A DEVICE FOR CALIBRATING THE DECELERATIONS OF "LIGHT" VEHICLES UPON IMPACT

Abstract: A device (9) used in steel-made road safety barriers comprising a band or strip (2) and posts (1), wherein the device may be mounted on a lateral barrier or on a traffic divider. The device (9) is located in an intermediate position between the base of the posts and the upper spacer, which is designed to absorb the impact due to heavy goods vehicles, and the device connects a longitudinal rail (2) to the posts themselves (1). The device forms a spacer (9) specifically designed for light vehicles, and moves rearward under the impact force by sliding transversally; the device calibrates and gradually absorbs the impact force and therefore the decelerations transmitted to the vehicle and to its passengers.

Description: Descr i pt i on A device for calibrating the decelerations of "light" vehicles upon impact Techn i ca I Field The present invention relates to a device to be mounted on the posts of a road barrier, to act as a spacer for the lower longitudinal rail, in order to calibrate the decelerations which are transmitted to "light" vehicles during i mpact . The device is mainly designed to be applied to metallic road safety barriers including a band or strip, and posts, and is intended for use on lateral barriers or traffic dividers, and in particular as a spacer and/or lower energy absorbing device for automobiles. However, even if the device has been realized in order to solve the particular problems associated with this type of barriers, its operation during impact and its construction makes possible its more generalized use; i n particular, it could also form the upper spacer, in order to resist to impacts by heavy vehicles or it could be employed in steel-made New Jersey barriers for connecting the front part to the inner uprights. Background Art As known in the field of safety barriers and in particular those to be installed on traffic dividers of motorways, very high retention levels -of the order of 600 kJ- are required in order to prevent vaulting by a goods vehicle of more than 40 tons and with a high center of gravity. Barriers with high resistance are consequently very rigid, and for this reason, with respect to an impact caused by a light vehicle (automobiles with a weight of between 800 and 1500 kg), even at very high speeds and energies up to 70 KJ , no problems of vehicle retention arise, but the decelerations transmitted in this case to the passengers may be very high and fatal. In many cases of accidents involving automobiles, the relatively low energies involved are not sufficient to "trigger" the barrier displacement so as to reduce and calibrate the decelerations. On the other hand, it is anyway obvious that in the field of safety barriers for roads and especially in the field of traffic dividers, the most important problem is that of obtaining protection and preventing vaulting for the whole variety of vehicles circulating on the road, which have masses, sizes and velocities which are extremely different. Barriers suited to retain heavy goods vehicles, with a weight between 3 and 44 tons, may represent a fatal obstacle (due to their rigidity) in case of impacts by vehicles with a weight between 800 and 1500 kg. In particular, in the field of metallic barriers including a band or strip and posts, that is in the case of guardrails, said high absorption energies are obtained by means of a blade having a triple wave configuration, and upper spacers which are more and more wide, heavy, and not easily deformable, connected to each other through diagonally arranged tubes, and said posts are becoming more and more high and close to each other . The current metallic barriers comprise a lower rail - the so-called "wheelguard" - in an intermediate position between the upper spacer and the base of the posts, which prevents a "highly localized" impact by an automobile against a post, that is the immediate stop of the vehicle and the consequent extremely high peak of the decelerations, not bearable by the passengers. The main problem of current high resistance barriers is due to the fact, that the upper spacers have a noticeable transversal dimension (with respect to the row formed by the posts), so that, in practice, the automobile hits the barrier on the triple wave and on the upper spacer at the level of the windshield (see Fig. 1), but said components are designed to resist to impacts by heavy vehicles, so that the automobiles will be seriously damaged and the passengers wi ll be seriously injured; in practice, the automobile does not hit the lower rail or "wheelguard", and in any event the latter is not at present connected to the posts by means of deformable spacers in such a way as to reduce and calibrate the decelerations transmitted to the passengers . Disclosure of invention An object of the present invention is to realize a device which connects the lower rail or "wheelguard" to the posts, and which has a transversal dimension comparable to that of the upper spacer, in such a way as