Blow molding machine

Claim 1

Machine for the manufacture of blown hollow articles of plastics material, said articles having neck and body portions, comprising a. a frame structure, b. carriage means mounted for movement along a horizontal rectilinear path on said frame structure and carrying i. a plastics extruder connected with an extrusion nozzle comprising an annular die having its axis directed vertically downwards and a central core for extruding a plastics tube, said core having an air passage therethrough and opening through the bottom thereof, ii. first and second cylinders respectively actuating first and second piston rods for movement in a vertical direction relative to the carriage means and along axes which are respectively spaced by equal distances from and on opposite sides of the axis of said extrusion nozzle, each said piston rod having an air passage therethrough and opening through the bottom thereof, iii. a cutting device moveable relative to the carriage and below said extrusion nozzle for severing the plastics tube extruded through said nozzle, and iv. means for moving said cutting device, c. means for moving said carriage means back and forth on said frame structure along said path to move said extrusion nozzle between a first extrusion station and a second extrusion station spaced apart by a predetermined distance equal to the distance between the axis of either of said piston rods and the axis of said nozzle, d. a central platen and first and second outer platens mounted on said frame structure below said carriage and having surfaces to which halves of a split blow-mold are adapted to be secured, said platens being spaced apart with the said surfaces of the platens parallel to each other, the central platen being adapted to carry a mold half on each of its surfaces facing an outer platen and each outer platen being adapted to carry a mold half on its surface facing the central platen, said platens being mounted for movement in a horizontal rectilinear path perpendicular to said surfaces and parallel to the path of movement of said carriage means, e. means for moving said outer platens simultaneously in the same direction and said central platen in the direction opposite to the instant direction of movement of said outer platens whereby a first pair of mold halves between said first outer platen and the central platen will be opened simultaneously with the closure of a second pair of mold halves between said second outer platen and the central platen, and vice versa, the arrangement being such that when said first and second pairs of mold halves are closed they are respectively aligned with the extrusion nozzle when positioned in said first extrusion station and said second extrusion station respectively, and f. means for selectively admitting blowing air to the air passages in said core and said piston rods.