Patent Application
20110159751
1. Field of the Invention
This invention relates to a pedal propulsion system for powering a transportation conveyance particularly a relatively light weight water craft such as a canoe, boat and the like. The system has a portable support frame such that it is adaptable in the transportation conveyance. The support frame includes a seat for the operator to sit therein to operate the system with ease and comfort for driving the transportation conveyance.
2. Background of the Invention
Pedal propulsion systems are commonly employed for driving a boat. Most of the present propulsion systems are integrally built into the boat so that it is not removable from the latter. Thus it is particularly not convenient to transport the boat having a built-in pedal propulsion system.
In a pedal propulsion system, pedals mounted to a rotary shaft of a sprocket are operative to rotate the sprocket which is coupled by a continuous chain or a gear assembly for delivering the power to the driving device of a transportation conveyance. The sprocket has teeth formed on its peripheral circular edge to engage with links or loops in the chain or alternatively with a gear assembly which also engages with a toothed drive wheel to provide the rotational movement for the transportation conveyance. When a pedal propulsion system is used in a water craft for driving its propeller, the rotational movement of the toothed drive wheel must be converted for 90 degrees in order to rotate the propeller of the water craft. Alternatively, a gear assembly or similar mechanical linkage is employed to change the rotational movement of the sprocket for 90 degrees for the same purpose. The efficiency of a gear assembly or mechanical linkage is low due to friction and mechanical losses. Also, such propulsion systems effectively employ a pushing action for rotating the propeller drive of the water craft, which are inefficient and noisy in operation. The rotation speed of the propeller is also limited by the mechanical ratio between the sprocket and the rotational movement of the conversion wheels and the engagement between the chain and the sprocket or the gear assembly. Furthermore, such systems require high maintenance in sustaining their operation.
It is a principal object of the present invention to provide a pedal propulsion system which is conveniently adaptable in a transportation conveyance.
It is another object of the present invention to provide a pedal propulsion system which is efficient and low noise in operation.
It is another object of the present invention to provide a pedal propulsion system which is relatively simple in construction and yet provides efficient high speed operation of a water craft.
It is another object of the present invention to provide a pedal propulsion system which is simple to maintain and easy for the replacement of parts.
It is still an object of the present invention to provide a pedal propulsion system operative for steering a water craft without the need of a rudder.
It is yet another object of the present invention to provide a pedal propulsion system which is portable so that it can be conveniently and removably adapted within a water craft such that it may be conveniently removed from the water craft to facilitate transport of the water craft and the propulsion system separately from one another.
Other objects and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments thereof in connection with the accompanying drawings in which
With reference to the drawings in which like reference numerals designate corresponding parts in the different views, the pedal propulsion system 10 of the present invention has a supporting frame 11 with a seat 12 slidably mounted on the supporting frame 11 and the seat position is adjustable to accommodate an operator sitting therein to operate the propulsion pedals 13 and 14 comfortably. The supporting frame 11 is preferably of a portable construction which has supporting legs 15, 16 and 17 such that it may be conveniently and removably adapted within a water craft such as a canoe 18. A canoe 18 is shown as an exemplary embodiment of the application of the propulsion system of the present invention. It will be understood by those skilled in the art that the system may be applicable for powering other transportation conveyances such as a boat and the like. The pedal propulsion system has a pedal assembly which includes a drive wheel 19 mounted on a crank shaft 20. The pedals 13 and 14 are mounted at the two ends of the crank shaft 20 which is rotatably mounted on an extension bifurcated arm 21 extending horizontally outward from a vertical post 22 of the supporting frame 11. The rotational axis of the drive wheel 19 extends generally perpendicular to the longitudinal axis of the canoe 18. A drive belt 23 engages with the drive wheel 19 and in a partially twisted manner also engages with a transfer wheel 24 having its rotational axis oriented at an angle of up to 90 degrees with respect to the rotational axis of the drive wheel 19. The drive wheel 19 has a larger diameter than the diameter of the transfer wheel 24 so as to enhance the ease in rotating the transfer wheel 24 by the drive wheel 19. The transfer wheel 24 is mounted at a front end of an elongated rotary shaft 25. The rotary shaft 25 is rotatably located within a protective outer tube 26 which extends through an access opening 27 formed at the lower portion of the vertical post 22 of the supporting frame 11. The outer tube 26 with the rotary shaft 25 rotatably located therein extends rearwardly towards the rear of the canoe. Thus, operation of the pedals 13 and 14 to rotate the drive wheel 19 will cause the transfer wheel 24 to rotate, in turn, the rotary shaft 25.
