Abstract:
A pedal propulsion device for use on a small watercraft, having a lightweight portable frame with integral foot-engagement cranks. A propeller and rudder assembly driven by the foot cranks automatically will adjust for obstacles within and below the water, while maintaining direct drive by utilizing a depth stabilizer assembly extending from the support frame.

Description:
This application claims the benefit of U.S. Provisional Application No. 61/913,356, filed Dec. 8, 2013. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The primary way to propel and control small unpowered watercraft is with paddles or oar. These devices use the arms and upper body to do the heavy work of propelling a boat through the water, as well as controlling the direction of the craft. The more appropriate members of the body for locomotion are the legs, which are stronger and process greater endurance. 
     Both paddles and oars require skill and practice to use and can be frustrating and confusing to try to put to use efficiently, especially for beginners. Both are not very intuitive in operation. Paddling requires switching from side to side to keep a straight track, and even so may still result in a very zigzag course. 
     Rowing also has other drawbacks, such as the user must sit backwards to the direction of travel and must look over the shoulder or the corner of their eye to see where he is going. 
     This invention relates to specifically to a pedal propulsion system for powering small lightweight watercraft. The system has a portable support frame, which is easily adaptable and provides for integrated pedal powering mechanism to drive and steer the craft. 
     2. Description of Prior Art 
     Prior art devices of this nature can be seen for example in U.S. Pat. Nos. 5,413,066, 7,530,867 B2, and 8,342,897 B2. 
     In U.S. Pat. No. 5,413,066, a pedal powered pond boat can be seen having propulsion systems with a set of pedals that drives a propeller assembly, which can move up upon contact with an obstacle in the water. 
     U.S. Pat. No. 7,530,867 is directed to a portable canoe propulsion system having a pedal powered crank and gear box for a propeller on a driveshaft that can be moved from a operable position to a non-operable position. 
     Finally, in U.S. Pat. No. 8,342,897 a pedal propulsion system is claimed having a pedal driven crankshaft and propeller in communication therewith. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the pedal prop of the invention. 
         FIG. 2  is an enlarged partial perspective view thereof. 
         FIG. 3  is an enlarged partial perspective view of a depth setter stabilizer assembly of the invention. 
         FIG. 4  is an exploded perspective view of the gear box and mount of the invention. 
         FIG. 5  is an enlarged partial side elevational view of the rudder guard and propeller. 
     
    
    
     SUMMARY OF THE INVENTION 
     The pedal prop is an add-on device for small unpowered watercraft, both rigid and inflatable, such as kayaks, canoes, Jon boats and dinghies, that enables the user to pedal to power a propeller for propulsion with an integral rudder for directional control rather than using paddle or oars. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The pedal prop of the invention is composed of multiple primary components: frame, chain box, pedal input crank assembly and drive tube. 
     A frame  10  is rectangular in form and can be made of several different materials, including aluminum tubing being one of the best. Square, rectangular or round tubing can be fabricated into the frame  10  by using any number of ways to fasten the tubing together at the corners. Bolt gussets, ‘L’ brackets  11  or some other right angle tube connector can be used to form the corners. Bending the tubing to a right angle is also possible. 
     A chain box  12  is composed of two plates, the outside plate  13  and an inside plate  14  of the same size and position in spaced opposition to one another. The plates are bolted together with appropriate spacers to set the distance between them. Each of the plates  13  and  14  has an opening A to accommodate flange bearings  15  for a crankshaft  16  that runs through both plates perpendicular thereto. The crankshaft  16  has a roller chain sprocket  19  secured thereto between the respective plates  13  and  14 . 
     A pedal input crank assembly  21  extends from the crankshaft  16  having two oppositely disposed spaced offset foot engagement cranks  22  and  23  on a support shaft rotatably secured to the frame  10  by a bearing fitting  22 A, as will be understood by those skilled in the art, and best seen in  FIG. 1  of the drawings. 
