Abstract:
A wheeled dolly adapted for transport and support of a vehicle wheel includes a base unit having a plurality of vertical, tubular support posts, with each of the posts terminating in a roller arranged to allow the base unit to be moved across a surface. A platform is adjustably attached to a top of the base unit and the platform includes a plurality of downwardly extending tubular posts sized and positioned to telescopically engage the support posts of the base unit. A top surface of the platform is configured to support a vehicle tire in an upright position. An electric motor and drive mechanism is coupled between the platform and the base unit such that operation of the motor and drive mechanism can lift and lower the platform through a predetermined distance. The drive mechanism uses an adjustable telescopic coupling between the platform and base unit to extend the range of movement between the platform and base unit.

Description:
SPECIFIC DATA RELATED TO THE INVENTION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/990,508 filed Nov. 27, 2007. 
     
    
       [0002]    This invention relates to a portable dolly for supporting and transporting a vehicle wheel that is being removed from or bolted onto a vehicle that is supported on a lift. 
         [0003]    The present invention is directed to a wheel lift or dolly which can be used by a mechanic or other person working on a vehicle in which the vehicle has been raised above ground level by a lift. For example, the vehicle may be in a garage and be elevated so that the wheels of the vehicle are approximately chest high to the person working on the vehicle. In this case, removal of a wheel in order to gain access to components of the vehicle hidden behind the wheel requires the mechanic or other person to remove the lug nuts holding the wheel to the vehicle and then to physically lift the wheel and lower it to the ground. In today&#39;s vehicles, the wheels on ordinary passenger vehicles have grown to be as large as twenty inch diameter and can weigh seventy or more pounds. This weight creates a risk of injury to the person lifting the wheel due to the awkwardness of the lifting and removal of the wheel from the vehicle and to the replacement of the wheel on the vehicle while the vehicle is in the raised position. 
         [0004]    A number of wheel dollies have been illustrated in the prior art. See, for example, the apparatus described in U.S. Pat. No. 7,334,804 and the patents cited therein. Some of these devices incorporate a hydraulic jack while others use a manual jack to raise a platform into position adjacent a wheel. One issue with the prior art devices is an inability to precisely position the dolly in support of the wheel such that pressure is released from the lug bolts holding the wheel to the vehicle during removal of the wheel and to accurately align the wheel with the lug nut holes during attachment of the wheel to the vehicle. In general, even with these prior art dollies using hydraulic jacks, it is generally been found that the mechanic or other person lifting the wheel must expend some effort to raise the wheel in order to have the wheel aligned with the lugs on the vehicle. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention overcomes the disabilities of the prior art in positioning of a lifting device or dolly to support a wheel for a vehicle by incorporating an electric motor actuated device that allows for precise positioning of the dolly height with respect to a wheel. The motor uses a gear box to drive a threaded shaft in an axial direction of the motor such that the shaft operates to create a displacement between the motor and the end of the shaft. The invention comprises a base unit and an attached platform adapted for supporting a vehicle wheel. The motor is connected to the platform and the threaded shaft is connected to the base unit such that the platform can be raised and lowered with respect to the base unit. The shaft and motor are configured to provide only a limited amount of movement of the platform with additional displacement being afforded by telescoping arrangement of posts supporting the platform to the base unit. In an exemplary form, the base unit uses four corner posts and the platform has four mating corner posts that telescope into the posts of the base unit. The post of both the base unit and the platform having mating holes that are uniformly spaced so that the relative position between the platform and base unit can be fixed by pins passing through aligned holes in the mating posts. The shaft of the motor is similarly coupled to the base unit using another cylindrical post so that the shaft can be pinned to the post allowing reaction between the shaft and post to lift the platform. 
         [0006]    In operation, the motor is actuated to lift the platform until a pair of holes in the mating posts of the platform and base unit are aligned. Pins are then inserted into the mating holes and the motor shaft retracted while the platform is supported on the pins. The motor shaft connection to the cylindrical post is then adjusted so that the shaft can again be used to lift the platform. The top of the platform may also be provided with a removal tray to allow the dolly to be used to support objects other that a wheel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a simplified view of the dolly of the present invention positioned in relationship to a vehicle for use in removing a wheel; 
           [0008]      FIG. 2  is front perspective view of the dolly of  FIG. 1  showing the general construction of the dolly; 
           [0009]      FIG. 3  is a front view of the dolly of  FIG. 2  showing the pin support arrangement for explaining the sequential lift function of the dolly; 
           [0010]      FIG. 4  is a partial cross-sectional view of a portion of the dolly of  FIG. 2  illustrating electrical wiring and hollow tube construction; 
           [0011]      FIG. 5  is a simplified cross-sectional view of the lift motor and shaft for electrical operation of the dolly lift function; 
           [0012]      FIG. 6  is a partial view of the dolly of  FIG. 2  showing how a wheel seats on the platform and is held in position for transport by an elastic strap; 
           [0013]      FIG. 7  is a perspective view of the platform portion of the dolly illustrating use of a removable tray; and 
           [0014]      FIG. 8  is a front view of  FIG. 7  showing engagement of the tray to the platform. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0015]    Referring now to  FIG. 1 , there is shown a simplified partial view of a vehicle  12  positioned on a conventional lift indicated at  14  such that a wheel  16  of the vehicle is raised to a height approximately at the chest of a person who would be working to remove the wheel from the vehicle. For purposes of this description, the wheel will be defined as including both the tire  18  and a metal hub  20  on which the tire is mounted. The lift or dolly of the present invention is indicated generally at  22 . 
