Abstract:
A rear wheel hub and chainless drive train gear assembly for use on a bicycle having an axle bracket fixed to the frame of the bicycle, a spindle extending axially through the axle bracket and left and right pedal crank arms for rotating the spindle upon application of a pedaling force. A primary drive gear fitted to the spindle drivingly engages carrier gears which operate a planet gear cage housing and a multiple planetary gear and sun gear arrangement according to various gear ratios determined by selective operation of a clutch assembly. Planetary gear groups each include an integral set of planetary gears of varying size which mesh with corresponding sun gear rings. Operation of the clutch assembly serves to selectively engage pawl stops with a corresponding sun gear ring, thereby engaging the corresponding sun gear ring with one of the planetary gears of the planetary gear groups according to a selected gear ratio. The planetary gear groups drive an annular gear ring and an associated annular needle bearing which, in a forward clockwise rotation, engages the hub body to rotate the rear bicycle wheel. Reverse rotation of the annular gear, in a counter-clockwise rotation, results in a freewheeling of the drive train gear assembly relative to the hub body.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a rear wheel hub and drive train assembly for a bicycle and, more particularly, to a rear wheel hub and chainless drive train gear assembly which is operable in conjunction with a spindle, crank arms and pedals to drivingly rotate the rear wheel of a bicycle at either a single speed or at multiple selected speeds. 
     2. Discussion of the Related Art 
     The drive train design of most bicycles incorporates a chain connected between a sprocket and a gear assembly near the rear wheel hub. Typically, the sprocket is fitted to an axle extending through a bearing on the bicycle frame between the front and rear wheels. The sprocket, driven directly by pedals attached to crank arms, rotates to move the chain about a loop between the sprocket and the gear assembly. On multi-speed bicycles, having several different gear speeds, a derailer is provided for moving the chain among various sized gears at the gear assembly near the rear wheel hub. Derailers, which are typically operated by a cable and control on the handlebars, have been known to be problematic. On many occasions, the derailer will not successfully move the chain from one gear size to the next, causing the chain to become “derailed” in disengagement with the gear assembly. When this happens, the bicycle rider is required to manually place the chain back into engagement with teeth on one of the gears near the rear wheel, and then, upon rotating the pedals, the chain is fully becomes re-engaged with the gears. This process can sometimes by frustrating and messy, causing the bicycle rider&#39;s hands to be covered with grease from the chain. Also, because the chain and gear assembly are openly exposed to the environment, sand, dirt and other debris eventually attach to the grease on the chain and gears, causing excessive grinding and wear of both the chain and gears. This can also interfere with effective engagement of the chain between the various gear sizes when switching between gear speeds. A further problem resulting from the exposed nature of the chain driven drive train assemblies of bicycles is entanglement of clothing, shoelaces, and other articles with the chain and the sprocket gear and/or rear gear assembly. 
     Chain driven drive gear assemblies present a further problem of adding extra weight to the bicycle. Specifically, the requirement of a sprocket gear, sprocket bearing, and chain add extra weight to the bicycle. Moreover, the positioning of the sprocket and pedals requires significant spacing between the front and rear wheels, thereby requiring a longer frame to separate the front and rear wheels. This also adds to the weight of the bicycle, which is undesirable, particularly, in competitive bicycling sports, such as racing and acrobatics. 
     In an attempt to improve the gear systems on bicycles, others have proposed various mechanisms and apparatus for increasing the efficiency and longevity of the drive train assembly. In particular, the U.S. patent to Nagano, U. S. Pat. No. 5,273,500, discloses a self-contained change speed apparatus for use on a bicycle. The apparatus in Nagano includes a drive member and a hub body rotatably supported on a fixed shaft, and two planetary gear mechanisms arranged on a drive transmission path extending from the drive member to the hub body. The drive member has a chain wheel or gear which is driven by a drive chain. The drive chain extends to a forwardly positioned sprocket and pedal assembly, of a conventional arrangement. Accordingly, while the Nagano apparatus provides an improvement to the gear arrangement and assembly on the bicycle for changing speeds, the problems associated with a chain driven drive train assembly remain unsolved. 
     Accordingly, in view of the problems and shortcomings of the various drive train gear assemblies in the bicycle art, there still remains an urgent need for an improved, chainless drive train assembly which is incorporated within the rear wheel hub of a bicycle and in direct, axial driven engagement with the pedals and crank arms of the bicycle. 
