Abstract:
A power assist apparatus which includes a battery pack that connects with a motor housing with the battery pack being removably mounted on the frame of the bicycle and the motor housing being mounting on a mounting plate which is carried by one of the support wheels of the bicycle. The power assist apparatus is designed to not only assist in the manual operation of the bicycle but also as a sole source of power for the bicycle. The mounting plate is to be affixed to the frame of the bicycle upon the desired location being selected for the mounting plate. The motor assembly operates a drive gear, pulley or sprocket which connects to a driven gear, pulley or sprocket which is mounted in conjunction with one of the support wheels of the bicycle. The motor housing may be disconnectable from the mounting plate as also the battery pack is capable of being disengaged from the frame of the bicycle permitting the bicycle to be used as a conventional bicycle without the power assist apparatus. The motor assembly is indexed to the axle of the support wheel maintaining accurate alignment in all operating conditions and upon repeated engagements and disengagements of the support wheel from the bicycle frame.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an electrically operated, by means of a battery, power assist apparatus for a bicycle and more particularly, to a new and novel construction of that power assist apparatus for a bicycle. 
     2. Description of the Prior Art 
     Electric powered bicycle have long been known. All electric powered bicycles incorporate an electric motor which is powered by a battery. One way the bicycle is powered is by a motor that operates through a drive wheel which frictionally engages with a support wheel of the bicycle. Movement of the drive wheel adds power to the manual movement of the bicycle or could be the only source of movement of the bicycle. Frictional engagement between the drive wheel and a support wheel is only one method. Others involve many configurations of direct drive involving shafts, chains, and gears but with the common feature of the driving motor being mounted on the bicycle frame in one position or another (e.g., near the pedaling sprocket, on one of the stays or on a rack above the rear support wheel). 
     The prior art direct drive power assist devices for a bicycle have generally required complex gearing arrangements. Upon removal of the wheel for maintenance, such as tire repair, precise reengagement is difficult leading to excessive wear and noise during operation. Also, complex gearing arrangements are difficult to maintain in precise alignment when the bicycle encounters road bumps and holes. Also, incorporation of prior art power assist apparatuses on bicycles has made it difficult to remove and replace the wheel(s) of the bicycle for tire repair and/or replacement. Additionally, if it is desired to use the bicycle as a normal bicycle and have the bicycle not carry the extra weight of a battery pack plus a motor assembly, the prior art direct drive power assist apparatuses for bicycles have not been designed to be readily removable from the bicycle to permit normal manual usage without the extra weight involved. 
     In prior art direct drive systems, the motor is mounted on the bicycle frame. Therefore, when the wheel is removed and replaced on the frame, such as required in order to change a tire or to do other types of maintenance, slight variations prevent precise realignment between the drive gear of the motor and the drive gear mounted on the wheel. These slight variations often result in excessive noise and wear. 
     SUMMARY OF THE INVENTION 
     The subject invention is a power assist apparatus for a bicycle which utilizes a direct drive mechanism between an electric motor and a drive gear, pulley or sprocket mounted on the hub of one of the wheels of the bicycle. It has been found to be most desirable to have the axis of the rotatable shaft of the motor parallel to the rotational shaft of a wheel for reasons of simplicity and smoothness of operation. A one-way clutching mechanism is to be mounted between the wheel and the motor. One or more batteries mounted within a battery pack are to be used to power the motor with this battery pack to be removably mounted on the frame of the bicycle. The motor is mounted within a motor housing with the motor housing being mounted within an enlarged hole formed within a mounting plate. The mounting plate is to be carried by a support wheel of the bicycle with either support wheel being satisfactory. This mounting plate is to be affixed by a bolt fastener (or pin) to the frame of the bicycle. This bolt or pin is to be easily removable. The mounting plate can be attached at any desired angular position on the support wheel but when selected is then fixed. The motor housing may be removably mounted on the mounting plate by a series of locking tabs being utilized to facilitate the engagement and disengagement of the motor housing to that mounting plate. 
     The primary objective of the present invention is to provide a vehicle of transportation for work and recreation that can be used by most people without adding to the smog caused by combustion engines, especially in urban areas. 
