ES2535496T3 - Metal safety barrier with a fusible mechanism for the screw connection that connects its horizontal fences and vertical support posts, which is used on the margins and mediums of roads for vehicle containment - Google Patents

Abstract

Metal safety barrier for use on the margins and medians of roads for containment of vehicles comprising at least one horizontal fence (1) and a series of vertical posts (2), said fence (1) having a series of holes (13) , each of said posts (2) having a hole (14), said barrier being the type that contains side impacts of vehicles with a controlled decoupling of fence (1) and post (2) according to a preset decoupling threshold value, characterized because said barrier comprises a screwed connection mechanism of fence (1) and post (2), said joining mechanism comprising a screwed fuse (5), said screw (5) having a rod (10), said rod having (10) ) a zone (11) of lower mechanical resistance (11, 12, 12 ', 12 ") than the rest of the rod (10), said zone of lower mechanical resistance being located at a certain distance from the screw head (9) and in a position such that, once the screwed connection (3) is executed, said section that has lower mechanical resistance (11, 12, 12 ', 12 ") is placed, both, inside the hole (13) of the fence (1) and the hole (14) of the post (2).

Description

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DESCRIPTION

Metal safety barrier with a fusible mechanism for the screw connection that connects its horizontal fences and vertical support posts, which is used on the margins and mediums of roads for vehicle containment

Object of the invention

The present invention relates to a metal vehicle restraint system designed to contain side impacts of vehicles or metal safety barrier with a fusible mechanism, applicable to bolted joints that connect their horizontal fences, beams or railings to their vertical support posts. , which gives said joint element the ability to release or disengage in a controlled manner when the force acting on it, as a result of the impact of a vehicle against the metal safety barrier, exceeds a preset threshold value, said barrier being safety of the type that is generally used on lateral and medium-sized embankments of roads and, occasionally, on the edges of bridge boards, coronation of retaining walls or similar road structures.

State of the art

In practice, several vehicle restraint systems are used, understanding as such any device installed on a highway whose purpose is to provide means of retention and reorientation for vehicles that, out of control, run out of course on the road. These devices reduce the severity of accidents caused in this way, limiting damages and injuries both to the occupants of the vehicle and to other road users and other people or objects standing or located nearby.

One of the most common containment systems, from a commercial point of view, is the metal safety barrier, a device that is used on the margins and medians of roads. These systems are designed to resist vehicle impacts while preventing the vehicle from crossing the barrier and, therefore, guarantee the protection of third parties, allowing a controlled reorientation and deceleration of the colliding vehicle, so that the vehicle can get out of the impact in a stable manner and can continue your gear at a reduced speed next to the containment system and in the original direction of the gear and the lane through which you were traveling and, therefore, ensure the safety of the occupants of the vehicle and of other road users.

In accordance with current regulations (EN 1317-2 in Europe and NCHRP 350 in the US), safety barriers and metal screens are subject to standardized real-scale crash tests prior to commercial use. During these tests a vehicle collides in a controlled manner against a containment system and then the behavior is assessed qualitatively and quantitatively. The behavior of a containment system is considered satisfactory when all the requirements and acceptance criteria established in the regulations corresponding to a real-scale crash test are met, in particular, in terms of level of containment, severity of impact, deformation and angle of departure and, therefore, guarantees adequate safety conditions, mainly for the occupants of the impacting vehicle and for third parties. It is then claimed that a containment system is capable of containing a specific type of vehicle.

According to the regulations mentioned above, a containment system (specifically designed to receive the crash of heavy vehicles, such as trucks and coaches) must pass the full-scale crash tests corresponding to both passenger cars and heavy vehicles (heavy passenger cars) , trucks and coaches), as well as crash tests corresponding to light vehicles (light passenger cars). This allows high and normal containment systems to also guarantee the safety of lighter vehicles, which are the vehicles that are most frequently involved in accidents. For example, according to European standard EN 1317– 2, the normal containment level N2 requires that the barrier passes the TB32 crash test (impact of a 1500 kg heavy tourism that travels at a speed of 110km / h impacting the containment system with a shock angle of 20º) plus the TB11 test (impact of a light tourism of 900 kg that travels at 100km / h speed impacting the containment system with a shock angle of 20º).

