Patent Publication Number: US-2007114086-A1

Title: Vehicle propulsion system and vehicles adapted to include propulsion system

Description:
The present invention relates generally to a vehicle propulsion system and to vehicles adapted to include such a propulsion system.  
      A conventional bicycle  21  is shown in  FIG. 1 . The bicycle  21  has a frame  23  that ordinarily defines a generally planar shape. The frame  23  comprises a top tube  25 , a down tube  27 , a head tube  29  to which both the top tube and down tube are secured, such as by brazing, and a seat tube  31  that is secured to a rear end of the top tube and, at a bottom bracket  33 , to the down tube. A front fork  35  is pivotably attached to the head tube  29 , and a head set  37  comprising a stem  39  that is secured to a top steering column portion of the front fork at the top end of the head tube. A handlebar  41  is attached to the stem  39 . A rider turns a front wheel  43  attached to the front fork  35  relative to a plane defined by the frame  23  by turning the handlebar  41  which, in turn, turns the stem  39  and the front fork.  
      An axle (not shown) extends through and is rotatably mounted to the bottom bracket  33  in rotary bearings (not shown). The axle extends perpendicular to the plane of the frame  23 . Left and right cranks  44  are attached to opposite ends of the axle on opposite sides of the bottom bracket  33  and extend generally perpendicularly to the axle. Pedals  45  are typically attached to the cranks  44 . One or more chain wheels  47  are non-rotatably secured to the axle, such as by a “spider”  49 .  
      A rear wheel  51  is rotatably secured to a portion of the frame  23  at an end of a chain stay  53  by an arrangement referred to as a freewheel  55  which permits a driving force to be transmitted to the rear wheel in one rotation direction only. Different types of freewheels are available, such as those described in U.S. Pat. No. 5,186,377, which is incorporated by reference. An endless chain  59  extends around the chain wheels  47  and the freewheel gears  57  attached to an outer part (not shown) of the freewheel  55 . Typically, the outer part of the freewheel  55  spins freely in one direction (e.g., counter-clockwise when the bicycle is viewed from the right side) relative to an inner part (not shown) which can be fixed to a hub of the rear wheel  51 . Thus, when a rider pedals backwards, the rear wheel is not forced to rotate backwards and, when the rear wheel is turning clockwise, the rear wheel does not cause the cranks  44  to rotate, i.e., the rider can coast. The outer part of the freewheel  55  locks when turned in the other direction (clockwise) relative to the inner part. Thus, when a rider pedals in one direction and thereby causes the chain wheels  47  to turn clockwise, the chain  59  is turned clockwise, which turns the freewheel gears  57 , the inner and outer parts of the freewheel  55 , and the rear wheel  51  clockwise, thus propelling the bicycle forward.  
      It is desirable to provide a bicycle or similar vehicle with a propulsion system that facilitates the use of the rider&#39;s arms to propel the vehicle, either with or without the use of the rider&#39;s legs.  
      In accordance with an aspect of the present invention, a propulsion system comprises a first torque transmission element, a second torque transmission element, the first torque transmission element being adapted to transmit torque to the second torque transmission element, and a first torque transmission element crank coupled to the first torque transmission element by a bearing arrangement that transmits torque to the first torque transmission element when the first torque transmission element crank is turned in a first rotational direction about an axis of the first torque transmission element and that permits the first crank to be turned freely relative to the first torque transmission element when the first torque transmission element crank is turned in a second rotational direction.  
      In accordance with another aspect of the present invention, a rider propelled vehicle comprises a vehicle frame including a bracket, a wheel rotatably mounted on the vehicle frame, and a propulsion system attached to the bracket. The propulsion system comprises a first torque transmission element, and a first torque transmission element crank coupled to the first torque transmission element by a freewheel that transmits torque to the first torque transmission element when the first torque transmission element crank is turned in a first rotational direction about an axis of the first torque transmission element and that permits the first torque transmission element crank to be turned freely relative to the first torque transmission element when the first torque transmission element crank is turned in a second rotational direction, and a second torque transmission element, the first torque transmission element being adapted to transmit torque to the second torque transmission element. The vehicle further comprises a chain wheel coupled to the second torque transmission element, the second torque transmission element being coupled to the chain wheel such that torque is transmitted between the second torque transmission element and the chain wheel when the first torque transmission element is turned in the first rotational direction, a sprocket attached to the wheel, and an endless chain extending around the chain wheel and the sprocket.  
