Patent Publication Number: US-2015076787-A1

Title: Recumbent human powered vehicle with a reciprocating linear drive

Description:
BACKGROUND OF THE INVENTION  
     1. Field of the Invention 
     This invention is generally related to recumbent human-powered vehicles such as bicycles, tricycles and other multi-wheel variants that are propelled by a reciprocating thrust motion of the operator using a linear drive mechanism connected by a flexible power link to a double overrunning clutch transmission with returning springs. The human-powered vehicle is propelled with the use of pedals which are positioned approximately above and on either side of the front wheel to create a short wheel base in the human-powered vehicle, with the seat located between the front and rear wheels. The human-powered vehicle may be propelled with the thrust motion of one leg, both legs in an alternating motion such as a typical crank-shaft bicycle, or with the use of both legs simultaneously. 
     2. Description of the Prior Art 
     Recumbent human-powered vehicles such as bicycles and tricycles and human-powered vehicles with linear drivers are known in the prior art. Some examples of such art are found in U.S. Pat. Nos. 4,878,684; 5,979,922; 5,732,963; 5,290,054; 5,915,710; 7,048,290 B2; and WO 2006/002577. Indeed, various bicycle systems and rider positions have been proposed in the art in an effort to provide a rider position that is both comfortable and utilitarian. For example, rectilinear pedal drive systems having two drive chains and an upright rider position are known in the art. Such a system has a separate, vertically-oriented structure mounted to a bicycle frame for supporting and guiding the pedals when in an upright riding position. Recumbent human-powered vehicles with pivotally mounted pedals movable along an arcuate motion have been proposed. Other prior pedal drive systems use interconnected pedals that allow only alternating pedal motion, while other systems allow for both pedals to move forward and rearward together. For reasons provided below, these examples of human-powered vehicles are deficient when compared to the present invention. 
     U.S. Pat. No. 4,878,684 (“the &#39;684 patent”) discloses a recumbent bicycle with a crank transmission, which has certain disadvantages when compared to the present invention, including, for example, lower efficiency, crank kick-backs and crank getting stuck. The recumbent bicycle of the &#39;684 patent has the pedals in front of the seat, with both the seat and pedals being positioned along the frame of the bicycle between the rear and front wheels. Due to this positioning, the &#39;684 patent bicycle has a wheel base that is substantially longer than one of a conventional upright bicycle. The increased length and resultant weight make such a bicycle difficult to maneuver and slower than either conventional bicycles or the human-powered vehicle disclosed in the present invention. A shorter wheel base and lighter human-powered vehicles are desirable. In addition, as explained below, the crank transmission of the &#39;684 patent provides only 24% or less muscle efficiency. Such inefficiency is too low, especially for a larger, heavier vehicle described in the &#39;684 patent. To overcome the disadvantages of crank-operated recumbent bicycles such as those described in the &#39;684 patent, it is desirable to utilize linearly reciprocating pedals positioned in front of the front wheel of the human-powered vehicle, as shown further below. 
     U.S. Pat. No. 5,979,922 (“the &#39;922 patent”) describes a recumbent bicycle with a linear drive mechanism and a partially linearly reciprocating pedal motion; however, when compared to the present invention, the bicycle of the &#39;922 patent has many disadvantages. First, due to the length of the pedal sliders described in the &#39;922 patent, the wheel base of the resulting bicycle is substantially longer than of a conventional bicycle. Thus, similar to the &#39;684 patent, the bicycle of the &#39;922 patent is both long and heavy and suffers from the same disadvantages as the &#39;684 patent bicycle. Moreover, the design described in the &#39;922 patent has a potential problem with stability and requires retractable stabilizer wheels, which make this design dangerous and impractical for most riders. Indeed, the aforementioned disadvantages are typical of most recumbent bicycles known in the art. The presently described invention addresses this known problem with a wheel base equal to or only slightly longer than a conventional upright bicycle. Such a design, coupled with the novel drive mechanism proposed herein, eliminates the problems associated with a long wheel base. Second, the recumbent bicycle of the &#39;922 patent does not allow for independent pedal motion wherein the rider chooses simultaneous or alternating pedal motion, which may be powered by a rider having only one leg. Finally, the &#39;922 patent lacks in power efficiency provided with the use of the novel linear drive mechanism connected by a flexible power link to a double overrunning clutch transmission with returning springs. 
     Additional prior art references accumulate many of the problems described above. These include U.S. Pat. Nos. 5,732,963; 5,290,054; 5,915,710; and 7,048,290. 
