Crash buffer

Abstract

A crash cushion includes a first track segment and a second track segment that overlap and are coupled by a fastener. The first track segment is movable relative to the second track segment from a pre-impact position to an impact position in response to an axial impact on a guardrail assembly. The first track segment includes an elongated slot aligned with the fastener and having a first length. A support post is releasably connected to the first track segment and is capable of rotating to a collapsed position after the first track segment has moved a first travel distance, wherein the first length is greater than or equal to the first travel distance.

Description

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 035,414, filed on June 5, 2020, entitled “Crash Cushion,” the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] The present invention relates generally to crash cushions and, in particular, to crash cushions configured with guardrails to mitigate high energies during telescoping. Background Art

[0003] Crash buffers comprising guardrails having terminal ends can be used along highways in front of obstacles such as concrete walls, toll booths, tunnel entrances, bridges, etc. to protect drivers of errant vehicles. In some systems, the crash buffer can include a guardrail assembly that is, for example, configured with a guardrail end treatment that is capable of absorbing and distributing axial impact loads. Such a guardrail system can include a plurality of panels configured with grooves. During an axial impact, the energy of the moving vehicle is attenuated by friction between the panels and by shearing the panel material between the grooves. At the same time, these systems can include support columns that support the panels. The support columns can be configured to break during an axial impact. Finally, some systems include a deforming member that deforms one or more of the panels.

[0004] These various systems can have various drawbacks. For example, and without limitation, during an axial impact event, when a crash bumper is struck by a vehicle, there are several mechanisms for absorbing the energy of the impacting vehicle and generating a force that decelerates the vehicle. These impact forces or energy-absorbing mechanisms include the energy / force required to break tabs in the guardrail panel, the energy / force generated by friction in the panel, the energy / force required to deform the guardrail panel, and the energy / force required to knock down one or more split support posts. If all of these forces occur simultaneously, the system may exert a higher-than-desired deceleration force on the impacting vehicle, such as through a deceleration spike generated by the split support posts.

[0005] For example, the force that knocks over one or more support posts is a force that is typically not dissipated during the telescoping of the individual compartments of a crash cushion. The force that knocks over one or more posts is typically high, or peaks, when the posts are first impacted, and then decreases as the posts break away from the guardrail. This peak can complicate the design of crash cushions that utilize various energy dissipation mechanisms because the combined force resulting from the four forces when the posts are first impacted may be higher than desired.

[0006] Therefore, it may be desirable to provide a system that provides a smoother or more consistent deceleration force during an impact event. Summary of the Invention

[0007] The present invention is defined by the following claims, and nothing in this section should be taken as a limitation on those claims.

[0008] In one aspect, one embodiment of a crash buffer includes a first track segment having an upstream end portion, a downstream end portion, and a first side portion. A second track segment includes an upstream end portion, a downstream end portion, and a second side portion facing the first side portion of the first track segment. The upstream end portion of the second track segment overlaps the downstream end portion of the first track segment and is secured to the downstream end portion of the first track segment by a fastener. The first track segment is movable relative to the second track segment from a pre-impact position to an impact position in response to an axial impact on a guardrail assembly. The first track segment includes a plurality of longitudinally spaced slots aligned with and extending upstream of the fastener. The plurality of slots includes a first elongated slot aligned with the fastener when the first track segment is in the pre-impact position, wherein the first elongated slot has a first length. The first track segment is releasably connected to a support post, and the support post is rotatable from an upright position to a collapsed position. During an axial impact, the support post can be released from the first track segment and can be rotated to a collapsed position after the first track segment has moved a first travel distance, wherein the first length is greater than or equal to at least 75%, and more preferably 100%, of the first travel distance.

[0009] In another aspect, an embodiment of a crash cushion includes a support post that absorbs a first amount of energy when the support post is rotated to a collapsed position. A first pair of adjacent slots is separated by a tab, wherein the fastener engages the tab and absorbs a second amount of energy after the support post absorbs at least 75%, and more preferably 100%, of the first amount of energy.

[0010] In another aspect, one embodiment of a support column assembly includes a ground anchor and a support column having a front portion, a rear portion, and opposing side portions. The rear portion includes a pair of vertical slots and a hinge portion defined between the slots. The bottom of the hinge portion and at least one of the front portion and the side portion are connected to the ground anchor by a weld. The weld connecting at least one of the front portion and the side portion is capable of breaking when the support column is able to rotate about the hinge portion from an upright position to a collapsed position.

[0011] In yet another aspect, an embodiment of a method for absorbing energy from an impact vehicle includes: impacting an impact head portion of a crash bumper to slide a first track segment from a pre-impact position to an impact position relative to a stationary second track segment, wherein the first track segment and the second track segment are coupled by a fastener. The method further includes sliding the fastener in a slot defined in the first track segment, wherein the slot has a first length, and rotating a support post connected to the first track segment from an upright position to a collapsed position after the first track segment has moved a first travel distance, wherein the first length is greater than or equal to at least 75% of the first travel distance. In one embodiment, the second track segment includes a deformable member secured thereto, and the first track segment has a second elongated slot aligned with the deformable member, wherein the second elongated slot has a second length greater than or equal to at least 75% of the first travel distance.

