Patent Publication Number: US-11034423-B2

Title: Pedal drive system for watercraft

Description:
CROSS-REFERENCE TO RELATED PATENT DOCUMENTS 
     This patent application claims the benefit of priority of U.S. Provisional Application No. 62/710,698, entitled “Pedal Drive System for Watercraft,” filed Feb. 26, 2018, which are hereby incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to watercrafts such as kayaks, canoes, paddle boards, or the like, and, more particularly, to a pedal drive system for a watercraft for propelling the watercraft based on mechanical input provided by a user by means of a pedal arrangement. 
     BACKGROUND 
     Various types of boats have been known and used by users since long time. Most of these boats have used sailing or some other artificial form of propulsion. Human-powered boats have also been known for thousands of years, and have generally used oars. Human-powered watercrafts are used on a large scale in coastal areas, and also are often used for exercise. The exercise results from the user employing his or her physical strength to provide motive power for the watercraft. Human-powered watercrafts are used for transportation, fishing, watersports activities, or the like. Examples of the human-powered watercrafts include, but are not limited to, kayaks, rowboats, and pedal boats. These all carry additional benefits, in that they provide the user with physical exercise. 
     Various drive systems are known in the art for providing motive power to a watercraft, such as a kayak or a canoe. In some examples, a pedal-powered drive system is provided as an alternative to a watercraft with a gas-powered drive system or an oar-powered drive system. An advantage of pedal-powered drive systems over gas-powered drive system is the pedal-powered drive systems are silent and more environmentally friendly than a gas-powered drive system. In addition, the watercraft with the pedal-powered drive systems can be taken into water with rock hazards without the fear of destroying the propeller, such as with a gas-powered motor. Compared to the oar-powered drive systems, the pedal-powered drive systems allow the user to use his or her legs to power the watercraft, which provides a mechanical advantage that allows for reaching greater speeds in water compared to using an arm-powered oar. 
     While the existing pedal-powered drive systems provide a number of advantages, they are also associated with a number of disadvantages. For example, various materials of a pedal drive system are not corrosion proof and degrade when they are exposed to water. Thus, the pedal drive system requires a lot of maintenance that increases the overall operating cost. Furthermore, in order to reduce the corrosion effect, the current pedal drive systems have been designed to keep water out of the mechanism in an attempt to increase drive assembly longevity. This dramatically increases the design and manufacture costs as sealing the unit becomes a primary consideration. Water ingress in these units typically leads to drive component failure through oxidation or mechanical degradation of internal components. Also, in a traditional attachment, the transfer of power from a metal drive shaft to a plastic gear would require a much larger gear assembly to resist failure. In light of the foregoing, there exists a need for a technical and more reliable solution that solves the above-mentioned problems and provides an improved pedal-powered drive system for watercraft that overcomes the disadvantages of the existing drive systems. 
     BRIEF SUMMARY 
     It is an objective of the present invention to provide a pedal drive system for a watercraft for propelling the watercraft based on mechanical input provided by a user by means of a pedal arrangement. The present invention provides the pedal drive system that transfers rotational motion from a user to a propeller of the watercraft. The propeller is disposed beneath the watercraft such as a kayak or a canoe. The pedal drive system includes an enclosure that houses a pedal mechanism. In an embodiment, the pedal mechanism incorporates a channel around the circumference of a wheel that rotates when a user operates pedals of the pedal arrangement. The channel retains a first gear that extends below the pedal mechanism where it first makes contact with a second gear. The second gear is positioned in manner in which the second gear is perpendicular to the first gear (90 degrees) and rotates from the motion imparted to it by the first gear. 
     In an embodiment, the second gear is attached to a drive shaft that extends vertically below the hull of the watercraft, and shares an axis of rotation with the second gear. The opposing end of the drive shaft retains a third gear that also shares an axis of rotation with the drive shaft and the second gear. The third gear drives a fourth gear positioned perpendicularly so that the axis of the fourth gear is parallel to the long axis of the watercraft such that the axis is oriented towards the stern of the watercraft. The fourth gear drives a second shaft which translates the drive motion to the propeller of the watercraft. 
