Injection mold seat riser for modular school bus seats

1. A riser assembly for a modular seat frame for a school bus comprising:

a riser formed of a moldable material and having a major face;

a plurality of support ribs disposed on the major face and defining the major face as an interior face;

a riser extension including an open trough for locating one end of a seat back frame member and providing a point of attachment for one end of the seat back frame member; and

at least a first neck reinforcement member for installation on the riser at the point of attachment, said at least first neck reinforcement member including a tube section which fits snugly in the open trough to reinforce the open trough of the riser extension and a gusset depending from an end of the tube section which fits against the support ribs of the interior face; and

the tube section of the first neck reinforcement member being shaped to mate with the one end of the seat back.

2. A riser assembly as claimed in claim 1 , further comprising:

the support ribs being divided into first and second sets, the support ribs of the first set being mutually parallel to one another and orthogonal to the ribs of the second set.

3. A modular seat frame comprising:

a riser assembly including a riser formed of a moldable material and having a major face bearing a plurality of support ribs;

an open trough extending from the riser assembly to provide a location for attachment of a seat back frame member; and

a neck reinforcement member having a tube section which fits flush in the open trough for reinforcing the riser assembly locally and which allows for mating attachment of the seat back frame member, and a gusset section which is formed to fit against the riser.

4. A modular seat frame as claimed in claim 3 , the riser assembly further comprising:

the plurality of support ribs being divided into two sets, the support ribs of any one set being mutually parallel to one another and the different sets being orthogonal.