VEHICLE MOUNTED LIFT ASSEMBLY
A lift assembly connects to a receiver hitch and utilizes a plurality of parallel arms connecting a vertical mounting post to a center support in a lift frame that is raised and lowered by the lift assembly. The lift assembly is configured so that the parallel arms rotate from vertical to an inclined angle as the lift frame is lowered, but the arms do not extend below the horizontal as they extend rearward from the mounting post.
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The subject patent application is a continuation of co-pending U.S. patent application Ser. No. 12/423,634, filed on Apr. 14, 2009, which is now U.S. Pat. No. 9,096,160, the disclosure of which is hereby incorporated by reference.
FIELD OF THE INVENTIONThe present invention relates to a lift assembly that may be mounted on a vehicle and particularly to an assembly mounted to a trailer hitch in a fashion providing mechanical advantage to facilitate lifting and lowering of the assembly.
BACKGROUND OF THE INVENTIONNumerous lift assemblies have been designed for attachment to vehicles and most commonly to facilitate loading and unloading from a truck tailgate. Many of the prior art tailgate lift assemblies require integration into the side wall or bed of the vehicle in order to adequately support the lift assembly and weighted load. Powerful hydraulics or lift drives are also required for many of these lift assemblies, if the lifts are intended to be used with substantial loads.
The integration of lift assembly mounts into the side rail or bed of a vehicle is difficult and expensive, both in time and material. Devices have been provided where a mechanism for a tailgate lift utilizes cables, such as in U.S. Pat. No. 4,601,485, screw drives as shown in U.S. Pat. No. 3,180,503; and power from a winch mounted on the vehicle as shown in U.S. Pat. No. 6,609,481.
Some devices have even been designed to mount on a trailer hitch as in U.S. Publication No. 2007/0280807 disclosing a carrier with a screw drive to adjust the height, and U.S. Publication No. 2001/0014272 disclosing a lift connected to its hitch mounted yoke by pairs of parallel support bars. However, this latter publication is inoperable in practice because the lift is allowed to pivot so that the support bars extend both upward and downward from the yoke, causing a situation that requires vertical force to raise and lower the lift.
These and other devices of the prior art fail to be easily integrated with presently existing vehicles and require extensive engineering and manufacturing to mount and operate effectively.
In the prior art there does not exist a simplified unit for providing a vehicle mounted lift assembly, that can be hitch mounted, and providing mechanical advantage so that loads may be lifted manually or with relatively small motors contained within the lift assembly.
BRIEF DESCRIPTION OF THE INVENTIONThe present invention resolves at least some of the above disclosed shortcomings of the prior art. A vehicle mounted lift assembly of the present invention may be adapted to easily fasten to a vehicle, and preferably to a hitch assembly, provides mechanical advantage that permits manual lifting or lifting with a motor contained within the lift assembly, of loads up to at least about 500 pounds, utilizes pairs of parallel support arms to connect the vehicle mounting section to the lift frame, and does not permit the pairs of parallel connecting arms to extend from the mounting section at an angle below the vertical. The lift assembly is especially adapted for the carriage of a portable grill apparatus, however, the lift frame is easily adapted to carry conventional loads.
It is, therefore, an object of the present invention to provide a removable vehicle mounted lift assembly that does not require special integration into the bed, side rails or frame of the vehicle. It is a further object of the invention to provide a vehicle mounted lift assembly which may be easily manufactured and that may provide for mechanical advantage in lifting a load of significant weight for carriage by the vehicle.
These and other objectives of the invention may be more readily seen in the accompanying figures of an exemplary lift assembly in which:
Turning then to
Turning again to
In order to operate the lift assembly 20 and lower the lift frame, the first and second parallel arms 30, 31 are moved from a vertical position in the forward plane of the lift frame where in the illustrated embodiment, arm channels 36 receive the vertical mounting post 23, and in turn the first and second parallel arms 30, 31 and mounting post 23 are received within the center support channel 41, to the extended position shown in
Turning then to
Therefore, in transport mode, the vertical mounting post 23, parallel arms 30, 31 and center support 40, are all preferably aligned in a substantially vertical orientation about one another, or at least within the forward plane of the lift frame, and the bottom frame member 51 of the lift assembly 20 is carried at a safe clearance distance 29 above the ground. When lowered, the center support member 40 is unlocked from the vertical mounting post 23 and the first and second parallel arms are rotated out of vertical into a angular orientation rising at angle βfrom the attachment of bottom arm openings 34, 35 near post bottom 26 to top arm openings 38, 39 that are fastened at the top center support openings 42 of the lift frame. It will be seen that according to the Pythagorean theorem, the length L of the displacement of center support post 40 from vertical mounting post 23 can be computed according to the formula where the sum of the displacement length squared plus the square of the difference V in vertical height between top center support openings 42 of the lowered lift frame and bottom post openings 27 of the vertical mounting post 23 is equal to the square of the length of the parallel arms, 30, 31 between their opposed retaining axis points. This provides the designers of lift assemblies according to the present invention with guidance in optimizing the lift design for various functions such as the illustrated portable grill carrier, a game lift for hunters, a frame for cargo transport, and other lift assembly uses.