In practice, commercial containment systems offer several solutions against the impacts of both light and heavy vehicles and have the following problems:

On the one hand, all the elements constituting safety barriers generally have the ability to react in a similar way and together, deforming to the impact of a light or heavy vehicle. Safety barriers designed to withstand heavy vehicle impacts (known as high containment barriers) generally have operating mechanisms capable of responding differently to the impact of a light or heavy vehicle. Regarding these barriers, success in design is obtained when the

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The same barrier can behave satisfactorily when it responds appropriately to such different types of impact.

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 that have different severity indices (transverse kinetic energy of impact), which guarantees a reasonably reduced maximum deformation against impacts of greater severity index and, in all cases, at a severity level (based on the measurement of the deceleration progression to which the vehicle is subjected during the impact) sufficiently low, having , at the same time, the ability to properly redirect the vehicle along its exit path.

The basic configuration of metal safety barriers is that of two basic metal elements joined together and two other elements, a third and a fourth element that are optional:

1º.-The fence (s) or rail (s) are the longitudinal elements arranged horizontally on one or several levels at a certain height continuously, whose function is to contain and guide the vehicle that collides against the same, thus preventing it from passing through the fence or rail element, limiting transverse deformation and guiding it so that it can be reoriented by means of the system in an appropriate manner. The fence can have different configurations: one or several longitudinal profiles that have an open or almost-closed cross-section and in the form of a double or triple wave or in the form of “C” or “sigma”, attached to the post by means of a separating element; tensioned metal cables or rods fixed directly to the pole; longitudinal profiles in the form of double or triple wave whose lower part is attached to metal sheets that can be freely moved and calibrated to oppose a specific resistance when they receive an impact.

2º.-The pole, arranged vertically at regular intervals and fixed to the fence (s) or rail (s), whose function is to support and maintain the fence elements or barrier rail at a preset height during impact vehicle. Posts are generally metal profiles whose section can be in "C", "U", "I", "Sigma" or "Z", round or rectangular closed tubular sections or other types of section, which are buried on an embankment or medium of the road so that a part of its length is inserted into the ground or attached to it by means of a plate anchored to the ground with screws. Before the impact of a vehicle and depending on the energy generated by said impact, the post will deform to a greater or lesser extent by bending and / or twisting with respect to the buried or anchored part.

3º.-The separating element is the intermediate connecting piece that is often placed between a fence or rail and the post. The functions of said separator element are the following:

(I)

attach the fence or railing to the fixing posts at a certain height,

(II)

act as a separating element between said fence or rail and the post to prevent the vehicle wheel from engaging or otherwise engaging the post when hitting the barrier,

(III) keep the height of the fence in contact with the vehicle during the impact, compensating for the dejection effect caused by the post that deforms during the impact, bending back and down, and

(IV) attenuate or absorb some of the impact energy and contribute to the reorientation of the vehicle during the collision. In the latter case, the separator element is called energy absorber. The energy absorption function of the separating element is characteristic of high containment barriers since these barriers have a very robust or rigid basic structure, composed of the fence or robust fences and posts installed at a short distance that are capable of containing heavy vehicles , which makes this structure too rigid to be suitable as an impact containment device for light vehicles. The separator-absorber element is specifically designed to reduce the severity of impacts caused by light vehicles against rigid basic structures, softening the contact against the pole and favoring the reorientation function of vehicles that turn. Occasionally, this element is configured as a single component, such as an assembly of plates and / or metal profiles, configured in a more or less complex manner, or in tubular profiles of square or rectangular section that can be opened or closed. There are also barriers built without the separator or absorber element. In said barriers, the fence element is directly coupled to the post element. In other situations, especially on racing circuit roads, it is possible to find other configurations in which the separator or absorber element is configured by cylinders of resistant elastic material filled with foam or similar materials and placed between the fences and the post or wall external; or even by a triangular metal structure of type

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semi-right acting simultaneously as an absorber element and a pole element, allowing the barrier to move during the impact of the vehicle. Sometimes, the energy absorption capacity of the safety barrier is achieved by means of elastic adapters that are inserted, by way of covers or protections, over the fences or railings.

4º.-A horizontal continuous rear brace that longitudinally connects the barrier posts by the rear of the barrier, joining the consecutive posts by their upper parts or the consecutive separating elements by their rear. The functions of said brace are as follows:

(I)

distribute the stresses caused by the impact between the different posts to reduce the transverse deformation of the barrier and

(II)

compensate and limit the torsional forces between the posts' heads.

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 held by an internally threaded locking nut and one or more washers.