     Another primary objective of the present invention is to obtain a self-contained drive train support wheel configuration which, at all times, retains precision alignment between the gear attached to the drive motor and the driving gear attached to the axle of the bicycle. This is critical both for removal of the support wheel for repair and reengagement with bicycle frame to prevent any slight misalignments which cause excessive gear wear and noise. 
     A further objective of the present invention is to construct a power assist apparatus for a bicycle which is composed of few parts, is of lightweight construction, is efficient, is durable and requires a minimum of maintenance, and still can be manufactured economically. 
     Another objective of the present invention is to construct a smoothly operating, substantially vibration free, direct drive, power assist apparatus for a bicycle. 
     Another objective of the present invention is to construct a power assist apparatus for a bicycle which does not interfere with the maneuverability of the support wheel on which it is mounted in order to permit normal tire repair and replacement. 
     Another objective of the present invention is to construct a power assist apparatus which can be readily removed from the bicycle so that the bicycle can be manually operated in a normal manner when so desired without carrying the extra weight of the power assist apparatus. 
     Another objective of the present invention is to construct a power assist apparatus which is reengaged with precision indexed alignment between the gears when the support wheel is remounted on the bicycle. 
     A further objective of this invention is to obtain a practical direct drive gear system employing precision indexing and alignment which is in a self-contained bicycle rear wheel assembly that features: (1) precision alignment with repeated removal and reengagement of rear wheel for repair; (2) maintaining precision alignment in all rough environments; and (3) has fast conversion of non-electric to electric configuration (&lt;3 minutes) and back again with minimal weight penalty in normal operation. 
     A further objective of the present invention is that the bicycle can be used interchangeably with a regular support wheel or a “power wheel.” The power wheel contains the motor and the gear assembly whereas the regular wheel would be void of both the motor and the gear assembly. When the bicycle is used with the regular wheel, a common type of manually operated bicycle is obtained. When the bicycle is used with the power wheel, the power assist apparatus of the present invention is used to assist in powering of that bicycle. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of one type of bicycle upon which has been mounted the power assist apparatus of the present invention with it being understood that the power assist apparatus can be easily fitted to virtually any type of bicycle frame; 
     FIG. 2 is a rear view of the power assist apparatus which has been mounted on the rear wheel of the bicycle taken along line  2 — 2  of FIG. 1; 
     FIG. 3 is a top view of the power assist apparatus taken along line  3 — 3  of FIG. 2; 
     FIG. 4 is a side elevational view of the present invention showing the disconnection of the support wheel from the bicycle where the support wheel has mounted thereon a motor assembly; 
     FIG. 5 is a side elevational view of the power assist apparatus of the present invention where the motor housing of the motor assembly is disengageable from the mounting plate, whereas within FIGS. 1-4 the motor housing is fixed to the mounting plate; 
     FIG. 6 is an exploded side elevational view of the present invention showing the battery pack and the motor housing disengaged from the bicycle; 
     FIG. 7 is a cross-sectional view of the present invention through the motor housing mounting taken along line  7 — 7  of FIG. 5; 
     FIG. 8 is an enlarged front view of the present invention of a locking tab which is utilized to lock in position the motor housing in conjunction with the mounting plate; 
     FIG. 9 is a side elevational view of a second type of bicycle upon which has been mounted the power assist apparatus of the present invention which incorporates a belt drive arrangement; 
     FIG. 10 is a top view of the belt drive power assist apparatus taken along line  10 — 10  of FIG. 9; 
     FIG. 11 is a cross-sectional view showing in more detail the belt drive arrangement between the motor and the driven gear taken along line  11 — 11  of FIG. 10; and 
     FIG. 12 is a cross-sectional view of a chain and sprocket arrangement that could be used instead of the belt drive arrangement shown in FIG.  11 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     This invention is described in relation to a bicycle. However, it is understood that this invention could be used not only on a bicycle type vehicle that has two support wheels but also a bicycle type vehicle that has three or four support wheels. The word bicycle will be understood to include all such vehicles. The power assist apparatus could utilize an exterior gear connection, which is shown in the drawings, or could utilize an internal gearing arrangement mounted within the hub of the support wheel on which the motor of the power assist apparatus is mounted. Also, instead of gears, a chain or belt drive could be used. 