         [0016]    The dolly  22  includes an upper portion or platform  24  that is supported on a base unit  23 . The base unit is constructed with four corner posts  26  although other numbers of posts could be used so long as the base unit is free standing. Further, the posts could be arranged in a different pattern than at the corners as illustrated. The corner posts  26  are interconnected by means of cross members  28 . Preferably, each of the posts  26  terminates in a roller  30 , which may be any of the several types of rollers, including wheels, that are commercially available to enable the dolly to be rolled on the floor of a garage. Rollers  30  are attached in a conventional manner. The top surface of the platform  24  is configured to support the vehicle wheel in the upright position as shown in  FIG. 1 . 
         [0017]    Turning now to  FIG. 2 , there is shown an enlarged view of the dolly  22  of  FIG. 1 . In this view, it can be seen that the upper platform  24  comprises a pair of metal side plates  32  and a bottom pan  34  that incorporates a curved section  36 . The curved section of the pan  34  provides a depressed area in the center allowing a pair of rollers  38  to be extended crosswise between the opposite side support members  32 . The rollers  38  rotate as shown by arrows  40  to allow a tire positioned on the rollers to be rotated about its axis. The rollers  38  may be attached to the side members  32  by means well known in the art such as by passing a large bolt through the rollers and the side members and fastening with nuts  42 . 
         [0018]      FIG. 2  also illustrates that the vertical support members  26  comprise an outer cylindrical member  44  and an inner cylindrical member  46 . The members  44  and  46  form a telescoping arrangement that allows the platform  24  to be lifted above the height of the outer members  44 . Each of the inner members  46  is provided with a plurality of holes  48  through which a pin  50  can be inserted in order to support the elevated position of the members  46  with respect to the outer members  44 . Each of the pins  50  is provided with a tether  52  to prevent them from being inadvertently removed from their position through the holes  48 . The upper ends of the members  44  may include a slot for seating of the pins  50  or holes may be provided through members  44  for the pins  50 . 
         [0019]    In a preferred embodiment, each of the support members  26  including both the outer cylindrical member  44  and the inner cylindrical member  46  are formed of metal to provide the required support and indestructibility of equipment needed in a garage operation. However, it is recognized that new developments in plastics may result in there being plastic materials that could be substituted for the metal supports. In the illustrated embodiment the metal supports  44  are joined together by metal cross brace members  28  that are welded at their ends to the members  44 . Preferably, each of the cross brace members  28  is a tubular member so as to minimize the weight of the dolly  22 . 
         [0020]    In the form illustrated in  FIG. 2 , there is provided a lower mounting housing  54  extending across the two lowest cross members  28  and attached thereto. Mounted on the housing  54  is a electrical junction box  56 . An electrical master switch  58  is also attached to the housing  54  with the associated electrical conductors extending within the  54  and into the box  56 . The master switch  58  may be utilized to turn off all power at the dolly  22 . As previously mentioned, the raising and lowering of the platform  24  is accomplished by an electric motor drive assembly. For this reason, the box  56  may include electrical connections for supplying power to the dolly from a conventional AC source in a shop. It will be recognized that the motor may be an AC or a DC motor. In the case of a DC motor, the box  56  would include circuitry for converting external AC poser to DC power. Similarly, if the box  56  is adapted to contain batteries for driving the motor, rectifying circuitry may be included to enable recharging of the batteries from an AC source. The design and construction of motor drive circuitry for either an AC motor or a DC motor are well known in the motor art. It may be advantageous to use a DC motor adapt the box  56  to receive rechargeable batteries that can be used to power the electric motor in the dolly so as to avoid the need for having to run cords from the dolly to an AC outlet. Electric power is supplied from the box  56  via the electric lines  60  coupled from the box to the electric motor illustrated generally at  62 . A conventional starter circuit for the motor  62  is associated with the box  56  and housing  54  with a starting capacitor indicated at  63 . A directional control switch  64  is mounted to one of the upper brackets  28  and allows the power to the motor  62  to be applied in a manner to either raise the platform  24  or lower the platform  24 . In essence, the switch  64  may be a rocker switch or a slide switch that enables power to be applied to the motor  62  to control the direction and amount of lift created by the motor. It should also be noted that the motor  62  incorporates an elongate shaft  66  which extends downward from a drive mechanism  62 A (see  FIG. 5 ) into another outer shaft  68 . Both the outer shaft  68  and inner shaft  66  are provided with matching holes  70  through which a pin  72  can be inserted. The spacing between the holes  70  is set to a small distance encompassing the range of motion of the shaft  66  being driven by the motor  62 . In other words, if the motor  62  is capable of advancing the shaft  66  approximately two inches, then the spacing between the holes  70  in a vertical direction would be selected to be approximately two inches. This allows the height of the platform  24  to be adjusted to within two inches of its final desired height and the motor to be used to make fine adjustments to the position of the platform  24  so as to accurately position the height of a wheel being removed from or placed on the vehicle. 