     OBJECTS AND ADVANTAGES OF THE PRESENT INVENTION 
     With the foregoing in mind, it is a primary object of the present invention to provide an improved drive train assembly for use on bicycles which eliminates the use of a chain. 
     It is also a primary object of the present invention to provide an improved driven train assembly for bicycles which is incorporated within the rear wheel hub and which further includes an axial spindle which is concentric with the rear wheel hub and drive train gear assembly and which is driven directly by crank arms and pedals without the use of a chain. 
     It is still a further object of the present invention to provide a rear wheel hub and chainless drive train gear assembly which enables closer spacing of the front and rear wheels of a bicycle, thereby reducing weight of the bicycle. 
     It is still a further object of the present invention to provide a rear wheel hub and chainless drive train gear assembly for a bicycle which is specifically structured and disposed to permit optimal positioning of the bicycle rider relative to the rear wheel of the bicycle. 
     It is still a further object of the present invention to provide a rear wheel hub and chainless drive train gear assembly which is structured and disposed to permit a bicycle rider to pedal the bicycle while seated at an advantageous posture. 
     It is still a further object of the present invention to provide a rear wheel hub and drive train gear assembly which is adapted for use in conjunction with a bicycle having an adjustable chest rest and an adjustable handle bar, to enable positioning of the bicycle rider at an optimal posture, thereby reducing wind resistance, muscle fatigue and the likelihood of injury, while increasing the bicycle rider&#39;s output and performance. 
     These and other objects and advantages of the present invention are more readily apparent with reference to the detailed description and accompanying drawings. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a rear wheel hub and drive train gear assembly for use on a bicycle having a hub axle bracket shell fixed to the frame of the bicycle, a spindle extending axially through the hub axle bracket shell and rotatable therein upon application of a pedaling force transmitted through left and right crank arms attached to opposite ends of the spindle. A primary drive gear fitted to the spindle drivingly engages carrier gears which operate a planet gear cage housing and multiple planetary gear and sun gear arrangement according to various gear ratios determined by selectively operation of a clutch assembly. Direct attachment of the pedal operated crank arms to the spindle provides a chainless drive train assembly for rotating the rear bicycle wheel. Planetary gear groups each include an integral set of planetary gears of varying size which mesh with corresponding sun gear rings. Operation of the clutch assembly serves to selectively engagement pawl stops with a corresponding sun gear ring, thereby engaging the corresponding sun gear ring with the planetary gear of the planetary gear groups. The planetary gear groups drive an annular gear ring and an associated annular needle bearing which, in a forward clockwise rotation, engages the hub body to rotate the rear bicycle wheel. Reverse rotation of the annular gear, in a counterclockwise rotation, results in a freewheeling of the drive train gear assembly relative to the hub body. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a fuller understanding of the nature of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is an external perspective view of the assembled rear wheel hub and drive train gear assembly with crank arms attached; 
     FIG. 2 is a perspective view showing the spindle and attached crank arms of the invention; 
     FIG. 3 is a perspective view showing the spindle with a primary drive gear, carrier gears, and bearings fitted thereto; 
     FIG. 4 is a perspective view, in partial cutaway, showing the spindle extending axially through a hub axle bottom bracket shell of the assembly; 
     FIG. 5 is a perspective view, in partial cutaway, showing the spindle, primary drive gear, carrier gears, and hub axle bottom bracket shell assembled; 
     FIG. 6 is a perspective view showing a clutch assembly fitted to the combined assembly of FIG. 5; 
     FIG. 7 is a perspective view showing a sun ring pawl and planetary gear assembly fitted about the clutch assembly on the hub axle bottom bracket shell; 
     FIG. 8 is a perspective view showing a planetary gear cage fitted about the planetary gear assembly; 
     FIG. 9 is a perspective view illustrating a further assembled stage of the invention wherein an annular gear ring is fitted about the planetary gear cage; 
     FIG. 10 is a perspective view showing the assembly of FIG. 9 from an opposite end; 
     FIG. 11 is a left, front perspective view, in partial cross section, showing the drive train gear assembly fully assembled with the hub body removed; 
     FIG. 12 is a right, front perspective view, in partial cross section, illustrating the drive train gear assembly fully assembled with the hub body removed; 
     FIG. 13 is a right, front perspective view, in partial cross section, showing the hub axle bottom bracket shell, clutch assembly, and sun gear ring pawl and planetary gear assembly relative to the main drive gear and carrier gears; 
     FIG. 14 is a right, front perspective view, in partial cross section, showing the identical assembly of FIG. 13 with one of the planetary gear groups removed to better illustrate pawls on the sun gear ring pawls; 
     FIG. 15 is a left, front perspective view, in partial cross section, showing the assembly of FIG. 13; 
     FIG. 16 is a side elevational view of a bicycle with the rear wheel hub and drive train gear assembly of the present invention; 
     FIG. 17 is a side elevational view illustrating various positions of a rider of the bicycle using the hub and drive gear assembly of the present invention in conjunction with an adjustable chest rest and an adjustable handle bar on the bicycle; 
     FIG. 18 is an exploded right perspective view showing the separated components of the drive train gear assembly of the present invention; and 
     FIG. 19 is an exploded left perspective view showing the separated components of the drive train gear assembly of the present invention. 
