Abstract:
The bicycle pedaling system includes a weighted outer disc having a bicycle chain sprocket(s) mounted on one side, the outer disc having a central bore with a plurality of ratchet teeth projecting inwardly at an angle from the interior surface of the central bore. An inner disc is coaxially mounted in the central bore, the inner disc being journaled to bicycle pedals, the inner disc having at least one pawl projecting from its periphery to selectively engage the ratchet teeth. When pedaling, the pawl engages the ratchet teeth and propels the bicycle, and when pedaling is stopped, the outer disc freely rotates about the inner disc to thereby provide continuous momentum to ease subsequent resumption of pedaling effort.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/202,938, filed Apr. 21, 2009. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to bicycle chain drives, and more particularly to a bicycle pedaling system that reduces the pedaling effort required for traversing slopes. 
       DESCRIPTION OF THE RELATED ART 
       [0003]    The advent of bicycles has increased personal mobility around the world. The activity provides great health benefits and a positive environmental impact from bicycling commuters since no harmful polluting gases are produced from the activity. While bicycles provide many positive benefits, at times, it still requires great physical effort in traversing certain terrains such as slopes. 
         [0004]    Current bicycles include a multi-sprocket gearing system that allows a user to select a relatively ideal gear for traversing a given terrain depending on how much physical effort the user is willing to put forth. However, this type of system does not fully maximize the physical energy provided by the user. Another type of bicycle crank system utilizes a relatively complex array of chains and sprockets for a flywheel design, which adds considerable weight to the bicycle and may be a daunting prospect for some users. Thus, it would be beneficial in the art to provide a bicycle crank system that reduces pedaling effort required to traverse difficult terrain. 
         [0005]    Thus, a bicycle pedaling system solving the aforementioned problems is desired. 
       SUMMARY OF THE INVENTION 
       [0006]    The bicycle pedaling system includes a drive sprocket wheel that has a weighted outer disc having at least one bicycle chain sprocket mounted on one side, the outer disc having a stepped central bore with a plurality of ratchet teeth projecting inwardly at an angle from the interior surface of the central bore. The stepped portion of the central bore defines at least one race for ball bearings. A stepped inner disc is coaxially mounted in the central bore, the inner disc being journaled to bicycle pedals. The inner disc has a first outer diameter and surface and a second outer diameter and surface, the second outer diameter of the inner disc being larger than the first outer diameter of the inner disc. At least one pawl projects outwardly at an angle from the first outer surface of the inner disc. The pawl is one-way engageable with the ratchet teeth of the outer disc so that when pedaling, the pawl arm engages the ratchet teeth and propels the bicycle, and when pedaling is stopped, the outer disc freely rotates about the inner disc to thereby provide continuous momentum to ease subsequent resumption of pedaling effort. 
         [0007]    These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of a bicycle pedaling system according to the present invention. 
           [0009]      FIG. 2  is an exploded perspective view of the bicycle pedaling system of  FIG. 1 . 
           [0010]      FIG. 3  is a side view of the bicycle pedaling system of  FIG. 1 , showing the chain sprocket mounting side of the sprocket drive wheel. 
           [0011]      FIG. 4  is a side view of the bicycle pedaling system of  FIG. 3 , showing the opposite side of the sprocket drive wheel from  FIG. 3 . 
           [0012]      FIG. 5  is a section view of a bicycle chain drive wheel, showing details of the bicycle pedaling system of  FIGS. 1-4 . 
           [0013]      FIG. 6  is an environmental side view of a bicycle pedaling system according to the present invention, shown with an optional momentum booster on the rear wheel of the bicycle. 
           [0014]      FIG. 7  is a side view of the momentum booster of  FIG. 6 , showing the wheel from the opposite side as  FIG. 6  and without the tire, and showing optional weights attached to the momentum booster. 
           [0015]      FIG. 8  is a section view of the wheel assembly of  FIG. 6 , showing details of the momentum booster. 
           [0016]      FIG. 9  is an environmental side view of a bicycle pedaling system according to the present invention, shown with an alternative embodiment of the momentum booster on the rear wheel of the bicycle. 
       
    
    
       [0017]    Similar reference characters denote corresponding features consistently throughout the attached drawings. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    The present invention relates to a bicycle pedaling system that maximizes generated momentum to ease traversal of slopes or other physically demanding terrain. Bicycle chain drives include a sprocket drive wheel mounted to the bicycle frame, the drive wheel having pedals to crank the drive wheel, the chain drive having a rear driven sprocket wheel coupled to the rear wheel of the bicycle. Referring to  FIGS. 1 ,  2  and  5 , the bicycle pedaling system  10  includes a sprocket drive wheel that has a weighted circular outer disc  20  and a circular inner disc  40  coaxially mounted within the outer disc  20 . The outer disc  20  includes first and second sides A, B and a stepped central bore  21  (a bore having a series of shoulders defining ledges of progressively smaller diameter), through which the inner disc  20  and the pedals P may be mounted. 
