Abstract:
A trampoline board includes a resilient body with a foam core. At least one flex zone (e.g., a channel) which acts as a living hinge extends from a first lateral edge to a second lateral edge to facilitate bending to conform to the shape of a depressed trampoline surface. Sandal-like trampoline board bindings are threadedly coupled to inserts molded into the resilient body. Each binding includes a shock absorbing midsole and is devoid of any potentially harmful structures that extend above the ankle of a user, such as the molded support behind the heel characteristic of snowboard bindings. Adjustable cushioned straps secure the sandal-like trampoline board bindings to a user&#39;s feet. The insert pack includes a base with a plurality of parallel threaded shanks extending perpendicularly therefrom.

Description:
FIELD OF THE INVENTION 
     This invention generally relates to trampoline boards, and more particularly, to a resilient stable trampoline board adapted to bend and conform to the contour of a deflected trampoline during a downward landing, return to and maintain a substantially undeflected stable configuration upon rebound and during airborne maneuvers, and provide low profile adjustable bindings suitable for use without boots. 
     BACKGROUND 
     For many years, water and snow sport enthusiasts honed their aerial skills by practicing on a trampoline with a board attached to their feet. Illustratively, an article in the Aug. 31, 1997 edition of The Denver Post, DENVER &amp; THE WEST; Pg. B-06, illustrates and explains that “Fuzz Federson . . . of the U.S. Freestyle Ski Team does some snowboard moves from a trampoline Saturday as he and other members of the team helped entertain people in the long lines, above, that formed outside Gart Bros. sporting goods store at East 10th Avenue and Broadway . . . . ” Similar public trampoline performances using snowboards with snowboard bindings are reported in the Jun. 11, 1997 edition of the Hobart Mercury (Australia), “A few experts . . . demonstrated what they could do with a snowboard and trampoline in a crowded Elizabeth Mall in Hobart yesterday;” as well as in a Jan. 14, 1997 PR Newswire article reporting that Three Time World Freestyle Skiing Champion, Trace “The Ace” Worthington will make personal appearances and perform his ski and snowboard trampoline show at Tommy Hilfiger New Generation shops across the country. Likewise, a Jan. 1, 1997 article in the Washing Post, Prince William Extra; Pg. V08, entitled A New Twist for Snowboarding Enthusiasts; Local Gym, Stores Provide Resources To Learn About Sport explains “ . . . that&#39;s exactly what some local snowboard enthusiasts are doing these days at the gymnastics club on Morse Lane, using a large trampoline to practice complicated moves. The string-bed netting, after all, is a lot softer on the backside than frozen ground.” 
     As the use of boards on a trampoline has gained popularity, various trampoline boards have been devised. After all, snow boards and wakeboards are expensive, may damage a trampoline surface, may become damaged on springs and frames of a trampoline or by falling off a trampoline, tend to slip on a trampoline surface, and may injure a user. Alternative boards include various soft-sided board-like structures that will not damage the trampoline or injure the user, but suffer other shortcomings. 
     Many conventional foam boards lack sufficient rigidity to provide a realistic training experience. In use, the board loses stability (i.e., flops around) when airborne, which interferes with training because it does not realistically simulate the feel of maneuvering a snowboard, wakeboard or skateboard. Upon landing on a trampoline under the weight of a user, the foam becomes substantially compressed and provides an insubstantial substrate for propelling the user upwardly or compensating for a skewed landing. 
     When conventional boards (e.g., snowboards, skateboards and wakeboards) are used on trampolines, they do not flex sufficiently to conform to the trampoline surface during jumps, which tends to dampen the bounce of the board off the trampoline. The dampening effect limits the maximum jump height achieved, affecting the user&#39;s ability to execute training maneuvers properly. Additionally, even if the edges of the board may be covered, the hard surface of the board poses a risk to users. 
     U.S. Pat. No. 6,196,558 to Simon discloses a board referred to as a footboard with straps through holes or snowboard bindings to secure the footboard to a user&#39;s feet. Simon discloses a limited range of materials for the footboard composition, including wood (e.g., plywood), fiberglass, plastic, carbon fiber, aluminum, and other similar materials, or composites of such materials. Straps through holes do not provide a secure means for binding, nor do they emulate the bindings of conventional boards. Snowboard bindings are undesirable because such bindings are designed to accommodate bulky boots not worn during trampboarding. Additionally, snowboard bindings feature a stiff molded support behind the heel and up the calf area to allow riders to apply pressure and effect a “heelside” turn on the slopes. Unfortunately, however, the molded support is conducive to injury by digging into the user&#39;s legs and derriere during trampoline use. 
