Abstract:
An apparatus and method of use is disclosed for a water-sport paddleboard incorporating user foot driven reciprocating mechanical features to produce propulsion over the surface of a body of water. Means is provided to enable forward and reverse propulsion and steering while in standing or sitting positions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority of Provisional application No. 61/818,424 filed May 1, 2013. 
     
    
     BACKGROUND 
       [0002]    1. Field of Invention 
         [0003]    This invention relates to an apparatus and methods of use for a reciprocating foot actuated propulsion drive and steering rudder system for water sport paddle-type boards. 
         [0004]    2. Definition of Prior Art 
         [0005]    The history of constructing personal watercraft out of planks or wood (or “boards”) dates back to at least their earliest recorded use by the Hawaiian natives first described in 1769 by Joseph Banks on the HMS Endeavour during the first voyage of Captain James Cook. Such “boards” were used to ride upon waves close to shore in an activity that came to be known as “surfing,” which was performed in the standing position. More recently, modern “surf-boards” have been combined with long-shafted paddles to create a recreational activity or sport called “paddle-boarding” or, more specifically, “Stand-up Paddle Boarding.” (The origin of the designation “stand-up” is unclear since there is no board-type device which allows one to paddle while sitting down, thereby necessitating a distinction. Also, the use of the term “boarding” is slang apparently intended to reference an activity performed with a board-type of device, e.g., snow-board, wake-board, body-board, etc.). 
         [0006]    In general, the construction of so-called “paddle-boards” is substantively similar to that of modern surfboards with the earliest paddle-boards constructed as simply longer, thicker and in some cases wider (and therefore more buoyant) versions of ordinary surfboards. The contemporary paddle-board reflects man&#39;s continued fascination with and interest in being on the water upon a relatively small “board” that is portable, relatively easy to operate and which is powered by human effort and therefore suitable as a form of personal (or individual) recreation and exercise. 
         [0007]    Relative to the modern surfboard, the addition of a long-shafted paddle suitable for use in the standing position comes as an apparent answer to dissatisfaction with the limitations of the traditional surfboard in terms of comfort, body positioning, and the use of the human body as an engine of propulsion. As per its often used name, “stand-up paddle-board,” the modern paddle-board liberates the user from having to lay down prone on the board, where visibility and comfort are limited, and from being forced to use arms and legs to paddle in the fashion of a turtle, with poor efficiency and a highly restricted amount of actual propulsion in terms of the distance-covered, propulsion speed relative to the user effort required. In contrast, the paddle-board enables the use of a more efficient paddle than users&#39; hands and feet: namely, an actual or “real” paddle with a relatively large, propulsion-maximizing blade; it also enables the user to leverage (albeit, inefficiently) his/her own body weight to produce more powerful paddle strokes; and places the user in a standing position where he/she obtains a better visual vantage to survey and with which to interact more responsively with the aquatic environment. For these reasons, the advent of the modern paddle-board has attracted great interest and, due to its ease-of-use and comfort characteristics, has drawn growing numbers of people into the water on these stand-up surf-type boards. 
         [0008]    Surfboard and Paddle-Board Locomotion 
         [0009]    For all of the advantages paddle-boards offer over surfboards as a personal water craft, photographs of paddle-board users reveal surprising but serious deficiencies in their design relative to their utilization of the human body as an engine of propulsion. The first of these is the use of the upper body limbs—the arms and hands—to produce propulsion or, to put it in biomechanical perspective, locomotion. Locomotion is genetically engineered into the design of the human body as a function of the lower body, specifically the legs and feet. The muscles, bones and joints of human legs and feet are specifically designed to carry and balance the human body during movement and to power human locomotion for both travel and the whole range of movements in which human beings engage during the normal activities of daily living. 
         [0010]    As with its predecessor, the surfboard, contemporary paddle-boarding (referring to the activity of operating a stand up paddle-board) reassigns the function of locomotion to the hands and arms which, instead of serving as biological paddles as they do with surfers and swimmers, are given actual paddles to hold, operate and row with. Using a paddle thus effectively transfers the natural locomotive function of the lower body (for which the lower body is designed) to the upper body, giving the muscles, bones and joints of the hands, arms, chest, back and upper body a workload that is poorly matched to human anatomy. The inefficiency in this reallocation of locomotive function from lower to upper body is hence only a modest improvement over the traditional surfboard. 
