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Title:
MOTORCYCLIST-PROTECTION BARRIER FOR ROAD GUARDRAILS
Document Type and Number:
WIPO Patent Application WO/2021/052871
Kind Code:
A1
Abstract:
Motorcyclist-protection barrier with modular structure suitable for being mounted on existing road guardrails to create a shield in the space comprised between the guardrail and the ground in order to prevent a motorcyclist from dangerously entering said space after falling from the motorcycle, said motorcyclist-protection barrier being suitable for progressively absorbing the energy of the impact caused by the motorcyclist's body.

Inventors:
MARGARITELLI FERNANDO (IT)
Application Number:
EP2020/075411
Publication Date:
March 25, 2021
Filing Date:
September 10, 2020
Export Citation:
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Assignee:
MARGARITELLI FERROVIARIA S P A (IT)
International Classes:
E01F15/04
Foreign References:
ITMC20090071A12010-10-04
EP1455020A12004-09-08
EP2395152A12011-12-14
EP1455020A12004-09-08
Attorney, Agent or Firm:
BALDI, Claudio (Viale Cavallotti 13, JESI, IT)
Download PDF:
Claims:
CLAIMS

1) Motorcyclist-protection barrier for road guardrails, comprising:

- a bracket (2) comprising an upper portion (2a) suitable for being disposed in contact and fixed to a vertical post (P) of a road guardrail, and a lower portion (2c) that is inclined by an angle (CM) relative to the perpendicular and acts as a shelf; said lower portion (2c) of the bracket (2) being elastically flexible and suitable for being spaced from said post (P); said lower portion (2c) being provided with one or more slots (23a, 23b) for fixing and supporting said motorcyclist-protection barrier (SM);

- a ribbon-like corrugated panel (1) suitable for being mounted in a horizontal sequence together with identical panels to form said motorcyclist-protection barrier (SM), said ribbon-like corrugated panel (1) being provided in cross-section with a broken line profile formed of multiple ribs (1 a, 1 b, 1 c) that are directed towards the center of the carriageway and alternated with grooves (1d, 1e), said ribs (1a, 1b, 1c) and said grooves (1d, 1e) having the profile of an isosceles trapezium with obtuse angles; wherein said panel (1) is provided at each longitudinal end with openings (A1 , A2, A3, A4) for the insertion of fixing bolts (B) used to fix said panel (1) to the end of an identical panel, and with openings (A5, A6) for the insertion of fixing bolts (B) suitable for fixing said two panels (1) in overlapped position in said slots (23a, 23b) provided on the lower portion (2c) of said bracket (2); wherein said openings (A1 , A2, A3, A4, A5, A6) for the insertion of fixing bolts (B) are disposed in said corrugated panel (1) in such a position that the heads of said fixing bolts (B) inserted in said openings (A1 , A2, A3, A4, A5, A6) are not disposed in forward position in the direction of the carriageway with respect to said ribs (1 a, 1 b, 1 c).

2) The motorcyclist-protection barrier of claim 1 , wherein said upper portion (2a) of the bracket (2) is provided with fixing means (20, 21 , 22) for fixing to the vertical post (P) of the guardrail. 3) The motorcyclist-protection barrier of claim 1 or 2, wherein said ribbon-like corrugated panel (1) comprises:

- an upper rib (1a) formed of a head section (1a’”), from the ends of which a first inclined wing (1 a’) and a second inclined wing (1 a”) branch off in symmetrical position towards the back;

- an intermediate rib (1b) formed of a head section (1b’”), from the ends of which a first inclined wing (1 b’) and a second inclined wing (1 b”) branch off in symmetrical position towards the back;

- a lower rib (1c) formed of a head section (1c’”), from the ends of which a first inclined wing (1 c’) and a second inclined wing (1 c”) branch off in symmetrical position towards the back;

- a first groove (1d) formed of a bottom portion (1 d’) comprised between said second wing (1 a”) of the upper rib (1 a) and the first wing (1 b’) of the intermediate rib (1 b);

- a second groove (1e) formed of a bottom portion (1e’) comprised between the second wing (1 b”) of the intermediate rib (1 b) and the first wing (1c’) of the lower rib (1c).

