Patent Publication Number: US-11046396-B2

Title: Adjustable surfboard fin and method of use

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application No. 62/871,171, filed Jul. 7, 2019 which is incorporated by reference herein in its entirety. 
    
    
     COPYRIGHT STATEMENT 
     A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 
     FIELD 
     The present disclosure relates, in general, to surface water sports, and more particularly to stand up surfing and the performance of the associated surfboards. 
     BACKGROUND 
     Surfboarding is beyond a watersport. For many living in coastal areas, it is a way of life. However, each person&#39;s experience with their surfboard is unique. The boards vary greatly in design and length to accommodate the various different riding styles and preferences. For many, a tube ride in the big waves is the goal, while for others carving or performing tricks such as aerials (with rotation or straight), cutbacks, top turns, flips and grabs on the board is the ultimate. Simply stated, there is a plethora of different riding styles and objectives on a surfboard. 
     The one thing in common for all surfboard maneuvers, is that the board direction must be allowed to be dictated by the surfer. Since the surfboard is basically a hydro-dynamic plank, without a perpendicular fin that resides deeper in the water, there is little below the surface to allow the surfer to grab the water and steer their course of direction. The surfboard&#39;s fin (or fins) are designed to continuously track the nose of the surfboard in a leading position in relation to the surfboard&#39;s tail while moving. When in a forward trajectory, the surfer transfers their body weight on the top of the surfboard to navigate (steer) the surfboard. This body weight transfer changes the board&#39;s (hull) position which in turn also changes the fin&#39;s orientation in the water. 
     Notably, besides acting as a rudder to steer, the fin also serves to prevent sideways motion of the surfboard. The deeper the surfboard&#39;s fin is in the water the greater the directional stability of the surfboard with respect to its linear axis while in a forward trajectory. However, such directional stability is not desirable for all styles of riding. Trick or stunt surfers often want a minimum of depth or absence of the fin in the water so that the board can quickly be rotated on the surface of the water. 
     While surfboard design has evolved as its technology has improved, surfboard fins have seen minimal improvements. Basically, they remain rigid planar members, mechanically affixed and solidly locked onto the bottom side of the surfboard&#39;s tail section. Thus, the surfboard fin cannot be altered, moved, or disengaged in relation to the surfboard body by the user. 
     Henceforth, an improved fin design that allows the different surfers to control and steer the surfboard to suit their particular style of surfing that day, would fulfill a long felt need in the surfing industry. This new invention utilizes and combines known and new technologies in a unique and novel configuration to overcome the aforementioned problems and accomplish this. 
     BRIEF SUMMARY 
     In accordance with various embodiments, a surfboard with a replaceable, interchangeable fin that can adjust its depth while in use, so as to provide a new and improved style of surfing, is provided. 
     In one aspect, a surfboard with a depth adjustable fin that can be adjusted by manipulation of the leash around the ankle of the surfer, while the surfboard is in motion, is provided. 
     In another aspect, a surfboard fin that is torsionally or otherwise predisposed for complete insertion under the surfboard, yet may be removed partially or entirely by application of an upward tensional or compressive force from below, is provided. 
     In yet another aspect, a method of riding a surfboard wherein the depth the fin resides in the water is adjusted by the rider while the surfboard is in use. 
     In yet another aspect, a surfboard fin assembly for integration into a surfboard body, that incorporates a downward biased, forward pivotable fin in a housing having an open back end to accommodate the pivotal movement of the fin from the housing. 
     In a final aspect, a surfboard fin assembly with a pivotable fin able to rise or lift upward from its fully inserted position in its housing upon contact from an object below the bottom of the surfboard, to protect the fin from damage. 
     Various modifications and additions can be made to the embodiments discussed without departing from the scope of the invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combination of features and embodiments that do not include all of the above described features. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A further understanding of the nature and advantages of particular embodiments may be realized by reference to the remaining portions of the specification and the drawings, in which like reference numerals are used to refer to similar components. 