      In accordance with another aspect of the present invention, a bicycle comprises a frame comprising a top tube, a down tube, and a seat tube connected between the top tube and the down tube, a fork comprising a steering column, and a head tube assembly comprising a steering yoke attached to the top tube and the down tube, a stem and a bottom plate pivotably attached to a top end and a bottom end of the steering yoke, respectively, a tube attached at top and bottom ends thereof to the stem and the bottom plate, respectively, the steering column extending into and being fixed relative to the tube.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The features and advantages of the present invention are well understood by reading the following detailed description in conjunction with the drawings in which like numerals indicate similar elements and in which:  
       FIG. 1  is a side view of a conventional bicycle;  
       FIG. 2  is a side view of a vehicle including a propulsion system according to an embodiment of the present invention;  
       FIG. 3  is a side, partially cross-sectional view of a portion of a vehicle including a propulsion system according to an embodiment of the present invention;  
       FIG. 4  is a side, partially cross-sectional view of a portion of a propulsion system according to an embodiment of the present invention;  
       FIG. 5  is a top, partially cross-sectional view of a portion of a propulsion system according to an embodiment of the present invention;  
       FIG. 6  is an exploded, partially cross-sectional view of a portion of a propulsion system according to an embodiment of the present invention;  
       FIG. 7A  is a side, partially cross-sectional view of a head assembly according to an embodiment of the present invention;  
       FIG. 7B  is a top view of portions of a head assembly;  
       FIG. 7C  is a top, cross-sectional view of the head assembly of  FIG. 7A  taken at section  7 C- 7 C;  
       FIG. 8  is a side view of a portion of a head assembly according to an embodiment of the present invention;  
       FIG. 9  is a front view of a yoke of a head assembly according to an embodiment of the present invention;  
       FIG. 10  is a rear view of a yoke of a head assembly according to an embodiment of the present invention;  
       FIG. 11  is an exploded view of portions of a head assembly according to an embodiment of the present invention;  
       FIG. 12  is a top view of a steering arrangement according to an embodiment of the present invention;  
       FIG. 13  is a top view of the steering arrangement of  FIG. 12  with levers of the arrangement removed; and  
       FIG. 14  is a top view of a steering arrangement according to another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION  
       FIG. 2  shows a bicycle  121  according to an embodiment of the present invention. The bicycle  121  comprises a propulsion system  123  according to an embodiment of the present invention. The bicycle  121  is in many respects similar to conventional bicycles such as the bicycle  21  described in connection with  FIG. 1 . However, the propulsion system  123  facilitates use of the rider&#39;s arms to propel or assist in propelling the bicycle. In the illustrated embodiment, the rider pivots a specially adapted arm or lever arrangement  125  that can be similar in appearance to and function like conventional “aerobars”. The propulsion system  123  includes an arrangement coupling the lever arrangement  125  ultimately to the pedal axle (not shown in  FIG. 2 ) so that pivoting of the levers causes the chain  127  to turn and drive the rear wheel  129 .  
      Basic features of a propulsion system  123  according to an embodiment of the present invention are seen in  FIGS. 3-6 . The propulsion system  123  comprises torque transmission elements such as a first gear  131  and a second gear  133 , it being understood that other forms of torque transmission elements could be used instead of gears, such as rollers and belts, and sprockets and chains. However, for purposes of describing torque transmitting elements in an embodiment of the present invention, gears are used as an example.  
      Teeth  135  and  137  of the first gear  131  and the second gear  133  mesh. A first gear crank  139  is coupled to the first gear  131  by an arrangement including a freewheel or freewheel-type bearing arrangement such as a roller clutch that transmits torque to the first gear when the first gear crank is turned in a first rotational direction RD 1  ( FIG. 4 ) about an axis A 1  of the first gear and that permits the first crank to be turned freely relative to the first gear when the first gear crank is turned in a second rotational direction RD 2  ( FIG. 4 ).  