     In an embodiment, a protective body, such as the one illustrated in the shape of a fin, is placed in front of the propeller to protect the propeller from any damage while in the water. In an embodiment, a pair of foot pegs are provided for the user to rest his or her feet when the user is not pedaling. While the drive shaft has been described in the preferred embodiment, a roller chain or band can also be used in other embodiments, without limiting the scope of the present invention. 
     Further, in an embodiment, the pedal drive system of the present invention is placed through an opening in the bottom of the watercraft and affixed to the body of the watercraft. The propeller is then attached to the drive shaft. When the user operates the pedal mechanism, the rotational force is transferred from the drive assembly through the gears to the drive shafts that rotates the propeller, thus driving the watercraft forward as well as backward. 
     These and other features and advantages along with other embodiments of the present invention will become apparent from the detailed description below, in light of the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
       The novel features which are believed to be characteristic of the present disclosure, as to its structure, organization, use and method of operation, together with further objectives and advantages thereof, will be better understood from the following drawings in which a presently preferred embodiment of the invention will now be illustrated by way of example. It is expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. Embodiments of this disclosure will now be described by way of example in association with the accompanying drawings in which: 
         FIG. 1  shows a schematic arrangement that illustrates an enclosed pedal drive system for a watercraft, in accordance with an embodiment of the present invention; 
         FIG. 2  shows a schematic arrangement that illustrates internal components of the pedal drive system, in accordance with an embodiment of the present invention; 
         FIG. 3  shows a schematic arrangement that illustrates a top view of a tri-lobe drive shaft of the pedal drive system, in accordance with an embodiment of the present invention; 
         FIG. 4  shows a schematic arrangement that illustrates a side view of the tri-lobe drive shaft, in accordance with an embodiment of the present invention; 
         FIG. 5  shows a schematic arrangement that illustrates an expanded view of the tri-lobe drive shaft, in accordance with an embodiment of the present invention; 
         FIG. 6  shows a schematic arrangement that illustrates a top view of the tri-lobe drive shaft with a gear fixed on its top, in accordance with an embodiment of the present invention; 
         FIG. 7 a    shows a schematic arrangement that illustrates a bottom perspective view of the gear and the tri-lobe drive shaft, in accordance with an embodiment of the present invention; 
         FIG. 7 b    shows a schematic arrangement that illustrates a top perspective view of the gear and the tri-lobe drive shaft, in accordance with an embodiment of the present invention; 
         FIG. 8 a    shows a schematic arrangement that illustrates an enclosed impulse drive unit of the pedal drive system, in accordance with an embodiment of the present invention; 
         FIG. 8 b    shows a schematic arrangement that illustrates internal components of the impulse drive unit, in accordance with an embodiment of the present invention; and 
         FIGS. 9 a -9 d    show schematic arrangements that illustrate a propeller locking mechanism, in accordance with an embodiment of the present invention. 
     
    
    
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description of exemplary embodiments is intended for illustration purposes only and is, therefore, not intended to necessarily limit the scope of the invention. 
     DETAILED DESCRIPTION 
     As used in the specification and claims, the singular forms “a”, “an” and “the” may also include plural references. For example, the term “an article” may include a plurality of articles. Those with ordinary skill in the art will appreciate that the elements in the Figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the Figures may be exaggerated, relative to other elements, in order to improve the understanding of the present invention. There may be additional components described in the foregoing application that are not depicted on one of the described drawings. In the event such a component is described, but not depicted in a drawing, the absence of such a drawing should not be considered as an omission of such design from the specification. 
     Before describing the present invention in detail, it should be observed that the present invention utilizes a combination of mechanical components, which constitutes a pedal drive system for a watercraft for propelling the watercraft based on mechanical input provided by a user by means of a pedal arrangement of the pedal driver system. Accordingly, the components have been represented, showing only specific details that are pertinent for an understanding of the present invention so as not to obscure the disclosure with details that will be readily apparent to those with ordinary skill in the art having the benefit of the description herein. As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention. 