    
    
     Like reference numerals refer to like parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the several views of the drawings, and initially FIGS. 1-5, the hub and drive train gear assembly of the present invention is shown and is generally indicated as  8 . The assembly  8  includes a hub body  10  which provides a shell about the spindle  12  and drive train gear assembly, while also providing a means for attachment of radiating spokes for supporting a rim of a bicycle wheel, as seen in FIGS. 16 and 17. The hub body  10  is fixed to the bicycle frame through a hub axle bottom bracket shell  20 , as seen in FIG.  4 . The hub axle bottom bracket shell  20  is a non-rotating component which provides a means for attaching the assembly  8  to the frame of the bicycle, while also providing a body for assembly of the components of the drive train gear assembly. Specifically, the components of the drive train gear assembly are assembled both through the hollow interior of the hub axle bottom bracket shell  20  as well as around its exterior. As seen in FIG. 4, spindle  12  extends axially through the hub axle bottom bracket shell  20  and includes opposite distal end portions which extend outwardly beyond the hub axle bottom bracket shell  20 . Crank arms  11  are fixed to the opposite distal ends of the spindle  12  using bolts  19 ,  19 ′. Naturally, pedals are fitted to the opposite free ends of the crank arms to facilitate rotating motion of the crank arms by application of a pedaling force by the bicycle rider. As the crank arms are rotated in a forward driving pedaling motion by the bicycle rider, the crank arms  11  and  11 ′ in turn rotate the spindle  12  along with a multi-spline joint  13  and the main drive gear  14  (see FIGS.  2  and  3 ). Three carrier gears  15 ,  15 ′, and  15 ″ are intermeshed with the primary drive gear at spaced intervals so that upon driven rotation of the drive gear  14 , the three carrier gears  15 ,  15 ′ and  15 ″ are caused to counter-rotate (i.e., rotating in an opposite direction relative to the direction of rotation of the main drive gear). 
     Referring to FIGS. 6-9, the drive train gear assembly further includes a clutch assembly, including a clutch sleeve  29  and a cooperating cone pawl stop  34  which is fixed on the hub axle bottom bracket shell  20 . The clutch sleeve  29  and cone pawl stop  34  are fitted about the central section of the hub axle bottom bracket shell  20 , as best seen in FIG.  6 . The drive train gear assembly further includes sun gear ring pawls  31 ,  32  and  33  received about the clutch sleeve  29  and cone pawl stop  34 , as seen in FIG.  7 . Planetary gear groups  30 ,  30 ′, and  30 ″ drivingly intermesh with respective ones of the sun gear ring pawls  31 ,  32  and  33 . Each planetary gear group includes three planetary gears, including a large planetary gear  30 A, a medium planetary gear  30 B, and a small planetary gear  30 C. 
     As seen in FIG. 8, a planetary gear cage  40  supports each of the planetary gear groups  30 ,  30 ′ and  30 ″ in intermeshing, driving engagement with the respective sun gear ring pawls  31 ,  32  and  33 . Specifically, the planetary gear cage  40  supports the opposite ends of an axle pin  90  which extends axially through each planetary gear group. 
     Referring to FIG. 9, the drive train gear assembly further includes an annular gear ring  42  having an inner annular gear face  42 ″ in driven, intermeshing engagement with the planetary gear groups  30 ,  30 ′,  30 ″, for relative rotation about the planetary gear groups and sun gear ring pawls  31 ,  32  and  33 . An outer annular needle bearing  43  is fitted within the annular gear ring  42  and is structured to be driven by the annular gear ring  42  in one direction, while being further adapted to freewheel when the annular gear ring  42  rotates in an opposite direction. 