      The second first gear crank  143  can be coupled to the first gear  131  by an arrangement including a freewheel or freewheel-type bearing arrangement as seen in the exploded view in  FIG. 6  that transmits torque to the first gear when the second first gear crank is turned in the first rotational direction RD 1  about the axis A 1  of the first gear and that permits the second first gear crank to be turned freely relative to the first gear when the second first gear crank is turned in the second rotational direction. Ordinarily, the second first gear crank  143  will be disposed on an opposite side of the first gear  131  than the first gear crank  139 , and will be coupled to the first gear by a different bearing arrangement than the first gear, however, the first gear crank and the second first gear crank can be disposed on the same side of the first gear and/or can be coupled to the first gear by the same bearing arrangement.  
      A second gear crank  147  ( FIG. 2 ) is coupled to the second gear  133 , such as by an axle  149 . The second gear crank  147  can be coupled to the second gear  133  by an arrangement including a freewheel or freewheel-type bearing arrangement (not shown) that transmits torque between the axle and the second gear only when the second gear crank is turned in the second rotational direction RD 2 . Ordinarily, the second gear crank  147  is coupled to the second gear  133  such that torque is transmitted to the second gear when the second gear crank is turned in either the first or the second rotational directions RD 1  or RD 2 , such as by a non-circular portion  151  ( FIG. 6 ) of the axle  149  being received in a corresponding non-circular opening (not shown) in the second gear.  
      The propulsion system  123  shown in  FIGS. 3-6  is largely disposed inside of a housing  153  including a housing cover  155 . The second gear  133  and the axle  149  can be held in position relative to the housing  153  and cover  155  by freewheel-type bearing arrangements such as left and right roller clutches  157  and  159  and, if desired, rings  161  and bushings  163  fixed between the inner surfaces of the roller clutches and the outer surface of the axle  149 . Radially inner portions (not shown) of the roller clutches  157  and  159  are ordinarily non-rotatable or substantially non-rotatable relative to the axle  149  while radially outer portions are rotatable in one direction and non-rotatable in another direction such that torque is transmitted between the axle and the outer portion of the roller clutches only when the second gear crank  147  is turned in the second rotational direction RD 2 .  
      Outer portions  157   o  and  159   o  of the left and right roller clutches  157  and  159  are ordinarily non-rotatable relative to left and right clutch housings  165  and  167 . The left and right clutch housings  165  and  167  and the second gear  133  are secured in axial positions by left and right inner bearings  169  and  171  mounted the axle  149  and sandwiching the left and right clutch housings and the second gear. The left and right inner bearings  169  and  171  are received in left and right recesses  173  and  175  ( FIG. 5 ) in the left and right clutch housings  165  and  167 , respectively, and permit free rotation of the axle  149  relative to the left and right clutch housings. The left and right clutch housings  165  and  167  are held in position relative to the housing  153  and the cover  155  by left and right outer bearings  177  and  179 . An internally threaded portion  181  of a spider  183  or a chainwheel is secured to an externally threaded portion  185  of the right clutch housing  167 . The cover  155  includes a cap  187  with an externally threaded portion  189  that mates with an internally threaded portion  191  of the housing cover. The left bearing  177  abuts an extending flange portion  193  of the cap  187  and the right bearing  179  abuts an extending flange portion  195  of a housing cap  196  with external threads that mate with internal threads on an opening in the housing  153 . The cover cap  187  and the housing cap  196  assist in holding the second gear  133 , axle  149  and associated components in place in the housing  153 . The cover  155  is secured to the housing  153  in any suitable manner, such as by bolts (not shown) that extend through holes in the cover into threaded openings in the housing. Pedals  197  ( FIG. 2 ) are typically attached to second gear cranks  147  on opposite ends of the axle  149 .  