to be able to protect the automobile from a direct impact against the upper spacer, w ich is very rigid because it is designed and constructed so as to absorb the impact produced by goods vehicles. Another object of the present invention is to calibrate the decelerations of the automobi le (light vehicle) which hits the device, by providing a "sliding" system in the device of the invention, so that the device can absorb part of the energy while moving rearwards. This further object of the present invention therefore amounts to transforming the current barriers of the guardrail type into "bivalent" barriers, that is, to adapting them to absorb not only impacts produced by heavy goods vehicles, but also those caused by automobiles, without giving rise to unacceptable decelerations acting on the passengers. The invention solves the above problems by providing in an intermediate position, between the base of the posts and the upper spacers, a spacer which is deformable in a self-adjusting way, and which is associated to the traditional longitudinal rail or "wheelguard"; said spacer comprises one or more elements which can slide in a transversal direction, and is connected to the posts. The spacer, the elements by which it is formed, and the means used for the transversal sliding, may be real ized in many different ways. Moreover, adjustment means may be provided, for adjusting the resistance of the device against an impact caused by a vehicle and in the first place against an impact caused by a light vehicle. The device may be mounted on a barrier to be installed on the side of the road or on a traffic divider. The device could also be employed - after obvious dimensional changes -, as an upper spacer connected to the triple wave, or be used in steel-made New Jersey barriers, in order to connect the front part of the barrier to the inner uprights. Brief Description of Drawings Th e present invention will now be explained in more detail by means of preferred embodiments and variants of these embodi ents, which are given only for illustrative and non- I i m i tat i ve purposes, and are shown in the annexed drawings, wherein: Fig. 1 is a schematic view of a traditional metallic barrier comprising a triple wave, wherefrom it is possible to obtain the relative sizes of the automobile as compared to the barrier components, and thereby understand the objects of the present invention; Fig. 2a is a side view of the device of the present invention, in its simplest real ization, before an impact ( initial cond i t i on ) ; Fig. 2b is a side view of the device of Fig. 2a, after the impact (final position); Fig. 3a is a side view of a second possible embodiment of the device of the invention, formed by two elements, fixed to the post and in the initial condition; Fig. 3b is a side view of the device of Fig. 3a in the final position after the impact; Fig. 4 is a side view of the device of Fig. 3a, according to a variant comprising a box-l ike rai l ; Fig. 5 is a view simi lar to that of Fig. 4, in the initial device position, wherein the rai l is a double blade; Fig. 6 is a side iew of a device according to a third possible embodiment, comprising adjustment means for the sl iding movement during the impact, and therefore also of the decelerations involved, the adjustment means being provided by holes; Fig. 7 is a side view of a fourth embodiment of the device according to the present invention, which is mounted on a metallic traffic divider; Fig. 8a is a top view of the device of Figs. 3a, 3b; Fig. 8b is a rear side view of the device of Figs. 3a, 3b; Fig. 9a is a cross-sectional view and a front iew respectively, of the first (stationary) element of the device of Figs. 3a and 3b; Fig. 9b is a cross-sectional view and a front view, respectively, of the second (movable) element of the device of Figs. 3a and 3b; Fig. 9c is a front sectional view showing the insertion of the second movable element of the device inside the first stationary element of the same device, and their mutual connection; Fig. 10a is cross-sectional view and a front view respectively, of the first (stationary) element of the device according to a different embodiment; Fig. 10b is a cross sectional view and a front view respectively, of the second (movable) element of the device according to the embodiment of Fig. 10a; Fig. 10c is a front sectional view showing the insertion of the second movable element of the device, inside the first stattonary element of the device, and their mutual connection, according to the embodiment of Figs. 10a and 10b. Best Mode of carrying out the Invention Fig. 1 shows a traditional metallic traffic divider comprising a triple wave, Including several posts 1, a wheelguard or lower rail 2 which is usually formed by a steel channel section, and an upper spacer 3' to which the band with a triple wave shape 3 is attached. It can be noted that the transversal dimension and the height with respect to the ground, of the spacer 3', w ich is constructed so as to resist to impacts caused by heavy vehicles, are such that