Metal safety barriers designed for different levels of containment and, fundamentally, to contain passenger cars that have different weights and that move at different speeds, often have a rigid spacer or separator element, in order to achieve deformation levels of the Acceptable barriers, in addition to maintaining the stability of the vehicle during and after the collision, limit the severity levels within the lower class (best class) and provide it with an adequate capacity to reorient the vehicle at the exit.

The typical sequence of the impact of a tourism against a metal safety barrier, of those configured by a continuous horizontal fence supported by vertical elements and installed on the margin or median of the road, is as follows:

-The initial impact between tourism and the barrier occurs between the front side (left or right depending on whether the collision has occurred on the left or right side) of tourism and the metal fence. As a result of this contact, the fence transmits the efforts created in this way to the nearest post that begins to deform, twisting and bending backwards. Since the impact occurs in the area in front of the center of gravity of the vehicle, this causes the vehicle to rotate in a direction of reorientation. During the initial contact and, to a lesser extent, successively thereafter, the spacer (if any) keeps the vehicle's wheels away from the base of the post to avoid widening.

-When the post depletes its deformation capacity, when it reaches a certain angle of bending backwards, it is necessary to release the connection that connects this post to the fence to prevent the post from dragging the fence down and prevent the vehicle from destabilizing due to the difference in level that, in such a case, would appear between the height of the contact fence and the center of gravity of the vehicle, causing the vehicle to tip over or cross the barrier transversely with the fence almost folded down. Once the element that joins the post to the fence is released, the fence behaves like a tensile or “cable drag” element transmitting longitudinal and transverse deformation forces to the posts adjacent to the “disengaged” post and propagating, from that mode, the impact on the direction of travel of the vehicle before the turn. The mechanism that releases the junction between fence or fence and post is known as "fusibility."

-Once the first post has been disengaged by the effects of fusibility, the impact spreads as the vehicle is reoriented in the original direction of travel, always in contact with the fence, and successively disengage the posts of the fence placed consecutively, which continues to work as an element subjected to traction, until secondary collision occurs when the rear of the vehicle collides with the fence. Since this secondary impact occurs behind the center of gravity of the vehicle, this causes it to rotate in the opposite direction of the reorientation, stopping the reorientation process and causing the vehicle to leave the system to separate. During said exit, because the vehicle has transversely penetrated a certain distance from the longitudinal alignment of the barrier, the last post of the barrier can also be disengaged in contact with the vehicle. During the secondary impact, the vehicle can also be destabilized and pass through the containment system, if the height of the “disassembled” fence in relation to the vehicle is low enough for this to occur.

The fuse mechanism of the barrier is normally located at the point where the separator and the post meet. This entails "tearing off" the head of one or more screws by passing through the corresponding holes of the post or separator or "progressively" cutting the sheet metal membranes that separate a series of aligned holes that are part of the screwed connections that connect the separator to the pole or pole to auxiliary connecting parts disengaged any intermediate connecting piece, etc.

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In cases where the metal barrier is not provided with a separating element, the only fuse mechanism that has been used, up to the present invention, entails making the post pass through the head of the fence binding screw, an action by which said screw head "is torn" from the elongated hole of the fence that houses said joint. However, this mechanism is very poorly controllable and the charges that cause fusibility vary and are not very repeatable.

During the impact of a tourism-type vehicle, the separator fulfills its functions of separating the fence from the vehicle and maintaining the height of the fence in contact with the colliding vehicle, in addition to contributing to maintaining the deformation of the barrier (transverse width of work) to a minimum. However, the separators have three drawbacks:

(i). Placing a separator between the fence and the post increases the width of the barrier, a fact that creates a serious space problem in situations where the shoulder space, available for the off-road barrier, is reduced, thus creating A traffic safety issue.

(ii). Since the spacer is arranged horizontally between the fence and the post, this produces a dynamic “lever” effect on the head of the post, which distorts the transmission of efforts from the fence to the post due to the loads applied to the barrier when a tourism hits against it at a certain speed.

(iii) .Installing the separator increases the total cost corresponding to materials and installation of the metal safety barrier.

