The present invention relates generally to an impact attenuator, for example a crash cushion configured with side panels moveable relative to each other.
Crash cushions have been used for many years to protect errant vehicles from rigid structures along roadways. Bridge piers, bridge abutments, light poles and other roadway appurtenances are typically shielded from errant vehicles using crash cushions. A crash cushion may perform this task primarily in at least two ways. First, an errant vehicle that impacts a crash cushion head on may be safely decelerated by compression of the crash cushion. Second, a vehicle that impacts the side of a crash cushion may be safely redirected away from the hazard in a stable manner that minimizes the chance the vehicle will subsequently roll.
While many redirective side impacts occur upstream of the protected hazard (i.e. a “right-way” impact), crash cushions may be installed between two-way or bidirectional traffic. In these situations, there exists the possibility of a reverse direction redirective side impact, whereby the impacting vehicle strikes the crash cushion after passing by the hazard. Typically, the side panels of a crash cushion are longitudinally overlapped in such a way so to prevent the vehicle from snagging on the side panels during a right-way impact. In those situations where the crash cushion has bidirectional traffic, however, there may be one side of the crash cushion where the side panels are not longitudinally overlapped in the most advantageous way to prevent vehicle snagging.
This potential for snagging may be further influenced by the traditional shape of crash cushion side panels. Typically, side panels are formed with a constant formed shape along the length of the side panel, meaning the shape and height of the corrugations does not vary from the upstream end to the downstream end of the side panel. There are several reasons for this. First, the constant cross sectional shape enables the side panels to easily stroke rearward during a vehicle head on crash impacting the front of the crash cushion. Since the cross sectional shape is constant and does not vary, overlying panels can easily stroke rearwards without interfering with an underlying downstream panel. Second, many crash side panels are formed by rolling, which results in a constant cross sectional shape from front to back.
Crash cushions configured with side panels also are typically configured with the one more of the side panels arranged in a vertical plane. Such an arrangement may not optimize vehicle roll prevention during a side impact.
Thus, the need remains for an impact attenuator that improves redirection while diminishing the possibility of vehicle roll and reducing the possibility of vehicle snagging in a reverse impact event.
The present invention is defined by the following claims, and nothing in this section should be considered to be a limitation on those claims.
In one aspect, one embodiment of a crash cushion includes first and second diaphragm frames each having first and second laterally spaced sides defining first and second planes sloping inwardly from a top to a bottom of each side of the first and second diaphragm frames. The first diaphragm frame is moveable relative to the second diaphragm frame in response to a head-on impact. First and second side panels are attached respectively to the first and second sides of the first and second diaphragm frames, wherein the first and second side panels are moveable relative to the second diaphragm frame in response to the head-on impact.
In another aspect, one embodiment of an impact attenuator includes first, second and third longitudinally spaced frames. A first side panel is attached to the first and second frames, and a second side panel is attached to the second and third frames. The first and second side panels are moveable relative to the second and third frames respectively in response to a head-on impact. Each of the first and second side panels includes a first cross sectional shape at an upstream end of the side panel, a second cross sectional shape at a midpoint of the side panel and a third cross sectional shape at the downstream end of the side panel. The first, second and third cross sectional shapes are different. In one embodiment, the first, second and third cross sectional shapes have first, second and third heights, wherein the third cross sectional height is greater than the second cross sectional height. In one embodiment, the second cross sectional height is greater than the first cross sectional height.
In yet another aspect, one embodiment of a crash cushion includes first and second laterally spaced rails and first and second diaphragm frames each having first and second laterally spaced sides. At least the first diaphragm frame includes laterally spaced first and second sets of a plurality of longitudinally spaced apart guides slidably engaging the first and second rails respectively. The first diaphragm frame is moveable relative to the second diaphragm frame in response to a head-on impact. First and second side panels are attached respectively to the first and second sides of the first and second diaphragm frames, wherein the first and second side panels are moveable relative to the second diaphragm frame in response to the head-on impact.
Various methods of using and assembling the impact attenuator, or crash cushion, are also provided.