     Referring particularly to the drawings, there is shown a bicycle  10  having a front wheel  12  and a rear wheel  14 . The rear wheel  14  is rotatable solely within a plane of rotation. The front wheel  12  includes an axle  16  from which extends a plurality of wire spokes  18 . The wire spokes  18  are affixed to a tire rim  20  on which is mounted a rubber tire  22 . In a similar manner, the rear wheel  14  has an axle  24  which is mounted within an axle sleeve  26 . Affixed to each end of the axle sleeve  26  is a mounting disc  28  with it being understood that there are two in number of the mounting discs  28 . The inner end of wire spokes  30  are attached to the mounting discs  28  with the outer end of the wire spokes  30  being fixedly secured within a tire rim  32 . Mounted on the tire rim  32  is a rubber tire  34 . Mounted on one end of the axle  24  is a derailleur  36 . The derailleur  36  forms no specific part of this invention as it is deemed to be conventional. The derailleur  36  connects to a drive chain  38 . The drive chain  38  connects the derailleur  36  to a chain wheel  40 . The chain wheel  40  is rotatable mounted by axle  42  to the frame  44  on the bicycle. The frame  44  is composed of chain stays  46  and  48 , seat tube  50 , main frame member  54 , seat stay  56  and front fork  58 . The front fork  58  is used to mount the front wheel  12  onto the main frame member  54 . The bicycle seat  60  is mounted on the seat tube  50  with the seat stay  56  being connected between the seat tube  50  and the bracket  62  which mounts the main frame member  54  to the rear axle  24 . The chain stay  46  connects between the sleeve (not shown) through which is mounted the axle  42  to the bracket  62 . Mounted in conjunction with the axle  42  is a pair of cranks  64  which extends in directions opposite to the axle  42 . Mounted on the outer end of each crank  64  is a pedal  66 . Normal conventional movement of the bicycle  10  is accomplished by manually rotating the cranks  64  about the axle  42  which causes rotation of the derailleur  36  through the drive chain  38 . Rotation of the derailleur  36  will result in rotation of the rear wheel  14  which results in movement of the bicycle  10  on the supporting surface  68 . 
     The front fork  58  is mounted on a head tube  70  which is part of the frame  44 . Also mounted on the head tube  70  is a handlebar  72 . Mounted on the handlebar  72  is an electrical control unit  78 . The electrical control unit  78  is to be operated by the human riding the bicycle  10 . The electrical control unit  78  is to be mounted on the handlebar  72 . 
     An electrical wire  80  extends from the electrical control unit  78  to a junction connector  82 . A throttle wire  84  also extends from throttle  86  to the junction connector  82 . The throttle  86  is to be manually moved to various positions to increase or decrease the speed of the power assist apparatus of this invention which is to be described further on in this specification. Also connected with the junction connector  82  is a battery wire  88 . The battery wire  88  connects with battery  90  which is mounted within a battery case  92 . Battery  90  may comprise a plurality of separate batteries connected electrically in a series. The battery case  92  is to be removably mounted by means of straps  94  and  96  onto straps  98  and  100  which are fixedly secured to the seat tube  50 . Any other type of quick disconnect system could be used for the battery case  92 . It is to be understood that the battery case  92  can be removed from the seat tube  50  by disconnecting the straps  94  and  96  from the straps  98  and  100  for the purpose of lightening the weight of the bicycle  10  when it is desired to use the bicycle  10  as a conventional bicycle and not utilize the power assist apparatus of this invention which will be described further on in this specification. 
     Also connected with the junction connector  82  is a motor wire  102 . The motor wire  102  supplies electrical power from the battery  90  to the motor (not shown) mounted within motor housing  104 . The motor housing  104  in FIGS. 1-4 of the drawings is fixedly mounted onto a mounting plate  106 . The motor causes rotation of a drive pinion gear  108 . The drive pinion gear  108  is to be in continuous contact with driven gear  110 . The driven gear  110  is to be rotated in a rotational plane which is parallel to the plane of rotation of the rear wheel  14 . The driven gear  110  is mounted by a clutch  112  to a clutch plate  114 . Clutch  112  is concentric with the rear wheel  14 . The clutch plate  114  is fixedly mounted onto the axle  24 . The clutch  112  is to connect together in rotative movement the driven gear  110  and the rear wheel  114  when the driven gear  110  is being rotated at the same speed (rpm) as the rear wheel  14 . However, when the rotation of the rear wheel  14  is at a greater rpm than the driven gear  110 , the clutch  112  will permit the rear wheel  14  to rotate freely relative to the driven gear  110 . This type of clutch  112  is desired so that the wheel  114  can freely rotate as when the bicycle goes down hills and it is not necessary to have the motor contained within the motor housing  104  engaged for operation. It is important to note that the axis of rotation of drive pinion gear  108  is always parallel to the axis of rotation of axle  24 . This indexing of the motor to the axle  24  is absolutely necessary to have the drive arrangement be as noise free as possible and as wear free as possible. 