The use of a narrower, more robust and more economical metal barrier on the margins or medians of roads, without a separator, specifically designed for car impacts, requires the use of a special connecting element between fence and post that can provide the system of a highly controlled fuse system (the connection element is released when a preset load value is reached and is released exactly at the necessary moment of the impact sequence). This system allows the barrier to offer the appropriate response to the impact of tourism, thus guaranteeing the following benefits:

a) Prevent the colliding tourism from getting caught in the disengaged posts in its path, since the vehicle travels longitudinally against the barrier by deforming it transversely, and passing over them. To achieve this, it is necessary that the post-deflection bending deformation response of the post is such that, once the vehicle collides with the post, said post has been sufficiently and adequately deformed so that the section of the Pole that is oriented towards tourism is in its position of least inertia and the post, in its entirety, bends considerably by the point where it is buried in the ground.

b) Prevent that, when the post is deformed backwards and downwards to keep the upper part of the barrier in contact with the vehicle, drag the fence vertically and downwards towards the ground, thus guaranteeing tourism stability during the impact and after this one.

c) Ensure that the connecting element connecting the pole and fence is released at the exact moment, neither before nor after, so that the loads and the deformation resulting from the impact are distributed in the largest possible number of consecutive posts, thus limiting the deformation maximum transverse barrier. Premature fusibility increases transverse deformation and can cause entrapment since transverse displacement predominates over rotation displacement and reorientation. If the fuse is late, the fence descends excessively, dragged by the pole, the vehicle is destabilized and can pass over the barrier. In this case, the maximum transverse deformation also increases.

In the patent document GB1141012A a connection between a fence (10) and a post (55) is described by means of a screw (56) that breaks in case of impact of a heavy vehicle, but not in a controlled fuse according to a preset threshold, that is, the union is not decoupled in a controlled manner. The barrier described in GB1141012A is preferably designed to allow a vehicle that travels along the fence to completely tear down the post. Therefore, in order to comply with the regulations of a preset decoupling threshold value, once the barrier of document GB1141012A was installed, the support post would have to be changed resulting in such a complex, long and expensive modification.

WO 2005028757 describes an impact head for a protective barrier that includes cable conduction means adapted to form a spiral connection through which a cable can be threaded. WO 2005/028757 also describes a barrier that requires an intermediate element between the fence and the post: a sliding device that interconnects a plurality of railings and attaches them to the posts. WO 2005/028757 also describes a frangible screw with a rod part, preferably located near the head part of the screw, which can be used to join several components of the safety barrier.

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Description of the invention

The present invention provides a metal safety barrier with a fusible mechanism for bolted joints that connect its horizontal fences, beams or railings to its vertical support posts, which allows said joint element to be released or decoupled in a controlled manner when the transmitted force at the same, as a result of the actions produced in the barrier by the side impact of a vehicle against it, it exceeds a pre-established threshold value, providing the same technical advantages, as regards the state of the art, that the separating element It contributes to the behavior of the safety barrier but avoiding its inconveniences, at the same time, which improves its behavior and also configures a narrower, more robust and more economical metal barrier.

For this purpose and in order to achieve said advantages when compared with the current technique, a metal safety barrier is proposed as defined in claim 1, whose main property is its controlled fuse character, both in time and in magnitude of the force , which provides the following technical advantages:

one). It prevents tourism from being trapped in the disengaged poles, since its passage transversely deforms the barrier, and the vehicle passes over them, since it travels longitudinally with respect to the barrier. To achieve this, it is necessary that the bending-torsion deformation of the post before disengaging is such that, once the vehicle collides with it, the post has been sufficiently and adequately deformed so that the pole section oriented towards tourism is in its position of least inertia, while the pole, in its entirety, bends considerably by the point where it is buried in the ground.

2). It prevents that, when the post is deformed back and down to keep the upper part of the barrier in contact with the vehicle, drag the fence vertically and downward to the ground, thereby ensuring tourism stability during impact and after this one.

3). Ensures that the connecting element connecting the pole and fence is released ("fuse" occurs) at the exact moment, neither before nor after, so that the loads and the deformation resulting from the impact are distributed in the greatest possible number of posts Consecutive, thus limiting the maximum transverse deformation of the barrier.

Premature fusibility increases transverse deformation and can cause entrapment since transverse displacement predominates over rotation displacement and reorientation. If the fuse is late, the fence descends excessively, dragged by the pole, the vehicle is destabilized and can pass over the barrier. In this case, the maximum transverse deformation also increases.

