Abstract:
An electric motor assembly to power a wheeled vehicle is disclosed comprising a support bracket having a horizontal mounting plate and a vertical mounting plate, each of which has edges and a central notch in one edge. An electric motor with an elongated spindle is adjustably secured to the bracket, and a battery capable of powering the motor is also mounted on the bracket. The notch of the horizontal plate receives a steering column of the vehicle in clamped engagement. The notch on the vertical mounting plate is sized to straddle and clear a front wheel of the scooter.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the benefit of U.S. Provisional Application Serial No. 60/258,002 filed Dec. 21, 2000. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    Much effort has gone into developing motorized scooters, bicycles, go-carts, personal-mobility devices for handicapped persons, and other traditionally user-powered vehicles. Such powered vehicles often suffer from disadvantages such as noise and pollution (e.g., gasoline powered engines), extra weight (e.g., heavy batteries and motor components), and awkward center-of-balance issues when weight is not well distributed on the frame of the vehicle. Furthermore, a vehicle fitted with such a motor often is very difficult to manage when the motor is not in use, and it may be difficult or impossible to remove the motor from the vehicle. A need exists for a clean, quiet, powerful and lightweight motor source that is compact and easy to install and remove if desired.  
         SUMMARY OF THE INVENTION  
         [0003]    The motor assembly of the invention provides a lightweight and powerful electric motor and mounting assembly that is compact and can be permanently mounted or easily installed and removed.  
           [0004]    The electric motor assembly of the invention comprises a support structure that has a horizontal mounting surface and a vertical mounting surface, each of the horizontal and vertical mounting surfaces having edges and a notch in one edge. The horizontal and vertical mounting surfaces need not be strictly horizontal and vertical as installed or with respect to each other; rather, it is important only that enough structure exists to mount the motor, the batteries, and the entire assembly onto the vehicle as described herein. Thus, “edge” of the mounting surfaces as used herein is intended to mean a side of the surface, whether that side is straight, curved, or uneven in any way.  
           [0005]    The assembly also includes an electric motor with an elongated spindle extending from the armature. The motor is capable of turning the elongated spindle when supplied with power. The motor is powered by a battery which can be connected to the motor, and the support structure is adapted to have both the battery and the electric motor mounted on it. The notch on the vertical mounting surface is sized to straddle the edge of a driven wheel of the vehicle, and the notch on the horizontal mounting surface is sized to fit onto a selected mounting point. Advantages of this mounting assembly include the need for only simple hand tools to affix the assembly to the vehicle without the need for additional brackets or supports; a compact design with the motor and battery located on a single support; and a safety feature that the mounting assembly limits rotational freedom of the wheel. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in conjunction with the accompanying figures wherein:  
         [0007]    [0007]FIG. 1 is a perspective view of a scooter embodying the invention;  
         [0008]    [0008]FIG. 2 is a perspective view similar to FIG. 1, but with a decorative and protective cover removed from the front of the scooter;  
         [0009]    [0009]FIG. 3 is an exploded perspective view of the scooter front wheel and a support structure of the invention; and  
         [0010]    [0010]FIG. 4 is a side view of a front wheel assembly, and showing the support structure in section. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]    The vehicle motor assembly of the invention is designed to be front-wheel mounted on a vehicle, and easily installed and removed during manufacture and after-market. Alternatively, it can be permanently installed on the vehicle. The motor assembly has an electric motor with a drive shaft spindle that frictionally engages and drives the wheel when the motor is activated, and that spins freely with minimal friction when the motor is off. The motor is held on a mounting and support structure that adjustably places the drive shaft spindle in contact with the front wheel and that also holds the batteries. These features provide a simple fork mounting system that requires only basic hand tools for installation and removal, needs no extra supports or brackets, and allows the vehicle to be operated with the motor on, or by the user&#39;s physical energy in the normal way without increased resistance and very little added weight when the motor is turned off. The mounting system and motor of the invention can be used on any wheeled vehicle, such as a bicycle, tricycle, push scooter, go-cart, etc. A preferred embodiment is a mounting assembly and motor for a push scooter, and this embodiment will be described herein, without limiting the scope of the invention.  
         [0012]    [0012]FIGS. 1 and 2 show a conventional push scooter  10  having an elongated foot-supporting platform  11  with a rear end which rotatably supports a rear wheel  12 . A fender  13  is pivotably mounted on the platform over the rear wheel, and can be depressed by the rider&#39;s foot to act as a brake. A pair of part-circle guide plates  15  are rigidly secured to and extend upwardly from a front end of the platform, and a support member  16  is positioned between and extends upwardly and forwardly from the guide plates. A lower end of support member  16  (FIG. 4) is pivotable about a pin  17  extending between the guide plates. The support member is secured in a riding position as shown in the drawings by a clamp  18 .  