     Accordingly, a need exists for a resilient stable trampoline board adapted to configured to bend and conform to a deflected trampoline during downward motion and return to and maintain a substantially undeflected configuration during airborne maneuvers. The invention is directed to overcoming one or more of the problems and achieving one or more of the advantages as set forth above. 
     SUMMARY OF THE INVENTION 
     In one exemplary embodiment of a trampoline board according to principles of the invention, a resilient body with a foam core is provided. The resilient body resembles a sports board such as a wakeboard, snowboard, skateboard or other sports board. The resilient body is sized to attach two feet of a user. The resilient body includes top and bottom surfaces, a tip and a tail, and first and second lateral edges, the top surface including at least one flex zone (e.g., a channel) extending from the first lateral edge to the second lateral edge, said at least one channel facilitating bending of the board to conform to the shape of a depressed trampoline surface. At least one furrow may be provided along a portion of the first lateral edge and at least one furrow may be provided along a portion of the second lateral edge. A plurality of parallel channels, each extending from the first lateral edge to the second lateral edge, and each facilitating bending and conformity to a trampoline surface may be provided. The channels act as living hinges. 
     Flex zones are portions of reduced thickness (i.e., thickness measured from top surface to bottom surface) at locations on the board (e.g., the midline between tip and tail) where flexibility is desired to easily conform to the deformed surface of a trampoline under tension. The flex zones facilitate controlled bending. Concomitantly, the board is resilient, returning to its unbent configuration upon rebound, without fluttering while airborne. 
     In another aspect of an exemplary embodiment of the invention, trampoline board bindings are threadedly coupled to the resilient body and configured to receive a left foot and right foot of a user and secure the user&#39;s left and right feet to the trampoline board. The bindings are sandal-like structures being sized and configured to accommodate bare feet, but may also accommodate feet in socks or street footwear. They do not accommodate snow boots. Each binding includes a sole comprising an insole that contacts a user&#39;s foot, an outsole that contacts the top surface of the resilient body of the trampoline board, and a shock absorbing midsole. The bindings are devoid of any structure that extends above the ankle of a user, such as the molded support behind the heel characteristic of snowboard bindings. The bindings further include at least one cushioned adjustable strap passing over an instep and at least one cushioned adjustable strap passing around a heel and/or ankle. 
     In another aspect of an exemplary embodiment of the invention, an insert pack is molded into the resilient body of the trampoline board and configured to threadedly couple the resilient body to trampoline board bindings configured to receive a left foot and right foot of a user and secure the user&#39;s left and right feet to the trampoline board. The insert pack includes a base with a plurality of parallel threaded shanks extending perpendicularly therefrom. The shanks have a free end extending to the deck. The base is molded into the body between the top and bottom surfaces. The bindings including means (e.g., screws or other threaded couplings) for threadedly engaging threaded shanks of said insert pack. The insert pack may comprise separate components, one for the left foot binding and one for the right foot binding, or may comprise an integrated elongated unit with an intermediate stiffening joint. 
     In another aspect of an exemplary embodiment of the invention, an elongated resilient stringer may molded into the body parallel to the centerline along the longitudinal axis from tip to tail and between the first and second lateral edges of the resilient body of the trampoline board. The stringer may be perforated to improve adhesion. 