[0012] Various aspects and embodiments provide significant advantages. For example, sizing the slots in the panels so that the deforming members on the stationary panel cannot deform the panel until the support posts separate, modulating the energy peak generated by the support post separation force and not increasing the energy peak generated by the support post separation force. Similarly, the spacing of the tabs in the guardrail panel can be configured so that the tabs are not sheared until the support post has fallen or is almost fallen. In addition, portions of the welds securing the support post to the ground anchor can be removed or minimized, for example, along the front, side, or rear, so that less force is required to knock over the support post, thereby absorbing a corresponding amount of energy. These various alternatives can be used alone or in conjunction with one or more of the other alternatives to achieve the desired results, thereby allowing the user to adjust the system.

[0013] The foregoing paragraphs have been provided by way of general introduction and are not intended to limit the scope of the appended claims. Various preferred embodiments and further advantages will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a perspective view of one embodiment of a crash buffer.

[0015] Figure 2 yes Figure 1 Side view of the crash buffer shown in .

[0016] Figure 3 yes Figure 1 A top view of the collision bumper in .

[0017] Figure 4 yes Figure 1 Rear end view of the crash buffer shown in .

[0018] Figure 5 yes Figure 1 A front end view of the crash buffer shown in FIG.

[0019] Figure 6 is a side view of one embodiment of a track segment.

[0020] Figure 7 is a side view of another embodiment of a track segment.

[0021] Figure 8 is a partial top perspective view of a pair of support columns mounted to a track section.

[0022] Figure 9 is a partial perspective view of an impact head mounted to a pair of track sections.

[0023] Figure 10 is a fragmentary perspective view showing the connection of a spacer and a track segment, wherein fasteners secure overlapping end portions of the track segments.

[0024] Figure 11A is a top perspective view of the crash bumper before the impact head engages the downstream bulkhead.

[0025] Figure 11B is a top perspective view of the crash bumper immediately after the impact head engages the downstream bulkhead.

[0026] Figure 12 is an enlarged fragmentary end view showing the connection between the spacer and the support post.

[0027] Figure 13A It is a partial perspective view of the support column assembly before impact.

[0028] Figure 13B It is a partial perspective view of the support column assembly after the impact.

[0029] Figure 14A is a partial perspective view of a track segment with a deformation member located underneath another track segment in a pre-impact configuration.

[0030] Figure 14B yes Figure 14A A partial perspective view of the track segment shown in FIG. 1 during an impact event.

[0031] Figure 15 is a partial side view showing overlapping track segments including deformable members.

[0032] Figure 16A is a partial rear perspective view of the support strut assembly in a pre-impact configuration.

[0033] Figure 16Bis a fragmentary rear perspective view of the support strut assembly during an impact event as the support strut rotates to a collapsed position.

[0034] Figure 17 is a deceleration diagram showing the impact response of a pair of support struts (single diaphragm) during an impact.

[0035] Figure 18 is a side view showing the first compartment. DETAILED DESCRIPTION

[0036] It should be understood that the term "plurality" as used herein means two or more. The term "longitudinal" as used herein means or relates to the length or longitudinal direction 2 of a crash buffer or a component of a crash buffer, and includes an axial end impact direction. During an end impact, the system dissipates energy of the impacting vehicle as the system telescopes and contracts. The term "lateral" as used herein means oriented between or toward (or perpendicular to) the sides of the crash buffer, such as in a lateral direction 4 or a side impact direction. The term "coupled" means connected or joined directly or indirectly, such as with an intermediate member, and does not require the joint to be fixed or permanent, however the joint can be fixed or permanent and can include an integral connection where the features being connected are part of a single integral component. The term "transverse" means extending across an axis and / or substantially perpendicular to an axis. It should be understood that, unless otherwise indicated, the use of the numerical terms "first," "second," "third," etc., as used herein, does not refer to any particular order or sequence of components; for example, "first" and "second" connector sections may refer to any order of such sections and are not limited to a first connector section and a second connector section of a particular configuration. The terms "upstream" and "downstream" refer to directions relative to the direction of impact of the vehicle 12, such as where the backup member 14 and the rear anchor are located downstream of the impact head 18, or in front of the crash bumper 10. The terms "inboard" and "outboard" are defined as lateral directions relative to the centerline longitudinal axis 16, where "inboard" refers to a component or feature that is closer to the centerline axis and "outboard" refers to a component or feature that is farther from the centerline axis. The phrase "crash bumper" refers to a component or feature that is closer to the centerline axis. Figure 1 The double-sided system shown in FIG and also refers to a guardrail terminal system that is constructed with only Figure 1One side or half of the system shown. As used herein, the terms "deform," "deform," and "deformable," and variations thereof, mean to transform, shape, or bend without shearing. The term "overlapping" refers to two components or portions of two components being positioned relative to, on top of, or next to one another, and is independent of the lateral position of the overlapping components, wherein a portion of an upstream track segment "overlaps with a portion of a downstream track segment," and a portion of a downstream track segment "overlaps with a portion of an upstream track segment."

