Abstract:
Improved mechanical structure for increased efficiency in the transfer of the peddling force applied to a pedal crank assembly to the rear wheel of a bicycle is disclosed. This structure increases efficiency by decreasing the loss of exerted energy when peddling at dead spots, which dead spots are the common terminology used to refer to when the legs are either at down-stroke and up-stroke positions.

Description:
RELATED APPLICATION 
     Provisional Patent No. 60/253,093 dated Nov. 28, 2000 
    
    
     Not sponsored by Federal research and development 
     BACKGROUND OF THE INVENTION 
     This invention relates to a means for increased efficiency in peddling bicycles. Depending on the position of a cyclist&#39;s foot, different fractions of the force exercised are conveyed to automation. It is generally accepted that peddling is least efficient at either the up-stroke or the down-stroke positions. This is due to the fact that the human leg&#39;s ability to push downward is higher than its ability to apply a force in a horizontal direction. The up-stroke and the down-stroke positions of peddling are commonly referred to as dead spots. Stop and start cranking at the dead spots will result in lower speed capability due to interruption and discontinuity. 
     Previous efforts to solve this inefficiency include a design by Jaimes under U.S. Pat. No. 5,911,792, issued Jun. 15, 1999 that presents an orifice located at the middle part of the cranks vertex to resolve the problem; by Nagano, U.S. Pat. No. 5,257,562, issued November 1993, disclosing a crank bar assembly wherein the position of the connection of the pedals to the crank bars can be shifted to-and-fro to reduce inefficiency. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Six drawings presented show side elevational views of different drive trains for connecting the gears driven by the pedals and those driving the driven wheels, using a chain or a belt. Also two additional drawings are presented illustrating the increased arc through which the pedals may be driven when driven rearwardly. 
     FIG. 1 shows a design in which a closed loop drive chain  168  is meshed with and drivingly connects a pedal or drive wheel gear  156  with an auxiliary gear  158 , each journalled from a bicycle frame  150  and with the chain  168  also meshed with a driven wheel gear  162  journalled from the frame  150 , the drive wheel gear  156  being driven in a direction opposite to the direction of rotation of the driven wheel gear  162  by a journalled pedal crank assembly  152 . 
     FIG. 2 shows a design in which a closed loop drive chain  126  is meshed with a driven wheel gear  122  and with an auxiliary gear wheel  118  journalled from a bicycle frame  110  and with a journalled drive or pedal gear wheel  116  also meshed with chain  126 , the drive gear wheel  116  and drive wheel  122  rotating in opposite directions. 
     FIG. 3 shows a design with a closed loop drive chain  58  meshed with a journalled drive or pedal wheel gear  56  and an oppositely rotating, journalled driven wheel gear  60 , the two reaches of the chain  58  being crossed. 
     FIG. 4 shows a design using an auxiliary gear  16  journalled from a bicycle frame  10  and meshed with a drive or pedal gear  20  also journalled from frame  10 . A drive gear  22  is fixed to the gear  16  and rotates therewith. A drive chain  24  orbits in a direction opposite to the direction of rotation of the pedal gear  20  and orbits and drives an associated driven wheel (not shown) similar to driven wheel  122 . 
     FIG. 5 shows a design using a driven wheel gear  220  meshed with an auxiliary gear  216  journalled from a bicycle frame  214  and including a second auxiliary gear  226  fastened to auxiliary gear  216 . A closed loop drive chain  224  is trained about gear  226  and drives an associated driven wheel  212 . 
     FIG. 6 shows a design in which two auxiliary gears  258  and  262  are journalled from a bicycle frame  250  and meshed together for opposite rotation. Also shown are two closed loop chains  266  and  268 . The chain  266  is meshed with auxiliary gear  258  and a drive or pedal wheel gear  254  and the chain  268  is meshed with auxiliary gear  262  and driven wheel gear  270  to rotate driven wheel gear  270  in a direction opposite to the direction of rotation of the pedal or drive wheel gear  254 . 
     FIG. 7 illustrates the uppermost or down-stroke position of the peddling foot; and 
     FIG. 8 illustrates a position of the peddling foot slightly past the lowermost position of the peddling foot when peddling in a counter-clockwise direction. 
    
    
     SUMMARY OF THE INVENTION 
     The purpose of the invention claimed herein is to minimize the negative influence of dead spots in cycling action. 
