Claims
- 1. A method of providing a thermoplastic parison at orientation temperature for blow molding comprising: heating said thermoplastic parison to orientation temperature; applying pressure inward to opposed sides of said parison from areas spaced apart axially a slight distance to thus close off said parison and extrude a plurality of flat flanges at right angles to a longitudinal axis of said parison; cooling said thus extruded flanges to a solid condition to provide a rigid support; and holding said parison by said flanges as said parison is transferred axially and laterally.
- 2. A method according to claim 1 wherein said parison is heated by passing same in an upright position through an air oven.
- 3. A method according to claim 2 wherein said parison is lowered into position into a thread-forming zone and held thereby as said parison is stretched longitudinally by applying axial force to the opposite end thereof, and thereafter said thus stretched parison is sealed and severed at an end opposite said end held in said thread-forming zone and internal fluid pressure is introduced to expand same out into conformity with the molding zone.
- 4. A method according to claim 1 wherein said flanges have a thickness of 10 to 50 per cent of the single wall thickness of said parison.
CROSS REFERENCE TO RELATED APPLICATION
This application is a divisional of copending application Ser. No. 375,126 filed June 29, 1973 now U.S. Pat. No. 3,870,446.
US Referenced Citations (6)
Divisions (1)
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Number |
Date |
Country |
Parent |
375126 |
Jun 1973 |
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