[0037] Figure 1 The crash cushion 10 disclosed in

[0015] provides a system that smoothes the energy dissipation curve by reducing / eliminating the forces applied by the shear fasteners 60 and the tabs 26, the start tabs 28, and / or the deforming members 30 during the time interval when one or more support posts 100 are being overwhelmed and absorbing energy. The support post assembly can also be configured to reduce the amount of force that knocks over or overwhelms one or more support posts. Various embodiments can be incorporated into a crash cushion or terminal section having overlapping fender panels or track sections 20 that absorb energy by shaping and / or shearing the material (e.g., the tabs 26, the start tabs 28) as the first panel slides over the second panel. The system is particularly well-suited for use in a staged crash cushion or terminal section in which only one compartment is compressed at a time.

[0038] Crash buffer 10( Figures 1 to 5 ) includes a plurality of guardrail panels, also referred to as track segments 20 ( Figure 6 and Figure 7 ) and includes a slot 22, a first elongated slot 24, a tab 26, and a starting tab 28. Some of the guardrail panels also include a deforming member 30 ( Figure 7 and Figure 15 ). The deforming member 30, which in one embodiment is configured as a shaped fin, provides a low-cost method for increasing the operating load of the crash cushion when impacted in the longitudinal direction. In one embodiment, the deforming member 30 is made of metal, such as, but not limited to, steel. The deforming member has a central portion 32 having an inclined leading edge 34 and a trailing edge 36 that intersect at a curved apex 38. The deforming member 30 is secured to the upstream end portion 50 of the track segment 20, such as by welding or by means of fasteners in the valley 82, wherein the deforming member 30 is formed of a metal such as, but not limited to, steel. Figure 15 As shown in FIG, the central portion extends laterally outward from the track segment. Deformable members are further described and disclosed in U.S. Patent No. 8,215,619, the entire disclosure of which is incorporated herein by reference.

[0039] In one embodiment, a crash buffer includes a first track segment having an upstream end portion 50, a downstream end portion 52, and a first inner side 54. A second track segment includes an upstream end portion 50, a downstream end portion 52, and a second outer side 56 facing the first inner side 54 of the first track segment. The upstream end portion 50 of the second track segment overlaps the downstream end portion 52 of the first track segment and is secured to the downstream end portion 52 of the first track segment by one or more fasteners 60. In one embodiment, the track segments are coupled by a total of eight (8) fasteners 60 defined by four rows of two (2) longitudinally spaced fasteners.

[0040] The first track segment is movable from a pre-impact position to an impact position relative to the second track segment in response to an axial impact of the guardrail assembly by a vehicle 12 moving in the longitudinal direction 2. It should be understood that the crash cushion may include several compartments (in Figures 1 to 3 ), each compartment is defined by a pair of laterally spaced track segments 20, an upstream partition 132, and a downstream partition 132, wherein the downstream partition defines the upstream partition of the next adjacent downstream compartment. It should be understood that the crash cushion can have more or less than five (5) compartments. It should also be understood that the track segment 20 of the upstream compartment is referred to as the first track segment, and the track segment 20 of the next adjacent downstream compartment is referred to as the second track segment. During an axial impact event, the compartments telescope sequentially, wherein the "first" track segment of the first compartment 70 slides past the "second" track segment of the second compartment 72. Next, the track segment 20 of the second compartment 72 becomes the "first" track segment that slides past the "second" track segment of the third compartment 74, and so on. Each track segment 20 includes at least one row of a plurality of longitudinally spaced slots 22, first elongated slots 24 that align with and extend upstream of one or more fasteners 60. In one embodiment, each track segment includes a plurality (shown as four) of vertically spaced rows of slots 22, first elongated slots 24. The plurality of slots in each row includes a first elongated slot 24 positioned at the downstream end portion 52 to align with the one or more fasteners 60 when the first track segment is in a pre-crash position, i.e., before the vehicle impacts the crash bumper, wherein the shortest first elongated slot 24 has a minimum first length L1 measured between the location (axis) of the first upstream fastener and the end of the first elongated slot 24. The first portion of the first elongated slot may be slightly enlarged to facilitate insertion and installation of the fastener 60.

[0041] like Figure 6As shown in FIG, each track segment 20 is preferably formed as a triple beam having three outwardly extending peaks 80 and two inwardly extending valleys 82, wherein a row of slots 22, first elongated slots 24, is formed in each of four walls 86 between one of the peaks and one of the valleys. Deformation members 30 are secured to the track segment in the valleys 82. It should be understood that the track segment can also be configured as a W-shaped beam having two peaks and one valley. During an impact event with equal clamping force, the triple beam has a greater amount of overlapping surface area and, therefore, greater friction and energy dissipation. Preferably, to smooth energy dissipation, the slots of the vertically spaced rows are horizontally staggered in the longitudinal direction, such that the slots 22 and tabs 26 in each row are vertically misaligned with the slots 22 and tabs 26 of any other row. The first elongated slots 24 in each row can have different lengths L1, such that the slots 22 of the immediately upstream row are staggered, for example, by a distance d1, relative to the slots 22 of the immediately adjacent row.