     In operation, rotation of the main drive gear  14  serves to counter-rotate the three carrier gears  15 ,  15 ′ and  15 ″. The carrier gears  15 ,  15 ′ and  15 ″ are in driving engagement with a toothed cage gear ring on the side of the planetary gear cage  40 . Counter-rotation of the three carrier gears  15 ,  15 ′ and  15 ″ serves to drivingly rotate the planetary gear cage  40  in the same rotational direction as the primary drive gear  14 . Rotation of the planetary gear cage  40  carries the planetary gear groups  30 ,  30 ′ and  30 ″ about the sun gear ring pawls  31 ,  32  and  33 . Each planetary gear group  30 ,  30 ′ and  30 ″ includes three independent gears of different size, thereby providing three different gear ratios. Specifically, the first planetary gear group  30  includes planetary gears  30 A,  30 B and  30 C. The second planetary gear group  30 ′ includes planetary gears  30 ′A,  30 ′B and  30 ′C. Finally, the third planetary gear group  30 ″ includes planetary gears  30 ″A,  30 ″B and  30 ″C. As mentioned above, each of these planetary gears (A, B and C) in the planetary gear groups provide three different gear ratios. The integral planetary gears are each disposed in driven engagement with three independent respective sun gear ring pawls  31 ,  32  and  33 , as best seen in FIGS. 7 and 8. Specifically, planetary gears  30 A,  30 ′A, and  30 ″A engage sun gear ring pawl  31 . Planetary gears  30 B,  30 ′B and  30 ″B engage sun gear ring pawl  32 . Finally, planetary gears  30 C,  30 ′C and  30 ″C engage sun gear ring pawl  33 . 
     Driven rotation of the primary drive gear  14  when pedaling in the forward (i.e., clockwise motion) serves to engage the drive train assembly to ultimately rotate the hub body  10  including the hub shell  45 , along with the rear wheel of the bicycle. The ratio of revolution of the hub shell  45  and rear bicycle wheel relative to the pedals and crank arms is dependent upon the ratio of revolution of the planetary gear groups  30 ,  30 ′ and  30 ″. More specifically, the gear sizes of each of the planetary gears of the planetary gear groups, as well as the gear size of the outer annular gear face of each of the sun gear ring pawls, work in conjunction to provide a variety of gear ratios to change speeds when pedaling the bicycle. 
     The rider of the bicycle is provided with a control connected to a gear selector shifting cable  25  (see FIG. 6) to facilitate changing speeds. More specifically, operation of the gear control serves to manipulate the gear selector shifting cable  25  to change gears in the following manner. The gear selector shifting cable  25 , when operated, rotates cassette joint pulley  24  approximately 20° from position  20 A to a next position  20 B, defining first gear (see FIG.  6 ). Upon movement of the cassette joint pulley  24  to the first gear position  28 B, the clutch sleeve  29  is rotated approximately 20° (i.e., counter-clockwise) to cause pawl  51  of sun gear ring pawl  31  to engage the pawl stop  34 . This engagement of the pawl  51  with the sun gear ring pawl  31  serves to stop the sun gear  31  from rotating, thus drivingly engaging the planetary gears  30 A,  30 ′A, and  30 ″A with sun gear  31  (see FIGS.  6  and  14 ). Accordingly, the ratio of revolution between the pedals, crank arm and spindle relative to the hub  10  and bicycle wheel is directly related to the gear ratio between planetary gears  30 A,  30 ′A, and  30 ″A and the engaged sun gear  31  when the drive train gear assembly is engaged in first gear, at position  28 B. 
     Further operation of the gear selector shifting cable  25  rotates cassette joint pulley  24  another 20° from position  28 B (i.e., first gear) to position  28 C, defining second gear. Movement of cassette joint pulley  24  to the second gear position in turn rotates the clutch sleeve  29  approximately 20° (i.e., counter-clockwise) to cause pawl  52  of the sun gear ring  32  to engage pawl stop  34 . This engagement causes sun gear ring  32  to be stopped, thereby engaging sun gear ring  32  with planetary gears  30 B,  30 ′B, and  30 ″B. Again, the speed ratio between the crank arms and attached spindle and the hub and bicycle wheel are determined by the gear ratio between planetary gears  30 B,  30 ′B and  30 ″B and the sun gear ring  32 . 
