Abstract: A rubber injection molding apparatus and method for simultaneously molding a plurality of work parts (40) in separate molds (30) using a single, vertically oriented press machine (22). A clamping mechanism (52) is responsive to the vertical, reciprocating motion of the press ram (26) for converting the generally vertical motion of the press ram (26) into a horizontal clamping force to squeeze and hold the molds while rubber is injected into their cavities (38). The molds (30) each have two mold halves (32, 34) joining one another along a parting line interface (36) with the mold cavity (38) in between. The mold halves (32, 34) are received in universal carriers (62), which in turn are suspended between and slideable along spaced-apart first (58) and second (60) rails. A large number of mold cavities (38) can be filled simultaneously using a vertically oriented press machine (22).