Patent Document

BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates generally to safety and accident prevention, and more particularly, to methods and systems for preventing injuries associated with pole vault falls.  
         [0003]     2. Prior Art  
         [0004]     As shown in  FIG. 1 , in the sport of pole-vaulting, a jumper  10  runs to pick up speed, plants a pole  12  in a vault box  14  located just before a bar  16 , gets to as great a height as possible with the aid of the pole  12 , and attempts to clear the bar  16  and land on the relatively soft mat  18  positioned passed the bar  16  and its supporting posts  20 . Pole-vaulting is an inherently dangerous sport since the athlete may not clear the bar  16  and may land on hard surfaces  22  around the vault box  14  and the running path. Landing on these hard surfaces  22  is most dangerous if the athlete lands on his or her head. Landing on the shoulder or side is less dangerous, but may cause serious injuries since it may be from heights of several feet. Landing on the feet is usually least dangerous, but may still cause injury due to the height of the drop. In general, once the athlete  10  clears the bar  16 , he/she lands over the relatively soft and thick mats  18  (such mats are also usually provided a few feet before the bar  16  on the sides of the running and vault box area), which can protect the athlete from injury if he/she should land in that particular area unless he/she should fall on the head.  
         [0005]     In recent years, there has been a great amount of concern about injuries resulting from pole-vaulting. One suggestion has been to have the athlete wear a helmet. A helmet would provide a certain amount of protection if landing is, for example, on the back or on the side and the head is to hit a hard surface or member. However, a helmet does not provide protection from falls on or nearly on the head, which usually cause the severest types of injuries and which in some cases could be fatal. In addition, wearing of a helmet is very cumbersome and interferes with the sport itself and the athletes generally try to avoid wearing them. Also, helmets cannot be worn in the competitions and do not prevent injuries as a result of falls on the side or feet onto hard surfaces.  
         [0006]     A need therefore exists for a method and system to prevent falling injuries in general, in particular in certain types of sports, and specifically in the sport of pole-vaulting. Such a device should, obviously be designed such that it would not impede the sport itself. The objective of the method and the system disclosed in this invention is to provide such methods and systems for preventing pole vault and other sports related injuries due to falls.  
       SUMMARY OF THE INVENTION  
       [0007]     The basic method of this invention for preventing fall injuries in pole vault is based on deploying a safety soft landing material such as a net over the hard surface areas once the athlete has planted the pole in the vault box and is gaining height. The deployed safety soft landing material must obviously not interfere with the action of the pole while being handled by the athlete or with the athlete him or herself. In one embodiment of the present invention, the triggering mechanism that initiates the deployment of the safety soft landing material is located in the vault box and is activated by the pole. In another embodiment of the present invention, a sensor, for example an optical based sensor located near the bar posts senses an approaching athlete and triggers the deployment mechanism. In this and the previous embodiment, a delay is built into the deployment mechanism to allow enough time for the athlete to gain a certain height before deploying the safety soft landing means. In yet another embodiment of the present invention, a vision system tracks the athlete, and triggers the deployment mechanism once the athlete has gained a certain height. The vision system may also be programmed to only deploy the safety soft landing material if the athlete is about to or may fall over the hard surface areas. In yet another embodiment of the present invention, a trained observer who can foresee a fall over the hard surfaces would manually trigger the deployment of the safety soft landing material. In addition, other sensors may be positioned before and/or after the bar to check for the clearing of the hard surface area, and in case of failure to clear these areas to trigger the deployment of the safety soft landing material. The preferred triggering mechanism consists of more than one of the aforementioned triggering mechanisms in order to provide redundancy and minimize the possibility of malfunction or one of the triggering mechanisms missing a dangerous landing situation.  
         [0008]     A similar safety soft landing material may be provided for deployment over the landing mats to prevent injuries during falls by the head. The preferred triggering mechanisms for deployment for such safety soft landing material are the aforementioned trained observer and/or the computer vision system.  
         [0009]     Accordingly, an apparatus for preventing serious injuries to a person participating in a physical activity at least partially over a hard surface is provided. The apparatus comprising: a material being movable between deployed and retracted positions, wherein the material substantially does not impede the physical activity while in the retracted position and cushions the person from falling onto the hard surface while in the deployed position; detection means for detecting predetermined criteria indicative of a condition which requires deployment of the material into the deployed position; and deployment means for deploying the material over the hard surfaces upon detection of the predetermined criteria.  
         [0010]     Preferably, the physical activity is pole-vaulting and the condition is a likelihood that the person will be injured by falling onto the hard surface.  
         [0011]     In a first configuration, the material is at least one safety net. The hard surfaces preferably comprises a plurality of recesses for containing the safety net while in the retracted position.  
         [0012]     Where the material is at least one safety net, the deployment means preferably comprises a plurality of elastic elements operatively connected to each of the at least one safety net, preloading means for preloading the plurality of elastic elements to retain the at least one safety net in the retracted position, and releasing means for releasing the preloading on the plurality of elastic elements to deploy the safety net into the deployed position.  
         [0013]     Where the material is at least one safety net, the deployment means alternatively comprises a movable frame for retaining the safety net and means for moving the movable frame back and forth between the retracted and deployed positions. Preferably, the movable frame is at least one of rotatable and translational between the retracted and deployed positions.  