The impact attenuator, including the disclosed crash cushion, provides significant advantages relative to existing crash cushion designs. The side panels improve the performance of reverse direction redirective impacts due to the close nesting of the panels, which reduces the chances of components of the vehicle snagging on the crash cushion. The tilt of the side panels also reduces the likelihood of an impacting vehicle rolling substantially during the redirective side impacts, which subsequently also reduces the likelihood of the vehicle rolling upon exiting the crash cushion. Moreover, the side panels, and interface therebetween, increases the energy absorbed by the side panels during end on impacts through a combination of slots, tabs that break, and an interference fit between the panels as the side panels are stroked relative to each other. This innovative combination of energy absorption mechanisms works to bring the vehicle safely to a stop during end-on impacts.
The foregoing paragraphs have been provided by way of general introduction and are not intended to limit the scope of the following claims. The various preferred embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.
It should be understood that the term “plurality,” as used herein, means two or more. The term “longitudinal,” as used herein means of or relating to length or the lengthwise direction 2 of the crash cushion, or assembly thereof, and includes an axial, end-on impact direction. During an end-on impact, the system dissipates the energy of the impacting vehicle. The term “lateral,” as used herein, means directed between or toward (or perpendicular to) the side of the crash cushion, for example the lateral direction 5, or a side impact direction. The term “coupled” means connected to or engaged with, whether directly or indirectly, for example with an intervening member, and does not require the engagement to be fixed or permanent, although it may be fixed or permanent, and may include an integral connection wherein the features being coupled are portions of a single, unitary component. The term “transverse” means extending across an axis, and/or substantially perpendicular to an axis. It should be understood that the use of numerical terms “first,” “second,” “third,” etc., as used herein does not refer to any particular sequence or order of components; for example “first” and “second” side panels may refer to any sequence of such side panels, and is not limited to the first and second side panels of a particular configuration unless otherwise specified. The terms “upstream” 400 and “downstream” 402 refer to directions relative to the impact direction of a vehicle, for example with a backstop 30 and/or rear anchor 416 being downstream of the front anchor 404, or front of the crash cushion. The terms “inboard” and “outboard” are defined in the lateral direction relative to a centerline longitudinal axis 482, with “inboard” referring to a component or feature being closer to the centerline axis 482, and “outboard” referring to a component or feature being further from the centerline axis. The phrase “impact attenuator” refers to a structure, assembly and/or system that absorbs or attenuates the energy of an impacting vehicle, whether in a head-on, right-way or wrong-way side redirective impact event. The impact attenuator includes two-sided crash cushions, and one-sided guard rail systems.
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A plurality of side panels 13, 14, 15, and 16 are connected to, and extend longitudinally between adjacent pairs of diaphragm frames 11, 7, thereby defining and forming bays 101. The side panels 13, 14, 15, 16 may be connected to both sides 430, 432 of the frames 11, 7, or to only one side, for example a post of a guardrail system. In addition, a plurality of side panels 13, 14, 15, 16 may be connected to each side of each pair of adjacent frames 11, 7. For example, as shown in
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The upstream end 105 of side panel 13, 15 has a mounting hole 107 to facilitate attaching the side panel 13, 15 to an upstream diaphragm frame 7. The downstream end 106 of side panel 13, 15 has partial mounting hole 110 for mounting the downstream end 106 of the side panel 13, 15 downstream to an adjacent diaphragm frame 7. A slot 108 is positioned in the center of the side panel 13, 15 and acts as a guide for the fastener 6 as the side panel 13, 15 is stroked during an end-on impact. The partial mounting hole 110 is joined to the slot 108 by a restriction opening 109, or narrower neck portion of the slot. The restriction 109 acts to hold the side panel 13, 15 in a fixed location until a predetermined force is achieved during the axial head-on impact. In this embodiment, the restriction 109 narrows the partial mounting hole 110 to a ½ inch, however this distance may be greater or lesser, depending upon the level of predetermined load that is desired. As shown in