     In another aspect of an exemplary embodiment of the invention, the foam core is ethylene vinyl acetate (EVA), high-rebound polyurethane (HRPU), or polyethylene. The top and bottom surfaces are skins comprising high density polyethylene (HDPE), extruded polyurethane, or a spandex fabric with an extruded polyurethane exterior sheet heat laminated to the spandex fabric and forming an outer layer of the top surface. An anti-slip pad may also be attached to the bottom surface of the body of the trampoline board. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other aspects, objects, features and advantages of the invention will become better understood with reference to the following description, appended claims, and accompanying drawings, where: 
         FIG. 1  is a plan view of an exemplary trampoline board in accordance with principles of the invention; and 
         FIG. 2  is a profile view of an exemplary trampoline board in accordance with principles of the invention; and 
         FIG. 3  is a perspective view of an exemplary trampoline board in accordance with principles of the invention; and 
         FIG. 4  is a cross section (A-A) view of an exemplary trampoline board in accordance with principles of the invention; and 
         FIG. 5  is a perspective view of an exemplary trampoline board with bindings in accordance with principles of the invention; and 
         FIG. 6  is a perspective view of an exemplary foot binding for a trampoline board in accordance with principles of the invention; and 
         FIG. 7  is a plan view of an alternative exemplary trampoline board in accordance with principles of the invention; and 
         FIG. 8  is a perspective view of an alternative exemplary trampoline board with bindings in accordance with principles of the invention; and 
         FIG. 9  is a first perspective view of an exemplary insert pack for bindings for a trampoline board in accordance with principles of the invention; and 
         FIG. 10  is a second perspective view of the exemplary insert pack for bindings for a trampoline board in accordance with principles of the invention; and 
         FIG. 11  is a perspective view of an exemplary unitary insert pack with a stiffening joint for bindings for a trampoline board in accordance with principles of the invention; and 
         FIG. 12  is a cross section (B-B) view of an exemplary insert pack molded in a trampoline board in accordance with principles of the invention; and 
         FIG. 13  is a cross section (B-B) view of an exemplary insert pack molded in an alternative trampoline board in accordance with principles of the invention; and 
         FIG. 14  is a bottom perspective view of an exemplary trampoline board in accordance with principles of the invention; and 
         FIG. 15  is a perspective view of a trampoline and an exemplary trampoline board in a bent configuration conforming to the deformed surface of the trampoline in accordance with principles of the invention and 
         FIG. 16  is a perspective view of an alternative exemplary trampoline board in accordance with principles of the invention. 
     
    
    
     Those skilled in the art will appreciate that the invention is not limited to the exemplary embodiments depicted in the figures or the shapes, relative sizes, proportions or materials shown in the figures. 
     DETAILED DESCRIPTION 
     A trampoline board (i.e., board) according to one embodiment of the present invention is shown in  FIGS. 1 ,  2  and  3 , generally indicated at  100 . The body  110  of the board  100  includes top  205  and bottom  210  surfaces and a tip  215  and a tail  220 . The top surface  205  (also known as the deck) of the trampoline board includes a plurality of furrows  115 ,  125 ,  135 ,  145 ,  165 ,  170 ,  175 ,  180  along the lateral edges  107 ,  109 , as well as furrows  155 ,  195  along the tail  220  and tip  215 , to facilitate gripping. These furrows are also known as grab rails. In addition to providing a gripping surface, the grab rails enhance stiffness through corrugation. A plurality of channels  120 ,  130 ,  140 ,  150  and  185  (e.g., generally v- or u-shaped furrows) extend from one lateral edge  107  to the opposite lateral edge  109 . The lateral edges  107 ,  109  are also known as rails. The channels  120 ,  130 ,  140 ,  150  and  185 , which facilitate bending (i.e., folding) of the board  100  during use by serving as a living hinge or a joint more easily bendable than portions of the body  110  without the channels, are each a type of “flex zone” as described herein. Profile views of these channels  120 ,  130 ,  140 ,  150  and  185  are provided in the cross-section view A-A of  FIG. 4 . 
     Flex zones are portions of reduced thickness (i.e., thickness measured from top surface to bottom surface) at locations on the board (e.g., the midline between tip and tail) where flexibility is desired to easily conform to the deformed surface of a trampoline under tension. Flex zones act as living hinges, which facilitate controlled bending (i.e., bending during impact with a trampoline surface to conform to the shape of the trampoline surface as it deflects). Concomitantly, the board is resilient, returning to its unbent configuration upon rebound, without fluttering (i.e., rapid and repeated up and down movement of the tip and tail) while airborne. Fluttering is avoided by providing sufficient rigidity to avoid substantial vibratory motion, such as by providing a sufficiently high modulus of elasticity and one or more constraining inserts. 
     Referring now to  FIGS. 5 and 6 , exemplary bindings  600   605  are shown. Bindings  600 ,  605  are separate components from the trampoline board deck and are very important parts of the total trampoline board  100  interface. The main function of the bindings  600 ,  605  is to hold the user&#39;s feet in place tightly so energy is transmitted between the board and user, without enhanced risk of injury to the user. The bindings  600 ,  605  are attached to the board with a plurality of screws that engage inserts molded into the board  100 , as discussed more fully below. 