     When using a conventional bicycle and the peddling foot is at the beginning of the down-stroke position (FIG.  7 ), the thigh portion of the leg is generally at a horizontal position while the calf portion of the leg is inclined backward in a generally 45° direction. At this cramped leg position, the leg&#39;s ability to apply a force in the forward direction is severely hampered. However, effective rearward application of the force in a general 45° rearward direction is efficient and productive. Similarly, when using a conventional bicycle and the peddling foot is at the beginning of the up-stroke position, the leg&#39;s ability to exert a force in the rearward direction past bottom dead center is severely hampered. 
     However, subject to sufficient upward and rearward displacement of the position of the seat relative to the pedal crank assembly along a line passing through the axis of rotation of the pedal crank assembly and inclined generally 30 degrees relative to the vertical, forward application of force well past this dead spot is productive. Thus, it becomes evident that rearward peddling for forward locomotion will be effective in reducing the negative affects of dead spots, subject to sufficient rearward displacement of positioning of the bicycle seat from a vertical line passing through the axis of the pedal crank assembly. Driving action is interrupted in conventional bicycles when action is switched from one leg to the other since each leg acts through an angle of less than 180°. Overlapping and uninterrupted cycling action is provided by the bicycle disclosed and claimed herein. The bicycle of the instant invention includes means to peddle backward for forward locomotion to eliminate the influence of dead spots in the cycling action. The innovation claimed herein provides numerous improvements compared with other resolutions of the dead spot problem, including: 
     1. Reduced cost of production; 
     2. Simplicity of the design with an operation requiring fewer parts; 
     3. Less maintenance; 
     4. Lighter weight; 
     5. Ease of operation; and 
     6. Ease of alteration of existing bicycles. 
     It is noteworthy that a second advantage of the design claimed is that rearward displacement of the bicycle seat will result in a shift of peddling action forward of the hip position. As a result, the need for slim bicycle seats is eliminated and the use of wide and comfortable seats for the overweight and elderly, as well as for prolonged users is made feasible. 
     The principle objective of this invention is to provide a light-weight bicycle that can be comfortably ridden and driven by the operator thereof. 
     Another objective of this invention is to provide a bicycle in accordance with the preceding objectives which will conform to conventional forms of manufacture, be of simple construction, and easy to operate, so as to provide a device that will be economically feasible, long lasting, and relatively trouble-free in operation. 
     These, together with other objectives and advantages that will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed. References to accompanying drawings form a part thereof, with like numerals referring to like parts throughout. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now more specifically to the drawings, FIG. 1 shows a side elevational view of a first form of bicycle contructed in accordance with the present invention. Numeral  150  shows a frame of a bicycle  151  with a drive or pedal wheel gear  156  supported from a pedal crank assembly  152  journalled from the frame  150  at  154 . Numeral  162  refers to a rear driven wheel gear journalled from frame  150  at  166  and including a one-way clutch structure (not shown) for driving, in the forward direction, a driven wheel  164  also journalled from frame  150  at  166 . An auxiliary wheel  158  is included and journalled from frame  150  at  160 . A closed loop chain  168  is meshed with drive or pedal wheel gear  156  and with auxiliary wheel  158 . The driven wheel gear  162  is also meshed with chain  168  as shown such that peddling in rearward direction (counter clockwise) drives the bicycle  151  in the forward direction. 
     Attention is now directed to the second form of the invention. In FIG. 2 a pedal or drive wheel gear  116  is journalled from a bicycle frame  110  at  114  and a driven wheel gear  122  is journalled from frame  110  at  124 . Driven wheel gear  122  includes a one-way clutch structure (not shown). An auxiliary wheel  118  is journalled from frame  110  at  120 . A closed loop chain  126  is meshed with auxiliary wheel  118  and with driven wheel gear  122 . The pedal or drive wheel gear  116  is meshed with chain  126  as shown such that peddling rearward (counter clockwise) drives frame  110  in the forward direction, to the right. 
     Attention is now directed to the third form of the invention. FIG. 3 shows a side elevational view of a bicycle frame  50  with a drive wheel assembly  70  including a pedal or drive wheel gear  56  and a pedal crank assembly  52  journalled from frame  50  at  54  and with a driven wheel gear  60  (including a one-way clutch structure and a driven wheel gear  66  rotatably attached to frame  50  at  62 . A closed loop chain  58  is meshed with the pedal or drive wheel gear  56  in a direction opposite of the direction it is meshed with the driven wheel gear  66  such that rotation of the pedal crank assembly  52  in an anti-clockwise direction drives frame  50  in a forward direction (to the right). For best results the gears may either be tilted, or guiding wheels or spacers (not shown) need be provided to keep the chains in different tracts at their junction. 