4) The motorcyclist-protection barrier according to one of the preceding claims:

- wherein said openings provided on the corrugated panel (1) for the insertion of fixing bolts (B) for fixing to a similar back panel (1 ) consist in:

• a first pair of slots (A1 , A2) that are horizontally aligned and provided in said first wing (1 a’) of the upper rib (1a)

• a second pair of identical slots (A3, A4) in symmetrical position relative to the first pair of slots (A1 , A2), which are provided in said second wing (1c”) of the lower rib (1c)

- and wherein said openings provided on the corrugated panel (1) for the insertion of fixing bolts (B) for fixing to the lower portion (2c) of said bracket (2) consist in:

• a first individual slot (A5) provided on the bottom portion (1 d’) of the first groove (1d) in intermediate position between said two slots (A1 , A2) of the pair that is obtained in the first rib (1a)

• a second individual slot (A6) provided on the bottom portion (1e’) of the second groove (1e) in symmetrical position relative to the position of the first individual slot (A5).

5) The motorcyclist-protection barrier according to one of the preceding claims, wherein the amplitude of the obtuse angles in the isosceles trapezium profile of said ribs (1a, 1b, 1c) and of the grooves (1d, 1e) of said ribbon-like corrugated panel (1) is 137°.

6) The motorcyclist-protection barrier according to one of the preceding claims, wherein said ribbon-like corrugated panel (1) is made with a sheet steel having a thickness of 1 mm and a minimum yield strength of Remin = 350 Mpa.

7) The motorcyclist-protection barrier according to one of the preceding claims, wherein said lower portion (2c) of the bracket (2) is joined at the base of said upper portion (2a) with the interposition of an intermediate portion (2b); wherein said lower portion (2c) is inclined towards the center of the carriageway and the intermediate portion (2b) is inclined with respect to the perpendicular, towards the center of the carriageway, by an angle (02) with higher amplitude than the inclination angle (a1) of the lower portion (2c).

8) The motorcyclist-protection barrier according to any one of claims 2 to 7, wherein said fixing means used for fixing to the post (P) provided in the upper portion (2a) of the bracket (2) consist in a slot with horizontal axis (22) that cuts said upper portion (2a) for approximately half of its width starting from one of the longitudinal edges.

9) The motorcyclist-protection barrier according to any one of claims 2 to 7, wherein said fixing means used for fixing to the post (P) provided in the upper portion (2a) of the bracket (2) consists in a circular hole (20) obtained in the longitudinal center line of said upper portion (2a). 10) The motorcyclist-protection barrier according to any one of claims 2 to 7, wherein said fixing means used for fixing to the post (P) provided in the upper portion (2a) of the bracket (2) consists in a pair of circular holes (21) that are vertically aligned along the longitudinal center line of said upper portion (2a).

11) The motorcyclist-protection barrier according to one of the preceding claims, wherein said openings for the insertion of fixing bolts (B) provided in said lower portion (2c) of the bracket (2) consist in a pair of slots with vertical axis (23a, 23b) aligned along the longitudinal center line of said lower portion (2c).

Description:
DESCRIPTION

MOTORCYCLIST-PROTECTION BARRIER FOR ROAD GUARDRAILS

The present patent application for industrial invention relates to a motorcyclist-protection barrier for road guardrails.

In recent years, more and more attention has been paid to the risks of motorcyclists when driving on the road.

An especially critical issue is related with the structure of traditional guardrails because said devices are mostly formed of a shaped metal ribbon supported by a plurality of strong metal posts at a certain height from the ground.

In case of fall from the motorcycle, the motorcyclist is likely to slide towards the guardrail, entering the narrow space comprised between the metal ribbon and the ground, with a high risk of severe injury because of the strong impact.

As a matter of fact, the impact and the compression may cause a severe trauma, especially in case of impact with one of the posts that support the guardrail.

In order to reduce the consequences of such a problem, guardrails have been provided with a second metal ribbon disposed in parallel position under the “main” first metal ribbon, substantially at the height of the ground, in order to close the free space where motorcyclists may enter in case of accident.

However, the motorcyclist-protection barriers of the prior art are empirical and unable to fully comply with the requirements of motorcyclists in terms of physical safety.

In fact, the impact surface with the motorcyclist’s body is too rigid and totally unable to absorb the energy of the impact.

