Abstract:
A water sports board with enhanced flexibility includes an elongated core body and an elongated wooden or carbon fiber planar stringer disposed on the centerline of the core body. A plurality of elongated slots are formed in the upper edge of the stringer and extend downwardly toward the bottom edge. The slots are filled with an elastic rubber-like material. The water sports board can be a surfboard, windsurfing board, kite board, wakeboard or body boards.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention is directed toward surfboards and similar boards used for water sports and more particularly, toward such boards that have an improved stringer that allows for improved and selective flexibility of the board. 
         [0002]    Board-shaped riding vehicles have long been a part of water recreation, first as surfboards, and later as sail boards and body boards and the like. Originally, most surfboards were manufactured to be stiff and heavy, with hard exterior surfaces. In more recent years, however, surfboard and sail board manufacturers have utilized synthetic materials to make lightweight boards, and body boards are normally constructed from soft foam materials. 
         [0003]    Most currently available surfboards generally have light density core material glued to a wood stringer positioned at a longitudinal centerline with the entire core and stringer then covered by a hard exterior skin layer. The purpose of the stringer is to provide structural strength to the surfboard. As can be appreciated, the flexibility of the stringer directly affects the flexibility of the surfboard. 
         [0004]    Surfboards are required to flex some amount and at desired locations which may change depending on the surfing conditions and the skill level of the surfer. As pointed out above, almost all commercially available surfboards have one, or sometimes two, thin planar wood stringers that increase the strength of the board that is necessary because of the light density of the core material currently used. 
         [0005]    The flex patterns and characteristics exhibited by existing surfboards are random, not pre-determined and less than optimal. This is mainly due to the random flex characteristics and resistance to flexing of the solid body stringer. Moreover, the material types and the width of the stringers also play a role in the random and uncontrolled flex characteristics. Because of limited flexibility, existing surfboards tend to break easily under harsh wave conditions or repetitive uses. 
         [0006]    Therefore, it is desirable to provide a water sports board having an improved flexibility. It is further desirable to provide a water sports board with selected or predetermined desired flex patterns, which ultimately enhances maneuverability and performance of the board to the rider. Moreover, it is also desirable to provide water sports boards with improved shock dampening property to enhance durability of the boards particularly in extreme environments. 
         [0007]    One suggestion for improving the flexibility characteristics of a surfboard is disclosed in U.S. Published Application No. 2009/0280704 to Fort. Fort proposed cutting holes or windows through the side of the stringer. While this may weaken the stringer allowing it to flex laterally, it does not increase the flexibility of the stringer or of the surfboard in any direction within the plane of the stringer, thereby limiting its effectiveness. Furthermore, when the surfboard core material is glued onto the stringer, the glue can enter the formed openings and solidify, which makes the stringer more rigid, thereby again reducing the flexibility of the stringer and the surfboard. 
         [0008]    A need continues to exist, therefore, for an arrangement that allows a surfboard manufacturer to produce a surfboard with specifically desired flexibility characteristics. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention is designed to overcome the deficiencies of the prior art discussed above. It is an object of the present invention to provide a water sports board with enhanced flexibility. 
         [0010]    It is another object of the present invention to provide a method for constructing a water sports board which allows the maker to readily adjust the flexibility of the same during construction. 
         [0011]    It is a still further object of the present invention to provide such a water sports board that can be produced with a desired flexibility. 
         [0012]    In accordance with the illustrative embodiments demonstrating features and advantages of the present invention, there is provided a water sports board with enhanced flexibility that includes an elongated core body and an elongated wooden or carbon fiber planar stringer disposed on the centerline of the core body. A plurality of elongated slots are formed in the upper edge of the stringer and extend downwardly toward the bottom edge. The slots may be filled with an elastic rubber-like material. The water sports board can be a surfboard, windsurfing board, kite board, wakeboard or body boards. 
         [0013]    Other objects, features, and advantages of the invention will be readily apparent from the following detailed description of the preferred embodiment thereof taken in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    For the purpose of illustrating the invention, there is shown in the accompanying drawings one form which is presently preferred; it being understood that the invention is not intended to be limited to the precise arrangements and instrumentalities shown. 
