Abstract:
A foldable, portable step stool constructed of at least one flat planar surface, or platform that can be combined with a vehicle used to transport a load. The flat planar surfaces are connected by foldable joints and folded against each other for storage in the space between the storage area and the wheel base of the vehicle. The flat planar surfaces are unfolded to create one unified surface, the platform of the step stool. The platform is supported by legs connected to the underside of one or more of the flat planar surfaces. The legs are situated to be out of the way when the step stool is folded. Within each leg is a spring mounted wheel caster mechanism that retracts into the leg when weight is applied to the stool in its deployed position. Non-slip pads also prevent the legs from moving in the deployed position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     Not applicable.  
       FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not applicable.  
       SEQUENTIAL LISTING  
       [0003]     Not applicable.  
       BACKGROUND OF THE INVENTION  
       [0004]     1. Field of the Invention  
         [0005]     This invention is related to the field of devices utilizing a supported planar surface or surfaces (“platform” or “platforms”) in combination with devices or structures having another function. It is a step stool constructed in a manner such that it can be portably combined with a vehicle used to transport a load, such as a shopping cart. In other embodiments, it is the apparatus combining a shopping cart and step stool.  
         [0006]     2. Description of the Related Art  
         [0007]     Vehicles used to transport a load, such as a shopping cart employing a basket mounted on a wheeled base, are utilized extensively in supermarkets, department stores and the like. In the form of a shopping cart, they are generally constructed of a plurality of metal or plastic wire and tubular members and joint fittings, but can be constructed of a multitude of materials and in a multitude of styles. For example, the cart could be made entirely of wood or fiberglass, and the basket could be an enclosed box, or it could be a shallow tray. The base generally will ride on three or four wheels, with at least the front wheels attached to the base as part of a caster assembly on a pivoting shaft so that they can be turned by the user with the application of a small angled force on the handgrip. The rear wheels may be similarly pivotable for added maneuverability but this is not necessary.  
         [0008]     The handgrip will generally be positioned so that it is slightly raised above the rear end of the basket, and will be attached thereto by a structure connecting the handgrip and basket with the base. The handgrip is generally perpendicular to the center line of the cart, the center line being characterized as the line from the back to the front of the cart also representing the direction of travel. Shopping cart technology is a well developed field, extensive and varied. For example, U.S. Pat. No. 2,479,530 to Watson (1949), U.S. Pat. No. 2,556,532 to Goldman (1951), U.S. Pat. No. 2,590,285 to Wiltshire (1952), U.S. Pat. No. 2,596,775 to Kasper (1952), U.S. Pat. No. 3,614,133 to Ganci (1971), U.S. Pat. No. 3,999,774 to Rehrig (1976), and U.S. Pat. No. 6,488,292 to O&#39;Quin (2002).  
         [0009]     Similarly, step stools are common. In its simplest form a step stool will consist of a flat surface supported by three or four legs connected to the bottom of the flat surface. The top of the flat surface can be bare, or covered with a textured or contoured surface for comfort or grip. The stool can be used for sitting or standing, in either case giving the user more elevation than would otherwise be available. A step stool is generally considered to be a stool small enough in size and low enough to the ground to be easily ascended in one step. As such, it is generally used to functionally increase the height of the user by the equivalent of the height of the step. While there is no specific height limitation or requirement, a step stool could generally be expected to range between 6 and 18 inches (between 15 and 45 centimeters) in height. A step stool can have more than one step, the principle remaining the same, but with each step ascended increasing the overall height of the user. A step ladder would follow the same concept, but would necessarily have several steps ascending in height while a step stool can have one or more than one step. As step ladders are larger, they are often foldable so that they are more conveniently transported and stored.  
         [0010]     Step ladders and step stools being low-tech, easy to use, and very utilitarian, they have been developed extensively in combination with other devices. This includes devices for which the primary use is transporting a load. For example, see U.S. Pat. No. 6,158,749 to Roudebush (2000) and U.S. Pat. No. 4,235,449 to Tarran (1980). These two patents are to a step stool and dolly apparatus (Roudebush) and a combined hand truck and step stool (Tarran), respectively.  
         [0011]     Roudebush discloses a folding step stool that is convertible into a hand truck, apparently using the words hand truck and dolly interchangeably. The Roudebush apparatus has two steps in its stool configuration and the entire apparatus folds substantially flat for storage. In its dolly configuration, it has a bottom pivotable dolly unit that is coupled to the front frame member. The load to be carried can thus be placed on the dolly and the apparatus tilted to free the wheels for rolling the apparatus and load. This apparatus can be used only to transport certain types of load. This would include large, heavy, single items within the size and weight range that can be manipulated by a person. For example, large boxes of warehoused items. Smaller items would tend to slip off and would not be worth the trouble of positioning on the dolly. Multiple items would be untenable except for the limited ability to stack them vertically, single file, one on top of another, but this would still be limited by the ability of the user to balance the items during transit. The step stool in the Roudebush apparatus cannot be used simultaneously with the dolly apparatus. The dolly and the step stool are mutually exclusive configurations. The hand truck and step stool configurations are likewise mutually exclusive in the Tarran apparatus. In terms of its function, and in every way relevant to the present application, Tarran is similar to Roudebush.  
