Embodiments of the present invention provide vehicle restraints and fence systems that offer better protection to the driver and vehicle in the event of an accident where the car becomes airborne and leaves the road or track.

CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 61/563,343, filed Nov. 23, 2011, titled “Vehicle Catch Fence,” the entire contents of which are hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Embodiments of the present invention relate generally to catch systems for vehicles leaving a road, highway, track, platform, or surface at an accelerated pace. For example, the catch systems and methods may be used on a racetrack to help prevent a car crash from becoming even more dangerous to the car driver, as well as to the spectators at the track. The catch system may be used to more safely decelerate the vehicle's motion than a hard wall, while also preventing the car from continuing on its course of travel into the stands or stadium. Additionally or alternatively, the catch systems and methods may be used on any motor sports facilities, motocross sidelines, motorcycle or car demonstrations, on circus sidelines, for boat or other water craft races or demonstrations, highways, or any other instance when fast moving or otherwise motorized vehicle may become a dangerous projectile. 
       BACKGROUND 
       [0003]    There is a need for racetrack compliant fences. Fatal crashes, particularly for Indy car drivers, have brought this need to the forefront in recent years. Currently, race track walls are manufactured of cement, which does not cushion or absorb any kinetic energy of a moving object. The fences and fence posts that rise above track walls are similarly inflexible. Accordingly, the present inventors have sought to develop an energy absorbing fence. 
         [0004]    Energy-absorbing barriers have been used in connection with airport runways, and these barriers are designed to stop an aircraft that is overrunning a runway, but to do so in a manner that safely halts the vehicle's movement while not injuring passengers and personnel. Examples of aircraft and other vehicle halting systems are described in many of the assignee's patents and patent applications, including U.S. Pat. Nos. 6,726,400; 6,971,817; 7,261,490; 7,467,909; 7,597,502; 7,837,409; 8,007,198; 8,021,074; 8,021,075; 8,224,507 and U.S. Patent Publication Nos,  200810014019 ;  2011 / 0020062 ; and  2011 / 0177933 . For example, in addition to systems designed to stop overrun aircraft, other energy-absorbing walls have been considered for use in highway situations as well, in order to stop a car from leaving the highway at a dangerous pace, but to also stop the car without injuring its occupants. Further improvements to catch fnces, however, are needed, particularly for high speed crashes, such as those occurring at speedways or racetracks. 
       BRIEF SUMMARY 
       [0005]    Embodiments of the invention described herein thus provide vehicle catch fence systems and methods to be used at motorsports facilities and other venues where vehicle projectile safety is concerned. They are generally intended, to be used in place of rigid fencing that is widely installed to contain airborne race cars or other vehicles and keep them from leaving, the racetrack and endangering spectators behind the fences. Current fences are a hazard to drivers because of their rigidity and tendency to cause severe damage to the car if strikes the fencing material. 
         [0006]    Some of the embodiments described herein move the rigid poles and other unforgiving materials back from the outer edges of the race track and provide some cushioning and catching effect before the car encounters any fixed objects. The catch systems may be designed at various angles, they may be installed in multiple sections, they may be designed to catch and cushion multiple cars or vehicles, and may have various other features described below. The general intent was to develop a compliant fence system that offers better protection to the driver and the car in the event of an accident where the car becomes airborne and leaves the track. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  shows a schematic of a first catch fence embodiment. 
           [0008]      FIGS. 2-4  illustrate a C-fence catch fence embodiment. 
           [0009]      FIGS. 5-9  illustrate a leaf spring catch fence embodiment. 
           [0010]      FIGS. 10-11  illustrate an alternate catch net embodiment. 
           [0011]      FIGS. 12-13  illustrate an alternate cable mount. 
           [0012]      FIG. 14  illustrates a pillow spring mounting concept. 
           [0013]      FIG. 15  illustrates a hydraulically counteracted pivoting pole system. 
           [0014]      FIG. 16  illustrates an attachment of the net/fence to a SAFER barrier. 
           [0015]      FIG. 17  illustrates a large textile brake concept. 
           [0016]      FIG. 18  illustrates a pivoting top pole section with a leaf spring energy absorber. 
           [0017]      FIG. 19  illustrates a large, collapsible airbag. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Embodiments of the present invention provide various embodiments for catch fence systems and methods. Although the embodiments described, herein may be used in various venues, they are described in connection with a race track for ease of explanation. However, it should be understood that the catch systems and methods described herein may be useful in any other circumstance when a motorized vehicle, is to be stopped safely and effectively, 
         [0019]    In one embodiment, the fence poles are moved back from the edge of the race track, and they support a catch net and energy absorbers to absorb the energy of cars that have left the racetrack and become airborne. An example of such a system is shown in  FIG. 1 . This fence is designed to be engaged at an oblique angle. It can engage multiple cars, which is necessary, as cars are typically made airborne from multiple car contacts in a single crash. The fence is designed to be installed in sections that are temporarily connected to each other (side by side) so that one section engaged will absorb energy while an adjacent section (or sections) remains in place and ready to catch other cars. 
         [0020]    In the embodiment shown in  FIG. 1 , the net sections are divided by break-away C-clips that allow one section to detach from its neighbor section so that only the section that is needed is utilized. The fence also uses pivoting pulleys with a friction brake system mounted on the ground. The friction braking on the back pulleys particularly allows for softening the impact and can let out cable as needed. The top pulleys may rotate to guide the cable where it is needed most. Secured by the pulleys is a catch netting. In the figure shown, the netting is designed as nylon netting with nylon straps, but it should be understood that any appropriate net material may be used, as long as it contains sufficient strength properties. It is shown that the net may be 30-40 feet high, but it should be understood that lower fences may be more realistic in practice, and as such, the fence may be up to 20 feet instead. A secondary safety steel mesh catch fence is provided as a back-up barrier to prevent debris from entering the spectator seating areas. The system is designed for high speed, short run outs, as compared to traditional road barriers that are designed for lower speeds and longer run outs. It is desirable that repair to a utilized fence section can be conducted quickly e.g., in approximately 20 to 30 minutes and possibly less), to allow a race to continue after a catching incident. 
         [0021]    In improving upon this fence design, further considerations were to construct a simpler fence, which could render it easier to accept by the industry, as well as easier to install at a particular venue. Additionally, although safety is of particular concern, it is also desirable to not limit spectator sight lines, where possible. The space availability between the existing track wall and the grandstands is also different at every track, so it is desirable that the catch solution be modular and adjustable. Further, rapid system reset after an accident is an additional important consideration. Although not wishing to be bound to the following data, the following table provides the estimated magnitude of the forces involved in typical racetrack crashes and indicates the power that the catch systems are designed to contain. (Note that these are energies involved with straight-line impacts, and could be considered worst-case scenarios.) The magnitudes of force to be contained and thus designed around are shown below. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Racetrack Crash Force Data 
               
