Patent Application
20200248418
This invention relates to crash cushion apparatus employed to absorb energy from a vehicle crash. More particularly, the crash cushion apparatus of this invention is a water based crash cushion system non-anchored along the length thereof attached at its rear end to a rigid hazard object.
Water based non-anchored crash cushions are known in the art and they operate primarily by momentum transfer (the impact of the impacting vehicle is transferred to the expelled water when the modules fracture and the water is dispersed at high velocity).
In these prior art arrangements a portion of the energy of the impacting vehicle is transferred through compressive forces applied from collapsing the structural elements and a small amount from pressure building up in the water containers. Utilizing the principles of the present invention, as compared to the known prior art, the compression is significant during the later phase of the impact where the rate of compression is less, a much larger portion of the energy being absorbed by the compressive forces prior to the plastic containers fracturing during the mid to late period of the impact event. This is accomplished by using plastic formulations that are less frangible and thus hold together longer to allow the pressure to build up more during the compression phase than the other cushions in this category.
The following documents are believed to be representative of the state of the prior art in this field: U.S. Pat. No. 7,351,002, issued Apr. 1, 2008, U.S. Pat. No. 6,666,616, issued Dec. 23, 2003, U.S. Pat. No. 8,864,108, issued Oct. 21, 2014, U.S. Pat. No. 8,783,999, issued Jul. 22, 2014, U.S. Pat. No. 7,708,492, issued May 4, 2010, U.S. Pat. No. 7,144,188, issued Dec. 5, 2006, U.S. Pat. No. 7,070,031, issued Jul. 4, 2006, U.S. Pat. No. 6,913,415, issued Jul. 5, 2005, U.S. Pat. No. 6,413,009, issued Jul. 2, 2002, U.S. Pat. No. 5,988,934, issued Nov. 23, 1999, U.S. Pat. No. 5,531,540, issued Jul. 2, 1996, U.S. Pat. No. 6,179,516, issued Jan. 30, 2001, U.S. Pat. No. 6,669,402, issued Dec. 30, 2003, U.S. Pat. No. 7,618,212, issued Nov. 17, 2009, U.S. Pat. No. 6,082,926, issued Jul. 4, 2000, U.S. Pat. No. 6,848,857, issued Feb. 1, 2005, U.S. Pat. No. 7,303,353, issued Dec. 4, 2007, U.S. Patent App. Pub. No. US 2010/0111602, published May 6, 2010, U.S. Patent App. Pub. No. US 2007/0243015, published Oct. 18, 2007, U.S. Pat. No. 8,491,217, issued Jul. 23, 2013, U.S. Pat. No. 8,777,510, issued Jul. 15, 2014, U.S. Pat. No. 9,822,502, issued Nov. 21, 2017, U.S. Pat. No. 7,351,008, issued Apr. 1, 2008, U.S. Pat. No. 6,474,904, issued Nov. 5, 2002, U.S. Patent App. Pub. No. US 2002/0025221, published Feb. 28, 2002, U.S. Design Pat. No. D596,062, issued Jul. 14, 2009, U.S. Patent App. Pub. No. US 2009/0060650, published Mar. 5, 2009 and U.S. Pat. No. 6,059,487, issued May 9, 2000.
The anchorless crash cushion apparatus of the present invention includes a plurality of interconnected water-filled crash cushion elements and a forward element.
Vehicle capture structure is operatively associated with the forward element and operable to capture a vehicle frontally impacting the forward element, resist upward tilting of the impacting vehicle and substantially prevent ramping of the impacting vehicle over the forward element and following elements.
Stabilizing structure including a midnose structure is operatively associated with the plurality of interconnected crash cushion elements to resist relative rotation therebetween in both vertical and lateral planes during vehicle impact.
A metal nose cap is located in front of the forward element and is cooperable with the forward element to capture a frontal impacting vehicle and reduce downward pitch of smaller vehicles with lower centers of gravity and also assist with capture of the vehicle bumper.
Other features, advantages and objects of the present invention will become apparent with reference to the following description and accompanying drawings.
Referring now to the drawings, anchorless crash cushion apparatus constructed in accordance with the present invention includes a plurality of plastic crash cushion elements or modules of identical construction, including an empty forward element 10 and water-filled elements 12, one of the water-filled elements 12 located adjacent to and immediately behind forward element 10.
Each of the crash cushion elements or modules is hollow and has an element front 14, an element back 16, an element bottom 18, an element top 20 and element sides 22, 24.
