FASTENING DEVICE FOR METAL SECTIONS AND OTHERWISE, AND A CRASH BARRIER EQUIPPED WITH THESE FASTENING DEVICES

FIELD OF THE INVENTION

The present invention concerns a fastening device for metal sections and otherwise, and a crash barrier equipped with these fastening devices . More in detail, the present invention concerns a fastening device to use in the assembly of metal crash barriers, commonly known by the term "guardrail"; the treatment that follows makes explicit reference to their usage, but without any loss in generality.

BACKGROUND OF THE INVENTION

As is known, at present the most widespread metal crash barriers, commonly known as "guardrails", are made of metal and consist of a series of support posts driven into the ground in a vertical position, one after the other along the edge of the road, and a series of cross-beams that are fixed to the support posts in a horizontal position, one after the other, and are also butted one to the other so as to form a longitudinal containment band that extends uninterruptedly along the side of the road, at a set height above ground. The support posts generally consist of metal sections with a U, H or L-shaped cross-section, while the horizontal crossbeams generally consist of oblong rectangular sheets of sheet metal with a W or "triple wave" cross-section, which partially overlap at the axial ends so that they can be rigidly fixed to each other at those points by means of round-headed through bolts. The rectangular sheets of corrugated sheet metaJ. are cantilever mounted to the support posts via programmed-

deformation spacer elements anchored rigidly to the support posts by means of hexagon-headed through bolts. Unfortunately, although functioning very well, the above- described crash barriers are formed by a large number of parts and therefore have particularly lengthy installation times. In fact, to be able to slow down and restrain a vehicle, guaranteeing decelerations below the limits set by homologation regulations, metal crash barriers must be carefully assembled, avoiding mechanical play between parts that could prevent the mechanical stresses deriving from the impact of a vehicle being correctly distributed over the entire structure.

A requirement that obliges installation personnel to check the tightening torque of every single bolt used in the barrier, with all the drawbacks that this involves.

The object of the present invention is therefore that of making a crash barrier that has shorter assembly times than those currently on the market . In accordance with this object, a fastening device for metal sections and otherwise is embodied according to the present invention as expressed in claim 1 and preferably, but not necessarily, in any of the dependent claims.

According to the present invention, a crash barrier is also embodied as explained in claim 8.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention shall now be described with reference to the enclosed drawings, which illustrate a non-limitative embodiment , where : - Figure 1 is an exploded perspective view of a fastening device for metal sections and otherwise, embodied according to the principles of the present invention,

- Figure 2 is a perspective view of a crash barrier embodied according to the principles of the present invention, while

- Figure 3 is a cross-section view of a detail of the crash barrier shown in Figure 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS With reference to Figures 1 and 2, reference numeral 1 indicates, in its entirety, a fastening device for the rapid anchorage of metal and non-metal sections that finds particularly advantageous utilization in the assembly of a crash barrier 2 in metal and/or a composite material, structured so as to be able to progressively absorb the kinetic energy of a vehicle should one crash into the same barrier and, if necessary, redirect said vehicle back towards the middle of the carriageway. The crash barrier 2 essentially comprises a series of vertical support posts 3 embedded in the ground, one after the other, along the edge of the road and a series of cross-beams 4 that are fixed to the vertical posts 3 in a horizontal position, one after the other at a set height above ground, and are also butted one to the other so as to form a longitudinal containment band 5 that extends uninterruptedly along the side of the road, at a set height above ground.

More specifically, in the example shown, the cross-beams 4 consist of oblong rectangular sheets 4 of corrugated sheet metal with a W or "triple wave" cross-section, which partially overlap each other at the two axial ends 4a and, with reference to Figure 3, are rigidly fixed to each other at these points by means of a series fastening devices 1 inserted such that they pass through the bodies of the cross-beams 4. With reference to Figure 2, each vertical post 3 is instead composed of a straight metal bar 6 with a U-section, which is partially embedded in the ground in a substantially vertical position, and a spacer 7 with a programmed-deformation structure that is fixed to the top end of the bar 6 so that it is in between the same bar 6 and the cross-beam 4.

More specifically, with reference to Figure 2, in the example shown, the spacer 7 essentially consists of metal strip 8 essentially bent in a C-shape and an anchor plate 9 fixed to the central segment of the strip 8 by welding. The anchor plate 9 is suitable for being fixed in a solid manner to the cross-beam 4 by means of at least one fastening device 1 (two in the example shown) , while the two ends of the strip 8 are suitable for being fixed in a solid manner on the side of the bar 6 by means of likewise number of fastening devices 1. Instead, with reference to Figures 1 and 3, the fastening device 1 comprises a metal screw 10 with a countersunk head 10a and a substantially cylindrically shaped threaded shaft 10b, a deformable tubular body 11 in cut-resistant vulcanized rubber fitted without any mechanical play onto the shaft 10b of the screw 10, a metal cap washer 12 fitted on the shaft 10b of the screw 10 between the head 10a of the screw 10 and the deformable tubular body 11 and, lastly, a metal locking cup 13 that can be screwed onto the end tip of the shaft 10b of the screw 10, with its central cavity 13a facing towards the deformable tubular body 11.