In other instances, guardrails have a front section provided with “sharp” ribs or fixing bolts with projecting heads that can violently penetrate the motorcyclist’s body or helmet. EP1455020 discloses a motorcyclist-protector barrier for a road guardrail comprising a bracket suitable for being fixed to a vertical post of a guardrail. Such a bracket comprises:

- a vertical upper portion suitable for being fixed to the post of the guardrail;

- a lower portion with “C”-shaped configuration suitable for embracing the post of the guardrail; and

- an intermediate portion for joining the vertical upper portion with the lower portion.

Said intermediate portion of the bracket has a substantially omega shaped configuration that has elastic flexibility properties under compression, in such a way to absorb the energy of the impact of the motorcyclist’s body because of its capability to be deformed as a bellows after such an impact.

However, because of a similar configuration of the intermediate portion of the bracket, the impact surface of such a motorcyclist-protector barrier offers some resistance to flexural deformation.

The purpose of the present invention is to disclose a new motorcyclist-protection barrier suitable for being mounted on traditional guardrails and capable of solving all the aforementioned drawbacks of the prior art, reducing the risks of injury for motorcyclists who suffer a violent impact against said barrier.

In particular, the purpose of the present invention is to disclose a new motorcyclist-protection barrier with a higher flexural deformation than the barriers of the prior art.

An additional purpose of the present invention is to disclose a new motorcyclist-protection barrier provided with a progressively increasing flexural deformation.

For the sake of clarity, the description of the invention continues with reference to the appended drawings, which have a merely illustrative, not limiting value, wherein: - Fig. 1 is a partially exploded axonometric view that shows a section of a guardrail equipped with the new motorcyclist-protection barrier;

- Fig. 2 is a side view of the new motorcyclist-protection barrier and of the accessory means used to mount the new motorcyclist-protection barrier in one of the posts of the guardrail;

- Fig. 3 is an axonometric view of a first embodiment of the laminated bracket used for mounting the motorcyclist-protection barrier of the invention;

- Fig. 4 is an axonometric view of a second embodiment of said laminated bracket;

- Fig. 5 is the same as Fig. 2, except for the fact that is refers to an alternative mounting solution of the motorcyclist-protection barrier according to the invention.

With reference to the Figures, firstly, it must be noted that the motorcyclist-protection barrier (SM) according to the invention is suitable for being installed on traditional guardrails in the free space that is normally provided between the guardrail and the ground.

Reference is preferably made to guardrails formed of multiple consecutive ribbon-like corrugated metal panels (G) suitable for being supported in horizontal position by a plurality of vertical posts (P) fixed to the ground on the side of a carriageway.

With reference to said consolidated technology, it must be noted that the adjacent ends of two consecutive ribbon-like corrugated metal panels (G) are normally fixed on the surface of one of said posts (P). The new motorcyclist-protection barrier (SM) is obtained by sequentially mounting a plurality of ribbon-like panels (1 ) with an innovative corrugated profile; it being provided that such a barrier (SM) is supported in the vertical posts (P) of the guardrail by means of innovative brackets (2). With reference to Fig. 2, when seen in cross-section, said panel (1) has a broken line profile with three identical ribs (1a, 1b, 1c) disposed in the direction of the carriageway and alternated with two identical grooves (1d, 1 e); it being provided that the profile of said ribs (1 a, 1 b, 1 c) and of said grooves (1d, 1e) is an isosceles trapezium.

In particular, the consecutive sections of said broken line profile of the panel (1 ), which define said ribs (1 a, 1 b, 1 c) and said grooves (1 d, 1 e), are configured in such a way to originate an identical obtuse angle, preferably an angle of 137°, between the two consecutive sections.

With reference to Fig. 2, it can be noted that:

- the upper rib (1 a) is formed of a head section (1 a’”), from the ends of which a first inclined wing (1 a’) and a second inclined wing (1 a”) branch off in symmetrical position towards the back;

- the intermediate rib (1 b) is formed of a head section (1 b’”), from the ends of which a first inclined wing (1 b’) and a second inclined wing (1 b”) branch off in symmetrical position towards the back;

- the lower rib (1 c) formed of a head section (1 c”’), from the ends of which a first inclined wing (1 c’) and a second inclined wing (1 c”) branch off in symmetrical position towards the back;

- the first groove (1d) is formed of a bottom portion (1 d’) comprised between said second wing (1 a”) of the upper rib (1 a) and the first wing (1 b’) of the intermediate rib (1 b);

- the second groove (1 e) is formed of a bottom portion (1 e’) comprised between the second wing (1 b”) of the intermediate rib (1 b) and the first wing (1 c’) of the lower rib (1 c).