The metallic safety barrier with a screwed fuse connection (3) object of the invention, described below, is constituted by a continuous horizontal impact element formed by one or several horizontal continuous fences or railings (1), supported by means of said fuse link (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 screwed fuse joint (3) is configured (see fig. 4) from a metal screw (5) that has along its threaded rod (10) and at a certain distance from the screw head (9), a straight section (11) or a specific area, preferably cylindrical, that has undergone a specific mechanical, thermal or chemical treatment, so that the mechanical resistance to breakage of said section (11) or screw zone is considerably lower than the rest of the stem sections (10) of the screw. The section (11) or zone of lower mechanical resistance of the rod (10), located below the head (9) of the metal screw (5) that connects the fence (1) to the post (2) of a metal safety barrier , is known as "fuse section" and characterizes the screw (5) as "fuse screw" and the joint (3) between fence (1) and post (2) as a "screwed fuse joint".

This property of the fuse screw (5) that has a "fuse" section (11) characterized by having less mechanical resistance placed along the stem (10) of the screw so that once the joint (3) is assembled between the fence

(1) and post (2), as shown in fig. 9, the fuse section (11) is placed, approximately, in the middle of the junction zone that connects both elements, so that when a tourism collides laterally against the barrier (see fig. 5) the shear forces caused by the collision and which affect the rod (10) of the joint screw (3) connecting fence (1) and post (2) are concentrated, almost completely, in the section or fuse area (11).

In fact, when a tourism collides laterally against the barrier exerting on it a certain lateral force 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 one hand, the post (2) begins to deform back and down while it is buried firmly in the ground (4) and, on the other hand, tourism pushes up the fence (1), causing the upward force (T) that it acts on the fence (1) and another descending force (T) that acts on the post (2). The combination of both forces (T) subjects the rod (10) of the joint screw (3) that connects the fence (1) to the post (2) to a shear type force.

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The concentration of the shear forces, caused by the collision of tourism against the barrier in a specific section (11) of the rod (10) of the bolted joint that connects the fence (1) and the post (2), causes the screw (5) of the joint is broken just by said section (11) because said section (11) has a lower mechanical strength.

Therefore, the behavior of the metal barrier to the impact of a tourism is based on a fusible mechanism that allows to release or disengage the junction (3) between the fence (1) and the post (2), as shown in the Figure 2. Tourism penetrates the barrier laterally at a distance, while the vehicle is redirected and leaves the system. The precise moment, within the temporal sequence of the impact, and the magnitude of the force, caused as a consequence thereof, in which the fusibility or disengagement of the component occurs, will be essential factors in the response of the barrier to impacts and, consequently, in the consequences of that impact. Therefore, to obtain the appropriate response it is necessary that the fuse be very controlled, predictable and repeatable.

One of the technical advantages of the fusibility mechanism, object of the invention, is that the intensity of the mechanical or chemical treatment that is applied to the fuse section or zone (11) of the screw determines the final value of the mechanical resistance to the breakage of said section or zone (11) and, therefore, the value of the difference between it and the nominal mechanical resistance of the screw (5). Therefore, by varying the intensity of said treatment on said section or zone, the instant and the magnitude of the fusibility or disengagement force of the joint (3) can be modulated, as described above.

The treatment applied to said section or zone (11) of the stem (10) of the connecting screw (5) (3) that connects the fence

(1) to the post (2) of the metal safety barrier, to reduce its mechanical resistance and turn it into a fusible zone is, preferably, a mechanical type treatment or mechanization that entails making a cylindrical throat (12) of smaller diameter than that of the stem (10) of the screw and located at a certain distance from the head (9) of the screw, 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 screw stem (10), 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 mechanical resistance value of the screw.

A constructive variation of the mechanical treatment to achieve fusibility (see Figure 7) involves making one, two or more grooves (12 ') in the screw shank (10), at a certain distance from the screw head (9), perpendicular to the shaft 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 amount and depth of the grooves (12 ') and the diameter of the remaining length of the screw shank (10), for a given constituent material, determines the value of the melting force and the mechanical resistance difference between the section or fuse zone and the nominal mechanical resistance value of the screw.

Another constructive variation of the mechanical treatment that is used to achieve fusibility (see Figure 8) is the execution of one, two or more notches (12 '') on the screw shank (10), at a certain distance from the head (9 ) of the screw, with the notch axis perpendicular to the shaft axis (10) or slightly inclined with respect to said perpendicular. Said notches (12 '') may all be located along the same straight section of the screw, as shown in sub-figure 8a, or they may be located in different straight sections close to each other, as shown in sub -figure 8c. In this case, the relationship between the amount and depth of the notches (12 '') and the diameter of the remaining length of the stem (10) of the screw, for a given constituent material, determines the value of the melting force and the difference in mechanical resistance between the fuse section or zone and the nominal mechanical resistance of the screw.

