Abstract:
A shopping cart comprised of separate basket and frame portions is assembled at the point of use without welding or special tools by a mechanical engagement of basket portion rim wires into clips. The method of assembling the cart includes orienting the basket with its rim wires relative to the frame and its clips such that the rim wires can be placed into a rear clip, rotated to lock the rim wires into the rear clip and rotated further to latch the rim wires to a front clip.

Description:
BACKGROUND 
       [0001]    Shopping carts, which are comprised of a wheeled frame to which a wire-mesh basket is affixed, are relatively light but nevertheless bulky. While they are designed to be telescoped together, i.e., placing the front end of the basket into a movable rear panel, wire-mesh shopping carts are relatively difficult to economically package and ship in their assembled state. A method and apparatus for facilitating the shipment of frame and basket portions in a disassembled state and which allows the separate portions to be assembled at their point of use, would be an improvement over the prior art. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0002]      FIG. 1  is a perspective view of a shopping cart assembly; 
           [0003]      FIG. 2  is an isolated perspective view of the shopping cart assembly; 
           [0004]      FIG. 3  is an isolated view of the spring wire attached to a rim wire by two welds; 
           [0005]      FIG. 4  is a top view of the spring wire lying in a horizontal plane and showing how the spring wire, with an included loop or detent, is oriented when it is attached to a rim wire; 
           [0006]      FIG. 5A  and  FIGS. 5B and 5C  are top views of a spring wire having a rim wire attached below the spring wire and showing the action of the two wires relative to each other as they are driven onto a wire spade connector; 
           [0007]      FIG. 6  is a depiction of the frame portion showing the spade connector formed on the opposing ends of a relatively stiff heavy gauge generally U-shaped wire connecting rod; 
           [0008]      FIG. 7  shows a basket portion attached to a frame portion using the aforementioned two-wire trap; 
           [0009]      FIG. 8  is a perspective view of the spade connector; and 
           [0010]      FIG. 9  is a typical stress-strain curve. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]      FIG. 1  is a perspective view of a shopping cart assembly  100 . The shopping cart assembly  100  is comprised of a wire basket portion  200  and a frame portion  300 . The basket portion  200 , which is also referred to herein simply as “the basket” has a wire-mesh bottom  202  and two opposing wire-mesh sides or sidewalls  204  and  206 . A wire-mesh front end  208  and a wire-mesh inclined back end  210  define a wire-mesh basket with an open top  212 . The wire-mesh inclined back end  210  is able to flip up, i.e., rotate inwardly, around a hinge-like connection  215  located in front of the horizontal handle portion  214 . Relatively heavy-gauge wires denominated herein as “rim” wires  228  are stiff and provide strength to the sidewalls  204  and  206  and the bottom  202 . 
         [0012]    The basket portion handle  214  is comprised of an elongated length of relatively large-diameter tubing or tube  216  bent or otherwise formed to provide a horizontal user portion  214  having a width  218  that is slightly larger than the overall width  220  of the inclined back end  210 . Two sloping or inclined handle extensions  222  extend downwardly from two, horizontal and forwardly-extending handle portions  224  to where the angled handle extensions  222  meet and are attached to a rim wire-reinforcing spring wire  226 . The inclined portions  222  are shown as being inclined at an angle θ (theta) relative to the bottom  202 . The inclined handle portions  222  have bottom ends  223  that are attached to substantially horizontal spring wires  226 . 
         [0013]      FIG. 2  is a perspective view of the shopping cart assembly  100  but showing an isolated portion of the inclined handle member  222 . As stated above, the inclined handle member  222  is formed from an elongated tube  216  that also forms the handle  214  shown in  FIG. 1 . The bottom end  223  of the inclined handle portion or member  222  of the elongated tube  216  is fixedly attached to a horizontally-oriented spring wire  226  preferably by welding. The horizontal-oriented spring wire  226  is so named because the spring wire  226  extends away from the bottom end  223  of the inclined handle member  222  substantially horizontal to a surface on which the basket assembly is used and because the spring wire  226  acts as a spring, when it is attached to a basket rim wire  228 , which is also considered to be horizontal or at least substantially horizontal. 
         [0014]    In a preferred embodiment, the horizontal spring wire  226  is solid with a circular or substantially-circular cross section, an overall length of between about six and twenty inches. Two opposing ends of the horizontal spring wire  226  are identified by reference numerals  240  and  242 . (See  FIG. 2  and  FIG. 4 .) In an alternate embodiment, the spring wire  226  can be hollow. In other embodiments, it can have cross-sectional shapes that are square, rectangular, triangular, oval or elliptical. For purposes of claim construction, the term, spring wire should be construed to include such other embodiments. 
