Abstract:
The present invention provides a collapsible transportation device comprising a receptacle with a vertically movable bottom wall. The receptacle expands and collapses vertically to facilitate in loading and unloading different amounts of items in the cart, and in storing the cart when not in use. The vertical movement of the bottom wall may be controlled by a biasing assembly including multiple pairs of springs.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit under 35 U.S.C. 119(e) of U.S. Provisional Patent Application No. 60/941,649 filed on Jun. 1, 2007, the entire contents of which are herein incorporated fully by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to land vehicles adapted to carry a load from one place to another, especially such land vehicles provided with supporting wheels to engage the surface over which the vehicle moves (e.g., shopping carts). This invention also relates to such land vehicles with perfecting features to facilitate the unloading of a basket (e.g., to assist in transferring items to be purchased from a shopping cart to a checkout counter). This invention also relates to such land vehicles that allow their dimensions to vary (e.g., by folding from a condition of use to a more compact or smaller non-use form for ease of storage or transport). 
         [0004]    2. Description of the Prior Art 
         [0005]    Shopping carts accommodate the transportation of purchased items, for example, to a vehicle or a residence. Typically, shopping carts have a basket or other receptacle for holding items to be purchased, the basket is mounted within a rigid, non-collapsible frame that has a handle and four caster-type wheels, and the either the entire basket or the rear wall thereof is adapted to pivot or articulate so that a part of a second shopping cart will at least partially interfit or be received within the boundaries of the basket to produce a nesting relation. 
         [0006]    However, a shopping cart with a basket of fixed size can be very inconvenient. It must be large enough to hold many items, and reaching items may require the user to reach or bend down or over. Such bending movement may be painful or even difficult for certain users of a typical shopping cart. Thus, there is a need for shopping carts adapted to facilitate the retrieving of the contents therein without having a user to reach or bend down into the shopping cart basket. 
         [0007]    The size, shape, and weight of a traditional, rigid, non-collapsible cart and its fixed basket can also be a disadvantage. When a shopping cart is used to transport items for any distance outside of a store&#39;s immediate vicinity (e.g., a few city blocks), lighter weight, smaller size, and more compact shape are obvious advantages. Moreover, traditional shopping carts are unsuitable for transport in a larger vehicle, such as a taxi or public bus. A traditional shopping cart requires a large storage space when not in use and, thusly, cannot be conveniently stored in, for example, an apartment. Thus, there is a need for a collapsible shopping cart with the above mentioned ability to facilitate the retrieving of contents therein. 
       SUMMARY OF THE INVENTION 
       [0008]    In light of the needs described above, the present invention provides a collapsible transportation device comprising a receptacle with a vertically movable bottom wall. The receptacle expands and collapses vertically to facilitate in loading and unloading different amounts of items in the cart, and in storing the cart when not in use. The vertical movement of the bottom wall may be controlled by a biasing assembly including multiple pairs of springs. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0009]    The above and other features of the inventive cart will become more readily apparent from the following detailed description of the invention in conjunction with accompanying drawings, in which: 
           [0010]      FIGS. 1A-1C  are perspective views of a shopping cart according to a preferred embodiment shown with an unloaded receptacle in an expanded position and connected to the outer frame; 
           [0011]      FIG. 2  is a perspective view of the shopping cart of  FIGS. 1A-1C  with the rear pouch lifted; 
           [0012]      FIG. 3A  is a side view of the shopping cart of  FIGS. 1A-1C  with the receptacle collapsed; 
           [0013]      FIG. 3B  is a rear view of the shopping cart of  FIGS. 1A-1C  with the receptacle collapsed; 
           [0014]      FIG. 3C  is a front view of the shopping cart of  FIGS. 1A-1C  with the receptacle collapsed; 
           [0015]      FIG. 4  is a perspective view of the shopping cart of  FIGS. 1A-1C  when collapsed; 
           [0016]      FIG. 5  is a perspective view showing the magnetic catch of the collapsed shopping cart in  FIG. 4 ; 
           [0017]      FIG. 6  is a perspective view showing a brake assembly and child seat of a shopping cart according to the present invention; 
           [0018]      FIG. 7  is a top view of the brake assembly of  FIG. 6 ; and 
           [0019]      FIG. 8  is a partially cross-sectioned side elevational view of the brake assembly of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    Reference will now be made in detail to an embodiment of the invention that is illustrated in the accompanying figures. Wherever possible, same or similar reference numerals are used in the figures and the description to refer to the same or like parts. For purposes of convenience and clarity only, directional terms, such as top, bottom, left, right, up, down, over, above, below, beneath, upper, lower, rear, and front may be used with respect to the figures. For example, as used herein, the term “moves vertically” includes movement in a direction normal to the ground and any other non-normal direction having a substantially vertical component. These and similar directional terms should not be construed to limit the scope of the invention in any manner. 
