WO2009144334A1 - Metal roadway safety barrier - Google Patents

Abstract

Metal roadway safety barrier formed by a series of horizontal rails, girders or fences (1) mounted on vertical posts (2) by means of a "breakable" joining mechanism (3) which provides said joint with the possibility of disengaging in a controlled manner when the level of the force transmitted thereto, following the impact of a vehicle, reaches a given value.  The "breakable" joint is formed by a screw (3) which has along its shank, at a certain distance from its head, a cross-section of lesser mechanical strength.  In an alternative embodiment, the "breakable" joint is formed by means of a "breakable" washer.

Description

 FUSE MECHANISM FOR THE SCREWED UNION BETWEEN THE HORIZONTAL FENCE AND THE VERTICAL SUPPORT POST OF METAL SAFETY BARRIERS FOR

CONTAINMENT OF VEHICLES, FOR USE IN THE MARGINS AND MEDIUM ROADS.

OBJECT OF THE INVENTION.-

The present invention relates to a fusible mechanism applicable to the bolted connection between the horizontal fences, beams or railings and the vertical support post of a metal vehicle side impact containment system or metal safety barrier, which confers on said union the ability to be released or decoupled in a controlled manner when the force acting on it, as a result of the actions produced by the impact of a vehicle against the metal safety barrier, exceeds a certain predetermined threshold value, said barrier being general safety of use on lateral and medium-sized embankments of roads and, sporadically, on road bridge board edges, containment wall crowning or similar structure.

STATE OF THE TECHNIQUE.-

There are, in practice, various types of vehicle containment systems, meaning any device installed on a road whose purpose is to provide retention and redirection to a vehicle that is outside. control, leaves the road erratic, reducing the severity of accidents, so that damage and injuries are limited both for its occupants and for the rest of the users of the road and other people or objects located in the vicinity .

One of the most common containment systems traded is metal safety barriers, used on the margins and mediums of roads. These systems have the purpose of resisting vehicle impacts by preventing them from passing through and, thereby, guaranteeing protection to third parties, allowing its redirection and controlled deceleration, so that the vehicle leaves the impact stable and continues at a speed

- reduced together with the containment system in the original traffic direction and, in this way, guarantee the safety of the occupants of the vehicle and that of other road users.

In accordance with the existing application regulations (EN 1317-2 in Europe and NCHRP 350 in the US), safety barriers and metal screens are subjected to standardized real-scale crash tests before commercial use. in the. that, in a controlled way, an impact is made between. a type vehicle and a containment system, allowing qualitative and quantitative evaluation of its behavior. A containment system successfully fulfills a crash test on a real scale when all the requirements and acceptance criteria defined in the regulations are met, in particular for the level of containment, severity of impact, deformation and exit angle, and therefore guarantees adequate security conditions, mainly for the occupants of the impacted vehicle and third parties. It is then affirmed that a containment system has the capacity to contain a certain type vehicle.

In accordance with the aforementioned regulations, a containment system (specifically designed to receive the crash of heavy vehicles such as trucks and coaches) must pass crash tests on a full scale, both of passenger cars and heavy vehicles (heavy passenger cars, trucks and coaches ), as of light vehicles (light passenger cars). This allows normal and high containment systems to also guarantee the safety of lighter vehicles, which constitute the most frequent type of accident. For example, according to European standard EN 1317-2, the normal containment level N2 requires the passing of the TB32 test (impact of a heavy tourism of 1,500 kg of weight, d 1 lOKm / h speed, and with an angle of shock against the containment system of 20 °) plus the TBl 1 test (impact of a light tourism of 900 Kg. weight, at lOOKm / h speed, and with an angle of shock against the containment system of 20 ° ). In practice, commercial containment systems present various solutions to act against the impact of both light and heavy vehicles and present the following problems:

By a Jado, in the safety barriers, all the constituent elements generally have the ability to react in a similar way and together, by deformation, before an impact of both a light and a heavy vehicle. Safety barriers designed to withstand heavy vehicle impacts (known as high containment) generally have operating mechanisms capable of responding with a different behavior to the impact of a light vehicle and a heavy one. The success in the design of such barriers consists, precisely, in the commitment to achieve good behavior in the face of two different types of impact, with the same barrier.

Safety barriers designed to resist impacts of heavy passenger cars (normal containment) generally have operating mechanisms capable of responding progressively to the impact of passenger cars with different severity index (transverse kinetic energy of impact) guaranteeing a maximum deformation 'reasonably' reduced due to the impact of a higher severity index and, in all cases, a level of severity (based on the measurement of decelerations in the vehicle during impact) sufficiently low and adequate reconduction of the vehicle at its exit.

. The basic configuration of the metal safety barriers corresponds to the union of two basic metal elements and two others, the third and the fourth, optional:

I ⁰ .- (S) fence (s) or railing (s) disposed longitudinal elements (s) horizontally in one or more levels and a predetermined height so ^• continuous, whose function is to contain and guide the vehicle It impacts, preventing it from passing through, limiting the transverse deformation and guiding it so that it can be redirected by the system in an appropriate manner. The fence can have different configurations: one or more profiles longitudinal sections of open or almost closed section, in the form of double or triple wave or in the form of "C" or "sigma", connected to the post by means of a separating element; cables or tensioned metal rods attached directly to the post; longitudinal profiles in the form of double or triple wave joined in its lower part to metal sheets with free movement capacity and calibrated to oppose a certain resistance to an impact.