Said ribbon-like panel (1 ) is provided in each one of its longitudinal ends with six slots with horizontal axis, namely:

- a first pair of slots (A1 , A2) in horizontally aligned position is provided in said first wing (1 a’) of the upper rib (1 a)

- a second pair of slots (A3, A4) is provided in symmetrical position relative to the first pair of slots (A1 , A2) in said second wing (1 c”) of the lower rib (1 c)

- a first individual slot (A5) is provided on the bottom portion (1 d’) of the first groove (1d) in intermediate position between said two slots (A1 , A2) of the pair provided in the first rib (1a) - a second individual slot (A6) is provided on the bottom portion (1 e’) of the second groove (1e) in symmetrical position relative to the first individual slot (A5).

Moreover, it must be noted that although the preferred embodiment of said panel (1) is the one provided with said three ribs (1a, 1b, 1c) alternated with said two grooves (1 e, 1 d), an embodiment of said panel (1 ) with a different number of ribs, which are regularly alternated with said grooves, is possible.

Also in such a case, however, the upper rib is to be provided with said pair of slots (A1 , A2) in correspondence of its first wing, whereas the lower rib is to be provided with said pair of slots (A3, A4) in correspondence of its second wing.

As mentioned, a specific metal bracket (2) has been devised for mounting the motorcyclist-protection barrier according to the invention (SM), said bracket (2) having an elastically flexible laminated structure provided with a shaped profile and suitable for being fixed on a vertical post (P) of the guardrail in the direction of the carriageway.

With reference to Fig. 2, when seen after installation in a sectional view with a longitudinal plane, said bracket (2) comprises a vertical upper portion (2a) suitable for being fixed to a vertical post (P) of a guardrail, and a lower portion (2c) inclined towards the center of the carriageway relative to the perpendicular by an angle (a1). In particular, said lower portion (2c) of the bracket is suitable for being spaced from said post (P) and is elastically flexible, in such a way to act as a fit-in shelf. The lower portion (2c) of the bracket (2) is joined at the base of the upper portion (2a) with the interposition of an intermediate section (2b) inclined towards the center of the carriageway relative to the perpendicular by an angle (02) higher than the inclination angle (a1) of the lower portion (2c). Because of such a configuration of the bracket (2), the motorcyclist-protection barrier according to the invention is capable of progressively withstanding the impact of a motorcyclist’s body. In fact, after such an impact, the bracket (2) will initially offer a reduced resistance, immediately determining a high deformation of the lower portion (2c) of the bracket, and will successively offer a progressively higher resistance when the intermediate section (2b) of the bracket is deformed.

Said vertical upper portion (2a) is provided with means used for fixing the bracket (2) to a post (P), whereas said lower portion (2c) is provided with means used for fixing a motorcyclist-protection barrier (B), as illustrated below.

As shown in Fig. 3, in a first case, said means provided on the upper portion (2a) of the bracket (2) for fixing to the post (P) consist in a through hole (20) or alternately in a pair of through holes (21 ) in vertically aligned position (shown with a broken line); it being provided that all said holes (20, 21 ) are provided on the longitudinal central line of said upper portion (2a) of the bracket (2).

As shown in Fig. 4, in a second case, the means for fixing to a post (P) consist in a horizontal slot (22) that extends for half of the width of the upper portion (2a) of the bracket (2) starting from one of the longitudinal edges.

The means for fixing said motorcyclist-protection barrier (SM) consist in two slots with vertical axis (23a, 23b) in aligned position in the longitudinal central line of the lower portion (2c) of the bracket (2).

After illustrating the configuration of said panel and of said bracket (1 and 2), their cooperating modes and advantages in terms of physical protection of a motorcyclist are described.

With reference to Fig. 2, it must be noted that the installation of the motorcyclist-protection barrier (SM) provides for mounting a bracket (2) on the front of each one of said traditional vertical posts (P).

To that end, the upper portion (2a) of said bracket (2) is fitted and fixed against the side of the post (P) facing the carriageway, in intermediate position between the vertical ending edges of two ribbon-like panels (G) of the traditional guardrail, which are suitable for being fixed on the post (P). According to a preferred embodiment of the present invention, the fixing of said bracket (2) to the post (P) is obtained by means of a fixing bolt (B) with horizontal direction, which is capable of being sequentially inserted through said circular hole (20) provided on said upper portion (2a) of said bracket (2), and through a similar hole provided on the post (P) and for being finally locked in position by means of a tightening nut (D).

