Abstract:
A shopping cart includes front and rear casters, a frame supported by the front and rear casters, a tray attached to the frame and a lifting structure arranged on the tray and configured to elevate rear casters of a preceding cart upon engaging thereto. The lifting structure includes a first portion configured to elevate the rear casters of the preceding cart upon engaging thereto, a second portion adjoining the first portion and maintaining the rear casters of the preceding cart elevated upon engaging thereto, and a third portion located between the first portion and the second portion and configured to resist the preceding cart from sliding off the shopping cart.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. §119(e) to provisional U.S. Patent Application No. 60/730,360, filed on Oct. 27, 2005, the disclosure of which is expressly incorporated by reference herein in its entirety. 
     
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention is directed to carts, particularly to shopping carts with a structure for reducing damage to casters and improving lateral maneuverability during the transportation thereof. 
         [0004]    2. Related Art 
         [0005]    Shopping carts generally include four sets of casters with two casters in the front and two casters in the rear of the cart. Typically, the two front casters are configured to rotate about a vertical axis whereas the rear set of casters are configured not to rotate about the vertical axis. Such an arrangement does not cause any problems for individual shoppers. However, when multiple shopping carts are nested together and transported from one particular area to another particular area, such as a parking lot area to the front of the store, then the non-swiveling rear casters may be damaged during such transportation. In particular, during the process of transporting the carts, there will tend to be a need to steer the carts to change direction of the line of nested carts. This steering movement may not cause any significant problems for the front casters that are able to swivel, but the rear casters will have to slide or be dragged across the ground, in order to achieve the steering movement. In this regard, this lateral dragging of the rear casters will cause the rear casters and/or the cart to be damaged. Moreover, the need for dragging the rear casters reduces maneuverability of the shopping carts. 
         [0006]    Accordingly, there is a need for reducing damage to the rear casters of the cart and for increasing lateral maneuverability during the transportation thereof. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention meets the foregoing needs and provides a method and apparatus that lifts the rear casters of a shopping cart to avoid or reduce damage caused by at least lateral movement of the shopping cart and increases maneuverability while limiting stress to the shopping cart and that furthermore includes other advantages apparent from the discussion herein. 
         [0008]    Accordingly, in one aspect of the invention a shopping cart includes front and rear casters, a frame supported by the front and rear casters, a tray attached to the frame, and a lifting structure arranged on the tray and configured to elevate rear casters of a preceding cart upon engaging thereto. The lifting structure may include the first portion configured to elevate the rear casters of the preceding cart upon engaging thereto, the second portion adjoining the first portion and maintaining the rear casters of the preceding cart to be elevated upon engaging thereto, and the third portion located between the first portion and the second portion and configured to resist the preceding cart from sliding off from the shopping cart. 
         [0009]    According to another aspect of the invention, a lifting structure for a shopping cart includes a ramp portion arranged on an upper surface of the lifting structure configured to elevate rear casters of a preceding cart upon engaging thereto, a lift portion arranged on the upper surface of the lifting structure configured to maintain the rear casters of the preceding cart to be elevated upon engaging thereto, and a lip portion arranged between the ramp portion and the lift portion on the upper surface the lifting structure and configured to resist the preceding cart from sliding off from the shopping cart. 