             
          
           
               
                   
                   
                 Approximate 
                   
                   
                   
                 Max 
               
               
                   
                 Vehicle 
                 Crash Speed 
                 Run- 
                 Kinetic 
                   
                 Decel- 
               
               
                   
                 Weight 
                 to Consider 
                 out 
                 Energy 
                 Force 
                 eration 
               
               
                 Car Type 
                 (lbs) 
                 (mph) 
                 (ft) 
                 (ft-lbf) 
                 (lbf) 
                 (g's) 
               
               
                   
               
             
          
           
               
                 NASCAR 
                 3,400 
                 120 
                 25 
                 1,636,692 
                 64,468 
                 19.3 
               
               
                 IRL 
                 1,800 
                 180 
                 25 
                 1,949,589 
                 77,984 
                 43.3 
               
               
                 Sprint 
                 900 
                 90 
                 20 
                 243,699 
                 12,185 
                 13.5 
               
               
                   
               
             
          
         
       
     
         [0022]    C-fence. 
         [0023]    A further embodiment of a catch fence system and method is referred to as the C-fence, and is shown in  FIGS. 2-4 . The C-fence concept involves “C” shaped poles that connect at their bottom to the back of the existing racetrack wall at a pivot joint. The tops of the poles are free to pivot away from the track during an impact. Each pole is connected to a large torsion spring or hydraulic cylinder at the bottom joint to dissipate energy. The main cables are suspended between the poles on vertical cables that run between the top and bottom of each “C” pole. The smaller mesh debris fencing may be installed along the back side of the “C” frame, or it could be integrated with the main cables out at the “C” opening. 
         [0024]    Advantages of the C-fence include that the concrete wall at tracks is a consistent feature to build off of so it is a stable solution. The C-fence also does not take up valuable real estate, and it is considered to have a potentially simple, inexpensive construction. It can also be installed without major construction changes to the facility, and it eliminates poles from impact area. 
         [0025]    Leaf-spring. A further embodiment is the Leaf Spring fence, shown in  FIGS. 5-9 . The Leaf Spring concept involves a simple way to “re-mount” and suspend the main safety cables of a fencing system off of the existing support poles. Without wishing to be bound by any theory, it is believed that by moving the support cables of the poles by some distance, more clearance can be created in front of the poles in situations where the driver's side of the car contacts the catch fence. A “U” shaped bracket it could be square or round, depending on the pole style in use) is mounted to the existing upright, and it is used in turn to mount a leaf spring assembly. The leaf spring assembly contains the cable via a sliding connection at its end, so that in the event of a crash, the leaf spring would flex while riding along the length of the cable. The main safety cables would be spaced via a simple “U” shaped bracket that also ties the ends of the leaf springs together. The leaf springs could be fabricated straight and be mounted to the pole at an angle, or they could be fabricated “5” shaped and be mounted parallel to the track wall as shown in  FIG. 5 .  FIG. 6  illustrates a side view of the leaf spring concept.  FIGS. 7-9  illustrate further views of the leaf spring concept and show details of the leaf spring connection to the pole. 
         [0026]    Potential advantages of the leaf spring concept are that is provides a relatively simple and elegant design, it is retrofittable, it can be implemented with a low cost, it can be designed to be self-resetting, it requires minimal changes to existing infrastructure such that it can work with existing fencing components. 
         [0027]    Catch Net. 