     Attention is now directed to the fourth form of the invention. FIG. 4 shows the side elevational view of a bicycle frame  10  with pedal crank assembly  12  and pedal or drive wheel gear  20  fastened together and journalled from frame  10  at  14 . Two auxiliary gears  16  and  22  are coupled with each other and journalled from frame  10  at  18  with gear  16  meshed with pedal wheel gear  20 . A closed loop chain  24  is meshed with a driven wheel gear (not shown) and with auxiliary gear  22  as shown such that rearward peddling (counter clockwise) drives the frame  10  in a forward direction (to the right). It is readily visible that the two auxiliary gears  16  and  22  could be of the same diameter in which case said two gears can be combined into one gear. 
     Attention is now directed to the fifth form of the invention. FIG. 5 shows a side elevational view of a bicycle frame  214  with a driven wheel gear  220  journalled from a bicycle frame  214  at  222  and meshed with an auxiliary gear  216  coupled to a second auxiliary gear  226  and journalled from frame  214  at  218 . A driven wheel  212  is journalled from the bicycle frame  214  at  222 . 
     A closed loop chain  224  is meshed with auxiliary gear  226  such that peddling rearward (anti-clockwise) on an associated pedal crank assembly (not shown) about which the chain  224  is also meshed drives frame  214  in a forward direction (to the left). It is readily visible that the two auxiliary gears  216  and  226  can be of the same diameter and that the two auxiliary gears  216  and  226  can be combined into one gear. 
     Attention is now given to the sixth form of the invention. FIG. 6 shows the side elevational view of a bicycle frame  250  with drive wheel  274  and adjoined driven wheel gear  270  journalled from frame  250  at  272  and with a crank assembly  252  and adjoined pedal or drive wheel gear  254  journalled from frame  250  at  256 . Included are two intermeshed auxiliary sprocket wheels  258  and  262  journalled from frame  250  at  264  and  260  respectively. Two closed loop chains  266  and  268  are employed. The chain  266  is meshed with the pedal or drive wheel gear  254  and with the sprocket wheel  258 . The chain  268  is meshed with the driven wheel gear  270  and the sprocket wheel  262 . The sprocket wheels  258  and  262  include meshed gears (not shown) such that the sprocket wheels  258  and  262  rotate in opposite directions. Therefore, peddling backwards (anti-clockwise) drives the frame  250  in a forward direction (to the right). 
     FIG. ( 1 ) is further employed to illustrate attachment of a separate and supplementary assembly  200  to an existing bicycle  150  as a means for connecting said bicycle pedal gear  156  to the driven wheel gear  162 . The assembly  200  includes a bracket  169  to be fastened to the bicycle frame at the pivotal axis  166  of the drive wheel  164 . Included is a supplementary gear  158  journalled to bracket  169  at  160 . Included is also a closed loop drive chain  168  to be meshed with supplementary gear  160  and with the existing bicycle pedal gear  156  while being engaged with the existing bicycle drive wheel gear  162  in such manner that peddling in rearward direction (counter clockwise) drives the bicycle in the forward direction (to the right). 
     Referring to FIGS. 7 and 8, it will be noted that the seat S is positioned appreciably above the journal axis of the drive or pedal wheel gear  156 . Further, the seat S is positioned appreciably rearward of a vertical line passing through the pedal wheel gear axis. The arrangement shown insures that a user of the bicycle is seated in a substantially upright position and yet physically able to “pump” the pedal crank assembly  152  with each leg through an arc substantially greater than 180° (at least 210+°). The active force duration in each cycle depends on the bicycle and the physical measurements of the rider. For the seat position at angles of 30° rearward of the line of gravity (FIGS. 7 and 8) the peddling action begins shortly before the down stroke position and continues about 30° beyond the lower pedal position (FIG.  8 ). The result is an active force capability of about 210+° per cycle. 
     It is now pointed out that the bicycle of the instant invention is designed to be ridden in a substantially upright position and with the seat positioned appreciably above and to the rear of the axis of rotation of the pedal crank or crank bar assembly  152 . This not only keeps the head of the rider at a high elevation for safety reasons, but also increases the effectiveness of the reversing pedal drive train. Further, a substantially conventional bicycle frame may be modified in a relatively easy manner to be in accordance with the present invention. 
     It is believed evident that, as an alternative means, either chain may be replaced by a drive belt. Further, it may be readily seen from the drawings that the drive mechanisms of the bicycles shown are very reliable and require very little maintenance. Further, these drive mechanisms are relatively free of operating resistance and may be constructed of relatively light-weight materials. Therefore, the bicycles claimed may be economically produced and are operable in a relatively effortless manner.