         [0011]    Human Biomechanics 
         [0012]    Understanding the human biomechanics of paddling a large surfboard-type of device is easily accomplished by observing people engaged in paddle-boarding, from beginners to seasoned or highly experienced “experts.” From such observation, a number of pertinent facts become readily apparent. 
         [0013]    Photographs of “paddle-boarders” (referring to people operating paddle-boards) obtained from the promotional materials of retailers typically show a person standing with feet apart (and often positioned near the side-edges of the board) in a straddle stance, leaning forward and at the same time laterally in order to pull a paddle through the water on either the left or right of the paddle-board. Pulling and leveraging the paddle through the water while, at the same time, balancing oneself on the board on the unsteady surface of the water seems to virtually require maintaining an awkward straddle stance and using only the upper body to add weight to the paddling effort. As we shall presently demonstrate, this arrangement results in an inefficient harnessing of human effort and energy, commensurately low propulsion power, and limitations on achievable speed and distance as functions of user fatigue. 
         [0014]    Biomechanical Inefficiency of Stand-Up Paddling 
         [0015]    Regarding efficiency, paddling a paddle-board requires two hands on a paddle and two arms exerting the biomechanical effort required to execute a paddle-stroke. Paddling in a standing position also recruits and significantly engages the muscles of the chest, neck and abdomen, as the user twists his/her body to the right or left to pull the paddle from its entry-point in the water ahead of the user to its exit—point behind the user. From the beginning of the paddle stroke, where the user is typically leaning forward to project the paddle toward its water entry-point, to the end of the paddle-stroke where the user&#39;s upper body is twisted away from the center of his/her body toward the paddle, the lower body and specifically the muscles bones and joints of the legs, ankles and feet, are additionally recruited for the purpose of balancing the user through, and leveraging body weight into, the paddle-stroke. A single paddle stroke thus recruits the main musculature of the arms and torso for primary power-generation while also engaging the main muscles of the lower body for support and balance. The net result is a single paddle stroke of modest propulsive power which moves the paddle-board forward but also, at the same time, laterally—as an unintended consequence of paddling on either the right or left side—movement which must later be corrected by paddling on the opposite side of the board. Hence, paddle-board propulsion is generated by the user executing a series of paddle-strokes, typically consisting of 3 to 5 strokes on one side followed by a similar number of strokes on the other side. 
         [0016]    As a source of propulsion-power, stand-up paddling is limited by the excess and consequently fatiguing demands it places on the human body relative to the amount of propulsion achieved. The effect on paddle-board operators is commonly manifest in (a) shortened paddling sessions, wherein users execute a series of paddle strokes and then rest before re-commencing; (b) effort inhibition, in which users paddle slowly and infrequently (and hence move slowly and only over a short distance) due to perceived excess effort; and (c) in the awkward, frozen and hence additionally fatiguing straddle stance, which surreptitiously recruits muscles for balance-maintenance and weight leverage during paddling, thereby draining additional human energy. 
         [0017]    The paddleboard that is the subject of this patent application remedies many of the biomechanics inefficiencies of stand-up paddle-boarding. Of first importance is the fact that propulsion is generated not by the two-handed pulling of hand-held paddles, but by the single, natural rear-ward movement of the user&#39;s leg and foot atop an unobtrusive footpad which traverses from front to back (and from back to front on the return stroke) in a motion that simulates the sliding and gliding of cross-country skiing Through the slot-tracks which run all the way through the board, each of two foot pads are directly connected to pivoting paddle blades which, on the propulsion back-stroke, automatically swivel into a position of maximum resistance at a nominal vertical angle of 90 degrees (relative to the horizontal plane of the board) and move directly against the water; and on the forward (or return) stroke, pivots to the angle of least resistance, at nominal 0 degree angle, allowing a nearly effortless recovery stroke. This direct-drive feature means that, in the propulsion stroke of the locomotion cycle, virtually all of the of the user&#39;s energy is transferred from the foot-pad on the top of the board directly to right and left paddles below, with little if any energy loss such as occurs with indirect drive mechanisms like that seen in U.S. Pat. No. 5,368,507. 