         [0014]     In a second configuration, the material is preferably a plurality of cushioning elements. In which case, the deployment means preferably comprises a recess corresponding to each of the plurality of cushioning elements, wherein each of the plurality of cushioning elements are contained in a corresponding recess while in the retracted position, the deployment means further comprising means for extending the plurality of cushion elements from the recess and above the hard surfaces when in the deployed position. Preferably, the deployment means further comprises deploying a balloon from at least a portion of the plurality of cushion elements when the plurality of cushion elements are in the deployed position. Preferably, the deployment means further comprises means for connecting two or more the plurality of cushion elements together when in the deployed position.  
         [0015]     In a first configuration, the detection means comprises an input from a trained observer, wherein the input triggers deployment of the material from the retracted position into the deployed position.  
         [0016]     In a second configuration, the detection means comprises one or more sensors for detecting the predetermined criteria. Preferably, the one or more sensors comprises a vault box sensor operatively connected with a vault box for detecting the insertion of a pole therein for use in pole-vaulting.  
         [0017]     In a third configuration, the detection means comprises a computer recognition system for detecting the predetermined criteria.  
         [0018]     Also provided is an apparatus for preventing serious injuries to a person participating in pole-vaulting at least partially over a hard surface. The apparatus comprising: a material being movable between deployed and retracted positions, wherein the material substantially does not impede the pole-vaulting while in the retracted position and cushions the person from falling onto the hard surface while in the deployed position; and deployment means for deploying the material over the hard surfaces upon detection of the predetermined criteria.  
         [0019]     The apparatus preferably further comprises detection means for detecting predetermined criteria indicative of a condition which requires deployment of the material into the deployed position.  
         [0020]     The apparatus alternatively further comprises a sensor for inputting the deployment means. Preferably, the sensor comprises a vault box sensor operatively connected with a vault box for detecting the insertion of a pole therein for use with the pole-vaulting.  
         [0021]     Still provided is a method for preventing serious injuries to a person participating in a physical activity at least partially over a hard surface. The method comprising: detecting predetermined criteria indicative of a condition which requires deployment of the material into the deployed position; and moving a material from a retracted position to a deployed position upon detection of the predetermined criteria, wherein the material substantially does not impede the physical activity while in the retracted position and cushions the person from falling onto the hard surface while in the deployed position.  
         [0022]     Still yet provided is a vault box for use in pole-vaulting. The vault box comprising: a cavity for insertion of a pole therein; and a switch disposed in the cavity for detection of insertion of the pole in the cavity and for outputting a signal indicating the insertion of the pole. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]     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:  
         [0024]      FIG. 1  illustrates a side view of a pole vault of the prior art having a vaulter attempting to jump over a high bar.  
         [0025]      FIG. 2  illustrates a plan view of a first preferred implementation of a pole vault system of the present invention having a deployable safety net over the hard surfaces in front of the high bar.  
         [0026]      FIG. 3  illustrates a plan view of a second preferred implementation of a pole vault system of the present invention having a deployable net over the mat behind the high bar.  
         [0027]      FIG. 4  illustrates a side view of a third preferred implementation of a pole vault system of the present invention having a deployable net embedded in spaces provided in the hard surfaces in front of the high bar.  
         [0028]      FIG. 5  illustrates a plan view of a segment of the hard surfaces having a recessed safety net of  FIG. 4 .  
         [0029]      FIG. 6  illustrates a sectional view of the segment of the hard surfaces of  FIG. 5  as taken along line  6 - 6  therein.  
         [0030]      FIG. 7  illustrates a schematic of a first deployment mechanism for deploying the safety net.  
         [0031]      FIG. 8  illustrates a schematic of a framed safety net deployed by the deployment mechanism of  FIG. 7 .  
         [0032]      FIG. 9  illustrates a schematic showing a safety net deployed by cables.  
         [0033]      FIG. 10  illustrates a plan view of another preferred implementation of a safety net deployment system, wherein the safety net is deployed by a translational movement.  
         [0034]      FIG. 11  illustrates a plan view of a variation of the safety net deployment system of  FIG. 10 , wherein the safety net is deployed by a rotational movement.  
         [0035]      FIG. 12  illustrates a plan view of another variation of the safety net deployment system of  FIG. 10 , wherein the safety net is deployed by a rotational movement and translational.  
         [0036]      FIG. 13  illustrates a side view of another preferred implementation of a safety net deployment system.  
         [0037]      FIG. 14  illustrates a side view of another preferred implementation of a safety net deployment system.  
         [0038]      FIG. 15  illustrates a plan view of another preferred implementation of a deployment system having cushioning units.  
         [0039]      FIG. 16  illustrates a sectional view of a portion of the system of  FIG. 15  as taken along line  16 - 16  in  FIG. 15 .  
         [0040]      FIG. 17  illustrates a side schematic view of the system of  FIG. 15 .  
         [0041]      FIG. 18  illustrates an alternative configuration of the cross-section of  FIG. 16 .  
         [0042]      FIG. 19  illustrates another alternative configuration of the cross-section of  FIG. 16 .  
         [0043]      FIG. 20  illustrates yet another alternative configuration of the cross-section of  FIG. 16 .  
         [0044]      FIG. 21  illustrates yet another alternative configuration of the cross-section of  FIG. 16 .  
         [0045]      FIG. 22  illustrates still yet another alternative configuration of the cross-section of  FIG. 16 .  
         [0046]      FIG. 23  illustrates a sectional view of a preferred implementation of a vault box of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0047]     Although this invention is applicable to numerous and various types of dangerous activities for which a safety system is useful, it has been found particularly useful in the environment of sports and more particularly in the environment of pole vaulting. Therefore, without limiting the applicability of the invention to sports and pole-vaulting, the invention will be described in such environment.  
