Moulding unit for a plant for blow-moulding plastic containers, particularly bottles
AssigneeSacmi Cooperativa Meccanici Imola Societa' Cooperativa
InventorsMaurizio Borgatti, Massimo Morovingi, Fiorenzo Parrinello, Emilio Re, Gabriele Stocchi
Life of this patent
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Abstract
A molding unit for a plant for blow-molding plastic containers (2), particularly bottles, from respective parisons (3) is equipped with an interchangeable mold (16) having at least one cavity (19) for blow-molding a respective container (2), and at least two stretching rods (33) mobile along a predetermined line (24) to engage respective parisons (3) and to axially deform the parisons (3) themselves; the stretching rods (33) being selectively mobile according to the number and/or position of the molding cavities (19) of the mold (16) mounted on the molding unit at a given time.
Claims14
A blow-moulding unit for making plastic containers (2) from respective parisons (3), and comprising:
- a mould (16) having at least one cavity (19) for blow-moulding a respective container (2) and being interchangeable with another mould (16) having a different number of moulding cavities 19);
- a mounting frame (34);
- at least two stretching rods (33) coupled to the mounting frame (34) to move along a longitudinal line (24) along which the rods themselves extend so as to engage and longitudinally deform respective parisons (3) housed in the at least one moulding cavity (19);
- a mounting slider (35) designed to be coupled to the stretching rods (33) and which is movable longitudinally relative to the mounting frame (34) and connected to an actuator (37) that longitudinally moves the stretching rods (33) coupled to it;
- fastening means for fixing a sub-assembly of the at least two rods (33) to the frame (34) in a raised position where it does not interfere with the parisons (3);
- selective coupling means for connecting to the slider (35) the remaining rods located in a lowered operating position, leaving the slider (35) free to slide longitudinally relative to the rods of said sub-assembly.
A method for changing over a plant for blow-moulding plastic containers (2) from respective parisons (3), from making containers of one size to making containers of a different size, the method comprising the steps of:
- replacing a first mould (16) having at least one cavity (19) for blow-moulding a respective container (2) with a second mould (16) having a different number of moulding cavities (19);
- adapting a stretching unit having at least two stretching rods (33), designed to be coupled to a mounting frame (34) and movable in a longitudinal line (24) along which the rods themselves extend to engage and longitudinally stretch corresponding parisons (3) housed in the at least one moulding cavity (19), a mounting slide (35) designed to be coupled to the stretching rods (33), movable longitudinally relative to the frame (34) and connected to an actuator (37) so as to longitudinally move the stretching rods (33) coupled to it, and a blow-moulding nozzle integral with the frame (34) and connected to a source of pressurized fluid to be blown into the mould (16) cavities (19) through the passages the nozzle has in a number equal to the number of mould (16) cavities (19),
- wherein the step of adapting the stretching unit comprises the following steps:
- uncoupling the rods (33) from the slider (35);
- longitudinally moving the rods aligned with the moulding cavities of the first mould away from the parisons and fastening the upper ends of said rods to the frame (34) in a raised position where they do not interfere with the parisons (3);
- replacing the blow-moulding nozzle with another blow-moulding nozzle having a number of fluid passages equal to the number of cavities (19) of the second mould (16);
- disengaging the stretching rods (33) aligned with the moulding cavities of the second mould from the frame (34) and moving them longitudinally towards the parisons (3) to a lowered operating position;
- selectively coupling to the slider (35) the rods (33) located in said lowered operating position, leaving the slider (35) free to slide longitudinally relative to the rods located in the raised position.
Dependencies are inferred from the claim text.