Patent ID: 8011157

Claim:
A grating assembly having longitudinal and axial directions comprising: a plurality of axially spaced metal longitudinal deep bars; a plurality of longitudinally spaced metal axial crossbars each having a top and bottom defining therebetween a first height; a plurality of longitudinally spaced metal axial filler bars each having a top and bottom defining therebetween a second height which is less than the first height; wherein the deep bars are part of a first grating subassembly; the crossbars and filler bars are part of a second grating subassembly; the second subassembly has unjoined and joined positions in which it is respectively separate from and joined to the first subassembly; the second subassembly is movable downwardly from the unjoined position to the joined position where it rests on top of the first subassembly; and the tops of the crossbars are substantially flush with the tops of the filler bars in the joined position.