         [0048]     Referring now to  FIG. 2 , the major components of a preferred implementation of a fall safety system  100  for preventing fall injuries in pole-vaulting is shown schematically therein. The basic preferred system  100  consists of one or more sensors  101  (which may be a trained observers) that detects the position and/or posture of the athlete during the jumping event to determine whether and/or when a safety net  104  needs to be deployed. The sensory component  101  preferably contains redundancy to minimize the chances of faulty sensory action, particularly, the faulty action corresponding to not triggering a deployment mechanism  103  when a dangerous falling situation has arisen. To minimize the chances of such an event occurring, and since a trainer or coach is almost always required to be present during training, the safety net deployment mechanism&#39;s  103  triggering signal generated by the trained observer is usually the preferred primary or redundant sensory signal.  
         [0049]     The sensory component  101  provides a signal to the safety net deployment triggering mechanism and control unit  102 , indicating the occurrence of an event which is to be used by the triggering mechanism  102  to determine the deployment time. The time of receiving the triggering signal may not be the same as the time that the deployment of the safety net  104  has to be initiated. This is the case when the sensory signal corresponds to an event prior to the athlete raising himself/herself to a considerable height that is either required by the deployed safety net  104  or can result in a dangerous fall. For this reason and for such sensory devices, the triggering mechanism  102  is usually constructed with a programmed delay to allow for the time between the moment that the sensory signal is received and the time at which the safety net  104  has to be deployed. Preferably, the triggering mechanism  102  is constructed with a processor that is readily programmed to accept different sensory inputs and related parameters, such as the location of the sensor  101  relative to the rod  116  and its posts and the runway and the required delay for each sensor  101  and athlete. The aforementioned amount of time may be set to different levels depending on the level of expertise of the athlete, since beginners may not be able to achieve as high heights as the more trained pole-vaulters. The delay may also be computed from a detected trajectory of the athlete using a computer vision system. The triggering mechanism  102  is connected to the deployment mechanism  103 , which receives the triggering signal from the triggering mechanism  102  and activates the deployment mechanism  103 . The deployment mechanism  103  in turn deploys the safety net  104 . In general, there is more than one safety net  104  to be deployed. Preferably, at least two such safety nets  104  are positioned on each side of the runway track and the rod posts  20 . One of the main reasons for having more than one safety net  104  is to achieve faster deployment. The reason for deploying safety nets  104  from both sides of the runway is to minimize the complexity of the safety net design and deployment procedure to avoid interference with the pole as the athlete is using it to achieve height to carry him/her over the rod  16 . Each safety net  104  would generally require one deployment actuation mechanism  103 . In certain configurations of the safety nets  104 , it may be desired to deploy certain safety nets sequentially. For the sake of simplicity, only one safety net  104  and deployment mechanism  103  is shown in  FIG. 2 . All deployment mechanisms  103  are triggered with the same triggering mechanism  102 . It is, however, possible to equip a pole vault site with more than one such fall prevention system for added safety and/or for deployment by an independent sensory system.  
         [0050]     A fall safety system  100  may also be installed behind the jump rod to deploy over the existing mats as shown in  FIG. 3 . Here, the primary purpose for the safety net  104  is to prevent injury during head landing situations. For this reason, the preferred sensory input is from a sensor  101  in the form of a computer vision system, which determines the potential danger and sends a signal to the triggering mechanism to deploy the safety net. Another preferred implementation is where a trained observer, such as the athlete&#39;s coach, generates sensory input. The best protection is provided when both of the above sensory information is provided simultaneously. There is always an option of providing, deploy the safety net before the jump, or deploying a safety net during all jumps. However, if the jump is good and safe, the athletes may prefer to land on the mat rather than on the safety net.  
         [0051]     Where the safety net  104  is deployed during all jumps, a sensor is preferably used to detect that a pole vault event has occurred. Such a sensor may also be used to “arm” the system and to look for the possibility of a dangerous fall occurring. While a manual operator (or trained observer) can be utilized for such a purpose, it is preferred that the pole vault event is automatically detected and the safety net deployed accordingly. The pole vault event can be detected by a computer vision system or by activation of a switch in the pole vault box  14 , as shown in  FIG. 23 .  FIG. 23  shows a pressure sensitive switch  40 . When the pole  12  is planted by the athlete in the vault box  14  the pressure exerted by the weight of the athlete on the pressure sensor  46  generates circuit and output a signal indicating a pole vault event is occurring. The output signal is then input directly to the triggering and/or deployment mechanisms  102 ,  103  or indirectly through a processor or the like.  
         [0052]     One major advantage of the disclosed pole vault fall safety system is that it can be used for athletes of various skills, from beginners to the highly skilled, noting that accidents also happen with the highly skilled athletes. Unlike helmets, the deployed safety net does not interfere with the athlete&#39;s routine and the pole, while protecting the athlete from any type of dangerous fall situations.  