Preferably, a first sprocket is employed as the drive wheel 19 and a second sprocket is used as the transfer wheel 24. Both the drive wheel 20 and the transfer wheel 24 have transverse grooves 28 and 29 respectively, having the same configuration and pitch, formed on their circumferential drive surfaces. A sequential or synchronous drive belt with a toothed drive surface having transverse teeth 30 is looped and coupled between these sprockets so as to provide an efficient and low noise operation of the rotation of both of these sprockets. The transverse teeth 30 of the synchronous drive belt 23 have mating configuration and pitch as those of the transverse grooves 28 and 29 formed on the first sprocket namely the drive wheel 19 and the second sprocket namely the transfer wheel 24.
A belt guard 31 is located at a short distance and spaced above the access opening 27 of the vertical post 22 and the transfer wheel 24. The belt guard 31 extends generally horizontally in a cantilever manner from the vertical post 22 of the supporting frame 11, and it has a through opening 32 formed therein. The drive belt 23 passes through the through opening 32 such that the belt guard 31 serves to ensure the proper and snug engagement of the drive belt 23 with the drive wheel 19 and the transfer wheel 24. The transfer wheel 24 is rotatably mounted on a vertical plate 33 having a top end portion attached to the outer edge of the belt guard 31. The belt guard 31 and the vertical plate 33 may be integrally formed by an inverted sideway L-shaped bracket provided on the vertical post 22 as best shown in
The front end of the protective tube 26 may be fixedly mounted to the access opening 27. The rotary rod 25 is also preferably slidable slightly in a back and forth manner relative to the protective tube 26 so as to allow for a slight back and forth movement of the transfer wheel 24 during operation. A multi-sided coupling hole 34 is formed at the rear end of the rotary shaft 25. An elongated flexible transmission cable 35 having an elongated flexible steel cable 36 rotatably located within a flexible outer jacket 37 is connected to the rear end of the protective tube 26. The steel cable 36 has a multi-sided cross sectional shape and dimensioned end portion 38 equal to the multi-sided coupling hole 34 formed at the rear end of the rotary shaft 25 such that the end of the steel cable 36 is insertable into the multi-sided coupling opening 34 of the rotary shaft 25 to engage with the latter. For simplicity of illustration, a square shaped coupling opening 34 is shown at the end of the rotary shaft 25 and a cross sectional square shaped end portion is shown in the flexible transmission cable 35 in the exemplary embodiment. The transmission cable 35 and the protective tube 26 of the rotary shaft 25 are mounted together with a tubular threaded coupling sleeve 39 removably mounted to threaded end portions formed in the inside surface of the rear end portion of the protective tube 26 and the end portion of the outer jacket 37 of the transmission cable 35 so as to facilitate easy connection and disconnection between the transmission cable 35 and the outer tube 26 of the rotary shaft 25 for easy maintenance and replacement of parts. The rotation of the rotary shaft 25 causes the steel cable 35 to rotate accordingly within the outer jacket 37.
