Innerspring assemblies of the aforementioned type are well known within the furniture industry for use in connection with mattresses as well as other forms of upholstered furniture. Characteristically, such innerspring assemblies comprise a plurality of resiliently compressible spring coils arranged in adjacent side-by-side disposition in a selected systematic array, most commonly in linear rows and columns, and connected together, e.g., by metal bands, clips, strings, helical wires, or the like, to form an integrated spring cushion assembly. Such innerspring assemblies used for mattresses also commonly include border rods, which may be continuous or discontinuous, forming a perimeter outwardly about and connected to the upper and lower end turns of the outermost spring coils.
The types, configurations and constructions of the spring coils utilized in such innerspring assemblies are quite diverse and may differ, for example, according to the type and size (gauge) of the wire from which the spring coils are made, the number of intervening coil turns between the opposite end turns (which may be a whole number of turns or may include a one-half coil turn), whether the spring coils are separate wire units or part of a common length of wire, and whether the upper and lower end turns of each spring coil are closed (the terminal wire ends of the spring coil are knotted to a medial point along the end coil) or open (the terminal wire ends are left free and unconnected). With respect to any given innerspring assembly, the selection among these various characteristics for the spring coils is made according to considerations of the desired spring characteristics for the cushion assembly, cost, structural stability and rigidity of the cushion assembly. In particular, the fact of being knotted or open at the upper and lower end turns of each spring coil can have an effect on the overall comfort and feel of the innerspring assembly when used in a mattress.
In the current mattress market, there has been increased demand for one-sided mattresses, which may be maintained in active use without requiring physical flipping of the mattress over the useful life of the mattress. Designs for known one-sided mattresses have focused on adopting changes to the mattress padding or the mattress cover, whereby the bottom surface of the mattress is lightly padded and the top surface includes comfortable padding as a sleep surface. However, in many regards, these variations to the surface characteristics of the mattress do not account for the full range of options and level of comfort expected by customers. Accordingly, there exists a need for a comfortable innerspring assembly that is capable of providing a soft and supportive sleeping surface suited for consistent use as a one-sided mattress.
Furthermore, existing designs for one-sided mattresses have not been able to provide for varying ranges of comfort based on variations in the spring support within the spring cushion assembly across the sleeping surface of the mattress. Such a feature can be expected to have even greater significance to customers who select a mattress based on a preference for differing levels of firmness in certain areas of the mattress, such as might be the case for customers who prefer greater support in the head area of the mattress. Further, many health conditions necessitate that a customer select a mattress that provides differing levels of firmness, such as might be the case for customers with lower back pain who need greater support in the center of the mattress. As a result, there exists a need in this expanding industry to provide an innerspring assembly for a one-sided mattress that meets customer expectations for varying comfort zones.