Patent Document

CROSS-REFERENCE  
       [0001]     This application claims the benefit of U.S. Provisional Application Ser. No. 60/775,577 filed on Feb. 21, 2006, the entire contents of which is incorporated herein by reference. 
     
    
     BACKGROUND  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates generally to moving objects and devices for use therewith, and more particularly, to methods and devices for decelerating moving vehicles.  
         [0004]     2. Prior Art  
         [0005]     Along many highways, exits are provided for runaway trucks or other types of vehicles. Once a vehicle takes such an exit, it enters a stretch of a road that is filled with relatively fine sand of an appropriate depth. As the runaway vehicle enters the sand-filled portion of the road, it quickly begins to decelerate and slow down and after a relatively short distance it comes to rest. The deceleration of the vehicle is caused primarily by the process of “sinking” the vehicle tires into the sand, and forcing it to continuously “climb the height of the sand in front of it, i.e., a height equal to the sinking depth of the tire. The kinetic energy of the vehicle is absorbed primarily by the friction forces generated within the displacing sand. This process is fairly similar to an uphill travel of a vehicle, which would decelerate a non-powered vehicle and eventually bring it to rest. The amount of deceleration, i.e., the rate of slow-down, is dependent on the uphill slope. For the case of a sand-filled road, the amount of deceleration that can be achieved is dependent on the depth of the sand and the mechanical characteristics in terms of the amount of resistance that it can provide to its displacement by the tires.  
         [0006]     As the vehicle travels along the sand-filled road, the vehicle usually experiences a fairly bumpy ride, since the sand cannot be made and maintained perfectly flat and perfectly homogeneous or protected from contaminants carried by the wind and rain and also by an uneven absorption of moisture. Another major disadvantage of the sand is that due to the relatively small friction that it provides between the tire and the roadway, the tires can easily skid sideways and slip, particularly if the driver attempts to use the brakes, and the vehicle may easily be rendered minimally controllable while slowing down. As a result, accidents, such as overturning and jackknifing, can occur while the vehicle is being brought to rest. The skidding, slipping and partial loss of control becomes increasingly more probable with increased initial speed of the vehicle as it enters the stretch of sand-filled road.  
         [0007]     In addition, a depth of sand that is most appropriate for a certain vehicle weight, number of tires, and/or tire size may not be appropriate for other vehicles having a significantly different weight, number of tires, and/or tire size. For example, a road with a depth of sand that is appropriate for a heavy truck will decelerate a light vehicle too fast and can therefore result in injury to the passengers due to the rapid deceleration and/or most likely due to the vehicle loss of control. The optimal depth of the sand is also dependent on the initial speed of the vehicle. If a vehicle enters the sand-filled road with a relatively slow speed, then it would be best for the depth of sand to be relatively small, so that the vehicle is brought to stop as slowly as the length of the sand-filled road allows. Other factors also contribute to the optimal design of such sand-filled roads such as the weight of the vehicle, the number and size of the tires, etc. In short, to achieve an optimal condition, a sand-filled road has to be tuned to the type of the vehicle, its entering weight and initial velocity. In addition, the road and sand conditions have to be regularly monitored and maintained. Such conditions cannot obviously be met for roads that are constructed for general use and are subject to various environmental conditions. Such sand-filled roads are in use in numerous highways and are particularly located where the downward slope of the road is high and heavier vehicles such as trucks are prone to run away and are used as the means of last resort.  
         [0008]     Such sand-filled roads are not, however, suitable for fast moving vehicles such as airplanes. For the case of airplanes, other issues may also arise. For example, the load on each tire is usually much larger than road vehicles; the relative distance between the tires may be smaller than those of road vehicles, thereby rendering them more uncontrollable; the center of mass of the plane may be higher than that of road vehicles, thereby making them more prone to tipping over; etc. In addition, and particularly for fast moving planes, the load applied to the tires keep varying due to the suspensions and the lift action, and therefore may cause a ripple to be formed on the surface of the sand-filled road, thereby making the ride even more bumpy and uncontrollable. In addition, the sand-filled section of the runway needs to be re-leveled after each use. In short, sand-filled roads are not appropriate and practical for fast moving vehicles in general and for airplanes in particular.  
         [0009]     To overcome the aforementioned shortcomings for airplanes, runway segments have been added to the end of test runways that are constructed with a special type of concrete that collapses in a more or less controlled manner under the load of the airplane tire. Such runway segments solve some of the aforementioned problems of sand-filled roadways. However, such runway segments leave some of the major aforementioned problems unsolved and they even create some new problems and hazards. For example, the problem of lack of control is only partially solved by reducing the skidding potential caused by the sand. However, the collapsed concrete tends to constrain the tire to travel, more or less, in the generated “groove,” making it difficult for the plane to maneuver (turn) sideways due to the resistance that the uncrushed “concrete wall” provides against the tire as it attempts to turn sideways. In addition, the concrete material cannot be formed such that it is sufficiently homogeneous to prevent bumpy rides. In addition, the collapsible concrete runway can only be optimally formulated and constructed for a certain airplane with a certain total weight and certain initial velocity as it reaches the collapsible segment of the runway.  
         [0010]     Furthermore, once the collapsible segment of the runway is used by a “runaway” plane during landing or takeoff, the damaged segment has to be repaired before the runway can be opened to traffic. Otherwise, the damaged segment would pose a hazardous condition for the next runaway plane or even for a plane that could have stopped if a regular runway segment was present in place of the collapsible segment. In addition, while the repair crew is repairing the damage, any takeoff or landing would pose a hazardous condition for the repair crew and the plane. The use of the runway must therefore wait for the completion of the repairs, including the time required for the proper setting of the added or replaced sections of the concrete and inspection of the final condition of the runway. In short, the operation of the airport must be significantly curtailed for a significant length of time, and if the airport has only one runway, the entire operation of the airport has to be suspended until the damaged sections of the collapsible runway has been repaired. In short, such collapsible runway segments have major technical difficulties for safe operation and even those technical problems are one day solved, they are still effectively impractical due to the required relatively long periods of closure after each use and the related economical costs involved.  