     References to “one embodiment”, “an embodiment”, “another embodiment”, “yet another embodiment”, “one example”, “an example”, “another example”, “yet another example”, and so on, indicate that the embodiment(s) or example(s) so described may include a particular feature, structure, characteristic, property, element, or limitation, but that not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element or limitation. Furthermore, repeated use of the phrase “in an embodiment” does not necessarily refer to the same embodiment. 
     The words “comprising,” “having,” “containing,” and “including,” and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items or meant to be limited to only the listed item or items. 
     Techniques consistent with the present invention provide, among other features, a pedal drive system that transfers rotational motion from a user to a propeller disposed beneath a watercraft such as a kayak or canoe, thus driving the watercraft forward as well as backward. Unless stated otherwise, terms such as “first” and “second” are used to arbitrarily distinguish between the elements such terms describe. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements. While various exemplary embodiments of the disclosed system and method have been described above it should be understood that they have been presented for purposes of example only, not limitations. It is not exhaustive and does not limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practicing of the invention, without departing from the breadth or scope. 
     The pedal drive system will now be described with reference to the accompanying drawings which should be regarded as merely illustrative without restricting the scope and ambit of the disclosure. 
       FIG. 1  shows a schematic arrangement  100  that illustrates an enclosed pedal drive system for a watercraft, in accordance with an embodiment of the present invention. The pedal drive system includes an enclosure  102  that houses a pedal mechanism similarly arranged to that of a bicycle. As shown in  FIG. 1 , the schematic arrangement  100  shows a plurality of pedals such as pedals  104   a  and  104   b , a plurality of pedal cranks such as pedal cranks  106   a  and  106   b , and a see-through splash guard  108 . The pedal drive system can also include a plurality of foot pegs (not shown). 
     The pedals  104   a  and  104   b  are levers that are removably fixed to the pedal cranks  106   a  and  106   b , respectively. The pedals  104   a  and  104   b  are positioned opposite to each other as shown in  FIG. 1  and are rotatable about a pedal axis (a horizontal axis). The pedal cranks  106   a  and  106   b  are removably fixed to a shaft that fits tightly with the gear to rotate the pedal cranks  106   a  and  106   b . The pedal driver system is manually operated by a user when the user provides mechanical input through the rotation of the pedals  104   a  and  104   b.    
     Each pedal  104   a  or  104   b  has a pedal platform for supporting the user&#39;s foot and a pedal crank  106   a  or  106   b , respectively. The pedal crank  106   a  is connected at one end to the pedal platform and at the other end to the rotatable wheel (e.g., a pedal gear set). Rotation of the pedal cranks  106   a  and  106   b  due to the mechanical input received from the user&#39;s legs causes a corresponding rotation of the pedal gear set. The pedal mechanism transfers the mechanical input into rotation of a propeller  110  of the pedal driver system. A foot peg may also be provided for the user. The user can use the plurality of foot pegs to rest her feet when the user is not pedaling the pedals  104   a  and  104   b . The see-through splash guard  108  makes taking the pedal drive system out in a easy manner and gives the user a window to see into what lies below. The see-through splash guard  108  also makes it easier for the user to remove the pedal drive system from the watercraft. The pedal drive system is fully removal and easy to carry. 
       FIG. 2  shows a schematic arrangement  200  that illustrates internal components of the pedal drive system, in accordance with an embodiment of the present invention. The pedal drive system includes the rotatable wheel  202 , a first drive gear  204 , a second driver gear  206 , a first drive shaft  208 , a third drive gear  210 , a fourth drive gear  212 , and a second drive shaft  214 . The pedal drive system also includes a pedal-and-sprocket arrangement made up of the pedals  104   a  and  104   b  and the pedal cranks  106   a  and  106   b . The pedal drive system also includes the propeller  110  and a protective body  216  (such as the one illustrated in the shape of a fin). The protective body  216  is placed in front of the propeller  100  to protect it from damage while in the water. 
