DE202008018355U1 - Impact absorbers on traffic routes - Google Patents

Abstract

Impact absorbers in front of obstacles next to traffic routes with a predetermined energy reduction capacity, having a head area (9), an end area (10) and an intermediate area (11) therebetween, characterized in that the energy removal capacity in the end area (10) of the impact attenuator is lower than in the central area ( 11).

Description

The invention relates to an impact absorber in addition to traffic routes with a predetermined energy dissipation capacity, with a head area, an end area and an intermediate area therebetween. The impact absorber is constructed as a protection device against obstacles in order to dampen an impact of an approaching vehicle and thus to keep damage away from the occupants of the vehicle. He also serves the protection of the object.

State of the art

It is a generic impact absorber with the name Vecu-Stop ^® the company SPS known ( 1 and 2 ). In this crash cushion ( 1 ) are two rows of damping elements ( 20 ) arranged with an identical energy dissipation capacity one behind the other, wherein the cylindrical damping elements are aligned with their axis of symmetry perpendicular to the ground. They are essentially rigid over subsurface support elements ( 4 ), which hold the elements at a certain height, interconnected. The crash cushion has an end support at its end ( 14 ) on.

Furthermore, a system is known, which consists of several in series one behind the other elastic cylinders ( 21 ) consists. This arrangement includes substantially similar cylinders, with one of the cylinders ( 22 ) in the center of the arrangement has a lower energy dissipation capacity compared to the other cylinders. Thus, there is a tendency for the energy dissipation capacity to increase or to remain constant in terms of energy dissipation capacity with a weaker link.

The described arrangement of impact absorbers have the common feature that they are largely composed of the same elements. Further, their arrangement is such that either an increase in rigidity tends to take place in the direction of the assemblies, which always involves an increase in the energy dissipation capacity of a damper or the energy dissipation capacity remains constant.

In crash tests with the described systems, one finds a high average of negative acceleration values, the so-called ASI value, especially in the last part of the crash cushion. The ASI (Accelerating Severity Index) is a conventional index that provides insight into the impact severity and possible injury to vehicle passengers due to an impact. This value is obtained from the quadratic average of the delay for three directions (forward, sideways, up) and compared to guideline values that are considered safe.

The starting point for the invention were evaluations of crash tests, which showed that the highest values can be recognized in the last time segment of an ASI value representation. From this, for the first time, the knowledge was derived that at the end of the damping process, the energy absorption property of the then affected area is too pronounced in relation to the energy still present in a vehicle at that time. Due to the fact that the impact absorber according to the invention is "softer" towards the end, the circumstance of the lower kinetic energy in the vehicle at the end of the damping travel or the impact duration is taken into account. In this way, a significant reduction of the ASI value is possible, whereby the risk of injury to the occupants of a motor vehicle is reduced and thus a higher probability of survival is ensured.

task

The object of the present invention is to improve an impact absorber of the type mentioned in such a way that peak ASI values can be avoided, in particular at the end of the impact.

solution

The object is achieved in a generic crash cushion in that the energy dissipation capacity in the end of the crash cushion is lower than in the central region.

Essence of the invention

At a special, in the 3 - 6 illustrated embodiment of a crash cushion is an assembly which has at least three sub-areas, namely at least one head area after the impact head, at least one central area and at least one end portion.

These at least three parts differ not only because of their local layout but also because of their characteristics.

According to the invention, the energy dissipation capacity of the end region is below that of the central region, so that no ASI peaks occur towards the end of the impact process.

Advantageously, the head area and the middle area have an energy reduction capacity, which rises from the head area behind the impact head towards the end of the middle area.

Thus, as a unit, the impact absorber has an energy dissipation capacity of increasing type from the impact head toward the center area. Following this, the energy reduction capacity in the end region decreases again or is lower compared to the middle range.

The individual areas have cells (damping elements), which are arranged one behind the other, deformable and thereby energy-converting and can be arbitrarily arranged in space with respect to their orientation is essential that the energy dissipation capacity in the end region is lower compared to the central region.

