The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 12, 1992
Filed:
Mar. 22, 1990
Indra R Baxi, Troy, MI (US);
Nitrojection Corporation, Middlefield, OH (US);
Abstract
A process for producing an injection molded product includes introducing a stream of plastic material into a mold space at a first pressure. A quantity of gas is stored in a storage chamber at a second pressure which is at least as high as the first pressure. The gas is introduced into the molten stream of plastic material immediately after the molten material has passed the position at which the gas is introduced thereby forming a gas cavity in the molten material. The gas exerts pressure on the surrounding plastic material to urge the material toward the surfaces of the mold space. As the feeding of the plastic material into the mold space continues, the injection of the gas is also continued. The supply of molten material is terminated when the surfaces of the mold space are completely covered by the molten material. A pressure is held within the gas cavity as the plastic material cools. Subsequently, the pressure is released to bring the mold space to ambient pressure. Then the mold is opened to remove the hollow shaped article. An apparatus for producing an injection molded product is also disclosed.