         [0019]    The first side A of the outer disc  20  includes an axially projecting, externally stepped axle  22 . The stepped portions of the axle  22  define mounting seats or shoulders for one or more bicycle chain sprockets  12 ,  13 ,  14  that are attached to the outer disc  20  by fasteners  26 . Each sprocket  12 ,  13 ,  14  has a different diameter, and each stepped portion of the axle  22  accommodates a corresponding diameter sprocket. The sprockets  12 ,  13 ,  14  receive a chain that also extends over the rear or driven sprocket(s) on a bicycle B. 
         [0020]    A first cap  24  having a central bore  25  covers the distal end of the axle  22 . The first cap  24  may be secured to the axle  22  by fasteners  26 . The other or second side B of the outer disc  20  also includes a second cap  28  that covers the second side B when all the parts are assembled. 
         [0021]    The inner disc  40  is substantially T-shaped in cross section and includes a circular flanged portion  41  radially projecting from one axial end of the smaller diameter main body portion  46  of the inner disc  40 . Thus, the outer edge of the circular flanged portion  41  has a first diameter, and the main body  46  has a second diameter, the first diameter being larger than the second diameter. The outer surface of the flanged portion  41 , together with an inner, annular groove  23  within the bore  21  of the outer disc  20 , defines a race for ball bearings  45 . The opposite axial end of the main body portion  46  includes an annular groove  42 , which, together with an inner surface  27  of the second cap  28 , defines a second race for another set of ball bearings  44 . The sets of ball bearings  44 ,  45  allow smooth rotation of the outer and inner discs  20 ,  40  relative to each other. Pedals P have a square spindle and are operatively mounted to the inner disc  40  through a journal j journal or adapter that may be keyed to the bore  25  in the first cap  24 , and then through the bores in the inner disc  40  and the second cap  28 . 
         [0022]    The bicycle pedaling system  10  facilitates decreased physical effort to traverse adverse terrain, e.g., slopes, by maximizing user-generated momentum from pedaling. To that end, the bicycle pedaling system  10  includes features that selectively drive the outer disc  20  when pedaling, but permit the outer disc  20  to freely rotate when pedaling is stopped. Due to the weight of the outer disc  20 , the rotation of the outer disc  20  produces additional rotational momentum from inertia or a flywheel effect that continues even with the pedals P are not being used to crank the drive sprocket so that subsequent pedaling will not require as much torque or effort to overcome the terrain obstacle. 
         [0023]    To selectively drive the outer disc  20 , reference is made to  FIG. 4 . The bicycle pedaling system  10  includes a ratchet system between the two discs  20 ,  40 . The outer disc  20  includes a plurality of integrally formed ratchet teeth  29  radially inward in the outer disc  21 . The ratchet teeth  29  project inwardly, at an angle towards the center of the bore  21 , and each tooth  29  includes a front catch surface  31  and a rear, non-catch, sloping surface  30 . The inner disc  40  includes at least one axially extending notch, recess or pocket  48  formed intermediate the two axial ends of the inner disc  40 . The pocket  48  seats a pivotally mounted pawl  46  that extends at an angle counter to the angular orientation of the ratchet teeth  29 . The pawl  46  is normally biased in the above position by a spring  47 . Thus, whenever the inner disc  40  is rotated in the direction indicated by arrow  11  by user input on the pedals P, the pawl  46  engages the front surface  31  of one of the ratchet teeth  29  to drive the outer disc  20 . When pedaling is stopped, the outer disc  40  continues to rotate due to inertia, the ratchet pawl  46  being pivoted downward by the rear surface  30  of successive teeth  29 . 
         [0024]    In some instances, momentum generated from the outer disc  20  may not be sustainable or sufficient to overcome some of the terrestrial irregularities or undulations in the path of travel. To help maintain the generated momentum, the bicycle pedaling system  10  optionally includes a momentum booster  50  forming the rear wheel of a bicycle B. 
         [0025]    As shown in  FIG. 6-8 , the momentum booster  50  includes a relatively thin, circular wheel disc  52  and an annular weighted rim  54  mounted to the wheel disc  52 . The wheel disc  52  is attached to the rear hub  56  of the bicycle by an intermediate annular ring, mounting bracket or mounting flange  58 . The annular mounting flange  58  may be welded or formed on the hub  56  and includes a plurality of angularly spaced mounting holes through which fasteners  59  may be used to mount the hub  56  to the wheel disc  52  via corresponding mounting holes  57 . The wheel disc  52  is preferably solid to support the additional weight of, and stresses from, the weighted rim  54 , but optional holes  53  may be formed thereon to reduce the overall weight of the wheel disc  52 . The holes  53  should be equidistantly spaced about the central axis of the wheel disc  52  to maintain overall balance of the rear wheel. 