the automobile hits in fact directly against the spacer at the level of the windshield whereas the "wheelguard" is not involved; for this reason, serious consequenses are to be expected. On the other hand, according to the present development in the field, the barrier comprises posts which are very closely arranged, and spacers having a remarkable transversal size, a high weight and a high rigidity, connected to each other by diagonal tubes (not shown), with the aim to retain goods vehicles. The following figures show how the problem is solved by the i nvent i on . In its simplest embodiment illustrated in Figs. 2a and 2b, the deformable cushioning element is formed by a single movable element 4. The device of the invention, which is fixed in a position between the base of the post 1 and the upper spacer (the latter being omitted in the figures following Fig. 1), is substantially formed by this movable element 4, realized in the shape of a steel channel section, similar to the channel section (4') shown in Fig. 9a in cross-section, but comprising two slots 8 for the sliding movement instead of one. The two clamping bolts 5, are used to "fix" the movable element 4 to the post 1, in a way similar to that shown in Figs. 8a-8b (even if in the latter case the element 4' is stationary); said clamping bolts are introduced in the two slots 8 of Fig. 2a, which are obtained on the greater side of the movable element 4. The bolts 5 are also dri en in the post 1, specifically inside two holes of the respective post (see Fig. 8 showing how the connection is carried out in principle, even if this Fig. refers to the embodiment of Figs. 3a and 3b) . If the device according to the invention, in the simplified embodiment of Fig. 2, was observed from above (top view) like in Fig. 8, in this figure the element 9 and the bolt 10 would have to be omitted, and this figure would comprise a movable element 4' which would be longer than the movable element 4 (which is typical of the other embodi ents), for its connection with the longitudinal rai l by means of the round-headed fixing bo l t 7 . At its left end in Fig. 2a, the movable steel channel section 4 forms a front wal l 6 si ilar to the front wall 6 of the movable element 9 of Fig. 9b, corresponding to the second embodiment (Figs. 3a, 3b). The lower rail 2 is fixed to the plurality of front walls 6 of the different movable elements 4 corresponding to the devices of the present invention, associated to the respecti e posts 1 of the barrier; said lower rail may form a continues steel channel section, or a box-like configuration 11, or a double wave 12 (see Figs. 4 and 5) or other configurations not shown in the drawings. In the case of a lower rail having a box-like configuration 11 (Fig. ), the fixing operation to the the movable element 4 requires a longer bolt, e. g. the bo 11 7 " " shown in Fig. . As shown in Fig. 2b, the movable element 4 moves to the right upon impact, and the clamping bolts 5 will thereafter possibly be located at the opposite end of the slots 8, at the end of stroke position. The lower (continuos) rail 2 will have the function to stop the motion of the colliding vehicle (in the first place an automobile), while the displacement shown in Fig. 2b will allow to "cushion" the impact force , thereby limiting and cali rating the decelerations. T is is the reason for using the definition "a device for calibrating the decelerations". Figs. 3a and 3b show a second embodiment of the dβvloβ, in which a movable element 9 having a shape shown In Fig. 9b, is partial ly inserted inside the stationary element 4' (shown in Fig. 9a) fixed to the post 1, by means of the bolts 25. In this case, as shown in Fig. 8a, the bolts 25 are introduced into circular holes 15 of the stationary element 4' and through holes al igned with the holes 15, which are provided on the post 1. The movable element 9 slides upon impact by a vehicle, inside the stationary element 4' , w i le the greater sides of these two elements remain in contact. The bolt 10 is used for the purpose of mutual ly "fixing" the two elements 4' and 9 of the device, but it sl ides in the slot 8 during the impact (observe that in this embodiment a single slot is sufficient). This second embodiment is preferable; It prevents bending of the movable element 9, since the latter is constrained to sl ide inside the stationary element 4'. Fig. 3b i l lustrates the displacement of the movable element 9 inside the stationary element 4' upon an impact by a vehicle. The embodiment according to Fig. 6 differs from that according to Figs. 3a and 3b, in that a plural ity of holes with "programmed" breakage 13 is provided instead of the slot 8. Alte nati ely, the bolt 10 could be arranged inside a slot 8 located ahead (upstream) of the plural ity of holes 13. Said holes 13 are useful for gradual ly decelerating the vehicle, due to the fact that the bolt 10 must successively break the thin walls of material located between adjacent holes 13. If a slot 8 is also provided, during the first displacement inside the slot 