The fuse link (3) that connects the fence (1) to the post (2) is achieved by means of a fuse screw (5) that has a fuse section or zone (11) located on the stem (10) at a certain distance from the head (9) of the log, so that the rod (10) goes through, successively, the fence (1) through the hole (13) made for this purpose and through the post (2) through the hole (14) made to such effect and is located between the fence (1) and the post (2) once the connecting element (3) connecting the fence and post is installed, as shown in figure 9. The joint (3) can incorporate a washer flat (6), preferably rectangular, as shown in figure 13, located in the bolted joint (3) below the head (9) of the screw and above the fence (1) and said flat washer being traversed by the rod (10) of the screw that passes through the central hole (16) of the flat washer (6). Said fused screw connection (3) can also be provided with a second flat washer (7) which also has a central hole (17), preferably round, as shown in Figure 14, located between the post (2) and the nut closing (8).

The technical advantage of using such flat washers (6) and (7) in combination with a fusible screw (5) is that they contribute to strengthening the fence (1) and the post (2) locally around the area of the joint fuse (3) to avoid that, as a result of the impact of vehicles, these elements, fence and post, are deformed locally around the holes (13) and (14), respectively, that are part of the joint (3) provided with fuse screw

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(5). The local deformation of the fence (1) or the post (2) around the holes (13) and (14), would consume an uncontrollable part of the stresses transmitted to the fusible joint (3), thereby damaging to the phenomenon of concentration of the deformation forces that influence the section or fusible zone (11) of the screw, as well as the extremely sharp nature of said forces. All these interferences (dispersion of the transmitted forces and loss of the shear character of the forces) would disturb the control that can be exerted on the level of force and on the instant of fusibility of the 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 in a metal safety barrier configured solely by a continuous horizontal fence (1) and vertical support posts (2) arranged at regular intervals, such as the one shown in Figure 3. Notwithstanding the foregoing, the fuse type connection (3) also offers the same technical advantages when the barrier of metal safety constituted by the fence (1) and posts (2) also incorporates a rear tie rod (25) connected to the post (2) by means of a screwed connection (26), preferably, a non-fusible joint, as shown in the figure 11.

The same technical advantages can be obtained when the type of fused screw connection (3), object of the present invention, is applied to a metal safety barrier having two fences (1) arranged symmetrically on each side of the post (2), as shown in figure 12.

Finally, if the security fence to be designed needs a level of containment slightly higher than that required to contain tourism-type vehicles, such as that required to contain light trucks or coaches, whose center of gravity is located at a height greater than that of cars, it may be necessary to install an intermediate piece (15) between the fence (1) and the post (2), as shown in Figure 10, which does not correspond to the invention. Said intermediate piece (15) would have an insufficient size to be considered a true separating element, since its only function would be to allow a slight vertical displacement of the fence (1) with respect to the post (2), to a degree sufficient to compensate for the imbalance between the different heights of the centers of gravity of the vehicle and of the barrier so as to maintain the stability of the vehicle and prevent the vehicle from passing over the barrier. In this case, both the bolted joints (3 ') between the fence (1) and the intermediate piece (15), and the bolted joints (3' ') between the piece (15) and the post, alternatively, or both joints (3 ') and (3' '), at the same time, can be fuse type joints. This would allow some upward displacement of the fence before the fuse junctions (3 ’) or (3’ ’) are disengaged.

Another constructive alternative, to achieve the controlled fusibility of the joint (3) located between fence (1) and post (2), is to use a fuse washer (18) instead of a screw (5) whose stem (10) has a section or fuse zone (11), as shown in Figure 15, which does not correspond to the invention. The fuse washer (18) is installed below the screw head (5) and above the fence (1) and allows the screw head (5) to pass through its central hole (19), after apply a certain force on the joint as a result of the collision of a vehicle against the barrier.

Figure 15 shows how the “non-fusible” rod (20) 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) through its central hole (17) and the lock nut (8).

Description of the drawings

To complement the description and to better understand the characteristics of the invention, by using a preferred embodiment of the practical application, a set of drawings is attached below. These drawings are an integral part of said description and will be understood to be illustrative and not limiting.