More in detail, the deformable tubular body 11 is made of cut- resistant vulcanized rubber with a hardness number of roughly 85 Shore and, in any case, between 80 and 90 Shore. It has a substantially cylindrical shape and is provided with an ogival head 11a that protrudes towards the head 10a of the screw 10 and an end hub lib of substantially cylindrical shape that projects towards the cup 13 and has an external diameter smaller than the nominal diameter of the central trunk of the deformable tubular body 11. More specifically, in the example shown, the central trunk of the deformable tubular body 11 has a nominal diameter of between 2 and 4 centimetres and is preferably, but not necessarily, equal to 2.5 centimetres, while the ogival head 11a of the deformable tubular body 11 has a maximum diameter between 3.2 and 6.4 centimetres and is preferably, but not

necessarily, equal to 4 centimetres. The overall length of the deformable tubular body 11 (i.e. including the ogival head 11a and the end hub lib) is instead between 4 and 8 centimetres and is preferably, but not necessarily, equal to approximately 6 centimetres.

With reference to Figures 1 and 3 , the washer 12 has the shape of a spherical or ogival cap and is fitted on the shaft 10b of the screw 10 with the cavity facing the ogival head 11a of the deformable tubular body 11. More in detail, the washer 12 has the shape of a spherical or ogival cap with a complementary profile to that of the ogival head 11a of the deformable tubular body 11 and is fitted on the screw 10 so as to accept and completely cover the ogival head 11a, making contact with the surface of the latter, and is preferably, but not necessarily, provided with a central countersink 12a shaped to accept the head 10a of the screw 10.

Lastly, with reference to Figure 3, the locking cup 13 has a substantially cylindrical shape and is internally shaped so that at least one segment 13a' of the central cavity 13a has a truncated-cone profile converging towards the bottom of the cavity 13a. More in detail, the larger diameter of the segment 13a' with a truncated-cone profile is greater than the external diameter of the end hub lib, while the smaller diameter of the same segment 13a' is smaller than the external diameter of the end hub lib, so that the end hub lib of the deformable tubular body 11 can penetrate inside the segment 13a' with a truncated-cone profile of the central cavity 13a, embedding itself against the walls of the central cavity 13a before coming out of the segment 13a' and reaching the bottom of the cavity, where a threaded through hole 13b is present and into which the shaft 10b of the screw 10 engages. More specifically, in the example shown, the locking cup 13 has an external diameter that is substantially equal to the nominal diameter of the central trunk of the deformable tubular body 11, while the central cavity 13a is subdivided

into two consecutive segments 13a' and 13a" with a truncated- cone profile, both converging to the bottom of the central cavity 13a.

Segment 13a' is arranged close to the entrance of the central cavity 13a of the cup 13, and is sized such that the larger diameter of the truncated cone is larger than the external diameter of the end hub lib, while the smaller diameter of the truncated cone must be smaller than the external diameter of the end hub lib. Instead, segment 13a" of the central cavity 13a constitutes the bottom of the central cavity 13a and is sized so as to connect the threaded through hole 13b with segment 13a' of the central cavity 13a. The functioning of the crash barrier 2 is identical to currently known metal crash barriers and does not need further explanation.

Instead, the fastening devices 1 are driven in by force into the specially provided through holes made in the various metal sections that constitute the crash barrier 2 - that is the oblong rectangular sheets 4 of corrugated sheet metal, the straight bars 6 with U, L or H-sections, the strips 8 and the anchor plates 9 that form the crash barrier 2 - and are then made to expand inside the various metal sections by acting directly on the screw 10 to compress the deformable tubular body 11 between the washer 12 and the cup 13.

The particular shape of the deformable tubular body 11 ensures that no metal part of the fastening device 1 can make direct contact with the metal sections, while the special shape of the washer 12 avoids the ogival head 11a being sheared off from the rest of the deformable tubular body 11 in cases where a vehicle scrapes along the longitudinal containment band 5 during impact against the barrier .

The advantages offered by the above-described fastening devices 1 are considerable: by systematically using the fastening devices 1, it is possible to drastically reduce

erection times for the crash barrier 2 and the number of personnel needed for this purpose.

The fastening devices 1 can be driven in and expanded without special precautions by a single person using rotary tools with a torque limiter, while the anchor bolts currently in use require the simultaneous presence of at least two persons and the use of manually operated torque wrenches. Finally, it is clear that modifications and variants can be made to the fastening device 1 and to the crash barrier 2 without leaving the scope of the present invention.

For example, in a different embodiment of the fastening device 1, instead of being made of metal (e.g. steel), the cap washer 12 and/or locking cup 13 could be made of Nylon or Teflon. Obviously, the washer 12 does not necessarily have to be made of the same constructional material as the cup 13.

Similarly, instead of being made of metal (e.g. steel), the sections that constitute the crash barrier 2 could be made of a composite material .