     A small right angled gear box  18  is mounted to the outside plate  13  of the chain box  12 . The gear box  18  will not be rigidly attached but able to rotate 360 degrees around the input shaft which is perpendicular to the plates. An output shaft  18 A of the gear box  18  is parallel with the plates  13  and  14  and outside the chain box  12 , as best seen in  FIG. 2  of the drawings. A second opening outside plate  13 , which has a diameter that matches the outside edge of a bolt hole pattern within the input face of the gear box  18 . It will be seen that when bolts B are placed in the input face of the gear box  18 , the gear box can rotate through 360 degrees. To prevent the gear box from coming in contact with the plate, a thin stainless steel fender washer W which is of a slightly larger diameter than that of the aperture A 2  is positioned between the gear box  18 . 
     The washer&#39;s W center hole C accommodates the input shaft of the gear box and the bolt hold pattern for the gear box  18  is transferred to the washer W, and the clearance holes are drilled in the fender washer W for the mounting bolts B for the gear box  18 . A second fender washer W 2  is identical to the first and is placed on the other side of the outside plate  13  between the respective inside and outside plates  14  and  13 , and the mounting bolts B are passed through the clearance holes of the washer WA through spacers S which are the same thickness as the outside plate  13  (one on each bolt) through the opening A 2  in the plate  13 , through the clearance holes of the washers W and secured into the input face of the gear box  18 . The bolts B are tightened enough to press both the washers WA and W 2  on the opposite sides of the respective outside plate  13 , but the spacers between the washers prevent over-tightening, which would prevent the gear box  18  from rotating. It will be evident that this arrangement allows the gear box  18  to rotate, as will be required during use and discussed and described in greater detail hereinafter. 
     A second smaller roller chain sprocket  19 A shown in broken lines in  FIG. 1  of the drawings, is mounted on the input shaft of the gear box  18 . A roller chain  20  connects the two roller chains sprockets  19  and  19 A transferring rotational output of the crank assembly  21  to the input shaft of the gear box  18 , as will be well understood by those skilled in the art. 
     Referring now to  FIGS. 1 and 2  of the drawings, a drive tube  24  can be seen, which is used to transfer rotational gear box  18  power output to a propeller  25  at the end of the drive tube  24 , which also supports a rudder  26  which steers the watercraft WC and a propeller guard  27  which also protects the rudder  26 . The drive tube  24  is attached to the output end of the gear box  18 , utilizing a two-piece clamp-on shaft collar  24 A which has been bolted to the output side of the gear box  18 . 
     A drive shaft  28  is accordingly supported inside the drive tube  24  by custom-made delrin (plastic) bushings  29  therein at each end of the drive tube  24  and one in the center. The bushings  29  are held in position in the drive tube  24  by a fastener passing through the wall of the drive tube  24  and into the respective bushings  29 , shown in broken lines in  FIG. 2  of the drawings. 
     The drive tube  24  (as noted) supports propeller guard  27  as best seen in  FIG. 5  of the drawings, which is formed from a thin aluminum rod bent into a compound shape. A rod bottom  27 A of the guard  27  has a gentle slope going from a forward point on the drive tube  24  towards the propeller  25 , so it will easily ride over obstacles (not shown) and protect the propeller  25 . The guard  27  then goes under the propeller  25  and bends upwardly to go vertically at  27 B just behind the propeller  25 . Once the guard is above the top of the propeller  25 , it is bent over the top and then bends downwardly until it reaches the top of the drive tube  24  where it is parallel to the drive tube so it can be fastened to the drive tube  24  at  30 . 
     The rudder  26  is constructed of suitable material like polycarbonate (plastic) sheet and is positioned to the rear of the propeller  25  on the vertical section of the propeller guard  27 B. 
     The rudder  26  is moveably secured to the propeller guard section  27 B by a plurality of vertically spaced hinge brackets  31 , pivotally extending around the guard section  27 B and secured to a rudder bar  32  along the rudder edge and extending upwardly there beyond at  32 A. 