     While a wide range of bindings may be used in connection with a trampoline board in accordance with principles of the invention, key features of a preferred binding  600  are conceptually illustrated in  FIG. 6 . Notably, the binding  600  is sized and configured to accommodate a bare foot, a foot in a sock and/or a foot in ordinary street footwear. The binding  600  generally resembles a sandal, an open type of footwear, consisting of a sole held to the wearer&#39;s foot by cushioned straps  665 ,  675  passing over the instep and one or more cushioned straps  645  around the heel and/or ankle. The sole comprises a soft insole  605  that sits directly beneath the wearer&#39;s foot and is sized to be slightly larger than the foot, an outsole  640  that directly contacts the deck of the trampoline board, and, between the insole  605  and outsole  640 , a midsole  680  (preferably a resilient intermediate layer) that provides shock absorption. The rear part of the insole  605  includes a heel pad  635  or cup to accept, stabilize and support the heel of a foot. A cushion  625 ,  660 ,  670  is attached to the insole side of each strap  645 ,  665 ,  675  to comfort a wearer. The heel strap  645  is adjustably (e.g., pivotally) attached to the sole. By way of example, pivot pins  650 , pivotally attach the heel strap  645  to support flanges  620 ,  650 . The straps  645 ,  665 ,  675  may be adjusted using buckles, clamps, ratchets  610 ,  615 ,  630  (e.g., as in the case of ratchet straps which are widely used in snowboard and wakeboard bindings) or other mechanical releasable securing devices. 
     The sole may be used to secure the binding  600  to the deck  205 . By way of example and not limitation, the insole  605  may be removable to reveal screws or other attachment means for securing the binding to a trampoline board  100 . After the binding is secured, the insole may be adhesively or mechanically (e.g., via adhesive or hook and loop fasteners) secured back in place on the sole to protect a foot from the attachments. The outsole  640  provides a secure surface between the attachments and the deck  205  of the board  100 . Alternative mountings such as a plate and thumbscrew base mounting system may be provided as is commonly provided in conventional wakeboard bindings. 
     The exemplary trampoline board bindings differ substantially from wakeboard and snowboard bindings, neither of which is well suited for safe and effective trampoline use. Notably, the binding does not have any features that may gouge, scratch, dig in or otherwise injure a user during trampoline maneuvers. By way of example and not limitation, the binding does not have stiff molded supports behind the heel and up the calf area to allow riders to apply pressure and effect a “heelside” turn on the slopes, as do snowboard bindings. Nor does the binding have a stiff molded foot and ankle support as commonly found in wakeboard bindings. Extended molded features as the stiff molded support in the case of a snowboard binding and the stiff molded foot and ankle support in the case of a wakeboard binding are conducive to injury by digging into the user&#39;s legs, calves and derriere during trampoline maneuvers. 
     Another notable difference between the exemplary trampoline board bindings and conventional wakeboard and snowboard bindings is the resilient midsole  680 . During trampoline maneuvers, shocks are repeatedly transmitted through the sole of the binding  600 . The midsole  680  provides a stable, resilient, shock absorbing layer between the insole  605  and outsole  680 , which is a unique feature that is neither required nor found in wakeboard or snowboard bindings. 
     The invention is not limited to the board shape, configuration or arrangement of components as shown in the Figures. For example, arrangements of furrows and channels other than as shown in  FIGS. 1 through 4  are feasible and intended to come within the scope of the invention. Likewise, the board may be shaped to resemble a wakeboard, snowboard, skateboard or any other sports or recreation board. Illustratively, an alternative trampoline board (i.e., board) is shown in  FIGS. 7 , and  8 , generally indicated at  700 . The deck of the body  710  of the board  700  includes a plurality of furrows  735 ,  770  along the lateral edges  707 ,  709 , as well as furrows  755 ,  795  along the tail and tip, to facilitate gripping. A central (i.e., between tip and tail) divergent (i.e., expanding in width from the midline to lateral edges) channel  730  extends from one lateral furrow  735  to the opposite lateral furrow  770 . The channel  730  facilitates bending (i.e., folding) of the board  700  during use. 
     Referring now to  FIGS. 9 ,  10  and  11 , exemplary inserts are shown. Inserts  900  or  1100  (also known as insert packs) are molded into the body  110  of the board  100  for purposes of securing the bindings  600 . Pluralities of exposed threaded tips  105 ,  160  of the inserts  900  or  1100  are accessible for attachment of bindings at the deck  205 . The inserts  900 ,  1100  comprise a broad sheet-like base  905 ,  1105  with parallel threaded shanks  915 ,  1115 ,  1130  extending perpendicularly therefrom. The broad base  905 ,  1105  enhances retention of the inserts in the body  110  of the board  100 . Threaded apertures  910 ,  1120 ,  1125  are provided to receive screws from bindings. The shanks  915 ,  1115 ,  1130  are configured to receive screws from compatible trampoline board bindings. The shanks may preferably be configured not to accept conventional wakeboard and snowboard bindings, to avoid misuse. Heads  920  at the bottom of the shanks prevent the shanks from being withdrawn from the base  905 ,  1105  when under a tensile force. The shanks  915 ,  1115 ,  1130  may be molded or bonded to the base  905 ,  1105 . The key difference between the insert in  FIGS. 9 and 10  and the insert in  FIG. 11 , is that the insert in  FIGS. 9 and 10  is a separate discrete unit for one binding, while the insert in  FIG. 11  is an integrated unit with an intermediate stiffening joint  1105  to provide enhanced rigidity and retention. 
     One or more elongated flexible stiffeners (also known as stringers) may be molded into the body  110  of the board  100  parallel to the lateral edges to enhance rigidity, reduce deformation, and add stiffness and recoil to the body  110 . The stiffeners may be perforated and/or textured to enhance bonding with and resist delamination from the core  1205  of the body  110 . If a single stringer is used, it may be placed in the center of the board midway between and running parallel to the lateral edges. Stiffeners may be comprised of ABS, PVC, polyethylene, carbon, graphite, bamboo or similar structural materials. 
     Referring to  FIG. 12 , a cross-section of trampoline board  100 , taken along line B-B of  FIG. 4 , is shown. Body  110  of trampoline board  100  includes a core section  1205 , a bottom skin and a top skin  1200 . An insert  900  is molded into the core  1205 , with the free ends of the threaded shanks being accessible at the top skin  1200  which covers the deck  205 . The core  1205  may comprise a thermoplastic or thermoset elastomer, such as ethylene vinyl acetate (EVA), high-rebound polyurethane (HRPU) or other similar materials. The core may be approximately as thick as a conventional wakeboard, e.g., between 0.25 and 1.5 inches. The top and bottom skins  1200  may comprise a solid polymer sheet having good durability, such as high density polyethylene (HDPE), extruded polyurethane or Surlyn® (DuPont) thermoplastic. By way of example and not limitation, in one embodiment, the body  110  may comprise an HRPU core  1205  with a spandex or elastane fabric intermediate layer  1300  (as shown in  FIG. 13 ) and an extruded polyurethane exterior sheet  1305  heat laminated to the spandex intermediate layer  1300 . Suitable spandex or elastane fabrics include Lycra®, a trademark of Invista (formerly part of DuPont), Elaspan® (also Invista&#39;s), Dorlastan® (Asahi Kasei) and Linel® (Fillattice). In another embodiment, an EVA core  1205  may be encased in HDPE skins  1200 . The bottom skin  1200  may be textured and/or have a tackiness. Advantageously, such materials may be bent to conform to a trampoline surface, but may also be sufficiently rigid to avoid fluttering. 
     The body  110  of the board  100  may be decorated with text and graphics. For example, text and graphics may be printed or otherwise displayed on the outer layer. Alternatively, text and graphics may be sublimated on the intermediate spandex layer and visible through a transparent or translucent outer polyurethane layer. Inks or dyes, after being sublimated, diffuse or otherwise transfer into the spandex layer and thereafter remain as a durable decoration. In this way, even after extensive use of the board, the inks beneath the surface are exposed so that the text and graphics endures and remains vibrant. 
     Optionally, an antislip pad  1400  (or coating) may be provided on the bottom surface of the body  110  of the board  100  as shown in  FIG. 14 . The pad  1400  features a high coefficient of friction to enhance traction and prevent a rider from slipping off of trampoline while using the board  100 . An exemplary pad  1400  may be comprised of any pliable sheet-like materials, including cured silicone, Neoprene® (DuPont), or polyurethane gel. 
     One method of manufacturing trampoline boards according to principles of the invention entails placing sublimated spandex skins in a mold and drawing a vacuum to force the skins to conform tightly to the shape of the mold. The mold includes a top half and a bottom half with an interface along the midline of the board between the top and bottom surfaces, ports for drawing a vacuum and, optionally, ports for introducing resin between the skins. After the skins are placed into the mold, inserts for threadedly attaching bindings to the board  100  are placed into the mold. Using support pins as spacers, the base  905 ,  1105  of the inserts  900 ,  1100  are maintained in a position with the threaded engagement shafts extending to the deck. Next, the resin comprising the core is injected, poured, drawn or otherwise introduced into the space between the mold halves and skins. Then the mold halves are urged together under controlled pressure and temperature allowing the resin to cure. When the curing process completes, the molded board with attached skin may be removed from the mold. Any excess skin material may be trimmed and melted to form a clean edge. An extruded transparent polyurethane sheet may then be heat laminated to the spandex layer. A sacrificial layer may be used to protect the core from melting and distortion while the polyurethane sheet is heat laminated to the core. Next, the top polyurethane skin is heeled to the sides and edges of body. Heeling may be done by hand application of pressure and heat using irons, or a similar operation. 
     Referring now to  FIG. 15 , a trampoline  1500  is conceptually illustrated with a trampoline board  100  in accordance with principles of the invention. For clarity, a user is not shown. The trampoline  1500  comprises a piece of taut, strong fabric stretched over a steel frame using many coiled springs to provide a rebounding force which propels the jumper high into the air. The trampoline board  100  conforms to the shape of the deformed fabric surface of the trampoline  1500  during downward deflection. Upon rebound, the trampoline board  100  quickly returns to its undeformed configuration and generally maintains this configuration without appreciable oscillation (i.e., fluttering) throughout aerial maneuvering. 
     In another embodiment as shown in  FIG. 16 , features other than furrows, channels or grooves are provided to facilitate flexing. Such features may include thinned regions  1625 ,  1630 ,  1635 ,  1640 ,  1650 ,  1655 . The thinned regions have a thickness (i.e., thickness measured from top surface to bottom surface) that is less than the thickness of other regions  1645 , particularly those regions to which the binding inserts  1660 ,  1665  are embedded and to which the bindings are attached. These thinned regions  1625 ,  1630 ,  1635 ,  1640 ,  1650 ,  1655  are flex zones. By way of example and not limitation, the midline of the board, between tip and tail, may include thinned regions  1650 ,  1655  near the corresponding lateral edges  1615 ,  1620 . These thinned regions  1650 ,  1655  are intermediate flex zones. In the exemplary embodiment, the surface area comprising intermediate flexed zones  1650 ,  1655  is a maximum at the midline, which is where flexibility is desired to easily conform to the deformed surface of a trampoline under tension. The intermediate flex zones  1650 ,  1655  thus facilitate bending. Other flex zones include corners of the tip  1625 ,  1630  and tail  1635 ,  1640 . These flex zones yield when a user lands awkwardly on a corner, preventing ankle injury and falling from the trampoline. In sharp contrast, rigid boards, which do not include flex zones, frequently cause injury if a user lands on a corner or tip. 
     As discussed above, flex zones are portions of reduced thickness (i.e., thickness measured from top surface to bottom surface) at locations on the board (e.g., the midline between tip and tail) where flexibility is desired to easily conform to the deformed surface of a trampoline under tension. Flex zones act as living hinges, which facilitate controlled bending (i.e., bending during impact with a trampoline surface to conform to the shape of the trampoline surface as it deflects). Concomitantly, the board is resilient, returning to its unbent configuration upon rebound, without fluttering while airborne. 
     While an exemplary embodiment of the invention has been described, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. With respect to the above description then, it is to be realized that the optimum relationships for the components of the invention, including variations in form, function and manner of operation, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. The above description and drawings are illustrative of modifications that can be made without departing from the present invention, the scope of which is to be limited only by the following claims. Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents are intended to fall within the scope of the invention as claimed.