         [0018]    Of greatest importance in the design of the present invention is the biomechanically appropriate and efficient use of human body to power propulsion exploiting the natural locomotive function of the lower body, comprising the muscles of the legs, feet, hips and buttocks. The higher efficiency and effectiveness of locomotive power generated by the lower body owes to the fact that (a) these bones and muscles groups are larger and designed to carry the full weight of the body; (b) the assistive interaction of lower body components with gravity; and (c) the fact that the human body is easily capable of extended periods of locomotion as lower body muscle do not easily fatigue. Relative to (b) above, gravity provides assistance in the down and/or backward stroke of the legs, so that little energy is expended whilst the weight of the body, being perched above the legs is also easily and naturally added to leg-strokes motions. Hence, energy used in gravity-resistance effort in the leg-stroke is expended primarily on the up or forward stroke. 
         [0019]    In the user&#39;s first and beginners-level experience with the paddleboard, it will be important to learn how to maintain balance. A handle is thus provided to be held as the user slides his/her feet back and forth on the foot-pads provides balance-stability and requires little additional expenditure of user energy. With experience the handle may or may not be used. In any case, unlike a conventional paddle-board, which requires the operator to assume and maintain a straddle-stance position during paddling, the present invention enables the user to move and indeed, requires regular, rhythmical movement of the legs, thus avoiding the fatigue caused by the frozen straddle-stance used in typical paddle-boarding. 
         [0020]    The present invention is not the first floatation device aiming to harness the energy of the lower body for provide power for propulsion. U.S. Pat. No. 5,368,507 describes a paddle-floatation device which also uses the legs for power to produce propulsion. The device described in U.S. Pat. No. 5,368,507, however, requires the user to assume a prone position that makes leg-generated propulsion inefficient, more difficult and, as a practical means of propulsion, ineffective and exhausting for the user. For example, the device described in U.S. Pat. No. 5,368,507 places the legs in contact with the water and thereby creates resistance or “drag.” The prone position required by this device also forfeits the substantial benefits and considerable energy savings of gravity-assistance in producing power in the down and/or backward part of the leg-stroke of a person standing upright, as when using the present invention. Additionally, the leg-stroke applied against the pedals is simultaneously applied against the water which provides resistance against both the paddle and the legs and feet. Finally, in using the subject device of U.S. Pat. No. 5,368,507, the body of the user will be frozen in the prone position and completely deprived on the dual benefits of movement on the device (which reduces stress and fatigue) and the elevated, standing vantage point offering 360 degrees of view. 
         [0021]    The present invention is the only board-type floatation device, operated in the upright and walking position, which efficiently harnesses the lower body as an engine of propulsion. Relative to human anatomy, human males generally enjoy a substantial genetic advantage over females in upper-body strength. Where lower-body strength is concerned, however, gender differences in strength are far smaller. The present invention provides a lower-body propulsion system will therefore tend to have an equalizing effect on the propulsive power generated by men versus women. This could foreseeably result in recreational environment in which men and women are more equally represented, as with bicycling. The biomechanics of harnessing the lower-body as an engine of propulsion also favor children who also have less upper-body strength. Hence, it is conceivable that water-walking board will be become a shared recreational activity of families and users of multiple generations. 
         [0022]    Finally, lower body aerobic exercise is the exercise people most recognize the need for and therefore most seek. It is also the exercise most recommended for its health enhancement, rehabilitation and health maintenance benefits by medical professionals. The health benefits of exercising the lower body affect virtually every bodily system from the bones and muscles to the cardiovascular and endocrine systems. The proven health maintenance and prophylactic benefits of lower body exercise have been clinically demonstrated in promoting fitness and proportionate body weight and in the prevention of type II diabetes, cardiovascular diseases of all kinds, arthritis and even mental health. By assigning propulsion power-generation to the lower body and thereby leveraging the natural biomechanics of walking, the Water-Walker Board provides a highly optimized fit for a personal water craft designed for recreational pleasure, fitness, health prophylaxis, health enhancement and fun across genders, cultures and generations. 
