relates to a guardrail.

More specifically, the present invention relates to a guardrail designed to appropriately attenuate impact of a motorcyclist or cyclist against the guardrail in the event of a fall; to which application the following description refers purely by way of example.

As is known, commonly used guardrails comprise a number of metal cross or longitudinal members aligned one after the other along the edge of a road as a vehicle safety barrier; and a number of metal posts fixed vertically into the ground to support the cross or longitudinal members in the normally horizontal work position.

Guardrails of the above type are specifically designed and sized to act as a safety barrier for "large-size" vehicles, such as cars, to ensure the safety of the occupants in the event of impact against the guardrail, but constitute a potentially dangerous obstacle for motorcyclists or cyclists in the event of a fall.

Following a fall, in fact, motorcyclists or cyclists frequently skid along the road surface and crash into one of the guardrail posts along the side of the road, often incurring serious traumatic injuries. Moreover, the above hazard is further compounded in the event of impact against certain types of currently widely used guardrails, such as New Jersey or open-type guardrails having "sharp-edged" vertical posts. Needless to say, impact of a motorcyclist or cyclist against such a guardrail, even at low skid speed, could be fatal.

It is an object of the present invention to provide a guardrail designed to appropriately and gradually attenuate impact of a motorcyclist or cyclist against the guardrail in the event of a fall, and so reduce impact-induced trauma incurred by the motorcyclist or cyclist.

According to the present invention, there is provided a guardrail comprising at least one longitudinal cross member, and a number of supporting members fixed into the ground and for supporting said cross member in a position substantially parallel to the ground; said guardrail being characterized in that each said supporting member comprises a deformable body which is structured substantially in the form of an articulated parallelogram and is deformable controllably and gradually so as to maintain said cross member in a position substantially parallel to itself during its deformation.

A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 shows a view in perspective, with parts enlarged and parts removed for clarity, of a guardrail in accordance with the teachings of the present invention;

Figure 2 shows a side section of the Figure 1 guardrail in two different operating positions;

Figures 3 and 4 show sections of two variations of the Figure 1 guardrail;

Figure 5 shows a side section of a road safety system featuring the Figure 1 guardrail.

With reference to Figures 1 and 2, number 1 indicates as a whole a guardrail erected along the side of a road to gradually and controllably attenuate impact of a motorcyclist or cyclist or similar, who, in the event of a fall, skids along the road surface and crashes into guardrail 1.

Guardrail 1 substantially comprises at least one longitudinal cross member 2, and a number of supporting members 3 fixed appropriately into the ground and supporting cross member 2 in a position substantially parallel to and at a predetermined height h off the ground. In the event of impact against cross member 2 by a body of limited size and weight, e.g. a human body, supporting members 3 deform controllably and gradually to maintain cross member 2 parallel to itself and to the ground as it translates and/or is deformed.

Guardrail 1 may obviously comprise a number of cross members 2 arranged one after the other along the edge of the road (not shown), and each supported at a predetermined height h off the ground by respective supporting members 3, so as to form a substantially continuous safety strip for controllably and gradually attenuating user impact against guardrail 1.

With reference to Figures 1 and 2, each cross member 2 is set in a work position with its longitudinal axis L parallel to the ground. Supporting members 3 are located a predetermined distance apart along the edge of the road, and each comprise an anchoring plate 4 fixed to the ground by known anchoring screws or bolts (not shown); and a deformable body 5 fixed to anchoring plate 4 and connected laterally to cross member 2 to keep it in said work position.

More specifically, deformable body 5 supports cross member 2 and is structured substantially in the form of an articulated parallelogram, so as to deform controllably and gradually under the shock generated by impact of the body against cross member 2, and maintain cross member 2 parallel to itself as the cross member translates and/or is deformed.

With reference to Figures 1 and 2, in the example shown, deformable body 5 is defined by an inverted-U-shaped metal strap, which has two free bottom ends 5b anchored to anchoring plate 4 to form, with anchoring plate 4, an articulated parallelogram described in detail later on, and a top portion 5a fixed to cross member 2.

More specifically, with reference to Figure 1, top portion 5a of deformable body 5 is connected rigidly to cross member 2 by a spacer bracket 6, which is preferably, though not necessarily, made of metal or similar, and is preferably, though not necessarily, bent into a V. More specifically, spacer bracket 6 has two free ends fixed rigidly to cross member 2, and a central portion fixed rigidly to top lateral portion 5a of deformable body 5.

