Abstract:
An improved energy conversion system for propelling a manually powered vehicle is disclosed. The energy conversion system converts the linear kinetic energy applied by an operator to rotational kinetic energy to propel a vehicle. The energy conversion system includes a mechanical stroke multiplier to increase the distance over which the operator may apply a force to the vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from U.S. Provisional Patent Application Ser. No. 61/553,737, filed on Oct. 31, 2011, the entirety of which is expressly incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The subject matter disclosed herein relates to an energy conversion device. More specifically, the present invention relates to a system adapted to convert linear kinetic energy to rotational kinetic energy. Specifically, a preferred embodiment of the present invention converts linear kinetic energy applied by an operator to rotational kinetic energy to propel a vehicle. 
         [0004]    2. Discussion of the Related Art 
         [0005]    As is known to those skilled in the art, human-powered vehicles have been proposed that may be driven by forces applied from either a hand or a foot. Energy may be supplied from a user&#39;s hand, for example, by a rowing motion or by pressing and pulling a lever back and forth. Energy may similarly be supplied from a user&#39;s foot through a rotational, or pedaling, motion or by pressing and releasing a set of foot pedals. 
         [0006]    However, these vehicles are subject to certain limitations. One such limitation is the length of stroke an operator is able to use to apply a force to the vehicle. Rowing motions, for example, are limited to the reach of the operator and leg-pressing motions are limited to the stroke of a leg between a flexed and an extended position. Because the energy transferred from the operator to the vehicle is proportional to both the force applied and the distance over which it is applied, the length of stroke of an operator is a limiting factor in the amount of energy an operator can apply to propel a vehicle. 
         [0007]    Therefore, an energy-conversion system which allows for more energy to be transferred to the output shaft would be desirable. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0008]    Consistent with the foregoing and in accordance with the subject matter as embodied and broadly described herein, a human powered vehicle incorporating a mechanical stroke multiplying system is described in suitable detail to enable one of ordinary skill in the art to make and use the invention. 
         [0009]    An improved energy conversion system for propelling a manually powered vehicle is disclosed. The energy conversion system converts the linear kinetic energy applied by an operator to rotational kinetic energy to propel a vehicle. The energy conversion system includes a mechanical stroke multiplier to increase the distance over which the operator may apply a force to the vehicle. 
         [0010]    According to one embodiment of the invention, a mechanical force multiplier for use in a manually powered vehicle and configured to be mounted to a vehicle frame includes a first member pivotally connected to a first point on the vehicle frame and a second member pivotally connected to a second point on the vehicle frame where the second member is longer than the first member. A force receiving member is operatively connected to the second member and is configured to receive a force from an operator positioned on the vehicle frame. The mechanical force multiplier also includes a rigid section having a first end and a second end. The first end of the rigid section is pivotally connected to each of the first and second members. As the force from the operator is applied to the force receiving member, the second end of the rigid section travels in an arcuate path. 
         [0011]    According to another aspect of the invention, the first end of the rigid section includes a first connection point and a second connection point spaced apart from the first connection point. An end of the first member, distal from the first point on the vehicle frame, is pivotally connected to the first connection point of the first end of the rigid section, and an end of the second member, distal from the second point on the vehicle frame, is pivotally connected to the second connection point of the first end of the rigid section. As the force from the operator is applied to the force receiving member, the first member pivots about the first point on the frame, and as the force from the operator is applied to the force receiving member, the second member pivots about the second point on the frame. As each of the first and second members pivots about its respective points on the vehicle frame, the end of the first member, distal from the first point on the vehicle frame, travels in a shorter arcuate path than the end of the second member, distal from the second point on the vehicle frame such that the rigid section is rotated about the end of the first member distal from the first point on the vehicle frame. 
         [0012]    According to yet another aspect of the invention, the mechanical force multiplier may include a first lever having a first end and a second end. The first end of the first lever is pivotally connected to the vehicle frame, and the second end of the first lever is configured to engage the second end of the rigid section such that the first lever moves between a first position and a second position as the second end of the rigid section travels in the arcuate path. The manually powered vehicle includes a drive train having a rotational drive member and a clutch operatively connected to the rotational drive member. The mechanical force multiplier may further include a second lever having a first end and a second end. The first end of the second lever is connected to the second end of the first lever via a cable, and the second end of the second lever is connected to the clutch to drive the rotational drive member. 