The cells may have various external shapes, symmetric or asymmetrical, such as. B. cuboid, polyhedral or cylindrical.

In this case, depending on the selected shape, a cell, for. B. a symmetrical shape such. B. a cylindrical whose axis of symmetry have a vertical or horizontal orientation. The horizontal orientation may be such that the symmetry axis is parallel or vertical to the impact direction.

The interior of the successive cells can have reinforcing internal structure elements, whereby the energy reduction capacity can be determined constructively in whole or in part. Furthermore, it is possible to influence the energy reduction capacity by the wall thickness of the individual cells or by a certain shape.

This form could z. B. be an elliptical, which is arranged so that sets a low energy reduction capacity. This is achieved by z. B. the impact direction is perpendicular to the connecting line of the foci. If you turn 90 ° you will get the opposite effect, here is a higher energy reduction capacity.

Within the subregions is also a combination of reinforcing internal structure elements and a special shape possible, as well as other combinations of form, reinforcements and form arrangements.

A portion of the crash cushion usually has multiple cells. These may be connected to each other by means of fasteners or may be in an enveloping shape, close to tight, loose or even with fastening means, stand together.

The individual different cells with their different energy dissipation capacities can be connected to one another from the impact head to the end region with fastening means to form a coherent unit. It is also possible to surround all areas with an enclosing guard rail arrangement, so as to ensure a cohesion.

In a crash cushion, the set height of the cells is usually less than the average clear height of the ground clearance of a car. This configuration ensures the optimum height for an impacting car. The set height is ensured by means of so-called. Zwischenbaustützen, which have on their ground facing the stand elements. These stand elements, which are also fastened directly to the cells, can be designed as rollers, rollers, wheel, sliding feet and / or rollers, rollers, wheels or sliding feet in guides. It is also possible to anchor the stand elements firmly, with predetermined breaking points can be provided. As a result, a possible deformation and movement of all sections are ensured in an impact, so that the overall construction can perform their task as possible.

All intermediate structural supports or all partial regions and / or the individual cells can have a jointly connecting holding device. The holding device has the task of ensuring a good conductivity of the crash cushion when it is hit by the side of approaching vehicles. Furthermore, it can be ensured on the basis of the holding device that the damper arrangement does not yield when a vehicle drives into the construction laterally, while nevertheless ensuring that the remaining cell properties remain unchanged. Even in the case of a head-on impact, it is not possible for the sub-areas to move out of the construction and thereby fail to fulfill their task as intended.

At the end, the impact damper has a support device, a so-called. Endabstützung, which is realized either by supporting struts, which are at a certain angle to the roadway, or a solid wall on.

Advantageous embodiments and features will become apparent from the following description of exemplary embodiments, which are explained in conjunction with the drawings.

Brief description of the figures

Show it:

1 and 2 a crash cushion of the prior art,

3 a side view of a crash cushion according to the invention with different heights of the cells,

4 a top view of a crash cushion according to the invention with three sections, detail views and an energy diagram,

5 a top view of another embodiment of a crash cushion with different internal structure elements,

6 a side view of a crash cushion with different filling heights of the cells,

7 a schematic representation of the use of the impact absorber according to the invention as an initial or final construction in laterally arranged next to the traffic route vehicle restraint systems.

Detailed description of embodiments illustrated in the figures

3 shows a first embodiment of a crash cushion ( 1 ) in a schematic side view in front of an end support ( 14 ).

Depending on the condition of the traffic route, the impact absorber consists of cells arranged one behind the other in series ( 20 ), also called damping elements, wherein a plurality of such rows can be provided parallel to each other. According to the traffic route guidance, a V-shaped arrangement of the cells with different opening angles can also be selected.

In the illustrated embodiment of the arrangement, the impact damper 13 double rows cells ( 20 ) and a single cell ( 2 ) on the impact head. These cells are in the illustrated embodiment, cylindrical tubes and oriented so that their axis of symmetry are at right angles to the direction of the road. The individual cells are kept at a certain height, which is less than the average clear height of a car.