         [0053]     The safety net  104  shown in  FIG. 2  is deployed from the sides of the surfaces that are intended to be covered. In another embodiment of this invention, the safety net  104  is embedded inside the recessed regions provided in the hard surface  22  areas to be covered. The safety net  104  is preferably positioned in narrow pathways deep enough to clear the hard surfaces  22  where the athlete runs over it. The safety net is preferably deployed by preloaded spring elements  108 , which are held in place by a locking mechanism (e.g., a latch), which is released by the safety net deployment mechanism  103 , which is activated by the triggering mechanism  102  once an appropriate signal is received from the sensory device  101 . The position and direction of deployment of the safety net  104  of this embodiment is shown schematically in the side view of  FIG. 4 . The safety net  104  is embedded in relatively narrow spaces provided inside the hard surfaces  22 , from which the athletes are to be protected. The safety net  104  is deployed by the preloaded springs  108  (shown in their deployed position) in the direction  107  from the “stored” position. Some or all of the springs  108  serve two different purposes. Firstly, they are used to deploy the safety net  104  as described above. Secondly, they provide for the required elasticity of the safety net  104  to provide for a cushioning effect in case of an athlete falling over the hard surfaces  22 . In the schematic illustration of  FIG. 4 , the sensory device, triggering mechanism and the deployment mechanisms are not shown for clarity but are considered to be present. In the illustration of  FIG. 4  and for the sake of simplicity, the safety net  104  is shown to be supported solely by the preloaded deployment springs  108 . Alternative methods of supporting the safety net relative to the ground are described later. In the remainder of this description, the term deployment spring is used without intending to limit the choice for this component of the system to only one alternative. Thus, the deployment springs  108  can be any elastic elements.  
         [0054]     The top view of a section of the hard surfaces where the safety net of  FIG. 4  is embedded in the recessed spaces is shown in  FIG. 5 . In this illustration, only a portion of the hard surfaces  22  are shown for simplicity while it should be noted that the safety net  104  of this embodiment is intended to cover all hard surfaces  22  where an athlete may fall onto during an unsuccessful jump.  
         [0055]     In  FIG. 5 , square woven shaped or patterned safety nets  104  are shown by way of example only. It should, however, be noted any other net designs and configurations may also be used and that by the choice of squarely woven nets for  FIG. 5  it is not intended to limit this embodiment to such net shapes and designs. In this schematic, the net  104  is shown to be positioned within the recessed spaces  109  provided in the hard surface  22  areas. In this view, the preloaded deployment springs  108  are not shown.  
         [0056]      FIG. 6  is cross-section  6 - 6  of a portion of  FIG. 5 , showing the profile of a typical recessed space for embedding the safety net  104 . For the sake of simplicity, the deployment springs  108  are not shown. The recess space  109  is shown with its top portion  111   a  (also referred to as surface openings). The recessed section of the hard surface  22  area is usually constructed over a solid foundation  110 . However, the recessed spaces  109  may be provided in a mat and placed over the foundation  110  so as to be portable. The safety net  104  is then stored in the recess space cavity for deployment. In some portions of the recessed space  109 , a relatively large portion of the safety net  104  may be stored. However, the safety net  104  is preferably distributed relatively uniformly in the recessed spaces  109  over the hard surface  22  to be protected. By achieving a more uniform distribution of the safety net  104  in the recessed spaces  109 , the total distance that they have to travel to reach their designated deployed position is minimized, thereby making it possible to achieve rapid deployment.  
         [0057]     The recessed space  109  may be constructed with any geometrical spatial shape. In general, it is desired that the recessed space  109  to have the smallest possible opening on the surface for minimal surface disturbance but have adequate volume for the storage of the safety net  104  and its easy and rapid deployment, which means minimal contact friction. Since it is preferred that the system be reusable (as opposed to a single use), the surface openings  111   a  must, however, be large enough to allow easy and rapid “fold-back” and storage of the safety net  104  into the recess spaces  109 . Thus, as shown in  FIG. 6 , it is preferred that the recess space  109  taper outward in cross-section away from the surface openings  111   a  towards a wider bottom surface  111   b.    
         [0058]     In one embodiment of the present invention, the springs  108  are distributed more or less uniformly under the entire area of the safety net  104 . At least a portion of the springs  108  are constructed as deployable spring units  200  consisting of one or more elastic elements  201  (one of which is shown in  FIG. 7 ), hereinafter referred to simply as springs, which are preferably tensile or buckling type of springs. Other types of springs, such as those working in bending, torsional or compressive modes may also be used. As would be appreciated by those familiar with the art, springs working with the combination of any number of above modes may also be constructed with or without appropriate linkage, cable and/or other types of mechanisms to perform the required function, i.e., the function of potential energy storage (preloading) and safety net  104  deployment by releasing part or all of the said potential energy. In the schematic drawing of  FIG. 7 , the elastic elements are shown in the deployed position of the safety net  104 .  
         [0059]     Each spring unit  200  is equipped with a preloading mechanism consisting of a mechanism  202  for preloading the springs  201  as the safety nets  104  are pulled into their storage spaces  109 , and a locking mechanism  203  which locks the springs  201  in their desired preloaded position. In one embodiment of the present invention, the preloading mechanism consists of a cable  204 , which is pulled in the direction  205  by an actuator  207  through a pulley system  206  to preload the spring  201  to pull back the safety net  104  into its stored position in the aforementioned recessed spaces  109 . The elastic element  201  and the pulley system  206  are both grounded as shown in  FIG. 7 . In one embodiment of the present invention, the cable  204  is pulled by an electrical motor, which winds the cable over a drum until the safety net  104  is in its fully stored position and a limit switch (not shown) is triggered. In another embodiment of the present invention, the cable  204  is pulled by an air cylinder and its operating valve is switched off when the safety net  104  is at its intended stored position by a similar limit switch (not shown). The locking mechanism  203  is preferably normally locked (by a “braking” spring) and is unlocked only when its unlocking actuation mechanism is energized to deploy the safety net  104 . The locking mechanism  203  may be operated electrically or pneumatically. In general, when the cable  204  is pulled by an electric motor, the locking mechanism  203  is desired to be operated electrically. When the cable  204  is pulled by a pneumatic cylinder, then the locking mechanism  203  is desire to be operated pneumatically. The same is true for the corresponding limit switches. It is obvious to those familiar with the art that the mass of all the moving parts of the spring unit  200  as well as the safety net  104  has to be minimized in order to achieve minimal deployment time as well as to impact load on the athlete during a fall. To achieve minimum mass, the preloading mechanism  202  is preferably constructed by a lightweight tension cable, preferably a high tensile strength woven fabric type.  