         [0011]     A need therefore exits for reusable runways and driveways that can slow down or bring to stop a “runaway” vehicle or to simply stop a vehicle in less distance than would be otherwise possible relying on conventional braking techniques. For high-speed approaches, particularly for airplanes, it is also essential that the ride be as smooth as possible and that the vehicle stays fully controllable during the entire time it is being decelerated. It is also highly desirable that the runway or driveway parameters be readily adjustable to optimally match the type, weight and initial speed of the vehicle. Such adaptable runway segments are particularly important for planes for the aforementioned reasons and in practice, the parameters of the runway segment can be readily adjusted by the air traffic controller or even by the pilot since all the required information about the plane and its flight conditions is known prior to landing and takeoff. The information may even be automatically transmitted from the plane by a wireless means to a central processor. In addition, if the plane is experiencing some type of malfunction or is damaged, the runway segment may be adjusted for optimal performance with each specific condition. Such changes in the runway parameters may be achieved manually or automatically before the plane reaches the runway segment or even as it is traveling along the runway.  
         [0012]     Such runway segments may even be placed along the entire length or a portion of the runway (or other road surface) to routinely assist in the deceleration of aircraft (or other vehicles), thereby reducing their tire and brake wear. The equipped runway segments may also be kept inactive, thereby acting as a regular (solid) segment of the roadway surface, and be activated only when needed, such as in an emergency.  
       SUMMARY  
       [0013]     Accordingly, a modular apparatus for slowing a vehicle is provided. The apparatus comprising: a chassis; a surface movably disposed on the chassis; and potential energy storage means contained within the chassis and operatively connected to the movable surface for converting a kinetic energy of the vehicle into potential energy upon movement of the movable surface thereby slowing the vehicle.  
         [0014]     The apparatus can further comprise means for mounting the chassis to an underlying surface.  
         [0015]     The apparatus can further comprise means for mounting the chassis to another chassis of another modular apparatus.  
         [0016]     The surface can comprise a plurality of surfaces arranged in the direction of travel and each movably disposed on the chassis.  
         [0017]     The chassis can have a top surface upon which the vehicle travels that is substantially parallel with an underlying surface upon which the chassis is placed.  
         [0018]     The chassis can have a top surface upon which the vehicle travels that has a first end having a first height from an underlying surface upon which the chassis is placed that is less than a second end having a second height from the underlying surface, the second end being offset from the first end in the direction of travel of the vehicle. The first height can be substantially zero. The second height can be substantially the same height as a first end of a second chassis connected to the second end in the direction of travel.  
         [0019]     The chassis can include at least a portion of a top surface upon which the vehicle travels with no movable surface disposed thereon.  
         [0020]     Also provided is a method for slowing a vehicle. The method comprising: positioning a chassis over an underlying surface; movably disposing a surface on the chassis; and converting a kinetic energy of the vehicle traveling over the movable surface into potential energy upon movement of the movable surface thereby slowing the vehicle.  
         [0021]     The method can further comprise mounting the chassis to another chassis of another modular apparatus.  
         [0022]     A plurality of surfaces can be movably disposed on the chassis and arranged in the direction of travel.  
         [0023]     The method can further comprise providing a transition from the underlying surface to the chassis for the vehicle to travel on.  
         [0024]     Still yet provided is a modular apparatus for slowing a vehicle. The apparatus comprising: a chassis; a plurality of surfaces, each movably disposed on the chassis and extending in a direction of the vehicle&#39;s travel; and potential energy storage means associated with at least some of the plurality of movable surface, the potential energy storage means contained within the chassis and operatively connected to at least some of the plurality of movable surfaces for converting a kinetic energy of the vehicle into potential energy upon movement of the plurality of movable surfaces thereby slowing the vehicle.  
         [0025]     The apparatus can further comprise means for mounting the chassis to an underlying surface.  
         [0026]     The apparatus can further comprise means for mounting the chassis to another chassis of another modular apparatus.  
         [0027]     The chassis can have a top surface upon which the vehicle travels that is substantially parallel with an underlying surface upon which the chassis is placed.  
         [0028]     The chassis can have a top surface upon which the vehicle travels that has a first end having a first height from an underlying surface upon which the chassis is placed that is less than a second end having a second height from the underlying surface, the second end being offset from the first end in the direction of travel of the vehicle. The first height can be substantially zero. The second height can be substantially the same height as a first end of a second chassis connected to the second end in the direction of travel. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]     These and other features, aspects, and advantages of the apparatus and methods of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:  
         [0030]      FIG. 1  illustrates a schematic sectional view of a preferred implementation of a reusable and adaptive runway of the present invention.  
         [0031]      FIG. 2  illustrates a schematic of a single runway panel and support and control elements corresponding to the panel.  
         [0032]      FIG. 3  illustrates a schematic of the single runway panel of  FIG. 2  under the weight of a vehicle tire.  
         [0033]      FIG. 4  illustrates a schematic cross section of another preferred implementation of the reusable and adaptive runway of the present invention.  
         [0034]      FIG. 5  illustrates a schematic cross section of yet another preferred implementation of the reusable and adaptive runway of the present invention.  
         [0035]      FIG. 6  illustrates a schematic cross section of still another preferred implementation of the reusable and adaptive runway of the present invention.  
         [0036]      FIG. 7  illustrates a schematic cross section of another implementation of the reusable and adaptive runway of the present invention.  
         [0037]      FIG. 8  illustrates a schematic cross section of still another preferred implementation of the reusable and adaptive runway of the present invention.  
         [0038]      FIG. 9  illustrates a graph showing a preferred relationship between spring displacement and force for the spring elements of the reusable and adaptive runway of the present invention.  
         [0039]      FIG. 10  illustrates a schematic cross section of still another preferred implementation of the reusable and adaptive runway of the present invention.  
         [0040]      FIG. 11  illustrates a schematic cross section of still another preferred implementation of the reusable and adaptive runway of the present invention.  
