Open floor grating

Claim 1

AN OPEN FLOOR GRATING FOR SUPPORTING VEHICULAR TRAFFIC COMPRISING A PLURALITY OF SPACED GENERALLY PARALLEL BARS EXTENDING TRANSVERSELY OF THE DIRECTION OF TRAVEL OF TRAFFIC, A PLURALITY OF SPACED SUBSTANTIALLY PARALLEL SECONDARY BARS EXTENDING BETWEEN SAID PRIMARY BARS AT AN ANGLE OF BETWEEN 15 AND 45* TO THE DIRECTION OF TRAFFIC, AND TERTIARY BARS EXTENDING BETWEEN AND FASTENED TO SAID SECONDARY BARS BETWEEN SAID PRIMARY BARS IN NON-PARALLEL RELATIONSHIP WITH SAID PRIMARY BARS, THE TOPS OF SAID BARS BEING IN SUBSTANTIALLY THE SAME HORIZONTAL PLANE, ALL OF THE LOAD SUPPORTING SURFACES OF SAID GRATING BEING DISPOSED AT AN ANGLE TO THE DIRECTION OF TRAVEL OF SAID TRAFFIC AND THE MAJORITY OF SAID SURFACES BEING ARRANGED AT A NON-PERPENDICULAR ANGLE TO THE DIRECTION OF TRAVEL OF SAID TRAFFIC, SAID BARS FORMING A PLURALITY OF OPENINGS HAVING A PLURALITY OF DIFFERENT SHAPES.