         [0060]     The stiffness and the deployed height of the spring elements  201  must be appropriate to ensure that the heaviest athlete falling from the maximum height would not deflect the safety net  104  to the hard surfaces  22  but leave certain distance for the sake of safety. The spring elements  201  may have linear or nonlinear load-deflection characteristics and may be at their free length (no stored potential energy) or with certain level of preloading in their deployed position. In the preferred embodiment of the present invention, the spring elements  201  have nonlinear load-deflection characteristics so that the athlete impact with the safety net is initially softer and as the spring elements are deflected further they exhibit higher stiffness to limit the total free height required under the safety net  104  in its deployed position. The purpose of the initial preloading is to also minimize the total free height that is required under the safety net  104  in its deployed position. The amount of preloading must, however, be limited to limit the maximum impact and resistance force that is imparted on the athlete during a fall to avoid injury. In the schematic drawing of  FIG. 7 , the elastic elements  201  are shown to be deployed in the vertical direction. It is, however, appreciated that the elastic elements  201  may be deployed from any direction and in fact it may be deployed in a bending or torsional modes with or without other assisting linkage or other types of mechanisms.  
         [0061]     In another embodiment of the present invention, the safety net  104  is stored as shown in  FIG. 6 , with its outer edges attached to an enclosing frame  211 , as shown in  FIG. 8 . In its stored position, the safety net  104  and the enclosing frame  211  are both brought down by the deployment mechanism into the recessed spaces  109  (recessed areas are not shown in  FIG. 8  for clarity) in the hard surfaces by the deployable spring units  200 . For relatively small safety nets  104 , the deployable spring units  200  need only be used for the deployment of the frame  211 . Regular elastic elements  201  may, however, still be required to be distributed under the safety net area to provide the desired amount of elasticity adequate for cushioning of a fall. For relatively small safety nets  104 , the deployment of the frame  211  will automatically deploy the safety net  104 . However, for larger safety nets  104 , additional spring units  200  may be used throughout the inner regions of the safety net  104  to prevent the safety net  104  from being pushed to the side or remaining outside the aforementioned recess spaces  109 , above the hard surfaces  22 .  
         [0062]     In yet another embodiment of the present invention, the safety net  104  is stored in the aforementioned recessed spaces  109  of the hard surfaces  22  as shown in  FIG. 6 , with at least two opposing edges of the safety net  104  being attached to two separate cables  220 , which are used to deploy the safety net  104 . The deployed safety net  104  and its deployment cables  220  are schematically shown in  FIG. 9 . The cables  220  are supported by columns  221  and run preferably over pulleys  222  attached to a free end  221   a  of the columns  221 . In its stored position, the safety net  104  and the cables  220  are both stored in the recessed spaces  109  (recessed areas are not shown in  FIG. 9  for clarity) in the hard surfaces  22 . The cables  220  may be pulled down from its deployed (raised) position and kept secure in its stored position by a mechanism such as the spring units  200 , while the cables are released in the direction opposite to the directions  223 . For relatively small safety nets  104 , deployable spring units  200  need only be used on the cables along the edge of the net. Regular elastic elements  201  may, however, be required to be distributed under the safety net area to provide the desired amount of elasticity adequate for cushioning of a fall. Pulling the cables  220  in the direction of the arrows  223  deploys the safety net  104 . For relatively small safety nets  104 , the deployment of the cable  220  will automatically deploy the safety net  104 . However, for larger safety nets  104 , additional spring units  200  may be used throughout the inner regions of the safety net  104  to prevent the safety net  104  from being pushed or remaining outside the aforementioned recess spaces  109 , above the hard surfaces  22 . Alternatively, the cables  220  may be fixed to the free end  221   a  of the support columns  221 . The support columns  221  would then be pulled down into the ground by an actuation mechanism, preferably pneumatic cylinders to store the safety net  104  below the hard surfaces  22  in the recessed spaces  109 . The safety net  104  is then deployed by pushing the support columns  221  out of their stored position and thereby raising the cables  220  and with it the safety net  104 . At least some portions of the cable  220  are preferably elastic to assist in cushioning the fall of an athlete over the safety net  104 .  
