Apparatus for molding plastic articles

• US 4,219,322 A
• Filed: 12/20/1978
• Issued: 08/26/1980
• Est. Priority Date: 12/20/1978
• Status: Expired due to Term

• Current Assignee: Owens-Illinois Pty Limited (O-I Glass, Inc.)
• Original Assignee: Owens-Illinois Incorporated (O-I Glass, Inc.)
• Inventors: Kontz, Robert F., Chang, Long F.
• Primary Examiner(s): Hoag, W. E.
• Application Number:
  US05/971,279
• Time in Patent Office: 615 Days
• Field of Search: 425/134, 425/357, 425/359, 425/576, 425/588, 425/577, 425/561, 425/542, 425/555, 425/425, 425/431, 425/434, 425/469, 425/582, 425/574, 425/589, 425/594, 425/360 , 425/359-361, 425/416, 425/419, 425/423, 425/468, 264/538, 264/328, 264/513
• US Class Current: 425/547
• CPC Class Codes: B29C 45/06 mounted on a turntable , i.e. on a rotating support having a rotating axis parallel to the mould opening, closing or clamping direction
• CPC Class Codes: B29C 45/57 Exerting after-pressure on the moulding material B29C45/174 takes precedence
• CPC Class Codes: B29C 45/77 of velocity or pressure of moulding material

Abstract

A apparatus are disclosed for molding plastic articles, wherein the method includes the steps of filling a mold cavity at a first station with heated flowable plastic material and then displacing the mold to a second station where the plastic material is cooled under pressure. The apparatus includes a rotatable support for displacing the mold between the first and second stations, a plastic supply means at the first station to fill the molds, and a displaceable rod at the second station for insertion into the mold to apply pressure to the plastic material during solidification cooling.

Claims

1. An apparatus for forming a plastic article, comprising:

a movable mold having an internal mold cavity and a sprue opening;

supply means at a first station for filling the internal mold cavity and sprue opening with heated, flowable plastic material;

low pressure filling means at the first station to fill the mold at a pressure of less than about 5000 psi;

displacement means for moving the mold immediately after filling from the first station to a second station where the sprue opening is in alignment with an axially reciprocal pressurizing member; and

fluid power means for (a) axially displacing the pressurizing member into the sprue opening to apply pressure to the plastic material within the internal mold cavity and (b) maintaining pressure greater than the mold filling pressure on the member while the plastic material within the internal mold cavity is thermally conditioned to a self-sustaining state to provide a hollow plastic article.

2. The apparatus as defined in claim 1, including a rotatable turret interconnected to both said displacement means and the mold, said turret being mounted for rotation about an axis and the mold being movable with the turret along an arcuate path between said first and second stations.

3. A mold assembly, comprising:

a support member mounted for rotation about an axis;

a plurality of molds mounted on the periphery of the support member in circumferentially spaced relationship, with each of the molds including a sprue opening and cooling means;

a first station adjacent the circumferential periphery of the support member and including low pressure filling means for successively filling the molds with plastics material polyethylene terephthalate in heated, flowable condition at a pressure of less than about 5000 psi;

means for transferring the molds immediately after filling to a second station;

the second station being adjacent the circumferential periphery of the support member and including an axially reciprocal rod and a fluid power means for advancing the rod into the mold sprues to apply pressure to the plastic material within the molds at a pressure greater than the filling pressure while said cooling means cools the plastic material to a self-sustaining condition to obtain an hollow plastic article.

4. The apparatus as defined in claim 3, wherein each of the molds includes a female mold and a vertical core pin cooperatively defining an essentially tubular vertical cavity;

and the sprues being at the top of each mold cavity.