         [0021]    A shopping cart according to the present invention comprises a wheel assembly and a load-bearing assembly, which load bearing assembly comprises an outer frame and an inner frame. The wheel assembly supports the load-bearing assembly and is adapted to engage the surface over which the shopping cart moves (e.g., with wheels). The outer frame of the load-bearing assembly is attached to the wheel assembly, and, significantly, is adapted to allow its dimensions to vary (e.g., by collapsing or folding from a condition of use to a more compact or smaller non-use form for ease of storage or transport). The inner frame of the load-bearing assembly is attached to the outer frame and, importantly, is adapted to facilitate its loading and unloading (e.g., by expanding and/or contracting). 
         [0022]    Referring to the figures, there is shown a shopping cart according to the present invention comprising a wheel assembly that comprises a plurality of wheels and axles arranged to support and maneuver the load-bearing assembly and any load therein. The wheel assembly for the preferred embodiment shown in the drawings comprises lower rear horizontal member  13  and lower front horizontal member  15 . As shown, lower rear horizontal member  13  and lower front horizontal member  15  are essentially fixed axles. Lower rear horizontal member  13  comprises two non-caster wheels  30  and lower front horizontal member  15  comprises a caster wheel  40 . Although the preferred embodiment shown in the drawings comprises three wheels, two of which are non-caster wheels, the wheel assembly may, of course, comprise three, four, or more wheels, any number of which may be caster or non-caster wheels. Moreover, the wheel assembly may include a shelf extending horizontally between lower horizontal members  13 ,  15 . 
         [0023]    A shopping cart according to the present invention comprises a collapsible outer frame comprising vertical side members attached to the wheel assembly and adapted to collapse or fold, upper horizontal members for supporting an inner frame, and a handle. As shown, the collapsible outer frame for the preferred embodiment comprises: a pair of vertical side members  11 ,  12  attached to lower horizontal members  13 ,  15 , respectively; a pair of upper horizontal members  14 ,  17 ; and a handle  16 . Side member  11  is attached to upper front horizontal member  14 , while side member  12  is attached to upper rear horizontal member  17 . Handle  16  is attached to side member  12 . A safety strap  110 , as shown in  FIG. 3A , is connected between upper horizontal support members  14 ,  17 . A closure  120  comprising two parts, one on each of crossing members  11 ,  12 , as discussed in more detail herein below, is adapted to keep the outer frame positioned in a collapsed position. 
         [0024]    To allow collapsing or folding, side members  11 ,  12  may be arranged in any suitable manner (e.g., revolute joint (“pivot”), prismatic joint (“slider”), cylindrical joint, screw joint, planar joint, spherical joint (“ball and socket”)). As shown, side members  11 ,  12  cross each other at about their respective mid-points and that crossing point is also the location of a common pivot joint  20 . The preferred pivot joint will, of course, comprise a suitable arrangement of parts (e.g., bolts, pins, screws, rivets, bushings, bearings, holes, etc.) and, for example, may be a bolt  18  that passes through juxtaposed holes in side members  11 ,  12 . 
         [0025]    To support an inner frame, upper horizontal members  14 ,  17  are preferably integrated with side members  11 ,  12 , respectively. The dimensions of upper horizontal members  14 ,  17  will generally determine the maximum horizontal size the inner frame. As shown in the figures, upper front horizontal member  14  is slightly shorter than upper rear horizontal member  17  because side member  11  crosses inboard of side member  12 . Therefore, rear horizontal member  17  may be provided with spacers  310  (as best seen in  FIG. 3B ) that will position the inner frame both centrally upon rear upper horizontal member  17  and squarely to front upper horizontal member  14 . 