         [0041]      FIG. 12  illustrates a schematic cross section of still yet another preferred implementation of the reusable and adaptive runway of the present invention.  
         [0042]      FIG. 13  illustrates a sectional view of a vehicle tire having means for converting kinetic energy of the vehicle to potential energy, similar to that of the RAR.  
         [0043]      FIG. 14  illustrates an embodiment of a modular RAR section block.  
         [0044]      FIG. 15  illustrates a plurality of the RAR section blocks of  FIG. 14  positioned side by side.  
         [0045]      FIG. 16  illustrates a connection means between two adjacent modular RAR section blocks.  
         [0046]      FIG. 17  illustrates a transition modular RAR section block positioned before the modular RAR section block of  FIG. 14 .  
         [0047]      FIG. 18  illustrates a plurality of transition modular RAR section blocks positioned before the modular RAR section block of  FIG. 14 . 
     
    
     DETAILED DESCRIPTION  
       [0048]     Although this invention is applicable to numerous and various types of roadways and surfaces, it has been found particularly useful in the environment of runways for aircraft. Therefore, without limiting the applicability of the invention to runways for aircraft, the invention will be described in such environment. Those skilled in the art will appreciate that the RAR of the present invention can be used on roadways for automobiles and trucks and for other wheeled vehicles. The RAR of the present invention can also be adapted for use with trains where the panels described below are proximate the rails upon which the trains travel.  
         [0049]     A schematic of the side view of a preferred RAR illustrating its basic principles of operation is shown in  FIG. 1 . In this illustration, the RAR  100  segment is shown positioned at the end of a typical (fixed) runway  101 . At the end of the fixed runway  101 , one or more transition runway panels  102  are to be installed in a transition segment  103  of the RAR  100 . The function of the transition segment  103  of the RAR  100  is to provide for a smooth transition for a vehicle during its motion from the fixed segment of the runway  101  to the RAR segment  100 . In general, more than one transition runway panel  102  is preferred in order to make the vehicle motion smooth as it enters the RAR segment  100  of the runway, i.e., in order to prevent the tires from suddenly striking the RAR segment  101  which would otherwise form a step like configuration immediately following the fixed runway segment  100 .  
         [0050]     The transition runway panels  102  are constructed with a surface panel  102  which make an angle α ( 104  in  FIG. 1 ) with the surface of the fixed runway  101 , rising to the height H ( 105  in  FIG. 1 ). Under the transition runway panel(s)  102  are elastic elements, motion constraining mechanisms, braking mechanisms, and all other components, collectively shown in  FIG. 1  as element  106 , which hereinafter is referred to as the runway panel “support and control assembly.” The details of the support and control assembly  106  is provided in  FIG. 2 . The support and control assembly  106  is mounted on a runway foundation  107 . Following the transition runway panels  102 , the regular runway panels  108  are positioned. The runway panels  108  are held in place above the foundation  107  by support and control elements  109 , which are very similar in function and construction to the support and control elements  106 . In  FIG. 1  and to simplify the illustration, the mechanisms used to attach the transition panels  102  to the fixed runway  101  and to the other transition  102  and regular runway panels  108  are not shown. These details are provided in the ensuing illustrations. In addition, it is understood that the outermost side of the runway panels  108  are preferably not exposed. In practice, the sides of the runway panels  108  are preferably protected from the elements without the addition of any motion restraining elements such as with simple bellows. In addition, it is understood that in  FIG. 1  only one runway panel  108  is shown along the width of each segment of the RAR  100 . However, it is understood that more than one runway panel  108  may be positioned side by side along the width of each runway panel segment  108 .  
         [0051]     The structure of the simplest type of support and control elements  106  and  109  is shown in the schematics of  FIGS. 2 and 3 . Such a support and control element consists of one or more spring elements  110  and one or more braking elements  111  connecting the runway panels  102  and  108  to the runway foundation  107 . As the vehicle tire  112  leaves the fixed portion of the runway  101 , it first rolls over the panels  102  within the transition segment  103  of the RAR  100 , and then rolls over the regular RAR panels  108  as shown in  FIG. 3 . The relatively small angle α ( 104 ) ensures that the transition between the transition panel  102  and regular panel  108  segments of the RAR  100  is relatively smooth. Depending on the weight W ( 114 ) being born on the tire  112  and the total spring rate provided by the spring elements  110 , the panel  102  ( 108 ) is displaced downward a distance D ( 113 ) as shown in  FIG. 3 . The spring rate is preferably selected, i.e., set by a spring rate adjustment mechanism (not shown) such that the amount of downward displacement D ( 113 ) is fairly close to the height H ( 105 ) of the regular panels  108 . The amount of potential energy PE stored in the spring elements  10  is readily shown to be 
 
 PE= ½ kD   2   (1) 
 
         [0052]     where k is the effective spring rate of the spring elements  110 , assuming that the spring elements  110  are not pre-loaded. If the spring elements  110  are pre-loaded a distance D 0 , then the potential energy stored in the spring elements  110  is readily shown to be 
 
 PE= ½ k ( D+D   0 ) 2 −½ kD   0   2   (2) 
 
         [0053]     In general, the spring elements  110  are desired to be pre-loaded in order to reduce the amount of displacement D for a desired level of potential energy PE.  
         [0054]     The source of potential energy PE that is stored in the spring elements  110  is the kinetic energy of the vehicle. Therefore, the kinetic energy of the vehicle is reduced by the amount of potential energy PE that is stored in the RAR panel  102  ( 108 ). Obviously, the panel  102  ( 108 ) and thereby the spring elements  110  have to be locked in their displaced position shown in  FIG. 3 . Otherwise, as the tire  112  passes over the panel  102  ( 108 ), the panel  102  ( 108 ) could transfer most of the stored potential energy back to the tire, thereby causing the RAR system to have a minimal effect in absorbing the kinetic energy of the vehicle, i.e., from slowing the vehicle down. Here, the locking action is intended to be provided by the brake  111 , which is actuated by the braking force  115 .  