2 ^or .- The post, placed vertically at regular intervals and fixed to the (s) fence (s) or. rail (s), whose function is to hold and maintain the fence (s) or rail (s) of the barrier at a certain height during the impact. The posts are generally metal profiles of section in "C", in "U", in "I", in "Sigma", in "Z", round or rectangular closed tubular sections or other type of section, which are inserted in a embankment or medium of a road so that a part of its length is embedded in the ground or through a plate with anchor bolts inserted in the ground. Before the impact of a vehicle and depending on the energy of said impact, the post deforms to a greater or lesser extent by bending and / or twisting with respect to the recess or anchoring section.

3rd.- The separating element is the intermediate connecting piece that is often arranged between a fence or rail and the post, whose function is to:

(I) join the fence or rail to the fixing posts at a certain height,

(II) act as a spacer element between said fence or rail and the post to avoid hooking on the pole of the wheel of the. vehicle during the impact against the barrier,

(III) keep the height of the fence in contact with the vehicle during the impact, compensating for the folding effect of the fence produced by the post when deforming, bending back and down, and [IV) 'attenuate or absorb part of the impact energy and contribute to the redirection of the vehicle during the impact. In the latter case, the separator is called an energy absorber. The absorber function of the separator is characteristic of high containment barriers since said barriers have a very robust or rigid basic structure, composed of the fence (s) and robust poles arranged at a short distance capable of containing heavy vehicles and, therefore, said structure is too rigid for the impact of light vehicles. The separator-absorber is specifically designed to reduce the severity of the impact of light vehicles against these rigid basic structures, softening in contact with the post and favoring the redirection of the vehicle. On some occasions, this one. element consists of a single component or an assembly assembled from metal plates and / or profiles formed in a more or less complex way, or in tubular profiles of square or rectangular section, open or closed. On other occasions, we can find barriers in which there is no separator or absorber, the fence being attached directly to the post. In other situations, especially on roads belonging to sports racing circuits, it is possible to find other arrangements in which the absorber or separator element consists of material cylinders. elastic, resistant filled with foam or similar material placed between the fences and the post or external wall; or even by a triangular semi-truss metal structure that acts at the same time as absorber and post, allowing the displacement of the barrier in case of impact. Sometimes, the • energy absorption capacity of a safety barrier is achieved by means of elastic adapters as a sheath located on the fences or railings.

4 .- A horizontal continuous rear tie that longitudinally connects the posts of the barrier at the back of the same, joining the

. consecutive posts by its upper head or consecutive separators by its rear. The strap has the function of: (I) distribute the stress caused by the impact between several posts, in order to reduce the transverse deformation of the barrier and

(II) compensate and limit the torsional stresses in the head of the posts.

The various components that constitute a metal safety barrier are assembled together, normally, by means of bolted type joints, that is, those formed by a screw or bolt with thread, an internally threaded locking nut and one or more washers.

The metal safety barriers designed for different levels of containment and, fundamentally, for the containment of passenger cars of different weights at different speeds, frequently incorporate a rigid spacer or separator element, in order to achieve acceptable levels of deformation of the barrier , as well as to maintain the stability of the vehicle during and after the impact, the severity levels within the lowest (best) class and provide it with ^: an adequate ability to redirect the vehicle at the exit. '

The typical sequence of the impact of a tourism against a metal safety barrier, of those constituted by a continuous horizontal fence supported by vertical supports, installed on the margin or median of a road, is the following:.

The initial impact between tourism and the barrier occurs between the lateral front part (left or right depending on the collision, either left or right) of tourism and the metal fence. As a consequence of this contact, the fence transmits the efforts to the nearest post which begins to deform, twisting and bending backwards. Since the impact occurs ahead of the center of gravity of the vehicle, it prints the vehicle in a redirecting direction. During this initial contact and, to a lesser degree successively, the separator [if it exists) keeps the vehicle's wheels away from the base of the post, to avoid widening. When the post depletes its deformability, from a certain angle of backward bending, it is necessary to release the joint between this post and the fence, to prevent the latter from descending vertically dragged by the post and, when a certain appearance appears height difference between the contact fence and the center of gravity of the vehicle, it is destabilized, tends to tip over or cross the barrier transversely, with the fence almost folded down. Once this connection between the post and the fence is released, the fence behaves as an element subjected to traction or "cable" transmitting longitudinal and transverse deformation forces to the posts adjacent to the "decoupled" post and thus propagating the impact on The direction of travel of the vehicle. This mechanism by which the union between the fence or the fence-separator and the post is released, is known as "fusibility." Once the first post is uncoupled by fuse, the impact spreads as the vehicle is redirected in the direction of travel, always in contact with the fence, and is decoupling, successively, the consecutive posts of the fence, which continues to work as an element subjected to traction, until the secondary impact occurs between the rear part of the vehicle and the fence, which when produced behind the center of gravity of the vehicle, prints to it a rotation in the opposite direction to the redirection stopping said redirection and producing the exit of the vehicle that separates from the system. During said exit, because the vehicle has penetrated a certain distance transversely with respect to the ^' longitudinal alignment ^' of the barrier, the last pole of the barrier in contact with the vehicle can still be disengaged. During the secondary impact, if the height of the "loose" fence in relation to the vehicle is sufficiently low, Then, the destabilization of the vehicle and the franking of the system can also occur.

