Importance

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Abstract

A floor panel having a substantially planar upper tread surface comprises a cast grating having first and second pairs of substantially planar, external sidewalls with upper side edges of the sidewalls approximately coinciding with the upper tread surface; a plurality of substantially planar ribs extending from the first pair of opposite sidewalls across the frame, and being spaced apart from each other; a plurality of substantially planar cross ribs extending from the second pair of opposite sidewalls across the frame, and further being spaced apart from each other and forming common intersections with the ribs; wherein the ribs and cross ribs form subdomains between intersections of the respective ribs and cross ribs, the ribs and cross ribs contained within one of said subdomains being left out to form an opening through the floor panel which is larger in size than other openings representing smaller subdomains within the floor panel, said larger opening including a perimeter notch formed at an upper edge of the ribs and cross ribs which form the larger opening, said notch facing inward toward that opening; and a plate having a peripheral edge that fits into the perimeter notch of the larger opening created by absence of the ribs and cross ribs of the subdomain and including means for removal of the plate to facilitate installation of a utility box.

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First Claim