         [0055]     The preferred length of each of the RAR panels  102  ( 108 ) relative to the size of the tire  112  and the preferred methods of connecting the panels  102  ( 108 ) together and to the runway foundation  107  will be described later.  
         [0056]     The components shown in the support and control elements  106  and  109  are the minimum type of elements that allow for the proper operation of the RAR  100 . Additional elements, such as those previously mentioned may, however, be added to provide for features that may be desirable depending on the operational requirements of each runway, the level of automation that is desired to be incorporated into the overall design, for allowing for the adjustment of one or more of the parameters of the system, its effective height H ( 105 ), the configuration of the system, etc. In the remainder of this description, various preferred design configurations and the types and ranges of parameters are provided as a function of various desired operating conditions.  
         [0057]     The operation of such reusable and adaptive runways (RAR)  100  is equivalent to the vehicle traveling along an inclined surface, thereby transforming its kinetic energy into potential energy proportional to the vertical height that its center of mass attains. In the present invention, the kinetic energy of the vehicle is transformed into potential energy stored in the deforming elastic elements, i.e., the springs  110 . In certain situations, it may be desired to provide friction (braking action) and/or viscous damping elements that are positioned in parallel or in certain cases in series with the elastic elements, thereby dissipating a certain portion of the kinetic energy of the vehicle. Yet in other certain situations, it may be desired to use kinetic energy storage elements such as flywheels in series or in parallel with the elastic elements or even in place of the elastic elements. In a similar design, opposing magnet or magnets and coils (i.e., linear or rotary motors) may be used in parallel or in series with one or more of the aforementioned elements. Yet in certain other situations, electrical energy generators may be positioned in series or parallel with the elastic elements or in place of the elastic elements, or in series or parallel with the kinetic energy storage elements or in place of the kinetic energy storage elements. The electric energy generators or electric actuation devices (or in fact any other means of actuation) may be used as means to absorb part or the entire kinetic energy that is transferred to the RAR panels, or they may be used in part or entirely as means of controlling the rate of such energy transfers. The latter means of control is usually aimed at achieving a smooth motion for the vehicle. In general, the spring rates, viscous damping rates, and the characteristics of any one of the aforementioned elements may be constant or adjustable. Such means of adjustment of the characteristics and parameters of the aforementioned elements may be used to adjust the characteristics of the RAR  100  to their near optimal conditions for each approaching vehicle, its speed, and operating condition. The aforementioned elements may also have linear or nonlinear characteristics. The advantages and disadvantages of a number of aforementioned combinations and the general characteristics that they can provide the RAR system is described later in this disclosure.  
         [0058]     In short, a number of combinations and configurations of one or more elastic elements, one or more kinetic energy storage elements, one or more viscous damping elements, one or more braking elements, one or more electrical or hydraulic or pneumatic motors or their combination, and one or more electrical energy generators may be positioned in series or in parallel to provide the desired effect of “absorbing” the kinetic energy of the vehicle.  
         [0059]     The RAR panels  102  and  108  are preferably constructed with relatively rigid but lightweight materials as relatively rigid but lightweight structures. The surface of the panels are preferably coated with appropriately formulated material to enhance endurance, increase friction and decrease wear.  
         [0060]     The RAR surface panels  102  ( 108 ) may be constructed with panel or panel like elements that are relatively free to move relative to each other, particularly in the vertical direction and in rotation about a transversely directed axis (perpendicular to the vertical and longitudinal axes of the runway or roadway). In such a configuration, the horizontal motion of the panels  108  relative to each other and relative to the runway foundation  107  is preferably controlled by relatively stiff elastic elements  125  ( FIG. 4 ), preferably with a considerable amount of (preferably viscous like) damping (such as with synthetic rubber type of materials) in order to control the panels from slipping in the longitudinal direction under the rotating tire. Mechanical stops may also be provided to assist in the control of the horizontal motion of the RAR panels  108 . Such a RAR panel configuration is suitable when the size of the panels  108 , particularly their length (measured along the length of the runway) is relatively small compared to the size of the vehicle tire such that at any point in time, the tire is in contact with more than one panel  108 , preferably with at least three panels  108 . The latter condition is necessary in order to assure a smooth motion for the vehicle as the tire moves from one panel  108  to the other, causing the panels  108  to generally conform to the shape of the tire as shown in  FIG. 4 , rather than causing the tire to move up a step like path.  
         [0061]     In another embodiment of this invention, the surface panels  102  ( 108 ) are hinged together as shown in  FIG. 5  along the length of the runway to allow for their relative rotation about their transverse axes in order to accommodate to the shape of the traveling tire  112 . The panels  108  (or  102 ) are connected with hinges  120  to allow their relative rotation. Such a rotation is required for the smooth operation of the RAR so that as the tire moves over the first panel  108  ( FIG. 5 ) and depresses a certain amount, the next panel  108  is rotated counterclockwise the required amount to allow such vertical displacement of the first panel  108  without resulting in a step to be formed between the two panels  108 . The hinge  120  or at its connections to the panels  108  or the panels  108  themselves may be constructed with certain amount of flexibility to allow the change in the horizontal projection of the longitudinal length of the panels due to the relative rotation of the panels  108  to be compensated.  