The free ends 5b of deformable body 5 are fixed to anchoring plate 4 by bolts 11 or similar programmed-deformation fastening systems, which, in use, in the event of impact of the body against cross member 2, deform gradually to allow deformable body 5 to translate a limited distance along the contact surface of anchoring plate 4 and so permit backup of cross member 2 from the edge of the road. In the example shown, bolts 11 fastening free ends 5b of deformable body 5 engage respective slots 12 formed in, and aligned along the longitudinal axis of, anchoring plate 4.

Deformation of bolts 11 permitting controlled translation of deformable body 5 may obviously be "programmed" in various ways, e.g. by varying the tightening torque of bolts 11 to anchoring plate 4, or by appropriately shaping slots 12 to produce local deformation of slots 12 or of bolts 11 as deformable body 5 translates along anchoring plate 4.

Cross member 2 has a substantially curved profile with a preferably, though not necessarily, constant radius of curvature, and is defined, in the Figure 1 example, by a metal strip or section of predetermined length, which may be produced by rolling or press-bending or similar.

More specifically, in the Figure 1 and 2 example, cross member 2 is defined by a substantially curved metal sheet having two stiffening ribs 13, which are fitted to supporting members 3 and extend parallel to each other and to longitudinal axis L along the whole length of cross member 2. In the example shown, the two ends of spacer bracket 6 of each supporting member 3 are fixed rigidly to respective stiffening ribs 13 by rivets, self-locking bolts or similar known fasteners.

In the Figure 1 and 2 example, cross member 2 is sized to cover each supporting member 3 on the road side, and the bottom lateral edge of cross member 2 is located at such a height h off the ground as to prevent the motorcyclist's or cyclist's body from even partly sliding beneath cross member 2, thus preventing any possible contact between the motorcyclists' or cyclist's body and supporting members 3.

Cross member 2 is therefore positioned with its bottom lateral edge at a height h of a few centimetres off the ground, so as to ensure, on the one hand, retention of the user's body, and, on the other, permit free translation of cross member 2 during impact, with no contact between the bottom lateral edge and the ground, so that the cross member is maintained in a plane substantially perpendicular to the ground as it translates and/or is deformed.

In actual use, when a motorcyclist, cyclist or similar strikes cross member 2, the kinetic energy absorbed by the cross member is transmitted partly to deformable body 5, which deforms in controlled manner, and partly to ends 5b of deformable body 5, which aid in attenuating impact by translating, parallel to direction D, along anchoring plate 4. In other words, when the body of the motorcyclist, cyclist or similar strikes cross member 2 of guardrail 1, deformable body 5 of each supporting member 3 attenuates impact by deforming gradually in substantially the same way as an articulated parallelogram structure, and by also translating along respective anchoring plate 4 in opposition to the gradual deforming action of bolts 11.

By way of example, Figure 2 shows guardrail 1 in a rest position, indicated by the continuous line, and in a withdrawn position, shown by the dash line, in which the guardrail is pushed back from the edge of the road by translation of the cross member caused by a body impacting guardrail 1.

The kinetic energy generated by impact is therefore transmitted partly from cross member 2 to the vertices of the deformable body 5 structure, which deform gradually in controlled manner in the same way as an articulated parallelogram structure, so that cross member 2 is maintained parallel to itself as it translates in direction D.

Impact is also attenuated by ends 5b of deformable body 5, which slide a given distance, parallel to direction D and in opposition to the friction exerted by slots 12 on bolts 11, thus gradually attenuating impact in controlled manner, so that cross member 2 is maintained parallel to itself as it backs up from the edge of the road.

In connection with the above, it should be pointed out that the vertices of the articulated parallelogram structure of deformable body 5 are designed for controlled, gradual deformation, so as to gradually decelerate the impacting body. Deformable body 5 of each supporting member 3 is obviously designed to attenuate impact of a body of size and weight comparable with those of a human body, and striking guardrail 1 at a predetermined speed.

In an alternative embodiment shown in Figure 3, supporting member 3 has no anchoring plate 4, and the two ends 5b of deformable body 5 are anchored directly to the ground by known anchoring screws or bolts (not shown). In this case, in the event of a body striking cross member 2, the attenuation of the impact, and therefore the moving backward of cross member 2 parallel to itself in direction D, is controlled solely by deformation of the articulated parallelogram structure of deformable body 5, whose ends 5b, as opposed to translating, remain firmly fixed to the ground in their original position.