         [0013]    According to another embodiment of the invention, a mechanical force multiplier for multiplying a force applied by a human operator seated on a first frame is disclosed. The mechanical force multiplier includes a rigid frame portion having a first end and a second end, and a pivoting frame portion having a first end and a second end. The first end of the pivoting frame portion is pivotally connected to the first end of the rigid frame portion, and the second end of the pivoting frame portion is pivotally connected to the first frame. A force receiving member is mounted to the pivoting frame and is configured to receive the force applied by the human operator. The first end of the pivoting frame portion travels a first distance responsive to the force applied by the human operator, and the second end of the rigid frame portion travels a second distance responsive to the force applied by the human operator, where the second distance is greater than the first distance. 
         [0014]    According to still another embodiment of the invention, a manually powered vehicle includes a vehicle frame, a chair mounted to the vehicle frame and configured to receive an operator, at least one foot pedal configured to receive a force applied by the operator, and at least one mechanical force multiplier. The mechanical force multiplier includes a rigid frame portion having a first end and a second end, and a pivoting frame portion having a first end and a second end. The first end of the pivoting frame portion is pivotally connected to the first end of the rigid frame portion, the second end of the pivoting frame portion is pivotally connected to the vehicle frame, and one of the foot pedals is mounted to each pivoting frame. The manually powered vehicle also includes at least one of each of the following: a roller, a first lever, a cable, a second lever, and a pulley. Each roller is operatively connected to the second end of the rigid frame portion of one of the mechanical force multipliers. Each first lever has a first end, a second end, and a surface configured to be engaged by the roller. The first end of each of the first levers is pivotally connected to the vehicle frame. Each cable is connected proximate to the second end of one of the first levers. Each second lever has a first end and a second end. The first end of each of the second levers is connected to one of the cables. Each pulley is configured to engage one of the cables extending between the second end of one of the first levers and the first end of one of the second levers. The manually powered vehicle also includes a rotating drive member including at least one clutch and a plurality of wheels. Each clutch is driven by the second end of one of the second levers, and at least one of the wheels is driven by the rotating drive member. 
         [0015]    These and other objects, advantages, and features of the invention will become apparent to those skilled in the art from the detailed description and the accompanying drawings. It should be understood, however, that the detailed description and accompanying drawings, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    Various exemplary embodiments of the subject matter disclosed herein are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout, and in which: 
           [0017]      FIG. 1  is a side elevation view of one embodiment of a human powered vehicle according to the present invention; 
           [0018]      FIG. 2  is a partial side elevation view of the human powered vehicle of  FIG. 1  including the drive members; 
           [0019]      FIG. 3  is a side elevation view of the mechanical multiplier incorporated into the human powered vehicle of  FIG. 1 ; 
           [0020]      FIG. 4  is a side elevation view of the gearing incorporated into the human powered vehicle of  FIG. 1 ; and 
           [0021]      FIG. 5  is a side elevation view of another embodiment of a human powered vehicle according to the present invention; 
       
    
    
       [0022]    In describing the preferred embodiments of the invention which are illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the word “connected”, “attached”, or terms similar thereto are often used. They are not limited to direct connection but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    The various features and advantageous details of the subject matter disclosed herein are explained more fully with reference to the non-limiting embodiments described in detail in the following description. 
         [0024]    Turning initially to  FIG. 1 , a human powered vehicle is designated generally by reference numeral  10 . The vehicle  10  includes a seat  14  configured to receive a human operator (not shown). The seat  14  is mounted to a frame  18 . The frame  18  is configured to receive a plurality of wheels  20 . According to one embodiment of the invention, four wheels  20  are mounted to the frame  18  with two wheels  20  mounted toward a front end  11  of the vehicle  10  on each side  13  of the vehicle  10  and two wheels  20  mounted toward a rear end  12  of the vehicle  10  on each side  13  of the vehicle. Preferably, at least three wheels are mounted to the frame  18  with two wheels  20  mounted toward each side  13  of the vehicle  10  near either the front end  11  or the rear end  12  of the vehicle  10 . It is contemplated that still other numbers and configurations of wheels  20  may be used without deviating from the scope of the invention. A drive train  30  receives a force applied by the operator and transfers the force to at least one of the wheels  20  to propel the vehicle  10 . Referring also to  FIG. 5 , the vehicle  10  may include a roof  200  or canopy mounted to the frame  18  to provide shade and/or protection from inclement weather to the operator. 