[0042] The first guardrail panel or first track section is attached to a mounting bracket 90, which is attached to the strike head 18, which may include a pair of panels or a pair of plates ( Figure 9 ). When struck by a vehicle, each successive upstream guardrail panel or first track segment slides over the downstream guardrail panel or second track segment in the immediately following bay, which remains stationary until the preceding bay telescopes and the impact head 18 strikes the support post 100 or the partition 132 partially defined thereby at the front of the immediately following bay. The guardrail panels or track segments 20 are attached to the spacers 94, which are attached to the split support posts 100 by shear bolts 96. For example, the guardrail in the first bay 70 (e.g., the first track segment) slides over the guardrail (the second track segment) of the second bay 72 ( Figure 11A and Figure 11B). Once this sliding is complete, the guardrail of the second compartment 72 (now the first track segment) slides over the guardrail of the third compartment 74 (the second track segment). The sliding guardrail panels or track segments are held to the other guardrail panels by bolts or fasteners 60 that clamp the two track segments together on each side of the compartment and create friction between the sliding track segments. A pair of brackets 98 overlie the valley and two rows of vertically spaced fasteners. Additionally, a cross member 99 extends laterally across the top of the partition and has opposite ends connected to the upper spacer 94 by a plurality of fasteners 101. The cross member 99 is not connected to the support column 100. The cross member can have a Z-shape or an L-shape and can include a lip 103 bent over the top and front of the support column that acts as a stop for engaging the support column and helps prevent the fasteners 60 from shearing until the support column 100 falls during an impact event. Also, because the cross member is not connected to the support columns / diaphragms, the lip will not interfere with or prevent the support columns / diaphragms from falling down.

[0043] The fastener 60 travels through the first elongated slot 24, slot 22 on the sliding guardrail panel as it is pushed forward by the impacting vehicle during an impact event. The longitudinally spaced tabs 26 formed of the material separating the slots 22, first elongated slot 24 are broken or sheared by the fastener 60 during an impact event, wherein the fastener secured to the rail of the downstream compartment remains stationary until each compartment is sequentially telescoped ( Figure 6 and Figure 10 ) until the tabs 26 break. The breaking of the tabs 26 absorbs energy and, therefore, applies a force to slow the movement of the guardrail or track section. The tabs 26 are sized so that the force required to break them is appropriate for the vehicle that has struck the crash bumper. Closely spaced tabs 26 produce a higher average force, while widely spaced tabs produce a lower average force. Many other parameters also influence the force generated by the tabs 26, such as the thickness, length, and width of the tabs 26, and whether more than one tab is cut at a time. In a preferred embodiment, the length L2 of the tabs 26 and the starting tab 28 is 0.43 inches and the width w1 is 0.75 inches. The tab thickness is 0.135 inches, which corresponds to the thickness of the guardrail panel or track section. Other tab sizes may be suitable. On one or more guardrail panels or one or more track sections at the front of the system (e.g., first bay 70), the tabs 26 are spaced 8.6 inches apart, while on guardrail panels at the rear (e.g., second bay 72, third bay 74, fourth bay 76, fifth bay 78), the tabs 26 are spaced 4.1 inches apart. In one embodiment, only one tab is cut from each panel at a time. This is accomplished by staggering the rows of vertically spaced tabs in each track in the longitudinal direction, as shown in FIG. Figure 2 、 Figure 6 and Figure 7 As shown in .

[0044] As disclosed above, each sliding guardrail panel or track segment 20 is clamped to the underlying stationary guardrail panel by fasteners 60. The fasteners 60 apply a predetermined compressive force between the panels. Consequently, the overlapping sliding guardrails or first and second track segments experience sliding resistance due to clamping friction. The clamping force applied by the fasteners 60 (e.g., bolts) is controlled by torqueing the bolts to a predetermined value. For example, in a typical crash cushion, the torque may be 33 foot-pounds. Higher or lower values ​​may also be used, for example, values ​​in the range of 25 foot-pounds to 130 foot-pounds. The torque applied to the bolts in each compartment (either the rear end or the downstream end of the compartment) can be the same, but in some cases, the torque may differ between compartments. For example, the fasteners at the downstream end of a compartment may have a higher torque than the fasteners at the upstream end of the compartment to ensure that the upstream compartment telescopes first and telescopes sequentially thereafter. The impacted sliding guardrail or track section 20 is attached to a spacer 94 which in turn is attached to the split support column assembly ( Figure 8 and Figure 12 ).

[0045] In operation, the crash cushion 10 is struck axially by the vehicle 12 in the longitudinal direction 2 and moves in the direction of travel of the vehicle. The impact head 18 is directly attached to the mounting bracket 90 ( Figure 9 ), the mounting bracket 90 is attached directly to the track section 20 or panel ( Figure 1 and Figure 9 ). The mounting bracket 90 and the first compartment panel or first track segment are attached to a spacer 94, which is coupled to a first pair of support post assemblies 120, which are connected to the mounting bracket 90 and the impact head 18. The spacer 94 is connected to the first pair of split support posts 100 by shear bolts 96. The first compartment panel or first track segment slides over the second compartment panel or second track segment as the first support posts are crushed during an impact.