         [0063]     In the embodiments shown in  FIGS. 2 and 3 , the safety net(s)  104  are deployed by an actuation mechanism  103 , which operates in a manner similar to that shown in  FIG. 7 . In  FIGS. 2 and 3 , the safety net  104  is shown in its retracted position. It is preferred that the safety net  104  is fixed to a frame  301 , preferably by relatively elastic elements not shown. In  FIG. 10 , the safety net  104  is shown in its deployed position over the hard surfaces  22  that the athlete may fall on. One side  302  of the frame  301 , i.e., the side that deploys towards the vault box area, is preferably elastic to prevent injury in case of impact with a bystander or the athlete. The other three sides of the frame  301  are preferably relatively rigid to allow the safety net  104  to effectively support a load. The deployment mechanism  305  ( 103  in  FIGS. 2 and 3 ) deploys and retracts the frame  301 . In one embodiment of the present invention, the deployment mechanism  305  is constructed with a lightweight cable  304 , which is used to preload an elastic element  306 , preferably by pulling the cable  304  in the direction  307  by an actuator  308 . The actuator  308  may be electrically or pneumatically driven as described for a previous embodiment. A locking mechanism  309  is used to lock the cable  304  to lock the elastic element  306  in its preloaded position. Once the triggering signal is given by the triggering mechanism  102 , the locking mechanism  309  releases the cable  304 , and the potential energy stored in the preloaded elastic element(s)  306  is used to deploy the frame  301  and together with it the safety net  104 . The deployment of the safety net frame  301  may also be assisted by a hanging weight (not shown) and/or an active actuation mechanism (not shown) such as a pneumatic cylinder. In  FIG. 10 , the safety net  104  is shown with dashed lines in its stored position  310 . The safety net  104  is then deployed in the direction  311  to cover the hard surfaces  22 . In the embodiment shown in  FIG. 10 , the safety net  104  is deployed by a pure translational motion in the direction  311 . Alternatively, the safety net may be rotated about a fixed pivot  312 , as shown in  FIG. 11 , in the direction  316 , from its stored position  313  (dashed lines) to its deployed position  314  by the deployment mechanism  305 . Alternatively, the safety net  104  may be brought to its deployed position from its stored position by a combination of translation and rotation by a linkage mechanism  317 , as shown in  FIG. 12 , preferably using a preloaded elastic element similar to that of  305 .  
         [0064]     In the preferred embodiments of this present invention shown in  FIGS. 10-12 , two or more safety nets  104  are employed from opposite sides over the hard surfaces  22  to reduce the time needed for their deployment and to allow the deployment of the safety net around the pole (with the provided recessed area  314  in the safety net  104 ) but very close to it to prevent a falling athlete from going through the opening and hitting the hard surfaces  22 ,  FIG. 11 . The recessed area  314  is provided in all the safety nets  104  that are deployed around the pole area (not shown in other schematics for clarity reasons).  
         [0065]     In another embodiment of the present invention, the frame  301  (with safety net  104  attached thereto) is deployed, preferably by a linkage mechanism  324  from the sides of the running path, as shown in  FIG. 12 . The frame  301  is preferably deployed by the deployment mechanism  305 , i.e., with a preloaded elastic element and its preloading cable and actuation and locking mechanisms as was described for the previous embodiments of the present invention. In the schematic of  FIG. 12 , a planar four-bar linkage mechanism  324  is used to achieve the motion to deploy the frame  301 . The four-bar linkage mechanism  324  has links  317  and  318  with grounded rotating joints  319  and  320 . The side  321  of the frame  301  is the coupler link of the four-bar linkage mechanism  324 . In  FIG. 12 , the frame  301  is shown in its stored position (solid lines) with the linkage mechanism  324 , in an intermediate position  322  and its fully deployed position  323 . The safety net  104  is not shown in the frame of  FIG. 12  for clarity.  
         [0066]     In the schematic of  FIG. 12 , the simple planar four-bar linkage mechanism  324  is shown for achieving the aforementioned deployment motion. However, numerous other planar or spatial types of linkage mechanisms, which are well known in the art, may be used to achieve similar motions, which provide, for example, for faster and smoother deployment. In addition, the four-bar linkage mechanism  324  has one degree-of-freedom and is considered to be constructed with relatively rigid links and joints. However, linkage mechanisms with more than one degree-of-freedom may also be used. Alternatively, linkage mechanisms with relatively flexible links and living joints may also be used to construct the deployment mechanisms and achieve similar deployment motions. The more flexible mechanisms with more degrees-of-freedom would generally provide lighter deployment mechanisms and could be used to achieve faster and smoother deployment motion.  
         [0067]     Another embodiment of the present invention is shown in  FIG. 13 . In the schematic of  FIG. 13 , a view of the running path  325  and the safety net  104  attached to a frame  301  is shown looking in the running direction, towards the bar posts. Therefore in the view of  FIG. 13 , only the proximal edge of the safety net frame  301  is visible. In the present embodiment, the safety net frame  301  is deployed by one or more linkage mechanisms  330 . The deployment linkage mechanism  330  shown in  FIG. 13  consists of one or more planar linkage mechanisms, which are positioned along the length of the frame  301  (only one such mechanism is seen in the view shown in  FIG. 13 ). In its stored position  334 , the frame  301  is positioned away from the running path  325 , preferably at an angle  331 . In the stored position  334 , the center of mass  332  of the frame  301  and all its associated moving parts are preferably positioned at a height  333  above the ground (hard) surfaces  22  to be covered. The height  333  is preferably close to the height that the center of mass  332  assumes in its deployed position  335 . The purpose of keeping the center of mass  332  at nearly a level height is to minimize the amount of energy that is required to deploy the frame  301  and attached safety net  104  from its stored position  334 . It is appreciated by those familiar with the art that that the angle  331  and the height  333  that the center of mass  332  assumes in its stored position  334  can be calculated to achieve a fast and smooth deployment with relatively small electric or pneumatic actuation devices.  
