Abstract:
The disclosed invention is a portable vehicle lift for elevating a motor vehicle. The lift includes spaced apart beams which are positioned under the vehicle, each beam has a plurality of hinged strut pairs, each with associated threaded collars. Strut pairs are moved together or apart by directionally rotating a threaded shaft through the threaded collars. Supplemental lift springs may be positioned along the shaft to selectively engage and urge the strut pairs during operation.

Description:
CROSS REFERENCE TO RELATED PROVISIONAL PATENT  
       [0001]     This non-provisional application claims priority of the provisional application NO. 60/530,109 filed on Dec. 15, 2003. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention generally relates to an improved portable vehicle lift for elevating a motor vehicle. More particularly, a lift is provided which has spaced apart beams for positioning under the frame or tires of the vehicle, each beam further having a plurality of hinged struts movable along threaded shafts and whereby directional rotation of the threaded shaft selectively elevates or lowers the struts and attached beam members.  
       BACKGROUND OF THE INVENTION  
       [0003]     Numerous types of jacks and vehicle lifts have been patented to perform the same basic function of lifting a portion, or all, of a motor vehicle for service, repair, and even storage. Generally, jacks are manually operated devices used to lift one of four comers, or either the front half or back half of the vehicle off of the ground. Vehicle lifts are generally positioned under the vehicle tires or the vehicle frame, and through powered mechanisms such as hydraulic power, gears, pulleys and chains, and the like, elevate the entire vehicle off the ground.  
         [0004]     The instant invention is a hybrid of a lift and a jack, in that it is a mechanically operated device that is used to lift the entire vehicle off of the ground. The inventive lift has few parts and is very easy to operate and is relatively inexpensive to manufacture. It is anticipated that the preferred use for the inventive device will be for “driveway mechanics” or individuals who work on their vehicles in their driveways or personal garages. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]     The invention is illustrated using the following figures along with the detailed description of the invention:  
         [0006]      FIG. 1  is a perspective view of the inventive device.  
         [0007]      FIG. 2  is a perspective view of the device in an elevated orientation.  
         [0008]      FIG. 3  is a partial perspective view of the device in an elevated orientation.  
         [0009]      FIG. 4  is a partial plan view of the inventive device.  
         [0010]      FIG. 5  is a partial end view taken along line  5 - 5  of  FIG. 4 .  
         [0011]      FIG. 6  is another partial end view of  FIG. 5 .  
         [0012]      FIG. 7  is a partial view showing a spring assembly of the inventive device. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0013]     The present invention relates to an improved mechanical vehicle lift having spaced apart beam members for positioning under the chassis, frame or tires of a motor vehicle and by which the vehicle may be vertically elevated through mechanical actuation of a series of struts and threaded shafts.  
         [0014]     Referring now generally to  FIG. 1 , the preferred embodiment of the vehicle lift  100  includes a left beam member  102  and a spaced apart right beam member  104 . It is to be understood that the left beam member  102  and right beam member  104  are substantially identical and for the purpose of brevity, only one of the beam members will be described in detail.  
         [0015]     Each beam member  102 ,  104  further includes a substantially rectangular frame  106 , preferably formed of channel or box steel. The frame  106  is formed from a spaced apart, parallel pair of side members  108 ,  110  and a spaced apart and parallel pair of end members  112 ,  114 , one at either end of the longitudinal members and rigidly fixed thereto to complete the substantially rectangular frame  106 . A beam plate  116  generally overlies the frame  106  extending beyond each end  112 ,  114  as best shown in  FIG. 1 . The beam plate  116  has multiple channels  118  formed down each side as shown in  FIGS. 2 and 4 .  
         [0016]     Two pairs of struts are rotatably mounted to the longitudinal members of the frame. More particularly, a first pair of struts is positioned at one end of the frame  106  and a second pair of struts is positioned at the opposite end of the frame  106 . Each pair of struts comprises a first and second outer strut arm  122 ,  124  positioned on the outside of the rectangular frame  106  and a third and fourth inner strut arms  126 ,  128  positioned inside of the rectangular frame  106 . The second pair of struts are located at the opposite end of the frame member and in the same orientation as the first set of struts. As best shown in  FIGS. 1 and 2 , the beam  116  comprises the center portion of the assembly, the inner strut arms  126 ,  128  are positioned on either side of the beam, the frame  106  is then outboard the inner strut arms  126 ,  128  and finally, the outer strut arms  122 ,  124  are outboard the frame  106 .  