         [0026]    A shopping cart according to the present invention comprises an expandable inner frame comprising an upper support member attached to the collapsible outer frame (e.g., by hooks or other suitable mechanism), flexible side walls, a bottom wall, one or more lower support members adapted to hold the flexible side walls apart and disposed below the upper support member, and expandable members adapted to lower and/or raise the bottom wall and connecting the upper support member to at least one of lower support members and/or the bottom wall. As shown, the expandable inner frame for the preferred embodiment comprises: a upper support member  51  removeably attached to upper front horizontal member  14  by hooks  60  and integrally attached to upper rear horizontal member  17 ; side wall netting  80 ; bottom wall netting  90 ; lower supporting members  52 ,  53 ; and expandable members  70  connecting the upper support member  51  to lower supporting member  52 . Furthermore, as discussed in more detail herein below, the rear horizontal support member  17  receives or is integrated with an inner frame  50  such that the inner frame is operative to pivot about upper rear horizontal support member  17 . 
         [0027]    To form the side walls of the inner frame, the expandable inner frame is constructed with soft (e.g., fabric or non-metallic) side walls and a bottom wall supported by one or more metal support members. The advantages of a non-metallic material include the feature of eliminating the possibility of fingers or items being crushed by the collapsing sidewall because, unlike metal rods, a non-metallic sidewall will yield. As shown in the figures, the preferred inner frame of the present invention comprises side wall netting  80  attached to upper support member  51  and lower support members  52 ,  53 . 
         [0028]    To hold the flexible side wall netting apart, lower support members  52 ,  53  are preferably of the same dimensions as upper support member  51 . The side wall netting  80  is securely attached to upper support member  51  so as to provide support for the netting when items are placed with the inner frame, whereas side wall netting  80  may be less rigidly attached to lower support member  52  merely to maintain the position of side wall netting  80 . Lower support member  53 , which is preferably the same dimensions as members  51 ,  52 , is attached to the bottom of netting  80 . The attachment of netting  80  to support member  53  is more secure than the attachment of netting  80  to support member  52  in order to provide support when items are put in the netting. A bottom wall  90  that is lightweight and firm is attached to lower support  53 . Bottom wall  90  may be comprised of rigid plastic or metal mesh. Although three frames are shown in the figures, there may be any number of stages with frames vertically suspended from one to the next. 
         [0029]    First lower support member  52  is suspended from upper support member  51  by expandable members  70 , which are preferably elastomeric cords. In an alternative construction, the lower support member  52  is suspended from upper support member  51  by larger, expandable segments, such as elastomeric mesh, which may or may not be integrated with side wall  80 . 
         [0030]    Side wall netting  80  may be tethered to at least a part of the outer frame and supplimentally supported thereby. There may also be a flexible pocket or pouch  100  attached to upper rear horizontal support member  17  and hanging outside the receptacle formed by frames  51 - 53  and netting  80 , as best shown in  FIG. 1C . The pocket or pouch  100  is attached at its upper end so it may be lifted up as shown in  FIG. 2 . 
         [0031]    Referring to  FIGS. 6 ,  7 , and  8 , since it is not unusual to see a shopping cart moving voluntarily due to uneven surfaces or an unintentional force applied to the device when it is parked or left unattended, a shopping cart according to the present invention may be provided with a brake assembly  250  configured to arrest the movement of the device when it is not in use. 
         [0032]    An actuating component including a brake handle  256  and a transmission element is coupled under handle  16  to the outer frame. In accordance with one aspect, the transmission component has an elongated member  258 , which may be, e.g., a flexible wire or rigid rod, attached between brake handle  256  and rod  259 . In a rest or parking state, the cable is resiliently biased downwardly to have a pad assembly, as will be explained in reference to  FIGS. 8 and 9 , firmly abut a respective one of wheels. As the device user applies a squeezing force to brake handle  256 , which pivots upwardly, the elongated member is tensioned or pulled and the pad assembly is lifted, thereby releasing the wheels. The break mechanism is preferably designed to default to an on/engaged position preventing unintentional cart motion. 