8 the device wi l l oppose a reduced resistance, but afterwards the bolt 10 wi l l have to "extrude" part of the sheet in the vicinity of the holes 13. The choice of the thickness of the wal l between two respective holes (corresponding to some mm), is also a way to adjust energy absorption and therefore is a means to cal ibrate decelerations. According to the embodiment of Fig. 6, once the movement of the movable element 9 has been "triggered", the slot 8 alone wi l l first oppose a minimal resistance, and thereafter a condition is reached in which the resistance can be gradual ly increased in order to resist more and more to the motion of the vehicle advancing during the impact against the device. Therefore, a constant mutual distance between the various holes 13 wi l l lead to a gradually Increasing resistance opposed by the different layers of interposed sheet steel, to the momentum associated to the collision. This embodiment corresponds best to the principle on which the present invention is based: that is, the principle of decelerating the vehicle in a gradual manner. In the preferred embodiment this gradualness is firstly obtained by progressi ely reducing the impact force during the first period of the impact, - and this can be attained by means of the sl iding movement of the movable element inside the stationary element-, and secondly by the increasing resistance opposed by the plurality of holes "extruded" by the bolt. In case of col l isions involving even higher energies, during a second period the col l iding vehicle wi l l be decelerated because of the deformations of the spacer and of the post. The device must be cal ibrated with regard to impacts caused by automobi les, and it Is obvious, therefore, that the device itself and the "wheelguard" wi l l undergo considerable deformations and wi l l break at certain spots, in case of impacts due to heavy goods veh I c I es . Fig. 7 shows a further embodiment of the device according to the present invention, which is specifical ly designed for traffic dividers. Even if al l previous embodiments relate to lateral barriers to be instal led on the side of the road, that is to barriers protecting only one side, it can be understood that the device according to the invention -due to its versati l ity- lends itself to the use in a traffic divider too, which protects two sides at the same time. From the point of view of its construction, only a symmetrical reproduction of the structural components wil l be necessary, with the only exception that a single central supporting post 1 and a single stationary symmetric double element 14 wi l l be needed. T is appl ies also to the device shown in Figs. 2a and 2b, comprising a single element, in which, by providing slots with a greater length and inserting the bolts at the middle of the slots, the safety device is suited to slide also on the opposite side with respect to the side were the impact has occured. For this application involving traffic dividers for the protection on two sides at the same tune, the same principle applies with regard to the operation of the device, as has been extensively described previously, both with respect to the form of the rail and to the means used to finely calibrate the deceleration of the co I I i d i ng veh i c I e. In the same way, Figs. 10a, 10b, 10c show further embodiments of the movable element 9"' and of the stationary element 4"'; they illustrate the box-like sections of the respective two elements, when separated from each other, and the cross-section of the two elements, when one of them is introduced inside the other one. As has been previously done for the Figs. 9a, 9b, 9c, numeral 16''' now indicates the hole obtained on the movable element 9, for the introduction of the clamping bolt 10"' slidable inside the slot , w ile numeral 17"' denotes the hole on the bent wall or fin 6"', the latter hole being obtained on the movable element 9"' for the insertion of the clamping bolt 7"' rigidly connecting the movable element to the lower rail. According to Fig. 10, the structural difference with respect to Fig. 9 obviously consists in providing a bolt 10"' which is sufficiently long to reach the opposite end of the element 4"', for the mutual connection of the two elements of the device. The de ice according to the present invention, located in an intermediate position between the base of the posts and the spacer, allows to cal ibrate the decelerations of the colliding vehicle, both for high and low masses. It radically extends the limited operation of the traditional "wheelguard" and it is also suited to be realized according to further interesting embodiments, due to its structural versatility, said further embodiments comprising instead of the steel channel sections connected by bolts and instead of the other realizations generally disclosed in the description, other functional elements with different cross-section, e.g. box-like elements, elements shaped like a parallelepiped, or otherwise shaped, which are steel-made or made of fiber glass, etc.