         [0017]     A long pin  130  is used to pivotally secure a first end of the outer strut arms  122 ,  124  substantially near the end of the frame  106 . It should be understood that two short pins could be used to independently secure each strut arm to the frame. A second long pin  132  slidably maintains the second end of the outer strut arms  122 ,  124  within one of the channels  118  of the beam as best shown in  FIG. 2 . A third long pin  134  pivotally attaches the inner strut arms  126 ,  128  generally near the center of the frame. A fourth long pin  136  slidably maintains the second end of the inner strut arms  126 ,  128  to the center beam  116  through one of the slotted channels  118 . This orientation is replicated at the opposite end of the lift, as shown in  FIG. 2 .  
         [0018]     In the lower position, each lift is folded substantially flat because of the orientation of the inner  126 ,  128  and outer  122 ,  124  strut arms positioned on either side of the frame  106  with the center beam  116  fitted between the inner strut arms  126 ,  128 . As shown in  FIG. 2 , the second pin  132  of the outer strut arms  122 ,  124  and the fourth pin  136  of the inner strut arms  126 ,  128  are positioned through the slotted channels  118  formed in the center beam  116 . This allows the second or upper ends of the strut arms  122 ,  124 ,  126 ,  128  connected to the beam  106  to slide along the length of the beam  106  as the strut arms are elevated and lowered. The length of the slots  118  limit the height of the beam  106  as each pin engages the slot end.  
         [0019]     Referring to  FIG. 3 , the lift is shown without the beam  106  in place, displaying a full view of the lifting mechanism. Two threaded collars  138 , preferably acme collars, are positioned on each strut pair, as shown with one on the second pin  132  of the outer strut arms  122 ,  124  and the fourth pin  136  on the inner strut arm  126 ,  128 . A threaded shaft  140 , preferably an acme threaded shaft, is passed through the threaded collars  138 . As the threaded shaft  140  is rotated in a first direction, the threads of the shaft  140  forcibly move the collar  138  of the inner strut pin  136  towards the acme collar  138  position on the outer strut pin  132 . This causes the respective struts to elevate as the collars move toward each other. As the shaft  140  is rotated in a second direction, the collars  138  are forced apart along the threads of the shaft declining the respective strut arms. This orientation is replicated on the other strut pair of the lift beam such that each lift beam includes a total of four threaded collars spaced along the threaded shaft  140 .  
         [0020]     As best shown in  FIGS. 3 and 4 , the inner pair of strut arms  126 ,  128  is preferably connected to the outer pair of strut arms  122 ,  124  with a single long threaded shaft  140 . This configuration allows both pairs of strut arms to be elevated simultaneously in precise increments. A miter gear  142  may be positioned on the threaded shaft intermediate the two pairs of strut assemblies. This allows the left and right beam assemblies to be elevated simultaneously with a long connecting crank  144  as best shown in  FIGS. 3 and 6 .  
         [0021]     While the vehicle lift is operable as described above, it is preferable to include coiled springs between the strut arm pairs to supplement the lifting force of the struts and to decrease the required power to elevate the beams. As shown in  FIGS. 3 and 4 , an outer shaft seat  146  is fixed at each end of the threaded shaft  140 . An inner shaft seat  148  is fixed adjacent to and on either side of the miter gear  142 . Four coil springs  150 ,  152 ,  154 ,  156  for each strut pair are provided, with two springs  150 ,  152  positioned slightly below and on either side of the threaded shaft and oriented generally outboard and two springs  154 ,  156  positioned slightly below and on either side of the threaded shaft and oriented generally inward. Each of the springs  150 ,  152 ,  154 ,  156  have a first end  158  mounted to or near the threaded collar  138  on the fourth long pin on the outer strut arms  122 ,  124 . The first end  158  is generally mounted to a bolt  159  depending from the beam  116 . The second end  160  of each spring  150 ,  152 ,  154 ,  156  projects laterally away from the first spring end  158  substantially along the threaded shaft  140 . At the second end of each spring  160  a hook  162  is formed and oriented generally upward toward the threaded shaft  140 .  