         [0033]    It will be recognized by those of skill in the art that, as the break system defaults in an on position, it would be convenient to have a break disengagement system available at the front of the cart. This particular system would provide main benefit where a cart user is positioned in front of the cart and needs to pull a fully loaded cart forward. Rather than dragging the cart against the break system friction, the user may simply disengage the break system. Such a front-end disengagement system may be readily provided via a flexible cable release system (similar to element  258 ) with a release handle at the front (not shown) 
         [0034]      FIGS. 7 and 8  illustrate the pad assembly including a brake housing or casing  262  enveloping the lower end of rods  259 , brake pad  264 , which has a lower segment shaped complementary to wheel  74 , resilient element  266 , and inverted T-shaped bushing  268 , which centers rod  259  within housing  262 . In the parking state, resilient elements  266  biases the pad assembly downwardly enabling, thus the lower segment of brake pad  264  to abut the wheel. A rate of resilient elements is so selected that the device user typically does not apply a substantial force. However, the spring rate is sufficient for the resilient element to reliably press brake pad  264  against the wheel. While the upper end of rods  259  is centered by T-shaped bushings  268 , the lower end of these rods is formed with an enlarged ball  270  preventing disengagement of the rods from the pad. 
         [0035]    The pad assembly disclosed above is exemplary and can be modified. For example, instead of the springs, brake assembly  250  may be provided with a pneumatic means. Still a further alternative configuration can include a hydraulic means. Both aspects can be readily adapted by ordinary skilled workers. 
         [0036]    As is known, shopping cards are conventionally provided with a secured or temporarily-removable child seat. As shown in  FIG. 6 , a preferred shopping cart according to the present invention comprises a seat  300  pivotally mounted on upper rear horizontal support member  17 . When in use, seat  300  is swung into the inner frame, as shown in solid lines in  FIG. 6 ; otherwise, seat  300  may be pivoted in a position shown in phantom lines. Pivoting to the lifted position can, of course, be performed by the device user, or by the distal end of a subsequent device that, thus, fits into the opening typically closed by the back of seat  300 . 
         [0037]    In the embodiment shown in the figures, the child seat comprises a flexible hammock supported by a bar. The bar may be moved from an open position to a closed position along slots provided at the top of the basket. The use of the flexible hammock child seat reduces the ability of a child riding in the seat to gain leverage and lift out of the seat. The child seat may optionally include a safety belt (not shown). For example, the safety belt may be generally Y shaped with two points of securement on the bar and one point of securement on the rear wall of the cart, between the child&#39;s legs. Although the child seat shown in the figures comprises a flexible hammock, any other suitable type of child seat may optionally be used. 
         [0038]    The shopping cart of the present invention can be collapsed as shown in  FIGS. 3A-3C . The collapsing is done by disengaging the expandable inner frame from the collapsible outer frame, and collapsing or folding the outer frame as designed. As shown, the preferred embodiment is collapsed by: disengaging support member  51  from upper front horizontal member  14  by lifting hooks  60  from upper front horizontal support member  14 ; moving upper front horizontal support member  14  forward so that hooks  60  are clear there from; pivoting the now-freed inner frame about upper rear horizontal support member  17 , such that the inner frame hangs down from upper rear horizontal support member  17 , as shown in FIGS.  3 A- 3 C; rotating side members  11 ,  12  relative to each other, such that the upper horizontal support members  14 ,  17  are brought substantially together and such that side members  11 ,  12  are substantially parallel; whereby the entire shopping cart is collapsed into a small space as shown in  FIG. 4 . 
         [0039]    The safety strap  110 , as shown in  FIG. 3A , that connects the upper horizontal support members  15 ,  17  keep the outer frame from awkwardly flopping while the inner frame is collapsed, but the outer frame is not yet folded. The closure  120  keeps the outer frame positioned in its collapsed position. As shown, a preferred closure  120  comprises two magnets, one magnet on each of crossing members  11  and  12 , as shown in  FIG. 5 . 
         [0040]    A transportation device according to the present invention may be particularly suitable for commercial and/or industrial use. A commercial and/or industrial transportation device according to the present invention may be made with stronger frame members, reinforced mesh, and other similarly reinforced materials. 
         [0041]    This application describes the inventive transportation device for illustration purposes only. Neither the specific embodiments of the invention as a whole, nor those of its features limit the general principles underlying the invention. The specific features described herein may be used in some embodiments, but not in others, without departure from the spirit and scope of the invention as set forth. Many additional aspects are intended in the foregoing disclosure, and it will be appreciated by those of ordinary skill in the art that in some instances some features of the invention will be employed in the absence of a corresponding use of other features. The illustrative examples therefore do not define the metes and bounds of the invention and the legal protection afforded the invention, which function is served by the claims and their equivalents.