         [0012]     The apparatus of the present invention allows use as both a step stool and shopping cart simultaneously. In fact, its greatest utility is that it is can be used as both items at the same time. Of course, it can also be used as a shopping cart or step stool alone should that suit the needs of the user. Its utility as a vehicle used to transport a load has the same advantages over a dolly that would be evidenced by a comparison between any standard dolly and any standard shopping cart. It can be used to carry many items simultaneously without the need to stack the items and balance them precisely, and it can be used to carry as heavy a single item as the user can lift into the basket alone or assisted. The net maximum load that can be so transported is at least as heavy as that which can be carried by the dolly, being limited only by the dimensions of the particular basket (which can be varied at time of construction) and the maximum load that can be pushed by the user.  
         [0013]     Its utility as a step stool is greatly enhanced by its particular portability between the basket and base of a shopping cart. Thus it will be automatically transported wherever the shopping cart goes, and the user can fold it out and use it to gain extended reach height at the user&#39;s convenience.  
       BRIEF SUMMARY OF THE INVENTION  
       [0014]     The step stool can be mounted on the base of a shopping cart such that it can be folded or flipped into the space between the base and basket of the cart for easy storage and transport. It can be mounted on the front or back of the cart, with the preferred embodiment attached to the front of the cart. When deployed (unfolded or unflipped) onto a floor surface, it will provide additional extended reach height when stepped upon by a person.  
         [0015]     The height of the step stool can correspond to the storage space available between the basket and base of the respective shopping cart design model. The stool can be mounted manually with hinges. Spring-loaded retractable wheels are enclosed within the legs. These wheels compress upon application of a downward force, as would result from a person stepping on the stool, with the result being that the wheels retract within the legs, leaving the surrounding legs to grip the floor surface. When weight is not being applied, the wheels thus extend outward beneath the legs, allowing the stool to be rolled along with the cart in its open position.  
         [0016]     It can be made of stainless steel, plastic, or any other material of sufficient strength to support the weight of a person. It would likely be most convenient to construct the step stool out of the same material as the shopping cart. The shopping cart also can be constructed of a wide range of materials. Additional features of the present invention will become apparent to those skilled in the art upon consideration of the claims and the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0017]      FIGS. 1A through 1C  are profile views of the preferred embodiment.  FIG. 1A  shows the invention with the step stool in flipped, or stored, position.  FIG. 1B  shows the invention with the step stool in its deployed position (unfolded, or unflipped).  FIG. 1C  shows the invention in use.  
         [0018]      FIG. 2  is a perspective view of the step stool only, with an exploded view of the hinge. The dashed line represents the part of the base of the cart to which the hinge connects.  
         [0019]      FIGS. 3A and 3B  show a cut away view of a leg of the step stool with the inner wheel mechanism exposed.  FIG. 3A  shows the leg with the wheel retracted upon the application of a downward force (a weight on the stool).  FIG. 3B  shows the wheel in its unforced state (extended from the bottom of the leg).  
         [0020]      FIGS. 4A through 4C  show another embodiment of the stool, with a two part hinged platform.  FIG. 4A  shows the stool in closed, folded position.  FIG. 4B  shows it midway through unfolding.  4 C shows the stool completely unfolded.  
         [0021]      FIG. 5  shows a detachable embodiment of the stool attachment with a one part platform and a curved screwless hinge.  
         [0022]      FIG. 6  shows the same embodiment as  FIG. 5 , attached to the base of a shopping cart.  
         [0023]      FIG. 7  shows the relative dimensions of various parts of the apparatus.  
