Abstract:
A folding table is provided with a foldable leg structure. The legs fold between a first working position and a second stored position. As the legs move towards the stored position, a pair of wheels associated with the legs structure are moved into operative position, enabling the table top to be rolled easily to storage.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from Provisional application Ser. No. 60/137,910, filed Jan. 7, 1999. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     This invention relates to folding table structures, and in particular, to a leg structure which operates to move wheels into an operative position in the folded position of the legs, enabling the table to be moved easily. 
     Folding tables are well known in the art. They commonly are used in homes, offices, training rooms, cafeterias, etc. when extra table space is needed. When not needed, the tables are folded up and stored in some convenient manner. 
     The prior art reveals a number of structures which are designed to enable a working surface, for example, a table, to be moved from its working position to its stored condition. In general, these structures tend to be complicated, and are designed to be associated with the ground engaging end of the leg structure. The prior art references of which we are aware include U.S. Pat. No. 3,799,073, issued Mar. 26, 1976; U.S. Pat. No. 3,861,325, issued Jan. 21, 1975; U.S. Pat. No. 3,557,720, issued Jan. 26, 1971; U.S. Pat. No. 4,932,333, issued Jun. 12, 1990; U.S. Pat. No. 5,615,451, issued Apr. 1, 1997 and U.S. Pat. No. 4,779,542, issued Oct. 25, 1988 . While each of these prior art references work for their intended purposes, as indicated above, they have approached the mobility problem for folding tables by assuming that the wheels associated with the folding table should be associated with the ground engaging end of the leg structure. We have devised a simple folding table leg structure which mounts the wheels along the underside of an associated tabletop, interconnecting the wheels with the underside in a manner that moves the wheels relatively outwardly from the underside of the table as the leg structure is moved to its folded position. Thereafter, either end of the tabletop can be lifted and wheeled in a manner similar to the operation of wheelbarrow, for example, to a second location. In the stored position of the wheels (i.e., the operative position of the table), the wheels are hidden from normal view. Even if seen, however, the wheels appear to be a part of the leg structure so that they are aesthetically pleasing and yet extremely functional in operational use. 
     BRIEF SUMMARY OF THE INVENTION 
     One of the objects of this invention is to provide a folding leg structure which provides wheels for movement of an associated table top. 
     Another object of this invention is to provide a low cost folding table structure which includes a wheel structure. 
     Yet another object of this invention is to provide a wheel structure for a tabletop which incorporates the wheels in a manner that is aesthetically pleasing in function and use. 
     Yet another object of this invention is to provide a fold up table which includes adjustable leg structure. 
     Other objects of this invention will be apparent to those skilled in the art in view of the following description of the accompanying drawings. 
     In accordance with this invention, generally stated, a table has at least one leg structure operatively associated with the underside of the table. The leg structure, in turn includes at least one wheel associated with the leg structure. In the preferred embodiment, a pair of wheels is associated with each leg structure. The leg structure includes the wheels themselves, and a link between the leg structure and the underside of the table, permitting the legs to be moved between a first working or table supporting position and a second folded position. Movement of the legs towards the second position operates to move the wheels from a first position near the underside of the table to a position relatively further from the underside. In the preferred embodiment, the legs also are adjustable to provide various table heights. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     In the drawings, 
     FIG. 1 illustrates an illustrative embodiment of foldable table employing the leg structure of our new design; 
     FIG. 2 is a view in side elevation of the table shown in FIG. 1; 
     FIG. 3 is a bottom plan view of the table shown in FIG. 2; and 
     FIG. 4 is a view in side elevation. 
    
    
     Corresponding reference numerals will be used throughout the several figures of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1, reference numeral  1  indicates one illustrative embodiment of foldable table of the present invention. The table  1  includes a top  2 , having an upper side  3  and a lower side  4 . A pair of beams  5  and  5 ′ extend along the underside  4  of the table in a conventional manner. The embodiment illustrated includes a pair of leg structures  6  and  7  associated with the underside of the table  1 , as later described in greater detail. As will be appreciated by those skilled in the art, the top  2  of the table  1  may assume a variety of designs, and any of those designs are compatible with the broader aspects of the present invention. 
     The leg structures  6  and  7  are identical and for purposes of brevity, only a single leg structure is described in detail. Those skilled in the art also will recognize that our invention may find utility in constructions where only a single leg structure is employed. For example, one end of the table maybe removably mounted to a wall or other supporting structure while the leg structure  6  provides the second support for the table. In any event, leg structure  6  includes an upper tubular structure or tube  10 , a first leg section  11 , a second leg section  12 , a footpad  13 , and, in the preferred embodiment, a pair of wheels  14 . 
