This invention generally relates to support rails used in spring assemblies such as bedding foundations, seat assemblies and the like and, more particularly, to metal support rails having improved spring mounting capabilities.
Generally, a box spring assembly includes a rectangularly shaped and horizontally positioned frame above which is supported a mattress support deck. A plurality of spring modules are interposed between the frame and deck to support the deck. At their upper ends, the springs include deck attaching portions which interact with the deck so as to attach the springs to it. At their lower ends, prior springs have typically included a pair of mounting feet for attachment to the frame. A grid-like network of deck wires forms the deck and the grid wires which extend both longitudinally and transversely between a border wire. The support springs yieldably support the deck a predetermined distance above the frame.
Most often, the frame itself is formed with a wood perimeter that defines the sides and ends of the frame. Cross rails transversely span the width of the frame and are formed out of either metal or wood. Depending on the type of cross rail, the mounting feet of the springs are secured to the cross rails by various methods. If the cross rail is wooden, the mounting feet of the springs are generally stapled in place on the cross rail. If the cross rail is constructed from metal, each mounting foot is typically provided with a U-shaped horizontal wire portion that is transversely inserted into a slot defined in the cross rail.
While most formed wire springs have had two opposed yieldable portions, each with a mounting foot at its lower end, newer varieties of the formed wire springs have been constructed with only a single mounting foot integrally formed with both of the yieldable portions. One such spring is disclosed in U.S. Pat. No. 5,176,367. This patent is commonly assigned to the assignee of the present application. These springs, however, do not readily lend themselves to mounting with metal cross rails. As is evident from the '367 patent, that design is easily and efficiently mounted to a frame having wooden cross rails through the use of staples. This mounting method has proven satisfactory but, obviously, it is not feasible with metal cross rails which are often desired because of their increased rigidity.
One current trend in the industry is to minimize the amount of assembly required by the end manufacturer while still maximizing space during the shipping of components to that facility. A further trend is to decrease the number of fasteners and variety of springs utilized in the assembly.
In the '367 patent mentioned above, the springs are capable of being mounted to the support deck without fasteners and prior to shipping to the final assembler. Shipping is maximized because the specific construction of the springs was designed so that the deck/spring combination could be stacked and nested within similar deck/spring combinations. One principal element which permits the stacking and nesting of the deck/spring combinations is the V-shape of the springs themselves. This is not readily achievable when the springs have mounting feet on the lower ends of each yieldable section. The present invention, however, can be utilized with either variety of spring.