Reduced weight fifth wheel assembly

A support structure mounted to a cast-steel bearing plate for a fifth wheel assembly,

• said bearing plate having a lower surface, an upper surface, an outer perimeter, a first planar bearing area to contact a trailer wear plate, a first longitudinal length, a forward edge and a rearward edge along said longitudinal axis, an outer perimeter, and a jaw opening generally centrally located on said bearing plate,
• a first trailer ramp and a second trailer ramp downwardly sloped and narrowingly tapered rearward generally along said longitudinal length from said rearward edge,
• each said first and second trailer ramp having an outer ramp-perimeter merging with said plate outer perimeter,
• a kingpin receiving groove for receipt of an engaging trailer kingpin, said groove generally defined between said first ramp and said second ramp and extending into said jaw opening along said longitudinal length,
• a center recess on said upper surface,
• a first mounting bracket and a second mounting bracket mounted on said lower surface at opposite sides of said plate outer perimeter generally along said transverse axis, each said first and second mounting bracket having a forward side and a rearward side,
• said support structure comprising:
• a plurality of support ribs,
• one of said support ribs being a transverse supporting rib generally extending across said lower surface approximately between said first and second mounting bracket rearward sides to contact said plate outer perimeter in proximity to said first and second mounting brackets at a first intersection and a second intersection, respectively,
• a first longitudinal inner supporting rib rearwardly extending from said transverse rib at one of said first and second bracket rearward sides and merging with one said first and second ramp outer perimeters, a second longitudinal inner supporting rib rearwardly extending from said transverse rib at the other of said first and second bracket rearward sides and merging with the other of said first and second ramp outer perimeters, each said first and second longitudinal inner ribs inwardly displaced on said lower surface along said transverse rib a predetermined distance from said plate outer perimeter,
• a first longitudinal outer reinforcing rib generally extending rearwardly along said plate outer perimeter from one of said first and second transverse rib intersections with said plate outer perimeter, and a second longitudinal outer reinforcing rib generally extending rearwardly along said plate outer perimeter from the other of said first and second transverse rib intersections with said plate outer perimeter,
• said first outer reinforcing rib generally extending along said plate outer perimeter to intersect one of said first and second ramp outer perimeters at said merger of said respective one of said first and second longitudinal support ribs with one of said first and second ramp perimeters, and said second outer reinforcing rib generally extending along said plate outer perimeter to intersect the other of said first and second ramp outer perimeters at said merger of said other of said first and second longitudinal supporting ribs with the other of said first and second outer ramp perimeters,
• said transverse rib, said first longitudinal inner rib and the respective one of said first and second reinforcing ribs cooperating to define a first pocket at said lower surface in proximity to said plate outer perimeter and one of said first and second mounting brackets, and said second longitudinal inner rib, said transverse rib and the other of said first and second reinforcing ribs cooperating to define a second pocket at said lower surface in proximity to said plate outer perimeter and the other of said first and second mounting brackets, said reinforcing ribs providing lateral support to said plate and longitudinal ribs to inhibit lateral deflection of said plate outer perimeter at said first ramp outer perimeter and said second ramp outer perimeter against vertical loads on said plate surface.