         [0028]    A further embodiment provides a catch net modification to the first embodiment shown above, but that provides to larger, less segmented system that addresses some of the issues identified with the first embodiment (such as net complexity, determining what happens between the net sections, post integrity, and runout distance issues). Examples of the catch net are shown in  FIGS. 10-11 . Instead of a segmented net that would require joints between sections, the Catch Net embodiment is installed along the entire length of a racetrack curve, as shown in  FIG. 10 . The main horizontal safety cables are supported by vertical cables at each curved pole. Once the cables extend past the covered safety area, they are routed together and are terminated at each end to an energy absorber. The vertical cables are rigidly anchored at the bottom to the back of the track safety wall, and are routed through a pulley at the top, then to an energy absorber located at the base of the pole. A smaller mesh debris fence may be integrated into the horizontal and vertical cables, or it may be mounted along the curved support posts at the back. 
         [0029]    During a crash event, the Catch Net system would flex and act like a web, deforming the most at the impact site. The energy absorbers at each end of the main horizontal cables may be textile brakes, allowing for easy replacement in the event of a crash, although any appropriate form of energy absorber may be used. For example, the energy absorbers on the vertical cables may be smaller textile brakes or TZC units, depending on the energy absorber capacity required. In either case, replacement of the vertical energy absorbers may be made easy as well. Moreover, there may be enough flex in the main horizontal cables that an energy absorber may not be required at each end, if at all. 
         [0030]    Some benefits of this Catch Net design are that it provides a relatively simple construction. There are not as many cables, pulleys and connection points as provided by the initial first embodiment. This solution also leverages a core competency of the developers by use of textile brakes or TZC (transition zone control) units. The cable system acts like a web, flexing most near impacts, but the system is also “active” at multiple points along the curve so that impacts from multiple cars could be absorbed. There are not any “Mechanisms” or additional units required. The Catch Net deign also allows for built-in variability for different tracks and car sizes. The system could be mounted to the back of the SAFER barrier, or to the concrete retaining wall, or to both. (It should be understood that in an alternate embodiment, the system need not be mounted to the SAFER barrier, which could minimize the wall to pole distance.) (“SAFER” stands for Steel and Foam Energy Reduction, and such walls are installed along curves of automobile race tracks and are intended to absorb and reduce kinetic energy during the impact of an accident, and thus, lessen injuries sustained to drivers.) The net is also easy to reset between events—replacement of energy absorber packs or TZC units is all that is required, plus mesh repair, if needed. 
         [0031]    In an alternate modification, it may be possible that only the bottom four or five horizontal cables are attached to an energy absorber. Additionally, the horizontal cable stretch may possibly be used as the energy absorber. It is also possible to adapt this solution so that it can also be installed on a straight section of track, as well if desired. 
         [0032]    Alternate Cable Mount. 
         [0033]    A fifth embodiment is an alternate cable mount. The alternate cable mount concept is an alternate method of connecting and aligning the horizontal safety cables of the system. It provides a method of spacing and holding the horizontal cables that provides more clearance space between each cable and the mounting point. One benefit of this design is that the cable can be held away from its mounting structure somewhat, allowing space between cables for a ear or driver to pass through in the event of an accident, 
         [0034]    As shown in  FIG. 13 , an angled pole secures a series of rolled or formed plates or springs that are bolted together to act as cable spacer, while bolted to a ground or wall anchor at the bottom. The purpose of the springs is to support the main horizontal cables and to provide clearance between them in the event of a car striking the fence. The cables provided between the angled pole and springs further prevent someone from standing between the springs and the pole. 
         [0035]    Pillow Spring Mounting Concept. 
         [0036]    A further alternate the above alternate cable mount is the pillow spring mounting concept. The spring mounting concept provides a compliant mount for the cable held a distance away from the support post. An example is shown in  FIG. 14 . The figure shows that a rolled plate may be used as a pillow spring. A U-bolt on the outside of the spring provides a cable guide. One of the benefits of this design is the reduction of the impact area between horizontal members. 
         [0037]    Hydraulically Counteracted Pivoting Pole System. 