         [0068]     The linkage mechanisms  330  deploys the frame  301  by rotating and translating it without tilting it in its longitudinal direction from its stored position  334  to its deployed position  335 , through intermediate positions  336  and  337 . The frame  301  is preferably deployed by the deployment mechanism  305  discussed above, i.e., with a preloaded elastic element and its preloading cable and actuation and locking mechanisms as was described for the previous embodiments of the present invention. In the schematic of  FIG. 13 , the linkage mechanism  330  is a planar four-bar linkage mechanism, which is used to achieve the aforementioned deploying motion of the frame  301 . The four-bar linkage mechanism  330  has links  338  and  339  with grounded rotating joints  340  and  341 . The visible side of the frame  301  is the coupler link of the four-bar linkage mechanism  330 .  
         [0069]     In the schematic of  FIG. 13 , the simple planar four-bar linkage mechanism  330  is used for achieving the aforementioned safety net deployment motion. However, numerous other planar or spatial types of linkage mechanisms, which are well known in the art, may be used to achieve similar motions, which provide, for example, for faster and smoother deployment. One particular variation of the four-bar linkage mechanism which may be used is a parallelogram mechanism in which the coupler link is the safety net frame  301 , which can be used to deploy the safety net frame  301  with a motion that keeps the safety net  104  parallel to the ground (running path) at all times. In addition, the four-bar linkage mechanism  330  has one degree-of-freedom and is considered to be constructed with relatively rigid links and joints. However, linkage mechanisms with more than one degree-of-freedom may also be used. Alternatively, linkage mechanisms with relatively flexible links and living joints may also be used to construct the deployment mechanisms and achieve similar deployment motions. The more flexible mechanisms with more degrees-of-freedom would generally provide lighter deployment mechanisms, thereby making it possible to achieve faster and smoother deployment motion. Alternatively, different linkage or other types of mechanisms may be used to start the deployment of the frame  301  from some arbitrary stored position and bring it to the deployed position  335  using any arbitrary motions suitable for each particular application. Different deployment speeds and motions may be desired for different types of trainings and different levels of athlete competency.  
         [0070]     Alternatively, a deployment linkage mechanism may be constructed which is a combination of the mechanisms shown in  FIGS. 11 and 13 , or a combination of those in  FIGS. 12 and 13 , as they are placed in series. The linkage mechanism shown in  FIG. 13  may also be used to achieve the parallel motion of the safety net frame  311  shown in  FIG. 10 .  
         [0071]     Another embodiment of the present invention is shown in  FIG. 14 . In the schematic of  FIG. 14 , a view in the running direction  325  similar to that of  FIG. 13  is shown. The safety net frame  301  is stored prior to deployment in position  350 . In this embodiment, one side of the safety net frame  301  is fixed to the ground  352  (preferably a post, not shown) by at least one cable  351 . The opposite side of the safety net frame  301  is attached to one or more cables marked  353  and  354 . In its stored position, the segment  353  of this cable is stored in the recessed spaces  109  provided in the hard surfaces  22  (not shown). The segment  354  is passed over the pulley  355 , which is fixed to the ground  356 , preferably a post (not shown).  
         [0072]     The frame  301  is preferably deployed by a deployment mechanism  361 , which is very similar to that of deployment mechanism  305  discussed above. In the deployment mechanism  361 , an elastic element  362  is preloaded by pulling the cable  363  by an electric or pneumatic actuation mechanism  308  as previously described for the embodiment of  FIG. 10 . During preloading, the segment of the cable  354  is locked in place by the locking (braking) mechanism  309  ( FIG. 10 ), positioned just past the pulley  355  (not shown in  FIG. 14 ). Once a deployment signal is received from the triggering mechanism and deployment control unit  102 , the braking mechanism  309  is released, and the cable segment  354  is pulled over the pulley  355  in the direction  357  by the preloaded spring alone or by the preloaded spring together with the actuator  308 , thereby moving the safety net frame  301  in its deployed position  358  over the hard surfaces  22  to be covered. In the deployed position  358  of the safety net frame  301 , the cable segments  351  and  353  are be in positions  359  and  360 , respectively. In this embodiment, the cable segments  359  and  360  may be relatively elastic to provide for additional cushioning of a fall over the safety net  104 . In the preferred implementation of this embodiment, a second safety net frame is symmetrically positioned on the opposite (right side,  FIG. 14 ) of the running path similar to that shown in  FIGS. 11 and 12 .  
         [0073]     In yet another embodiment of the present invention, the cable segments  351  or  354  are replaced by one of the linkage mechanisms of the previous embodiments shown in  FIGS. 11-13 . The preferred combination is the one, which is constructed by the linkage mechanism  330  on one side of the safety net frame  301  as shown in  FIG. 13 , and with the cable segments  353  and  354 , together with the pulley  355  and the deployment mechanism  361  on the running path  325  side of the safety net frame  301 .  
         [0074]     In yet another embodiment of the present invention, a combination of sidewise deploying safety nets,  FIGS. 10-14 , and embedded safety nets,  FIGS. 4-9 , may be used. The purpose of such combinations may be to provide for higher reliability by providing for the deployment of more than one safety medium; it might be to provide for a more gradual resistance to fall (for example, the first barrier may be softer and the second one more stiff); it might be for the purpose of making each barrier and its components lighter, thereby making it possible to be deployed faster; or for two or more or these reasons. In addition, the deployment of the different safety nets  104  may be triggered by different sensors and when different events are detected, thereby providing for the best possible protection against each particular fall.  
