Abstract:
A drive wheel and suspension for a vehicle for mounting on a steering post to provide both a steering capability and propulsion to the vehicle. The drive wheel and suspension provides a spring suspension for that wheel of the vehicle, as well as what is effectively vehicle body mounting of the propulsion system so as to minimize un-sprung weight and to provide a compact assembly to support a suitable aesthetic and protective fender over the drive wheel and suspension.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of drive wheel suspension for vehicles. 
     2. Prior Art 
     T3 Motion, Inc., assignee of the present invention, now manufactures and sells the three-wheeled battery operated vehicle shown in  FIG. 1 . The vehicle is operated standing up, with all of the controls necessary being accessible on the handlebars. The vehicle has found wide application for security purposes, as it typically can operate all day in a typical application on a single charge, both indoors such as in shopping centers and outdoors for policing such areas as parking lots, parking structures, beach areas and the like. The vehicle has found wide use for such purposes not only because of its efficiency (cost of operation), but also because the operator is elevated somewhat, so can see over people for a better view of the area. 
     In the prior art vehicles as shown in  FIG. 1 , the wheels are rigidly mounted, that is, the rear wheels are rigidly mounted to the frame of the vehicle and the front wheel, which is the drive wheel, is rigidly mounted to the steering post, as in a typical tricycle. However because of the functionality and practical appeal of the vehicles, the same are being used in environments not having a particularly smooth operating surface, such as by way of example, poorly maintained parking lots and the like where rigid mounting of the vehicle substantially affects performance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view of a prior art vehicle in which the present invention may be used. 
         FIG. 2  is a first side perspective view of the suspension and drive of the present invention. 
         FIG. 3  is a second side perspective view of the suspension and drive system. 
         FIG. 4  is a front view of the drive and suspension of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention comprises a spring mounted drive wheel for an electric powered vehicle such as that shown in  FIG. 1 .  FIG. 2  is a first side perspective view of the suspension and drive,  FIG. 3  is an opposite side perspective view of the suspension and drive system, and  FIG. 4  is a front view thereof. A main crossbar  20  has a socket-like opening  22  therein to which a steering post will be fastened. Welded to the main crossbar  20  are a pair of downward and rearward projecting struts  24  which provide support for swing arms  26 , which support the axle  28 , which in turn supports wheel  30  on bearings (not shown) of conventional design. Between the upper ends of struts  24  and the forward part of swing arms  26 , just above axle  28 , are clips  34  which support coil springs  36 , each having a shock absorber  38  therein. The springs are generally chosen to support the weight applied to that wheel, with the swing arms  26  in a substantially level or horizontal position, as may be seen in  FIG. 3 . For the drive system, an electric motor  40  mounts on a plate  42  which is rigidly welded to the main crossbar  20  and further supported by a corner filler member  44  welded in place. The motor  40  has a toothed pulley  41  on the end of its shaft which drives a belt  46  that is connected to and drives a toothed pulley  48  supported on bearings on shaft  50 . Coupled to toothed pulley  48  is a hollow counter shaft  52  having a smaller toothed pulley  54  (visible only in  FIG. 3 ) having a toothed belt  56  driving wheel  30  and tire  31  through toothed pulley  48 . Shaft  50  may be rigidly fastened to the adjacent ends of swing arms  26  so as to form a rigid “U” shape with the legs of the “U” extending to each side of the wheel  30  and tire  31 , or not rigidly fastened, as desired. 
     Motor  40  is fastened to plate  42  by three bolts  57 , each in a slot  59  in plate  42 . This allows a screw  60  supported on plate  42  to be used to slide the motor toward main crossbar  20  before bolts  57  are tightened to provide the proper tension in belt  46 . Similarly, wheel  30  is supported on axle  28  which passes through a U-shaped clip  62  at each end of the axle. The swing arms  26  have a hollow rectangular cross section which is closed, at least at the end adjacent axle  28 , so that adjustment bolts  64 , together with jam nuts (best seen in  FIG. 4 ), may be tightened to slide axle  28  forward, away from each swing arm bearing in region  66  at each side of the suspension. This allows tightening of belt  56  as required, with the jam nuts then tightened to lock the adjustment bolts  64  in their set position. 
     Also visible in  FIG. 3  is a member  68  which is disposed to strip the toothed belt  56  from the toothed pulley  58  in the event of a break in belt  56 . A similar member  70 , supported from plate  42  by extension  72  as may be seen in  FIG. 2 , is disposed to strip the toothed belt  46  from the toothed pulley  48  in the event of a break in belt  46 . Also visible in these two Figures are straps  74 . These are merely support for a fender such as the front fender in the prior art unit of  FIG. 1 , which keeps foreign matter, clothing, etc. away from the belt drive. 
     The preferred embodiment has been described herein with respect to the use of toothed belts and toothed pulleys, though conventional belts may be used if desired. It will be noted from the indication of the direction of wheel rotation in  FIGS. 2 and 3  that the swing arms  26  project forward from their pivot axes as opposed to rearward for conventional swing arm suspension. By projecting forward, the tire may represent the forward most point of the system, yielding the appearance of the vehicle in accordance with  FIG. 1 . This also allows placement of the axis of rotation of the wheel somewhat forward of the axis of rotation of the steering column, as is normally done with tricycles, bicycles and motorcycles, and as is done in the prior art vehicle of  FIG. 1 . Reversing the arrangement shown in  FIGS. 2 to 4  so that the forward motion of the vehicle would be in the opposite would put the countershaft  52  and pulleys associated therewith forward of the tire, which would be both aesthetically and functionally undesirable. Having the swing arms projecting forward from the pivot point is facilitated in part by making the nominal position of the swing arms approximately horizontal and using the shock absorber/spring assembly as limiting of the swing arm motion. Accordingly the present invention enhances the functionality while preserving the appearance of a front wheel drive device such as the prior art vehicle of  FIG. 1 . Thus the present invention has a number of aspects, which aspects may be practiced alone or in various combinations or sub-combinations, as desired. While a preferred embodiment of the present invention has been disclosed and described herein for purposes of illustration and not for purposes of limitation, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the full breadth of the following claims.