Grate for a subsurface catch basin

A grate to cover the open top of a catch basin, said grate comprising a hollow, continuous, integral and monolithic body of organic plastic material which has been formed by a rotational molding process, said body comprising:

• a top bearing plate, said top bearing plate having a plurality of spaced apart slots therethrough, said slots being bounded by bars which are an integral part of the top bearing plate, said top plate and grate being generally square-shaped, having four bounding sides, said top bearing plate having a peripheral edge;
• a peripheral rim having an upper and a lower edge, its upper edge joining the lower edge of the top bearing plate;
• a bearing shoulder having an inner and an outer edge extending around all sides of the grate, said top bearing plate, rim and bearing shoulder forming an internal recess, a bearing surface being formed on the bottom of said bearing shoulder, whereby to form an external bearing flange;
• a skirt having an upper and a lower edge, its upper edge joining the inner edge of said bearing shoulder;
• a peripheral base having an inner edge and an outer edge, its outer edge joining the bottom edge of said skirt;
• a peripheral return surface having a lower edge extending upwardly from the inner edge of said peripheral base to join said top bearing plate;
• and
• a cross-beam extending between a pair of said sides, said cross beam having a pair of spaced-apart sidewalls depending from said top bearing plate, each having a lower edge, and a central section joining said bottom edge, thereby forming a beam cavity.