Figure 1.- Shows the straight cross section of a metal safety barrier comprising a continuous horizontal fence (1) supported, by means of the screwed fuse joint (3), by 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 what happens when a tourism collides laterally against a metal safety barrier that shows the behavior of the fusible joint

(3) located between the fence (1) and the post (2).

Figure 3.- It is a perspective side view of a section of a metal safety barrier comprising a continuous horizontal fence (1) connected by means of screwed fuse connections (3) to the corresponding vertical posts (2) that are inserted in the ground (4), said unions comprising a fusible screw (5), a rectangular flat washer (6) located below the screw head and a square flat washer (7) located below the locking and tightening nut ( 8).

Figure 4.-Corresponds to a view in longitudinal longitudinal section of a fusible metal screw (5), which represents the head (9) of the screw, the stem (10) and the fusible section (11).

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Figure 5.-It is 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 the tourism that collides laterally against the barrier and the forces (T) subsequently caused to affect the fence (1) upwards and the post (2) downwards, subjecting shear stresses to the fuse section (11) of the rod (10) of the screw of the screwed joint (3) that connects the fence ( 1) and post (2).

Figure 6.- It shows two images, sub-figure 6a and sub-figure 6b, of a fusible metal screw (5) having a fusible section materialized by a cylindrical throat (12) placed in a certain section of the stem (10) by under the head (9) of the screw. Sub-figure 6a shows the meridian section of the fuse screw (5) and subfigure 6b shows 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) having a fusible section materialized by a pair of slots (12 ') made in a section stem determined

(10)

and perpendicular to it below the head (9) of the log. Sub-figure 7a corresponds to the meridian section of the fusible screw (5) with the two slots (12 ') made in the same section, sub-figure 7b is a three-dimensional view thereof and sub-figure 7c shows the section Fuse screw meridian (5) with both grooves (12 ') located in two different sections, but close to each other, of the stem (10).

Figure 8.- Shows three images, sub-figure 8a, sub-figure 8b and sub-figure 8c, of a fusible metal screw (5) having a fusible section materialized by a pair of notches (12 '') made in a certain section of the stem

(10)

and perpendicular thereto below the head (9) of the screw. Sub-figure 8a shows the meridian section of the fusible screw (5) with both notches (12 '') made in the same section, sub-figure 8b is a three-dimensional view thereof and sub-figure 8c shows the meridian section of the fusible screw (5) with the two notches (12 '') located in two different sections, close together, of the rod (10).

Figure 9.-Shows two images. Sub-figure 9a shows an exploded view and sub-figure 9b shows an assembled view of the fused screw connection between a fence (1) and a post (2) of a metal safety barrier composed of a fuse screw ( 5), characterized by having a fuse section (11) that passes successively through the central hole (16) of a flat washer (6) placed 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) placed below the locking and tightening nut (8) of the joint.

Figure 10.- Shows the straight cross section of a metal safety barrier, which does not correspond to the invention, composed of a continuous horizontal fence (1) supported, by means of an intermediate piece (15), on a vertical post (2 ) inserted in the ground (4) and in which the joint (3 ') located between the fence and the intermediate piece and / or the joint (3' ') located between the intermediate piece and the post is a fusible type joint .

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

Figure 12.- Shows the straight cross section of a double metal safety barrier composed of two continuous horizontal fences (1) and a vertical post (2), said fences being arranged symmetrically on each side of the post and both fences supported by said post to which they are coupled by means of screwed fuse connections (3), while the vertical post (2) is inserted into the ground (4).

Figure 13.- Shows the three-dimensional image of a rectangular flat washer (6), placed below the head of the fusible screw, which has an elongated central hole (16).

Figure 14.- Shows the three-dimensional image of a square flat washer (7), placed below the head of the fusible screw, which has a round central hole (17).

Figure 15.-Shows two images. Sub-figure 15a represents the exploded view and sub-figure 15b represents the assembled view of the screwed fuse joint located between a fence (1) and a post (2) of a metal safety barrier, which does not correspond to the invention, composed of the combination of a non-fusible screw (5) and a fuse washer (18) that passes successively through the screw shank (20), the central hole

(19) of the fuse washer (18) placed 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) placed below the lock and tightening nut (8) of the joint.

