Utility cart

Land vehicles – Wheeled – Stable vehicles – handle-propelled

Reexamination Certificate

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Details

C280S651000, C280S079300, C211S126400

Reexamination Certificate

active

06213483

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to utility carts. The present invention relates more specifically to utility carts for transporting and/or bussing.
BACKGROUND OF THE INVENTION
Utility carts are used in a variety of commercial and residential applications, including commercial kitchen and food preparation applications. These utility carts typically include a top shelf, a bottom shelf, four legs, a pushing handle, and a plurality of wheels or casters attached to the bottom shelf or to a base. The shelves are typically attached to the legs by rivets, screws or welds.
These conventional utility carts have varying load capacities. One standard test for load capacity is to run the cart, fully-loaded, diagonally over a threshold. The threshold is, for example, a five-eighths inch high block of wood anchored to the floor. The cart is run back and forth over the threshold repeatedly until failure. If the cart withstands a predetermined number of runs with a given load without failing, the given load is the load capacity of the cart. While various load capacities have been used to classify “heavy duty”, “medium duty”, and “standard duty” carts, for purposes herein, heavy duty shall mean a capacity of approximately 650 pounds or more, medium duty shall mean a capacity of approximately 400 pounds, and standard duty shall mean a capacity of approximately 200-300 pounds.
Heavy duty carts are similar to standard duty and medium duty carts, except that design modifications provide for the increased weight capacity. One important design modification is that many of the components must be arc welded together to improve the strength and durability of the cart. For example, the shelves of heavy duty carts are arc welded to the legs.
One drawback of known heavy duty carts is that the arc welding process is a costly one, driving up the price of the cart for the consumer. Arc welding requires skilled labor and several welding steps, including polishing and refinishing.
A second drawback of known heavy duty carts is that they must be shipped in their assembled or substantially assembled state due to the components being arc welded together. To reach some markets (e.g., overseas markets), shipping costs are calculated based on the volume of the items shipped. Thus, shipping a cart in its assembled state can become costly and preclude entry in these markets. A knocked-down (i.e., shipped un assembled) cart can be shipped in approximately one-half to one-third the volume of a comparable assembled cart. Thus, a heavy duty knocked-down cart could open up significant markets where previous assembled carts were not competitively priced. However, it was previously thought impractical to design a metal cart which did not rely on arc welding for its rigidity.
Conventional knocked-down carts have drawbacks as well. These carts often have a large number of assemble able parts, e.g., screws, bolts, shelves, wheels, axles, legs, etc. Furthermore, they tend to be expensive and can lack the necessary strength required for larger loads.
Thus, it would be advantageous, though previously thought unattainable, to provide a heavy duty knocked-down cart, i.e., one that could be reduced in size for shipping, that maintains the strength and durability of a heavy duty cart and also is easy to assemble by the user. It would also be advantageous to provide a heavy duty, medium duty or standard duty cart having a simpler design to provide a more economical utility cart. More specifically, it would be advantageous to provide a heavy duty, medium duty or standard duty cart substantially free of arc welds to provide a more economical utility cart. Also, it would be advantageous to provide various design modifications to a standard utility cart to improve its strength and durability. Additionally, it would be advantageous to provide a knocked-down cart that is easily assemble able by an unskilled user.
SUMMARY OF THE INVENTION
The foregoing limitations of prior utility carts have been overcome by the present invention in its various embodiments, in which, according to one embodiment, a utility cart is provided having a frame, a plurality of wheels rotatably coupled to the frame, and a shelf supported by the frame. One of the frame and the shelf includes a retention surface and the other of the frame and the shelf includes a movable surface. The movable surface is configured to move between a first position out of engagement with the retention surface and a second position in engagement with the first retention surface to mount the first shelf to the frame. The movable surface is resiliently biased in the second position.
According to another embodiment of the present invention, a utility cart is provided having a frame with first and second spaced vertical members. The utility cart has a cross member connecting the first and second vertical members. One of the cross member and the first vertical member includes a protuberance terminating at an enlarged head, and the other of the cross member and the first vertical member includes a slot receiving the protuberance to connect the cross member to the first vertical member.
According to yet another embodiment of the present invention, a utility cart is provided having first and second substantially rigid members and a third substantially rigid member extending between and connecting the first and second rigid members. The utility cart includes a first shelf coupled between the first and second rigid members and spaced from the third rigid member by a first distance and a second shelf coupled between the first and second rigid members and spaced from the third rigid member by a second distance greater than the first distance. The second shelf is configured to deflect at least one of the first and second rigid members to apply a binding force upon the first shelf.
According to still another embodiment of the present invention, a utility cart is provided having first and second substantially rigid members and a third substantially rigid member extending between and connecting the first and second rigid members. The utility cart includes a first shelf coupled between the first and second rigid members. The first shelf and the first rigid member are coupled together to define a distance between the first and second rigid members at a location at which the second shelf is to be attached. The length of the second shelf at the location of attachment is different than the distance.
According to one aspect of this embodiment, the rigid members comprise a substantially U-shaped leg member.


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