Patent Publication Number: US-8979604-B1

Title: Flying ski and elongated board for flying ski

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 61/506,882, filed Jul. 12, 2011, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This application relates to recreational water equipment and, in particular, to flying skis and methods of making flying skis. 
     2. Description of the Related Art 
     U.S. Pat. Nos. 5,100,354, 5,249,998, and 7,097,523 disclose an apparatus known as a flying ski. The flying ski is a device adapted to be towed behind a powered watercraft in a manner similar to a water ski. In contrast to a water ski, however, the rider sits on a seat spaced above the ski board and primarily rides on a blade structure that is spaced below the ski board by a vertical strut. When the ski is in use, the rider, seat and board are above the water surface and the blade structure is submerged below the water surface. The flying ski disclosed in the above-identified patents was a pioneering recreational water device. 
     SUMMARY OF THE INVENTION 
     Disclosed herein are embodiments of flying skis and elongated boards for flying skis. Certain embodiments include an elongated board configured for use with a recreational device that supports a seated human rider while the rider and the device are towed behind a powered watercraft. The elongated board can include a front end and a back end. The front end extends from a front edge to about one-half of the length of the elongated board and the back end extends from a back edge to about one-half of the length of the elongated board. The back end includes an opening configured to couple with a seat portion extending upward from a top side of the back end of the board and a strut extending downward from a bottom side of the back end of the board. The back end has a greater mass than the front end. Furthermore, a back one-third of the board may have a greater mass than a front two-thirds of the board. For example, the back one-third of the board may have a back mass per square inch surface area and the front two-thirds of the board may have a front mass per square inch surface area less than the back mass per square inch surface area. 
     In certain embodiments, an elongated board includes a foam core, a first fibrous layer on a top surface of the foam core, and a second fibrous layer on a bottom surface of the foam core. At least one hole can extend through the foam core and the fibrous layer. An inner surface of the at least one hole includes fibers and a resin such that the resin extends from the first fibrous layer to the second fibrous layer. The resin, the first fibrous layer, and the second fibrous layer may form a unitized structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a flying ski in accordance with certain embodiments described herein, illustrating the general orientation of the ski when in use and supporting a seated human rider being towed behind a powered watercraft (not shown); 
         FIG. 2  is an exploded perspective view of the ski of  FIG. 1 , illustrating component parts of the ski; 
         FIG. 3  is an exploded perspective view of a board in accordance with certain embodiments described herein, illustrating layers that can be included in the board; 
         FIG. 4  is an exploded perspective view of a board illustrating layers that may be included in certain boards; 
         FIG. 5A  is a top view of a board with preliminary strut hole and bolt holes in accordance with certain embodiments described herein; 
         FIG. 5B  is a magnified portion of the preliminary strut hole and bolt holes of the board of  FIG. 5A  with the preliminary holes at least partially filled with a resin; 
         FIG. 5C  is the magnified portion of the board of  FIG. 5B  with a fibrous layer applied to the top of the board (the dashed lines illustrating the preliminary holes underneath the fibrous layer); 
         FIG. 5D  is the magnified portion of the board of  FIG. 5C  with final holes formed through the fibrous layer and the resin in the preliminary holes to form final holes reinforced by the resin; 
         FIG. 5E  is a first cross-sectional view of the board of  FIG. 5D . 
         FIG. 5F  is a second cross-sectional view of the board of  FIG. 5D . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Disclosed herein are embodiments of flying skis and elongated boards for flying skis. Certain embodiments of skis and boards may be disclosed in the context of the types of skis disclosed in U.S. Pat. Nos. 5,100,354, 5,249,998, and 7,097,523, each of which are incorporated by reference in their entirety herein. The principles of skis and boards described herein, however, are not limited to the types of flying ski in those disclosures. Instead, it will be understood by one of skill in the art, in light of the present disclosure, that the improved types of skis and boards disclosed herein can also be successfully utilized in connection with other types of skis, both presently known and later developed, as well as other recreational water and nonwater devices. One skilled in the art may also find additional applications for the improvements disclosed herein. However, the skis and boards described herein are particularly advantageous in connection with the types of flying ski disclosed in the incorporated patents. 
     With reference to  FIGS. 1 and 2 , the flying ski  10  includes an elongate board  20  having an upper face  22  and a lower face  24 , and a front end  26  and a rear end  28 . A seat  30  extends generally perpendicular to and upward from the upper face  22  of the board  20  to support the seated rider&#39;s buttocks. The rider&#39;s legs extend toward the front end  26  of the board  20  and are secured by a pair of foot holders  32 ,  34  that attach to the board  20 . An elongate strut  36  extends generally perpendicular to and downward from the board  20  and couples the seat  30  to a planing blade  38 . The planing blade  38  advantageously has a front blade  40  and a rear blade  42  interconnected by a fuselage  44 . 
     With reference to  FIG. 1 , the improved flying ski  10  is desirably towed behind a conventional powered watercraft (not shown) utilizing a standard ski tow rope or similar device having a handle that can be held by the human rider (illustrated at a point spaced above the rider&#39;s knees for rider comfort). In use, the rider is seated on the seat of the flying ski and towed by the watercraft. 
     Referring to  FIG. 2 , the elongate board  20  is configured generally similar to the boards of the incorporated patents. The board  20  has a longitudinal length of about 0.5 to 5 m, more preferably about 1 to 2 m and most preferably about 1.3 m. The front portion of the board is curved upward at an increasing rate toward the front end  26  of the board  20 . That is, the rear end  28  of the board  20  is substantially planar in the longitudinal direction while the front end  26  has approximately one foot of rise. The lateral width of the board  20  is generally bullet shaped, with the rear end  28  width about 200 mm, a midsection width of about 300 mm, and a front end  26  nose width of about 20-40 mm. 
     The board  20  is preferably manufactured by compression molding. However, in other embodiments the board  20  can be manufactured through a variety of other suitable manufacturing techniques, both presently known or later developed. 
     The board  20  can include holes to couple the seat  30  and the strut  36  to the board  20 . For example, the board  20  can include a strut hole  11  to accommodate the strut  36  and a plurality of bolt holes  13  (e.g., D-nut holes) to accommodate bolts to mount the seat  30  to the board  20 . The strut hole  11  may be, for example, about ⅝ inches wide and about 4 inches long. The board  20  may include four holes with two on each side of the strut hole  11  and two in front and in back of the strut hole  11 . The holes are generally in a rear end  28  of the board  20 . The board  20  may break during use, and a common location for failure to begin in a board  20  is at the holes and in particular the strut hole  11 . A crack often starts at the strut hole  11 , heads over to a front bolt hole  13 , and out an outer edge of the board  20 . 
       FIG. 3  is an exploded perspective view of a board  300  in accordance with certain embodiments described herein. The board  300  includes a foam core  302  sandwiched between a plurality of top layers  304  and a plurality of bottom layers  306 . The type of layers in the top layers  304  and bottom layers  306  can be similar or may be different in at least one aspect such as number of layers. 
     The top layers  304  and bottom layers  306  can include one or more fibrous layers  308  (e.g., fibrous patches) that include one or more types of fibers. For example, the fibrous layers  308  can include carbon fibers or glass fibers. The fibers may be substantially unidirectional or uniaxial within each layer. Fibrous layers  308  that are adjacent to one another can have unidirectional fibers that have orientations that are different relative to one another. For example, the fibrous layers  308  can have a fiber direction that is parallel with the board  300 , across the board  300 , or at other directions relative to the board  300 . Mechanical properties can be improved by having the orientation or angle of the fibers in each neighboring fibrous layer  308  be varied. For example, resistance to crack propagation can be reduced. The fibrous layers  308  may also include layers that have crosshatched or bidirectional fibers.  FIG. 3  illustrates example orientations of the fibrous layers  308  with direction of hatchings. 
     To improve failure resistance, the number of fibrous layers  308  can be increased. However, the weight of the board  300  increases as the number of fibrous layers  308  is increased, and as a result, the performance of the flying ski can be reduced. Since the source of failure generally originates at the rear end  310  of the board  300  where the strut hole  314  and bolt holes  316  are located, the rear end  310  can include more fibrous layers  308  than the front end  312  of the board  300 . For example, the rear end  310  may include about 24 fibrous layers  308  while the front end  312  may include about six fibrous layers  308 . In certain embodiments, the ratio of the fibrous layers  308  in the rear end  310  to the fibrous layer  308  in the front end  312  can be about 4:1 to about 100:1. Furthermore, the ratio of the fibrous layers  308  in the rear one-third of the board  300  to the fibrous layers  308  in the front two-thirds of the board  300  may be about 4:1 to about 100:1. The number of fibrous layers  308  in the top layers  304  may also be different than the number of fibrous layers  308  in the bottom layers  306 . 