Claims: C LA I MS 1. A device used in steel- ade road safety barriers comprising a band or strip and posts, characterized in that the device connects the lower rail or "wheelguard" to said posts and has a transversal size comparable with that of an upper spacer, in such a way as to protect an automobile from a collision against the upper spacer, the latter being very rigid and designed to resist to impacts of goods vehicles; said device being further characterized in that it cal ibrates the decelerations of an automobile or a light vehicle hitting the device itself, and comprises a sliding system in the device of the invention, so that the latter, while moving rearwards, can dissipate and absorb part of the impact energy. 2. A device used in steel-made road safety barriers comprising a band or strip and posts, according to claim 1, characterized in that it comprises a movable element (4) formed by a structural steel comprising slots (8) obtained on the greater side or wall of the movable element itself, the latter being connected to a post (1) by means of clamping bolts (5) introduced in said slots (8) and driven in the post (1); wherein the said movable element (4) includes a front wall (6) attached to a lower rail (2), and wherein the movable element (4) translates upon impact by a vehicle, towards the post, and the clamping bolts (5) possibly reaching their end- of-stroke position, at the opposite end of the slots (8). 3. A device used in steel-made road safety barriers comprising a band or strip and posts, according to claim 1, characterized in that it comprises a movable element (9) which is partial ly inserted in a stationary element (4') rigidly connected to the post (1 ) by bolts (25), wherein the said bolts (25) a r e introduced in circular holes (15) of the stationary element (4') and in corresponding holes provided on the post (1) and al igned with the circular holes (15); said movable element (9) being sl idable upon impact by a vehicle, inside said stationary element (4'), even if, due to the presence of a clamping bolt (10) for the mutual connection of the two elements, the greater sides or wal ls of said elements (4', 9) remain in contact with each other during the col l ision; and wherein, possible obl ique displacements of the movable element (9) a r e prevented due to the fact that the latter is constrained to sl ide inside the stationary element (4') and the sl iding movement of at least one bol (10) is guided along a corresponding slot (8). 4. A device used in steel-made road safety barriers comprising a band or strip and posts, according to claim 1, 2 and 3, characterized in that the rai l is formed by a continuos channel. 5. A device used in steel-made road safety barriers comprising a band or strip and posts, according to claims 1, 2 and 3, characterized in that the rail is formed by a continuos sheet with a configuration of a double wave. 6. A device used in steel-made road safety barriers comprising a band o r strip and posts, according to claims 1, 2, 3 and 4, characterized in that the rail is formed by a box-like structural steel, and the movable element (9) is attached thereto by means of a bolt whose length is greater than the cross-section of said struct ura I steel. 7. A device used in steel-made road safety barriers comprising a band or strip and posts, according to any of the preceding claims, charac erized in that said stationary element (4') is laterally provided in its longitudinal direction, with a plural ity of holes (13) designed to be sequentially broken, wherein a clamping bolt (10) is inserted in the first of them, and the gradual deceleration of the colliding vehicle is obtained by means of the successive extrusion performed by the clamping bolt (10), of the walls formed by the material located between neighbouring holes (13). 8. A device used in steel-made road safety barriers comprising a band or strip and posts, according to the preceding claims, characterized in that said stationary element (4') is lateral ly provided in its longitudinal direction, with a slot (8) and with a plurality of holes (13) designed to be sequentially broken, wherein the said clamping bolt (10) is introduced in said slot which is located upstream of said plurality of holes (13). 9. A device used in steel-made road safety barriers comprising a band or strip and posts, according to the preceding claims, characterized in that it is mounted on a lateral barrier for protection of only one side. 10. A device used in steel-made road safety barriers comprising a band or strip and posts, according to the preceding claims, characterized in that it is mounted on a traffic divider for protection of both sides of the barr i er .

Inventors: BRUSCHI STEFANO, CAMOMILLA GABRIELE, BRUSCHI, STEFANO, CAMOMILLA, GABRIELE
Applicants: AUTOSTRADE CONCESS CONST, BRUSCHI STEFANO, CAMOMILLA GABRIELE, AUTOSTRADE CONCESSIONI E COSTRUZIONI, BRUSCHI, STEFANO, CAMOMILLA, GABRIELE
Application year: 1999
Main classification: E01F15
IPC codes: E01F15