It should be pointed out that, as opposed to comprising a U-shaped metal strap, deformable body 5 may comprise three separate straight metal segments or portions (not shown) connected in pairs at respective ends by programmed-deformation bolts to define the articulated parallelogram structure.

The advantages of guardrail 1 are obvious: it provides for controlled deceleration of the motorcyclist's body striking cross member 2, thus reducing impact-induced trauma.

Guardrail 1 may be used to advantage as a safety system for protecting motorcyclists from impacting any type of fixed obstacle along the side of the side, such as sign posts, pavements, walls, parapets, guardrails and any other type of safety barrier.

Figure 5 shows a road safety system 14, which performs the traditional function of retaining "large-size" vehicles, and also provides for appropriately attenuating impact of a motorcyclist or cyclist or similar in the case of a fall. Safety system 14, and more specifically guardrail 1, obviously provides for gradually attenuating impact not only of motorcyclists or cyclists, but also of any occupants of "large-size" vehicles thrown clear of the vehicle, in the event of a crash, and skidding across the road surface into guardrail 1.

In the Figure 5 example, in particular, road safety system 14 comprises a retaining rail 15 fixed to the ground along a section of road to retain "large-size" vehicles; and guardrail 1, which is fixed to the ground in a direction substantially parallel to retaining road rail 15. More specifically, guardrail 1 is located along the edge of the road, substantially beneath retaining road rail 15, to cover the vertical posts 16 of retaining rail 15 on the road side.

Finally, guardrail 1 has the advantage of being particularly cheap and easy to produce.

Clearly, changes may be made to guardrail 1 as described and illustrated herein without, however, departing from the scope of the present invention.

In a further variation shown in Figure 4, cross member 2 is defined by an extruded metal section in the form of a cylindrical half-shell, which preferably, though not necessarily, has a constant radius of curvature, and comprises, on the concave side, two longitudinal projections 14 having a substantially dovetailed cross section or similar, and which click onto the two ends of spacer bracket 6 of supporting member 3.

Claims

A guardrail (1) comprising at least one longitudinal cross member (2), and a number of supporting members (3) fixed into the ground and for supporting said cross member (2) in a position substantially parallel to the ground; said guardrail (1) being characterized in that each said supporting member (3) comprises a deformable body (5) which is structured substantially in the form of an articulated parallelogram and is deformable controllably and gradually so as to maintain said cross member (2) in a position substantially parallel to itself during its deformation.
A guardrail as claimed in Claim 1, characterized by comprising a ground anchoring plate (4), and fastening means (11, 12) for connecting said deformable body (5) to said anchoring plate (4).
A guardrail as claimed in Claim 2, characterized in that said fastening means (11, 12) are deformable in controlled, gradual manner, so as to permit controlled, programmed translation of said deformable body (5) along said anchoring plate (4) and by a limited amount in a first direction (D) crosswise to the cross member (2), so that said cross member (2) is maintained substantially parallel to itself as the cross member translates and/or is deformed in said first direction (D).
A guardrail as claimed in any one of the foregoing Claims, characterized in that said deformable body (5) comprises a U-shaped metal strap.
A guardrail as claimed in Claims 2, 3 and 4, characterized in that said U-shaped metal strap comprises a portion (5a) fixed to said cross member (2); and two ends (5b) fixed to said anchoring plate (4) by said fastening means (11).
A guardrail as claimed in Claim 5, characterized in that said fastening means (11, 12) comprise at least one pair of slots (12) formed in said anchoring plate (4); and respective bolts (11), each of which engages a respective slot (12) to fasten a said end (5b) to said anchoring plate (4).
A guardrail as claimed in any one of the foregoing Claims, characterized in that each said supporting member (3) comprises a spacer (6) connecting said deformable body (5) to said cross member (2).
A guardrail as claimed in any one of the foregoing Claims, characterized in that said cross member (2) is connected to each said supporting member (3) by a click-on coupling system.
A guardrail as claimed in any one of the foregoing Claims, characterized in that said cross member (2) has a substantially curved profile.
A guardrail as claimed in any one of the foregoing Claims, characterized in that said cross member (2) is defined by an extruded metal section in the form of a cylindrical half-shell.
A road safety system (14), characterized by comprising a first guardrail (15) fixed to the ground along a section of road; and a second guardrail (1) fixed to the ground, substantially parallel to said first guardrail (15) and beneath said first guardrail (15); said second guardrail (1) being as claimed in any one of the foregoing Claims.