     Further operation of the gear selector shifting cable  25  rotates cassette joint pulley  24  another 20° from second gear position  28 C to position  28 D, defining third gear. Operation of the cassette joint pulley  24  to the third gear position rotates clutch sleeve  29  yet another 20° (i.e., counter-clockwise) causing pawl  53  of the sun gear ring  33  to engage pawl stop  34 . Engagement of pawl  53  with pawl stop  34  stops the sun gear ring  33  from rotating, thus engaging sun gear ring  33  with planetary gears  30 C,  30 ′C, and  30 ″C. Again, the speed ratio is determined by the ratio of revolution of the planetary gears  30 C,  30 ′C,  30 ″C around the sun gear ring  33 . 
     The planetary gear groups  30 ,  30 ′ and  30 ″ and the planetary gear cage  40  rotate at different speeds depending upon which sun gear ring (i.e.,  31 ,  32  or  33 ) is engaged with the planetary gear groups. In other words, if sun gear ring  31  is stopped (i.e., in the first gear position), the planetary gear groups  30 ,  30 ′ and  30 ″, as well as the planetary gear cage  40 , are rotated by the driven engagement between planetary gears  30 A,  30 ′A, and  30 ″A with sun gear ring  31 . Likewise, when the sun gear ring  32  is stopped (i.e., in the second gear position), rotation of the planetary gear groups and planetary gear cage about the sun gear ring assembly is created by driven engagement between planetary gears  30 B,  30 ′B and  30 ″B with sun gear ring  32 . And, finally, driven engagement of sun gear ring  33  with planetary gears  30 C,  30 ′C, and  30 ″C when in the third gear position serves to rotate the planetary gear groups and planetary gear cage at yet another speed. 
     The planetary gear groups  30 ,  30 ′ and  30 ″ are further engaged with annular gear  42  via an intermeshing engagement between planetary gears  30 B,  30 ′B, and  30 ″B and the inner annular gear face  42 ″ of annular gear  42 , as best seen in FIG.  9 . Accordingly, rotation of the planetary gear groups and the planetary gear cage serves to rotate the annular gear  42 . The outer side of the annular gear ring  42  is provided with a teeth ring  42 ′ which includes a plurality of teeth members having a sloped surface and an abrupt shoulder between the next adjacent tooth member. The teeth ring  42 ′ extends about the entire annular gear ring  42 ″ and receives an annular needle bearing therein. The annular needle bearing is provided with a plurality of rollers which are adapted to roll in one direction about the teeth ring  42 ′ traveling over the sloped surfaces of each of the teeth. When the annular gear ring  42  and, accordingly, the teeth ring  42 ′ is rotated in an opposite direction relative to the annular needle bearing  43 , the rollers of the annular needle bearing  43  are caused to engage the abrupt shoulders formed between each of the teeth members of the teeth ring  42 ′. In a clockwise rotation of the annular gear ring  42 , resulting from clockwise driven rotation of the crank arms  11  and attached spindle  12 , the rollers of the outside annular needle bearing  43  engage the teeth ring  42 ′ and further lockingly engage the hub shell  45  surrounding the drive train gear assembly. This results in driven rotation of the hub shell  45  along with the hub body and rear bicycle wheel. In a counter-clockwise rotation of the annular ring gear  42 , caused by counter-clockwise rotation of the pedals, crank arms, and spindle (i.e., in a back pedaling or reverse rotation), the rollers of the outside annular needle bearing  43  disengage with the teeth ring  42 ′ and act as a freewheel, thereby disengaging the drive train gear assembly from the hub shell  45 , the hub body  10  and the rear wheel. 
     In a further embodiment of the present invention, a single speed hub and drive train gear assembly are provided along with the spindle  12  and crank arms  11 ,  11 ′. In this particular embodiment, the planetary gear groups, sun gear rings, and clutch assembly are eliminated. The single speed hub and drive train assembly of this embodiment includes the drive gear  14 , the carrier gears  15 ,  15 ′ and  15 ″ which directly translate the rotational ratio of the drive gear  14  to the hub shell  45  via the annular gear  42 . Again, reverse rotation of the pedals and spindle result in freewheeling, to disengage the drive train gear assembly from the hub shell  45 . 
     While the instant invention has been shown and described in accordance with preferred and practical embodiments thereof, it is recognized that departures from the instant disclosure are contemplated within the spirit and scope of the present invention as defined in the following claims and as interpreted under the doctrine of equivalents.