Abstract:
A manually activated vehicle lift mechanism comprises a base and a vehicle support member with a generally two-piece, L-shaped, first-class lever pivotally connected to the base and forming the fulcrum point. The vehicle support member joins to an end of a shorter one of the legs of the L-shaped lever such that when its longer leg, i.e., its handle, is rotated in a first direction, the vehicle support is elevated. Rotation of the handle in an opposite direction again lowers the vehicle support.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
       [0001]    Not applicable 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    This invention relates generally to devices for elevating a vehicle from the ground and more particularly to a manual, lever-operated, lift mechanism for vehicles, such as lawn tractors, riding lawnmowers, golf carts, ATVs and the like, to allow ease of maintenance and servicing thereof. 
         [0005]    2. Discussion of the Prior Art 
         [0006]    There are disclosed in the prior art many devices that can be used for jacking up or elevating small vehicles, like motorcycles, lawnmowers, lawn and garden tractors, golf carts and the like, to facilitate maintenance and repair of the vehicles. They typically incorporate a base, a vehicle wheel support structure and a mechanism for elevating the wheel support structure from ground level to a predetermined height off of the ground. 
         [0007]    For example, the Drake U.S. Pat. No. 8,141,850 utilizes a relatively expensive tooth and ratchet mechanism along with a winch for raising a wheel support from the ground. 
         [0008]    The Bettencourt U.S. Pat. No. 6,966,542 utilizes a hydraulic jack to raise a four bar linkage that is coupled to a vehicle lift. The inclusion of the hydraulic jack necessarily increases the cost of manufacture of the overall lift device. Still other patents disclose electric motor-driven screws as a mechanism for raising wheel supports from a base. This, too, is a relatively costly approach. 
         [0009]    Additional examples of prior art include U.S. Pat. Nos. 7,823,861; 8,251,349; 8,540,214; 6,345,807; 6,338,470; 5,716,061; and 5,358,217. These prior art arrangements all have one thing in common. They are all relatively costly to produce when compared to the device described herein. 
         [0010]    It is accordingly an object of the present invention to provide a low cost, easy to operate vehicle lift mechanism utilizing a manually actuated lever to raise a vehicle wheel support mechanism from ground level to a height where servicing of the undercarriage of the vehicle can be carried out. 
       SUMMARY OF THE INVENTION 
       [0011]    In accordance with the present invention, a lift device for lawn care vehicles comprises a base having a pair of elongated bars connected in parallel spaced relation by a transversely extending bar member such that the base is arranged to sit on a ground surface. First and second elongated support arms are pivotally joined at a first end thereof to the base at a point adjacent the pair of elongated bars of the base. The arms are maintained parallel to one another by a tubular cross member pivotally coupled to the second ends of the first and second support arms. 
         [0012]    Projecting out from opposed ends of the tubular cross member are vehicle wheel supports. Completing the lift device is a lever mechanism for raising and lowering the vehicle wheel supports relative to a floor surface. The lever mechanism comprises an elongated handle member rigidly affixed at a predetermined angle to a lift bar. The handle member with the attached lift bar is pivotally attached to the transversely extending bar that is part of the base proximate its midpoint. The second end of the lift bar pivotally connects to the tubular cross member affixed to the outer ends of the first and second support arms. This somewhat L-shaped lever is designed such that as the handle member is manually moved by an operator toward the ground, the wheel supports reach an over-center position wherein the weight of the vehicle urges the handle more firmly against the ground, creating a stable condition of the lift where the vehicle wheel supports are in their elevated state. A pair of air springs is pivotally joined at one end to the pair of elongated bars of the base at points offset from the pivotal attachment of the arms to the base and at the other end to the arms. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0013]    The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description of a preferred embodiment, especially when considered in conjunction with the accompanying drawings in which: 
           [0014]      FIG. 1  is a perspective frontal view of the lift apparatus when in its lowered disposition; 
           [0015]      FIG. 2  is a frontal perspective view with the lift in its elevated disposition; and 
           [0016]      FIG. 3  is a view of the lift device when elevating a riding lawnmower. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0017]    This description of the preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top” and “bottom” as well as derivatives thereof (e.g., “horizontally”, “downwardly”, “upwardly”, etc.) should be construed to refer to the orientation as then described or as shown in the drawings under discussion, These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “connected”, “connecting”, “attached”, “attaching”, “join” and “joining” are used interchangeably and refer to one structure or surface being secured to another structure or surface or integrally fabricated in one piece, unless expressively described otherwise, Also, as used herein, “small vehicle” is meant to include riding lawn mowers, garden tractors, golf carts and ATVs. 
         [0018]    Referring to  FIGS. 1 and 2 , there is shown a view from the front of the manually operated small vehicle lift mechanism of the present invention. It is indicated generally by numeral  10  and in  FIG. 1  is seen to include a base  12  comprising a pair of elongated tubular bars  14 ,  16  of rectangular cross-section that are connected in parallel, spaced-apart relation by a transversely extending bar  18 . The base is designed to rest on a flat surface, such as on the around or on the floor of a garage or other workplace. Wheels, as at  19 , are appropriately journaled on the rear ends of the tubular bars  14 ,  16  to facilitate initial placement of the lift assembly, 
         [0019]    Welded to the bar  18  are angle bars  20  and  22  ( FIG. 2 ) that are spaced from one another. First and second elongated support arms  24 ,  26  are pivotally attached by hinge pins or bolts  28 ,  30  that pass through aligned holes in the elongated tubular bars  14 ,  16  and in a rear end portion of the elongated support arms  24 ,  26 . 
         [0020]    A tubular cross member  32  is pivotally connected to the forward ends  34 ,  36  of the support arms  24 ,  26 , using clevis brackets  37  and hinge pins or bolts  39 . 
         [0021]    Also seen in  FIGS. 1 and 2  is a pair of small vehicle wheel supports, indicated generally by numerals  38  and  40 , that are telescopingly fitted into the opposed ends of the tubular cross member  32 . The vehicle wheel supports may comprise an open, rectangular frame made up of front and rear, inner and outer bars  42 ,  44 ,  46 ,  48 , respectively. The length of these bars is set so that a predetermined arc of a small vehicle&#39;s tires will fit within the frames comprising the wheel supports  38 ,  40  as best seen in  FIG. 3 . Straps, as at  49 , join to the front and rear bars  42 ,  44  and are designed to wrap about the tires of a small vehicle. A suitable buckle  47  allows for tensioning of the strap on the tires. 
         [0022]    The wheel supports  38  and  40  further include a stub axle member  50  that is bolted or otherwise affixed to the inner frame bars  46 , The stub axle members  50  telescopingly fit within the lumen of the tubular cross member  32 . The stub axle members  50  are sized to permit limited rotation of the wheel supports  38 ,  40  about an axis extending through the length dimension of the cross member  32 . 
         [0023]    To raise and lower the wheel supports  38 ,  40  relative to the base  12 , a lever of the first class is operatively coupled between the spaced-apart angle bars  20  and  22  by a pivot pin or bolt  51  ( FIG. 2 ). More particularly, an elongated handle  52  has a lift bar  54  rigidly joined between bracket plates  53 ,  55  at one end thereof at a predetermined angle to a lower end portion of the handle  52 . The handle  52  with the lift bar  54  is pivotally coupled to the cross-bar  18  by which the bolt  51  serves as the lever&#39;s fulcrum. 
         [0024]    The free end of the lift bar  54  is pivotally joined to the tubular crossbar  32  proximate the midpoint by a clevis bracket  58  that is welded to the tubular crossbar  32  proximate its midpoint. A bolt or pin  59  is made to pass through aligned holes in the clevis bracket  58  and a front end portion of the lift bar  54 . 
         [0025]    As seen in  FIG. 2 , the handle  52  is bent at an obtuse angle at a location along its length, allowing a proximal portion thereof to lay flat on a floor while its distal portion slopes upward to the point at bracket  53  where the handle  52  joins to the lift bar  54 . 
         [0026]    It has also proved expedient to connect a pair of gas springs, as at  60 , between the base and the support arms  24  and  26 . In this regard, the free ends of the gas springs&#39; cylinders couple at a swivel  62  to the support arms  24  and  26  and the free ends of the gas springs&#39; pistons couple at swivels  64  to the elongated bars  14  and  16 . 
         [0027]    As an ergonomic aid, also attached to the transversely extending bar  18  of the base is a foot rest comprising a post  66  extending upward at an inclined angle to the base  12  terminating in a foot pad  68 . 
         [0028]    In operation, the lift mechanism  10  is tilted back on its wheels  19  by manually urging the handle  52  downward and then the assembly  10  is pushed so as to be positioned closely adjacent the front or rear wheels of the small vehicle to be elevated. The vehicle is then either manually pushed or driven so that its front or rear wheels fall within the frames comprising the wheel supports  38  and  40 , as best seen in  FIG. 3 . The operator next tightly wraps the straps  49  about the vehicle&#39;s wheels as a safety measure and applies a pushing force to an upper end of the handle  52 , thereby rotating it about the clevis bolt or pin  51  and ultimately bringing the proximal portion of the handle  52  to rest on the ground. As the handle is so rotated, the lift bar  54  rigidly affixed to the handle will rise from its lowered disposition shown in  FIG. 1  carrying the support arms  14 ,  16  and the tubular crossbar  32  with the wheel supports  38 ,  40  with it, thus raising one end of the vehicle from the ground as seen in  FIG. 3 . The gas springs  60  function to provide a lifting force as well, thus less exertion by the user is required. Repairs can now be more readily carried out on the vehicle&#39;s undercarriage. 
         [0029]    Because of the angle at which the lift bar is affixed to the handle, as the handle  52  is being lowered to the ground, the weight of the vehicle being elevated passes through an over-center point such that the proximal portion of the handle  52  is forced against the ground by the weight of the load being elevated. This prevents instability. To again lower the vehicle to ground, a predetermined lifting force must be applied to the handle to bring the handle back off the ground and past the over-center point where now the operator must exert a pulling force on the handle as the vehicle is being lowered to the ground. The gas springs  60  aid in assuring that the vehicle is lowered slowly rather than abruptly. 
         [0030]    A user may also wish to utilize the foot rest  66 ,  68  during lifting and lowering operation as a place to apply leg force as he or she manipulates the lever. 
         [0031]    Because the wheel supports are free to rotate with respect to the crossbar  32 , they can tip so that the front bars  42  abut the floor when the vehicle is driven onto the wheel supports, but then shift to a more horizontal disposition as the vehicle is being elevated. 
         [0032]    It has been found that with a lift bar 54 inches in length and the handle being ______ inches, an adult can readily elevate a load of ______ pounds using the above-described lift mechanism. 
         [0033]    This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.