     Each of the fibrous layers  308  can extend from approximately the back edge  318  of the board  300  to a position between the front edge  320  of the board  300  and the back edge of the board  300 . Each of the fibrous layers  308  may extend at least beyond the holes  314 ,  316  to improve structural strength around the holes  314 ,  316 . The mechanical properties of the board  300  can be further improved by having the fibrous layers  308  extend to different positions between the front edge  318  of the board  300  and the holes  314 ,  316 . For example, the fibrous layers  308  can have an adjacent or neighboring fibrous layer  308  that is longer and another adjacent or neighboring fibrous layer  308  that is shorter (e.g., a first fibrous layer  308  may be sandwiched between a second fibrous layer  308  that is longer a third fibrous layer  308  that is shorter than the first fibrous layer  308 ). In other words, the fibrous layers  308  can each be longer than the one before it as fibrous layers  308  progress out from the foam core  302 . For example, each fibrous layer  308  can be about 1 to about 1.5 inches longer than the one before it. The fibrous layer  308  furthest from the foam core  302  can extend the entire length of the board  300  from the back edge  318  to the front edge  320  of the board  300  to provide some strength to the front end  312 . Furthermore, the front end  312  may only include a single fibrous layer  308 . The fibrous layer  308  that extends the entire length of the board  300  may have a fiber direction parallel with the length of the board  300 . In addition, each of the fibrous layers  308  can have a front edge  322  with a v-shape or a curvature. A board  300  with fibrous layers  308  with v-shape front edges  322  can have further improved failure resistance compared front edges  322  that are straight across the board  300 . 
     The board  300  can result in significantly less weight compared to certain typical boards. Certain typical boards can weight around about 10 to about 14 lbs and have a balance point (e.g., center of mass) in the center of the board, so the front of the board weighs as much as the back of the ski. By minimizing the fibrous layers  308  in the front end  312  of the board  300 , the weight can be reduced to about 6 lbs, and the board  300  can have a center of mass closer to the back end  301  than the front end  312 . The performance of the flying ski is increased even further than merely due to the weight reduction. The flying ski rotates by the planing blade  38 , shown in  FIGS. 1 and 2 . Since the board  20  extends out from the strut  36 , the front end  26  of the board  20  acts as cantilever weight. Therefore, by reducing the weight at the front end  312  of the board  300 , the flying ski can be significantly easier for the rider to maneuver. 
     The board  300  can be about 54 inches long and all but about 12 inches of the board  300  extends out in front of the seat. However, the back about 12 inches of the board  300  tends to be where the board  300  brakes or fails. Therefore, about 42 inches or about two-thirds of the board  300  extends out front that acts as cantilevered weight. By minimizing the weight on the front ⅔ of the board  300  by minimizing the number of fibrous layers  308  on the front end  312 , the front ⅔ may weight about ⅓ of the total weight of the board  300  and the back ⅓ may weight about ⅔ of the total weight of the board  300 . For example, the back ⅓ may weight about 4 pounds while the front ⅔ may weight about 2 pounds. 
     As described above, the board  300  may have a generally bullet shape such that the front end  312  may be wider than the back end  301  of the board  300 . When the front end  312  is wider than the back end  301 , the front end  312  may weigh even more than the back end  301  if all of the fibrous layers  308  extend the entire length of the board  300 . In particular, the front end  312  may have a front surface area and the back end  301  has a back surface area less than the front surface area. For example, the front ⅔ of the board  300  may be about 12 inches wide (except for the front tip) while the back ⅓ of the board  300  may be about 6 to about 8 inches wide. The result can be the front ⅔ of the board  300  has a surface area of at least about three times a surface area of the back ⅓ of the board  300 . However, by minimizing the number of fibrous layers  308  that extend to the front end  312  of the board  300  as described herein, the weight of the front end  312  can be less than the back end  310  even when the front end  312  is wider (e.g., has a greater surface area) than the back end  310 . 
     Furthermore, the front end  312  can have a front mass per square inch surface area and the back end  301  can have a back mass per square inch surface area less than the front mass per square inch surface area. For example, the front mass per square inch surface area may be at least three times less than the back mass per square inch surface area. Furthermore, the mass per square inch surface area of the front ⅔ of the board  300  may be at least three times less than the mass per square inch surface area of the back ⅓ of the board  300 . 
     The fibrous layers  308  can be sandwiched between additional layers and the foam core  302 . The additional layers can include a barrier paper  324  adjacent the fibrous layers  308 . The barrier paper  324  can block sun rays from the carbon fiber to prevent degradation of the carbon fiber. A nexus layer  326  can be sandwiched between the barrier paper  324  and graphics  328 . The nexus layer  326  can act as an impact absorber and can also improve adhesion of the graphics  328  compared to the barrier paper  324 . The barrier paper  324  also helps eliminate texture on the surface of the board  300  as a result of the texture of the fibrous layers  308  as well as covers the black color of the carbon fiber. The barrier paper  324  can be white which can improve the appearance of the graphics  328 . 
