Patent Publication Number: US-6338470-B1

Title: Powered lift for raising a two-wheeled vehicle

Description:
TECHNICAL FIELD 
     The invention relates to lift racks for maintenance of a two-wheeled vehicle. 
     BACKGROUND ART 
     In servicing a motorcycle, it is necessary or desirable to lift the motorcycle to make undercarriage vehicle components accessible for repair or maintenance purposes. Prior art mechanisms for lifting motorcycles usually include a platform connected to a base by an articulated linkage. The motorcycle is loaded on the platform when the platform is lowered toward the ground or floor surface that supports the lift. Provision is made in such known construction for actuating the linkage that connects the platform to the base using a fluid motor. An example of a construction of this type may be seen by referring to a catalog published by Autec Hofbruggen BV in the Netherlands. Lifts similar to the Autec lift have been used also to raise water craft and garden tractors for maintenance purposes. An example of a lift of this kind is disclosed in U.S. Patent Design 344,835. 
     In the prior art constructions, the lift track and the mechanism for lifting the motorcycle require the operator to wheel the motorcycle onto the platform which is raised from the surface that supports the lift track. Because of the weight of the vehicle, it is necessary to use a ramp device for raising the vehicle to the level of the platform before the platform is raised. Lift mechanisms of conventional design further require special stabilizing structural members for the motorcycle, which add to the overall weight of the lift. Further, the overall width of conventional lift mechanisms, including the load-supporting platform, is usually much wider than the transverse width of the motorcycle itself. This encumbers access to the undercarriage of the motorcycle for maintenance purposes. 
     DISCLOSURE OF INVENTION 
     It is an objective of the invention to provide a medium-weight lift rack assembly for a motorcycle and other two-wheeled vehicles wherein the vehicle can be wheeled by the operator onto the rack before it is raised. The operator thus can drive or roll the motorcycle onto the track and deploy the usual side stand prior to raising of the lift rack. The operator then can dismount the vehicle and secure the motorcycle properly before it is elevated. 
     The lift rack of the invention prevents transverse deviation of the motorcycle wheels by providing side walls on the base of the lift rack, which center the motorcycle on the lift rack. 
     The overall width of the lift track of the invention is narrower than the width of the motorcycle itself. This provides an unobtrusive profile for the lift rack and permits unencumbered access to the undercarriage of the motorcycle for maintenance purposes. 
     The motorcycle is lifted as the lift rack engages the motorcycle tires rather than the frame of the vehicle itself. This prevents possible damage to vehicle body work or paint. 
     The lift rack of the invention may be used in tandem with another lift rack of the same design to create a lifting mechanism for four-wheeled vehicles, such as lawn tractors or four-wheel all-terrain vehicles. 
     The lift rack includes an upper channel that is engaged by the tires of the vehicle. The upper channel has a base plate that rests on the ground or floor when the lift rack is lowered. A forward portion of the channel may be detachable from a main channel section. This permits the motorcycle front wheel to overhang the main track section for purposes of tire service or wheel removal without the necessity for using an external jack device. Rear wheel servicing also can be accommodated by reversing the position of the vehicle on the channel. 
     The lift rack assembly includes ground or floor engaging rails that are connected to the upper channel by parallelogram linkage elements or arms. A fluid motor, supported by the rails, activates the linkage elements to raise the upper channel. 
     A further feature of the invention is its lightweight design, which facilitates storage when the rack is not in use. Compared to known lift rack designs, the invention also improves the degree of safety in servicing the motorcycle because of its improved stabilizing characteristics. 
     The lift rack of the present invention can be adapted readily for storage by employing casters mounted on its forward end, thereby permitting an operator to raise the opposite end of the lift rack so that the assembly can be wheelbarreled to a storage location. A stabilizer bar is connected to the rails to provide lateral stability. A tie-down bar is connected to the upper channel to provide an anchor for tie-down straps connected to the vehicle. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 shows in perspective a raised motorcycle mounted on the lift rack of the invention; 
     FIG. 2 shows the vehicle and lift rack assembly of FIG. 1 wherein the front section of the track-engaging channel is lowered to permit access to the front wheel of the vehicle; 
     FIG. 3 is a detailed view of a yoke and yoke reinforcement for a fluid motor for raising lift linkage arms of the lift rack structure; 
     FIG. 3 a  is a side view of the yoke shown in FIG. 3; 
     FIG. 4 is a partial assembly view of the fluid motor, including the yoke of FIG. 3, for raising the articulated linkage arms for the lift rack structure of the invention; 
     FIG. 5 is an isometric view showing the fluid motor and forward linkage arms for the lift rack of the invention; 
     FIG. 6 is a subassembly view showing a forward channel section when it is secured to form an extension of a main channel section; 
     FIG. 7 is a view similar to FIG. 6 wherein the forward channel section has been moved away from the end of the main channel section; 
     FIG. 8 is an isometric view of the main channel section and the forward channel section seen in FIG. 7; 
     FIG. 9 shows a top view of the forward channel section and the main channel section; 
     FIG. 10 is a view of a bracket structure for connecting the forward channel section to the main channel section; 
     FIG. 11 is a plan view of the lift rack of the invention wherein caster wheels are assembled to the front end of the lift rack; and 
     FIG. 12 is a side elevation view of a portion of the lift rack and the caster assembly of FIG.  11 . 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     FIG. 1 shows in side elevation a motorcycle  10  having a forward wheel  12  and a rear wheel  14  resting on structural main channel  16 . The channel  16  includes side walls  18  and  20  on the lateral sides of a base plate  22 . The wheels rest directly on the base plate  22 . The side walls  18  and  20  prevent lateral displacement of the wheels relative to the base plate  22 . Base plate  22  rests on the ground or floor when the lift rack is lowered. 