The mechanism of fusibility of the barrier is normally located at the junction between the separator and the post and consists, either, of a phenomenon of "tearing" of the head of one or several screws passing through two holes of the post or of the separator, either in a progressive "cut" of sheet metal membranes that separate a series of aligned holes from each other forming part of the bolted joints, of the separator with the post or of the post with auxiliary connecting parts, or in the detachment of any part intermediate connection, etc.

In case the metal barrier does not have a separator, the only fuse mechanism that, until the present invention, has been used is that of crossing the head of the connecting screw of the fence with the post, "tearing" said head the elongated hole of the fence corresponding to this union. However, this mechanism is very poorly controllable and the loads that produce the fusibility vary and are not very repeatable.

During the impact of a tourism type vehicle, the separator fulfills its distance and maintenance function of the height of the fence in contact with the vehicle, as well as contributing to achieve a deformation of the barrier (transversal working width) as small as possible . However, the use of the separator has three drawbacks:

(i). The arrangement of a separator between the fence and the post introduces an increase in the width of the barrier that, when the berm width available for the barrier outside the roadway is reduced, creates a serious space problem and, consequently, security for traffic

(¡I). The position of the separator disposed horizontally between the fence and the pole produces a dynamic effect of "lever" on the head of the post, which distorts the transmission of efforts the fence ^'to the post, by the applied loads α lα barrier as a result of the impact against it of tourism at a certain speed. .

(iii). The arrangement of the separator implies an economic cost over the total value per execution and material of the metal safety barrier.

The use in margins and medium-sized roads of a metal barrier without separator, narrower, more robust and economical, designed specifically for the impact of passenger cars, requires the incorporation of a special type of connection between the fence and the post, capable of providing the system of the fusibility mechanism very well controlled (release of the union upon reaching a well-determined load value and do so at the instant of the sequence of appropriate impact) which, in turn, must allow obtaining an adequate response of the barrier to impact of tourism, which guarantees the following benefits:

a) That it avoids the hookings of the tourism in the decoupled posts as the vehicle deforms the barrier transversely and moves longitudinally, passing over them. For this, it is necessary that the torso-flexion deformation of the post before its decoupling of ^<

The fence is such that, once the vehicle hits said post, it has sufficiently deformed, the section of the post facing tourism being in its position of least inertia and, as a whole, the post <is already remarkably bent by embedding in the field. b) That it avoids the vertical downward drag of the fence towards the ground by the post when it deforms back and down and thus maintains the height of it in contact with the vehicle, which allows to guarantee the stability of tourism during and after impact. c) That the release of the connection between the post and the fence occurs at the appropriate time, neither before nor after, so that the loads and deformation resulting from the impact are distributed in the as many consecutive posts as possible, thus limiting the maximum transverse deformation of the barrier. If the fusibility is premature, the transverse deformation increases and the bagging of the vehicle can occur when the. transversal displacement of the same on its redirecting rotation If the fusibility is late, the fence descends excessively, dragged by the pole, the vehicle is destabilized, it can cross the barrier and also increases the maximum transverse deformation. • ^{• •}

DESCRIPTION OF THE INVENTION.-

The present invention provides a fusible mechanism for the bolted joint between the horizontal fences, beams or railings and the vertical support post of a metal safety barrier, which confers on said union the ability to be released or uncoupled in a controlled manner when The force transmitted to it, as a consequence of the actions produced in the barrier due to the lateral impact of a vehicle against it, exceeds a certain predetermined threshold value, obtaining the same technical advantages that the separating element brings to the State of the Art operation of the safety barrier but avoiding its inconveniences and, at the same time, improving its behavior by configuring, in addition, a narrower, more robust and more economical metal barrier.

For this and in order to achieve the above advantages over the

State of the Art, it has been necessary to form a new system of direct screw connection between the fence and the post of the metal safety barrier, whose main property is its controlled fuse character, both in magnitude of force and in time, which provides The following technical advantages: '

one ). It avoids the hookings of the tourism in the decoupled posts as the vehicle deforms the barrier transversely and moves longitudinally, passing over them. For this, it is necessary that the deformation to torso-flexion of the post before its decoupling of the fence is such that, once the vehicle hits against said post, it has sufficiently deformed, the section of the post facing tourism being in its position of least inertia and, as a whole, the post is already markedly bent by The recess area in the ground. 5

2). It avoids the vertical downward drag of the fence towards the ground by the post when it deforms backwards and downwards thus maintaining the height of the same in contact with the vehicle, which allows to guarantee the stability of tourism during and after the impact.