         [0021]    Referring now to  FIG. 3 , there is shown a front view of the dolly  22 . This view illustrates more clearly the operation of the lifting and lowering of the platform  24  with respect to the support members  26 . The motor drive assembly  62  is bolted or otherwise fixed to the underside of the platform  24  at the curved section  36 . The fastening may be done by means of a coupling  80  attached to the bottom of the curved section  36  by means of nut and bolt assemblies  82 . This arrangement fixes the position of the motor section  62  with regard to the platform  24 . The shaft  66  extends from an opposite end of the motor  62  and is moveable in a vertical direction as indicated by the arrow  84 . Shaft  66  is vertically movable via a screw drive arrangement within the motor  62  housing as is more fully shown in  FIG. 5 . The shaft  66  is telescopically mounted in a second outer shaft  68  so that the shaft  66  may telescope within the shaft  68 . During operation of the motor  62 , the shaft  68  and  66  are bolted together as indicated by bolt  86  so as to fix the shaft  68  to shaft  66  and to essentially create an extension of the shaft  66  supported on cross-member  88 . The shaft portion  68  extends through a hole formed in the cross member  88  and the pin  72  fits through the hole  70  to provide a support for the shaft  68  against cross member  88 . It will be appreciated that if the pin  72  is placed in the one of the holes  70  indicated by the dashed lines  90 , the actuation of the motor  62  to raise the platform will cause a reaction of the pin  72  against the cross member  88 . As the platform  24  is raised by operation of the motor  62 , the inner supports  46  within the outer supports  44  will telescope outwardly allowing the platform to be raised. The pins  50  can then be placed through the hole  48  in the inner member  46  so as to support the platform  24  at a desired height. The platform  24  may be smoothly adjusted between the distances represented by adjacent pairs of the holes  70  by use of the motor  62 . For adjustments beyond that range, the system utilizes a sequence of raising and lowering with placement of the pins  50  and  72  to allow the platform to be adjusted to any desired height. For example, with the pins  50 ,  72  inserted in the locations shown in  FIG. 3 , the platform  24  can be raised by motor  62  and shaft  66  until pins  50  can be removed and inserted into the next set of holes  48 . The motor  62  is then operated in a reverse direction to withdraw shaft  66  toward the motor while the platform is supported by the pins  50 . The pin  72  is then withdrawn and reinserted into a new position and the motor again operated in a forward direction to lift the platform using reaction of the shafts  66 , 68  combination against member  88  at the new position of pin  72 . In this manner, the platform  24  can be raised or lowered in a series of steps while the position between each of the steps or pin positions is accurately controlled by use of the electric motor  62 . 
         [0022]      FIG. 4  is provided to illustrate how the electrical connections extending from the connection box  56  are routed to the upper cross member  28  containing the toggle switch  64  so as to allow the motor  62  to be operated in either a forward or reverse direction. 
         [0023]    Turning now to  FIG. 5 , there is shown a partial cross-sectional view of a typical stepper motor of the type utilized as motor assembly  62 . A conventional stepper motor includes an electrical drive motor  90  that may be operated in either a forward or reverse direction. An output shaft of the motor  90  is connected to drive mechanism  62 A that comprises a plurality of drive gears illustrated generally at  92  to form a gear box that reduces the speed of the motor shaft to a suitable drive speed for driving a screw type gear  94  coupled to output shaft  66 . The screw  94  is coupled in a conventional manner to the shaft  66  to enable shaft  66  to move in and out of the motor drive mechanism  62 A as the motor shaft rotates. 
         [0024]      FIG. 6  illustrates the use of an elastic cord  96  to hold a wheel  18  onto the platform  24 . The cord  96  may not be necessary but does provide a degree of safety to prevent the wheel from falling off of the platform while the platform is being moved to or from the vehicle  12 . 
         [0025]      FIG. 7  is a partial top perspective view of the dolly  22  illustrating a sliding tray  98  that can be used with the dolly to support objects other than a wheel. For example, the tray  98  may be used to transport other automotive parts or to place tools while working around a vehicle.  FIG. 8  is a front view of the tray  98  on the dolly  22  showing how the tray is provided with guide supports  100  that engage with runners  102  on dolly  22 . In a simple form, the runners  102  are “angle irons” with an L-shaped cross section. The runners are fastened to the upper side plates  32  of the dolly such as by bolts, rivets or welding with one arm of each L-shaped runner extending outwardly from the side plates  32 . The guide supports  100  may also be angle irons of the same configuration that are fastened to side plates  104  of the tray  98 . The supports  100  are oriented reversibly from the runners  102  so that one arm of the L-shaped support extends under the outwardly extending arm of the runners. The top of the runners  102  are provided with a plastic surface  106  to facilitate sliding motion of the tray on the runners. In addition, the surface  106  may incorporate magnetic strips  108  that can be used to retain small items such as nuts  110  to prevent them from being misplaced while working on a vehicle.