         [0015]    The spring wire  226  is attached to the rim wire  228  at or near locations that are near or proximate to the two ends  240 ,  242 . The spring wire&#39;s attachment points are identified in  FIG. 2  by reference numerals  230  and  232 . They are preferably welds or “weldments” and are referred to herein after as the horizontal spring wire attachment points  230  and  232 . In one embodiment (not shown), the attachment points  230  and  232  are co-located at the two ends  240  and  242  of the spring wire  226 . The material from which the spring wire  226  is made, its cross sectional shape and the space or separation distance between the attachment points  230  and  232  determines the stiffness provided by the spring wire  226  relative to the rim wire  228  to which it is attached. 
         [0016]    As described more fully below and in the applicant&#39;s co-pending patent application entitled “Basket-to-Frame Locking Clip,” which was filed 29 Mar. 2012, and having Ser. No. 13/433,928, and which is incorporated herein by reference in its entirety, the basket portion  200  and the frame portion  300  are “snapped” together using clips. The rear clips  308  enable the basket portion  200  to be attached to the frame portion  300  without tools. Increasing the stiffness of a rim wire that is “clipped” to a front-located basket-to-frame locking clip through a connector will increase the strength and ruggedness of the basket after the basket portion and frame portions are snapped together. 
         [0017]    When the horizontal spring wire  226  is attached to a rim wire  228 , it and the portion of the rim wire  228  that it is connected to, act together as a spring-like clip or two-wire “trap” for a basket-to-frame locking clip, such as the wire spade  302  shown in the figures or the clip disclosed in the aforementioned co-pending &#39;928 application. The horizontal spring wire  226  also imbues an associated rim wire  228 , i.e., a rim wire  228  to which the spring wire  226  is attached, a significantly increased stiffness along the length of the rim wire  228  to which the spring wire  226  is attached. The spring wire  226  in combination with the rim wire  228  thus provides both a spring-like clip and localized increased stiffness to the rim wire  228 , i.e., an increased stiffness localized to where the spring wire  226  is attached, increasing or improving an assembled basket  100  ruggedness. The spring wire  226  obviates the need to manufacture the basket portion  200  with a horizontal rim wire  228  that would otherwise need to be much larger in diameter. The spring wire  226  thus enables the basket portion  200  to be lighter and less costly to manufacture. 
         [0018]      FIG. 3  is a more isolated view of the spring wire  226  showing its attachment to the rim wire  228  by a first weldment or weld joint  230  located near the first end  240  of the spring wire  226  and just in front of the back or rear end  210  of the basket portion  200 . A second attachment or weldment is located near the opposite, second end  242  of the spring wire  226 . The spaced-apart attachment points of the spring wire  226  to the rim wire  228  thus leaves an “intermediate” portion of the spring wire  226 , i.e., the spring wire portion between the joints  230  and  232 , unconnected or “free” to move laterally or “sideways” relative to the rim wire  228  that is also between the two weldments  230  and  232 . The portion of the spring wire  226  and the portion of the rim wire  228  between the two joints  230 ,  232  are both able to deflect, relative to each other. The assembly also comprises a wire basket attachment spade  302  having a chamfered top end  310  and a slot  312  (See  FIGS. 4 ,  7  and  8 .) into which the rim wire  228  can be held. The two wires  226 ,  228  thus form a trap for the spade  302 . 
         [0019]      FIG. 4  is a top view of the spring wire  226  shown lying in a horizontal plane and showing how the spring wire  226  is oriented when it is attached to a rim wire  228 . The spring wire  226  has a first end  240  and an opposing second end  242 . The space between them defines the length  244  of the spring wire, which is preferably about 12-14 inches but can be as short as 6-8 inches or as long as the side  204 ,  206  of the wire basket portion  200 . 
         [0020]    A U-shaped “detent” portion  234  is formed approximately midway between the two ends  240  and  242 . In a preferred embodiment, the U-shaped detent  234  has a width  246  and a depth  248  selected such that when the spring wire  226  is attached to a rim wire, the assembly of the spring wire  226  to a straight rim wire  228  forms a hole  236  (as shown in  FIG. 4 ) into which the spade  302  can be forcibly fit, causing the two wires to deflect outwardly from each other. Stated another way, in a preferred embodiment, the spade  302  has an outside diameter too big to freely slide into and through the “hole”  236  formed by the U-shaped detent  234  and a rim wire to which the spring wire  226  would be attached. Forcibly driving the combination spring wire  226  and rim wire  228  downwardly over the upright-oriented spade  302 , as will happen when the basket portion  200  is attached to two, rear-located clips  308  (as shown in  FIG. 2 ) and rotated toward the spade  302 , will cause the two wires  226  and  228  to deflect outwardly from each other. Their elasticity will cause them to “trap” or engage the spade  302  and force the rim wire  228  of the basket portion  200  into the slot  312  as shown in  FIG. 3 . 