     Therefore, a need in the art exists for an efficient recumbent human-powered vehicle with a wheel base approximately that of a conventional upright bicycle, low weight and convenient seating and steering, and that may be operated with a simultaneous thrust motion of both legs, alternative thrusts of either leg, or with one leg only. A further need in the art exists for a human-powered vehicle as an alternative to automobiles and other form of transit. The present invention fulfills these and other needs by providing a short wheel base recumbent human-powered vehicle propelled by a reciprocating thrust motion of the operator using a linear drive mechanism connected by a flexible power link to a double overrunning clutch transmission with returning springs. 
     SUMMARY OF THE INVENTION  
     Accordingly, it is an object of the present invention to provide a recumbent human-powered vehicle propelled by a reciprocating thrust motion of the operator using a linear drive mechanism connected by flexible power links to a double overrunning clutch transmission with returning springs. The human-powered vehicle is propelled with the use of pedals, which are positioned approximately above and on either side of the front wheel to create a short wheel base, approximately the same or slightly larger than that of a conventional upright bicycle, with the seat located between the front and rear wheels. The human-powered vehicle generally comprises a frame supporting a rider in a substantially recumbent position, a driven wheel rotatably mounted on the frame, a drive gear for driving the driven wheel, left and right pedals mounted on the front of the frame in front of the steering column, with the right and left pedals reciprocally traveling in a substantially horizontal rectilinear path. The top extremities of a pair of pedal sliders are positioned for independent pendulum-type oscillation in a pedal-slider bracket, which is connected to a frame through a front bracket. The linearly reciprocating pedals are attached to the lower extremity of the pedals sliders and are rotationally linked to the linear drive mechanism through a pair of flexible power links such as chains or flexible cords so as to transfer power from the pedals to the diver mechanism. The linear drive mechanism is located between the wheels, and the recumbent seat is located on the beam in front of or between the rear wheel(s) and the steering column. The drive mechanism is connected to the vehicle main chain axis drive/transmission, which is connected to the frame and includes a pair of sprocket wheels connected a pair of overrunning clutches allowing transmission of the moving force to the main chain axis and returning back as overrunning clutches in idle mode. To return the flexible power links and pedals back to a working position, the flexible power links are connected to a pair of linear springs, which are connected to the vehicle frame. Alternatively, the flexible power links may be returned to original or working position by spiral torsion springs, which are also connected to the flexible power links and the vehicle frame. The pedals execute a back-and-forth motion between a fully extended and a contracted position. Unlike other recumbent human-powered vehicles, the present invention does not utilize a crank transmission and may be propelled with the thrust motion of one leg, both legs in an alternating motion such as a typical bicycle using a crank mechanism, or with the use of both legs simultaneously. 
     The human-powered vehicle of the present invention has a very efficient power transfer to the wheels, thereby increasing the speed of the vehicle as compared to typical recumbent bicycles and tricycles, permitting a greater speed and distance of travel, and allowing to carry additional weight, such as, for example, extra passengers. Typical crank-operated human-powered vehicles such as bicycles and tricycles are capable of only 24% muscle efficiency (see, e.g., Efficiency Measurements of Bicycle Transmissions—A Neverending Story, Bernhard Rohloff and Peter Greb, Human Power, 55, 11-15 at 13—attached as addendum A, expressly incorporated herein by reference) as compared to the novel linear drive and double-overrunning clutch transmission utilized in the present invention, which use approximately 90% or higher muscle efficiency. The increased efficiency, relatively lighter weight, comfort and ease of steering of the human-powered vehicle described herein, make it as an alternative to fuel-consuming vehicles for local travel and transport of lighter weight loads. 
     A particular feature of the recumbent position and frame of the vehicle described herein is a riding position that, compared with the upright seated position, affords more efficient and comfortable propulsion, where muscle stress may be more readily alternated among muscles groups of both the front and back of the body. The recumbent position of the seat in the present invention offers additional medical benefits that are well-known and described in the art of recumbent cycling, such as, for example, decreased pressure on the groin area. 
     Due to the relatively short wheel base of the present invention and its unique linear drive transmission, the human-powered vehicle of the present invention is generally capable of attaining speeds substantially higher than those of conventional crankshaft-operated recumbent bicycles and tricycles. The combination of the design with a short wheel base and the linear drive mechanism described herein also permits the user of the vehicle to propel heavier loads, such as additional passengers, groceries, and other weight. 
     Further objects and advantages of this invention will become apparent from a consideration of the included figures with corresponding description. 
    