      Turning to the first gear  131  and the first gear crank  139  and the second first gear crank  143 , a pin  199  extends through and is non-rotatable relative to the first gear  131 , such as by having a non-circular cross-section that is received in a corresponding non-circular opening in the gear, by providing a key (not shown), or the like. The pin  199  defines the axis A 1  of the first gear  131 . The pin  199  is fixed to inner portions of freewheel-type bearing arrangements such as left and right roller clutches  201  and  203  on opposite sides of the first gear  131 . As with the roller clutches  165  and  167 , structures such as rings  205  and bushings can be disposed between the inner surfaces of the roller clutches  201  and  203  and the outer surface of the pin  199 . Outer surfaces  201   o  and  203   o  of the left and right roller clutches  201  and  203  are attached to inner surfaces of left and right arm clutch housings  207  and  209 . The left and right arm clutch housings  207  and  209  are axially fixed in position and are ordinarily freely rotatable (and at least pivotable) relative to the housing  153  and cover  155  by means of left and right outer bearings  211  and  213  between the left and right arm clutch housings and supporting surfaces of the housing and the cover. The left and right arm clutch housings  207  and  209  have the first gear crank  139  and the second first gear crank  143  extending therefrom, respectively. The first gear crank  139  and the second first gear crank  143  can be formed integrally with the left and right arm clutch housings or can be fixed to them by any suitable means, such as by fasteners, adhesive, and the like.  
      By pivoting the first gear crank  139  and the second first gear crank  143 , the left and right arm clutch housings  207  and  209  pivot, respectively. When the left and right arm clutch housings  207  and  209  pivot, the outer portions  201   o  and  203   o  of the left and right roller clutches  201  and  203  pivot, respectively.  
      When the first gear crank  139  and the second first gear crank  143  pivot in the first rotational direction RD 1 , the left and right roller clutches  201  and  203 —inner and outer portions—pivot in the first rotational direction, and cause the pin  199  to pivot in the first rotational direction about the axis A 1 . The pivoting of the pin  199  about the axis A 1  causes the first gear  131  to pivot in the first rotational direction about the axis A 1 .  
      By contrast, when the first gear crank  139  and the second first gear crank  143  pivot in the second rotational direction RD 2 , only the outer portions  201   o  and  203   o  of the left and right roller clutches  201  and  203  pivot in the second rotational direction. The inner portions of the left and right roller clutches  201  and  203  do not pivot, and the pin  199  does not pivot about the axis A 1 . Thus, by pivoting the first gear crank  139  and the second first gear crank  143  in the first rotational direction, torque is transmitted to the first gear. Torque is not transmitted when the first gear crank  139  and the second first gear crank  143  are pivoted in the second rotational direction RD 2 . Thus, reciprocating piston-like movements of the first gear crank  139  and the second first gear crank  143  can transmit torque from the first gear crank and the second first gear crank to the first gear  131 . The first gear  131  turns the second gear  133  which can be used to drive the rear wheel  129 . Thus, a rider can drive the rear wheel  129  by: turning the second gear crank  147  as in a conventional bicycle; reciprocating one or both of the first gear crank  139  and the second first gear crank  143 ; or both turning the second gear crank and reciprocating one or both of the first gear crank and the second first gear crank.  
      The propulsion system  123  has been described in connection with an embodiment wherein a first gear crank  139  and a second gear crank  143  are disposed on opposite, or left and right, sides of a first gear  131 , and wherein clutch housings  165  and  167  and other components are disposed on left and right sides of a second gear  133 . It will be appreciated, however, that all components can be disposed on a right or a left side of the gears, and that, instead of providing two, i.e., left and right, sets of components, the power transmission can be operated with one set of the components described, or with additional sets of components, as desired.  
      In addition, while the propulsion system  123  has been described in connection with an embodiment wherein torque is transmitted between two gears, additional torque transmitting elements may be provided. For example, a plurality of sprockets and a chain might be provided instead of the first and/or the second gears, and gear ratios between sprockets can be shifted in substantially the same manner that gear ratios are shifted between the chainwheel and the freewheel gears on a conventional bicycle. Further, the torque transmitting elements need not necessarily transmit torque in a single direction, i.e., torque transmitting elements such as helical gears having rotational axes disposed at angles relative to each another may be used.  
      As seen in  FIGS. 2 and 3 , the bicycle  121  comprising the propulsion system  123  has a frame  215  comprising a top tube  217 , a down tube  219 , a seat tube  221 , and a chain stay  223 . A chainwheel  225  ( FIG. 2 ) is mounted to the spider  183 , a freewheel  227  with one or more freewheel gears  229  is disposed at an end of the chain stay  223 , and a chain  231  extends around the chainwheel and the freewheel gear or gears. The gear ratios between one or more chainwheel sprockets and one or more freewheel gears can be shifted in any suitable conventional manner. The rear wheel  129  is mounted at the end of the chain stay  223  in the conventional manner.  