[0046] The "first" track section or panel of the first compartment 70 is attached to the "second" track section or panel of the second compartment 72 by fasteners 60, which are tightened to a predetermined torque as described above. The amount of friction and corresponding energy dissipation that prevents the first compartment track section from sliding on the second compartment track section is primarily determined by the clamping torque of the fasteners 60.

[0047] The split support column 100 is welded to a ground anchor 150 configured as a mounting plate 152 that is bolted to the ground, for example, at a front portion of the mounting plate 152 by a fastening bolt 154, and holds the guardrail or track section ( Figure 8 and Figure 9 A pair of laterally spaced support posts 100 are connected by a laterally extending span or central web 130, wherein the support posts 100 and web 130 define a diaphragm 132. It should be understood that the term "detachment" refers to the release of the support posts 100 from the track segment 20, but the support posts preferably remain attached to the ground anchors 150, although in some embodiments the support posts may be released from the ground anchors 150. The ground anchors 150 may alternatively include lower posts or spikes buried in the ground.

[0048] As the panels or track sections of the first bay 70 begin to slide past the track sections of the second bay 72, the first pair of support posts 100 rotate, thereby shearing the shear bolts 96 attaching the support posts to the spacers 94. The cross member 99 remains connected to the upper spacers 94. In one embodiment, the support posts 100 are welded to the mounting plate 152 ( Figure 13A 、 Figure 13B 、 Figure 16A and Figure 16B ). The support column includes a front portion 104, a rear portion 106, and opposing side portions 108, wherein a rear weld 110 along the rear portion of the column holds the column to the base. Although shown as having a rectangular cross-section, it should be understood that the support column can have a non-rectangular cross-section, such as a circular cross-section, or a C-shaped or H-shaped cross-section, all of which can have a front, side, and rear portion. When the split support column is collapsed, the front weld 112 at the front of the support column and the side welds 114 at the sides break ( Figure 13A 、 Figure 13B as well as Figure 16A 、 Figure 16B ) or pull apart. Vertical slots 116 are added to the rear or back of each support column so that the central material or flange 118 of the support column defined between the vertical slots 116 forms a living hinge and minimizes stress on the rear weld 110 along the rear, while also minimizing the possibility of the side welds pulling apart and being transmitted to the rear. The bending stress is distributed over a large area of ​​the column material to reduce the chance of fracture of the rear weld 110 material ( Figure 13B and Figure 16B ). Vertical slots 116 are added near the edge of each column so that the weld along the bend area at the rear will not continue to break as the side welds 114 break. Likewise, vertical slots 116 can be added to the support columns at the front to provide a discontinuous, breakable weld.

[0049] During an impact event, e.g. Figure 18 As shown in FIG, the diaphragm 132 and support columns 100 are collapsed, which in one embodiment is defined as the angle at which the diaphragm no longer absorbs any significant amount of energy. For example, in one embodiment, the diaphragm 132 collapses once the diaphragm 132 has tilted beyond approximately 73 degrees, where the force applied by the diaphragm or a pair of support columns 100 that at least partially constitute the diaphragm is significantly reduced at this point, as shown in FIG. Figure 17 . To accommodate the force dissipation / energy dissipation during the collapse of the diaphragm, it may be desirable to limit the shearing of the tabs 26. In one particular configuration, the minimum length L1 of the first elongated slot is greater than or equal to at least 75% of the first distance traveled by the first track during the collapse of the diaphragm. In one embodiment, the minimum length L1 of the first elongated slot is greater than or equal to the first distance traveled by the first track during the collapse of the diaphragm and support column. In these systems, to accommodate the force dissipation / energy dissipation due to the collapse of the support column, it is preferred that no tabs 26 break over the travel distance, as shown in FIG. Figure 17 In one embodiment shown in FIG, the travel distance is about 0.33 meters. Figure 18 As shown in , when the panel or track segment has traveled or moved a travel distance of 0.33m, the support column tilts 73°. In other embodiments, the travel distance or float can be greater than 0.33m, for example 0.41m. Additional float or travel distance exceeding 0.33m can be provided on the track segment 20 of the first compartment 70 to further reduce ΔV (the difference between passenger and vehicle speeds). The panels or track segments 20 in the second compartment 72, the third compartment 74, and the fourth compartment 76 each have a float or travel distance of approximately 0.35m. The panels in the fifth or last compartment 78 can have a reduced travel distance or float (e.g., 0.28m) because the fifth compartment 78 will only compress when a heavier vehicle impacts the system. The larger force will not provide much deceleration on the heavier vehicle.

[0050] Reference Figure 18 , minimum float pass or through Calculate, where Figure 18 Define X, Z and In one embodiment, It is estimated to be about 73°, which is consistent with the partition or support column being overwhelmed, i.e. Figure 17 The energy dissipation shown in the figure corresponds to the energy dissipation achieved. The length of the float or travel distance can vary depending on the force required to push the diaphragm and the geometry of the system. The maximum float or travel distance will be achieved through a tipping angle of up to 89°. and very long columns and Z values ​​slightly larger than the thickness of the partition or column.