10 ^• . • - •

3). The release of the connection between the pole and the fence or "fusibility" occurs at the appropriate time, neither before nor after, so that the loads and the deformation resulting from the impact are distributed in the greatest number of consecutive posts possible, thus limiting the deformation maximum transverse of Ia

15 barrier. If the fusibility is premature, the transverse deformation increases and the vehicle can be thrown when the transverse displacement of the vehicle predominates over its redirecting rotation. If fusibility is late, the fence is excessively lowered, driven by the pole, ^one destabilizes the vehicle can reach through the barrier and also increases Ia

20 maximum transverse deformation.

The screwed fuse junction (3) of the invention described below is integrated in a metal safety barrier composed of a continuous horizontal impact element formed by one or several horizontal continuous fences or railings 25. (1), supported through said Fuse connection (3) by vertical clamping elements or vertical posts (2) inserted in the ground (4) at regular intervals, as shown in Fig. 1 and in Fig. 3.

The fusible bolted joint (3) is formed (see Fig. 4) from a 30 metal screw (5) having, along the length of the threaded rod (10) and ^'a certain distance from the head (9) of the screw , a straight section (11) or a certain area, preferably cylindrical, that has been subjected to a specific mechanical, thermal or chemical treatment, in such a way that said section (11) or zone of the screw has a mechanical resistance to breaking substantially lower α Ia of all other sections of the rest of the rod (10) of the screw (5). This section (1 1) or zone of lower mechanical resistance of the rod (10) located below the head (9) of the metallic screw (5) of connection (3) between the fence (1) and the post (2) of a metal safety barrier is called a "fuse section" and characterizes the screw (5) as a "fuse screw" and the joint (3) between fence (1) and post (2) as a "screwed fuse joint" .

This property of the fuse thyme (5) presenting a "fuse" section (1 1) of lower mechanical resistance, which is arranged a. Length of the rod (10) of the screw (5) so that, once the joint (3) is assembled between fence (1) and post (2), as indicated in Fig. 9, the fuse section (1 1) it is located, approximately, in the middle of the zone of union between them, in such a way that when a tourism impacts laterally against the barrier (see Rg. 5) the shear forces that, as a consequence of the collision, originate on the rod (10) of the screw (5) of the joint (3) between fence (1) and post (2) are concentrated, almost completely, in the section or fuse area (1 1).

In fact, when a tourism impacts laterally against the barrier by exerting a certain force on it, lateral F (see Fig. 5) this results in the appearance of a pair of opposing forces (T) on the barrier due to the fact that On the other hand, the post (2) begins to deform back and down, locked and fixed in its embedment in the ground (4) and, on the other hand, the fence (1) is pushed up by tourism. In this way, an upward force (T) acting on the fence (1) and another downward force (T) acting on the pole (2) and / the set of both forces (T) appear, subject the rod (10 ) of the connecting thyme (5) (3) of the fence (1) with the post (2) at a shear type effort.

The concentration of the shear forces caused by the impact of tourism against the barrier in a certain section (1 1) of the rod (10) of the connecting screw (5) (3) between the fence (1) and the post (2) , when presenting this section

(1 1) a lower mechanical resistance, causes and produces the breakage of the screw (5) just in said section (1 1). In this way, the behavior of the metal barrier before the impact of a tourism, presents a fusible mechanism that allows to release or uncouple the union (3) between the fence (1) and the post (2), as shown in Figure 2 Tourism laterally penetrates a certain distance in the barrier, while being redirected. and exits the system. The precise moment within the temporal sequence of the impact and the magnitude of the force at which the decoupling or fusibility occurs will be fundamental in the response of the barrier to the impact and, consequently, in its consequences. In order to achieve an adequate response, it is therefore necessary that the fuse is very controlled, predictable and repeatable. -

One of the technical advantages of the fusibility mechanism object of the present invention is that the intensity of the mechanical treatment or of the chemical treatment that is applied on the fuse section (1 1) or fusible zone of the screw, determines the final value of the mechanical resistance at break that this section or zone (1 1) presents and, therefore, the value of its difference with the nominal mechanical resistance of the screw (5). In this way, by varying the intensity of said treatment on a section or zone, the moment and the magnitude of the fusibility or uncoupling force of the joint (3), which has been described above, are achieved.

The treatment to which the section or zone (1 1) of the rod (10) of the connecting screw (5) of the fence (1) with the post (2) of the metal safety barrier is subjected, to decrease its mechanical resistance and converting it into a fuse is, preferably, a treatment of mechanical type or mechanization consisting of the execution of a cylindrical throat (12) of smaller diameter than the rod (10) of the screw (5), located at a certain distance of The head (9), as shown in Figure 6. In this case, the relationship between the diameter of the throat (12) and the diameter of the rest of the stem (10) of the screw, for a given constituent material, determines the value of the fusibility force and the difference in mechanical resistance between the section or fuse zone and the nominal screw.