         [0038]    A further embodiment is the Hydraulically Counteracted Pivoting Pole System, shown in  FIG. 15 . This is a concept that involves using the poles to absorb the energy of a car leaving the track. The poles are mounted on pivoting joints at some height above the ground. The height may be determined based on the racetrack conditions or other safety testing or requirements. The bottom end of the pole (which could be underground), is pivoted against a hydraulic cylinder with extremely high pressure capability. The piston rod may be depressed by the bottom end of the pole, and the fluid in the system is compressed to absorb the energy of the arrestment. The hardware for this system may be mounted above or below ground. 
         [0039]    Attach Net/Fence to SAFER Barrier Concept. 
         [0040]    This concept provides an alternate mounting orientation of the net involving mounting the bottom edge of the safety net/fence system to the inside top edge of the SAFER Barrier. One example is shown in  FIG. 16 . In most instances, the SAFER barrier consists of structural steel tubes welded together in a flush mounting, strapped in place to the existing concrete retaining wall. (Behind these tubes are bundles of closed-cell polystyrene foam, placed between the barrier and wall. The theory behind the design is that the barrier absorbs a portion of the kinetic energy released when a race car makes contact with the wall and dissipates the energy along a longer portion of the wall, reducing the impact energy to the car and driver, and preventing the car from propelling back into traffic on the racing surface.) The purpose of mounting the net to the inside top edge of the SAFER barrier is to “borrow” some of the energy absorbing capacity of the existing SAFER Barrier and use it for dissipating the energy of a car hitting the fence above. It would also solve a potential problem of a car leaving the track and becoming tangled in the gap behind the SAFER Barrier, by closing-in the area in question with the lower edge of the fence. An additional benefit to mounting the net at this location is that an extra three feet (approximately) of runout could be added to the system by including the space above the foam cartridges and the wall as part of the fence system runout. 
         [0041]    Large Textile Brake Concept. 
         [0042]    In this concept, a large, horizontal textile brake is fastened to the pole structure at the top, and to the concrete wall or SAFER barrier at the bottom. An example is shown in  FIG. 17 . The net or fencing material in this embodiment is made integral to the “tearing” side of the textile brake, so that if a car leaves the track and contacts the net, the textile brake would shear at the top and bottom to absorb the energy of the impact. Due to manufacturing limitations, the system may need to be made in sections, and the nets should be securely fastened to each other at net boundaries using any appropriate system or method. The system would be easy to reset after an impact, as a whole damaged section could be removed and replaced with a new one in a relatively short period of time. 
         [0043]    Pivoting to Pole Section with Leaf Spring Energy Absorber Concept. 
         [0044]    The pivoting top pole with leaf spring concept absorbing energy in the pole structure by providing a pivoting or flexible top portion of the pole. As shown in  FIG. 48 , in one embodiment, a two-part pole is made with a pivoting joint that allows the top portion to pivot (or flex) relative to the fixed bottom portion. The net or fence is rigidly fastened between the top movable portion of the pole and the fixed concrete wall below. A leaf spring may be anchored at the bottom, and made to contact the top portion so that as the net deflects to absorb the energy of a crash, the top portion of the pole pivots and deflects downward. The leaf spring would then apply force to the top portion of the pole, absorbing the energy of the crash, and assisting in returning the system to the upright position. 
         [0045]    Large, Collapsible Airbag Concept. 
         [0046]    For track installations with large catch fence areas that do not have spectator bleachers behind them, large, collapsible airbags may be used to cushion the impact of cars leaving the track. Large, quick-deflating airbags could be installed above the SAFER barrier that have flaps that would break open upon impact and absorb the energy of a car hitting the bag. One example of such a configuration (prior to deployment of an airbag) is shown in  FIG. 19 . These airbags may be similar to airbags used in the movie industry to cushion stunt performers from falls. The large vertical surface area of the bags could present an ideal spot for sponsor advertising as well 
         [0047]    Although multiple embodiments are described and provided above, it should be understood that other options may be designed that are considered within the scope of this invention. For example: 
         [0000]    
       