[0051] The fasteners 60 that clamp the first track section or panel to the second track section or panel pass through the first elongated slots 24 in the first track section. Between the slots are tabs 26 that break to absorb energy and slow the impacting vehicle. To prevent excessive force when the split post tips over, the panels or track sections of the first compartment 70 are designed so that none of the tabs 26 will break if the support post tips over. When the spacers attached to the stationary second set of support posts / spacers are struck by the spacers of the moving compartment, the track sections of the second compartment 72 move with the impacting vehicle and repeat the same behavior as the first compartment 70 ( Figure 11A and Figure 11B ). The behavior of the second compartment 72 sliding over the third compartment 74 and subsequent compartments follows the same mechanism.

[0052] It should be noted that the support posts 100 are connected to the spacers 94 by small shear bolts 96. The spacers are connected to the track sections by fasteners 60, and wherein the upper, laterally spaced pairs of spacers 94 are connected to the cross members 99. The small shear bolts 96 connecting the support posts 100 to the spacers 94 break shortly after the head impacts the support posts 100 and contribute little to the resistance to the post's collapse and / or any associated energy dissipation.

[0053] A plurality of (two shown) vertically spaced slots 142 are also provided in the downstream end portion 52 of one or more of the track segments 20 in the fourth and fifth compartments to prevent the deforming members 30 or shaped fins on the upstream end portion 50 of the track segment 20 or on the short panels 75 in the fourth and fifth compartments 76, 78 from engaging the upstream track segment until after the corresponding one or more support columns are collapsed. The vertically spaced slots 142 can be formed in the valley of the track segment. In one particular configuration, the minimum length of the vertically spaced slots 142 is greater than or equal to at least 75% of the first travel distance of the track segment during the collapse of the partition. In one embodiment, the minimum length of the one or more vertically spaced slots 142 is greater than or equal to the first travel distance of the track segment during the collapse of the partition.

[0054] The panels in the fourth compartment 76 and the short panel 75 attached to the spare 14 are configured with deforming members 30. As the sliding track segments from the fourth and fifth compartments 76 and 78 slide over the immediately rearward, non-sliding track segments, the sliding track segments are deformed by the deforming members. Consequently, an impacting vehicle may experience the force / energy dissipation of shear tabs 26, the force / energy dissipation from friction of the track segments 20 or panels sliding relative to each other, the force of deforming the track segments or panels through the deforming members 30, and the force of the bulkhead being crushed due to weld fracture and living hinge bending. If experienced simultaneously, the sum of all these forces, and the energy dissipated by these components, may be higher than would be expected from an impacting vehicle. The sum of the forces and energy dissipation can be reduced by modifying the system so that no portion of the track segments is sheared or deformed by the deforming members when the support posts are crushed. For example, one or more first elongated slots 24 and vertically spaced slots 142 can be elongated, as described above, so that the deforming member 30 does not engage the outboard sliding panel until the first travel distance has been reached. In this way, as the outboard track segment slides past the inboard track segment, no initial deformation occurs when the bulkhead separates or is knocked over / overturned. The length of the slot is determined by analyzing when the bulkhead support posts connected to the spacer on the impact side of the sliding panel collapse. Once one or more support posts collapse, the sliding track segment or panel can be engaged by the deforming member on the downstream track segment.

[0055] The total amount of force or energy dissipation can also be reduced by modifying the spacing of the tabs in the guardrail panel so that the starting tabs 28, 26 are not sheared until the post is almost collapsed. Figure 6 As shown in FIG, the first elongated slot 24 is overlong so that the first tab is not sheared until the post falls.

[0056] Another feature of the crash cushion is that each of the guardrail panels or track segments can be constructed with a start tab 28 located in the first elongated slots 24 that holds the downstream panel in place during telescoping of the system. These start tabs 28 increase the force required to initially move any downstream panel, thereby ensuring that the upstream panel and compartment telescoping first. For example, the track segment in the first compartment 70 may not have any start tabs disposed in the four first elongated slots 24. The track segments in the second and third compartments may each have two start tabs 28, or have start tabs 28 located in two of the four first elongated slots 24. The track segment in the fourth compartment 76 may have three start tabs 28 in three of the four slots (see Figure 6 ), and the fifth compartment 78 may have four starting tabs 28, one starting tab 28 in each first elongated slot 24, as in Figure 7. In this manner, each downstream panel requires the same or slightly greater force to initiate movement than its adjacent upstream panel, thereby ensuring that the upstream panel telescopes before the downstream panel. It should be understood that the length L1 of the first elongated slot 24 is defined as the length from the location of the first upstream fastener 60 to the end of the first elongated slot 24, regardless of whether the slot includes a start tab.