     Ground or floor engaging rails  24  and  26  are located below the motorcycle supporting upper main channel  16 . Linkage arms or elements  28  and  30  are pivotally connected at their ends to the channel  16  and to the lower rails  24  and  26 . Additional pairs of linkage elements corresponding to linkage elements  28  and  30  are spaced longitudinally along the length of the channel  16  and the rails  24  and  26 , thereby defining a series of parallelogram linkages. 
     FIG. 2 shows the forward section  16 ′ of the main channel  16  in a lowered position. It is disconnected from the adjacent edge of the main channel  16 , thereby allowing the wheel  12  to overlie the main channel  16 . A block  32  is used to support the chassis of the motorcycle  10  when the wheel  12  overlies the main channel. This permits the wheel  12  to be located where it can be serviced easily by the operator. If the position of the motorcycle were to be reversed, as indicated in FIG. 1, servicing of the rear wheel is facilitated. 
     As best seen in FIGS. 8 and 9, a pair of angle brackets  36  and  38  is secured to the top surfaces  40  and  42  of the channel  16 . Corresponding brackets  36 ′ and  38 ′ are secured to top surfaces of channel section  16 ′. The brackets  36  and  38  and the corresponding brackets  36 ′ and  38 ′ each have a hole through which a locking pin is located. The locking pin for one side of the channel  16  is shown in FIG. 7 at  44 . It is received in an opening  44 ′ in the angle bracket  36 ′. A hitch clip, received through an opening in the pin  44 , holds the angle brackets in the engaged position shown in FIG.  6 . 
     FIG. 9 shows a top view of the connection between the forward section  16 ′ of the load-supporting channel and the main channel  16 . FIG. 10 shows a detailed view of the locking pin connection between the forward channel section and the main channel section when the brackets  36  and  36 ′ are disengaged. The hitch clip hole is shown in FIG. 10 at  46 . 
     FIG. 11 shows a mounting bar  48  secured to one end of the lift track structure. Casters  50  and  50 ′ are mounted on the bar  48 , as shown in FIG.  11 . at a spacing preferably greater than the width of the channel  16 . 
     The partial sectional view of FIG. 12 shows the mounting bar  48 , which may be in the form of a square structural section. The casters  50  and  50 ′ are supported on axle brackets  52 , which are joined to the bar  48  by bolts  54 . An angle bracket  56  is secured as shown to the bar  48 . It includes a floor engaging portion  58  that is slightly below the periphery of the caster  50 . This creates a clearance between the casters and the floor. The clearance is reduced to zero when the track is tilted in the direction of the arrow  59  in FIG.  12 . When the lift track structure is lowered to the floor-engaging position, the operator may move the lift track in a wheel barrel fashion to a storage area. 
     FIGS. 4 and 5 show a subassembly view of a hydraulic pump  60 . It includes a cylinder housing mounted on a support plate  62  secured to the rails  24  and  26 . The pump  60  includes a piston rod  64  secured to the center  66  of a yoke  68 , as seen in FIGS. 3 and 5. A reinforcement bracket  70  may be provided at the location of the connection between the piston  64  and the center  66 . The lower end of the arms of the yoke  68  are connected, as shown in FIG. 5 at  72  and  72 ′, to rearward linkage elements  28  and  30 . When the pump  60  is activated, the yoke seen in FIG. 3 will raise the linkage elements  28  and  30  to the position shown in FIG.  1 . All of the linkage elements  28  and  30  will move in unison because of the parallelogram construction of the lift track. The connection between the linkage elements and the linkage elements  28  and  30  may be about one-quarter to one-third of the distance from the lower ends of the linkage elements to the upper ends. 
     A stabilizer bar  74 , seen in FIGS. 2 and 5, is secured to one end of the rails  24  and  26  to provide lateral stability for the lift rack. 
     A tie-down bar  76  is connected to the top of the main channel  16  as seen in FIGS. 1 and 2. A tie-down strap  78 , which is connected to a frame member of the vehicle, is attached to each end of the tie-down bar to stabilize the vehicle on the lift rack. 
     Although one embodiment of the invention has been disclosed, it will be apparent to persons skilled in the art that modifications may be made without departing from the scope of the invention. All such modifications and equivalents thereof are intended to be covered by the following claims.