Successively, two consecutive ribbon-like corrugated panels (1) are fixed in said lower portion (2c) of the bracket (2).

In particular, as shown in Fig. 1 , the end of a first ribbon-like corrugated panel (1) is fitted against said lower portion (2c) of the bracket (2); then, the end of a second ribbon-like corrugated panel (1) is exactly overlapped and finally the two panels (1) are stabilized and fixed on said bracket (2).

The two ribbon-like corrugated panels (1) are overlapped and fixed by means of a first pair of fixing bolts (B) and of a second pair of fixing bolts (B).

In particular, the first pair of said fixing bolts (B) is suitable for sequentially penetrating the first pairs of slots (A1 , A2) of said two ribbon like corrugated panels (1), when said first pairs (A1, A2) are exactly aligned, and for being firmly fixed by means of a pair of tightening nuts (D).

The second pair of said fixing bolts (B) is suitable for sequentially penetrating the second pairs of slots (A3, A4) of said two ribbon-like corrugated panels (1), when said second pairs are exactly aligned, and for being firmly fixed by means of a pair of tightening nuts (D). Finally, the two ribbon-like corrugated panels (1) in overlapped position are fixed on the front of said lower portion (2c) of the bracket (2) by means of two additional fixing bolts (B), namely a first fixing bolt suitable for sequentially penetrating said first slots (A5) of the two overlapped panels (1) and the first slot (23a) provided on the lower portion (2c) of the bracket (2), and a second fixing bolt suitable for sequentially penetrating said second individual slots (A6) of the two overlapped panels and the second slot (23b) provided on the lower portion (2c) of the bracket (2); it being finally provided that also said fixing bolts (B) are stabilized in said positions by means of tightening nuts (D).

Also in such a case, the enlarged heads of the six fixing bolts (B) used for mounting the motorcyclist-protection barrier (SM) do not project dangerously from the substantially vertical plane that contains the three head sections (1 a’”, 1 b’”, 1 c’”) of the ribs (1 a, 1 b, 1 c).

Moreover, the provision of said two slots with vertical axis (23a, 23b) on the lower portion (2c) of the bracket (2) - instead of two circular holes - is justified by the fact that the provision of said slots with vertical axis (23a) permits to adjust the height of the motorcyclist-protection barrier (B) with respect to the ground.

Furthermore, the embodiment of the bracket (2) of Fig. 4, namely the one provided with said horizontal slot (22) in correspondence of its first portion (2a), can be mounted also on more traditional guardrails wherein one of the ribbon-like corrugated panels (G) is directly fixed on the front of the post (P) by means of a fixing bolt.

In such a case, for the installation of the bracket (2), it is simply necessary to loosen the fixing bolt in such a way to create a space between the ribbon-like corrugated panel (G) and the post (P), “discovering” an intermediate section of the threaded stem of the fixing bolt.

In view of the above, the upper portion (2a) of the bracket (2) can be inserted “laterally” between the ribbon-like corrugated panel (G) and the post (P), in such a way that said section of the threaded stem of the fixing bolt can be exactly inserted in said horizontal slot (22) of the bracket (2).

Naturally, after such an operation, the fixing bolt can be tightened again with its nut, in such a way to definitely lock the upper portion (2a) of the bracket (2) between the ribbon-like corrugated panel (G) and the post (P) that are brought again in mutual contact.

The advantages of the motorcyclist-protection barrier of the invention, which is obtained by assembling multiple panels and brackets (1 and 2), are described hereinafter. Firstly, it must be noted that said motorcyclist-protection barrier (SM) can progressively absorb the energy of the impact of a motorcyclist's body because it is capable of gradually rotating backwards in a controlled way, in the direction of the posts (P) of the guardrail, because of the structure and the configuration of said brackets (2).

Moreover, it must be noted that said upper portion (2a) of each bracket (2) is firmly fixed against the front surface of a post (P), whereas the intermediate portion (2b) and the lower portion (2c), which is suitable for actually supporting the barrier (SM), are devoid of constraints Likewise, it must be noted that because of its laminated structure and elastic deformation property, the bracket (2) tends to operate like an elastic contrast element with respect to the backward thrust exerted against the motorcyclist-protection barrier (SM), in correspondence of its two intermediate and lower portions (2b, 2c) that are devoid of constraints; it being also capable of generating a spontaneous return of the motorcyclist-protection barrier (SM) when the impact force ends.