The element sides 22, 24 of the plurality of interconnected crash cushion elements each form a pair of elongated cavities 26 spaced from one another and extending along the sides, the elongated cavities 26 of the elements being in substantial alignment.
Stabilizing structure in the form of straps 28 of steel or other suitable metal extending along the elongated cavities 26 are attached to the crash cushion elements.
Connector pins 30 extend between and through the element sides of the plurality of crash cushion elements and through overlapping ends of the metal straps extending from the elongated cavities of adjacent crash cushion elements.
The connector pins 30 are operable to pass through and connect together the metal straps 28 on both sides 22, 24 of the adjacent crash cushion elements. The connector pins 30 include spring clips 32 to selectively latch the connector pins to or unlatch the connector pins from the crash cushion elements.
Upper and lower metal straps are mounted at each element side and maintained under tension by the connector pins passing through the bodies of the connected elements. The elongated cavities 26 operate as tension strap valleys constraining the metal straps vertically and maintaining spacing between the tensioned upper and lower metal straps.
Spaced vertical buckling cavities 40 are formed in the element sides 22, 24, the buckling cavities at opposed element sides being alternately positioned and offset from one another. Initial impact by a vehicle compresses alternating buckling cavities at opposite element sides and operates to create a zig-zag compression and stabilize a column formed by the interconnected crash cushion elements. A zig-zag pattern is disclosed generally in U.S. Pat. No. 6,428,237, issued Aug. 6, 2002, but is substantially less in the apparatus of the present invention.
A top stiffness spine 42 is formed at the element top spaced from and positioned between the locations of the buckling cavities 40. Fill holes with plastic plugs 38 act as water filling ports and relieve excess water pressure during impact. The fill holes are raised and prevent liquid (usually rain water) that pools at the top surface of the element from draining into the element during storage. Reciprocal structures on the underside of the elements restrict horizontal movement when stacked.
Port defining passageway structures 44 extend between the element sides, the ports at the sides allowing fork lifts (not shown) to transport elements. Rigidity of the element is increased by rigidly connecting the otherwise unsupported long vertical element sides. Rounded corners eliminate stress concentrations during impact and provide more uniform thickness during rotomolding process.
The metal straps 28 are substantially unattached to the element sides 22, 24 between the connector pins 30. The straps buckle and bend outwardly away from the element sides when a compressive force collapses a crash cushion element to which the strap is attached by a connector pin. Bolts 29 may be employed to keep the straps from falling from the crash cushion element if connector pins are removed for maintenance or other purposes.
A metal nose cap 46 is located at the front 14 of the forward element 10. Metal tension straps along the forward element extend to the metal nose cap and are connected thereto. The front 14 defines a notch 48 behind the metal nose cap 46. The metal nose cap has a weakened midsection located in front of the notch. The metal nose cap and the forward element are cooperable to capture a frontal impacting vehicle and reduce downward pitch of smaller vehicles with low centers of gravity and also assist in the capture of the vehicle bumper.
The nose cap has a surface with visible delineation and provides extra reinforcement of the tension straps to the front of the forward element.
A metal midnose structure 50 engages the element back of the forward element 10 and the element front of the adjacent crash cushion element 12. The midnose structure is operable to contain and control debris from the forward element when collapsed by an impacting vehicle, operable upon subsequent engagement thereof by the vehicle to even the distributed compressive forces of the vehicle to downstream crash cushion elements, and operable to deter against backward tipping of the forward element.
The metal midnose structure is L-shaped and includes a vertical midnose member 52 extending upwardly from a horizontal midnose member 54.
The vertical midnose member 52 is positioned behind the forward element 10 and in front of the adjacent crash cushion element 12. The horizontal midnose member 54 is positioned under at least a portion of the forward element 10. Side panels 56 extend upwardly from the horizontal midnose 54 and are disposed over lower side portions of forward element 10.
The metal midnose structure 50 as well as the metal straps 28 help stabilize the tendency of the water-filled modules to skew (buckle) in the horizontal plane as well as the vertical plane. This significantly helps keeping the system from buckling during the compressive phase when the pressure is higher. With increasing pressure there is a natural tendency for the elements to zig-zag which relieves the longitudinal loading into the vehicle. By limiting zig-zag formation and keeping the elements in better alignment higher pressures are allowed to build up and keep the higher loading pointed along the longitudinal axis of the impacting vehicle, resulting in more efficient absorption of the vehicle impact energy, bringing the vehicle to a controlled stop in a shorter distance with acceptable occupant risk factors (g-levels, roll/pitch/yaw, etc).