         [0010]    Additional features, advantages, and embodiments of the invention may be set forth or apparent from consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that both the foregoing summary of the invention and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0011]    The accompanying drawings, which are included to provide a further understanding of the invention, are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the detailed description serve to explain the principles of the invention. No attempt is made to show structural details of the invention in more detail than may be necessary for a fundamental understanding of the invention and the various ways in which it may be practiced. In the drawings: 
           [0012]      FIG. 1  illustrates a shopping cart with a lifting structure, constructed according to the principles of the invention; 
           [0013]      FIG. 2  shows details of the tray of the shopping cart shown in  FIG. 1 ; 
           [0014]      FIG. 3  shows details of an exemplary lifting device arranged on the tray of  FIG. 1 ; 
           [0015]      FIG. 4  shows a side view of the shopping cart shown in  FIG. 1 ; 
           [0016]      FIG. 5  shows a side view of two shopping carts nested together according to the principles of the invention; 
           [0017]      FIG. 6  shows a perspective view of the trays of the two shopping carts shown in  FIG. 5  nested together; 
           [0018]      FIG. 7  shows three shopping carts nested together according to the principles of the invention; 
           [0019]      FIG. 8  shows a bottom view of the lifting structure shown in  FIG. 3  constructed according to the principles of the invention; and 
           [0020]      FIG. 9  shows another embodiment of a lifting structure constructed according to the principles of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    The embodiments of the invention and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments and examples that are described and/or illustrated in the accompanying drawings and detailed in the following description. It should be noted that the features illustrated in the drawings are not necessarily drawn to scale, and features of one embodiment may be employed with other embodiments as the skilled artisan would recognize, even if not explicitly stated herein. Descriptions of well-known components and processing techniques may be omitted so as to not unnecessarily obscure the embodiments of the invention. The examples used herein are intended merely to facilitate an understanding of ways in which the invention may be practiced and to further enable those of skill in the art to practice the embodiments of the invention. Accordingly, the examples and embodiments herein should not be construed as limiting the scope of the invention, which is defined solely by the appended claims and applicable law. Moreover, it is noted that like reference numerals represent similar parts throughout the several views of the drawings. 
         [0022]    With reference to  FIGS. 1 and 2 , a cart  100 , such as a shopping cart, may be constructed with components that are commonly used in conventional carts, such as a basket  102 , a frame (e.g., chassis)  104 , a tray  106 , rear casters  110 , front casters  120 , and a handle  124 . The basket  102  may be used to hold groceries or other items that a shopper might desire to purchase while shopping. The basket  102  of the cart  100  may be formed of a plastic material that is molded, may have a welded metallic construction that is painted or powder coated, or have any other known construction. The cart  100  may also include the handle  124  to guide the cart  100  through the shopping process and may also include an area  126  for small children to sit, mount a baby carrier, or load small or delicate items. The tray  106 , which may be used to carry larger items or overflow items from the basket  102 , may be positioned just above the casters  110 ,  120  and below the basket  102 . The cart  100  also includes a lifting structure  130  described in detail below. 
         [0023]    The cart  100  may include four casters: two front casters  120  and two rear casters  110  (only one shown in  FIG. 1 ). Both the rear and front and casters  110 , 120  are configured to rotate around a horizontal axis such as axle  112 ,  122  (only two shown). The front casters may be configured to rotate, swivel or pivot about a vertical axis  272  (shown in  FIG. 2 ). On the other hand, as mentioned above, the rear casters  110  may be configured not to rotate about a vertical axis, which may cause difficulty in transporting and steering a line of the carts nested together. 
         [0024]    As shown in  FIG. 2 , the tray  106  may be formed of multiple longitudinal bars  202 ,  204 ,  206 ,  208 ,  210 ,  212 ,  214  extending between the front and rear ends of the tray, and cross bars  222 ,  226 ,  242 ,  224  traversing some or all of the longitudinal rods. The longitudinal bars  202 ,  204 ,  206 ,  208 ,  210 ,  212 ,  214  and cross bars  222 ,  226 ,  242 ,  224  may be formed of metal and may be bent to the desired shape and then spot welded together to form the tray  106 . Subsequent to this construction of tray  106 , the tray  106  may be chrome-plated, powder coated, or the like to prevent or reduce corrosion. It should be noted, however, that although a particular construction of the tray  106  is described herein, any type of tray material and/or configuration may be employed. In particular, it is contemplated that tray  106  may employ a molded plastic construction or any other known type of construction as long as the lifting structure  130  can be formed thereon or therein. Also, the tray  160  may be constructed to provide a light weight yet strong support structure that will allow a shopper to utilize the space above the casters  110 ,  120  and below the basket  102  and also function to be or to hold the lifting structure  130 . 
         [0025]    The frame  104  is constructed to provide sufficient support for the basket  102 , the tray  106  and the handle  124 . The frame  104  may include vertical uprights  243 ,  244 ,  245 ,  246 , horizontal members  232 ,  234 ,  236 , and may include other structure known to those in the art. The frame  104  is mounted on and supported by the front and rear casters  110 ,  120 . The front casters  120  may be attached to the bottom surface of a front caster panel  230 , which is attached to the horizontal members  232 ,  234  of the frame  104 . The rear casters  110  may be attached to the bottom ends the vertical uprights  243 ,  245  of the frame  104 . For example, an axle support  268  supporting the horizontal axle  112  of the rear caster  110  may be connected to frame  104  via a connector  270 . No vertical axle may be provided to the rear casters  110  such that the rear casters  110  do not to swivel. Contrarily, the front casters  120  may be configured to swivel by pivotally connecting the axle support  266  supporting a horizontal axle  122  to the front caster panel  230  via a vertical axle  272 . 
         [0026]      FIGS. 2 and 3  show an exemplary construction of the lifting structure  130  arranged on the tray  106 . The lifting structure  130  may include a ramp area  302  at the front most of the tray  106 . This ramp area  302  provides a smooth transition surface for engaging the cross rod  224  or any similar structure of a preceding cart. The lifting structure  130  may further include a flat area  304  that holds or retains the cross rod  224  of the preceding cart (not shown in  FIGS. 2 and 3 ). The ramp area  302  and the flat area  304  are separated by a lip area  303  that is vertically higher than ramp area  302  and flat area  304  and thus resists the preceding cart from sliding off the flat area  304 . 
         [0027]    In operation, the shopping cart  100  is nested to the preceding cart. As the cross rod  224  of the preceding cart traverses the ramp area  302 , the rear portion of the preceding cart is lifted, which results in lifting of the rear casters  110 ,  110  of the preceding cart from the ground. After traversing the ramp area  302 , the cross rod  224  of the preceding cart may cross over the lip area  303  and be positioned on the flat area  304 , which maintains the rear casters of the preceding cart off the ground. The preceding cart may be more or less locked or restrained on the flat  304  by the lip area  303 . 
         [0028]    The lifting structure  130  may be constructed integral to the tray  106 , or the lifting structure  130  and the tray  106  may be manufactured separately, assembled together via engagement mechanism, or the like.  FIG. 3  shows an exemplary lifting structure  130  attached to the longitudinal rods  206 ,  208 ,  210  and the cross bar  242 . More specifically, the lifting structure  130  may include slots  306 ,  308 ,  310 . These slots may engage to the longitudinal rods  206 ,  208 ,  210  respectively and provide the lifting structure  130  a tight engagement to the tray  106 . Further, the lifting structure  130  may include rear slots  312 ,  314 ,  316  which may allow the lifting structure  130  to be inserted into the tray  106  between the rods  206 ,  208 ,  210  while in a vertical orientation and rotated such that slots  306 ,  308 ,  310  engaged to the rods  206 ,  208 ,  210 . Further, a rear slot  318  may engage the cross rod  242 . The engagement of the slots  306 ,  308 ,  310 ,  312 ,  314 ,  316  and the rear slot  318  with the longitudinal rods  206 ,  208 ,  210  and the cross rod  242  provides a secure attachment to the tray  106 . It should be noted that the foregoing is merely an exemplary attachment configuration and that any known attachment is contemplated by the invention. 