[0057] like Figure 2 、 Figure 3 、 Figure 8 and Figure 12 As shown in FIG, a guardrail system may include a cable 200 extending along the length of the system. The cable is mounted to a ground anchor at the front of the system and then routed through a spacer connecting the guardrail panel to the post. At the back of the system, the cable is attached to the system back-up. The cable improves the system's ability to redirect a vehicle impacting the side of the system and also helps guide the system as it telescopes during an end-on impact. The cable may be pre-tensioned, for example by applying torque to a predetermined value to the threaded end of the cable.

[0058] Although the present invention has been described with reference to preferred embodiments, those skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the invention. Therefore, the foregoing detailed description is intended to be illustrative rather than restrictive, and the appended claims, including all equivalents thereof, are intended to define the scope of the invention.

Claims

1. A crash buffer comprising: a first track segment comprising an upstream end portion, a downstream end portion, and a first side portion; a second track segment comprising an upstream end portion, a downstream end portion, and a second side portion facing the first side portion of the first track segment, wherein the upstream end portion of the second track segment overlaps the downstream end portion of the first track segment and is secured to the downstream end portion of the first track segment by a fastener, and wherein the first track segment is movable relative to the second track segment from a pre-impact position to an impact position in response to an axial impact with the crash bumper; wherein the first track segment includes a plurality of longitudinally spaced slots aligned with and extending upstream of the fastener, wherein the plurality of slots includes a first elongated slot aligned with the fastener when the first track segment is in the pre-impact position, wherein the first elongated slot has a first length; and A support post is releasably connected to the first track segment and is rotatable from an upright position to a collapsed position, wherein, during the axial impact, the support post is releasable from the first track segment and is rotatable to the collapsed position after the first track segment has moved a first travel distance, wherein the first length is greater than or equal to at least 75% of the first travel distance.

2. The crash buffer according to claim 1, wherein: The second track segment includes a deformable member secured to the upstream end portion of the second track segment, and wherein the first track segment has a second elongated slot aligned with the deformable member, wherein the second elongated slot has a second length greater than or equal to at least 75% of the first travel distance.

3. The crash buffer according to claim 1, wherein: The first track section includes a plurality of vertically spaced second elongated slots, and wherein the second track section includes a plurality of vertically spaced deformable members aligned with the vertically spaced second elongated slots.

4. The crash buffer according to claim 3, wherein: The plurality of vertically spaced second elongated slots includes two vertically spaced second elongated slots, and wherein the plurality of vertically spaced deformable members includes two vertically spaced deformable members.

5. The crash buffer of claim 1, wherein: The first track segment includes a plurality of vertically spaced rows of the plurality of slots spaced longitudinally apart, wherein each of the plurality of rows of slots includes the first elongated slots, and further includes a plurality of vertically spaced fasteners that align with the first elongated slots of the vertically spaced rows and secure the first track segment and the second track segment.

6. The crash buffer of claim 5, wherein: The plurality of vertically spaced apart rows comprises four rows.

7. The crash buffer of claim 5, wherein: At least one of the first elongated slots includes a start tab extending across the first elongated slot, wherein the at least one first elongated slot is shorter than at least another first elongated slot of the first elongated slots.

8. The crash buffer of claim 1, wherein: The support post is releasably coupled to a spacer via a shear fastener, wherein the spacer is coupled to the second track segment.

9. The crash cushion of claim 1 further comprising a ground anchor coupled to the support column, wherein The support column has a front portion, a rear portion, and opposite side portions, wherein the rear portion includes a pair of vertical slots and a hinge portion defined between the slots, wherein a bottom portion of the hinge portion and at least one of the front portion and the side portion are connected to the ground anchor by a weld, wherein the weld connecting the front portion and at least one of the side portions is capable of breaking when the support column is capable of rotating about the hinge portion from the upright position to the collapsed position.

10. The crash buffer of claim 9, wherein: The support column has a rectangular cross-section.

11. The crash buffer of claim 10, wherein: The front portion includes a second pair of vertical grooves and a fused portion defined between the second pair of grooves, wherein one of the welds connects a bottom portion of the fused portion to the ground anchor.

12. The crash buffer of claim 9, wherein: The ground anchor includes an anchor plate.

13. The crash cushion of claim 1 comprising a pair of laterally spaced first rail segments, a pair of laterally spaced second rail segments secured to the first rail segments, and a pair of laterally spaced support posts releasably coupled to the first rail segments.

14. The crash buffer of claim 13, wherein: The pair of laterally spaced support columns are connected to define a bulkhead.

15. The crash cushion of claim 1 further comprising a ground anchor coupled to the support column, wherein The support post remains coupled to the ground anchor after the support post is released from the first track segment and rotated to the downed position.

16. A crash buffer comprising: a first track segment comprising an upstream end portion, a downstream end portion, and a first side portion; a second track segment comprising an upstream end portion, a downstream end portion, and a second side portion, wherein the upstream end portion of the second track segment overlaps the downstream end portion of the first track segment and is secured to the downstream end portion of the first track segment by a fastener, wherein the first side portion and the second side portion face each other, and wherein the first track segment is movable relative to the second track segment from a pre-impact position to an impact position in response to an axial impact on the crash bumper; a support post releasably connected to the first track segment and capable of rotating from an upright position to a collapsed position when the first track segment moves from the pre-impact position to the impact position, wherein the support post absorbs a first amount of energy when the support post is released from the first track segment and rotated to the collapsed position; and wherein the first track segment includes a plurality of longitudinally spaced slots aligned with and extending upstream of the fastener, wherein a first pair of adjacent slots are separated by a tab, and wherein the fastener engages the tab and absorbs a second amount of energy after the support post absorbs at least 75% of the first amount of energy.