         [0013]    A tubular support  20  (FIGS. 2 and 4) is rigidly secured at the upper forward end of support member  16 , and a steering column  21  is supported by and rotatably journaled through support  20 . A steering handlebar  22  is secured at the top of the steering column, and a front wheel  23  of the scooter is rotatably supported on a fork  24  (FIGS. 3 and 4) secured at the bottom of the column. Releasing clamp  18  and actuating a release button  25  (FIG. 4) enables support member  16  and the steering column to be hinged downwardly about pivot pin  17  against platform  11  for compact storage or during carrying of the scooter. The components thus far described are conventional, and are parts which typify commercially available push scooters.  
         [0014]    A drive motor assembly  27 , best seen in FIGS. 2 and 4, is mounted at the lower front end of scooter  10  adjacent front wheel  23 . The assembly includes a rigid support bracket  28  of generally T-shaped cross section. As best seen in FIG. 3, bracket  28  has an upper mounting plate  29  with a central rearwardly extending notch  30  which is preferably semicircular. Extending from the underside of plate  29  in lower mounting plate  31  which has a central and upwardly extending notch  32  which preferably has a semicircular base  33 . Notch  30  is dimensioned to make a snug fit around the lower end of steering column  21 , and notch  32  is dimensioned to provide a clearance opening for front wheel  23  when assembly  27  is installed.  
         [0015]    Assembly  27  further includes a generally cylindrical electric motor  35  which is secured by a clamping strap  36  beneath a first end of upper mounting plate  290  and in front of lower mounting plate  31 . The motor seats in a right-angle saddle  37 , the vertical position of which is adjustable by a pair of adjusting screws  38  threaded through the upper plate to bear on the top of the saddle (FIG. 4). Alternative means for securing the motor and bracket can of course be used.  
         [0016]    An electric battery  40  is mounted on a second end of upper mounting  29 , and is held by a clamp  41 . The battery is connected to the motor through a handlebar-mounted switch  42  by a cable  43 . The motor has a drive shaft or spindle  44  extending therefrom. When used on a scooter, the spindle is preferably aluminum which has good heat-dissipating properties, and is also preferably smooth for gripping, but non-abrasive contact with a solid urethane wheel with which scooters are typically equipped.  
         [0017]    Assembly  29  is easily installed on the scooter by fitting upper plate  29  of the support bracket against steering column  21 , with the steering column received in notch  30 . Front wheel  23  makes a clearance fit within notch  32  of the lower mounting plate. The assembly is then clamped in place by a pair of threaded bolts  46  (FIGS. 3 and 4) extending through clearance openings in lower plate  31  and a clamp plate  47 , and tightened into nuts  48  to secure the clamp plate against the front of fork  24 . Adjusting screws  38  are advanced to place motor spindle  44  in frictional engagement with the perimeter of front wheel  23 . If the scooter is being pushed by the rider without motor assistance, the adjusting screws can be retracted, or the motor spindle can rotate freely when driven by the front wheel. Assembly is completed by clamping an optional decorative and protective cover  50  secured to the front of the scooter over assembly  27 .  
         [0018]    Motor  35  can be of any electric type that has a high efficiency, preferably over 50%, more preferably over 65%, and most preferably 80% or above. Particularly preferred motors are d-c motors using 12-24 volt nickel-cadmium batteries which are rechargeable, reduced in size, and have greater capacity than other batteries. Electric motors of this type generally have a ferrite core or high performance cobalt magnets, and operate at high RPMs. Suitable electric motors can be obtained, for example, from AstroFlight, Inc. (Marina Del Rey, Calif.).  
         [0019]    The torque or gear ratio of the drive system is determined by the diameter of the motor spindle. Preferably, the spindle is selected so that the motor has a relatively low gear ratio. Preferably, the spindle size is between about {fraction (3/16)} of an inch to ¾ of an inch, more preferably between about ⅜ to ½ of an inch. A spindle of about ½ inch diameter is suitable for light loads, such as a scooter used by children, and will have a longer ride time on a single battery. However, for heavier loads such as an adult, a spindle of about ⅜-inch diameter gives sufficient torque and battery longevity. Motors with these spindles are generally about 80-90% efficient, compared to the roughly 40-42% efficiency of a standard fan motor such as is used on many motorized scooters and bicycles.  
         [0020]    The preferred motor for use in the invention is usually about ⅛ to 1 horsepower, depending on the size of the vehicle and occupant to be moved, but can be of any appropriate power. In the scooter embodiment depicted herein, the motor is ⅛ hp and can power the scooter and an adult rider. An internal or external fan for the motor can optionally be used to cool the motor drive for improved efficiency.  
         [0021]    Power for these motors is usually provided by a series of nickel-cadmium cells made up into packs. Six and seven cell packs are most common, but larger cobalt motors may require up to 28 or more cells. These batteries are light and can be recharged quickly in about 15 to 60 minutes. Alternatively, 12-24 volt lead-acid and sealed batteries can be used, or titanium batteries for longer run and more power. These are also rechargeable (overnight) and with the higher capacity will give much longer run times.  
