Blow moulding method
AssigneeSupreme Casting & Tooling
InventorSteve A. Kovacs
Life of this patent
Estimating the term…
Abstract
The disclosure relates to a method and apparatus for blow moulding hollow plastic articles each having at an end thereof, a main opening and a secondary opening defined by an angled passageway. The method includes the step of laterally stretching a tubular parison from which the article is to be moulded so as to receive a primary mandrel for forming said opening and a secondary mandrel for forming the passageway. Air is introduced into the parison through the secondary mandrel to form the inner end portion of the passageway while the parison is expanded to conform to the shape of the mould.
Claims5
A method of blow moulding a plastic article having a hollow body portion which defines an internal space, a main opening at an end of said portion communicating with said space and extending about a first axis, and a passageway defining a secondary opening adjacent said main opening, said passageway including an outer portion which extends about a second axis spaced from and generally parallel to said first axis, and an inner portion which is inclined inwardly towards said first axis and communicates with said internal space,
- the method comprising the steps of:
- providing a partible mould comprising mould parts which can be opened and closed and which, when closed, define a mould cavity of a shape appropriate to the required external shape of the article and extending about a longitudinal axis corresponding to said first axis of the article;
- with said mould parts open, positioning between said parts generally on said longitudinal axis, a tubular parison of a thermoplastic material in a mouldable condition, said parison including an end portion at which said main and secondary openings of the article are to be formed and having a radial dimension less than the spacing between said first and second axes of the article;
- providing a primary mandrel and a secondary mandrel shaped to form respectively said main opening and the outer portion of said passageway in the article to be moulded, said mandrels being disposed respectively on said longitudinal axis and a secondary axis corresponding to said second axis of the article, and said secondary mandrel having an air duct which includes an air outlet disposed at an outer end of the mandrel and arranged so that air leaving said outlet in use will form said inner end portion of the passageway;
- laterally stretching said end portion of the parison to an extent sufficient to permit said mandrels to enter said portion, by both radially expanding said end portion and laterally distorting said portion at the position of said secondary axis along which the secondary mandrel is movable;
- moving said mandrels respectively along said longitudinal axis and said secondary axis into said end portion of the parison;
- closing the mould parts about said mandrels and closing the end of the parison opposite said one end;
- introducing air into the interior of the parison to cause the parison to expand and adopt the shape of the mould cavity, including causing air to flow into the parison by way of said air duct in the secondary mandrel, whereby said inner end portion of the passageway is formed by air flowing from said duct into the internal space in the body portion of the article;
- allowing the parison to cool at least to a semi-rigid state in which it can be handled;
- and,
- opening the mould parts to permit removal of the moulded article.
A method of blow moulding a plastic article having a hollow body portion which defines an internal space, a main opening at an end of said portion communicating with said space and extending about an axis, and a secondary opening disposed adjacent said main opening, and communicating with said internal space,
- the method comprising the steps of:
- providing a partible mould comprising mould parts which can be opened and closed and which, when closed, define a mould cavity of a shape appropriate to the required external shape of the article and extending about a longitudinal axis corresponding to said axis of the article;
- with said mould parts open, positioning between said parts generally on said longitudinal axis, a relatively narrow tubular parison of a thermoplastic material in a mouldable condition, said parison including an end portion at which said main and secondary openings of the article are to be formed;
- providing a primary mandrel and a secondary mandrel shaped to form respectively said main and secondary openings, said secondary mandrel having an air duct which includes an air outlet disposed at an outer end of the mandrel;
- laterally stretching said end portion of the parison to an extent sufficient to permit said mandrels to enter said portion, by both radially expanding said end portion and laterally distorting said portion at the position at which said secondary mandrel is to enter said portion;
- moving said mandrels into said end portion of the parison;
- closing the mould parts about said mandrels and closing the end of the parison opposite said one end;
- introducing air into the interior of the parison to cause the parison to expand and adopt the shape of the mould cavity, including causing air to flow into the parison by way of said air duct in the secondary mandrel, whereby air flows from said duct into the internal space in the body portion of the article and ensures communication between said secondary opening and said internal space;
- allowing the parison to cool at least to a semi-rigid state in which it can be handled;
- and,
- opening the mould parts to permit removal of the moulded article.
Dependencies are inferred from the claim text.