This application claims priority to U.S. Ser. No. 60/719,774, filed Sep. 20, 2005.
BACKGROUND OF THE INVENTION
 This invention is related to mattress and spring combinations, and in particular to an apparatus that permits the customization of the firmness of the mattress, and also permits the replacement of a worn comfort layer without the need to replace the entire assembly.
 Conventional bedding systems normally consist of a box spring and mattress that are sold and used as a matched set. The mattress (and in some cases the box spring) are built to provide a desired level of firmness in the assembly. The mattress itself normally includes a spring assembly (in addition to that of the box spring) and a "comfort layer" of a cushioning material overlaying the springs. The spring and comfort layer of the mattress are encased in a single, non-removable cover. Wear in the mattress normally occurs first in the comfort layer, and eventually requires the replacement of the entire mattress. Since the springs of the mattress and those of the box spring assembly are normally selected to work in unison, when replacing the mattress it is normally necessary to replace the box spring unit as well. This can be an expensive replacement, particularly in the case of a hotel, for example, which might find it necessary to replace hundreds of mattress/box spring assemblies on a regular basis.
 Conventional mattress and box spring assemblies embody another shortcoming as well. While a customer or user might like the spring selection of a particular mattress/box spring assembly, the particular comfort layer might not be to the user's liking. This could occur in at least two situations. First in the instance of a hotel, the bed in a particular room might not be the first choice or most comfortable for a customer. While some hotels offer a limited choice of different beds, each is in a particular room, and if taken offers no flexibility to the hotel or the customer. Second, retailers are required to maintain a selection of models in inventory, but with all the possible combinations of box springs and mattresses available, the retailer must either keep an extensive inventory of different combinations, or risk not having that which the customer prefers. In addition, most returns of bedding to retailers are the result of the customer having made a bad choice in the firmness of the comfort layer of the mattress. The return of mattresses represents a significant cost for retailers and manufacturers alike. A mattress technology that effectively addressed these problems would be a welcome improvement in the industry. The present invention addresses these shortcomings and problems associated with the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
 FIG. 1 is a perspective view of the invention showing an assembled bedding system according to a preferred embodiment of the invention.
 FIG. 2 is a partial exploded view of the invention showing a spring, a foundation and a replaceable top comfort layer according to the invention.
 FIG. 3 is a partial cross-sectional view of the embodiment shown in FIG. 1.
 Referring now to the drawings, a preferred embodiment of the invention is shown generally at 10, and includes a conventional box spring 12 and a novel support/comfort layer assembly 14. Referring now to FIGS. 2-3, support/comfort layer assembly 14 includes a support base 16 and a separate comfort layer 18, both of which are encased in a removable cover 20. The assembly rests atop the box spring according to conventional practice. However, in the present invention the comfort layer 18 can be readily removed and replaced by simply removing cover 20 and disengaging several hook and loop or other fasteners, exposing the comfort layer 18. This feature enables the matching of a desired comfort layer 18 on any bed assembly made according to the invention. For example, a hotel could replace a worn comfort layer and cover without the need to replace the support base and box spring, saving a significant expense since the comfort layer represents a relatively modest cost compared to the replacement of an entire conventional box spring/mattress assembly. In addition, a hotel using the invention could offer any customer a choice of comfort layer options in literally every room of the hotel by stocking a variety or comfort layers of differing firmnesses and thicknesses.
 In the case of a retailer, one now only needs to display a relatively few box spring and support base combinations, all of which could be quickly topped with a selection of comfort layers to demonstrate the choices available to a customer. In addition, if after trying a variety of comfort layers the customer nonetheless wishes to change the feel of the bed, the customer's wishes can be accommodated by merely replacing the comfort layer rather than the entire bed, representing a significant saving and convenience for both the retailer and the customer.
 In a preferred method of commercializing the invention, the assembly would be offered in a plurality of comfort layer options, including but not limited to extra firm, firm, plush firm, plush, plush pillow top, plush eurotop, and memory foam. Support bases would be offered in several forms reflecting perhaps different firmnesses and quality of components--good, better and best, and regular height and low profile box springs ranging in heights between 9'' and 5''.
 While the invention has been described by reference to preferred embodiments described above, those of skill in the art will recognize that the invention could be modified in arrangement and detail without departing from the scope of the invention as broadly described.