     The mounting plate  106  is mounted on the axle  24 . There is a bearing (not shown) between the axle  24  and the mounting plate  106  which permits the axle  24  to rotate freely relative to the mounting plate  106 . It is to be noted that initially during mounting of the motor housing  104  on the axle  24  that any desired angular position of the mounting plate  106  could be selected relative to the axle  24 . This is desired so that the mounting plate  106  can be selected for the particular bicycle  10  so as to not interfere with any other structural component of the bicycle  10 . Once the particular desired angular selection is made, it is important that a fastener  116  such as a bolt or pin be mounted between a portion of the frame  44 , such as chain stay  46 , and hole  118  formed within the mounting plate  106 . This fastener  116  now fixed in position the mounting plate  106  relative to the frame  44  of the bicycle  10 . This fastener  116  permits the transfer of torque from the motor contained in the motor housing  104  to the rear wheel  14  and is capable of producing rotational movement of the rear wheel  14 . The fastener  116  is to be removable. 
     An important consideration of the present invention, which is clearly shown in FIG. 4, is that when the fastener  116  is removed and the wire  102  is disengaged from the junction connector  82 , the entire rear wheel  14  can then be separated from bracket  62  which will then permit maintenance to be performed on the rear wheel  14  such as replacement of the rubber tire  34 . It is to be noted that the junction box  82 , shown mounted on the seat tube  50 , could be mounted at any desired location with another preferable location possibly being on the outer surface of the battery case  92 . 
     The size of the motor (not shown) located within the motor housing  104  will typically be about three and one-half inches in diameter with a length of between two to five inches depending on the power desired. The driven gear  110  till typically have a diameter of about seven inches. The drive pinion gear  108  has a diameter of about three-quarters of an inch for a gear ratio of 9.3 to 1. If the rear wheel  14  is twenty-six inches in diameter, the revolutions per minute (rpm) of the motor would be about eighteen hundred at fifteen miles per hour. The motor is to be designed to achieve optimum efficiency in the twelve to eighteen hundred rpm range. It is to be understood that the power assist apparatus is independent of the derailleur  36 . 
     Referring particularly to FIGS. 5-8 of the drawings, there is shown a modified form of mounting for the motor housing  104 . Instead of the motor housing  104  being fixedly mounted onto the mounting plate, a modified form of mounting plate  120  is utilized which includes enlarged hole  122 . The housing  104  includes annular extension  124 . The annular extension  124  is to fit in a close fitting relationship within the enlarged hole  122 . Extending outward from the annular extension  124  in between the outer edge of the annular extension  124  and the motor housing  104  is an annular ridge  126 . The annular ridge  126  is to abut against the mounting plate  120 . Mounted on the mounting plate  120  are three in number of locking tabs  128 . The locking tabs  128  are angularly spaced about the enlarged hole  122 . Each locking tab is mounted by means of a bolt fastener  130 . The bolt fastener  130  can be loosened and the locking tab moved from an engaged position with the annular ridge  126 , as shown in FIGS. 5 and 7 and also in the solid line position shown in FIG. 8, to a disengaged position which is shown in dotted lines in FIG.  8 . The disengaged position spaces the locking tab  128  from the annular ridge  126 . It is to be understood that by tightening the bolt fasteners  130  the locking tabs  128  can securely to clamp the annular ridge  126  to the mounting plate  120 . Loosening of the bolt fasteners  130  will permit the locking tabs  128  to be pivoted to a displaced position from the annular ridge  126  which will then permit the motor housing  104  to be removed from the enlarged hole  122 . At that particular time, the wire  104  disengages from the junction connector  82 . The user will then be able to quickly and conveniently disengage the motor and the motor housing  104  and the battery  90  and the battery case  92  from the bicycle  10  which will then permit the bicycle  10  to be used as a conventional bicycle not bearing the extra weight of the battery  90  and battery case  92  and the motor and motor housing  104 . Each time when the motor housing  104  is removed from the mounting plate  120  and then replaced in conjunction with the mounting plate  120 , the rotational axis of the drive pinion gear  108  will again be located precisely parallel to the rotational axis of the axle  24 . This is important to always have the drive pinion gear  108  indexed in this position relative to the axle  24 . In other words, disengaging of the motor housing  104  from the mounting plate  120  and then reengaging of same to the mounting plate  120  insures that this indexing relationship is reestablished with precision. 