Example of an embodiment of the invention

Figures 1, 3, 6, 9, 11, 12, 13 and 14 show a specific embodiment of the present invention comprising a metal bolted joint (3) between the fence (1) and the post (2) of a metal safety barrier, comprising a metal screw (5) that preferably has a round head, a flat washer

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metal (6), preferably rectangular, located below the head (9) of the screw, another flat metal washer (7), preferably square, located under the nut, and a metal lock nut (8), whose screw

(5) has a section or zone (12), preferably cylindrical, at a certain distance from the head (9) of the screw, whose diameter is smaller than the diameter of the rod (10) and is in throat shape Said zone is called the section or fuse zone, since it is the zone of the rod (10) and the screw (5) that has the minimum mechanical resistance. Therefore, the designation also covers the screw known as the fusible screw.

The stem of the fusible screw (5) goes through, successively, the flat washer (6) placed under the head (9) of the screw, the fence (1), the post (2), the flat washer (7) and the nut (8) which is the component that closes and tightens the bolted joint (3), as shown in Figure 3. More 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 hole (14) of the post (2), the central hole (17) of the square flat washer (7) and the central hole of the locking nut and tighten (8), as shown in figure 9.

The position of the fuse section or zone (12) along the stem (10) of the fuse screw (5) is such that once the joint (3) between the fence (1) and the post (2) has been definitively executed ), as shown in Figure 9, the section

or fuse zone (12) machined in the rod (10) as a throat-like notch, is limited, approximately, to the area inside the holes (13) of the fence (1) and (14) of the post ( 2) and, therefore, it can be considered that the theoretical surface that separates the fence (1) and the post (2) would “cut” the rod (10) of the screw (5) that connects both in the fusible 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 comprising only 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 has, in addition to the components mentioned above, one or two subsequent horizontal continuous braces (25) fixed to the back of the posts (2), as shown in figure 11,

or to double metal barriers, that is, barriers composed of two fences (1) arranged symmetrically on each side of the posts (2), as shown in Figure 12.

References cited in the description

This list of references cited by the applicant is only for the convenience of the reader. It is not part of the European patent document. Although great attention has been paid when collecting references, errors or omissions cannot be excluded and the EPO denies any responsibility in this regard.

Patent documents cited in the description

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 GB 1141012 A [0017] • WO 2005028757 A [0018]

•

 WO 2005028757 A [0018]

Claims (5)

1. Metal safety barrier for use on the margins and medians of roads to contain 5 vehicles comprising at least one horizontal fence (1) and a series of vertical posts (2), said fence (1) having a series of holes (13), each of said posts (2) having a hole (14) said barrier being of the type that contains side impacts of vehicles with a controlled decoupling of fence (1) and post (2) according to a predetermined decoupling threshold value, characterized in that said barrier comprises a bolted connection mechanism of fence (1) and post (2), comprising said 10 connection mechanism screwed a fuse screw (5), said screw (5) having a rod (10), said rod (10) having a zone (11) of lower mechanical resistance (11, 12, 12 ', 12 ") that the rest of the rod (10), said area of lower mechanical resistance being located at a certain distance from the head (9) of the screw and in a position such that, once the screw connection (3) is executed, said section has lower mechanical resistance (11, 12, 12 ’, 12”) is placed, at the same time, both inside the hole (13) of the fence (1) and the hole (14) of the post (2). 2. Safety barrier according to claim 1, characterized in that said zone (11) of lower mechanical resistance (11, 12, 12 ’, 12”) of the rod (10) has been obtained by applying a heat treatment. 3. Safety barrier according to claim 1, characterized in that said zone (11) of lower mechanical resistance (11, 12, 12 ’, 12”) of the rod (10) has been obtained by applying a chemical treatment. 4. Safety barrier, according to claim 1, characterized in that said zone (11) of lower mechanical resistance (11, 12, 12 ’, 12”) of the rod (10) consists of a throat-like section. 25 5. Safety barrier according to claim 1, characterized in that said zone (11) of lower mechanical resistance (11, 12, 12 ', 12 ") of the rod (10) consists of at least one groove (12', 12 ' ') which is inclined with respect to the perpendicular axis of the rod (10). Security barrier according to any of the preceding claims, characterized in that the barrier further comprises an additional horizontal fence that is installed, symmetrically to the first horizontal fence, on the other side of the posts (2). 7. Safety barrier according to any of claims 1 to 5, characterized in that the barrier 35 further comprises at least one continuous rear tie rod (25) connected to each post (2) by means of a joint (26). 40 eleven