Abstract:
A wheel assembly and a method of using the wheel assembly are provided. The wheel assembly is attachable to various objects and capable of quickly and easily collapsing or folding to become more compact for more efficient and cost-effective transportation or shipping. It is then capable of being quickly and easily expanded.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 11/590,279, filed Oct. 30, 2006, which is incorporated by reference as if fully set forth. 
    
    
     FIELD OF INVENTION 
     The present invention is in the field of wheel assemblies for transporting products. More particularly, the invention is directed to a wheel assembly that is capable of quickly and easily collapsing or folding and thus, becoming more compact for more efficient and cost-effective transportation or shipping. 
     BACKGROUND 
     Wheel assemblies are secured to various types of products to allow the products to be more easily and conveniently transported. Wheeling is generally a more effective means of transporting a product than other means such as carrying, especially when the product is large or heavy. Many wheel assemblies include a rigid base, an axle fixed to the base and wheels positioned along the axle. The axle is rigid; often a single steel bar or stub axles welded or rigidly fixed on opposite sides of the product. The wheels are generally located at fixed positions along the axle; typically at the axle&#39;s opposite ends. The axle and wheels must extend sufficiently beyond the product&#39;s boundaries to provide a stable base and be sufficiently designed to support a heavy load when the product is wheeled. 
     The known axle-wheel arrangement typically makes the product larger and heavier, and therefore, more costly for the manufacturer or distributor to package and transport. To reduce size for shipping, wheel assemblies are often completely removed before shipping, shipped separately, and then reattached when the product and wheel assemblies arrive. This is time consuming, costly and sometimes, detaching and reattaching the wheel assembly damages the product. Even if it is desirable to detach and reattach the wheel assembly, it is still adds cost and expense. 
     There is a need for a cost-effective wheel assembly that can be used in connection with products designed to support large and/or heavy loads and that can be quickly and easily transformed to a more compact arrangement for packaging, shipping or transporting both while attached to the product or when detached. There is also a need for a wheel assembly that can be quickly and easily expanded, from the compact arrangement to a use position, as necessary, to efficiently wheel the product, for example, when the product reaches its final destination. 
     SUMMARY 
     The present invention is directed to a collapsible wheel assembly comprising: a base; a plurality of wheels; a plurality of axles having opposite first and second ends, each of the axles pivotally connected to a fixed member on the base and movable within a defined plane; and each of the axles having at least one of the wheels located thereon such that the wheels are respectively slideable along a respective one of the axles. 
     In another embodiment, present invention provides a wheel assembly convertible between an expanded state and a collapsed state, comprising: a fixed member; a plurality of axles having first and second ends, each of the second ends being pivotally connected to the fixed member; a plurality of wheels, each wheel mounted on a respective axle and slideable along a length of the axle. In the expanded state, each wheel is located at a first distance from the first end of the axle, and in the collapsed state, each wheel is located at a second distance that is greater than the first distance, from the first end of the axle. 
     The present invention also provides a method of using the aforementioned collapsible wheel assemblies, with the method comprising: collapsing the collapsible wheel assembly by rotating the axles about the pivotal connections away from the base; sliding the wheels along a length of the axles in a direction from the first end towards the second end of each axle. With the wheels collapsed, the wheel assembly is more compact allowing it and the object to which it is attached to be transported or shipped in a more compact package, reducing cost. 
     The wheel assembly is easily expanded by pulling the wheels toward the first ends of the respective shafts and rotating the axles toward the base. The base is easily attachable to, and capable of supporting and allowing easy transport of many different objects, and is of particular use in connection with large, movable heaters and fans. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing summary, as well as the following detailed description of the preferred embodiments of the invention will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangement shown. 
         FIG. 1  is a perspective view of an embodiment of the wheel assembly of the present invention in the first or expanded use position. 
         FIG. 2  is a side plan view of the wheel assembly shown in  FIG. 1  with the wheels removed. 
         FIG. 3  is an enlarged top plan view of the base of the wheel assembly shown in  FIG. 1 . 
         FIG. 4  is a perspective view of the wheel assembly shown in  FIG. 1  secured to an object. 
         FIG. 5  is a perspective view of the wheel assembly shown in  FIG. 1  in between the first or expanded use position and the second or folded position. 
         FIG. 6  is a perspective view of the wheel assembly shown in  FIG. 1  in the second or folded position. 
         FIG. 7  is a perspective view of another embodiment of the wheel assembly of the present invention in the second or folded position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1-6  show a preferred embodiment of a collapsible wheel assembly  10  of the present invention. The assembly  10  is comprised of a base  12 , two shafts or axles  14  and two wheels  16 . The base  12  is preferably rigid and comprised of metal such as steel or aluminum, or may be made of any other suitable material, such as a rigid composite of polymeric material. The axles  14  are also rigid, and are preferably comprised of steel or another suitable metal. The wheels  16  are comprised of a hub  15  surrounded by tires  17 , which are preferably rubber but may be polymeric. 
     As shown in detail in  FIGS. 1 and 6 , the axles  14  each include a first end  18  and an oppositely-located second end  20  and extend through the wheel hubs  15 . In the expanded position, shown in  FIG. 1 , the wheels  16  are located at the respective first ends  18  of the associated axles  14 . As shown in detail in  FIGS. 5 and 6 , wheel pins  22 , which may be a cotter pin or hair pin cotter other suitable pin inserted through a hole in the first ends  18  of the axles  14 , prevent the wheel hubs  15  from sliding off of the axles  14 . The wheels  16  are free to rotate on the axles  14  allowing the wheel assembly  10  to roll backward and forward. The wheels  16  are also slideable along the axles  14 . 