         [0075]     In yet another embodiment of the present invention, preloaded deployable fall cushioning units  400  are distributed over the hard surface areas  22 , as shown in  FIG. 15 . The cushioning units  400  are embedded in spaces  401  provided in the hard surface areas as shown in the cross sectional view  16 - 16  in  FIG. 16 ). In their retracted position as shown in  FIG. 16 , the top surface  402  of the cushioning units  400  provide a relatively rigid surface to render the running areas hard and appropriate for pole vaulting. However, in their deployed position, the fall cushioning units  400  substantially cover the hard surfaces  22 , provide a relatively soft impact surfaces for a falling athlete, and provide the required axial flexibility characteristics to lower the impact forces to levels that prevent serious injury to the falling athlete.  
         [0076]     The schematic of one embodiment of the cushioning unit  400  is shown in  FIG. 17 . The unit consists of a top  402 , details of which is described below, an elastic element  403 , which in its preloaded position brings the unit in its retracted position as shown in  FIG. 16 . The elastic element  403  not only serves as a fall cushioning element but also for fast deployment of the unit  400 . The preloading of the elastic element  403  and the retraction of the top surface  402  are achieved by the preloading mechanism  202  and are similarly triggered for deployment both as described above with regard to the embodiment of  FIG. 7 .  
         [0077]     In  FIG. 17 , for the sake of simplicity, the top piece  402  of the cushioning unit  400  is shown as it is in the retracted position of the cushioning unit ( FIG. 16 ), in which case, it exhibits fairly rigid characteristics to the application of load on its top surface as the athlete steps on its surface. The load exerted by the athlete&#39;s foot on the top surface of the top piece  402  is primarily compressive,  404 , with a smaller shearing force  405  ( FIG. 16 ). In one embodiment of this invention, the top piece is constructed with one or more “leaves”  406  that are attached to the surfaces of  401  by hinges  407 , and are biased by springs (not shown) to stay closed while the cushioning units  400  are in their retracted position. During the deployment of the units  400 , the leaves  406  are forced open by the elastic element  403  as the unit is deployed from its retracted position  410  to its deployed position  411 . The schematic of  FIG. 18  shows a two leaf  406  design in closed (retracted) position and open (deployed) position  408  of the cushioning unit  400 .  
         [0078]     In another embodiment of cushioning unit  400 , the unit is constructed with elastic balloon like actuators  415 , which are extended (deployed) by pressurized air or gas, position  418 , the schematic of which is shown in  FIG. 19 . The top portion  416  of the balloons  415  is preferably made to expand laterally as the cushioning unit is deployed to cover the hard surfaces  22  completely and not allow a falling athlete to pass between adjacent balloons  415 . This is accomplished by making the top portion  416  with thinner and thereby more extensible materials than the remaining lower portion of  415 . As a result, as the balloon  415  is pressurized during deployment, the top portion  416  is expanded further to form a larger shape volume, with preferably nearly square surfaces to better cover the hard surfaces. Another method of enlarging the top portion  416  during deployment is to construct this portion with pleated elastic material that “collapse” inward as the balloon  415  is depressurized.  
         [0079]     In another embodiment of the cushioning units  400 , adjacent balloons  415  are connected together by relatively elastic elements  417  to further prevent them from separating during a fall, as shown in  FIG. 20 . The elastic elements  417  are stored in recessed spaces  111  in the hard surfaces  22  while the cushioning units  400  are in retracted position.  
         [0080]     In another embodiment, the top portions are airbags  419 , which are deployed once the balloon like actuators  415  are deployed, as shown in  FIG. 21 . The airbags  419  are preferably stored in internal cavities  420  within the lower portion  421  of the actuators  415 , and deploy up and out as the balloon actuators  415  are pressurized. The cavity  420  is preferably “cup” shaped to allow the airbag  419  to be readily deployed.  
         [0081]     Referring now to  FIG. 22 , in yet another embodiment of the cushioning unit  400 , the top portion of the elastic element  403  or the top portion  416  of the balloon like actuator is made from pieces of soft sponge type of material  422  that “bloom out” to cover the hard surfaces  22  as the cushioning units  400  are deployed.  
         [0082]     In the aforementioned embodiments, the term safety net  104  is used to indicate the barrier material that is deployed above the surfaces over which an athlete may fall in a way that can cause injury, particularly a serious injury. The barrier material may actually be a net or loosely woven material or a solid film-like or woven material, such as a spandex type material. Part or all the materials used to fabricate the barrier material may be substantially elastic. The material may also be fabricated with such patterns and with one or more basic materials to achieve the desirable mechanical response characteristics suitable for the present application, i.e., to provide the required cushioning effect during a fall. The optimal mechanical response characteristic for a barrier material is that would provide relatively small resistance during initial, small area contact, such as during contact with the head in a fall on the head or a fall on one foot. The barrier material resistance should then gradually increase to its maximum as a larger portion of the body comes in contact with the barrier material. In general, the optimal mechanical response characteristic of the safety net is obtained by the combination of the mechanical response characteristics of the barrier material and all the other components of the safety net such as the frame, the elements connecting the barrier material to the frame, the cables and linkage and other types of mechanisms of the deployment mechanism, the preloading elastic elements, the braking (locking) elements, the connecting posts, ground connections, etc., that are used in the construction of the safety net system.  
         [0083]     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.

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