         [0025]    According to one embodiment of the invention, the drive train  30  includes two force receiving members, e.g., foot pedals  32 . Each foot pedal  32  is configured to engage one of the operator&#39;s feet and is operatively connected to a mechanical multiplier  50 . The mechanical multiplier  50  is of frame construction and is made from any suitable material but is preferably made from a lightweight material, for example, aluminum or a rigid plastic material. According to one embodiment of the invention, each member of the mechanical multiplier  50  is an elongated bar, which may be solid, tubular, or have a channel extending along the bar, and which has any suitable cross-sectional area such as rectangular, square, circular, or oval. 
         [0026]    Each mechanical multiplier  50  includes a pair of side frames  52  laterally displaced from each other. Each side frame  52  has at least one rigid section, e.g., a first, rigid frame portion  46 , and a second, pivoting frame portion  48 . Each rigid frame portion  46  includes a center post  54  having a first end  56  and a second end  58 , the second end  58  being opposite the first end  56 . The rigid frame portion  46  further includes a first bar  60  and a second bar  61  extending generally in a first direction from the center post  54 . Each of the first and second bars,  60  and  61 , has a first end,  62  and  63  respectively, and a second end,  64  and  65  respectively. Each of the second ends,  64  and  65 , is opposite from the respective first end,  62  and  63 . The first end  62  of the first bar  60  is rigidly mounted proximate to the first end  56  of the center post  54 , and the first end  63  of the second bar  61  is rigidly mounted proximate to the second end  58  of the center post  54 . The first bar  60  is shorter than and angled toward the second bar  61  such that the second end  64  of the first bar  60  intersects the second bar  61  at a point  68  proximate to but offset from the second end  65  of the second bar  61 . The second end  64  of the first bar  60  is rigidly connected to the second bar  61  at this intersection point  68 . Thus, the center post  54 , the first bar  60 , and the second bar  61  define the rigid frame portion  46  of the side frame  52 . Preferably, the rigid frame portion  46  with a first and second end is pivotally connected to the frame  18  by the pivoting frame portion  48  proximate to the center post  54 , as further described below. The rigid frame portion  46  is also configured to engage a forward lever  100  proximate to the second end  65  of the second bar  61 , as also further described below. It is contemplated that other numbers and configurations of bars may extend in the first direction from the center post  54 , or other central member, and may form other geometric shapes without deviating from the scope of the invention. 
         [0027]    A roller  80  is operatively connected between the second end  65  of the second bar  61  of each of the rigid frame portions  46 . The roller  80  includes, for example, a wheel  82  and an axle  83 . The axle  83  is rigidly mounted between the second bar  61  of each of the rigid frame portions  46 . An opening  81  extending through the center of the wheel  82  is configured to slide onto the axle  83 , rotatably mounting the wheel  82  to the axle  83 . 
         [0028]    The pivoting frame portion  48  of the side frame  52  includes a first member, e.g., a third bar  70  and a second member or bar, e.g., fourth bar  71 , extending generally in a second direction from the center post  54 , where the second direction is generally opposite the first direction in which the rigid frame portion  46  extends. Each of the third and fourth bars,  70  and  71 , has a first point or end,  72  and  73  respectively, and a second point or end,  74  and  75  respectively. Each of the second ends,  74  and  75 , is opposite from the respective first end,  72  and  73 . The first end  72  of the third bar  70  is pivotally mounted proximate to the first end  56  of the center post  54  at a first connection point. The first end  73  of the fourth bar  71  is pivotally mounted proximate to the second end  58  of the center post  54  at a second connection point. The second end  74  of the third bar  70  is pivotally mounted to the frame  18  at a first pivot rod  76 . The second end  75  of the fourth bar  71  is pivotally mounted to the frame  18  at a second pivot rod  78 . Optionally, each of the second ends,  74  and  75 , of the third and fourth bars,  70  and  71  respectively, may be connected to the frame  18  at separate pivot points without deviating from the scope of the invention. The third bar  70  is shorter than the fourth bar  71 , and the third and fourth bars,  70  and  71 , are angled toward each other such that they cross between the center post  54  and the frame  18 , forming an “X” as viewed from the side. 