         [0021]      FIG. 5A  and  FIGS. 5B and 5C  are top views of a spring wire  226  having a rim wire  228  attached below the spring wire  226 . The U-shaped detent  234  projects outwardly and away from the rim wire  228  to define a hole  236 . A portion of the top of the spade  302  can be seen in  FIG. 5A  as being located beneath the two wires  226 ,  228 . Stated another way, in  FIG. 5A , the two joined-together wires  226  and  228  are at rest atop the spade  302 . 
         [0022]      FIG. 5B  shows the two wires being deflected away from each other as the two wires  226 ,  228  are driven over the chamfered top  310  of the spade  302 , which happens when the basket portion  200  of the basket assembly  100  is being attached to the frame portion  300  using the process described in the aforementioned co-pending patent applications. The chamfered top  310  and the spade  302  thus act to provide a wire-separating force that is applied to both wires, which separates the wires  226  and  228  from each other as the chamfer  310  and wires  226 ,  228  are driven past each other. Wedge-shaped openings can be seen between the two wires  226  and  228  due to the outward deflection of the two wires  226 ,  228 . 
         [0023]      FIG. 5C  shows the two wires  226 ,  228  after the rim wire  228  snaps into and is captured by a notch  312  formed into the spade  302 . The two wires  226 ,  228  are considered to have trapped the rim wire  228  into the notch  312  in the spade  302 , or vice versa. 
         [0024]    The spring wire  226  is preferably attached to the rim wire  228  by welding because welding is relatively fast, durable and inexpensive. The spring wire  226  can be made of a spring steel, however, spring steel tends to anneal when subjected to high temperatures, especially those common to welding. A low carbon steel is therefore preferred because of its lower cost as compared to spring steels and because it is generally easier to weld than spring steels. The physical characteristics of the spring wire  226  are chosen so that the spring wire  226  deflection relative to the rim wire  228  during assembly of the basket portion  200  to the frame portion  300  is well within the linear portion of both of the wires&#39; stress-strain curves. See  FIG. 9 . 
         [0025]      FIG. 6  is a depiction of the frame portion  300  but also showing the spade connectors  302  formed on the opposing ends of a relatively stiff heavy gauge generally U-shaped wire connecting rod  304 . The spade portion  302  is provided with a basket-to-frame locking clip  306  as described in the applicant&#39;s co-pending application Ser. No. 13/433,928 entitled “Basket-to-Frame Locking Clip” filed Mar. 29, 2012, the entire content of which is incorporated herein by reference. A rear basket-to-frame locking clip  308  described in the applicant&#39;s co-pending patent application Ser. No. t.ba., incorporated herein by reference, is also shown. 
         [0026]    Referring now to  FIG. 7 , a basket portion  200  is attached to a frame portion  300  using the aforementioned wire clips  306  and  308 . When the basket portion is to be attached to the frame portion, two rear-located rim wires  602  and  604  are placed into the rear basket-to-frame locking clip  308  as described in the aforementioned patent application Ser. No. ( ). The rim wires  602  and  604  can be rotated as described in the (tba) application until the downwardly and inclined handle portion  222  attached to the spring wire  226  meets the upright-standing spade portion  302 . A downward force on the basket portion drives the rim wire  228  over an inclined chamfer  310  on the upright spade portion  302  until the rim wire  228  and spring wire  226  separate from each other to allow the spade  302  to slide between them. The rim wire  228  and spring wire  226  are forced downwardly over and past the chamfer  310  of the spade  302  until the rim wire  228  latches into the notch  312  effectively locking the rim wire  228  into the spade  302  by virtue of the additional stiffness provided by the spring wire  226  and the clamping force provided to the spade  302  by the wires&#39; rigidities. As shown in  FIG. 4 , the detent  234  receives the spade portion  302  at the same time the spring wire  226  maintains the rim wire  228  in a relatively straight and latched condition inside the spade  302 . 
         [0027]      FIG. 8  shows details of the wire basket attachment spade  302 . The long, straight portion is the wire connecting rod  304 . The slots  312  on the sides of both spades  302  are located below the chamfers  310 . The chamfers  310  allow or facilitate the spade&#39;s insertion into the holes  236  between the spring wires  226  and the rim wires  228 . The slots  312  formed in the spades  302 , which are attached to the frame portion  300 , lock the basket portion  200  to the frame portion  300 . 
         [0028]    The foregoing description is purposes of illustration only. The true scope of the invention is set forth in the appurtenant claims.