A constructive variant of the mechanical fusibility treatment (see Figure 7) is the execution of one, two or more grooves (12 ') in the rod (10) of the screw (5), α a certain distance from the head (9), perpendicular to the axis of the rod (10) or slightly inclined with respect to said perpendicular. Said grooves (12 ') may all be located in the same straight section of the screw, as shown in sub-figure 7a or they may be located in different straight sections and close to each other, as shown in sub-figure 7c. In this case, the relationship between the number and depth of the grooves (12 ') and the diameter of the rest of the rod (10) of the screw, for a given constituent material, determines the value of the fusibility force and the resistance difference mechanical between the section or fuse zone and the nominal screw. -. . . .

Another constructive variant of the mechanical fusibility treatment (see Figure 8) is the execution of one, two or more notches (12 ") in the rod (10) of the screw (5), at a certain distance from the head (9), with the notch shafts perpendicular to the shaft axis (10) or slightly inclined with respect to said perpendicular. Said notches (12 ") can all be located in the same straight section of the screw, as shown in sub-figure 8a or they can be located in different straight sections and close to each other, as shown in sub-figure 8c. In this case, the relationship between the number and depth of the notches (12 ") and the diameter of the rest of the shaft (10) of the screw, for a given constituent material, determines the value of the fusibility force and the resistance difference mechanical between the section or fuse zone and the nominal screw.

The fusible connection (3) between fence (1) and post (2) achieved by means of a fusible screw (5) with a section or fusible zone (1 1) located in the rod (10) at a certain distance from the head (9 ), so that the rod (10) goes through, successively, the fence (1) through the hole (13) made therein and the post (2) through the hole (14) made therein, It is located between the fence (1) and the post (2) once the joint (3) between the fence and the post is executed, as indicated in Figure 9, you can incorporate a flat washer (6), preferably rectangular, such as Figure 13 is shown, located in the screwed connection (3) below the head (9) of the screw (5) and above the fence (1), said flat washer being pierced by the rod (10) of the screw (5) that passes through the central hole (16) made in the flat washer (6) The effect. You can also incorporate this screwed fuse connection (3) a second flat washer (7) with a central hole (17), preferably

• round, as shown in Figure 14, located between the post (2) and the lock nut (8).

The technical advantage of using these flat washers (6) and (7) in combination with a fusible screw (5) consists in their contribution to locally reinforce the fence (1) and the post (2) in the environment of the fusible joint (3) to avoid that, as a result of a vehicle impact, these elements, fence and post, are deformed locally, in the vicinity of the holes (13) and (14), respectively, that are part of the joint (3 ) with fuse screw (5). The local deformation of the fence (1) or of the post (2) around the holes (13) and (14), would consume an uncontrollable part of the stresses transmitted to the fusible joint (3) and this would damage the phenomenon of concentration of the deformation forces in the section or fusible zone (1 1) of the screw, as well as the eminently sharp nature of said forces. All this interference (dispersion

^• of transmitted efforts and loss of sharpness) would, in short, cause a disturbance in the control of the level of force and moment of fusibility of the Ia

. bolted joint (3).

The screwed fuse joint (3) between fence (1) and post (2), object of the present invention, as described above, has important technical advantages when used on a metal safety barrier configured only by a fence ( 1) continuous horizontal and vertical support posts (2) arranged at regular intervals, such as the one shown in Figure 3. Without prejudice to the above, the type of fusible joint (3) also offers the same technical advantages when Ia Metal safety barrier constituted by the fence (1) and posts (2) incorporates a rear tie rod (25) attached to the post (2) by means of a screwed connection (26), preferably non-fusible, as shown in Figure 1 1. ^'

The same technical advantages can be achieved when the type of fused screw connection (3) object of the present invention is applied to a barrier of Metal security with two fences (1) arranged symmetrically, one on each side of the post (2), as shown in Figure 12.

Finally, when it is desired to design a metal safety barrier with a level of containment slightly higher than that of tourism type vehicles, such as that corresponding to light trucks or light coaches whose center of gravity is located at a height higher than that of a tourism, it may be necessary to incorporate an intermediate piece (15) between the fence (1) and the post (2), as shown in Figure 10, so that the size of said piece is insufficient to be considered a true separator, with the sole purpose of allowing a small upward vertical displacement of the fence (1) in relation to the post (2), which is able to compensate for the imbalance between heights of center of gravity of the vehicle and the barrier, necessary to maintain stability of the first and avoid the franking of the second. In this case, both the bolted joint (3 ') between the fence (1) and the intermediate piece (15), as well as the bolted joint (3 ") between the piece (15) and the post, alternatively, can be fuses. well both unions (3 ') and (3 ") at the same time. Thus it is allowed that there is a certain upward displacement of the fence, before the decoupling of the fuse junction (3 ') or (3 ") occurs.

Another constructive alternative to achieve the controlled fusibility of the joint (3) between fence (1) and post (2), consists in the use of a fuse washer (18) instead of a screw (5) whose rod (10) has a section or fuse zone (1 1), as shown in Figure 15. The fuse washer (18) is arranged below the screw head (5) and above the fence (1) and is capable of allowing the passage of the screw head (5) through its central hole (19), from a certain level of force applied on the joint, as a result of the impact of a vehicle against the barrier.