       FIGS. 2-3  show a conventional bicycle modified so that the down tube  219 , the seat tube  221 , and the chain stay  223  are secured to a specially provided housing  153  for the propulsion system  123 . The tubes may be secured to the housing in any suitable manner, such as by being received in tubular openings provided for the tubes and secured in place by welding, brazing, adhesives, mechanical fasteners, or the like. Of course, a bicycle frame may be specially made for the components of the propulsion system  123  such that they need not necessarily be disposed in a housing as described here.  
      As seen in  FIG. 4 , a crank rod  233  is pivotably attached to the first gear crank  139  remote from the axis A 1  of the first gear  131 . The crank rod  233  extends out of the housing  153  and into one end of the down tube  219  and, ordinarily, out the other, where it can be pivotably attached to a pivot member  235  ( FIG. 9 ) that will ordinarily be pivotably attached to a component of the bicycle frame  215 . A lever  237  ( FIGS. 8 and 11 ) of the lever arrangement  125  is also pivotably mounted relative to the frame  215  and linked to the crank rod  233 , ordinarily by the pivot member  235  and a linkage member  239 , such that pivotal movement of the lever is adapted to turn the first gear crank  139  in the first rotational direction. The lever  237  is ordinarily mounted indirectly to the frame  215 .  
      A single crank rod  233  can be used to turn both the first gear crank  139  and the second first gear crank  143 , however, ordinarily a left and a right crank rod  233  and  241  are pivotably connected to the first gear crank and the second first gear crank, respectively. As seen generally in  FIGS. 3 and 7 A- 11 , the left and the right crank rods  233  and  241  are linked to left and right levers  237  and  243 , respectively, by left and right pivot members  235  and  245  and left and right pivot members  239  and  247 .  
      Pivotal movement of the levers  237  and  243  in one of the first or second lever rotational directions RDL 1  and RDL 2  turns the first gear crank  139  and the second first gear crank  143  in the first rotational directions RD 1 , while turning the levers in the opposite direction does not turn the first gear crank. In the illustrated embodiment, turning the levers  237  and  243  in the first lever rotational direction RDL 1  turns the first gear crank  139  and the second first gear crank  143  in the first rotational direction RD 1 , and the first lever rotational direction and the first rotational direction are the same rotational directions in the same planes. The right lever  243  moves in the first lever rotational direction RDL 1  from the position illustrated in  FIG. 7A  to the position illustrated in  FIG. 8 . As it does so, the linkage  247  is caused to move upward and pivots the pivot member  245  which, in turn, pulls on the right hand crank rod  241 . It will be appreciated, however, that the levers can be linked to the first gear crank and the second first gear crank by a variety of different linkage arrangements such that rotation of the levers in the second lever rotational direction turns the first gear crank and the second first gear crank in the first rotational direction, and the second lever rotational direction may be in a plane different than the plane of the first rotational direction.  
      While the illustrated embodiment shows levers  237  and  243  linked to the crank rods  233  and  241  by a pivot member  235  and  245  and a linkage member  239  and  247 , it will be appreciated that the levers can be pivotably connected directly to the crank rods. While the illustrated embodiment shows crank rods  233  and  241  extending through the down tube  219 , the crank rods may be disposed outside of the downtube. If a housing is provided, the crank rods may extend into the housing through openings for the crank rods.  
      The left and right levers  237  and  243  are pivotably mounted to the bicycle  121 . In the illustrated embodiment, the levers are pivotably mounted to a specially adapted head assembly  249 , as seen in  FIGS. 7A-8  and  10 . The head assembly  249  comprises a steering yoke  251  attached to the top tube  217  and the down tube  219 . The top tube  217  and the down tube  219  can be connected in any suitable manner, much like the down tube, the seat tube  221 , and the chain stay  223  are connected to the housing  153 . For example,  FIGS. 7A and 10  show openings  249   o   1  and  249   o   2  in which the top tube  217  and the down tube  219  can be secured. In the illustrated embodiment, the crank rods  233  and  241  extend out of the down tube  219  and are pivotably attached to pivot members  235  and  245  that are pivotably attached to the steering yoke  251 .  