     As shown in  FIG. 1 , mechanical interference between the wheel hubs  15  and flanges  13  on opposite first and second ends  19 ,  20  of the base  12  keep the wheels  16  from sliding inward; i.e., toward the second ends  20  of the axles  14 . As shown in detail in  FIG. 2 , within each of the two the flanges  13  is a slot  34 . These slots  34  are slightly larger than the diameter of the axles  14  but have protrusions  38  that extend within the slots  34  and mechanically interfere with the axles  14  when the assembly  10  is in the first or expanded position. Frictional force between the protrusions  38  and the axles  14  keeps the axles  14  snugly within the slots  34 , which keeps the axles  14  in the expanded position. The fit is snug enough such that the axles  14  do not release from the grooves  34  unless forced out by a user. When an object  24  is wheeled on the assembly  10 , as shown in  FIG. 4 , the weight of the object on the wheel assembly  10  also keeps the axles  14  in the expanded position. 
     As shown in  FIG. 2 , the base  12  comprises a first or top face  26  and an oppositely located second or bottom face  28 . As shown in  FIG. 4 , the top face  26  is secured to a product or object  24 . As shown in  FIGS. 1 and 4 , the base preferably includes at least one slot or hole  36  and can be secured to the object by bolts, or screws through the object and the top face  26  of the base  12 . Alternatively, the object  24  may be secured to the base  12  by welds, or by springs or clamps engaging with the object and the base  12 . Alternatively, the top face  26  may include a groove or channel and the object  24  fits snugly within the groove or channel and is held to the top face  26  by friction between the object  24  and the walls of the groove or channel. Alternatively, the object  24  and the base  12  are formed as one piece. 
     As shown in  FIGS. 1 and 3 , the second ends  20  of the axles  14  are pivotally connected to the bottom face  28  of the base  12 , preferably, near the center of the base  12 . As shown in detail in  FIG. 3 , the bottom face  28  of the base  12  comprises brackets  30  that are welded to the bottom face  28  of the base  12  or formed from the material of the base  12  in a punching or stamping operation. The second ends  20  of the axles  14  are preferably offset and fit within these swivel brackets  30 . A bolt or pin  32 , is inserted through the swivel brackets  30  and holes  23  in the axles  14 . This secures the axles  14  within the brackets  30  and, as shown in  FIG. 5 , and allows the axles  14  to rotate  180  degrees in either direction about the bolt or pin  32  between the first, expanded position of  FIG. 1  to the second, folded position of  FIG. 6 . One skilled in the art would recognize that other types of pivot assemblies may be used to allow the axles  14  to rotate; such as a hinge or other pivot. 
     The wheel assembly  10  is capable of collapsing from the first or expanded position, shown in  FIG. 1  to the second or folded position, shown in  FIG. 6  as follows. A user (not shown) disengages the axles  14  from the protrusions  38  by pressing the axles  14  upwardly and out from within the slots  34 . The user then rotates the axles  14  toward each other; i.e., away from the bottom face  28  of the base  12 . This position is shown in  FIG. 5 . The user then slides the wheels  16  along the axles  14  toward each other, or allows the wheels  16  to slide toward each other under the force of gravity, until the wheels  16  touch. The second or folded position is shown in  FIG. 6 . It is more compact than the first or expanded position, which allows the assembly  10  and product  24  that is attached to be shipped or transported more easily and cheaply. 
     The mechanical interference from the wheels  16  against each other and the bottom face  28  of the base  12 , keeps the wheel assembly  10  in the folded position. Alternatively, the wheel assembly  10  comprises a mechanism (not shown) that locks the wheels  16  in the position shown in  FIG. 6 . In yet another embodiment, there are hinges (not shown) along the axles  14 ; preferably, half-way along the axles  14 , that are capable of locking when the wheel assembly  10  is in the first position but allow a portion of the axles  14  to be folded downward; i.e., rotated toward the tires  17  in the second, folded position. In other words, the portions of the axles  14  extending from the wheels  16 , shown in  FIG. 6 , can be folded downward. 
     To expand the wheel assembly  10  from the folded position to the expanded position, the user simply slides the wheels  16  toward the first ends  18  of the axles  14  ( FIG. 5 ) and rotates the axles  14  toward the bottom face  28  of the base  12  and presses the axles  14  between the protrusions  38  in the grooves  34 . Thus, the wheel assembly  10  can be quickly and easily folded and unfolded. 
     Even though the figures show the wheel assembly  10  changed from the expanded to the folded position and vice-versa when detached from the object  24  ( FIGS. 1 ,  5  and  6 ) that is wheeled, it should be obvious to one skilled in the art that the wheel assembly  10  may be easily folded or expanded as described above, while attached to the wheeled object  24  ( FIG. 4 ). 
     In another embodiment, not shown, there are multiple wheels on each axle. In another embodiment, not shown, more than two (2) axles can be provided, for example, by using two of the assemblies  10  which may include or a combined base. 
       FIG. 7  shows another embodiment of the wheel assembly  40  in the folded position. The axles  14  are spaced apart such that the wheels  16  do not contact each other in the folded position. In this embodiment, the axles  14  are shorter and are located adjacent the ends  42 ,  44  of the base  46  and pivot via brackets  48  to a ninety-degree (90°) position and the wheels  16  slide toward the base  46  until the wheels  16  rest flat against the base  12 . Thus, when in the assembly  40  is in the folded position, shown in  FIG. 7 , the wheels  16  are flat on the base  12  and do not contact each other. 
     Having thus described in detail a preferred selection of embodiments of the present invention, it is to be appreciated and will be apparent to those skilled in the art that many physical changes could be made in the apparatus without altering the inventive concepts and principles embodied therein. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore to be embraced therein.