All publications, patent, and patent documents mentioned herein are incorporated by reference herein as though individually incorporated by reference. Although preferred embodiments of the present invention have been disclosed in detail herein, it will be understood that various substitutions and modifications may be made to the disclosed embodiment described herein without departing from the scope and spirit of the present invention as recited in the appended claims.
Claims
1-22. (canceled)
23. A lift assembly for a vehicle having a hitch receiver, said assembly comprising:
- a mounting portion having a top and a bottom with said mounting portion adapted for attachment to the hitch receiver of the vehicle;
- a lift frame coupled to said mounting portion and having a center support member defining a channel with said lift frame defining a forward plane; and
- first parallel arms having first bottom ends fastened to said bottom of said mounting portion, and having first opposite ends fastened to said center support member of said lift frame such that said first parallel arms extend in a nearly vertical orientation when said lift frame is in a raised position and extend rearward outward from said mounting portion in an upward orientation when said lift frame is in a lowered position;
- wherein said first parallel arms and a portion of said mounting portion are aligned in a vertical orientation about one another and are received within said channel of said center support member rearward of said forward plane when said lift frame is in said raised position.
24. A lift assembly as set forth in claim 23 further including second parallel arms having second bottom ends fastened to said bottom of said mounting portion, and having second opposite ends fastened to said center support member of said lift frame such that said second parallel arms extend in a nearly vertical orientation when said lift frame is in said raised position and extend rearward outward from said mounting portion in an upward orientation when said lift frame is in said lowered position.
25. A lift assembly as set forth in claim 24 wherein both of said first and second parallel arms and a portion of said mounting portion are aligned in a vertical orientation about one another and are received within said channel rearward of said forward plane when said lift frame is in said raised position.
26. A lift assembly as set forth in claim 25 further including a locking device engaging at least one of said first and second parallel arms, a portion of said mounting portion and a portion of said center support member when said first and second parallel arms and said portion of said mounting portion are in said channel to maintain said alignment in said vertical orientation about one another.
27. A lift assembly as set forth in claim 26 wherein said locking device is further defined a locking pin directly engaging at least one of said first and second parallel arms, an opening in said center support member and an opening in said mounting portion.
28. A lift assembly as set forth in claim 24 wherein second bottom ends of said second parallel arms are fastened to said bottom of said mounting portion rearward of said first bottom ends of said first parallel arms, and second opposite ends of said second parallel arms are fastened to said center support member rearward of said first opposite ends of said first parallel arms.
29. A lift assembly as set forth in claim 23 wherein said first bottom ends of said first parallel arms are fastened to said bottom of said mounting portion by a first bottom retaining axis, and said first opposite ends are fastened to said center support member by a first top retaining axis.
30. A lift assembly as set forth in claim 29 wherein said first bottom retaining axis and said first top retaining axis are in the form of bolts.
31. A lift assembly as set forth in claim 24 wherein said second bottom ends of said second parallel arms are fastened to said bottom of said mounting portion by a second bottom retaining axis, and said second opposite ends are fastened to said center support member by a second top retaining axis.
32. A lift assembly as set forth in claim 31 wherein said second bottom retaining axis and said second top retaining axis are in the form of bolts.
33. A lift assembly as set forth in claim 23 wherein said upward orientation of said first parallel arms is at least 25 degrees above horizontal when said lift frame in said lowered position.
34. A lift assembly as set forth in claim 24 wherein said upward orientation of both of said first and second parallel arms are at least 25 degrees above horizontal when said lift frame in said lowered position.
35. A lift assembly as set forth in claim 23 wherein said mounting portion includes a horizontal attaching member adapted for attachment to the hitch receiver, and a vertical mounting post defining said top and said bottom.
36. A lift assembly as set forth in claim 23 wherein said lift frame further includes a top frame member and a front bottom frame member with said top frame member, said front bottom frame member and said center support member defining said forward plane.
37. A lift assembly as set forth in claim 23 further including a motor mounted within said lift frame to provide powered raising and lowering of said lift frame.
38. A lift assembly as set forth in claim 37 further including a cable connected between said motor and said mounting portion with said motor retracting and extending said cable to raise and lower said lift frame.
Type: Application
Filed: Aug 4, 2015
Publication Date: Jan 28, 2016
Applicant: (Vaughan)
Inventor: David L. LeAnna (Duck River, TN)
Application Number: 14/817,818