    
     
       DESCRIPTION OF THE DRAWINGS  
         FIG. 1  is a perspective view of an embodiment of the present invention. 
         FIG. 2A  is a perspective view of the linear drive mechanism and a particular embodiment of the flexible power link—a vinyl-coated metal cord—used in the present invention. 
         FIG. 2B  is a perspective view of the linear drive mechanism and a particular embodiment of the flexible power link—a metal chain—used in the present invention. 
         FIG. 3A  is a cross-sectional view of a particular embodiment of the transmission of the present invention (utilizing drums and cord as a flexible power link). 
         FIG. 3B  is a side view of a particular embodiment of the transmission and linear drive mechanism of the present invention (utilizing drums and cord as a flexible power link). 
         FIG. 4A  is a cross-sectional view of a particular embodiment of the transmission of the present invention (utilizing sprocket wheels and chain as a flexible power link). 
         FIG. 4B  is a side view of a particular embodiment of the transmission and linear drive mechanism of the present invention (utilizing sprocket wheels and chain as a flexible power link). 
       
         
           
             
                 
               
                 
                   TABLE 1 
                 
               
              
                 
                     
                 
                 
                   Figures Reference 
                 
              
             
             
                 
                 
              
                 
                   Number Reference  
                     
                 
                 
                   In Figures 
                   Part 
                 
                 
                     
                 
                 
                    1 
                   Linear drive recumbent  
                 
                 
                     
                   human-powered vehicle 
                 
                 
                    2 
                   Frame 
                 
                 
                    3 
                   Rear wheel 
                 
                 
                    4 
                   Top tube 
                 
                 
                    5 
                   Low tube 
                 
                 
                    6 
                   Steering column 
                 
                 
                    7 
                   Pedal slider bracket 
                 
                 
                    8 
                   Right pedal slider 
                 
                 
                    9 
                   Left pedal slider 
                 
                 
                   10 
                   Right power link 
                 
                 
                   11 
                   Left power link 
                 
                 
                   12 
                   Front wheel 
                 
                 
                   13 
                   Transmission/main chain axis  
                 
                 
                     
                   drive 
                 
                 
                   14 
                   Main drive sprocket wheel 
                 
                 
                   15 
                   Main drive chain 
                 
                 
                   16 
                   Rear wheel drive sprocket wheel 
                 
                 
                   17 
                   Adjustable handlebar 
                 
                 
                   18 
                   Seat 
                 
                 
                   19 
                   Linear drive mechanism 
                 
                 
                   20 
                   Flexible power link  
                 
                 
                     
                   (vinyl-coated metal cord) 
                 
                 
                   21 
                   Flexible power link (metal chain) 
                 
                 
                   22 
                   Front fork 
                 
                 
                   23 
                   Pedal slider bracket holder 
                 
                 
                   24 
                   Transmission bracket 
                 
                 
                   25 
                   Seat support rod 
                 
                 
                   26 
                   Transmission axle 
                 
                 
                   27 
                   Overrunning clutch outer ring 
                 
                 
                   28 
                   Overrunning clutch inner ring 
                 
                 
                   29 
                   Linear returning spring 
                 
                 
                   30 
                   Spiral torsion returning spring 
                 
                 
                   31 
                   Bearing 
                 
                 
                   32 a, b 
                   Sprocket 
                 
                 
                   33 a, b 
                   Drum 
                 
                 
                   34 
                   Power stroke cycle 
                 
                 
                   35 
                   Return stroke cycle 
                 
                 
                   36 
                   Human power/muscle force 
                 
                 
                   37 
                   Pedals 
                 
                 
                     
                 
              
             
           
         
       