           [0015]      FIG. 1  is a perspective view of the core of a surfboard; 
           [0016]      FIG. 2  is an exploded perspective view showing the principal component parts of the surfboard core; 
           [0017]      FIG. 3  is a side elevational view of the improved stringer of the present invention; 
           [0018]      FIG. 4  is a perspective view similar to  FIG. 2  but showing the improved stringer being utilized; 
           [0019]      FIG. 5  is a perspective view similar to  FIG. 1  but showing the surfboard core reassembled with the improved stringer therein; 
           [0020]      FIG. 6  is a perspective view similar to  FIG. 2  but showing a modified form of the stringer being assembled, and 
           [0021]      FIG. 7  is a perspective view similar to  FIG. 2  showing the use of the improved modified form of the stringer of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    Referring now to the drawings in detail wherein like reference numerals have been used throughout the various figures to designate like elements, there is shown in  FIGS. 1-7  an improved surfboard core constructed in accordance with the principles of the present invention and designated generally as  10 . The core  10  shown in  FIG. 1  is covered with fiberglass or other similar fabric material which is normally bonded thereto in a manner well known in the art to form a hard exterior skin layer. Accordingly, a detailed description thereof is not believed to be necessary. 
         [0023]    The surfboard core  10  is comprised of several component parts including two substantially symmetrical halves  12  and  14  each of which has a nose end such as shown at  16  and  18  and a tail end shown at  20  and  22 . The core halves  12  and  14  also have top surfaces  24  and  26  and bottom surfaces, only one of which,  28 , is shown in the figures. 
         [0024]    As is well known in the art, the surfboard has a defined curved shape which is shown in the figures. This is, of course, by way of example only as various other shapes are known. The length and width and curvature of the board depends on the use to which it is going to be put and, frequently, the skill of the person utilizing the same. 
         [0025]    The two core body halves  12  and  14  are preferably comprised of lightweight, synthetic plastic materials. Frequently these are relatively dense foam materials. This helps to make the boards lighter and more flexible. 
         [0026]    Located along the center line between the core body halves  12  and  14  is an elongated planar stringer  30 . The stringer has a height which goes from the top edge  32  to the bottom edge  34  thereof and a front end  36  and front rear end  38  and two side surfaces  40  and  42 . 
         [0027]    In the most common manufacturing process, the core body  10  is prepared by assembling a somewhat rectangularly shaped stringer between two substantially rectangularly shaped core halves and then machining the combination into the desired curved shape. One method of practicing the present invention is to then remove the three component parts  12 ,  14  and  30  as shown in  FIG. 2  by ungluing them. It is not beyond the scope of the present invention, however, to start with the three component parts already shaped and then assembling them. 
         [0028]    As shown most clearly in  FIG. 3 , a plurality of slots or notches  44  are formed in the stringer  30 . The notches are preferably formed in the upper edge  32  and extend downwardly toward but not completely through to the lower edge  34 . The number, size and shaping of the slots  44  will depend on the degree of flexibility that is desired and the position on the board where the flexibility is desired. 
         [0029]    In the preferred embodiment, the slots  44  are formed in the top edge of the board and extend substantially vertically downwardly. It is not beyond the scope of the present invention, however, for the slots to extend downwardly at an angle nor is it required that they have straight side walls. Other arrangements are possible. By way of example and not limitation, the slots could be triangularly shaped such as shown at  46 . Furthermore, in some situations, it may be desirable to include a slot that goes upwardly such as shown at  48 . 
         [0030]    After the stringer is provided with the desired slots such as shown in  FIG. 3 , the two halves  12  and  14  of the core are glued to the side faces  40  and  42  of the stringer as shown in  FIGS. 4 and 5 . The core is then covered with a hard exterior skin layer as discussed above. During this assembly, gluing and covering process, rigid adhesive material can flow into the slots. To prevent this and to provide further control over the flexibility of the stringer, some or all of the slots can be filled with a rubbery or elastic material such as shown at  50  in  FIG. 3 . 
         [0031]    The stringer of the present invention and those that are conventional in the art are frequently made of wood. It is possible, however, to make the stringer of other materials such as carbon fiber. Furthermore, and as shown in  FIGS. 6 and 7 , the stringer can be a laminate having a center  52  of wood between two carbon fiber layers  54  and  56  as shown in  FIGS. 6 and 7 . In this embodiment, the laminate is preferably combined before the slots are formed therein. 
         [0032]    Although reference has been made herein to a surfboard, it should be readily apparent that substantially any water sports board can be made in accordance with the present invention. This would include surfboards, wind surfing boards, kite boards, wakeboards and body boards. 
         [0033]    The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and accordingly, reference should be made to the appended claims rather than to the foregoing specification as indicating the scope of the invention.