Figure 15 shows how the ^' rod (20) "non-fuse" of said screw

(5) goes through, successively, the fuse washer (18) through its central hole (19), the fence (1) through its central hole (13), the post (2) through its hole (14), the flat washer ( 7) by its central hole (17) and the lock nut (8). DESCRIPTION OF THE DRAWINGS

Pαrα complement the description that is being made and in order to help a better understanding of the characteristics of the invention, according to a preferred example of practical realization thereof, it is accompanied as part. a member of said description, a set of drawings in which, with an illustrative and non-limiting nature, the following has been represented:

Figure 1, - Shows the straight section of a metal safety barrier, composed of a continuous horizontal fence (1) supported, by means of the screwed fuse joint (3) on a vertical post (2) inserted in the ground (4).

Figure 2.- Shows, by means of sub-figures 2a, 2b and 2c, the typical sequence 'of lateral impact of a tourism against a metal safety barrier, with fusible behavior of the junction (3) between the fence (1) and the post (2).

. Figure 3.- Corresponds to a perspective side view of a section of

^' metal safety barrier composed of a continuous horizontal fence (1) supported, by means of fused screw connections (3) on two vertical posts (2) inserted in the ground (4), these unions being constituted by a fusible screw (5) , a rectangular flat washer (6) located below the screw head, a square flat washer (7) located below the lock and tightening nut (8).

Figure 4.- Corresponds to one. Meridian longitudinal section view of a fusible metal screw (5), where the head (9), the rod (10) and the fusible section (1 1) are represented.

Figure 5.- Corresponds to a graphic representation by means of two images, 5a and 5b ^' , of the force (F) transmitted to the screw (5) of the fusible union (3) from tourism that impacts laterally against the barrier and tensions ( T) that occur on it, on the fence (1) upwards and on it. Pole (2) down, subjecting shear stress to the fuse section (1 1) of the rod (10) of the screw (5) fuse of the joint (3) between fence (1) and post (2). Figure 6.- It shows two images, sub-figure oa and sub-figure 6b, of a fusible metal screw (5) with a fusible section materialized by a cylindrical throat (12) at a certain height of the rod (10) below the Ia head (9). Sub-figure 6a corresponds to the meridian section of the fuse screw (5) and sub-figure 6b to a three-dimensional view thereof.

Figure 7.- Shows three images, sub-figure 7a, sub-figure 7b and sub-figure 7c, of a fusible metal screw (5) with a fusible section materialized by a pair of slots (12 ') executed at a certain height, of the rod (10) perpendicular to it, ^• below the head (9). Sub-figure 7a corresponds to the meridian section of the fusible screw (5) with the two slots (12 ') executed in the same section, sub-figure 7b is a three-dimensional view thereof and sub-figure 7c corresponds to Ia meridian section of the fusible screw (5) with the two slots (12 ') located in two different sections and close to each other, of the rod (10).

Figure 8.- Shows three images, sub-figure 8a, sub-figure 8b and sub-figure 8c,

¹ of a metal screw 'fuse (5) with a fuse section materialized by a pair of notches (12 ") executed at a certain height of the rod (10) perpendicular to it, below the head (9). 8a corresponds to the meridian section of the fusible screw (5) with the two notches (12 ") executed in the same section, sub-figure 8b is a three-dimensional view thereof and sub-figure 8c corresponds to

The meridian section of the fusible screw (5) with the two notches (12 ") located in two different sections and close to each other, of the rod (10).

Figure 9.- Shows two images, the sub-figure 9a in explosion and the sub-figure

9b assembled, of the screwed fuse joint between a fence (1) and a pole (2) of a metal safety barrier, composed of a fusible screw (5), characterized by its fuse section (1 1), successively going through the hole central (16) of a flat washer (6) disposed below the screw head, the central hole (13) of the fence (1), the hole (14) of the post (2) and the central hole (17) of a flat washer (7) arranged below the nut (8) for closing and tightening the joint. Figure 10.- Shows the straight section of a metal safety barrier, composed of a continuous horizontal fence (1) supported, by an intermediate piece (15), on a vertical post (2) inserted in the ground (4), being The union

(3 ') between fence and intermediate piece and / or the connection (3 ") between intermediate piece and fuse type post.

Figure 11.- Shows the straight section of a metal safety barrier, composed of a continuous horizontal fence (1) supported, by means of the screwed fuse joint (3) on a vertical post (2) inserted in the ground (4) and a continuous rear tie (25) attached to the post by means of the joint (26).

Figure 12.- Shows the straight section of a double metal safety barrier, composed of two horizontal continuous fences (1) and a vertical pole (2), arranged symmetrically one on each side of the post, and supported, both fences, on it by means of the screwed fuse connections (3), the vertical post (2) being inserted in the ground (4).

Figure 13, - Shows the three-dimensional image of a rectangular flat washer (6), of those arranged below the head of the fusible screw, with its. bore central elongated (16). ^'

Figure 14.- It shows the three-dimensional image of a square flat washer (7), of those arranged below the head of the fusible screw, with its round central hole (17). . .