In particular, said alternate “backward-forward” rotation of the motorcyclist-protection barrier (SM) is performed with respect to an axis of transverse rotation (x-x) parallel to the motorcyclist-protection barrier (SM), substantially disposed in the connection point between the upper portion (2a) and the intermediate portion (2b) of each bracket (2).

Advantageous characteristics of the invention are the result of the special structure and configuration of said ribbon-like corrugated panel (1) used for the new motorcyclist-protection barrier (SM). Advantageously, the sectional profile of said panel (1) favors the non-traumatic guided sliding movement of the helmet of the motorcyclist who hits the barrier with a non-perpendicular impact angle, along said barrier (SM).

It can be otherwise said that, in such a case, the convex profile of the helmet tends to “be inserted” in the concave profile of either one of said grooves (1d, 1e) of the ribbon-like corrugated panel (1), thus preventing an uncontrolled movement of the helmet, and consequently of the motorcyclist’s head, and avoiding an excessive stress for the neck and head vertebral joint.

More precisely, because of the specific geometry of the ribbon-like corrugated panel (1 ), the moment of inertia (Jy) of the panel (1 ), with respect to its neutral vertical axis y, is especially capable of combining resistance and deformation, thus improving safety, by using a steel sheet for the building industry (with minimum yield strength Remin = 350 Mpa) with 1 mm thickness.

Because of the low thickness of the steel sheet, on one hand, the ribbon-like corrugated panel (1 ) is especially lightweight (with a considerable saving on production costs) and, on the other hand, it can be obtained with continuous hot galvanized sheet metal, without the need for an additional hot galvanizing treatment to increase protection against corrosion.

Moreover, because of its geometry, the ribbon-like corrugated panel (1 ) suffers a plastic deformation in the point of impact with the motorcyclist that tends to flatten and compress the surface of the panel (1 ), thus increasing the surface and, most of all, the vertical height, with the double effect of restraining the motorcyclist’s body and additionally closing all passages between the lower edge of the motorcyclist-protection barrier (SM) and the ground.

As mentioned, the additional advantage of the sectional profile of the ribbon-like corrugated panel (1 ) is related with the fact that the bolts used for fixing the two panels (1 ) in overlapped position to the lower portion (2c) of the bracket (2) are not inserted in the top of one of said three ribs (1 a, 1 b, 1 c), that is to say in a position wherein the heads of said bolts would project from the impact surface of the panel (1 ), with the risk of creating dangerous “point-like” traumas of the motorcyclist’s body.

With reference to Fig. 2, it must be noted that the heads of the two fixing bolts (B) used for fixing the two overlapped panels (1 ) are disposed in non-frontal positions, whereas the heads of the two fixing bolts (B) used for fixing the motorcyclist-protection barrier (SM) to the brackets (2) are disposed on the bottom of the grooves (1d, 1e).

Finally, with reference to Fig. 5, it must be noted that the motorcyclist-protection barrier according to the invention (SM) can be also mounted in a different way.

According to such a solution, a traditional spacer (DS) for guardrails is mounted on the front of said bracket (2), which is already disposed against the post (P), said spacer (DS) being of the type used when the ribbon-like corrugated panels (G) of the guardrail are disposed in forward position, instead of being directly fixed to said post (P).

In such a case, the bracket (2) is fixed to the post (P) by means of the same pair of fixing bolts (B) in vertically aligned position used to fix the spacer (DS) to the post (P).

For such a case, it is necessary to use the embodiment of the bracket (2) provided in the upper portion (2a) with said pair of holes (21 ) in vertically aligned position, suitable for being crossed by the same pair of fixing bolts used for fixing the spacer (DS) with the front surface of the post (P). Alternatively, a bracket (2) such as the one of Fig. 4 may be used, as long as it is provided with two slots (22) disposed at a different height. In such a case, the bracket (2) must be “laterally” inserted between the spacer (DS) and the post (P), in such a way that said slots (22) receive the threaded stems of the two fixing bolts (B) used for fixing the spacer (DS) with the post (P).