         [0029]    Each mechanical multiplier  50  engages a corresponding forward lever  100 . The forward lever  100  has a first end  102  and a second end  104 . The first end  102  of the forward lever  100  is pivotally mounted at the second pivot rod  78 . The second end  104  of the forward lever  100  travels in an arcuate path from a first, retracted position to a second, extended position. The roller  80 , operatively connected between the second end  65  of the second bar  61  of each of the side frames  52 , engages a surface  101  of the lever, causing the forward lever  100  to move between the first and the second positions. 
         [0030]    A connection member  110  is mounted proximate to the second end  104  of the forward lever  100 . According to one embodiment of the invention, the connection member  110  is an eyehook. However, it is contemplated that the connection member  110  may be any suitable device to which a cable  112  may be connected. The cable  112  is operatively connected to the connection member  110  and extends toward the rear end  12  of the vehicle  10 . The cable  112  passes over a pulley  114  mounted on the frame  18  proximate the rear end  12  of the vehicle and is operatively connected to a connection member  116  mounted on a rear lever  120 . 
         [0031]    The rear lever  120  is pivoted about a drive shaft  126  by the cable  112  to rotate at least one wheel  20  of the vehicle  10 . The rear lever  120  includes a first end  122  and a second end  124 . The connection member  116  is mounted proximate to the first end  122 . The second end  124  is operatively connected to the drive shaft  126 . According to one embodiment of the invention, the second end  124  of the rear lever  120  is rigidly connecting to a ratcheting device such as an overriding clutch  130 . As shown in  FIG. 2 , the second end  124  of the rear lever  120  is operatively connected to the driving portion  132  of the overriding clutch  130 . The driven portion  134  of the overriding clutch  130  is mounted to the drive shaft  126 . The drive shaft  126  preferably includes one or more gears  140  mounted on the drive shaft  126 . The gears  140  on the drive shaft  126  may be coupled directly or indirectly, for example, via a chain or belt  144  to one or more gears  142  connected to a wheel  20 . The gears  142  connected to the wheel  20  may be mounted on a hub or an axle  146  for the wheel  20 . If multiple gears,  140  or  142 , are mounted on either the drive shaft  126  or the axle  146 , respectively, a selection device  150  may be included to engage the desired gear  140  on the drive shaft  126  to the desired gear  142  on the axle  146 . The selection device  150  may be, but is not limited to, a belt tensioner, a derailleur, or a clutch. 
         [0032]    In operation, an operator sits in the seat  14  and applies a force to at least one of the foot pedals  32 . The operator may apply the force to both foot pedals  32  in tandem or to one of the foot pedals  32  at a time in an alternating fashion. Each foot pedal  32  is mounted between the fourth bars  71  of each pivoting frame portion  48  of the side frame  52  proximate to the first end  73  of each of the fourth bars  71 . Because the second end  75  of each of the fourth bars  71  is pivotally connected to the second pivot rod  78 , the force applied to the foot pedal  32  causes the first end  73  of the fourth bar  71  of each side frame  52  of the mechanical multiplier  50  to pivot forward. The first end  73  of the fourth bar, being connected to the second end  58  of the center post  54 , causes the rigid frame portion  46  of the mechanical multiplier  50  to similarly rotate forward. 
         [0033]    As the rigid frame portion  46  of the mechanical multiplier  50  rotates forward, the third bar  70  also exerts a force on the rigid frame portion  46  of the mechanical multiplier  50 . The first end  72  of the third bar  70  is connected to the first end  56  of the center post  54 . Because the third bar  70  is shorter than the fourth bar  71  and because the second end  74  of the third bar is pivotally mounted to the frame  18  at the first pivot rod  76 , the third bar  70  exerts a rotational force on the rigid portion of the mechanical multiplier  50 , causing the center post  54  to rotate forward at a faster rate than the first end  73  of the fourth bar  71 . Thus, as the rigid frame portion  46  of the mechanical multiplier  50  is being moved forward by the fourth bar  71 , the third bar additionally causes the rigid frame portion  46  of the mechanical multiplier  50  to pivot about the connection between the first end  73  of the fourth bar and the second end  58  of the center post  54 . As a result, the end of the rigid frame portion  46  distal from the second pivot rod  78  travels a greater distance than the distance traveled by the foot pedal  32 . According to one embodiment of the invention, the distal end of each rigid frame portion  46  travels two to six times the distance and, preferably, at least four times the distance the foot pedal  32  travels. 