     In an embodiment, the pedal mechanism of the pedal drive system is realized and implemented using the components, as shown in  FIG. 2 . The pedal mechanism incorporates a channel around the circumference of the rotatable wheel  202 . The rotatable wheel  202  rotates when the user operates the pedals  104   a  and  104   b  by providing the mechanical input through her body parts, for example, by pedaling the pedals  104   a  and  104   b  using her feet. The channel retains the first drive gear  204  that extends below the pedal mechanism where the first drive gear  204  makes contact with the second drive gear  206 . The first and second drive gears  204  and  206  are positioned in a way in which the second drive gear  206  is perpendicular (90 degrees) to the first driver gear  204 , or vice-versa, and the second driver gear  206  rotates from the motion imparted to it by the first drive gear  204 . 
     In an embodiment, the second driver gear  206  is removably attached to the first drive shaft  208  that extends vertically below the hull of the watercraft, and shares an axis of rotation with the second drive gear  206 . The opposing end of the first drive shaft  208  retains the third driver gear  210  that also shares an axis of rotation with the second drive gear  206  and the first drive shaft  208 . The third drive gear  210  drives the fourth drive gear  212  that is positioned perpendicularly so that an axis of rotation of the fourth drive gear  212  is parallel to the long axis of the watercraft such that the axis is oriented towards the stern of the watercraft. The fourth drive gear  212  drives the second drive shaft  214  which transfers the drive motion (i.e., the rotational motion) to the propeller  110 . In an embodiment, the protective body  216  has been placed in front of the propeller  110  to protect it from damage when the watercraft with the pedal drive system is in the water. The protective body  216  may also facilitate steering of the watercraft based on the operation of the pedal drive system by the user. 
     In operation, the pedal drive system is placed through an opening in the bottom of the watercraft and affixed to the body of the watercraft. The propeller  110  is then attached to the second drive shaft  214 . When the user operates the pedal mechanism, the rotational force is transferred from the drive assembly through the drive gears  204 ,  206 ,  210 , and  212  to the drive shafts  208  and  214  that rotates the propeller  110 , thus driving the watercraft forward as well as backward. 
       FIG. 3  shows a schematic arrangement  300  that illustrates a top view of a tri-lobe drive shaft of the pedal drive system and  FIG. 4  shows a schematic arrangement  400  that illustrates a side view of the tri-lobe drive shaft, in accordance with an embodiment of the present invention. The tri-lobe drive shaft is the first drive shaft  208  of the pedal drive system. 
     In an embodiment, each of component interfaces, where the drive force is transferred from a metal component to a plastic component, has been designed to incorporate the tri-lobe drive shaft  208 . The tri-lobe drive shaft  208  has been designed and developed to increase the surface area of contact between the two components, in order to increase the strength of the interfaces. In a traditional attachment, the transfer of power from a metal drive shaft to a plastic drive gear generally requires a much larger gear assembly to resist failure. With a tri-lobe interface facilitated by the tri-lobe drive shaft, the present invention facilitates a much smaller gear assembly while increasing the strength of each joint across each component interface. 
     In order to incorporate standard round bearings, a tri-lobe spacer  302  has been designed and developed to interface between each shaft and bearing, such as between the tri-lobe drive shaft  208  and the bearing component  304 . This tri-lobe bearing interface  302  incorporates a shaped metal sleeve that bolts to the tri-lobe drive shaft  208  in a position between the tri-lobe drive shaft  208  and the bearing component  304 . The outer face of the tri-lobe spacer  302  is round so as to provide a proper fit to standard bearings. 
     The tri-lobe drive shaft  208  shape is profiled in a triangular pattern with constant radius corners and constant convex radius sides. This shape provides strong rotational power transfer (axially) by increasing the contact surface without the incorporation of holes or sharp corners. The tri-lobe drive shaft  208  is used at all connection points or joints within the power transfer assembly of the pedal drive system. For example, tri-lobe drive shafts (similar to the tri-lobe drive shaft  208 ) are used with a pedal axle shaft to an upper drive gear (e.g., the first drive gear  204 ), an upper second gear (e.g., the second drive gear  206 ) to a main drive shaft (e.g., the first drive shaft  208 ), a lower third gear (e.g., the third drive gear  210 ) to the main drive shaft, a lower fourth gear (e.g., the fourth drive gear  212 ) to a propeller drive shaft (e.g., the second drive shaft  214 ), the propeller drive shaft to the propeller  110 , or the like. Also, in an embodiment, the pedal drive can be made longer or shorter by changing or modifying a plurality of parts that go into the center of the pedal drive. For example, the parts, such as the enclosure  102  and the tri-lobe drive shaft  208 , may be changed or modified as per the application requirement to facilitate longer or shorter pedal drive. In other way round, the enclosure  102  and the tri-lobe drive shaft  208  may be made longer or shorter that allows to change the overall length of the pedal drive. 
     In an embodiment, the tri-lobe spacer  302  is used at all bearing locations in lower drive assembly, for example, the main drive shaft to main extrusion housing upper bearing, the main drive shaft to main extrusion housing lower bearing, the propeller drive shaft to lower housing both bearings, or the like. 
       FIG. 5  shows a schematic arrangement  500  that illustrates an expanded view of the tri-lobe drive shaft, in accordance with an embodiment of the present invention. The schematic arrangement  500  illustrates the enclosure  102  that houses the tri-lobe drive shaft  208 . After inserting the tri-lobe drive shaft  208  into the enclosure  102 , the tri-lobe spacer  302  is removably fixed around the tri-lobe drive shaft  208 . Thereafter, the bearing components  304  are removably fixed around the tri-lobe spacer  302 . Further, the second drive gear  206  is removably attached to the tri-lobe drive shaft  208  from the top by means of a screw  502 . The tri-lobe drive shaft  208  has been shown in  FIG. 6  that shows a schematic arrangement  600  for illustrating a top view of the tri-lobe drive shaft  208  with the second drive gear  206  fixed on its top. In continuation with the ongoing discussion,  FIG. 7 a    shows a schematic arrangement  700   a  that illustrates a bottom perspective view of the tri-lobe drive shaft  208  and the second drive gear  206  and  FIG. 7 b    shows a schematic arrangement  700   b  that illustrates a top perspective view of the tri-lobe drive shaft  208  and the second drive gear  206 . 
       FIG. 8 a    shows a schematic arrangement  800   a  that illustrates an enclosed impulse drive unit of the pedal drive system and  FIG. 8 b    shows a schematic arrangement  800   b  that illustrates internal components of the impulse drive unit, in accordance with an embodiment of the present invention. The pedal drive system is impulse drive powered and has been designed to allow water inside the mechanism. The incorporation of the tri-lobe drive shaft allows the use of plastic drive gears (such as the drive gears  204 ,  206 ,  210 , and  212 ), in place of metallic drive gears, and as such the internal components within the drive unit are impervious to water damage. This design detail has four significant advantages to a sealed unit. By removing the added costs associated with incorporating a sealed housing, the impulse drive unit can be designed and manufactured at a significantly reduced cost. By designing all of the components to be impervious to water damage, the long-term reliability of the impulse drive unit is increased. Allowing water to fill the internal space provides added stability in relation to resisting roll and yaw during usage by the user. The added weight of the water within the drive shell dampens roll of the watercraft and improves stability for the user. The user can flush the internal components to allow for maintenance cleaning if required. 
     In an embodiment, the impulse drive unit incorporates a filtered opening  802  at the lowest point in the assembly to allow water to fill the inner space vertically once the drive unit is installed into the drive position within the watercraft. The filtered opening  802  is designed to incorporate a small filter member that restricts the ingress of foreign material into the drive unit. The filter member is designed to filter the water as it comes into the unit and self-clean as the water exits the unit. The filter member is also designed to restrict the flow of water into and out of the unit so that once the water level within the unit is at maximum level, its flow is dampened. The filter member is designed to be removable to allow for cleaning or user replacement. A small inlet port is designed into the top of the upper shell housing allowing the unit to be flushed with clean water for periodic maintenance. Water inlet filter is positioned such that the intake port is lowest in the housing as well as protected by the lower fin assembly. 