         FIG. 1  is a perspective view of a surfer on a surfboard applying a force to the means for tensioning so as to raise and pivot the fin from the top, front edge of the fin box; 
         FIG. 2  is a bottom view of a surfboard with an adjustable fin assembly; 
         FIG. 3  is a top, side perspective view of the fin assembly with the fin in a down (biased) position; 
         FIG. 4  is a top, side perspective view of an alternate embodiment fin assembly with the fin in a down (biased) position; 
         FIG. 5  is a bottom, side perspective view of the fin assembly with the fin in a down (biased) position; 
         FIG. 6  is a top, perspective view of the pivot plate and fin; 
         FIG. 7  is a bottom, perspective view of the pivot plate and fin; 
         FIG. 8  is a bottom, perspective view of the alternate pivot plate and fin; 
         FIG. 9  is a cross sectional view of the alternate pivot plate and fin taken through the vertical centerline of the fin; 
         FIG. 10  is a bottom, perspective view of a surfboard with an adjustable fin assembly; 
         FIG. 11  is a perspective view of a surfer riding a surfboard while raising the fin; and 
         FIG. 12  is a perspective view of a surfer riding a surfboard with the fin down. 
     
    
    
     DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS 
     While various aspects and features of certain embodiments have been summarized above, the following detailed description illustrates a few exemplary embodiments in further detail to enable one skilled in the art to practice such embodiments. The described examples are provided for illustrative purposes and are not intended to limit the scope of the invention. 
     Reference will now be made in detail to embodiments of the inventive concept, examples of which are illustrated in the accompanying drawings. The accompanying drawings are not necessarily drawn to scale. In the following detailed description, numerous specific details are set forth to enable a thorough understanding of the inventive concept. It should be understood, however, that persons having ordinary skill in the art may practice the inventive concept without these specific details. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first attachment could be termed a second attachment, and, similarly, a second attachment could be termed a first attachment, without departing from the scope of the inventive concept. 
     It will be understood that when an element or layer is referred to as being “on,” “coupled to,” or “connected to” another element or layer, it can be directly on, directly coupled to or directly connected to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly coupled to,” or “directly connected to” another element or layer, there are no intervening elements or layers present. Like numbers refer to like elements throughout. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     The terminology used in the description of the inventive concept herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the inventive concept. As used in the description of the inventive concept and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the described embodiments. It will be apparent to one skilled in the art, however, that other embodiments of the present invention may be practiced without some of these specific details. It should be appreciated that the features described with respect to one embodiment may be incorporated with other embodiments as well. By the same token, however, no single feature or features of any described embodiment should be considered essential to every embodiment of the invention, as other embodiments of the invention may omit such features. 
     Unless otherwise indicated, all numbers herein used to express quantities, dimensions, and so forth, should be understood as being modified in all instances by the term “about.” In this application, the use of the singular includes the plural unless specifically stated otherwise, and use of the terms “and” and “or” means “and/or” unless otherwise indicated. Moreover, the use of the term “including,” as well as other forms, such as “includes” and “included,” should be considered non-exclusive. Also, terms such as “element” or “component” encompass both elements and components comprising one unit and elements and components that comprise more than one unit, unless specifically stated otherwise. 
     As used herein, the term “fin” refers to a generally planar member that is disposed at the back end of a surface watersport board so that its plane resides perpendicular or relatively perpendicular (within 45 degrees) to the X-Y plane in a three-dimensional Cartesian coordinate system. 
     As used herein, the term “biased or predisposed” with respect to the fin, refers to a downward force (torsional or linear) exerted on the fin by the biasing means, that coerces the front pivoting fin into a fully down position within the fin housing of the fin assembly where the fin will remain without the influence of any other external forces. Such forces to pivot the fin in an upward arc could be an upward tension force (angular or straight) from the pull of a leash connected to the top edge of the fin, or alternatively, from an upward compressive force exerted on the bottom edge of the fin in the case when the fin strikes a rock or the sand. 
     As used herein, the term “biasing means” refers to any of a group of springs, torsional or linear (compressive or tensional) connected between the fin and the surfboard body, or the fin and the fin housing, so as to urge the fin into its fully downward position within the fin housing. 
     As used herein, the term “means for tensioning” refers to a flexible connector (herein a leash, or lead or a rope) affixed to at least the fin that may be tensioned to cause the fin to pivot from its fin housing upon the application of a tension force that exceeds the force the biasing means imposes on the fin. 
     The present invention relates to a novel design for a surfboard fin assembly for incorporation into a surfboard body, where the fin assembly has a front pivotable, downward biased, vertically adjustable fin, located in a fin housing and coupled to the surfboard leash; and a method for riding a surfboard that entails raising and lowering the fin while the surfing. Adjusting the depth, the fin extends below the surfboard into the water sets the performance of the surfboard to the desired level of directional control. Having the fin only biased in its down position rather than permanently affixed, allows the fin to move upward when struck thereby avoiding damage. 
     Looking at  FIGS. 1 and 10 , a surfboard  2  with an adjustable, replaceable, hinged surfboard fin assembly  4  ( FIGS. 3 and 4 ) installed, can best be seen. The surfboard hull  6  is a buoyant body consisting of a generally planar top  8 , a generally planar bottom  10  ( FIG. 10 ), a circumferential side  11  disposed between the bottom  10  and the top  8 , a nose  12 , and tail  14 . A means for tensioning  16  (illustrated here as a leash), has connected at its distal end, a releasable leash plug  18  which is frictionally fastened into a plug orifice  19  in the top of the hinge body  20 . The hinge body  20  is pivotally attached to the fin box  22 . The hinge body  20  has the fin  24  affixed perpendicularly from the hinge body&#39;s bottom face  26 . The proximal end of the hinge body  28  is pivotally connected to the fin box  22  by a biasing means  30  ( FIGS. 3 and 4 ) and releasably connected at its distal end  34  by the means for tensioning  16  to the surfer&#39;s ankle. Directional arrow  60  shows the direction of pivotal movement that a surfer can introduce to the hinge body  20  and fin  24  while surfing. 
     The hinge body  20  shown in  FIGS. 6, 7 and 8  is a planar body having a fin  24  affixed along its longitudinal centerline. Preferably it is an enclosed body with a generally planar top face and generally planar bottom face (within the realms of the matching curvature of the surfboard it is incorporated into) so to minimize any drag or friction that it could encounter from water rushing by. It is pivotally attached to the surfboard assembly either at the surfboard itself or at the fin box  22 . The fin  24  extends from the bottom face of the hinge body  20  and may be affixed to the hinge body in various ways. It may be permanently affixed by adhesive means, welding, fiber glass, or with mechanical fasteners such as rivets, screws or the mechanical equivalent, such as is well known in the industry. In one embodiment it is removably mounted into a T-slot in the hinge body  20 . 
     The hinge body  20  shown in the alternate embodiment of  FIGS. 8 and 9 , has a removeable fin  24  that slides into a longitudinal T-slot  50  along the centerline of the hinge body  20 . In this design, the fin  24  has a flange  52  at its top end, residing perpendicular to the fin blade  54  that slidingly engages the T-slot  50 . With the fin  24  slid entirely to the extent of the T-slot a locking T-nut  56  is also slid down the T-slot  50  until it abuts the fin  24  and then its bolt  58  tightened until it frictionally engages the inner face of the T-slot. This type of arrangement to lock a fin in a perpendicular position is commonly used on paddle boards. 
     One of the novel features of this design is that the fin  25  is replaceable with different shape and dimensioned fins, depending of the surfer&#39;s preference. If the fin  24  is permanently affixed to the hinge body  20 , the entire hinge body/fin assembly will have to be interchanged by separating the first leaf  40  and second leaf  42  of the biasing means  30 . If the hinge body  20  has a T-slot to slidingly accommodate a fin  24 , (as discussed further herein) the fin can be interchanged on the fly, outside of a surf shop. 
     Looking at  FIGS. 3 and 5  it can be appreciated that the fin box  22  is configured as an open-ended trapezoid with its open (distal) end at the tail  14  of the surfboard  2 . It is a linear framework with only three walls (sides), no top, no bottom and no distal end wall (side.) It serves to provide a space for the hinge body  20  with its fin  24  to reside and be able to pivot forward and upward, free of any lateral friction from the surfboard assembly. For this reason, its front end and sides closely approximate the configuration of the hinge body  20 . 
     The fin box  22  has three side walls and an open distal end. The three side walls are the same dimensional vertical height as the section of the surfboard  2  that they are incorporated into. These side walls function as a surface for the attachment and incorporation of the fin box  22  into the volume of the surfboard  2 . Depending on the construction of the surfboard, the fin box  22  may be fiber glassed, glued or otherwise mechanically affixed to reside within, yet flush with, the contours of the surfboard  2 . The distal end of the fin box  22  has no side and is open ended so as to allow clearance for the fin  24  as is pivots vertically upward with the hinge body  20 . The distal end could be closed and the fin box  22  moved toward the front of the surfboard  2 , but it is imperative for the fin  24  to sit as far as back in the surfboard  2  as practical to enhance the steering effect on the nose  12  of the surfboard. The fin box  22  is made of a lightweight but strong material, likely a carbon fiber, strengthened polymer, or aluminum as it must withstand the torsional forces exerted by the first leaf  40  of the biasing means  30  without failure. (These torsional forces are transmitted from the lateral forces the water exerts on the fin  24  in the fin&#39;s normal function as a fixed rudder.) It would appear that there need not be a fin box  22  with its long tailing non-parallel sides, but rather just an opening in the surfboard with a front plate to affixed the first leaf  40  of the biasing means  30  to. This is incorrect. The long sides of the fin box  22  strengthen its front face  46  from twisting under the lateral loads on the fin  24 , gaining their strength from the selection of material and their large connected surface areas to the surfboard. 
     Although depicted as trapezoidal, it is known that the fin box  22  and its hinge body  20  may be made in other geometrical operable equivalents such as an ellipse, rectangle, triangle and the like, although they will all require that their distal end be open. 
     The biasing means  30  in the preferred embodiment will be a torsional (wound) spring hinge  38  operably disposed between a first leaf  40  and a second leaf  42  as is well known in the art. The first leaf  40  is affixed to the surfboard  2  as shown in  FIG. 2  and the second leaf  42  is affixed to the top face of the hinge body  44  (or optionally, to the front face of the hinge body  46 ). In the illustrated embodiment, both leaves  40  and  42  will have to be recessed into the surfboard and the hinge body  20  so as to reside flush with the overall contour of the surfboard assembly. With the biasing means affixed between the hinge body  20  and the fin box  22 , the pivot point from which the hinge body  20  and resultant fin  24  rise vertically upward from the water, resides just forward of the front wall  48  of the hinge body  20 , at the midpoint of the torsional spring in the biasing means  30 . The direction of pivotal movement of the hinge body  20  is indicated by directional arrow  60 . ( FIG. 3 ) 
       FIG. 4  shows an alternate assembly wherein the torsional spring hinge  38  of the biasing means  30  has it first leaf  40  affixed to the rear side of the front side wall  48  of the fin box  22 , ( FIG. 5 ) and has its second leaf  42  affixed to the front face of the hinge body  46 . While the preferred embodiment biasing means  30  uses a torsional spring hinge  38 , there are a number of mechanical equivalents that could also accomplish the biased pivotal motion of the hinge body  20  within the fin box  22  such as wound linear springs, elastic cords and the like. In the way of an example, a pair of elastic cords affixed between the back end of the hinge body  20  and the back end of the fin box  22  would also bias the hinge body  20  in a downward position. 
       FIGS. 1, 11 and 12  best illustrate the operations of the adjustable surfboard fin assembly. A surfer  100  frictionally, releasably attaches the distal end of the means for tensioning  16  into the plug orifice  19  and attaches the proximal end of the means for tensioning  16  around his ankle. The surfer  100  mounts the surfboard  2  and enters the water with the fin  24  maintained in its predisposed, downward biased position by the tensional spring forces of the biasing means  30 . The surfer  100  paddles or rides the surfboard  2  to a desired position in the water ( FIG. 12 ) and when the surfboard gains forward momentum and begins upon a trajectory, they rise vertically to stand on the surfboard  2 . Positioned on top of a surfboard  2  the surfer  100  pulls on the means for tensioning  16  until the hinge body  20  pivots at its proximal end  26  about the pivot point of the biasing means  30 . The surfer  100  adjustably trims (raises or lowers the fin by changing the tension on the means for tensioning  16 ) the fin  24  as needed to adjust the level of side slip they want the surfboard to have on the water so they can perform their maneuvers. ( FIG. 11 ) Once finished, the surfer  100  releases the tension on the means for tensioning  16  to lower the fin  24  into the water so that they can have directional control to steer the surfboard back to shore or to another location in the water. 
     While described in terms of an adjustable surfboard fin, it is known that it is a surfboard fin assembly intended for incorporation into a surfboard at the time of fabrication although it may also be manufactured and sold as a kit for retrofitting into an existing surfbord. 
     Having described and illustrated the principles of the inventive concept with reference to illustrated embodiments, it will be recognized that the illustrated embodiments can be modified in arrangement and detail without departing from such principles, and can be combined in any desired manner. 
     Consequently, in view of the wide variety of permutations to the embodiments described herein, this detailed description and accompanying material is intended to be illustrative only, and should not be taken as limiting the scope of the inventive concept. What is claimed as the invention, therefore, is all such modifications as may come within the scope and spirit of the following claims and equivalents thereto.