         [0034]    The roller  80 , mounted at the distal end of the mechanical multiplier  50 , transfers the force applied by the operator to the forward lever  100 . The roller  80  is mounted between the second ends  65  of the second bar  61  of each rigid frame portion  46 . A hole  81  in the center of each roller  80  slides over any suitable round member, allowing the roller  80  to rotate between the rigid frame portion  46 . As the mechanical multiplier rotates forward, the roller  80  engages a surface  101  proximate to the second end  104  of the forward lever  100 . The roller  80  causes the forward lever  100  to pivot about the first end  102  of the forward lever, rolling down the surface  101  as the rigid frame portion  46  of the mechanical multiplier  50  is both rotated forward by the fourth bar  71  and pivoted forward by the third bar  70 . Because the second end  104  of the forward lever  100  extends beyond the roller  80 , the second end  104  of the forward lever  100  will travel a still greater distance than the second end  65  of the second bar  61  of each rigid frame portion  46 . It is contemplated that the length of travel of the second end  65  of the forward lever  100  may be about  70  inches. 
         [0035]    As the forward lever  100  rotates forward, the cable  112  transfers the force from the forward lever  100  to a rear lever  120 . The cable  112  is connected to the connection member  110  mounted at the second end  104  of the forward lever  100 . Consequently, as the forward lever  100  is pivoted forward, the lever  100  pulls the cable  112  forward. The cable  112  is routed from the front end  11  to the rear end  12  of the vehicle over the pulley  114  mounted to the frame  18  at the rear end  12  of the vehicle. The opposite end of the cable  112  is affixed to the first end  122  of the rear lever  120 . Because the second end  124  of the rear lever  120  is connected to the overriding clutch  130 , as the cable  112  is pulled forward, it causes the rear lever  120  to pivot from a first position to a second position. 
         [0036]    The overriding clutch  130  has a driving portion  132  and a driven portion  134 . As the rear lever  120  is rotated from the first position to the second position, the rear lever  120  rotates the driving portion  132  of the overriding clutch  130  and the driving portion  132  engages the driven portion  134  using, for example, a ratchet or spring mechanism and transfers the force from the rear lever  120  to the drive shaft  126 . As the forward lever  100  returns to its original position, the cable is similarly returned to its original position, allowing the rear lever  120  to return to the first position. As the rear lever  120  moves from the second position back to the first position, the ratchet or spring mechanism disengages the driving portion  132  from the driven portion  134  and allows the drive shaft  126  to continue rotating in the forward direction. 
         [0037]    The gears  142  mounted to the drive shaft  126  transfer the energy from the drive shaft  126  to the axle  146  and the corresponding drive wheel  20  mounted to the axle  146 . According to one embodiment of the invention, a high gear  141  and a low gear  143  exist. The axle  146  includes a single gear  142  having a width sufficient to engage both the high gear  141  and the low gear  143 . Optionally, multiple gears  142  may be mounted on the axle  146 . It is contemplated that still other numbers and combinations of gears,  140  and  142 , may be coupled to the drive shaft  126  and the axle  146 , respectively, to facilitate transferring the energy from the drive shaft  126  to the axle  146  as the vehicle  10  is operating, for example, at different speeds or on varying grades. 
         [0038]    Each of the high and low gears,  141  and  143  respectively, includes a selection lever  152 . The desired selection lever  152  is raised up and placed on the lever holder  154  to select one of the gears,  141  or  143 . As the selection lever  152  is raised up and pulled forward, the gear selection device  150  engages one of the belts  144  between the gear  142  on the axle  146  and the corresponding high or low gear,  141  or  143 . Placing the selection lever  152  on the lever holder  154  maintains the required tension on the belt  144  without the operator having to continually hold the selection lever  152 . 
         [0039]    It is contemplated that one or more additional seats  14  may be added to the frame  18  to hold additional passengers and/or operators. For each additional seat  14 , corresponding mechanical multipliers  50 , forward and rear levers,  100  and  120 , cable  112 , and overriding clutches  130  may be mounted to allow multiple operators to each contribute to propelling the vehicle  10 . 
         [0040]    It should be understood that the invention is not limited in its application to the details of construction and arrangements of the components set forth herein. The invention is capable of other embodiments and of being practiced or carried out in various ways. Variations and modifications of the foregoing are within the scope of the present invention. It also being understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention.