Patent ID: 7565868

Claim:
A steel frame for a rig mat, comprising: a rectangular grid of wide flanged steel I-beams comprising longitudinally extending beams and transversely extending cross beams, each beam having a web and top and bottom flanges; each cross beam having end portions welded to an adjacent pair of longitudinally extending beams to form junctions therewith; a pair of upright rectangular gusset plates associated with each cross beam end portion, each gusset plate having top, bottom and end edges, said top and bottom edges being welded to the flanges of the cross beam end portion so as to combine therewith to form an end portion of square tubing configuration; and the plurality of cross beam end portions, connected with the longitudinally extending beams forming the sides of the grid, include opposed pairs of lift end portions, the top flange of each such lift end portion being set back from the adjacent longitudinally extending beam to form an opening, said lift end portion comprising (i) a pin located in the opening and extending through and being supported by the gusset plates and the web of the end portion; and (ii) a shackle pivotally mounted on the pin.