Modular athletic playing surface with tuned compliance

Abstract

A closely spaced array of modules forms an athletic playing surface characterized by a high degree of vertical compliance, an extreme resistance to lateral shear, and a high degree of uniformity of response. Each module has a laminated construction that includes a pair of stiffly resilient plates in a generally parallel, spaced relationship. One or more spacer plates and a plurality of resilient members are 'sandwiched' between the plates. The lower plate is supported on a frame that allows it to flex in response to an applied force, typically the impact of a runner's foot on the upper plate. The spacer plate is configured, positioned, and secured to the upper and lower plates to mechanically couple them in a manner that, to a large degree, compensates for a non-uniformity of the deflection response of the module introduced by the frame support. The resilient members are selected and positioned to provide a substantially uniform deflection response at the upper plate. In the preferred form, the module has a set of hold-down bolts that extend between the upper and lower plates at points remote from the spacer plate or plates. The bolts limit the maximum vertical spacing between the plates and provide a convenient adjustment of both the vertical compliance of the module and the level of the upper plate. Also, the edges of adjacent upper plates preferably carry a set of control tabs, each secured to one plate and extending under the adjacent plate, to control the maximum vertical displacement between the adjacent edges.