Method and apparatus for making plastic articles

Claim 1

APPARATUS FOR CYCLICALLY FORMING BLOWN HOLLOW ARTICLES FROM PLASTIC MATERIAL, SAID APPARATUS COMPRISING SEPARABLE MOLD MEANS DEFINING A CAVITY, EXTRUSION MEANS FOR CYCLICALLY EXTRUDING A TUBE OF PLASTIC MATERIAL TO BE FORMED IN THE SPACE BETWEEN THE MOLD MEANS, SAID EXTRUSION MEANS COMPRISING AN EXTRUSION CHAMBER HAVING AN END PORTION SLOPING TOWARD AND TERMINATING IN A REDUCED ORIFICE, A FIRST MOVABLE SLEEVE IN SAID CHAMBER AND HAVING AN EXTERNAL DIAMETER LESS THAN THE DIAMETER OF SAID CHAMBER AND AN INTERNAL DIAMETER APPROXIMATELY EQUAL TO THE DIAMETER OF SAID ORIFICE, SAID SLEEVE HAVING A SLOPING END FACE GENERALLY COMPLEMENTARY TO SAID EXTRUSION CHAMBER END PORTION TO PROVIDE AN ANNULAR PLASTIC PASSAGE, AND A SECOND MOVABLE SLEEVE TELESCOPING WITHIN SAID FIRST SLEEVE AND ADAPTED TO COOPERATE WITH SAID EXTRUSION CHAMBER END PORTION TO DEFINE A FURTHER EXTRUSION PASSAGE PORTION, SAID SECOND MOVABLE SLEEVE LIKEWISE HAVING A SLOPING END FACE, AT LEAST ONE OF SAID SLEEVES BEING CYCLICALLY MOVABLE TOWARD AND AWAY FROM SAID CHAMBER END PORTION TO DEFINE VARIABLE ANNULAR EXTRUSION MEANS, AND A CYCLICALLY MOVABLE MANDREL TELESCOPING WITHIN SAID SECOND SLEEVE, SAID SECOND MOVABLE SLEEVE FITTING PERIPHERALLY WITHIN SAID REDUCED ORIFICE WHEREBY MOVEMENT OF SAID SLEEVE INTO SAID ORIFICE SEVERS AN EXTRUDED TUBE FROM THE SUPPLY BODY OF PLASTIC MATERIAL.