Abstract: A blow molding machine is disclosed for hollow plastic articles. The machine includes a clamp mechanism for a pair of mold sections. It comprises a body disposed below an extruder at an extruding station and a blow pin at a blow station and carrying opposed platens for supporting the mold sections. Each of a pair of levers is pivotally coupled with a respective platen and with the body and the levers are connected together by a pull bar. An actuating means displaces one of the platens relative to the body and equal and opposite motion is transmitted through the levers and the pull bar to the other platen for opening and closing the clamp. A lifting mechanism supports the clamp for movement between the extruding station and the blow station. The lifting mechanism is adapted for vertical motion by a hydraulic motor acting on a lifting frame. The frame is mounted by pivot links on the machine base and pairs of links are connected by a shaft with a crank arm, the crank arms being connected together by a tie rod.