      The head assembly  249  further comprises what shall be referred to as a stem  253  and a bottom plate  255  pivotably attached to a top end  257  and a bottom end  259  of the steering yoke, respectively, and a tube  261  attached at top and bottom ends thereof to the stem and the bottom plate, respectively. A steering column  263  of a fork assembly  265  extends into and is fixed relative to the tube  261  in any suitable manner, such as by a nut and washer arrangement  267  attachable around a threaded end  269  of the steering column, and that secures the fork assembly relative to the stem  253 . The stem  253  and the bottom plate  255  can be pivotably attached to the top end  257  and the bottom end  259  of the steering yoke  251  in any suitable manner, such as by a top bearing  271  and spool  273  receivable in openings (not shown) in the top end of the steering yoke and the stem, and a bottom bearing  275  and spool  277  receivable in openings (not shown in the bottom end of the steering yoke and the bottom plate.  
      The linkages  239  and  247  can extend from the pivot members  235  and  245  through the top bearing  271  and spool  273  and can be pivotably connected to the levers  237  and  243 . The levers  237  and  243  can, in turn, be pivotably connected to the stem  251  at some point remote from the point at which the linkage members  239  and  243  are pivotably attached. The levers  237  and  243  can take any desired form, such as being in a shape and position to function like aerobars. By providing the linkages  239  and  247  in the form of eye bolts that mate with internally threaded rods as seen in  FIG. 7A , as seen in  FIG. 7B , the tube  261  and fork  265  can be moved a substantial amount about an axis AY extending through the yoke  251 .  
      As seen in  FIG. 12  additional components  279  may be attached to the levers  237  and  243  for this purpose, including gear shifting and brake components. The particular additional components shown in  FIG. 12  are aerobar extensions  279   a  that adapt the levers to function substantially like aerobars. As seen in  FIGS. 12 and 13 , a separate handlebar  281  may be secured to the stem  251 , as well. Other components such as gearshift and brake components may be mounted on the levers, aerobars, or handlebars, if desired.  FIG. 14  shows an alternative arrangement wherein handlebar extensions  281   a  are provided on the levers  237  and  243 . Thus, embodiments of a steering arrangement on a bicycle, for example, may comprise handlebars together with levers and aerobar extensions, aerobar extensions on the levers alone, handlebar extensions on the lever alone or with handlebars, to name but a few possibilities.  
      As seen in  FIG. 11 , a bottom lock nut  283  can be provided to assist in securing a threaded bottom end  261   b  of the tube  261  to the bottom plate  255 . A threaded top end  261   t  of the tube  261  can be screwed into an internally threaded extending portion  253   e  of the stem. Steering of a front wheel  285  ( FIG. 2 ) mounted to the fork  265  can be accomplished either by turning the handlebar  281  or by turning the levers  237  and  243  relative to the frame  215 . A yoke cover  251   c  ( FIG. 11 ) can be provided to cover the left and right pivot members  235  and  245  and portions of the left and right crank rods  233  and  241  and portions of the left and right linkages  239  and  247 .  
      While the present invention has been described largely in connection with its use in a bicycle, it will be appreciated that the present invention has numerous applications, such as for use on exercise equipment, wheelchairs, or other rider-propelled devices.  
      While the present invention has been described largely in connection with an embodiment wherein gears are used as torque transmission elements, it will be noted that torque transmission occurs differently in other forms of torque transmission elements such as wheels and belts or sprockets and chains. Two adjacent gears will ordinarily transmit torque by turning in opposite rotational directions, while two connected sprockets or wheels will ordinarily transmit torque by turning in the same rotational direction. If torque transmission elements are used that transmit torque by turning in the same direction, then it may be desirable to reverse the orientation of freewheel-type bearing arrangements corresponding to one of the elements.  
      In the present application, the use of terms such as “including” is open-ended and is intended to have the same meaning as terms such as “comprising” and not preclude the presence of other structure, material, or acts. Similarly, though the use of terms such as “can” or “may” is intended to be open-ended and to reflect that structure, material, or acts are not necessary, the failure to use such terms is not intended to reflect that structure, material, or acts are essential. To the extent that structure, material, or acts are presently considered to be essential, they are identified as such.  
      While this invention has been illustrated and described in accordance with a preferred embodiment, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims.