Vehicle impact attenuator

Abstract

A vehicle impact attenuator includes a rail and at least one guide member moveable along the rail. At least a portion of the guide member is rotatable relative to the rail about a vertical axis by at least ±10° without binding the guide member against the rail. At least one energy absorbing element is located adjacent said guide member. A method of attenuating the impact of a vehicle is also provided.

Description

46 47. If desired, extra redirecting cylinders 48 may be positioned between the tubes 16.

FIGS. 10 and 11 relate to a third embodiment that is similar to the embodiment of FIG. 9 in many ways. FIG. 10 shows the system prior to impact with a vehicle, and FIG. 11 shows the system following an axial impact. Note that the compression elements 24 are designed to resist collapse of the tubes 16 in the lateral direction, while allowing expansion of the tubes 16 in the lateral direction.

The embodiment of FIGS. 10 and 11 uses a modified compression element 24 that is telescoping and is secured at both ends to the tube 16. FIG. 12 shows the telescoping compression element in its initial condition, and FIG. 13 shows the telescoping compression element during an axial impact when the tube 16 is elongated. If desired a tension spring 50 can be provided to restore the distorted tube 16 to the initial condition of FIG. 12 after an impact. The telescoping compression element of these figures can be used in any of the embodiments described above.

Of course, many changes and modifications can be made to the preferred embodiments described above. For example, when the elongated structure is implemented as a rail, two or more rails can be used rather than the single rail described above. The tubes 16 can be formed of a wide variety of materials, and may be non-circular in cross section (e.g. rectangular, oval, or triangular). The compression elements can be shaped either as frames or struts, as described above, or alternately as panels or other shapes designed to resist compression effectively. In some cases, a single compression element can be placed within each tube. In other cases, multiple compression elements may be placed within each tube, for example at varying heights.

Similarly, the guides described above can take many forms, including guides adapted to slide along a cable as well as guides adapted to slide along one or more rails. The guides may or may not include transverse elements, and if so the transverse elements may be shaped differently than those described above. For example, rigid panels may be substituted for the disclosed frames.

As another alternative, a separate guide may be provided for each tube rather than having a single transverse element to which multiple tubes are mounted. Also, there may be a smaller ratio of guides to tubes such that some of the tubes are coupled only indirectly to one or more guides (e.g. via intermediate tubes). In this alternative, two or more tubes that are spaced along the longitudinal axis of the array may have no guide therebetween.

The angle of the compression axes, the number of transverse elements 34 per system, the number of tubes per system, the location of the compression elements within the tubes, and the number of compression elements per tube may all be varied as appropriate for the particular application. Also, it is not essential that every tube include a compression element or that every tube be directly connected to a guide, and selective use of compression elements and/or guides with only some of the tubes is contemplated.

As used herein, the term “tube” is intended broadly to encompass tubes of any desired cross-section. Thus, a tube does not have to be circular in cross-section as in the illustrated embodiment.

The term “set” is used in its conventional way to indicate one or more.

The term “compression element” is intended to encompass a wide variety of structures that effectively resist compressive loads along a compression axis while allowing substantial compression transverse to the compression axis.

The foregoing detailed description has discussed only a few of the many forms that this invention can take. For this reason, this detailed description is intended by way of illustration, and not limitation. It is only the following claims, including all equivalents, that are intended to define the scope of this invention.

Claims

1. A vehicle impact attenuator comprising:

a rail comprising a side;

a plurality of transverse elements guided for sliding movement along the rail in a longitudinal direction, each transverse element loosely fitted to the rail such that each transverse element is free to twist about a vertical axis by at least ±10° without binding against the rail, and wherein each transverse element cooperates with said side of said rail such that each transverse element is restrained by said rail from being translated a substantial amount in a lateral direction relative thereto; and

a plurality of energy absorbing elements disposed between the transverse elements.

2. The invention of claim 1 wherein each transverse element is free to twist about the vertical axis by at least ±20° without binding against the rail.

3. The invention of claim 2 wherein each transverse element is free to twist about the vertical axis by at least ±25° without binding against the rail.

4. A vehicle impact attenuator comprising:

a rail comprising a side;

at least one guide member moveable along said rail in a longitudinal direction between at least a first position and a second position, wherein at least a portion of said guide member is rotatable relative to said rail about a vertical axis by at least ±10° without binding said guide member against said rail as said guide member is moved between at least said first and second positions, and wherein said at least one guide member cooperates with said side of said rail such that said at least one guide member is restrained from translating a substantial amount in a lateral direction relative thereto; and

at least one energy absorbing element located adjacent said guide member.

5. The invention of claim 4 wherein said at least one guide member comprises at least a pair of guide members spaced apart along said rail, wherein said at least one energy absorbing element is positioned between said spaced apart guide members.

6. The invention of claim 4 wherein said at least one guide member comprises a transverse element coupled to said at least one energy absorbing element.

7. The invention of claim 4 wherein said rail comprises opposite sides, wherein said at least one guide member comprises a pair of engagement members positioned on said opposite sides of said rail, each of said engagement members having an innermost end spaced apart from one of said opposite sides of said rail respectively such that said guide member can rotate relative to said rail.

8. The invention of claim 7 wherein said rail comprises a vertically oriented central rib defining said opposite sides and a pair of horizontal flanges extending from said opposite sides of said central rib, wherein said engagement members are positioned on said opposite sides of said central rib and below said horizontal flanges, with said innermost ends of said engagement members spaced apart from said opposite sides of said central rib, and wherein said engagement members are engageable with said horizontal flanges to prevent said at least one guide member from dislodging from said rail.

9. The invention of claim 4 wherein said at least one guide member is rotatable relative to said rail about said vertical axis by at least ±20° without binding against said rail.

10. The invention of claim 4 wherein said at least one guide member is rotatable relative to said rail about said vertical axis by at least ±25° without binding against said rail.

11. The invention of claim 4 wherein said at least one guide member extends transversely from said side of said rail.

12. The invention of claim 4 wherein said at least one energy absorbing element comprises a resilient, self-restoring tube.

13. The invention of claim 4 wherein said rail comprises opposite sides, wherein said at least one guide member comprises a pair of engagement members positioned on said opposite sides of said rail, each of said engagement members having an end portion facing one of said opposite sides of said rail respectively, wherein said end portions are shaped to permit rotation of said at least one guide member relative to said rail.

14. The invention of claim 13 wherein said end portions each comprise a curved portion.

15. The invention of claim 13 wherein said end portions each comprises at least one chamfered corner.

16. A method of attenuating the impact of a vehicle comprising:

providing an impact attenuator comprising a rail having a side, at least one guide member moveably coupled to said rail, and at least one energy absorbing element located adjacent said guide member;

impacting said impact attenuator with said vehicle;

moving said guide member along said rail in a longitudinal direction in response to said impacting said impact attenuator with said vehicle; and

rotating at least a portion of said guide member relative to said rail about a vertical axis by at least 10° without binding said guide member against said rail as said guide member is moved along said rail in said longitudinal direction; and

engaging said side of said rail with said at least one guide member and thereby preventing said guide member from translating a substantial amount in a lateral direction relative to said rail.

17. The method of claim 16 wherein said at least one guide member comprises at least a pair of guide members spaced apart along said rail, and wherein said at least one energy absorbing element is positioned between said spaced apart guide members.

18. The method of claim 16 wherein said at least one guide member comprises a transverse element coupled to said at least one energy absorbing element.

19. The method of claim 16 wherein said guide member comprises a pair of engagement members positioned on opposite sides of said rail, each of said engagement members having an innermost end spaced apart from said rail, wherein said rotating said guide member relative to said rail comprises moving said innermost ends toward said rail.

20. The method of claim 19 wherein said rail comprises a vertically oriented central rib and a pair of horizontal flanges extending from opposite sides of said central rib, wherein said engagement members are positioned on opposite sides of said central rib and below said horizontal flanges, with said innermost ends of said engagement members spaced apart from said central rib, and wherein said engagement members are engageable with said horizontal flanges to prevent said guide member from dislodging from said rail.

21. The method of claim 16 wherein said rotating said at least said portion of said guide member relative to said rail about said vertical axis comprises rotating said at least said portion of said guide member relative to said rail about said vertical axis by at least 20° without binding against said rail.

22. The method of claim 16 wherein said rotating said at least said portion of said guide member relative to said rail about said vertical axis comprises rotating said at least said portion of said guide member relative to said rail about said vertical axis by at least 25° without binding against said rail.

23. The method of claim 16 wherein said guide member extends transversely from opposite sides of said rail.

24. The method of claim 16 wherein said at least one energy absorbing element comprises a resilient, self-restoring tube.

25. The method of claim 16 wherein said impacting said impact attenuator with said vehicle comprises impacting said energy absorbing element with said vehicle.

26. The invention of claim 1 wherein said side is substantially vertical.

27. The invention of claim 4 wherein said side is substantially vertical.

28. The invention of claim 16 wherein said side is substantially vertical.

29. A roadway crash cushion, comprising:

an array of collapsible cells, each cell having an arch in at least opposite portions of the cell;

a plurality of guides disposed between the collapsible cells and coupled to the arches on the opposite portions of the cells, wherein the cells extend laterally outwardly from the guides coupled thereto such that the cells are positioned to transfer a lateral impact load applied by a vehicle to the guides; and

wherein each guide is guided for sliding along a longitudinal rail member extending along a center longitudinal axis of the crash cushion as the collapsible cells collapse, and wherein each guide cooperates with a side of the rail member such that the guide is restrained by the rail member from being translated in a lateral direction relative thereto.

30. The roadway crash cushion of claim 29, wherein the cells comprise an elastomeric material.

31. The roadway crash cushion of claim 29, wherein the cells comprise a polyethylene material.

32. A roadway crash cushion, comprising:

a pair of diaphragms each extending transversely relative to a longitudinal axis along which the roadway crash cushion collapses, the pair of diaphragms moveable relative to each other during an axial impact along the longitudinal axis;

a pair of energy absorbing elements disposed between the pair of diaphragms, each of the energy absorbing elements having an arch, wherein the pair of energy absorbing elements extend laterally outwardly from the pair of diaphragms; and

wherein each diaphragm is guided for sliding along a longitudinal rail member extending along a center longitudinal axis of the crash cushion as the collapsible energy absorbing elements collapse, and wherein each diaphragm cooperates with a side of the rail member such that the diaphragm is restrained by the rail member from being translated in a lateral direction relative thereto.

33. The roadway crash cushion of claim 32 wherein the diaphragms each comprise a rectangular member.

34. The roadway crash cushion of claim 32 wherein the energy absorbing elements each comprise an elastomeric material.

35. The roadway crash cushion of claim 32, wherein the energy absorbing elements each comprise a polyethylene material.

36. The roadway crash cushion of claim 32, wherein the energy absorbing elements flatten along the longitudinal axis when collapsing.

37. A roadway crash cushion, comprising:

a collapsible, substantially self-restoring portion comprising a plurality of energy absorbing elements each comprising a camber and formed substantially of a resilient polymeric material;

a plurality of guides, each of said guides disposed between, and secured to the cambers of, an adjacent pair of energy absorbing elements, wherein the adjacent pairs of energy absorbing elements extend laterally outwardly from the respective guides such that the energy absorbing elements are positioned to transfer a lateral impact load applied by a vehicle to the guides; and

a longitudinal, ground-mounted rail member extending along a center axis of the crash cushion and having a side, wherein the guides cooperate with the side of the rail such that the guides are restrained by the rail from being translated in a lateral direction relative thereto.

38. The roadway crash cushion of claim 37, wherein the resilient polymeric material comprises polyethylene.

39. The roadway crash cushion of claim 37, wherein the camber provides for the energy absorbing element to become elongated transverse to a longitudinal axis and flattened along the longitudinal axis.

40. The roadway crash cushion of claim 37, wherein the guide comprises a laterally extending plate member disposed under an elevated surface of the rail.

41. The roadway crash cushion of claim 37 wherein the guides are secured to the energy absorbing elements with bolts passing through holes in the energy absorbing elements.