Patent Abstract:
Motion or velocity stilts are provided a strapping system for attachment of the leg and foot of a user. An upper knee cuff uses dual straps that enwrap the leg and are secured by a front buckle and perimeter lengths of hook and loop fasteners. The hook and loop fasteners enable fore and aft leg positioning adjustments. The upper cuff is attached to the spring support utilizing a pair of knee braces that permit pivoting of the knee cuff as well as width adjustment for variation in user knee and leg diameters. The lower strapping system utilizes separate heel, instep, and toe straps to secure the foot to a foot plate.

Full Description:
RELATED APPLICATIONS 
     The present application claims priority under 35 USC §119(e) to U.S. Provisional Patent Application Ser. No. 60/979,038, filed on Oct. 10, 2007, which is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to spring or motion stilts, and, more particularly, to improved knee and foot retention systems thereon. 
     2. Description of the Related Art 
     The VELOCITY™ brand motion stilts are the supreme “performers” of inertia stilts. Motion stilts were originally designed with Military applications in mind. In a test for the United States Air Force in 2004, a quad was chased for ¼ of a mile at a sustained pace of 23 mph. A vertical jump of 10 feet was obtained with these motion stilts, which were specially-designed for the Air Force. 
     The VELOCITY™ brand motion stilts are for the serious stiltwalker acrobat. These motion stilts are adjustable in every direction, designed for multiple users, have removable, washable parts, tracking knee cuff for comfort and quick release buckles for quick in and out changes. The rubber footings durometer that is, the “grip” provided by the rubber footing, can be custom made to order, with options in the form of spikes for grass or ice and custom boot configurations. The VELOCITY™ brand motion stilts can generate up to 900 lb/sq. inch of pressure and weigh approximately 5.5 lbs (total). 
     Certain features provide additional advantages, specifically the split knee attachment and the foot/bottom strapping system. 
     DISCLOSURE OF THE INVENTION 
     The Split Knee Bow™ provides for enhanced adjustability—both forward and backward. If there is a preferred foot location or if there is a desired height that is extremely low, the soft cuff material can be easily modified and re-attached using the hook and loop fastening system, re-configuring the upper shin restraint so the person&#39;s leg will not touch the back of the top spring capture. 
     Adjustability is also provided for the preference in leg cuff width. If someone of a sizeable leg or, alternatively, a slender leg, needs a snug fit, only the Split Knee Bow™ retention system will allow the adjustability associated with this need. The bows can be adjusted inwards or outwards to obtain the perfect fit. 
     The Split Knee Bow™ cuff system also tracks the action of the leg by the use of mechanical grade Teflon® bushings and an axle system that locks it to the aluminum side bars 
     Versatility is provided, where the top cuff has a Velcro® pad inside of laminated foam and is durable enough for removal and laundry. Also, where there are multiple users, each artist can have his or her own set of removable pads. 
     Bottom straps for adjustability have been designed to accommodate just about every size and style of shoe. The heel can be adjusted so that a small shoe can be moved forward for a safer strap and the upper cuff can be moved congruently to keep alignment. For a long shoe the heel can be moved all the way back and typically with the upper cuff. There is no left or right. 
     The artist will not have a solid knee bow, aluminum pipe, rubbing against the knee cap for discomfort or injury. The knee bow holds the leg tight and snug to avoid slipping around. The cuff tracks the legs movement still maintaining the division of the lateral force between the two bars. The quick-release buckles or 2-pass buckles allow the artist to remove the calf cuff almost instantly. Such quick release capabilities enable quick changes in costume, prompt removal if injury occurs or for similar situations and needs. 
     The custom footing comes in a custom-poured durometer, according to what is needed. Where required, a friction additive can be included in the poured material. Cleat bottoms allow for running and bouncing on grassy surfaces or on ice and areas not commonly safe for the normal rubber footing. The standard footing is a thinner 80 durometer rubber. Rollerblade options may also be used, and adapt to the footing to allow for inline skating with better leverage in the stroke. 
     In a further aspect of the present invention a motion stilt comprising: a spring support comprising: a central spring having a first terminus and a second terminus, a lower spring capture attached to said central spring at said first terminus, and an upper spring capture attached to said central spring at said second terminus; a knee cuff rotationally attached to said upper spring capture; and a foot plate having a heel and a toe end, said heel end of said foot plate attached to said upper spring capture and said toe end pivotally attached to said lower spring capture. 
     It is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components described hereinafter and illustrated in the drawing figures. Those skilled in the art will recognize that various modifications can be made without departing from the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a motion stilt in accordance with the present invention. 
         FIG. 2  is a partial perspective view of a split knee bow belt upper attachment system on a motion stilt in a closed configuration. 
         FIG. 3  is a partial perspective view, similar to  FIG. 2 , of a split knee bow belt attachment system in an opened configuration. 
         FIG. 4  is a top plan view of a split knee bow belt attachment system in a partially open configuration. 
         FIG. 5  is a partial perspective view of a reinforce belt end section. 
         FIG. 6  is a partial perspective view, with portions broken away, of a foot strapping system in accordance with the present invention. 
         FIG. 7  is a partial side elevation view of a toe strap attachment system in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The leg strapping system is used to attach the leg and foot to the stilt. This strapping system utilizes military spec webbing and buckles. This system permits a user to quickly engage with and disengage from the stilts without compromising the integrity of the strapping system materials. 
     Reference is now made to the drawings wherein like numerals refer to like parts throughout. In  FIG. 1 , a motion or spring stilt  10  is shown, having a spring support extending from a knee cuff  18  to a footing  22 . The spring support  14  is a multi-component member consisting of a central spring  24  that extends between a lower spring capture  26  and an upper spring capture  28 . The upper and lower spring captures 26, 28 are rigidly attached to the central spring  24  in a manner creating a solid member that efficiently transmits flexing loads to the footing  22  as the central spring  24  flexes in response to varying loads applied by a user (not shown in the drawings). 
     The knee cuff  18  and a foot plate  32  define the points of interconnection between the user and the motion stilts  10 . A pair of rocker arms  34   a ,  34   b  connect the foot plate  32  to the lower spring capture  28 , utilizing a rocker arm axle  36  to permit relative rotational motion therebetween as required by the flexure of the spring support  14 . 
     A vertical upright  42  connects the rear of the foot plate  32  to the upper spring capture  28 , with a vertical upright axle  44  at the connection with the foot plate  32  to permit relative rotational movement between the foot plate  32  and the vertical upright  42 . A pair of leveling rods  48  are attached to and extend between an upper section of the vertical upright  42  and a mid-section of the foot plate  32 , enabling adjustment of the foot plate  32  in a horizontal plane. 
     A plurality of leg brace brackets  52  are utilized to attach a pair of leg braces  54  to the vertical upright  42 . The knee cuff  18  is rotatably attached to and supported by each of the pair of leg braces  54 , utilizing a pair of knee cuff axle connectors  56  located on each side of the knee cuff  18 . 
     A series of retention straps are used to releasably attach the foot of the user to the foot plate  32 , including a heel strap  62 , an instep strap  64 , and a toe strap  66 . A toe support plate  68  is attached to the forward section of the foot plate  32 , providing a broader support surface for the user. 
     A footpad support  72  is formed on the bottom surface of the lower spring capture  26 , and a variety of gripping surfaces  74  may be attached thereto—a flat pad is shown in  FIG. 1 ; however, other options such as spikes for grass and ice, and specialized connectors such as for use with in-line skates are considered as encompassed by the present invention. 
     As is shown in  FIG. 2 , the upper knee cuff  18  is held together primarily by a pair of dual Velcro® straps  78  that are preferably four (4) inches wide in the rear for adjustability. Such adjustability permits a user to move his or her leg forward or backward within the stilt attachment location to achieve a desired lower leg and foot placement. 
     A cuff pad  82  is received within the leg-receiving opening defined by the dual straps  78 , and is preferably held in place using hook and loop fasteners, such as one surface formed on the inside surface of the dual straps  78  and a complementary surface formed on the outer surface of the cuff pad  82 . Including a laminated foam layer, the cuff pad  82  may be removed for laundry or for replacement where there are multiple users of the motion stilts  10 . 
     The front portion of the dual straps  78  is attached by means of a buckle  84  (such as an Austrian buckle used in the military that has a 4000-pound breaking strength). The buckle  82  must have both ears (flanges of the opening device) depressed in order for the buckle to disengage. 
     The knee cuff axle connectors  56  retain the upper knee cuff  18  onto the Split Knee Bow™ system, which is unique to VELOCITY™ brand motion stilts, by preferably utilizing ¼-inch by 20 grade 8-rated bolts, as well as utilizing mechanical grade Teflon® bushings. A fender washer  86  of ¼-inch are used to connect the dual straps  78  to the leg braces  54 , providing a greater surface area over which the forces are transmitted between the motion stilts  10  and the attachment location of the knee cuff  18 . 
     As is best shown in  FIG. 3 , a shank  88  of each of the bolts functions as an axle, permitting the knee cuff  18  to pivot about each of its connections to the leg braces  54 . This pivoting action—also unique to the VELOCITY™ brand motion stilts, is another safety feature. The pivoting allows the knee cuff  18  to track the leg as opposed to forcing the kneecap into a standard position, with all of the give taken on or by the knee or by the surrounding area of the body. 
     The dual straps  78  are shown in  FIG. 3  as consisting of an inner strap  92  and an outer strap  94 —each attached to a separate knee cuff axle connector  56 . The inner and outer straps  92 ,  94  are attached utilizing complementary surfaces of hook and loop fasteners in the rear portions as well as the knee cuff buckle  84  in the front. In a presently preferred embodiment a DELRIN® stiffener is inserted between the double strap layers, and is also preferably curvilinear in shape to maintain the dual straps in proper strap-configuration, resisting a tendency for the straps to turn over at the edges, gradually forming rope-like shapes. 
     Turning to  FIG. 4 , the Split Knee Bow™ leg retention system, formed by the knee cuff  18  and the pair of leg braces  54 , is adjustable utilizing the pair of leg brace brackets  52  for wider or narrower legs and calf muscles—this is also unique to the VELOCITY® brand motion stilts. As is also shown in  FIG. 4 , both the inner strap  92  and the outer strap  94  are provided a double-layer construction adjacent their connection to the respective leg braces  54  and along their length of inter-engagement with one another to form the rear of the knee cuff  18 . 
     The lower strapping system for the motion stilts  10  consists of the three separate straps: the instep strap  64 , the heel strap  62 , and the toe strap  66 . As is shown in  FIG. 6  the instep strap  64  is a two-piece strap  64   a ,  64   b  retention system that is locked into place by Velcro® brand hook and loop fasteners—with complementary lengths of each formed on the separate straps  64   a ,  64   b  forming their cooperative attachment. One end of each of the instep straps  64   a ,  64   b  is attached to the foot plate utilizing a retaining bolt  96 —preferably grade 8 bolts as well as Teflon® bushings to permit unrestrained rotation. 
     The bolted ends of the instep straps  64   a ,  64   b  are preferably provided Spectra Shield® composite material  98  that is sewn into the folds of the military spec webbing to provide increased strength at this important connection (see  FIG. 5 ). Spectra Shield® composite material is the strongest commercial-grade fabric in the world. The longer of the instep strap ends  102  has Velcro® sewn to the top, both hook and loop, and that piece is looped through a shorter end that has a stainless turn-around bar (not shown). After the longer end  102  turns around, it then utilizes the Velcro® fasteners to attach to itself on the loop end. 
     Returning again to  FIG. 6 , the heel straps  62  are cut to be attached beneath the toe support  68  so that weight, friction, and gravity all play a role in attachment strength, in addition to use of a foot plate retention bolt  106 . The retention bolt  106  and associated nut get glued-on the threads when installed for further insurance that the ends of the heel straps  62  will not separate from the toe support  68  during use of the motion stilts  10 . The back of the heel strap also has Velcro® for adjustability. 
     The toe strap  66  is attached to the stilts beneath the toe support  68  for the same reasons of securement as was the case with the heel strap  62 . The toe strap  66  has a turn-around bar  108  on one side and an adjustable, 2-pass buckle  112  on the other side for adjustability. Also shown in  FIG. 7  is the leveling rod base  116 , to which are attached the pair of leveling rods  48 . In this manner the leveling rods  48  permit adjustability of the foot plate  32  through their attachment to and into the leveling rod base  116 . 
     My invention has been disclosed in terms of a preferred embodiment thereof, which provides a motion stilts retention system that is of great novelty and utility. Various changes, modifications, and alterations in the teachings of the present invention may be contemplated by those skilled in the art without departing from the intended spirit and scope thereof. It is intended that the present invention encompass such changes and modifications.

Technology Classification (CPC): 0