       FIGS. 9 a -9 d    show schematic arrangements  900   a - 900   d  that illustrate a propeller locking mechanism, in accordance with an embodiment of the present invention. The impulse drive unit incorporates a unique propeller locking mechanism to allow the propeller  110  to be locked into a vertical position for drive install and removal. The propeller locking mechanism includes a pin lock mechanism that utilizes a single thin rod  902  that runs internally along the vertical length of the impulse drive unit. The rod  902  may be made up of a plastic material. An upper end of the rod  902  incorporates a push button assembly  904  that is spring loaded against the upper drive shell. This spring assembly forces the rod  902  into the most vertical position possible with the assembly to keep the opposing end from engaging with the propeller drive shaft assembly. 
     The main body extrusion is designed with a channel to hold and support the pin lock rod  902 . The opposing end of the rod  902  is positioned such that it is free of any interference with the propeller drive shaft assembly when in the upper position. When the rod  902  is lowered (depressed from top button), the bottom end of the rod  902  engages with one of two holes  906   a  and  906   b  designed into one of the drive shaft bearing spacers (such as the tri-lobe spacer  302 ) supporting the propeller drive shaft assembly. These two holes  906   a  and  906   b  are designed into the bearing spacer (such as the tri-lobe spacer  302 ) such that when engaged the propeller  110  is locked in a vertical position allowing the drive unit to be lifted through the hole  906   a  or  906   b  in the watercraft where the drive is assembled. This mechanism allows the user to orient the propeller  110  for clearance from the operating position. 
     The pedal drive presented in the present invention is impulse powered drive and is the most affordable and lightest pedal drive. The pedal drive carries like a regular kayak and requires less effort to propel. The pedal drive is light, fully removable, and easy to store. The pedal drive facilitates effortless forward and backward movement. The pedal drive may include variable gear ratio for each drive gear (such as the drive gears  204 ,  206 ,  210 , and  212 ), props and power options. The pedal drive is fully user serviceable and does not require oil or complicated maintenance. Each drive gear is water resistant and is made up of one or more plastic materials i.e., the drive gears  204 ,  206 ,  210 , and  212  are plastic gears. The materials used in the plastic gears are, in general, engineering plastics such as polyacetal (POM) and MC Nylon which is essentially polyamide resin. In addition, U-PE and PEEK can be used. The positive characteristics of the plastic gears include being lightweight, non-rusting, quiet, injection molding enabling low cost and large production, and able to operate without lubrication by mating with metal gears. The pedal drive has see-through splash guard  108  that makes it easier for the user to remove the pedal drive from the watercraft. The see-through splash guard  108  can be used by the user to lineup the propeller with the pedal driver system and the user can pull out the pedal drive system from the watercraft. In an exemplary embodiment of the present invention, the pedal drive has weight of 8.25 pounds, length of 90 cm, height of 23 cm, and thickness of 7 cm, and can easily fit with the watercraft, such as kayak having weight of 66 pounds, length of 10.4 feet, width of 36 inches, and capacity of 470 pounds, without limiting the scope of the present invention. Thus, the pedal drive of the present invention is more effective and efficient than other pedal drives that are known in the art. The pedal drive is the lightest, most affordable, most seaworthy, and versatile drive in the current market. 
     Although the present invention has been described with respect to the pedal drive system, it should be understood that the proposed pedal drive system can be formed with varying shapes and sizes, and thus the disclosure here should not be considered limited to the exemplary embodiments and processes described herein. The various dimensions may be modified to fit in specific application areas. The pedal drive system of the present invention features a high-performance encased design that is immune to water damage. All of the materials have been designed/chosen because they are tough and will not corrode or degrade in the water. This dramatically reduces wear and tear of the various components of the pedal drive system and provides a high-performance design that is both user serviceable and incredibly versatile for the retailer and end user. 
     Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention.