Patent Publication Number: US-2004046341-A1

Title: Shopping cart having caster lift

Description:
TECHNICAL FIELD OF THE INVENTION  
       [0001] This invention pertains to a shopping cart, which is nestable into a preceding, similarly constructed cart and into which a following, similarly constructed cart is nestable. This invention provides the shopping cart with a rear caster-lifting capability, which reduces wear and damage to rear casters of the shopping cart.  
       BACKGROUND OF THE INVENTION  
       [0002] Conventionally, a shopping cart is designed to be nestable into a preceding, similarly constructed cart and to enable a following, similarly constructed cart to be nested into the shopping cart. Commonly, in retail stores and in parking areas near retail stores, long lines of nested shopping carts may be formed, which must be moved by store personnel.  
       [0003] Typically, a rear caster comprises a horn, which unlike the horn of a front caster does not swivel and which mounts an axle, and a wheel, which is journalled on the axle, via a bearing, and which has a tread. Moving of a line of nested shopping carts stresses rear casters of the nested carts, tends to cause the horns of said casters to bend, and tends to cause the bearings and treads of said casters to wear excessively, particularly as attempts are made to turn the line of nested shopping carts.  
       SUMMARY OF THE INVENTION  
       [0004] This invention provides a shopping cart, which is nestable into a preceding, similarly constructed cart and into which a following, similarly constructed cart is nestable, wherein the shopping cart comprises a chassis, which has front and rear casters including two rear, transversely spaced casters, which has a transversely extending structure, and which has a camming structure. The camming structure of the shopping cart is adapted to cam the transversely extending structure of a preceding, similarly constructed cart, into which the shopping cart is being nested, upwardly so as to elevate the rear casters of the preceding, similarly constructed cart. The transversely extending structure of the shopping cart is adapted to be cammed upwardly by the camming structure of a following, similarly constructed cart, which is being nested into the shopping cart, so as to elevate the rear casters of the shopping cart.  
       [0005] Preferably, the camming structure of the shopping cart defines an upper, generally horizontal platform, on which the transversely extending structure of a preceding, similarly constructed cart can be seated after having been cammed upwardly. Preferably, the camming structure comprises similarly shaped, transversely spaced, camming elements. Preferably, each camming element of the shopping cart defines an upper, generally horizontal platform, on which the transversely extending structure of a preceding, similarly constructed cart can be seated after having been cammed upwardly. Preferably, the transversely extending structure of the shopping cart comprises a bar, which extends across the chassis of the shopping cart. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0006]FIG. 1 is a longitudinal cross-section of a shopping cart standing on a horizontal surface and constituting a preferred embodiment of this invention.  
     [0007]FIG. 2 is a fragmentary, side elevation of lower structures of the shopping cart and of lower structures of a similar cart being nested into the shopping cart.  
     [0008]FIG. 3 is a fragmentary, side elevation of lower structures of the shopping cart and of lower structures of the similar cart after having been nested into the shopping cart.  
     [0009]FIG. 4, on an enlarged scale compared to FIGS. 1, 2, and  3 , is a fragmentary, perspective detail of what is illustrated in FIG. 3, from a front, side vantage.  
     [0010]FIGS. 5, 6, and  7 , on an enlarged scale compared to FIG. 4, are views of an exemplary one of two camming elements of the shopping cart, FIG. 5 being an upper plan, FIG. 6 being a side elevation, and FIG. 7 being a front elevation. 
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT  
     [0011] As illustrated in FIG. 1, a shopping cart  10  constituting a preferred embodiment of this invention is similar, except as disclosed herein, to the shopping cart disclosed in U.S. Pat. No. 5,791,666, the disclosure of which is incorporated herein by reference. The shopping cart  10  is illustrated as standing on an underlying surface S, such as a floor.  
     [0012] The shopping cart  10  comprises a chassis  20  having two longitudinally extending, tubular steel members  22 , one along each side of the chassis  20 , having two rear, tubular steel uprights  24 , which are welded to the longitudinally extending members  22  and which extend frontwardly at the upper ends  26  of the rear uprights  24 , and having two intermediate, tubular steel uprights  28 , which are welded to the longitudinally extending members  22 , at the lower ends  30  of the intermediate uprights  28 , and to the rear uprights  24 , at the upper ends  28  of the rear uprights  24 . The shopping cart  10  comprises a handle assembly  32 , which includes two generally vertically extending, transversely spaced, tubular steel uprights  34 , a transverse handle  36 , which extends between the handle uprights  34 . The shopping cart  10  comprises a basket  38 , which is mounted to the chassis  20  and to the handle assembly  32 .  
     [0013] The chassis  20  has two front, transversely spaced casters  40 , which are mounted to the chassis  20 , and two rear, transversely spaced casters  50 , which are mounted to the chassis  20 . Each front caster  40  comprises a horn  42 , which is adapted to swivel about a vertical axis, an axle  44 , which is mounted operatively to the horn  42 , and a wheel  46 , which is journalled on the axle  44 , via a bearing, and which has a tread  48 . Each rear caster  50  comprises a horn  52 , which is not adapted to swivel, an axle  54 , which is mounted operatively to the horn  52 , and a wheel  56 , which is journalled on the axle  54 , via a bearing, and which has a tread  58 . The bearings of the casters  40 ,  50 , are concealed in the drawings.  
     [0014] The chassis  20  has a transversely extending bar  100 , which is welded at its opposite ends  102  to the rear uprights  24  so as to extend across the chassis  20 . The chassis  20  has two similarly shaped, transversely spaced, camming elements  110 , which are molded from a suitable engineering polymer, such as nylon  6 , and which are mounted to the chassis  20  so as to be frontward of the transversely extending bar  100 , about midway between the front casters  30  and the rear casters  40 . Each camming element  110  has a rear, bifurcated end  112 , which embraces one of the intermediate uprights  28  and which is drawn together by a fastener (not illustrated) passing through aligned holes  114  in said end  112 . Each camming element  110  has a lower, bifurcated end  116 , which is snapped over the lower ends  30  of the intermediate uprights  28  and over the longitudinally extending members  22  so as to cover welds between the lower ends  30  of the intermediate uprights  28  and the longitudinally extending members  22 . Each camming element  110  has a convex, front edge  120  and a flat, upper edge  130 .  
     [0015] In connection with FIGS. 2 and 3, in which the chassis, casters, and other lower portions of two shopping carts are illustrated, each being constructed as the shopping cart  10  is constructed and each standing on the underlying surface S, it is convenient to refer to the right-hand cart as a preceding cart  10 A and to refer to the left-hand cart as a following cart  10 B. The preceding cart  10 A has a transversely extending bar  100 A, which is similar to the transversely extending bar  100  of the shopping cart  10 , and the following cart  10 B has two camming elements  110 B, which are similar to the camming elements  110  of the shopping cart  10 . The camming elements  110 B are mounted on the intermediate uprights  28 B, which are similar to the intermediate uprights  28  of the shopping cart  10 . Each camming element  110 B has a convex, front edge  120 B and a flat, upper edge  130 B. The preceding cart  10 A has two rear casters  50 A, which are similar to the rear casters  50  of the shopping cart  10 .  
     [0016] As illustrated in FIGS. 2 and 3, the convex, front edges  120 B of the camming elements  110 B of the following cart  10 B are adapted to cam the transversely extending bar  100 A of the preceding cart  10 A, into which the following cart  10 B is being nested, upwardly so as to elevate the rear casters  40 A of the preceding cart  10 A above the underlying surface S. Moreover, the transversely extending bar  100 A of the preceding cart  10  is adapted to be cammed upwardly by convex, front edges  120 B of the camming elements  110 B of the following cart  10 B, which is being nested into the preceding cart  10 A, so as to elevate the rear casters  40 A of the preceding cart  10 A. Furthermore, the flat, upper edges  130   130 B of the camming elements  110  of the following cart  10 B define an upper, generally horizontal platform, on which the transversely extending bar  100 A of the preceding cart  10 A can be seated after having been cammed upwardly. Nesting of the following cart  10 B into the preceding cart  10 A is limited by engagement of the transversely extending bar  10 A of the preceding cart  10 A with the intermediate uprights  28  of the following cart  10 B.  
     [0017] The shopping carts  10 A,  10 B, exemplify any two nested carts in a long line of nested shopping carts. Because the rear casters of the nested carts are elevated above the underlying surface, except for the rear casters of the final cart in the line, moving of the line of nested shopping carts does not stress the elevated casters, does not tend to cause the horns of the elevated casters to bend, and does not tend to cause the bearings or treads of the elevated casters to wear excessively, particularly as attempts are made to turn the line of nested shopping carts. Because all casters touching the underlying surface can swivel, except for the rear casters of the final cart in the line, the line can be turned easily.