The side panel 13, 15 has a first cross sectional shape A1 at an upstream end 105 of the side panel, a second cross sectional shape A2 at a midpoint of the side panel and a third cross sectional shape A3 at the downstream end 106 of the side panel, wherein the first, second and third cross sectional shapes A1, A2, A3 are different. In one embodiment, the first, second and third cross-sectional shapes A1, A2, A3 have first, second and third heights, and wherein the third height H3 is greater than the second height H2, and the second height H2 is greater than the first height H1. In one embodiment, the side panel 13, 15 has a constant thickness (e.g., 3/16 inches), and a constant width W (e.g., 2 11/16 inches), but the upstream end 105 has a first height H1, the midpoint has a second height H2, and the downstream end 106 has a third height H3, wherein the third height H3 is greater than the second height H2, and the second height H2 is greater than the first height H1. In one embodiment, the outer dimension of the upstream end of crests 124 of the side panel 13, 15 is 3 11/16 inches, while the panel has an overall length of 32 inches. It should be understood that the side panels may have other suitable shapes and sizes. The other side panels 14, 16 may be configured with similar cross-sectional shapes A1, A2, A3 and heights H1, H2, H3. It should be understood that the phrase “cross sectional shape” refers to the shape of the cross section, including for example and without limitation the height, width, web thickness, depth of the valleys/peaks, etc. at the cross section, and does not equate to area, although the areas may also be different or the same.
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In this way, the impact attenuator includes first longitudinally spaced frame 11 and second and third longitudinally spaced frames 7, a first side panel 15 attached to the first and second frames, and a second side panel 13 attached to the second and third frames, wherein the first side panel 15 is moveable relative to the second side panel 13 from a pre-impact position to an impact position in response to a head-on impact. The downstream end 106 of the first panel 15 overlaps the upstream end 105 of the second panel 13 in a non-interference configuration in the pre-impact position, as shown for example in
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One method of redirecting a vehicle impacting the side of a crash cushion includes impacting the side panel 15, 13, 16, 14 with a vehicle 201, wherein the side panel is attached to sides of adjacent first and second diaphragm frames 11, 7 each defining the plane P1, P2 sloping inwardly from a top to a bottom of the sides of the first and second diaphragm frames. The first diaphragm frame 11, 7 is moveable relative to the second diaphragm frame 7 in response to a head-on impact, and the side panel 15, 13, 16, 14 is moveable relative to the second diaphragm frame 7 in response to the head-on impact. The method further includes redirecting the vehicle 201 with the side panel(s) 15, 13, 16, 14.
Another method of attenuating energy of a vehicle impacting a crash cushion includes impacting the crash cushion head on and moving a first frame 11, 7 relative to a second frame 7 and a third frame 7, wherein the first, second and third frames are longitudinally spaced. The method further includes sliding a first side panel 15, 13, 16, 14 attached to the first and second frames relative to a second side panel 1316, 14 attached to the second and third frames, wherein each of the first and second side panels comprises a first cross sectional shape A1 at an upstream end of the side panel, a second cross sectional shape A2 at a midpoint of the side panel and a third cross sectional shape A3 at the downstream end of the side panel, wherein the third cross sectional shape A3 is different than the second cross sectional shape A2. In one embodiment, the third cross sectional shape A3 has a height H3 that is greater than the height H2 of the second cross sectional shape A2.
A method of attenuating energy of a vehicle impacting a crash cushion head on includes moving a first frame 11, 7 relative to a second frame 7, wherein the first and second frames are longitudinally spaced, and wherein the first frame includes a plurality of longitudinally spaced apart guides 12. The method further includes sliding the guides 12 and first frame 11, 7 relative to a rail 420 supporting the first frame 11, 7, wherein the guides 12 are engaged with the rail 420. The method further includes sliding a side panel 15, 13, 14, 16 attached to the first frame relative to the second frame.
Although the present invention has been described with reference to preferred embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. As such, it is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is the appended claims, including all equivalents thereof, which are intended to define the scope of the invention.
This application claims the benefit of U.S. Provisional Application No. 63/619,826, filed Jan. 11, 2024.
Number | Date | Country | |
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63619826 | Jan 2024 | US |