Figure 15.- It shows two images, the exploded sub-figure 15a and the assembled sub-figure 15b, of the fused screw connection between a fence (1) and a post (2) of a metal safety barrier, composed of Ia combination of a non-fusible screw (5) and a fuse washer (18), passing through the rod (20) ^' of the screw, successively, the central hole (19) of the fuse washer (18) arranged below the screw head , the central hole (13) of the fence (1), the hole (14) of the post (2) and the central hole (17) of a flat washer (7) arranged below the lock nut (8) and tighten the union. EXAMPLE OF EMBODIMENT OF THE INVENTION

Figures 1, 3, 6, 9, 1 1, 12, 13 and 14 show a particular embodiment of the present invention consisting of a bolted metal connection (3) between the fence (1) and the post (2) of a metal safety barrier, formed by a metal screw (5) with a preferably round head, a flat rectangular metal washer (6) preferably located below the head (9) of the screw, another

^• flat metal washer (7) preferably square located below the

. nut, and a metal lock nut (8), whose screw (5) has in its rod (10), at a certain distance from the head (9), a section or zone (12) of diameter smaller than the diameter of the rod (10), preferably cylindrical, as a throat that is called a section or fusible zone, since it constitutes a zone of lower mechanical resistance than the rest of the rod (10) and the screw (5) that it presents in its rod (10) this area as a throat with less mechanical resistance, is called a fusible screw.

. The rod of the fusible screw (5) crosses, successively, the flat washer (6) located below the head (9) of the screw, the fence (1), the post (2), the flat washer (7) and. The nut (8) which is Ia. which closes and tightens Ia. screwed connection (3), as shown in Figure 3. Specifically, said rod (10) goes through, successively, the central hole (16) of the rectangular flat washer (6), the central hole (13) of the fence ( 1), the corresponding hole (14) of the post (2), the central hole (17) of the flat square washer (7) and the central hole of the lock nut (8) and tighten, as shown in the Figures 9. •

The position of the section or fuse zone (12) along the rod (10) of the fuse screw (5) is such that, once the joint (3) between the fence (1) and the post (definitively executed) 2), as shown in Figure 9, the section or fuse zone (12) machined in the rod (10) as a throat, is confined approximately inside the holes (13) of the fence (1) and (14) of the post (2) and it can thus be considered that the theoretical surface that separates the fence ^' (1) and the post (2) "would cut" the rod (10) of the screw (5) of union between both, in The fuse zone (12). The screwed connection (3) of the controlled fuse type, between fence (1) and post (2), is applied both to a metal safety barrier configured only from a continuous horizontal fence (1) supported by vertical posts (2) , arranged at regular intervals and inserted in the ground (4), as shown in Figure 1, as a metal barrier that incorporates, in addition to the above, one or several subsequent horizontal continuous braces (25), fixed in Ia back of the posts (2), as shown in Figure 11, or as a double metal barrier, that is, with two fences (1) arranged symmetrically on each side of the posts (2), as shown in Figure 12.