     Referring particularly to FIGS. 9 and 11, there is shown a second type of bicycle  132  upon which has been mounted the power assist apparatus of this invention. The power assist apparatus includes the same motor housing  104  mounted by a plurality of locking tabs  128  on a mounting plate  120 . The mounting plate  120  is pivotally mounted on the axle  134  of the rear wheel  136  of the bicycle  132 . The bicycle  132  includes a derailleur  138  which is mounted on the rear wheel  136 . The derailleur  138  is to connect with the chain  140  which in turn connects with the chain wheel  142 . The chain wheel  142  is mounted on the frame  144  of the bicycle  132 . Connecting with the chain wheel  142  are cranks  146  which are to be rotated manually by means of pedals  148 . It is to be noted that the bicycle  132  is what is termed a conventional “mountain bike.” The bicycle  132  is of different configuration than the bicycle  10 . 
     The motor mounted within the motor housing  104  is electrically operated by means of a battery (not shown) mounted within the battery case  150 . The battery case  150  is mounted by straps  152  and  154  on the seat tube  156  of the bicycle frame  144 . 
     The mounting plate  120  is fixedly secured to the frame  144  by means of a bolt or pin fastener  158 . Any desired position of the motor housing  104  can be obtained as long as the motor housing  104  does not interfere with any portion of the frame  144 . Instead of the driven gear  110  there is substituted a driven pulley  160  mounted about a clutch (not shown). This clutch is mounted on clutch plate  162 . The clutch plate  162  is fixedly mounted onto the axle  134 . The clutch plate  162  connects together in rotative movement the driven pulley  160  and the rear wheel  136  when the driven pulley  160  is being rotated at the same speed (rpm) as the rear wheel  136 . However, as was previously discussed, when the rotation of the rear wheel  136  is at a greater rpm than the driven pulley  160 , the clutch will permit the rear wheel  136  to rotate freely relative to the driven pulley  160 . 
     Extending from the motor mounted within the motor housing  104  is a drive pulley  164 . The drive pulley  164  is substituted for the drive pinion gear  108 . It is to be noted that the drive pulley  164  is not directly engaged with the driven pulley  160  with the drive pulley  164  being spaced apart from the driven pulley  160 . However, the rotative torque from the motor contained within the motor housing  104  is transmitted to the driven pulley  160  by means of a drive belt  166  which connects between the drive pulley  164  and the driven pulley  160 . 
     It is again to be emphasized that even when the rear wheel  136  is removed from the bicycle  132 , and upon replacement of the rear wheel  136  on the bicycle  132 , the precise identical driving arrangement is maintained between the motor mounted within the motor housing  104  and the wheel axle  134 . This indexing of the motor to the axle  134  is achieved by the rotational axis of the drive pulley gear  164  being located precisely parallel to the rotational axis of the axle  134 . However, additionally even if the motor housing  104  is removed from the mounting plate  120  which would disengage the drive pulley  164  from the belt  166 , upon reengagement of the motor housing  104  with the mounting plate  120 , the drive pulley  164 , when reengaged with the belt  166 , will again locate the rotational axis of the drive pulley  164  precisely parallel to the axle  134 . 
     Referring particularly to FIG. 12, there is shown a driven sprocket  168  and a drive sprocket  170 . A chain  172  could be used to connect between the drive sprocket  170  and the driven sprocket  168 . The driven sprocket  168  would be used instead of the driven pulley  160  or the driven gear  110 . The drive sprocket  170 , which connects to the motor (not shown), is to be substituted for the drive pulley  164  or the drive pinion gear  108 .