     Certain boards typically have a plurality of fiber glass layers with each extending the entire length of the board.  FIG. 4  is an exploded perspective view of an example board  200  illustrating layers that may be included to show some of the differences from the board  300  illustrated in  FIG. 3 . In particular, the board  200  in  FIG. 4  includes a plurality of fiber glass layers  408  with each fiber glass layer extending the entire length of the board  400 . As discussed above, by having the fiber glass layers extend all the way from the back to the front of the board  400 , the front of the board  400  may weigh as much as or more than the back of the board which can negatively impact the performance of the ski. 
     Certain typical methods of making broads includes fiberglass wrapped around a foam core. The strut holes and bolt holes are drilled or routed out after the fiberglass has been applied to the foam core. The foam core is then exposed on the inside of the holes. As discussed above, the holes are often the location of failure of the board. Described below is an improved hole structure that can improve failure resistance around the holes. 
       FIG. 5A  illustrate a top view of an example board  500  and  FIGS. 5B-5F  illustrate partial top views of the board  500  at various stages of formation of an improved hole structure. Referring to  FIG. 5A , preliminary holes  502  can be formed in the foam core  506  that extend from a top surface to a bottom surface of the foam core  506  prior to the layers being applied thereto. For example, about ¾ inch diameter holes can be made for the four bolt holes and an about 4 by about ⅝ inch hole can be made for the strut hole. As compared to the strut hole sizes described above, the preliminary hole  502  is made to have about an extra ¼ inch all around the hole. Therefore, the preliminary hole  502  is about ½ inch wider and about ½ inch longer. In certain embodiments, a preliminary hole  502  is made to be about ⅛ inch to about ½ inch extra all around the hole compared to the desired final hole size. Alternatively, the preliminary hole  502  can be made to be about ¼ to about ¾ inch wider and longer compared to the desired final hole size. 
     Referring to  FIG. 5B , the preliminary holes  502  that were formed in the foam core can be at least partially filled with fibers and a resin  504 . The resin can include a slow reacting catalyst so that there is additional time to apply the fibrous layers before the resin cures. The fibers can be, for example, carbon fibers. A second resin is than applied to the foam core  506  and the fibrous layers  508  are applied, as illustrated in  FIG. 5C .  FIG. 5C  has the preliminary holes illustrated with dashed lines to illustrate that the fibrous layer  508  is applied on top of the holes  502  and the foam core  506 . The second resin can include a faster catalyst than the resin used to fill the holes  502  in the foam core  506 . After applying the fibrous layers  508 , the barrier paper is applied to the fibrous layers, the nexus layer applied is to the barrier paper, and the graphics are applied nexus layer. Layers can be applied to a first side (e.g., top side), the board can be turned over, and layers can be applied to a second side (e.g., bottom side) of the board. The layers on the bottom side of the board can wrap up the side of the board which provides additional strength of the board. The assembled layers are then placed into a mold for compression molding. After compression molding is complete, the board is removed from the mold and flashing can be trimmed. 
     Referring to  FIGS. 5D-5F , the final holes  510  for the strut hole and bolt holes can then be routed out using, for example, a CNC router. The final holes  510  are formed through the fibers and solid resin  512  in the holes  502  such that at least some the fibers and solid resin  512  remains that is adjacent the foam core  506 . For example, the strut hole can have an about ¼ inch thick solid resin layer all the way around the inside of the hole. An about 5/16 inch hole can, for example, be drill through the resin in the bolt holes to similarly have a solid resin layer all the way around the inside of the holes. The resin in the holes  502  can bonded or set up together with the resin applied to the rest of the foam core  506  to form a unitized structure (e.g., single piece structure or continuous structure). The solid resin  512  provides strength to the final holes  510  and can at like trusses. With boards that have an exposed foam core in the bolt holes, when the bolts are tightened, the bolts may crush the foam core if over tightened. The solid resin  512  can help prevent the foam core  506  from crushing as a result of over tightening the bolts. 
     Although boards for flying skis have been described in terms of certain preferred embodiments and suggested possible modifications thereto, other embodiments and modifications apparent to those of ordinary skill in the art are also within the scope of the boards described. It is also understood that various aspects of one or several embodiments or components can be used in connection with another or several embodiments or components. Accordingly, the scope of the boards and skis is intended to be defined only by the claims that follow.