         [0026]    The annular weighted rim  54  is relatively thicker and has more mass than the wheel disc  52  in order to concentrate additional weight near the outer edge of the rear bicycle wheel and thereby maximize the momentum thereof for any given force acting on the rear bicycle wheel. Thus, a majority of the weight of the rear bicycle preferably rests in the weighted rim  54 . Density of a given material has an effect on the weight of the annular weighted rim  54 , so the dimensions of the rim  54  can be changed according to the desires of the user as long as the momentum boosting effect can be maintained, e.g., with a given desired momentum boosting effect, the width and length of the rim  54  can be relatively small if high density material is used or larger for a relatively lower density material. The weighted rim  54  helps to boost and maintain momentum in a similar manner as the outer disc  20 . Due to the weight of the weighted rim  54 , the rotation of rim  54 , in response to pedaling, produces additional rotational momentum from inertia or a flywheel effect. This, in combination with the rotational momentum from the outer disc  20 , ensures that momentum can be sustained for a longer period of time than by the outer disc  20  alone. 
         [0027]    To mount the annular weighted rim  54 , the rim  54  includes an inner stepped ledge  64  with an inwardly projecting extension or flange  62 . The rim  54  also includes a drop well  60  on the outer, circumferential edge for mounting a bicycle tire T thereon. During assembly, the ledge  64  rests on the outer, circumferential edge of the wheel disc  52  while the projecting flange  62  rests on one side of the wheel disc  52 . The projecting flange  62  includes a plurality of angularly spaced mounting holes where fasteners  66  may be used to securely mount the weighted rim  54  to the wheel disc  52 . When assembled, the ledge  64  extends past the plane on the opposite side of the wheel disc  52  in order to distribute the weight and help balance the overall rear bicycle wheel. 
         [0028]    If additional weight is required or desired, the wheel disc  52  includes a plurality of mounting holes  70  where additional weights  68  may be mounted. The mounting. holes  70  should be equidistantly spaced about the central axis of the rear bicycle wheel for balancing, and the holes  70  may be single holes, pairs or any other number as long as the additional weights  68  can be secured onto the wheel disc  52 . Each additional weight  68  may be an annular or arcuate segment block of material with mounting holes corresponding to the holes  70 . When assembled, the additional weights  68  are mounted to the wheel disc  52  on the side opposite the flange  62  with fasteners  69 . In this manner, balance can be maintained. In addition, the arcuate, outer edge of the additional weight  68  abuts the extending portion of the ledge  64  so that the ledge  64  may be used as an installation guide for mounting the additional weight  68 . 
         [0029]    An alternative embodiment of a momentum booster  80  is shown in  FIG. 9 . In this embodiment, the alternative momentum booster  80  is configured for detachable mounting to the rear bicycle wheel, i.e., whenever needed. The momentum booster  80  includes a relatively flat, weighted ring or disc  82  mounted inside the rear bicycle wheel via equidistantly spaced holders  84 . The holders  84  may be rectangular blocks that project a small distance past the circumferential edge of the weighted ring  82  so that the virtual diameter of the holders  84  are equal to or slightly greater than the inner diameter of the rear bicycle wheel. With this configuration, the holders  84  may be used to press fit the weighted ring  82  inside the rear bicycle wheel. However, the press fit may not be sufficient to keep the weighted ring  82  in place. To overcome this potentiality, the momentum booster  80  includes a plurality of holder straps  86  angularly spaced around the weighted ring  82 . Each strap  86  straddles a pair of spokes  90  and secures the weighted ring  82  to the spokes  90  via fasteners  88 . Thus, the weighted disc  82  is securely mounted to the rear bicycle wheel by press fit engagement of the holders  84  and by the holder straps  86 . 
         [0030]    The momentum booster  80  functions similarly to the momentum booster  50 . The rotation of the weighted ring  82  during pedaling produces additional rotational momentum from inertia or a flywheel effect. This, in combination with the rotational momentum from the outer disc  20 , ensures that momentum can be sustained for a longer period of time than by the outer disc  20  alone. 
         [0031]    The bicycle pedaling system  10  may encompass a variety of alternatives. For example, the weight of the outer disc  20  may vary by material composition and density. The outer disc  20  may be relatively thin, with detachable weights mounted to the rims thereof. Moreover, the outer disc  20  may be fabricated to have varying density, low to high, in the radial direction. All the components of the bicycle pedaling system  10  including the momentum boosters  50  and  80  may be made from durable steel, plastic, wood or combination thereof. The spring-loaded pawl  46  may use any durable spring that maintains long lasting operative position of the pawl  46 , or the pawl  46  itself may be made from a resilient material, i.e., the pawl  46  may be a leaf spring. 
         [0032]    It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.