         [0029]    In  FIG. 4 , which shows a side view of the shopping cart  100 , the lifting structure  130  is positioned about mid way along the tray  106 . It should be apparent, however, that the lifting structure  130  may be positioned at any point along tray  106 , as is contemplated in the invention. The lifting structure  130  provides a vertically higher upper surface than tray  106 . Moreover, the lip  303  may be even higher than the lift surface  304  of the lifting structure  130 . The tray  106  may be constructed to have a more flexible construction as compared with the frame  104 . In this regard, positioning the lifting structure  130  on the tray  106  forms a flexible support for the lifting structure  130 . Accordingly, when the weight on the lifting structure  130  becomes too great, the tray  106  may flex and the casters of the preceding carts that have been lifted by the lifting structure  130  may be lowered. This will reduce stress applied to the frame  104 . 
         [0030]      FIGS. 5 and 6  show the nesting operation of the shopping cart  100 , together with a preceding shopping cart  100 P, in which the tray  106  of the shopping cart  100  is concatenated with the tray  106 P of the preceding cart  100 P. The tray  106 P, and more specifically the cross rod  224 P of the preceding cart  100 P may engage with the lifting structure  130  of the shopping cart  100 . This engagement causes the rear casters  110 P of the preceding cart  100 P to be lifted off the ground or other rolling surface and be held elevated above the same.  FIG. 6  shows in further perspective detail the operation of lifting structure  130  operating as described in  FIG. 5  above. 
         [0031]      FIG. 7  shows a further operation of the lifting structure  130  of the invention in which a series of the shopping carts are nested together. In particular, the shopping cart  100  is inserted to a preceding cart  100 P and a subsequent cart  100 S is inserted to the shopping cart  100  and the preceding cart  100 P. As shown in  FIG. 7 , the rear casters  110 P of the preceding cart  100 P and the rear casters  110  of the shopping cart  100  are lifted from the horizontal surface or ground G. This results in fewer casters on the ground, such as only the front casters  120 P,  120  and  120 S of the shopping carts  100 P,  100 ,  100 S and the rear casters  110 S of shopping cart  100 S. Thus, according to the invention, steering and transportation of a line of shopping carts nested together become much easier, especially when the rear casters are configured not to swivel. Although only three shopping carts are nested in  FIG. 7 , it should be understood that any number of shopping carts may be nested or concatenated together in order to move the group of shopping carts from one location, such as a parking lot to inside the store. In this case, only three shopping carts are shown for simplicity of description. 
         [0032]      FIG. 8  shows an exemplary construction of the lifting structure  130  as seen from underneath the shopping cart  100 . In particular, the lifting structure  130  is shown with longitudinal slots  316 ,  314  and  312  engaged to the longitudinal rods  206 ,  208  and  210  respectively, and a rear slot  318  engaged to the cross rod  242 . The lifting structure  130  may further include engagement portions  506 ,  508 ,  510  that may snap fit to each of the longitudinal rods  206 ,  208  and  210  to provide a firm connection for the lifting structure  130  to the tray  106  and, in particular, the longitudinal rods  206 ,  208  and  210 . 
         [0033]    In the invention, the lifting structure  130  is contemplated as being molded from a material such as plastic, fiberglass, and the like. However, it is contemplated that the lifting structure  130  may also be integral with a plastic tray or formed with rods of a metallic tray as shown in  FIG. 9 . In such an implementation, the features of the lifting structure  130  would merely be molded in the tray or formed in the rod construction of the tray  106 , providing the same lifting function as the separate lifting structure  130  and tray  106  described above. In this regard,  FIG. 9  shows a ramp area  302 , lip  303 , and flat area  304  arranged as integral part of the tray  106 . Moreover, the features of the caster lift  130  may be arranged in the shopping cart  100  without a tray  106 . In such an implementation, a support structure may be employed to position the lift structure  130  in an operative position. The support structure may employ rods or any other known support structure. 
         [0034]    While the invention has been described in terms of exemplary embodiments, those skilled in the art will recognize that the invention can be practiced with modifications in the spirit and scope of the appended claims. These examples given above are merely illustrative and are not meant to be an exhaustive list of all possible designs, embodiments, applications or modifications of the invention.