         [0022]    Battery  40  is mounted on the support bracket to be easily accessible for rapid battery removal and replacement. Preferably, the mounting site is on the top side of horizontal mounting surface  16 , which is flat or shaped to accommodate one or more batteries. The battery clamp is designed to provide stable support for the battery and still allow it to be easily removed. A second battery could be placed on the opposite side of the horizontal mounting surface as well. Even with two batteries, the motor assembly generally will weigh no more than about ten pounds, and in the configuration depicted in the drawings, weighs about four pounds (structural support, battery, and motor included). The motor alone generally weighs between about 4-14 oz.  
         [0023]    In an alternative embodiment, the battery mounting structure is a tongue-and-groove mounting system that mates with a corresponding tongue-and-groove structure on the battery itself. This simple system is especially preferred, because batteries useful in the invention often incorporate such tongue-and-groove structures in order to slide onto rechargers for recharging. Having a corresponding part as the battery mounting structure means that no tools at all are required for installing the battery or removing it for recharging. The user simply slides the fresh battery onto the mounting structure, attaches it to a connector leading to the motor, and the system is ready for use. To remove the battery, the user disconnects the battery from the motor and slides it off. Alternatively, a simple plug-in adaptor can supplement or serve as both a connector and support.  
         [0024]    The support bracket and motor are mounted above the wheel of the vehicle. On vehicles such as bicycles, scooters, and the like, the support structure is mounted on or over the front-wheel fork of the vehicle such that horizontal notch  30  fits over and comes to rest above the fork; vertical notch  32  straddles the wheel. As an alternative to clamp plate  47 , the scooter could be manufactured with a clamping plate permanently affixed to the fork to be pre-adapted for accepting the motor assembly. Alternatively, the entire drive-motor assembly may be permanently affixed to the frame of the vehicle, e.g., during manufacture of the vehicle, for a permanently powerable vehicle.  
         [0025]    The assembly is easily assembled in a short time using only simple tools. This configuration still allows the steering shaft and handle of the scooter to rotate freely to make turns. However, the support bracket provides an important safety feature as well, in that it prevents the scooter&#39;s front wheel from turning through 360 degrees by acting as a “bump stop” when the handle is rotated sufficiently that upper plate  29  hits and is stopped by guide plates  15  or support member  16 . This prevents a user from inadvertently turning the handle so hard or far that the scooter moves out from underneath the user.  
         [0026]    Optimal contact of the motor spindle and front wheel is that which provides sufficient frictional engagement between the spindle and the wheel to turn the wheel without slipping, but also without placing undue radial stress on the spindle. The adjustment means need not be threaded pins, and can be any manual or self-adjusting system which allows the spindle and motor to be raised and lowered to engage the wheel, for example, hydraulic or spring-loaded tensioning devices, slidable adjustors, and the like. The mechanism is easy to adjust, so that it can be readily adjusted as the wheel wears, for example.  
         [0027]    Because the motor and battery or batteries are mounted close together on the support structure, they are easy to connect together with a short connector. The motor is wired to an on/off switch, which can be mounted anywhere on the vehicle that is convenient for the user. For example, in a push scooter, the switch is preferably placed on the handlebar, and a simple wiring harness with an extendible link mounts to the outside of the steering column so that wiring does not get in the way of the rider and does not interfere with handle height adjustment or the collapsability of the scooter. The switch can be of any type, such as a momentary contact switch requiring constant user pressure to remain activated, or a finger-activated switch to selectively turn the motor on or off. Optionally, a low-power light may be provided in the assembly for safety or decoration. The light can draw from the battery or from self propulsion of the scooter by the user. When the motor is turned on, the light can also be turned on, and when the motor is off, then propulsion by the user turns the spindle on the motor which serves as a generator, generating sufficient power to light the light.  
         [0028]    Significant advantages of the motor and mounting assembly of the invention include that the entire unit is small and lightweight, and is contained in a single mounting. This makes it easy to carry and store. The unit is placed low on the scooter or other vehicle, so that it does not interfere with the rider and does not unsafely raise the center of gravity of the vehicle. The support bracket mounts over the wheel, with no additional supports or brackets required, and is attached and removed easily with hand tools.  
         [0029]    The front wheel installation allows the scooter to operate as an electric scooter or a push scooter, without removing the motor assembly or raising the spindle off of the wheel like prior-art motorized vehicles. Furthermore, as pertains particularly to a scooter, the front wheel mounting location allows the rider to have unfettered access to the rear friction braking system, so this important safety feature is not impaired in any way by the motor or batteries. The mounting assembly allows the user to quickly and easily change batteries, and the small size of the batteries permit the user to carry one or more spare batteries along if desired. Finally, the front-wheel drive system is more efficient and enhances performance.