         [0062]     In yet another embodiment of the present invention, the panels are attached to the underlying structure (foundation  107 ) of the runway by means of mechanical elements, i.e., linkage or other types of mechanisms, such that their motion relative to the foundation is constrained in certain manner to allow for the smooth travel of the tire over the panels. An example of one of numerous possible types of such motion constraint mechanisms is shown in  FIG. 6 . This mechanism is constructed with linkage type of mechanisms. In  FIG. 6 , the side view of only one runway panel  108  ( 102 ) is shown. In this design, one side of the panel  108  ( 102 ) is attached with two links  136  and  137  which are hinged together at the hinge  134 . The link  136  is attached to the runway panel  108  ( 102 ) by the hinge  130 . The link  137  is attached to the runway foundation  107  by the hinge  132 . The opposite end of the panel  108  ( 102 ) is attached to the foundation  107  by links  138  and  139  which are hinged together with hinge  135 . In turn, the link  138  is attached to the panel  108  ( 102 ) by hinge  131  and link  139  is attached to the foundation  107  by hinge  133 . The pair of links  136  and  137  and the pair of links  138  and  139  reduce the total degree of freedom of the panel for motion in the vertical plane from three degrees of freedom (two displacements and one rotation) to two degrees of freedom, i.e., the motion of the panel in the vertical plane is constrained by the linkage mechanism shown in  FIG. 6  to two degrees of freedom. As a result, other elements of the mechanism  106  ( 109 ) (not shown in  FIG. 6  for clarity), mostly the spring elements  110 , provide fewer constraining forces to provide for the aforementioned desired motion of the panels as the tire travels over the panel. Those skilled in the art will appreciate that the elastic elements are operatively connected with the panels (or belt) to convert the kinetic energy of the vehicle to potential energy. Thus, the elastic elements can be directly connected to the panels (or belt) or connected to the links in way which deforms the elastic element(s) upon movement of the links.  
         [0063]     It should be noted that in general, the panels  108  ( 102 ) are desired to possess two degrees of freedom in motion in the vertical plane. This is the case since as the tire travels over the panels  108  (except a panel  102  located immediately following the fixed segment of the runway), the panels  108  are desired to undergo a motion which is essentially a counterclockwise rotation that brings their edge closest to the tire downward, followed by a clockwise rotation that brings the opposite edge of the panel downward until the panel is essentially horizontal. It is readily observed that if the panels  108  are short relative to the size of the tire  112  as shown in  FIG. 4 , then during the above counterclockwise and clockwise rotations, the panels  108  would also undergo a vertical displacement such that the panels are essentially tangent to the periphery of the tire  112  at all times. However, panels  108  that are long relative to the size of the tire  112  such that the tire  112  may be located at times entirely over the surface of only one panel  108 , would undergo a more or less pure counterclockwise rotation as the leading edge of the panel  108  closest to the tire  112  is pushed downward to essentially the maximum set depth  105 , and as the tire  112  moves over the panel  108 , the panel  108  would then begin to rotate clockwise about the same leading edge until the panel  108  is essentially horizontal. The configuration of the panels  102 ( 108 ) is shown by way of example only and not to limit the scope or spirit of the present invention. For example, as shown in  FIG. 12 , all or a significant portion of the panels can be arranged at an angle α such as the transition panel  102 , or alternatively, all of the panels could be arranged flat (e.g., α=0), such as panels  108 . In the alternative configuration of  FIG. 12 , the panels  102  are not attached to each other but are instead all hinged to the roadway for pivotal movement therewith.  
         [0064]     Another class of mechanism that may be used to constrain the motion of the aforementioned longer runway panels  108  ( 102 ) relative to the runway foundation  107  to the aforementioned sequential counterclockwise and clockwise rotation about the leading edge  140  closest to the incoming tire  112 , as shown in  FIG. 7 . In this class of constraining mechanisms, the motion of the leading edge  140  of the panel  108  is constrained to a vertical motion, while the panel  108  ( 102 ) is free to rotate about the leading edge  140 . In the mechanism shown in  FIG. 7 , the motion of the edge  140  is constrained to the vertical direction by the sliding joint  141 , which consists of the sliding element  143  and the guide  144 . The sliding element  143  is hinged to the edge  140  of the panel  108  ( 102 ) by a rotary joint  142 , thereby allowing the panel to rotate counterclockwise as the edge  140  is pushed down to the previous panel and once the tire  112  begins to move over the panel  108  ( 102 ) shown in  FIG. 7 , to allow the panel  108  to rotate in the clockwise direction until it is essentially horizontal and depressed a distance H  105 . A plurality of such motion constraint mechanisms may be constructed. In fact, the mechanism shown in  FIG. 7  is selected only for the purpose of demonstrating the mode of operation of such motion constraint mechanisms and does not constitute the preferred embodiment unless the sliding joint is constructed as a living joint. This is the case since sliding joints constructed sliding and guiding elements, even together with balls or rollers or other anti-friction constructions, are much more susceptible to sticking, generally generate more friction forces, are harder to keep free of dirt and contaminants, and are generally larger and heavier, thereby are generally desirable to be avoided. The preferred mechanisms are constructed with rotary joints, such as in the form of one of many well-known linkage mechanisms that generate nearly straight-line motions.  
         [0065]     Motion constraining mechanisms may also be preferably used to constrain the motion of the panels  108  ( 102 ) to rotations about axes perpendicular to the longitudinal and vertical directions, i.e., clockwise and counterclockwise rotations as illustrated in  FIGS. 4, 5 ,  6 , and  7 . In the schematic of  FIG. 8 , the edge  150  of a runway panel  108  ( 102 ) along the width of the runway  107 , i.e., as viewed in a direction parallel to the longitudinal direction of the runway, is illustrated. To limit the motion of the runway panel to the above rotations, the motion constraining mechanism constrains the edge  150  to motions in the vertical direction while keeping the edge  150  parallel to the horizontal plane (here, for the sake of simplicity and without intending to place any limitation on the design of the runway foundation, the foundation surface is considered to be flat and parallel to the horizontal plane). The simplest linkage mechanism that would provide the above constraining motion, is a double parallelogram mechanism  160  as shown in  FIG. 8 . The mechanism consists of links  153  of equal lengths that are attached to the runway panel  108  ( 102 ) by spherical joints  151 ; links  155  of equal lengths that are connected to the foundation  107  with spherical joints  156 ; and a common link  154  to which the ends of the links  153  and  155  are hinged with rotary joints  152 . One or more double parallelogram mechanisms  160  may be used to constrain the motion of each runway panel  108  ( 102 ).  
         [0066]     In yet another embodiment of the present invention as shown in  FIG. 10 , the panels are replaced with an appropriately sized and relatively flat surfaced chain like or belt like structures  170  that cover a commonly used underlying support structure which is in turn attached to the support and control elements  106  ( 109 ) with or without one or more of the aforementioned motion constraining mechanisms. The use of such chain or belt like surface structures allow for a smoother travel of the tire, similar to the case of shorter panels shown in  FIG. 4 . For example, a continuous belt segment would in effect act similar to panels with very small lengths.  
         [0067]     Hereinafter, the above types of runway surface elements are referred to as runway panels without intending to limit them to any one of the above designs. To those skilled in the art, numerous other “runway panel” design configurations that allow relatively smooth vertical displacement of the underlying surface as the vehicle tire travels over such “runway panel” and thereby affect deformation of appropriately positioned elastic potential energy storage elements similar to the spring elements  110  are possible and are intended to be covered by the present disclosure.  
         [0068]     The runway panels are elastically supported by spring elements that are positioned between the panels and the runway foundation. The elastic (spring) elements may take any form, for example, they may be constructed in a helical or similar form by spring wires of various cross-sections, or they may be formed as torsion or bending springs, torsion bars, or any of their combinations. To optimally control the vertical movement of the runway panels, the spring rates, i.e., the relationship between the applied vertical force and the resulting vertical displacement of the runway panel may be linear or nonlinear. The spring elements may be positioned directly between the runway panels and the runway foundation or act on the mechanical elements that provide motion constraint to the panels. In general, various spring types and configurations may be used to provide various elastic responses upon the application of load (mostly vertical) at certain points on the panel, i.e., to provide the desired effective spring rates in response to the vertical displacement and rotation about an axis directed in the transverse direction.  
         [0069]     The potential energy storage elements can also be the structural elements disclosed in U.S. Pat. No. 6,054,197, the contents of which are incorporated herein by its reference. In general, as shown in  FIG. 11 , the weight  115  of the tire  112  deforms the structural element  200  which is disposed between each panel  102 ( 108 ) and the runway base  107  to store a potential energy therein. The structural element may also itself serve as the braking element where displaced fluid  202  from the interior of the structural element (caused by the deformation) is captured in a reservoir  204  and restricted from returning to the cavity  202 , such as by closing a valve  206  while the structural element is deformed. The structural element  200  is released or reset (extended) by removing the restriction, such as by opening the valve  206  to allow the fluid to flow back into the cavity  202 . Preferably, the structural elements  200  are remotely controlled by a processor  208  operatively connected to a solenoid which operates the opening and closing of the valves  206 . The amount of deformation the structural elements undergo can also be controlled and varied by the processor by controlling the amount that the valves  206  open (i.e., the orifice size is varied). A structural element  200  corresponding to a valve  206  that is partially opened will be more rigid and thus undergo less deformation than a structural element having a corresponding valve  206  that is fully open.  
         [0070]     Each runway panel assembly, i.e., the runway panel, its motion constraining mechanisms and the elastic elements, viscous and dry friction based damping elements, are also equipped with one-way locks, that as the elastic elements are deformed under load, they are held in their maximum deformed position and are substantially prevented from regaining their original configuration as the load is lifted. Such one-way locking mechanisms may be placed at any appropriate position between the runway panels and the foundation or between the runway panels and the mechanical motion constraining elements. The one-way locking mechanisms may also be positioned in parallel with one or more of the elastic elements, or may be constructed as an integral part of one or more of the elastic or damping elements. Regardless of their design and the method of integrating them into the runway panel assembly, the one-way locks serve one basic function. This basic function is to “lock” the depressed runway panels in place and prevent them from “springing” back to their original position. In other words, as the airplane or other vehicle tire displaces a runway panel, the work done by the force exerted on the displacing surface panels (mostly vertically and some in rotation) is to be stored in the spring elements  110  ( 200 ) as potential energy. The function of the aforementioned one-way lock mechanisms is to “lock in” this potential energy by preventing the spring elements  110  ( 200 ) from moving back to their original position. The potential energy stored in the spring elements  110  ( 200 ), neglecting all other commonly present energy losses due to friction, etc., is equal to the kinetic energy that is transferred from the airplane or other vehicle to the spring elements  110  ( 200 ). In general, one or more elastic elements of various types may be used on each runway panel and one or more of the spring elements may be initially preloaded. The primary purpose of preloading of the elastic elements is to reduce the amount of vertical and/or rotational displacement of the runway panels for a given applied load. Another function of selectively preloading one or more of the elastic elements is to create the load-displacement (rotation) characteristics that is optimal or close to optimal for the operation of the runway.  
         [0071]     In the preferred embodiment of this invention, the effective spring rates of each runway panel assembly and the spring preloading are adjustable remotely. The spring rates and preloads may obviously be adjustable manually, particularly for runways that are only used with a few similar types of airplanes.  
         [0072]     In general, the runway panel assemblies are designed such that they do not require motion damping elements such as viscous dampers for their proper operation such as to prevent the bouncing action upon initial tire contact. Such dampers are used to control the response of the runway panel assemblies to the speed of application of the tire load. In any case, minimal damping is desired to be used to make the RAR most responsive to high-speed vehicles. In addition, if the stored potential energy in the elastic elements are intended to be used or harvested, minimal damping is desired to be employed since such dampers would convert a portion of the kinetic energy of the plane into heat, i.e., a type of energy that is difficult to harness as compared to potential energy stored in elastic elements.  
         [0073]     On the other hand, certain runway panel assemblies, particularly those that are located at or close to the portion of the runway over which the plane travels at high speeds, may be desired to be equipped with motion damping elements such as viscous dampers that are appropriately positioned to provide resistance to the displacement and/or rotation of the runway panels for smooth operation. The effective damping rates of these elements are also desired to be adjustable remotely, manually and if possible by a closed-loop control loop.  
         [0074]     When the runway is intended to slow down airplanes upon landing, the plane may first land on a regular (fixed) runway segment and then enter the RAR segment to be slowed or be brought to complete stop. In such cases, it is important that the transition between the two runway segments be as smooth as possible. Such smooth transitions are readily obtained, e.g., by providing higher spring rates for the initial highway panels and/or hinging them to the edge of the regular runway segment and then gradually decreasing the panel spring rates to achieve maximum deflection, i.e., maximum vertical displacement of the runway panels under tire load. As the result, the vehicle begins to slow down smoothly as it enters the RAR segment. Then, as the plane continues to travel along the RAR segment, the runway panels begin to be displaced vertically to their maximum set amount, and the kinetic energy of the plane continues to be transferred to the spring elements, while a certain (usually much smaller) portion of the kinetic energy is dissipated in the viscous damping and/or brake like friction elements. The plane will loose no control since the slowing down process does not involve any skidding or reduction or loss of contact friction between the tires and the runway surface. This is in total contrast with sand-filled roads and collapsible concrete runways that would form certain “pathways” along which the tires are forced to travel. Of course, the RAR may also constitute the entire runway which may be much smaller in length then a conventional runway for the same size aircraft.  
         [0075]     Once the plane has been slowed down to the desired speed or has been brought to rest, the braking mechanisms of the runway panels can be released to slowly bring the panels to their original position. To make the movement smooth and prevent vibration, viscous damping or friction elements may be engaged during this return movement. Alternatively, energy transformation means such as electric generators may be used to transform the stored energy in the elastic elements into usable electric energy.  
         [0076]     On the other hand, the potential energy stored in the elastic element of the runway panels may be used to accelerate a plane during its takeoff. The process is the reverse of the slowing down process. Here, as the tire moves over a depressed runway panel, the panel brakes are released in a controlled manner from the back of each panel to the front as the tire moves over the panel, thereby pushing the plane forward and transferring the potential energy stored in the elastic elements to the plane as kinetic energy. By properly releasing the braking mechanisms, it is possible to transfer most of the stored potential energy to the plane. This process has the effect of allowing the plane to travel along a runway with a downward incline, thereby transferring the potential energy of the plane due to the total drop in the plane elevation to the plane in the form of kinetic energy.  
         [0077]     Both landing and taking off processes using RAR can be seen to be highly energy efficient. During the landing, minimal or no braking is required. During takeoff, a large portion of the required kinetic energy can be absorbed from the RAR. By appropriate selection of the RAR parameters, planes are able to land and take off in relatively short runways. Such runways can therefore be also very useful for the construction of emergency landing and takeoff strips and for aircraft carrier.  
         [0078]     In general, elastomeric or hydraulic type of shock absorbers and bumpers may be used to limit the motion of the runway panels  108  ( 102 ) in the vertical direction to the designated depth H ( 105 ), or prevent excessive lateral motion of the panels or the motion constraint mechanisms, etc. In all situations, such elements are provided in order to smoothly bring these components to a stop and without a sudden shock. For the case of the depth  105  limiting stops, the allowable depth H ( 105 ) is preferably adjustable by a control system that adjusts the system parameters for each particular vehicle and initial speed and operating condition. Such a controller is described above with regard to  FIG. 11 , however, similar control methods may be employed in the other embodiments discussed herein for controlling any or all system parameters.  
         [0079]     In general, the spring elements  110  are preferably preloaded to reduce the required depth H ( 105 ). It is also generally preferable to have springs with nonlinear force displacement characteristics of the general form shown in  FIG. 9  so that as the deformation is increased, the effective spring rate is also increased. Such a spring rate characteristic allows the springs to also act as effective stops as the maximum desired depth H ( 105 ) is approached. The general shape of the desired spring displacement versus spring force curve  163  is shown in  FIG. 9 . The amount of preloading force is indicated by  165 . The spring rate, i.e., the slope of the curve  163  increases with spring displacement. For a given displacement  161  of the spring, the corresponding spring rate k ( 162 ) is given by the slope of the tangent  164  at that point on the curve  163 . As can be observed, by proper selection of the spring  110 , as the displacement is increased (in this case as it reaches the desired amount H ( 105 ), the spring rate becomes very large (somewhere to the right of the point  161 ), where the spring turns into an effective stop.  
         [0080]     In general, more than one wide runway panel  108  ( 102 ) is desired to cover the width of the runway. By utilizing narrower panels, the effective mass that is displaced as the tire moves over a panel is reduced, thereby allowing for the RAR panels to respond quickly. As a result, faster moving vehicles can be accommodated. In which case, the panels are desired to be hinged together as described for the longitudinal sides of the panels, together with similar elastic elements to allow the length variations due to the relative rotation of the panels. In one embodiment of the present invention, the aforementioned relative rotation of the panels along their hinged side edges is allowed. Such an option would provide a certain amount of barrier that the tires have to climb in order to move in the direction of the width of the runway. Such a barrier is desired, particularly if the vehicle is damaged or if the pilot is having problems controlling the vehicle. In an emergency situation, by allowing the depth H ( 105 ) to become larger, a larger stabilizing barrier can be provided for keeping the vehicle on the runway. For such emergency situations, auxiliary barriers positioned on the sides of the runway may also be activated to increase the height of the side barriers. On the other hand, in normal situations, the aforementioned relative rotation of the panels is preferably limited or is totally prevented by the provided hinges and the motion constraining mechanisms.  
         [0081]     Although the RAR is described above having static parameters, such parameters can be variable, either adjusted manually or automatically in response to sensed characteristics. For Example, the RAR can be equipped with sensors for detection of the position, size, and/or velocity of the vehicle before entering the RAR. The information detected by one or more sensors is then input to a processor, which adjusts the parameters of the RAR before the vehicle enters the RAR. The sensors can also continue to monitor the vehicle as it travels on the RAR and adjust the parameters thereof accordingly. For example, one parameter that can be adjusted based on the sensed characteristics is the spring rates of the spring elements  110 . Means for adjusting spring rates of spring elements are well known in the art, such as helical or other passive springs in combination with pressurized gas springs. Another example of a parameter that can be adjusted, is the viscous damping rates of the damper can also be adjusted based on the sensed characteristics. Means for adjusting damping rates are well known in the art, such as providing an electrically actuated orifice change or by using magneto-restrictive fluids in fixed orifice fluid dampers. Yet another example of a parameter that could be adjusted in response to the sensed characteristics is to provide moving stops that vary the amount of movement of the panels  102 ,  108 . The stops can be moved by any means known in the art, such as by using electrically or hydraulically driven lead screws. These characteristics can be varied as a whole (applied to all of the panels  102 ,  108 , or applied to selective panels  102  ( 108 ) and done manually or under the control of a central processor or control unit.  
         [0082]     In certain situations such as in emergency situations when large amount of cargo has to be transported to certain location with heavy cargo aircrafts, the existing runways may be too short to accommodate such aircraft with full load. It is therefore highly desirable to develop the means to decelerate the aircraft over significantly shorter distances. In other cases, there may not even be a runway and some cleared pathway or roadway may be required to be used as landing strip. In all these situations, it is highly desirable to make the landing strip as short as possible.  
         [0083]     A need therefore exists for the development of the modular reusable and adaptive runways (RAR) sections that could be transported to the site and be readily attached to at least a section of the existing runways, roadways or cleared paths to provide the means to smoothly decelerate the aircraft or other vehicles over such sections as described above and in U.S. Pat. No. 6,969,213 entitled “Roadway for Decelerating a vehicle Including an Aircraft,” the entire contents of which is incorporated herein by reference.  
         [0084]     Such modular sections are intended to be attached to the existing surfaces, e.g., existing runway segments, using various means available in the art such as expansion bolts in the case of concrete or asphalt surfaces or even epoxy type of adhesives. The disclosed modular sections are preferably hinged together (when the underlying ground is not firm enough) or attached together with connections allowing certain amount of relative motion, particularly in rotation, when the underlying ground is firm, such as for the case of existing runways.  
         [0085]     One embodiment of the present invention is shown in the schematic of  FIG. 14 . In  FIG. 1 , the modular RAR block  300  is shown to consist of a chassis  301 , preferably with a fully or partially solid (holed) base plate  302 , particularly when the section is to be mounted on relatively soft grounds. Mounted inside the modular RAR block  300  are at least one and preferably a number of runway panels  102 , which are attached to the chassis  301  by hinges  304 . In  FIG. 14 , the panels  102  are shown in their deployed position. Support and control units  109  as discussed above are positioned as shown between in  FIG. 1  between the runway panel  102  and the chassis  301 . The support and control units  109  can also have a separate or an integrated actuation device for varying the deployed position of the runway panel  102 . It is noted that any one of the RAR designs disclosed above or in U.S. Pat. No. 6,969,213 may instead be mounted inside the modular RAR block  300 .  
         [0086]     The chassis  301  may be provided with holes (not shown) in the bottom plate  302  for attachment to the underlying surface  306  with expansion bolts or other similar means known in the art.  
         [0087]     To cover a runway or other pathway section, the modular reusable and adaptive runways (RAR) section blocks  300  are positioned side by side as shown in the top view of  FIG. 15  (although only three of the twenty four blocks are marked in  FIG. 15  with reference numeral  300 , each of the blocks correspondent to the RAR section blocks shown in  FIG. 14 ), and are preferably attached to the underlying surface using one or more of the aforementioned methods.  FIG. 15  is intended to show how the modular section blocks are assembled to cover certain area of the pathway and is similarly extended to cover the entire coverage area. Although the RAR section blocks are shown positioned side by side in the direction of travel (arrow  305 ) and the in a direction perpendicular to such direction of travel, the RAR section blocks can only be positioned side by side in one such direction (e.g., in the direction of travel). The modular reusable and adaptive runways (RAR) section blocks  300  can also be attached together at several points on their adjacent sides, preferably by means  320  that allow certain amount of relative motion, particularly in rotation. For this purpose, various bolt and nut fasteners and other types of fasteners and washers are available that allow certain amount of flexibility and range of rotation.  
         [0088]     For the sake of significantly reducing the amount of work and time that is needed to attach the modular reusable and adaptive runways (RAR) section blocks  300  together, it is highly preferable to have at least a portion of attachment to comprise of interlocking structures that are provided on the sides of the blocks  300  chassis. Such interlocking structures that would also allow certain amount of rotational motion are well known in the art. As an example, one such interlocking structure is shown in  FIG. 16 . In  FIG. 16 , two reusable and adaptive runways (RAR) section blocks  300   a  and  300   b  are shown to be interlocked by a hook  333 , which is fixed to the chassis of the block  300   a , which engages a cylindrical pin  334 , which is fixed to the chassis of the block  300   b . The two blocks  300   a ,  300   b  can readily be interlocked in the field by placing, lifting and rotating either one of the blocks, engaging the hook(s), and laying the lifted block back on the pathway. The above means of interlocking reusable and adaptive runways (RAR) section blocks is seen to allow for small rotational motion of one modular block relative to the other.  
         [0089]     Referring now to  FIGS. 17 and 18 , a transition can be provided to the first RAR section block  300  that is encountered by the vehicle or aircraft to transition from a substantially zero height to the height of the RAR section block  300 . The transition section can be a ramp formed of dirt and asphalt or other pathway surface, such as concrete. In addition, as shown in  FIG. 17 , the transition can be another RAR section block  350  having a tapered chassis  301   a  which tapers from the underlying surface  306  to the height of the subsequent RAR section block  300 . Alternatively, as shown in  FIG. 18 , several transition section blocks  350   a ,  350   b  and  350   c  can be used to transition from the underlying surface  306  to the height of the subsequent RAR section block  300  with each of the transition section blocks  350   a ,  350   b  and  350   c  tapering a portion of the height between the underlying surface  306  to the height of the subsequent RAR section block  300  after the transition. The transition RAR block can have a leading portion  352  thereof which is a smooth surface without the movable panels  102  or the entire transition block can be without transition panels, as shown in transition section block  350   a  in  FIG. 18 .  
         [0090]     While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims.

Technology Category: b