Claims

CLAIMS. 1 ^α .- Screw connection mechanism between the horizontal fence and the vertical support posts of a metal safety barrier for containment of side impacts of vehicles on margins and medium roads, which is characterized by some of the components of the bolted joint (3) between the fence (1) and the post (2) has, at least, a characteristic that gives said union (3) a controlled fuse behavior to the impact of a vehicle, so that it can be decoupled or released when the level of the force transmitted to said union (3) by the impact of the vehicle against the barrier, reaches a predetermined value. 2 .- mechanism between the horizontal screw connection fence and vertical support poles of. a metallic safety barrier Side impact vehicle sides and roads, according ^to claim I, characterized in that the screw (5) of the screw connection (3) between the fence (1) and the post (2) has, in the rod (10) and at a certain distance from the head (9) -, a section or zone (1 1) of less mechanical resistance than the rest of the screw rod (10) (5). 3 .- mechanism between the horizontal screw connection fence and vertical support poles of a metallic safety barrier Side impact vehicle road sides and, according to the preceding claims, characterized in that the section or zone (1 1) of lower mechanical resistance has been achieved from a screw (5) that had the same mechanical resistance throughout the entire rod, by means of the application of a specific mechanical, thermal or chemical treatment applied in that section or zone (1 1). 4 ^a. - Mechanism of union bolted between the horizontal fence and the vertical support posts of a metal safety barrier for containment of lateral impacts of vehicles on margins and medium roads, according to the preceding claims, characterized in that the screw ( 5) of the union bolted (3) between the fence (1) and the post (2), in the stem (10) and at a certain distance from the head (9), a section or zone (12) as a throat, preferably cylindrical, of smaller diameter than the rest of the rod (10). 5 .- mechanism between the horizontal screw connection fence and vertical support poles of a metallic safety barrier Side impact vehicle sides and roads, according ^to claims I, 2 and 3, characterized in that the screw (5) of the screwed connection (3) between the fence (1) and the post (2) has, in the rod (10) and at a certain distance from the head (9), one or more grooves (12 ') perpendicular to the axis of the rod (10) or slightly inclined with respect to the perpendicular to the axis of the rod (10), preferably all of them (12') in the same straight section thereof (10). 6 ^a. - Mechanism of union bolted between the horizontal fence and the vertical support posts of a metal safety barrier for containment of lateral impacts of vehicles on margins and medium roads, according to claim 5 ^a , characterized in that the grooves (12 ') in the rod (10), perpendicular to the axis of the rod (10) or. slightly inclined with respect to Iq perpendicular to the axis of the rod (10), they are located in two or more straight sections other than this, preferably close to each other. 7 ^a - Screw connection mechanism between the horizontal fence and the vertical support posts of a metal safety barrier for containment of side impacts of vehicles on margins and medium roads / according to claims I ^a , 2 ^a and 3 ^a , which It is characterized in that the screw (5) of the screwed connection (3) between the fence (1) and the post (2) has, in the rod (10) and at a certain distance from the head (9), one or more notches ( 12 ") with an axis perpendicular to the axis of the rod (10) or slightly inclined with respect to the perpendicular to the axis of the rod (10), preferably all of them (12") in the same straight section thereof (10). 8 ^a , - Screw connection mechanism between the horizontal fence and the vertical support posts of a metal • safety barrier for impact containment side of vehicles on margins and medium roads, according to claim 7 ^a , characterized in that the notches (12 ") in the rod (10), perpendicular to the axis of the rod (10) or slightly inclined with respect to the perpendicular to the shaft of the rod (10), they are located in two or more straight sections other than this, preferably close to each other. 9 ^a. - Mechanism of union bolted between the horizontal fence and the vertical support posts of a metal safety barrier for containment of lateral impacts of vehicles on margins and medium roads, according to the preceding claims, characterized in that the section or zone (1 1) (12) (12 ') (12 ") of lower mechanical resistance of the screw (5) of the bolted joint (3) between the fence (1) and the post (2), is located in a certain position along the rod (10) of the screw (5) and at a certain distance from the head (9) of the latter in such a way that , once the screwed connection (3) is executed, the section or fuse zone (1 1) (12) (12 ') (12 ") is located, simultaneously, inside the hole (13) of the fence (1) and the hole (14) of the post (2), both holes (13) and (14) corresponding to said joint (3). 10 ^a. - Mechanism of union bolted between the horizontal fence. And the vertical support posts of a metal safety barrier for containment of lateral impacts of vehicles on margins and medium roads, according to the preceding claims, which is characterized in that the union screwed (3) between fence (1) and post (2) incorporates a flat washer (6); preferably rectangular, located just below the head (9) of the screw (5) and above the fence (1). 11 .- mechanism between the horizontal screw connection fence and vertical support poles of a metallic safety barrier Side impact vehicle road sides and, according to previous claims, characterized in that the screw connection (3) between fence (1) and post (2) incorporates a flat washer (7), preferably square, rectangular or round, located just below the lock nut (8) and above the post (2). 12 ^a. - Mechanism of union bolted between the horizontal fence and the vertical support posts of a metal safety barrier for containment of lateral impacts of vehicles on margins and medium roads, according to the preceding claims, characterized in that said union ( 3) is applied to a metal safety barrier formed solely by a continuous horizontal fence (1) supported by an alignment of vertical posts (2), arranged at regular intervals and inserted into the ground (4). 13 .- mechanism between the horizontal screw connection fence and vertical support poles of a metallic safety barrier Side impact vehicle road sides and, according to previous claims, characterized in that said joint ( 3) It is applied to a metal safety barrier formed by a continuous horizontal fence (1) supported by an alignment of vertical posts (2), arranged at regular intervals and inserted into the ground (4) and one or more braces (25) rear set (26) on the posts (2) 14 .- mechanism between the horizontal screw connection and fence posts • vertical support of a metal, safety barrier for containment of ^' lateral impacts of vehicles on roadsides and medium-sized roads, according to the preceding claims, characterized in that said union (3) is applied in a metallic safety barrier formed by two Symmetrical horizontal continuous fences (1) supported by an alignment of vertical poles (2), arranged at regular intervals and inserted in the ground (4) and located the two fences (1) symmetrically one on each side of the post (2). 15 .- mechanism between the horizontal screw connection fence and vertical support poles of a metallic safety barrier Side impact vehicle road sides and, according to previous claims, characterized in that the barrier incorporates a small intermediate piece (15), arranged between the fence (1) and the post (2), the fused screw connection being made well (3 ') between the fence (1) and the intermediate piece (15), either (3 ") between the intermediate piece (15) and the post (2) or • well in both joints (3 ^' ) and (3 "). 16 .- mechanism between the horizontal screw connection fence and vertical support poles of a metallic safety barrier Side impact vehicle sides and roads, according to claim 1, characterized in that the binding Screwed between the fence (1) and the post (2) incorporates a fuse washer (18), preferably "U" shaped section, located below the head of the screw (5) of the union and above the Ia fence (1), be able to be completely crossed by the screw head (5) when the force applied in the union as a result of the impact of a vehicle, exceeds a certain value, thus decoupling the union between fence (1) and post ( 2).