     
    
     REFERENCE NUMERALS IN DRAWINGS  
       [0000]    
       
           10  Underside of stool platform  
           11  Top side of stool platform  
           12  Stool platform  
           13  Front section of two part stool platform  
           14  Joint of Hinge  46  Attaching Platform to wheel base  
           15  Back section of two part stool platform  
           16  Front bar of shopping cart wheel base  
           17  bottom front edge of shopping cart basket  
           18  Slide resistant floor pad  
           19  Stud  
           20  Wheel caster mechanism  
           21  Wheel inside stool leg  
           22  Bottom of shopping cart basket  
           23  Spring  
           24  Top of shopping cart wheel base  
           25  Mounting bolt  
           26  Bottom of shopping cart wheel base  
           27  Strut inside stool leg  
           28  Back bar of shopping cart wheel base  
           29  Washer, nut, or o-ring  
           30  Strut attaching front wheel to wheel base  
           31  Shopping cart wheel base  
           32  Shopping cart front wheel  
           34  Strut attaching rear wheel to wheel base  
           36  Rear wheel of shopping cart  
           38  Basket  
           40  Shopping cart basket support and hand grip  
           42  Stool leg  
           43  Stool leg  
           44  Textured surface of platform  
           45  Hinge of two part platform  
           46  Hinge connecting stool to wheel base  
           47  Curved member for attachment to wheel base  
           48  Bolt or screw securing hinge to wheel base  
           49  Nut or washer securing  48   
       
     
       DETAILED DESCRIPTION OF THE INVENTION  
       [0059]     In its preferred embodiment, shown in  FIGS. 1 through 3  and  7 , this invention is a shopping cart  38  with basket  22  and four wheels  36  and  32  (two shown) on a wheel base  31 , and a step stool with a solid one part platform  12  mounted on the front end of the wheel base  16  with a hinge  14  fixed in place by screws or bolts secured by washers or nuts. This embodiment is preferred due to its simplicity rather than any additional functionality over other embodiments.  FIG. 1A  shows a profile view of this embodiment with the step stool in retracted, folded, or flipped position.  
         [0060]      FIG. 1B  shows the embodiment in its deployed, unflipped or unfolded position. Essentially, flipped or folded is the storage position, with the stool between the top of the wheel base  24  and basket  22  of the shopping cart  38 . The step stool is used in its deployed, unflipped or unfolded position. A step stool in accordance with this invention will have a platform  12 . The platform  12  in the preferred embodiment is comprised of only one solid flat piece. Two legs  42  with internal wheel casters  20  are attached to the underside of the platform  10 . The bottom of each leg is capped with a slide resistant pad  18 .  
         [0061]      FIG. 2  shows a close-up view of the stool with an exploded view of the connection between stool platform  12  and wheel base  31 . The hinge  14  connects the stool platform  12  to the shopping cart wheel base  31  with screws or bolts  48  inserted through the hinge  14  and secured by nuts or washers  50 . The hinge  14  includes a flange  46  that is flat where it extends out from the joint in the hinge, but curved around the wheel base  31  to fit securely. The flange  46  includes holes in both the portion that passes across the top of the wheel base  31  and the portion that curves beneath the wheel base  31  so that each bolt  48  passes through the flange  46  twice.  
         [0062]     The dimensions of the step stool are shown in  FIG. 7  and determined by the requirement that the stool fit the intended shopping cart. The distance from the top of the platform  11  to the bottom of the pad  18  on each leg  42  should be about the same as the distance from the top of the wheel base  24  to the bottom of the front wheel  32 . This is shown in  FIG. 7  as distance “a.” The distance from the hinge joint  14  to the forward bottom edge of the pad  18 , “c” in  FIG. 7 , can be no larger than the closest approach distance from the hinge joint  14  to the bottom front edge of the shopping cart basket  17 . In order to guarantee maximum compatibility of the stool without regard to the exact dimensions of the basket  38  relative to the wheel base  31 , the length of the stool from front to back “b” should be less than the distance from the top of the wheel base  24  to the bottom of the basket  22 , “h” in  FIG. 7 .  
         [0063]      FIGS. 3A and 3B  are cut away views of a leg of the stool  42 , showing its inner wheel caster mechanism  20 . Inside each leg  42  is a wheel caster mechanism  20 . The individual stool legs are identical. The description of the mechanism  20  mounted within each leg is the same. The mechanism is affixed to the inside of the leg  42  by a wheel mounting bolt  25 . A washer or nut or o-ring  29  holds the mounting bolt  25  in place. The washer  29  is solidly affixed to the inside of the leg  42 . The bolt  25  is affixed within the leg  42  in such a way that it is permitted a certain amount of vertical movement but is unable to pass completely through the washer  29 . At its top, the bolt  25  is held above the washer by a stud or other protrusion  19 . A strut  27  is attached to the base of each bolt  25 . A wheel  21  is attached within each strut  27  and is braced and held in place by the strut  27 . A spring  23  is placed around the mounting bolt  25  above the strut  27 . The spring  23  is restricted above by the washer or o-ring  29 . The washer  29  completely encircles the mounting bolt  25  so that the spring is confined between the strut  27  and the washer  29 .  