The propeller drive assembly 40 has an upper drive unit 41 and a lower drive unit 42 mounted at the top end and lower end respectively of a vertical support rod 43. An upper sprocket 44 is rotatably mounted to a rotary shaft 45 which is rotatably mounted in the upper drive unit 41. The front end 46 of the rotary shaft 45 is exposed in a threaded opening 47 in the upper drive unit 41. A multi-sided or square coupling hole 48 is formed at the front end portion of the rotary shaft 45 such that the multi-sided or square rear end portion 49 of the flexible steel cable 25 may be inserted therein to couple the steel cable 25 to the rotary shaft 45 of the upper drive unit 41. A threaded coupling sleeve 50 having threaded ends is provided for removably securing to the end of the outer jacket 26 of the flexible cable 25 and to the threaded opening 47 of the upper drive unit 41. A propeller rotary drive shaft 51 is rotatably mounted in the lower drive unit 42 of the propeller drive assembly 40. A lower sprocket 52 is mounted on the propeller rotary drive shaft 51 and the propeller 53 is mounted on the rear end portion of the propeller rotary drive shaft 51 extending rearwards from the lower drive unit 42. The upper sprocket 44 has a larger diameter than the lower sprocket 52 to provide efficient rotation of the lower sprocket 52 by the upper sprocket 44. A propeller drive belt 54 is coupled between the upper sprocket 44 and the lower sprocket 52 by looping between the upper sprocket 44 and lower sprocket 52. The upper sprocket 44 and the lower sprocket 52 preferably have transverse grooves of similar configuration and dimensions formed on their circumferential surfaces; and the propeller drive belt 54 preferably is a synchronous drive belt having transverse teeth formed on its drive surface with the transverse teeth having complementary mating configuration and dimensions of those of the transverse grooves formed on the circumferential surfaces of the upper sprocket 44 and the lower sprocket 52.
An inverted sideway L-shaped mounting rod 55 is rotatably mounted to the vertical support rod 43 with at least one and preferably two mounting rings 56 and 57 extending in a cantilever manner on a vertical arm portion 58 of the mounting rod 55 such that the propeller drive assembly 40 is rotatable relative to the mounting rod 55. A plurality of transverse through openings 59 spaced from one another are formed on a horizontal arm portion 60 of the mounting rod 55. The horizontal arm portion 60 of the mounting rod 55 is slidably insertable into a mounting bracket 61 secured on the deck 62 located at the rear end portion of the canoe 18 for removably mounting the propeller drive assembly 40 to the canoe 18. A plurality of spaced openings 63 are formed on the side walls of the mounting bracket 61 such that the horizontal position of the propeller drive assembly 40 relative to the canoe 18 may be selectively adjustable by inserting a securing pin 64 through a selected opening 63 aligned with a selected through opening 59 of the horizontal arm portion 60. The securing pin 64 may be securely retained in place with a cotter pin 65.
A pintle 66 is provided on a side arm 67 extending sideways from the upper drive unit 41. An elongated steering rod 68 having an eyelet 69 formed at its rear end with the eyelet 69 slidably engaged with the pintle 66. Thus, the propeller drive assembly 40 may be pivoted relative to the canoe 18 by pulling or pushing the steering rod 68 for steering the canoe when the pedal propulsion system is in operation. The steering rod 68 is mounted to the side of the canoe with a removable retaining clamp 70 to facilitate the removal of the pedal propulsion system from the canoe. A vertical handle 71 is provided at the front end of the steering rod 68 for easy and convenient operation of the steering rod 68 in steering the canoe by the operator sitting on the pedal propulsion system of the present invention.
The synchronous belt drive system of the present invention provide an efficient and low noise system for driving a transportation conveyance in a fast speed with ease; and the canoe can be steered without employing a rudder. The system also may be provided in a portable manner in the water craft such that it may be conveniently removed from the latter for easy transport of the water craft and the propulsion system separate from one another.
While the preferred embodiments of the invention have been described above. It will be recognized and understood that various modifications may be made therein and the appended claims are intended to cover all such modifications which may fall within the scope of the present invention. For example, the propeller drive assembly may be mounted on the transom board of a relatively light weight boat with clamps for driving the boat.