Furthermore, in 3 to recognize a subdivision of the arrangement into three partial areas, namely into a head area ( 9 ), an end region ( 10 ) and a middle area ( 11 ). In principle, each partial region comprises at least one cell according to the invention, so that the smallest possible arrangement has three cells.

In this particular embodiment of the invention, eleven cells account for the head area ( 9 ), eight to the end area ( 10 ) and eight to the middle section ( 11 ), wherein a smaller or larger number of cells is also conceivable.

In this preferred embodiment, the cells according to the invention have a greater height in the middle region than in the end region. It is also larger than the cells in the head area. Because of this arrangement, it is possible to predetermine the energy dissipation capacity associated directly with the mold within the array and place it according to the midrange (FIG. 10 ) in a targeted manner.

Supporting elements ( 4 ), which at the end of a Zwischenbaustütze ( 18 ) or on a cell ( 20 ), stand elements ( 5 ), which may be implemented in various ways. So it is possible that the stand elements ( 5 ) Have rollers, rollers, wheels or sliding feet. This ensures a mobility of the entire construction in all directions in the event of an impact, as a result of which the energy-dissipating capacity of all cells is utilized in the best possible way. Furthermore, it is also possible that the stand elements are fixed with immovable anchoring in the ground, but then have predetermined breaking points. Also fixed to the ground guide rails for a controlled guiding of the stand elements in an impact are possible.

The overall construction may have as a lateral boundary at least one side plate arrangement ( 6 ), which at the level of the cells and to the cells by means of fastening means such. As screws or welding are attached.

Furthermore, at least one ground anchor ( 7 ) for the at least one common holding device ( 8th ) to recognize.

The cells ( 20 ) are of the at least one common holding device ( 8th ) are held so that they can not escape in the event of an impact, which does not take place exactly in the direction of the axis of symmetry, and thus the predetermined energy reduction can take place in the desired manner.

Also in the embodiment according to 4a The arrangement of the cells, which are also formed here by cylindrical tubes, divided into three sub-areas, namely in a head area ( 9 ), an end region ( 10 ) and a middle area ( 11 ).

In the enlargements, which relate in each case to the head, middle and end, the different thicknesses (d1, d2, d3) of the wall of the cylinder tubes are shown. Here, the thickness of the tube wall of the cylindrical cells in the middle region ( 11 ) the biggest. In the end area ( 10 ) have the Cells have a thickness of the tube wall that is less than that of the cells of the middle region ( 11 ). The pipe wall thickness of the end region does not have to fall back to a thickness of the head region, which is also lower than in the middle region, but may also have a different pipe wall thickness. However, this is always less than that of the cells of the middle region. Thus, since the thickness of the tube wall is a measure of the deformation behavior, the thickness corresponding to a desired energy dissipation capacity can be selected.

In the event that another was chosen instead of the cylindrical shape, the wall thickness is one equivalent of the thickness of the tube wall.

Consequently, it is conceivable for the wall thickness as well as for the thickness of the pipe wall that the wall thickness or the thickness d4 in 4b does not decrease over the entire circumference, but only decreases at a location relevant to the deformation process, so as to ensure weakening in relation to a preceding cell or damper ( 4b ).

A cell with a greater wall thickness or thickness of the tube wall has a greater energy removal capacity and thus requires more energy to deform, this can be outlined by a curve of the potential energy dissipation capacity of the individual sections. The diagram 4 clearly shows the peculiarity of the invention, namely a lower capacity in the end. In addition, it is advantageous if the energy reduction capacity increases starting from the impact head or head region to the middle region. Likewise, it is also possible for the energy reduction capacity to remain essentially constant in the middle area and / or in the head area before the end area.

Determining now the peculiarity of the present invention from the above description, it can be seen that this is the decrease of the energy-depleting capacity before final support ( 14 ), so in the end, is.

For the transition of the individual sections or the individual cells of a high energy reduction capacity to a lower or vice versa, it is z. B. conceivable that a cylindrical cell ( 20 ) out 3 rotated by 90 °, whereby its axis of symmetry is oriented parallel to the direction of impact.

As a result, the cylindrical cell has a heavier deformability in the direction of the road. In this way, it is possible to achieve an increase or a reduction of the energy reduction capacity only by rotation from two identical damping elements, which leads to a cost saving.

5 shows a crash cushion similar construction as in 4 shown. A rotated cell ( 12 ) with a smaller cross-section is arranged so that it is parallel to the impact direction with its axis of symmetry.

Also revealed 5 in that, instead of a cylindrical cell, the impact absorber comprises a cuboidal cell ( 13 ). This can be z. B. then be required if a cell several steaming body such. B. foam in its interior should have. By means of this particular embodiment, an increase of the energy reduction capacity can also be achieved. So a square cell ( 13 ) with less capacity z. B. contain a few long elliptical elements, as in section AA (i) or with more energy reduction capacity several z. B. contain long cylindrical elements as in section AA (ii), (iv) or (v). A different spatial orientation of the elements in the interior is conceivable in order to achieve an increase or decrease of the energy reduction capacity with identical shape, as described above.

Furthermore, z. B. a filling with a filler such. For example, foam can increase energy removal capacity (section AA (iii) and detail A (i) in plan view of a cylindrical cell). Reinforcing internal structure elements ( 17 ) in the elements are also possible, like 5 and detail B (ii). In this case, different energy-dissipation capacities can also be achieved on the basis of varying reinforcing internal structure elements (details B (ii) and C (iii)), whereas the preferred embodiment or orientation of the internal structure elements is parallel to the impact direction.

Further, part or all of the cell may comprise a material (section A-A (vi)) which converts the impact energy into the decay of its predetermined shape. In this case, different energy levels are possible, so that this element also finds its way into the explained energy reduction capacity structure. Thus, varying power dissipation capacities can be realized in this way.

The structures described above are not limited to a cylindrical or angular outer shape, but other variants can be used and combined with each other. A combination of pipes and filler inside a cell is also possible. An angular, cuboidal cell need not necessarily be as described above, so such an element can also completely comprise a special material which can absorb a certain amount of energy, which is converted into the decay of its structure.

5 also shows reinforcing outer structure elements ( 19 . 19 ' ) which, in addition to the contact line of adjacent cylindrical cells, provide another means of transferring energy from one cell to the other. These external structural elements consist of plates which are welded between two adjacent cells along opposite generatrices. These plates may have different thicknesses in the different areas.

In this way, one can shape the energy reduction capacity and let a weaker capacity for the energy reduction follow on to a stronger one in the impact direction ( 5 Enlargement). It is also possible the energy reduction capacity of the external structure elements ( 19 . 19 ' ) of the successive cells, the energy dissipation capacity being lower, higher or between the energy dissipation capacity of two consecutively mounted cells (FIG. 20 ).

An end support ( 14 ) supports the entire crash cushion and absorbs the forces introduced into the crash cushion in the event of an impact.

6 shows a further embodiment of the invention in a damper of the type according to 1 , For the desired energy reduction capacity container-shaped cells are filled. Different filling heights or filling materials provide the different energy reduction capacities. For this purpose, z. B. suitable filling material of any kind can be used.

7 shows the use of the crash cushion according to the invention as a starting or final construction in a vehicle restraint system next to a traffic route. Usually such vehicle restraint systems are arranged as a guard rail boundary next to the road. Such vehicle restraint systems serve to divert stray vehicles from the road and to guide them back in the direction of travel on the road. Such systems can be made both of steel structures but also of concrete. The illustrated embodiment 1 shows a one-sided arrangement next to the road, the embodiment 2 shows an arrangement of such a vehicle restraint system between two opposite lanes. Such vehicle restraint systems form at the beginning of their mission as well as at the end of each a dangerous obstacle. Therefore, such vehicle restraint systems are protected at the beginning and also at the end with so-called initial constructions or end constructions, which are also referred to as terminal.

