US 6,767,487 B2Granted

Plastic expulsion process

AssigneeCinpres Gas Injection Ltd.

InventorTerrence C. Pearson

Life of this patent

Estimating the term…

Abstract

A system and process for gas assisted plastic injection molding. The plastic material is injected into the mold cavity and the molding pressure is held for a period of time. Thereafter, gas is injected into the plastic material and the pressure is again held for a period of time. Thereafter, valve members are opened allowing plastic to be expelled into one or more secondary cavities, or to be expelled back into the machine barrel.

Claims16

Dependent claims

A process for injection molding a hollow plastic article comprising the steps of:

(a) injecting a quantity of plastic material into a mold cavity to substantially fill the mold cavity;
(b) applying a packing pressure to the plastic in the mold cavity;
(c) injecting pressurized gas into the plastic material in the mold cavity in order to combine the application of packing pressure to the plastic;
(d) holding the pressure of the gas and plastic in the mold cavity for a predetermined amount of time;
and
(e) allowing a portion of the plastic material in the mold to be expelled into at least one secondary cavity coupled to the mold cavity by opening a valve in a runner connecting the mold cavity to the secondary cavity.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/902,354Filed 10 Jul 2001
Published: US 2003/0011110 A116 Jan 2003
Granted: 27 Jul 2004
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

B29C 45/762
Measuring, controlling or regulating: the sequence of operations of an injection cycle
B29C 45/1711
The fluid being introduced into the interior of the injected material which is still in a molten state, e.g. for producing hollow articles: and…
B29C 2045/1712
And removing excess material from the mould cavity by the introduced fluid, e.g. to an overflow cavity: plastic material flowing back into the…
B29C 2045/1713
And removing excess material from the mould cavity by the introduced fluid, e.g. to an overflow cavity: using several overflow cavities

Family

US 2003/0011110 A1Pre-grant publication · published 16 Jan 2003
US 6,767,487 B2This patent

From the US filing history. Foreign family members aren’t listed.

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Abstract

Facts

Application

09/902,354Filed 10 Jul 2001

Published

US 2003/0011110 A116 Jan 2003

Granted

27 Jul 2004

Term ends

Not estimatedThe source records don’t support an estimate.

Classification7 codes

B29C 45/762
Measuring, controlling or regulating: the sequence of operations of an injection cycle
B29C 45/1711
The fluid being introduced into the interior of the injected material which is still in a molten state, e.g. for producing hollow articles: and…
B29C 2045/1712
And removing excess material from the mould cavity by the introduced fluid, e.g. to an overflow cavity: plastic material flowing back into the…
B29C 2045/1713
And removing excess material from the mould cavity by the introduced fluid, e.g. to an overflow cavity: using several overflow cavities