         
               
               
             
               
               
             
           
               
                   
               
               
                 No. 
                 Idea Description 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 Tighter chain link fence 
               
               
                 2 
                 Chain link encased in plexiglass (like safety glass) 
               
               
                 3 
                 “Play knife” concept—compresses with pressure—pops back up 
               
               
                 4 
                 Extend SAFER barrier higher with clear tubes or panels 
               
               
                   
                 (something like fiberglass) 
               
               
                 5 
                 Fence netting more like SAFER barrier 
               
               
                 6 
                 “Catcher's mitt” concept 
               
               
                 7 
                 Basic rigging 
               
               
                 8 
                 Rapid vertically deploying net based capture system 
               
               
                 9 
                 Hydraulically counteracted pivoting pole system 
               
               
                 10 
                 Tie existing cables into a modified cable arrestor system 
               
               
                 11 
                 Ballistic netting/fencing release attached to energy absorbers 
               
               
                 12 
                 Multilayered approach—clear plexiglass and SAFER barrier 
               
               
                   
                 w/spider web net and energy absorber 
               
               
                 13 
                 Giant curtains (like plastic refrigerator curtains) 
               
               
                 14 
                 Giant Air Blower/Air Knife 
               
               
                 15 
                 Vertical links—transparent super fibers 
               
               
                 16 
                 C-shaped fence design 
               
               
                 17 
                 Use large airbags along areas without spectators (w/advertising?) 
               
               
                 18 
                 Nylon tapes with memory capability 
               
               
                 19 
                 Chinese finger cuffs 
               
               
                   
               
             
          
         
       
     
         [0048]    Changes and modifications, additions and deletions may be made to the structures and methods recited above and shown in the drawings without departing from the scope or spirit of the invention and the following claims.