Helical blow molding preform and method of manufacturing

• US 7,157,040 B2
• Filed: 10/29/2005
• Issued: 01/02/2007
• Est. Priority Date: 11/01/2004
• Status: Expired due to Fees

• Current Assignee: William M. Yates III
• Original Assignee: William M. Yates III
• Inventors: Yates, William M. III
• Primary Examiner(s): McDowell; Suzanne E.
• Application Number:
  US11/163,765
• Publication Number:
  US 20060097432A1
• Time in Patent Office: 430 Days
• Field of Search: 264/532, 264/534, 264/535, 264/537
• US Class Current: 264/532
• CPC Class Codes: B29C 2949/0715 the preform having one end closed
• CPC Class Codes: B29C 2949/072 having variable wall thickness
• CPC Class Codes: B29C 2949/0722 at neck portion
• CPC Class Codes: B29C 2949/0723 at flange portion
• CPC Class Codes: B29C 2949/073 having variable diameter
• CPC Class Codes: B29C 2949/0731 at neck portion
• CPC Class Codes: B29C 2949/0732 at flange portion
• CPC Class Codes: B29C 2949/0733 at body portion
• CPC Class Codes: B29C 2949/074 having ribs or protrusions
• CPC Class Codes: B29C 2949/075 having at least one internal separating wall
• CPC Class Codes: B29C 2949/0751 at neck portion
• CPC Class Codes: B29C 2949/0752 at flange portion
• CPC Class Codes: B29C 2949/0753 at body portion
• CPC Class Codes: B29C 2949/0754 at bottom portion
• CPC Class Codes: B29C 2949/077 characterised by the neck
• CPC Class Codes: B29C 2949/0773 Threads
• CPC Class Codes: B29C 2949/0774 Interrupted threads
• CPC Class Codes: B29C 2949/22 at neck portion
• CPC Class Codes: B29C 2949/24 at flange portion
• CPC Class Codes: B29C 2949/26 at body portion
• CPC Class Codes: B29C 2949/28 : at bottom portion
• CPC Class Codes: B29C 45/44 : for undercut articles
• CPC Class Codes: B29C 49/06 : Injection blow-moulding
• CPC Class Codes: B29C 49/12 : Stretching rods
• CPC Class Codes: B29C 49/1206 : using at least two stretching rods for stretching different parts of the preform
• CPC Class Codes: B29K 2105/253 : Preform
• CPC Class Codes: B65D 1/04 : Multi-cavity bottles

Abstract

A multiple cavity bottle is manufactured by injection molding a preform having a helical septum and blow molding the preform to create a bottle having a helical septum separating the bottle into two cavities. The helical septum is molded with a twist sufficient to accommodate a contact point size for stretch rods used in blow molding. Blow molding is then accomplished by inserting at least two stretch rods from the top end of the preform to the contact points, heating the preform to a softening temperature, extending the stretch rods to stretch the preform and introducing gas pressure into the preform to stretch a blow molding portion into a final bottle shape within a mold.

Claims

1. A method for manufacturing a multiple cavity bottle comprising the steps of:

injection molding a preform having a helical septum;

blow molding the preform to create a bottle having a helical septum to separate the bottle into two cavities.

2. A method for manufacturing a bottle as defined in claim 1 wherein the step of injection molding further comprises the steps of:

predetermining a contact point size based on stretch rod diameter;

molding the helical septum with a twist from a first reference line proximate a top end of the preform to a second reference line proximate a bottom end of the preform, the sectors formed by the second reference line and a projection of the first reference line in a plane with the second reference line sufficient to accommodate the contact point size.

3. A method for manufacturing a bottle as defined in claim 2 wherein the step of blow molding comprises the steps of:

heating the preform to a softening temperature;

inserting a stretch rod from the top end of the preform to a contact point in the sectors;

extending the stretch rod to stretch the preform; and

introducing gas pressure into the preform to stretch a blow molding portion into a final bottle shape within a mold.

4. A method for manufacturing a bottle as defined in claim 1 wherein the step of injection molding further comprises the steps of:

providing a mold assembly incorporating a helical core mold received within a two sided cavity mold;

injecting plastic into the mold assembly;

allowing partial cooling of the molded plastic; and

removing the helical core mold by unscrewing it from the molded preform.

5. A method for manufacturing a bottle as defined in claim 1 wherein the step of injection molding further comprises the steps of:

providing a mold assembly incorporating a helical core mold received within a two sided cavity mold;

injecting plastic into the mold assembly;

allowing partial cooling of the molded plastic; and

unscrewing the preform from the core mold.

6. A method for manufacturing a bottle as defined in claim 4 further including the step of:

providing an indexing feature in the cavity mold to create a mating indexing feature in the preform.

7. A method for manufacturing a bottle as defined in claim 1 wherein the step of injection molding comprises:

injection molding a preform with a helical septum and having a length substantially equal to the final bottle dimension.

8. A method for manufacturing a bottle as defined in claim 7 further comprising the steps of:

providing a mold assembly comprised of a helical core mold received within a two sided cavity mold;

injecting plastic into the mold assembly;

allowing partial cooling of the molded plastic; and

removing the helical core mold by unscrewing it from the molded preform.

9. A method for manufacturing a bottle as defined in claim 7 further comprising the steps of:

providing a mold assembly comprised of a helical core mold received within a two sided cavity mold;

injecting plastic into the mold assembly;

allowing partial cooling of the molded plastic; and

unscrewing the preform from the core mold.

10. A method for manufacturing a bottle as defined in claim 9 further including the step of:

providing an indexing feature in the cavity mold to create a mating indexing feature in the preform.

11. A method for manufacturing a bottle as defined in claim 7 further comprising the steps of:

providing a mold assembly comprised of a helical core mold with an ejector sleeve, the core mold received within a two sided cavity mold;

injecting plastic into the mold assembly;

allowing partial cooling of the molded plastic removing the two sided cavity mold; and

ejecting the preform with the ejector sleeve, the preform rotating from the core mold.

12. A method for manufacturing a bottle as defined in claim 1 further comprising the steps of:

providing a mold assembly comprised of a helical core mold with an ejector sleeve, the core mold received within a two sided cavity mold;

injecting plastic into the mold assembly;

allowing partial cooling of the molded plastic removing the two sided cavity mold; and

ejecting the preform with the ejector sleeve, the preform rotating from the core mold.

13. A method for manufacturing a bottle as defined in claim 2 wherein the step of blow molding comprises the steps of:

heating the preform to a softening temperature;

inserting at least two stretch rods from the top end of the preform to the contact points in the sectors;

extending the stretch rods to stretch the preform; and

introducing gas pressure into the preform to stretch a blow molding portion into a final bottle shape within a mold.