17. The crash buffer of claim 16, wherein: The second track segment includes a deforming member fixed to the upstream end portion of the second track segment, and wherein the first track segment has a second elongated slot aligned with the deforming member, wherein the deforming member is capable of engaging with the first track segment at an end of the second elongated slot and absorbing a third amount of energy after the support column absorbs at least 75% of the first amount of energy.

18. The crash buffer of claim 16, wherein: The first track section includes a plurality of vertically spaced second elongated slots, and wherein the second track section includes a plurality of vertically spaced deformable members aligned with the vertically spaced second elongated slots.

19. The crash buffer of claim 18, wherein: The plurality of vertically spaced second elongated slots includes two vertically spaced second elongated slots, and wherein the plurality of vertically spaced deformable members includes two vertically spaced deformable members.

20. The crash buffer of claim 16, wherein: The first track segment includes a plurality of vertically spaced rows of the plurality of slots spaced longitudinally apart, wherein each of the plurality of rows of slots includes a first elongated slot, and further includes a plurality of vertically spaced fasteners that align with the first elongated slots of the vertically spaced rows and secure the first track segment and the second track segment.

21. The crash buffer of claim 20, wherein: The plurality of vertically spaced apart rows comprises four rows.

22. The crash buffer of claim 20, wherein: At least one of the first elongated slots includes a start tab extending across the first elongated slot, wherein the at least one first elongated slot is shorter than at least another first elongated slot of the first elongated slots.

23. The crash buffer of claim 16, wherein: The support post is releasably coupled to a spacer via a shear fastener, wherein the spacer is coupled to the second track segment.

24. The crash cushion of claim 16, further comprising a ground anchor coupled to the support column, wherein The support column has a front portion, a rear portion, and opposite side portions, wherein the rear portion includes a pair of vertical slots and a hinge portion defined between the slots, wherein a bottom portion of the hinge portion and at least one of the front portion and the side portion are connected to the ground anchor by a weld, wherein the weld connecting the front portion and at least one of the side portions is capable of breaking when the support column is capable of rotating about the hinge portion from the upright position to the collapsed position.

25. The crash buffer of claim 24, wherein: The support column has a rectangular cross-section.

26. The crash buffer of claim 24, wherein: The front portion includes a second pair of vertical grooves and a fused portion defined between the second pair of grooves, wherein one of the welds connects a bottom portion of the fused portion to the ground anchor.

27. The crash buffer of claim 24, wherein: The ground anchor includes an anchor plate.

28. The crash cushion of claim 16 comprising a pair of laterally spaced first rail segments, a pair of laterally spaced second rail segments secured to the first rail segments, and a pair of laterally spaced support posts releasably coupled to the first rail segments.

29. The crash buffer of claim 28, wherein: The pair of laterally spaced support posts are connected.

30. The crash cushion of claim 16, further comprising a ground anchor coupled to the support column, wherein The support post remains coupled to the ground anchor after the support post is released from the first track segment and rotated to the downed position.

31. A support column assembly comprising: Ground anchor; as well as A support column having a front portion, a rear portion, and opposite side portions, wherein at least the rear portion includes a pair of vertical slots and a hinge portion defined between the slots, wherein a bottom portion of the hinge portion and at least one of the front portion and / or the side portions are connected to the ground anchor by a weld, wherein when the support column is subjected to an impact, the weld connecting the front portion and / or at least one of the opposite side portions is configured to break when the support column is rotated about the hinge portion from an upright position toward the ground anchor to a collapsed position.

32. The support column assembly of claim 31 , wherein: The support column has a rectangular cross-section.

33. The support column assembly of claim 31 , wherein: The front portion includes a second pair of vertical grooves and a fused portion defined between the second pair of grooves, wherein one of the welds connects a bottom portion of the fused portion to the ground anchor.

34. The support column assembly of claim 31 , wherein: The ground anchor includes an anchor plate.

35. A method of absorbing energy of a vehicle using a crash buffer, the method comprising: Providing a support column assembly according to claim 31; the head of the impactor striking the crash buffer; sliding a first track segment from a pre-impact position to an impact position relative to a stationary second track segment, wherein the first track segment and the second track segment are coupled by a fastener; sliding the fastener in a slot defined in the first track segment, wherein the slot has a first length; and During the impact of the impact head, a support post connected to the first track segment is rotated from an upright position to a collapsed position after the first track segment has moved a first travel distance, wherein the first length is greater than or equal to at least 75% of the first travel distance.

36. The method according to claim 35, wherein The second track segment includes a deformable member secured to the second track segment, and wherein the first track segment has a second elongated slot aligned with the deformable member, wherein the second elongated slot has a second length greater than or equal to at least 75% of the first travel distance.

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