The impact absorber construction according to the invention can also be used as such an initial construction in a corresponding construction. In this case, symmetrically designed structures or so-called one-sided constructions can be used, in which only on the side facing the traffic route of the initial construction a protective device, ie a guard rail arrangement is provided on the opposite side but not. Such a construction is schematically in the third embodiment of 7 played.

The invention is not limited in its execution to the above-mentioned preferred embodiments. Rather, a number of variants is conceivable, which makes use of the illustrated solution even with fundamentally different types of use. Thus, it is within the scope of the described invention to vary the energy removal capacity within the head, middle and end regions.

LIST OF REFERENCE NUMBERS

1

crash cushions

2

Cell of the impact head

3

deflecting

4

support element

5

standing element

6

side plates

7

ground anchor

8th

holder

9

Area behind the impact head

10

end

11

the central region

12

rotated cell

13

cuboid cell

14

end support

15

Opening for guidance

16

curved safety barrier

17

reinforcing internal structure element

18

Zwischenbaustütze

19

reinforcing outer structure element

20

Cell, also called damping element

21

elastic cylinder

22

container-shaped cells

Claims (13)

Impact absorbers in front of obstacles next to traffic routes with a predetermined energy reduction capacity, with a head area ( 9 ), an end region ( 10 ) and an intermediate middle region ( 11 ), characterized in that the energy reduction capacity in the end region ( 10 ) of the impact damper is lower than in the middle region ( 11 ). Impact damper according to claim 1, characterized in that the energy reduction capacity of the Impact damper is lower at the beginning in the head area than in the central area. Impact damper according to one of claims 1 to 2, characterized in that the energy reduction capacity of the impact absorber from the head area ( 9 ) to the middle area ( 11 ) increases. Impact damper according to one of claims 1 to 3, characterized in that the energy reduction capacity of the impact absorber in the central region ( 11 ) is substantially constant. Impact damper according to at least one of the preceding claims 1 to 4 with successively arranged, deformable, energy-converting cells ( 20 ), which in some cases have a different energy-dissipating capacity, characterized in that at least one of the successive cells in the end region has a lower energy-dissipating capacity than at least one cell in the central region ( 11 ). An impact damper according to any one of claims 1-5, wherein at least one of the cells is formed as a tubular cylinder, characterized in that the thickness of the pipe wall provides the energy dissipation capacity of the at least one cell. Impact damper according to claim 1-5, characterized in that the energy dissipation capacity of the successive cells due to at least one point with a smaller wall thickness decreases. Impact damper according to at least one of the preceding claims, with energy-dissipating material within the cells, characterized in that at least one of the cells is at least partially filled with energy-dissipating material. Impact damper according to at least one of the preceding claims, wherein a cylindrical or cuboid cell is oriented with its center line perpendicular to the ground, characterized in that the successive cells have different heights or different filling heights, which determine the energy reduction capacity of the cell. Impact damper according to at least one of the preceding claims, wherein at least one of the cells has at least one reinforcing internal structure element ( 17 ) inside, characterized in that the energy dissipation capacity of the successive cells is influenced by means of the at least one reinforcing internal structure element. Impact damper according to at least one of the preceding claims, wherein at least one of the cells, an energy-dissipating material, which converts the absorbed energy in the decay of its structure, characterized in that the successive cells comprise at least one material having a lower energy dissipation capacity. Impact damper according to at least one of the preceding claims, wherein external structural elements ( 19 ) an additional possibility of forming an energy removal capacity outside a cell ( 20 ), characterized in that the successive cells have at least one outer structural element ( 19 ), which is equipped with a power dissipation capacity which is lower, higher or between the energy dissipation capacity of two consecutively attached cells ( 20 ) lies. Impact damper according to at least one of the preceding claims, characterized in that it is used as a start and / or end construction in a laterally arranged next to traffic routes vehicle restraint system.

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