     The tube  10  is a cylindrical structure adapted to receive and mount the first leg section  11 . In the embodiment illustrated, each single tubular structure  10  is adapted to receive and mount two of the upper leg sections  1   1 . Attachment between the leg section  11  and the tube  10  may be accomplished in any convenient method. 
     Referring now to FIG. 3, it may be observed that each of the beams  5  and  5 ′ is generally L shaped in side elevation, the L being defined by a leg  20  and a leg  21 . The leg  21  is positioned so it abuts the lower side  4  of the table  2 , and is attached thereto by any convenient method. Epoxy adhesive or conventional threaded fasteners, for example, are used in the art. The tube  10  is sized to be positioned between the legs  20  of each of the beams  5  and  5 ′, as best observed in FIG.  3 . 
     Each tube  10  has at least one axle  25  associated with it, which extends outwardly along each of the opposite ends of the tube  10 . While described as a single axle, those skilled in the art will appreciate that in fact the axle may be separated. That is to say, the axle  25  need not be continuous through the tube  10 . Rather, a pair of individual axle sections may be mounted along each end of the tube. Axle  25 , whether a single and or multiple parts, is used to mount the wheels  30  and  31  of wheel pair  14  along the opposite sides of the tube  10 . Also mounted along the axle  10 , inboard of the respective wheels, is a link  40 . Link  40  may assume a variety of shapes in various embodiments of the invention. Here it is sufficient to note that the link  40  extends between the leg structure, and one of the beams  5  and  5 ′. Again, in the embodiment illustrated, each end of the tube  10  has a link  40  associated with it. Each of the links  40  is attached to its respective beam  5  or  5 ′. 
     Each of the beams  5  and  5 ′ also has a notch or receptacle  56  formed in it, which is sized to receive the axle  25  in the table supporting position of the leg structure, as later described in greater detail. 
     A support arm  57  extends between each of the leg sections  11 . The support arm  57  has a pair of struts  58  associated with it. The struts  58  extend between the arm  57  and respective one of the beams  5  and  5 ′. The struts  58  are rotationally mounted about an axis  60  associated with the respective beams  5  and  5 ′, an axis  61  associated with the leg sections  11 , and a pivot point  62  associated with the link  40 . 
     As indicated above, the leg section  11  and  12  preferably are telescopically mounted one within the other. A series of adjustment openings  70  are provided along one side of the leg section  11 . The leg section  12  carries a spring loaded plunger  39  which enables one to move the part  12  with respect to the part  11  along the openings  70  to adjust the height of the table, the plunger  39  extending through the selected opening  70  to maintain the desired table height. 
     Footpads  13  are conventional and may comprise any of a variety of designs for providing support to the legs. 
     Referring now to FIGS. 2 and 3, the extended and stored positions of the leg structure are illustrated. In the extended position of the leg structure, the wheels  30  and  31  are positioned very near the underside of the tabletop  3 , and, as is observable in FIG. 1, often invisible to a user of the table. In the extended or operative position of the legs, the axle  25  is received in the notch  56  of the beams  5  and  5 ′ in a conventional manner. Although not shown in the drawings, those skilled in the art will appreciate that a conventional locking mechanism may be employed to retain the axle locked in the notch  56 , keeping leg in its table supporting position and preventing inadvertent collapsing of the leg. However, when movement or storage of the table is desired, any latching mechanism, if employed, is released and the leg structure  6  merely is rotated towards the fold up position shown in FIG.  3 . As the leg rotates, the link and wheel inscribe a movement arc  75 , which permits the leg structure to fold, while simultaneously moving the wheels  30 ,  31  from their position adjacent the underside of the table  1  to a position relatively outboard with respect to that top. Thereafter, either end of the table merely is lifted, and the table wheeled along the opposite wheel set, in what we have described above as wheelbarrow fashion, to move the table  1  to a new location or to storage, for example. 
     Numerous variations, within the scope of the appended claims, will be apparent to those skilled in the art in light of the following description of the accompanying drawings. While preferably, the legs are height adjustable, the leg structures may be single height, if desired. As indicated, the particular design of the legs may be altered. We have found it particularly convenient to employ what resembles a “K” design to the legs. This permits or gives a user in certain situations greater access to the length of the table without running above of the associated leg structure. In computer training room situations, for example, associated wire management devices may be employed with the table, if desired. Alternate designs for attaching the strut between the leg structures and the table may be utilized, if desired. These variations are merely illustrative.