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     Referring to  FIGS. 1-3 , in one embodiment of the present invention, a recumbent bicycle  1  has a double-stroke linear drive mechanism  19  integral with a bicycle frame  2 . The recumbent bicycle  1  has many of the standard components found in typical bicycles, such as a rear wheel  3 , top tube  4 , low tube  5 , steering column  6 , front wheel  12 , main drive sprocket  14 , main drive chain  15 , rear wheel drive sprocket  16 , adjustable handlebar  17 , front fork  22 . 
     Bicycle  1  is provided with a right pedal slider  8  and left pedal slider  9 , with the upper ends of the pedal sliders  8  and  9  joined in a pedal slider bracket  7  of a pedal slider bracket holder  24  of frame  2  to create a pendulum-type oscillation movement. Pedals  37  are attached to the lower ends of each of the pedal sliders  8  and  9 . 
     Bicycle  1  is provided with a drive mechanism  13 , which is positioned for rotation in a transmission bracket  24  of frame  2 . A right power link  10  and a left power link  11  are each attached to the lower ends of pedal sliders  8  and  9 . 
     Seat  18  of the recumbent bicycle  1  is adjustably attached to frame  2  to tube  4  and has adjustable seat support rod  25 . Although in a preferred embodiment of the present invention, seat  18  is substantially recumbent, this position need not be completely horizontal in relation to tube  4 , the pedals  37  and drive mechanism  13 . A rider position below or above the horizontal plane defined by the drive mechanism may also work with the human-powered vehicle of the present invention. In certain embodiments, it may be beneficial to raise the seat  18  above the plane defined by the drive mechanism  13  for better visibility of the vehicle operator. 
     Referring to  FIGS. 3A and 3B , drive mechanism  13  has a double stroke linear drive mechanism  19  and flexible power links  10  and  11 . The flexible power links  10  and  11  may be made of any flexible material such as, for example, vinyl-coated metal cord  20  ( FIGS. 2A ,  3 A,  3 B) or metal chain ( FIGS. 2B ,  4 A,  4 B). While the present invention provides two specific examples of flexible power links—vinyl-coated metal cords and metal chains—useable with the linear drive mechanism described herein, the flexible power links may also be made out of any number of materials suitable to the typical stresses experienced with the use of the linear drive mechanism of the present invention. Flexible power links  10  and  11  are each partially wrapped around a one-way drum  33   a  and  33   b  similar to one-way sprocket wheels  16  that are normally found on the rear axle of bicycles. 
     The overrunning clutches  27  and  28  are installed on transmission axle  26 , allowing drums  33   a  and  33   b  to freely rotate when no pedaling occurs. Overrunning clutches  27  and  28  engage the transmission when pedaling occurs to induce rotation of the main drive sprocket wheel  14 , which is rigidly connected to transmission axle  26 . The main drive sprocket wheel  14  acts like a standard forward sprocket wheel on a standard bicycle. The transmission axle  26  is located in a transmission bracket  24  and has bearings  31 . To return drums  33   a  and  33   b  in a working position, flexible power link  20  performs idle motion on a return stroke cycle  35 , as spiral torsion return spring  30  rotates the overrunning clutch outer ring  27  (loosely connected to drum  33   a  and  33   b ) in the opposite direction. Then the outer ring  27  performs a power stroke cycle  34  when drum  33   a  and  33   b  rotates the overrunning clutch outer ring  27  engaged with inner ring  28  and transmit the rotation to transmission axle  26 , the main drive sprocket wheel  14  and the main drive chain  15 . At the same time, the overrunning clutch inner ring  28  compresses a spiral torsion returning spring  30 . 
     The left and right power stroke cycles  34  and  35  are independent from one another. Because of this independent action, the rider can use both legs simultaneously when necessary to provide more power to the vehicle, such as, for example, when accelerating, riding uphill or carrying larger loads (e.g., passengers in a rickshaw-like configuration). Likewise, the rider may alternate between left and right leg motion such as used in a typical upright or recumbent bicycle. Finally, the vehicle of this invention may be propelled with the use of either the right or left leg in a single-stroke action. 
     Referring to  FIGS. 4A and 4B , the right power link  10  and left power link  11  may be steel chains  21  that transmit power through a power stroke  34  to sprockets  32   a  and  32   b  and rotate these sprockets by engaging the overrunning clutches  27  and  28  to induce rotation of transmission axle  26  and main drive sprocket wheel  14 , which is rigidly connected to transmission axle  26  located in a transmission bracket  24  with bearings  31 . To return sprockets  32   a  and  32   b  to a working position, metal chain  21  performs idle motion on a return stroke cycle  35  as a linear returning spring  29  rotates the overrunning clutch outer ring  27  (loosely connected with sprocket  32   a  and  32   b ) in the opposite direction. Then the outer ring  27  performs power stroke cycle  34  when sprocket  32   a  and  32   b  rotates the overrunning clutch outer ring  27  engaged with inner ring  28  and transmit the rotation to transmission axle  26 , the main drive sprocket wheel  14  and the main drive chain  15 . At the same time, the chain  15  extends the linear returning spring  29 . 
     The torsion and linear springs used in this invention may be made of any suitable material allowing for a spring-like action, such as, for example, metal, rubber or plastic. Likewise, the vehicle of the present invention may be constructed out of typical materials used for bicycles, tricycles and other human-powered vehicles, including metal, plastic, rubber, fiberglass, and wood and wood composite materials. 
     Although certain figures shown herein describe a bicycle (e.g.,  FIG. 1 ), the linear drive mechanism connected by a flexible power link to a double overrunning clutch transmission with returning springs may be utilized on various recumbent human-powered vehicles such as tricycles, four-wheeled vehicles for carrying larger loads and passengers and other multi-wheel variants.