     A tiller rod  33  is pivotally attached to the upper bar portion  32 A by a threaded spacer  34  and an interior linking eyelet in cleves assembly  35 A positioned thereon. 
     It will be seen that the tiller rod  33  extends forward through a guide fitting  33 A on the drive tube  24  as best seen in  FIG. 2  of the drawings, so as to position the free end of the tiller rod  33  for engagement by a user as would be positioned (not shown) in the watercraft WC. 
     Referring now to  FIGS. 1, 2 and 3  of the drawings, a depth stabilizer assembly  35  can be seen, which controls and limits the maximum vertical travel of the drive tube  24  and attached rudder  26  and propeller guard  27 , when encountering an object in the water, as well as providing manual repositioning thereof. A control tube  36  is pivotally secured at one end to the drive tube  24  by a clamp  37  and it is oppositely disposed end by a spacer linkage  38  to an adjustable arm  39 , which in turn is adjustably secured to the end of a support bracket  40  extending at right angles therefrom by a T-handled fitting  41 , as best seen in  FIG. 3  of the drawing. 
     An adjustable cord  42  extends from the clamp  37  up through a mounting plate  43  secured to and extending from the free end of the arm  39  which sets the operating depth of the depth setter stabilizer by a cord clip  42 A. A drive tube retainment clip  44  is positioned on the end of the plate  43 , which allows for manual raising and retaining of the drive tube  24  in the retaining clip  44  utilizing the cord  42 , if and when required. 
     The support frame bracket  40  extends in space parallel alignment along the end portion of the support frame  10  and is secured thereto by fasteners and spacers assemblies  38 A, as will be understood by those skilled in the art. 
     In operation, the pedal prop of the invention is positioned within a suitable watercraft WC as seen partially in  FIGS. 1 and 2  of the drawings, with the end portion  10 A of the support frame  10  being positioned just in back where a seat (not shown) would be with the crank assembly  21  in space relation thereto in the intended direction of travel. 
     The drive tube  24  will therefore be outside of the watercraft along side in parallel offset relation to its center axis. 
     It will therefore be seen that the depth of the propeller  25  in the water is determined by the depth stabilizer assembly  35 , which limits the travel of the drive tube  24 , as herein before described. It will be evident therefore that once an object in the water (not shown) is engaged by the propeller guard  27 , that the drive tube  24  and its integrated attached rudder  26  and propeller  25  will be effectively move upwardly in a controlled stabilized manner by the depth stabilizer assembly  35 , with the gear box  18  being able to effectively pivot within its mounting configuration as described above. Once the object has passed, then the drive tube  24  and its integrated effective elements will automatically drop down re-engaging the propeller  25 , and more importantly thereby effectively protecting the rudder  26  and propeller  25  assemblies from damage. 
     It will also be seen that the use of the tiller rod  33  provides for safe and effective movement of the rudder  26  remotely within the integrated propulsion and directional input assembly as described. 
     As noted in use, the operator (not shown) sits down with his or her back against the back member of the frame  10 A and their feet on the crank assembly  21  foot engagement cranks  22  and  23  and by peddling causes the propeller  25  to rotate and propel the watercraft WC. The direction of control is achieved by controlling the rudder with the tiller rod  33  as noted. By peddling backwards, the watercraft WC can effectively go in reverse. The propeller guard  27  protects the propeller  25  and the rudder  26  from underwater obstacles and because of the hereinbefore mounting of the gear box  18 , the drive tube and its supported elements rises up and pass over obstacles and returns to its operational depth as set by cord  42 . The watercraft WC can also be beached without any manual action by raising the drive tube and the propeller  30  to avoid damage to it. 
     It will thus be seen that a new and novel pedal prop assembly has been illustrated and described, and it will be apparent to those skilled in the art that various changes and modifications may be made thereto without departing from the spirit of the invention.