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US 4,510,116 AGranted
Apparatus and method for blow molding
AssigneePhillips Petroleum Company
InventorsDonald L. Peters, John R. Rathman, Irvin L. Sumpter
Life of this patent
Estimating the term…
Abstract
In blow molding an article with a reverse fold, a profiled bar is positioned where the parting line of the mold is to be when the mold is closed. The bar provides a reverse fold in the plastic article during a pre-blow step. In operation, a pre-pinched parison is formed adjacent the bar and as the mold begins to close a small amount of pre-blow air is introduced into the parison folding it against and over the bar. After the mold is closed, blow air is introduced to form the part. A complex part with good wall distribution of material can be obtained by this method.
Claims10
Apparatus comprising
- a means for extruding a molten tubular parison from between a die and a ring into a closeable mold, said tubular parison to have a first end attached to said means and a second end;
- a means for pinching closed the second end of the tubular parison prior to closing the mold;
- a means for pneumatically pre-expanding the parison prior to closing the mold;
- said closeable mold, when in the closed position, defining a chamber with at least one longitudinally extending rib protruding inwardly from the sidewall of the chamber in the range of from 2 to about 25 percent across the chamber;
- said closeable mold comprising a first mold part which determines the rib, said first mold part having a first face and a second face;
- a second mold part which determines a first side portion of the chamber, said second mold part having a first face and a second face;
- and
- a third mold part which determines a second side portion of the chamber, said third mold part having a first face and a second face;
- the first face of the first mold part matching with the first face of the second mold part and the second face of the first mold part matching with the first face of the third mold part;
- a means for providing a closure between the second face of the second mold part and the second face of the third mold part;
- a means for moving the second mold part into a position so that the first face of the second mold part matches with the first face of the first mold part;
- and
- a means for moving the third mold part into a position so that the first face of the third mold part matches the second face of the first mold part.
10 more elements
Apparatus comprising
- a means for extruding a molten tubular parison from between a die and a ring into a closeable mold, said tubular parison to have a first end attached to said means and a second end;
- a means for pinching closed the second end of the tubular parison prior to closing the mold;
- a means for pneumatically pre-expanding the parison prior to closing the mold;
- said closeable mold, when in the closed position, defining a chamber with at least one longitudinally extending rib protruding inwardly from the sidewall of the chamber in the range of from 2 to about 25 percent across the chamber;
- said closeable mold comprising a first mold part which determines the rib, said first mold part having a first face and a second face wherein the first mold part is fixedly mounted with respect to the means for extruding the molten tubular parison;
- a second mold part which determines a first side portion of the chamber, said second mold part having a first face and a second face;
- and
- a third mold part which determines a second side portion of the chamber, said third mold part having a first face and a second face;
- the first face of the first mold part matching with the first face of the second mold part and the second face of the first mold part matching with the first face of the third mold part wherein the second face of the second mold part matches with the second face of the third mold part to provide a closure between the second mold part and the third mold part;
- a means for moving the second mold part into a position so that the first face of the second mold part matches with the first face of the first mold part;
- and
- a means for moving the third mold part into a position so that the first face of the third mold part matches the second face of the first mold part.
9 more elements
A method for blow molding a plastic article from a parison comprising
- extruding a molten tubular parison along the side of an elongated rib, said rib to be positioned along the parting line of a pair of mold parts to form a chamber having an inwardly protruding rib extending partway thereacross and then pinching shut the open end of the parison;
- thereafter pneumatically expanding the parison partially around the elongated rib;
- then moving the mold parts into contact with the elongated rib while pinching a flash line of said parison between the elongated rib and the mold parts;
- and
- pneumatically expanding the inside of the parison to fit the chamber defined by the mold parts and the elongated rib.
2 more elements
Dependencies are inferred from the claim text.