Dual Workflow Nets: Mixed Control/Data-Flow Representation for Workflow Modeling and Verification

A spring-balanced, wall-type bed-frame member, which is adapted to support a portion of a mattress assembly, is pivotable between a vertical position adjacent a wall and a horizontal position upon a floor for use. A plurality of the frame members are needed to support the mattress assembly for a bed. The bed contains no permanent cross members linking the respective bed-frame members, so that the location of the frame members can be laterally changed to accommodate mattress assemblies of differing widths.