         [0064]     The embodiment in  FIGS. 1 through 3  and  7  operates as any shopping cart would, with the exception that it carries with it a step stool stored in part of the space between the top of the wheel base  24  and the bottom of the basket of the cart  22 . When the person using the device needs to use the stool, it can be flipped into position by merely grabbing one of the legs  42 , or the platform  12  and pulling upward and/or outward so that the entire stool turns on its hinges  14 . The stool is turned (deployed or unflipped) until the slide resistant floor pads  18  on the bottom of each leg  42  are flush with the floor. The top of the platform  11  will then be parallel with the floor, and the user can stand on it, or sit on it, or use it for any other purpose suitable for a stool. The top of the platform  11  may include a textured surface  44  or other added surface element to increase friction and prevent sliding.  
         [0065]     The wheel caster mechanism  20  within each leg  42  of the stool allows the stool to roll on the floor along with the rest of the shopping cart as long as no downward weight is applied to the top of the stool. The spring  23  on the mounting bolt  25  within each mechanism  20  provides a persistent force tending to keep the wheel  21  clear of the bottom of the floor pad  18  at the bottom of each leg  42 . Thus the wheel  21  remains free to roll provided no weight is on the stool. When a weight is applied to the top of the stool the spring  23  contracts, causing with wheel  21  to withdraw into the leg  42  of the stool until virtually all of the weight on the stool is supported by the floor pad  18  at the foot of each leg  42 . In this manner, the stool is held in place when weight is applied, but can roll along with the cart when no weight is applied to the stool.  
         [0066]     FIGS.  4 A-C show another embodiment of the invention. In this embodiment, the step stool platform is a two part affair. The front section of the platform  13  is connected to the back section of the platform  15  with a hinge or other folding joint  45 . The back of the platform  15  then connects with the wheel base  31  by way of the same type hinge  46  that connects the platform in the earlier embodiment.  
         [0067]     Each leg  43  of this embodiment is attached to the front section of the platform  13  in a manner such that the leg drops off to the left or right side of the platform respectively, so that the legs will fit out of the way when the stool is folded. In this particular representation of this embodiment, the bend in each leg is slightly more pronounced than in the preferred embodiment, with the part connected to the underside of platform  13  extending laterally outward slightly further in order to facilitate the leg fitting around the wheel base  31  when the stool is folded. In other respects each leg  43  is the same as each leg  42  in the earlier embodiment, with floor pad  18  and wheel mechanism  20 . There is quite a bit of leeway regarding the exact shape of each leg in either embodiment, and it would be possible for the same leg to be used in either. The preferred embodiment has more leeway in this matter, as the legs do not need to fit around any other part when the stool is folded.  
         [0068]     The embodiment shown in FIGS.  4 A-C operates as the previous embodiment by providing a step stool stored between the wheel base  31  and basket  38 . The hinge  45  in the platform  12  allows the front of the platform  13  to fold against the back of the platform  15  so that the bottom of each part rests against the bottom of the other. This is shown in  FIG. 4B . The folded stool is then stored when the back of the platform  15  flips over the wheel base  31  using hinge  46  in the same manner as accomplished in the earlier embodiment. This is shown in  FIG. 4A . The different positioning of the legs  43  in this embodiment allows them to easily fit alongside the wheelbase  31  when the stool is folded and stored. The two part platform can thus be stored in a smaller area than would otherwise be possible for the same size stool if the platform were one piece. By allowing for the platform to fold for storage, therefore, the embodiment shown in FIGS.  4 A-C can also accommodate a larger total stool platform  12  when the stool is completely unfolded than would be possible in the earlier, simpler preferred embodiment.  
         [0069]      FIGS. 5 and 6  show another embodiment of this invention. While its platform and legs and the parts thereof are similar to the preferred embodiment in other ways, in this embodiment the shopping cart step stool platform  12  includes a curved screwless hinge or hooking member at the back  47 . This is in lieu of the hinge  46  and joint  14  in the preferred embodiment. Said curved member  47  extends across the entire width of the stool platform  12  and is fitted to be readily attachable to the wheel base  31  of a shopping cart.  
         [0070]     This embodiment can be carried separately from the cart and attached to the wheel base when needed.  
         [0071]     The novel utility of the embodiments of this device are distinct from the normal utilities that would be expected from a shopping cart or step stool alone. This device provides an always present readily available step stool. Since the stool is portably transported along with the shopping cart it is always at hand when needed, whenever the shopping cart is in use, with no additional requirement to remember to bring it along. The stool can be quickly unfolded and used to access elevated objects with minimal effort, then just as easily stored and forgotten, yet it will always be thoughtlessly and effortlessly present whenever it is needed.  
         [0072]     Although the invention has been described above in detail with reference to certain preferred embodiments and the description contains many specifics, these should not be construed as limiting the scope of the invention. They merely provide illustrations of some of the presently preferred embodiments of this invention. Variations and modifications exist within the scope and spirit of the invention as described and as defined in the following claims. Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the given examples.