The metal midnose structure 50 aids in reducing the vaulting tendency of the vehicle impacting the filled elements of the cushion. This is accomplished by increasing the resistance to a vertical rotation of the connection between the forward element and the adjacent element and reduces the overall upward pitching tendency. Without this structure the effect would result in the vehicle energy not being absorbed efficiently because as the vehicle vaults, the longitudinal force on the vehicle that slows it is redirected upward and outside of the center of pressure. Thus, the longitudinal force into the vehicle drops off quickly, the vehicle velocity is not significantly further reduced, and is not brought to a controlled stop by the cushion.
The forward element back 16 includes spaced rear connector projections 58 defining a connector recess 60 and a stabilizing member 62 between the connector projections. The vertical midnose member 52 includes a midnose connector protrusion 64 defining a notch 66 receiving the stabilizing member 62.
The midnose structure 50 includes an upper panel 68 located above the midnose connector protrusion 64, the upper panel is positioned over a portion of the forward element 10.
The midnose connector protrusion 64 defines a midnose connector recess 70 for receiving a connector protrusion extending from the adjacent crash cushion element 12.
The midnose structure 50 additionally includes side panels 74 extending upwardly from the horizontal midnose member 54 alongside lower portions of the forward element sides 22, 24.
The anchorless crash cushion apparatus of this invention incorporates an interlocking geometry feature resisting location of the vertical and lateral planes at the connection between elements. Interconnection structure is similar to the essentially tab like arrangement employed at the forward element and adjacent element with the connection with the midnose structure. Each of the elements has two tabs or projections extending outward at the sides from one end of the forward element 10 and also connector recess structure at the opposite end thereof corresponding to the connector structure cooperating therewith utilized in the metal midnose structure. These arrangements are essentially tabs which protrude from the ends of the elements 12 and mate with central tab structure of the adjoining element. Connector pins extending through holes across the elements lock the two elements to one another and such horizontal pin connection increases moment capacity to resist lateral rotation, essentially functioning as mating interlocking tabs.
A transition weldment 78 is incorporated in the anchorless crash cushion apparatus of this invention for attaching the apparatus to a rigid hazard object such as that indicated by reference numeral 80. The transition weldment provides additional crush for heavy vehicles that bottom out and increase collapse from impact of heavier vehicles with excessive impact velocity to provide a higher margin of safety for vehicle occupants.
The transition weldment includes a weldment housing 82 having side walls and a welded notched front plate 81 only welded at the top and bottom, allowing the side walls of the weldment housing to collapse when impacted from the front along the centerline of the apparatus.
Metal straps 28 are attached to the transition weldment and to an endmost crash cushion element 12 and connector pins 30 extend through the metal straps connecting the transition weldment and the endmost crash cushion element. The notch 83 of the front plate conforms to the shape of and receives the element back. The transition weldment includes upper and lower brackets 86, 88 securing the weldment housing to the rigid hazard object, the weldment housing otherwise not being welded to the rigid hazard object.
The weldment is rigid enough to not begin to crush as the system is compressing until the vehicle starts to interact with the end of the system. This latent crush adds some residual capacity to the system in the final milliseconds of the impact. The notch still provides some rigidity in angled impacts so as to reduce the pocketing into the system just before the rigid hazard object.
The forward element 10 will still fracture in the early stages of the impact due to the high rate of loading and the disposition of the mass of water will reduce the velocity of the impacting vehicle by the momentum transfer/impulse mechanism. However, as the velocity of the impacting vehicle is decreased, the rate of transfer is reduced to a point that momentum transfer becomes inefficient. Thus, with the improved compression characteristics in the later stages of the impact, the final energy absorption is accomplished by increased compression force during the displacement period prior to the last element finally fracturing and dispersing the water. This final water dispersion is at a very low velocity and inefficient (much of the water “leaks” out instead of being sprayed out).
As indicated above, the forward element is substantially empty (not filled with water). At high velocity, the rate of momentum transfer would cause excessive g levels for lighter weight vehicles. The stabilizing structures including the metal straps provide sufficient force to slow smaller vehicles so that the rate of momentum transfer as the rear view (water filled) elements are encountered acceptable g levels can be achieved and the total length of the crash cushion apparatus is optimized between the light and heavy vehicle.