       SUMMARY 
       [0023]    In accordance with the present invention is described are several apparatus embodiments and methods of use for a watercraft paddleboard primarily propelled by means of reciprocating propulsion mechanisms driven by the leg and foot motion of the user. 
     
    
     
       DRAWING FIGURES 
         [0024]      FIG. 1 . Paddleboard top, side and bottom view 
           [0025]      FIG. 2 . Propulsion mechanism with paddle 
           [0026]      FIG. 3 . Four paddles embodiments
       a. Solid thrust face with horizontal pivot   b. Two solid thrust faces pivot on center vertical pivot   c. Shutter valve   d. Horizontal louvers         
           [0031]      FIG. 4  Force multiplier
       a. Forward no thrust position   b. Rearward motion for thrust       
 
           [0034]      FIG. 5 . Seated propulsion
       a. Foot pad in retracted position for no thrust   b. Foot pad in extended position for thrust         
       
    
    
     REFERENCE NUMERALS IN DRAWINGS 
       [0000]    
       
         
           
               100  Paddleboard 
               101  Paddleboard propulsion slot 
               201  Foot pad 
               203  Foot pad connecting fin 
               204  Propulsion paddle swivel 
               205  Propulsion paddle 
               300  Handle 
               301  Handle support mount 
               304  Steering rudder 
               401  Seat 
               403  Foot peddle support 
               502  Large pulley 
               503  Small pulley 
               504  Foot pad cable 
               505  Propulsion cable 
           
         
       
     
       DESCRIPTION 
     Preferred Embodiment 
       [0052]    In typical operation, the user places each foot onto said foot pad  201  as shown in  FIG. 1  and reciprocates leg/foot motion in an alternating manner, similar to that of a Nordic cross country skier, thereby causing each propulsion unit in turn to move forward and backward. Depending on the paddle design utilized as per  FIG. 3 , propulsion thrust is generated to motivate said paddleboard forward as the foot pad is moved rearward thereby causing said paddle to swivel such that the orientation face of said paddle is vertical and normal to the direction of travel. Conversely, while said paddle is moved forward, motion against the water causes it to swivel upward into a horizontal orientation thereby presenting minimal resistance. Steering direction may be effected in proportion to the power expended against each paddle over a unit of time as with a conventional paddle; that is more power exerted against the right paddle directs said paddleboard to steer leftward and vice versa. 
         [0053]    Referring to  FIG. 1 , a primary embodiment includes a paddleboard watercraft resembling a conventional paddleboard  100  incorporating a pair of parallel, longitudinally oriented slots  101  through said paddleboard and extending in length as determined to conveniently accommodate the stride length of a user. 
         [0054]    Referring to  FIG. 2 , a propulsion mechanism assembly is comprised of a foot pad  201 , a fin  203  that supports connection to a thrust propulsion paddle  205  by means of a swivel joint  204 . As shown, the right side propulsion assembly illustrates said paddle in a horizontal orientation forward while the left side propulsion assembly illustrates said paddle in the downward, vertical thrusting position. Said functional components including said foot pad  201 , fin  203  and the none-rotating part of swivel joint  204  can be manufactured conveniently as a one part mold, or as individually fastened components. 
         [0055]    Said foot pad  201  is designed to support the entire weight of a user. Low friction glide material or rollers may be utilized to minimize friction with the top surface of said paddleboard  100  as said foot pad is driven in a reciprocating manner longitudinally by the action of the user&#39;s leg/foot. Said fin  203  is designed to maintain smooth linear tracking within said slot and provide a bearing surface of said propulsion assembly within said slot  101 . 
         [0056]      FIG. 3  illustrates four different paddle embodiments. In each of these embodiments, said paddle may be restrained to the vertical thrusting position by means of a vertical support or by limiting the rotation angle within said swivel. 
         [0057]      FIG. 3   a  provides a solid thrust surface designed with a horizontal swivel. One disadvantage of the embodiment of 3a is that propulsive thrust is not produced until the paddle is rotated from its horizontal to vertical position thereby requiring the foot pad to travel a distance approximately the distance of the arc length of the paddle as it swings down from its horizontal to vertical position and is proportional to the length of said paddle thereby wasting stroke length before engaging thrust against the water. 
         [0058]      FIG. 3   b  provides a solid thrust surface designed with a vertical swivel. This embodiment enables a longer and narrower paddle face aspect and thereby reduces the foot pad travel distance before producing thrust. A disadvantage is that an additional horizontal swivel is required in order to allow said paddle to swing to a horizontal orientation as it may be moved into a parking position optimally located at the forward end of said slot  101 . 
         [0059]      FIG. 3   c  provides a shutter type one way valve. This embodiment is designed such that water may flow through said valve unimpeded in one direction whilst blocking flow in the opposite direction of movement and thereby producing thrust. In such a design, said paddle could be fixed with its face oriented normal toward the direction of travel in a nominal vertical orientation would and thus not require said paddle to swivel into a nominal horizontal orientation while the paddle is moving in the forward stroke. Said check valve design could be implemented by a number of means including a set of elastomeric hinged shutter petals arranged in circular or rectilinear arrays within and supported by a paddle frame. This embodiment also requires an additional swivel in order to pivot horizontally when moved into said parking position. 
         [0060]      FIG. 3   d  provides a set of horizontally pivoting louver panels that rotate downward to vertical thrusting position. Since the vertical dimension of each louver is minimized, the travel distance of said foot pad is proportionally reduced to effect propulsion thrust. This embodiment also requires an additional swivel in order to pivot horizontally when moved into said parking position. 
         [0061]    The size and aspect of a paddle dimensions can be altered to accommodate the user&#39;s physical ability to exert thrusting power as proportional to said paddle area. 
         [0062]    In order to increase propulsion given the limited user stride distance, an additional embodiment incorporates a force multiplier mechanism assembly  500  mounted within said slot  101 . Said force multiplier provides a ratiometric force advantage to increase the speed, distance and thereby thrust power of said propulsion paddle  205 . As illustrated in FIG.  4 ., said force multiplier includes a set of pulleys and cables which attach to said foot pad and said paddle mechanisms. A large pulley  502  and a small pulley  503  are mounted at each end of said housing  501 . Said large and small pulleys can be manufactured together on a common spindle as convenient and rotate together accordingly. A foot pad cable  504  is looped around each small pulley  503  and attaches to said foot pad  201 . A propulsion cable  505  is likewise looped around each large pulley and attaches to said paddle  205 . Therefore, as said footpad  201  is translated in a reciprocating manner, the attached propulsion paddle  205  is driven to translate according to the ratio of diameters of said pulleys  502  and  503 ; i.e., if pulley  502  is twice the diameter of pulley  503 , said paddle will be driven to translate twice as fast and cover twice the distance of the motivating foot pad thereby producing twice the propulsive power. Beneficially and likewise, said paddle returns with minimal resistance to its forward position twice as fast in concert with said foot pad travel. Said force multiplier components may be assembled within a housing  501  as a module to enable removal and replacement within said slot, or be permanently installed within said paddleboard  100 . 
         [0063]    Direction of said paddle motion depends on selective fastening or connection of said foot pads or said propulsion paddle swivel with the loop side of its associated cable contained within said force multiplier. A means to selectively control direction can thereby be implemented by means of an operator switch located on said paddleboard or on said handles to select the appropriate cable loop connection and also re-orient the direction of said paddle in order to effect propulsive thrust. 
         [0064]    In an additional embodiment, a handle  300  as shown in  FIG. 1  may be conveniently attached to said paddleboard  100  to provide the user with a means to assist in keeping balance on said paddleboard. Said handle may be designed in various shapes as convenient, and may be attached to said paddleboard by a handle mount  301  designed to be inserted into mounting holes of said paddleboard. Said handle and handle mount may incorporate the means, such as handle adjustment clamps to lock telescoping height adjustment and swivel and lock pins to allow said handle to be positioned in a nominally vertical position or stowed downward horizontally on the deck of said paddleboard. 
         [0065]    In yet another embodiment, said handle mount  301  may incorporate a steering rudder protruding downward to thereby connecting to said handle  300  to enable steering of said paddleboard by the user. 
         [0066]    In yet another embodiment, said propulsion mechanism includes the means to adjust the friction of movement and/or the ability to lock said propulsion mechanism to a position within said slot as desired to enhance use of said paddleboard when surfing are beaching said paddleboard. 
         [0067]    In yet another embodiment, said propulsion mechanisms may be stowed in a protective park position at the forward end of said slots with said paddle in a nominal horizontal orientation, held in place by a feature molded or attached to the bottom of said paddleboard as convenient. 
         [0068]    In yet another embodiment, said slots  101  may be oriented longitudinally at an angle skewed from parallel to provide a more advantageous biomechanical posture for performance users thereby allowing leg/foot motion to diverge while thrusting rearward. 
         [0069]    The implementation of divergent slots can be designed to be adjustable over a range of angles or with specific angles as suitably chosen by the user. In the case of divergent slots, each said foot pad necessarily include means to allow the user&#39;s foot to rotate to accommodate the divergent motion by means such as elastomeric compliance or by means of a rotating support pad. 
         [0070]    In yet a further embodiment said paddleboard  100  may incorporate a plurality of pairs of slots the angles between said slot pair may be set at different angles diverging rearward according to user selection for biomechanical leg thrust angle and in a manner to allow a pair of said propulsion assemblies to be installed as convenient. 
         [0071]    It yet another embodiment as shown in FIG.  5 ., said paddleboard  100  may incorporate a seat assembly  401  to enable the user to propel said paddleboard while in a seated, face forward posture utilizing the same or adapted said propulsion assembly. Said seated system incorporates a seat assembly  401 , foot peddle assembly  403  and utilize a mechanical system similar to the force multiplier embodiment previously described. Said seated position system is designed to include a part of the means to enable said propulsion assembly  200  to move backward as the user extends his leg forward in a biomechanically natural and advantageous manner. Said seat assembly  401  can include a cable pulley installed with a finlike structure that extend into and locks within said slots  101  thereby enabling the seat position to be adjusted to the user accordingly. 
         [0072]    Materials and techniques for fabrication of the apparatus includes a number of conventional options as determined by design to optimize tradeoff factors such as capital costs, performance, efficiency, size, deployment strategies, configuration, environmental considerations, etc. 
         [0073]    While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not of limitation. Likewise, the various diagrams may depict an example architectural or other configuration of the invention, which is done to aid in the understanding of the features and functionality that can be included in the invention. The invention is not restricted to the illustrated example architectures or configurations, but can be implemented using a variety of alternative architectures and configurations. Additionally, although the invention is described above in terms of various exemplary embodiments and implementations, it should be understood that the various features and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in some combination, to one or more of the other embodiments of the invention, whether or not such embodiments are described and whether or not such features are presented as being a part of a described embodiment. Thus the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments. 
         [0074]    Terms and phrases used in this document, and variations thereof, unless otherwise expressly stated, should be construed as open ended as opposed to limiting. As examples of the foregoing: the term “including” should be read to mean “including, without limitation” or the like; the term “example” is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof; and adjectives such as “conventional”, “traditional”, “normal”, “standard”, “known” and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass conventional, traditional, normal, or standard technologies that may be available or known nor at any time in the future. Likewise, a group of items linked with the conjunction “and” should not be read as requiring that each and every one of those items be present in the grouping, but rather should be read as “and/or” unless expressly stated otherwise. Similarly, a group of items linked with the conjunction “or” should not be read as requiring mutual exclusivity among that group, but rather should also be read as “and/or” unless expressly stated otherwise. Furthermore, although items, elements or components of the invention may be described or claimed in the singular, the plural is contemplated to be within the scope thereof unless limitation to the singular is explicitly stated. The presence of broadening words and phrases such as “one or more”, “at least”, “but not limited to” or other like phrases in some instances shall not be read to mean that the narrower case is intended or required in instances where such broadening phrases may be absent.