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US 4,859,397 AGranted
Preventing gas leakage around blow needle in blow molding method
AssigneePhillips Petroleum Company
InventorDonald L. Peters
Life of this patent
Estimating the term…
Abstract
Blow molding of a parison with a blow needle is aided by the use of a sealing member which includes at least one projection which completely surrounds the blow needle. During inflation of the parison, the projections come into sealing contact with the exterior surface thereof so as to effectively prevent leakage of blow gas from the interior of the parison around the blow needle.
Claims7
A method of blow molding an article from a parison comprising:
- (a) positioning the parison in a cavity defined between two mold halves;
- (b) puncturing the parison with a blow needle having an outlet end so as to extend the needle into the interior of the parison;
- (c) passing a gas from the outlet end of the blow needle so as to inflate the parison;
- (d) providing a sleeve around said blow needle, said sleeve having at least one projection extending therefrom which surrounds said blow needle;
- (e) positioning said sleeve with respect to said parison so that said at least one projection extends into the cavity so as to contact the exterior surface of the parison, wherein step (b) is performed before said at least one projection contacts the parison and wherein said parison conforms to the shape of said at least one projection during inflation of the parison so as to form sealing contact between the parison and said at least one projection, thereby effectively preventing loss of gas pressure within said parison due to leakage around said blow needle;
- and
- (f) completing inflation of the parison so as to form the article.
4 more elements
Dependencies are inferred from the claim text.