         [0022]     Two force nuts  164 ,  166  are positioned on the threaded shaft  140 , for each strut arm pair. The first nut  164  is between the inner shaft seat  148  and the threaded collar  138  on the second long pin  132 , and the second nut  166  is between the outer shaft seat  146  and the threaded collar  138  on the fourth long pin  136 . This configuration is replicated on the opposite of the miter gear such that a total of four force nuts are on the threaded shaft of each beam member. The force nuts  164 ,  166  have opposing thread configurations such that as the threaded shaft is rotated they move in opposite directions. In the lowered position, the hooks  162  are in contact with the force nuts which extend the springs thereby imparting generally inward directional spring force from the spring onto the force nut. As the shaft  140  is rotated to elevate the beam, the force nuts move inward with the elevating threaded collars  138  and the inward spring force urges the nuts and associated threaded collar inward as the beam elevates. The force nuts disengage from the spring hooks as the lift continues to elevate.  
         [0023]     As the threaded shaft  140  is rotated to lower the beam, the force nut  164  moves toward the inner shaft seat  148  and the second force nut  166  move toward the outer shaft seats  146 . As the lift is lowered, the force nuts  164 ,  166  engage the hooks  162  on each spring  150 ,  152 ,  154 ,  156 . It is preferable that each force nut be provided with a hook receptacle  168  which retains the end of each hook  162  as shown in  FIGS. 5 and 6 .  
         [0024]     As shown in  FIGS. 5 and 6 , as the threaded shaft  140  is rotated directionally to elevate the strut assemblies and associated beam members, the resilient springs which are connected at or near the second and fourth pins, engage the drive nuts as the drive nuts move outboard along the threaded shaft. The extension of the resilient springs impart stabilizing directional forces along the threaded shaft to reduce vibration during elevation of a vehicle and impart longitudinal forces along the threaded shaft to assist in the lifting of the beam member. The fourth drive nut is provided with a receptacle which engages a hook formed on the resilient springs.  
         [0025]     It is preferable to include pairs of compression springs, outer compression springs  170  mounted on the outer shaft seat oriented inboard and inner compression springs  172  mounted on the inner shaft seat oriented outboard. These springs provide lift assistance as the beams first begin lifting and also cushion the downward forces as the beam is lowered to its lowermost point.  
         [0026]     In yet another embodiment of the invention, a single pair of springs is utilized for each strut pair for a total of four springs per lift beam member. In this configuration, a resilient spring is mounted to the outboard rod seat and the inner shaft seat on either side of the threaded rod. In yet another embodiment of the invention, drive nuts are provided on the outer shaft seat and the inner shaft seat.  
         [0027]      FIG. 7  shows the orientation of a pin through a strut pair with the attachment point for the first end of resilient springs  150 ,  152 ,  154 ,  156 , generally a pin, bolt or similar fastener  159 . This fastener may also be positioned completely through the beam plate  116 .  
         [0028]     In operation, the left and right side beam assemblies are connected with a connecting rod  144 . The beam assemblies are then positioned substantially under the frame of the vehicle to be lifted. It is preferred the lift be positioned substantially between the front and rear tires of the vehicle and directly under the frame members. The crank is then attached to the center link and rotated in the first direction. The actuation of the crank causes the threaded shafts to turn in the miter gears and the threaded collars. The pins located in the threaded collars of each strut pair are forcibly moved together causing the strut arms to elevate. As the strut arms elevate, the pins slide in the provided channels on the center beam. The length of these channels limit the elevation height. To lower the vehicle, the crank is turned in the second rotational direction to reverse the threads in the threaded collars forcibly moving the strut arms away from each other, thereby lowering the center beam and the elevated vehicle.  
         [0029]     This lift can be manually cranked, however, it is preferable to use an electric motor  176  attached via a crank rod  174  to turn the crank assembly. Use of the spring and force nut configuration decreases the size of the motor required to elevate a vehicle.  
         [0030]     Casters or wheels may be mounted at each corner of the frame so that the device can easily be rolled under a vehicle. It may be possible to attach casters of enough strength so that, upon elevation of the vehicle, the entire vehicle can be rolled on the beam assemblies.  
         [0031]     It will be apparent to those skilled in the art that various modifications and variations can be made in this vehicle lift of the present invention without departing from the spirit or scope of the invention. The present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.