Preform for making plastic container
View Patent ↗A preform for making a lightweighted plastic container includes a finish portion having at least one external thread defined thereon that has a first sidewall thickness, a main body portion, an end cap, and a transition portion between the end cap and the main body portion. The end cap has a second side wall thickness that preferably is not less than said first side wall thickness of the finish portion. The main body portion is preferably unstepped, and the outer surface of the transition portion is preferably concave as viewed in longitudinal cross-section. In addition, the transition portion preferably extends for a longitudinal distance, and a ratio of the longitudinal distance to an outer radius of the end cap is preferably within a range of about 0.3 to about 0.9.
1. A preform for making a plastic container, comprising:
a longitudinal axis;
a sidewall having an inner surface and an outer surface, said sidewall defining:
a finish portion having at least one external thread defined thereon, said finish portion having a first sidewall thickness;
a main body portion;
an end cap, said end cap having a second side wall thickness, said second side wall thickness being not less than said first side wall thickness, an inner surface of the end cap being curved; and
a transition portion between said end cap and said main body portion, wherein the inner surface of said sidewall that defines said transition portion is continuous with a proximal portion of the inner surface of the end cap and has a radius taken from the longitudinal axis, wherein the radius remains substantially constant along the transition portion; and a thickness of the sidewall that defines the transition portion increases from a distal end of the transition portion that joins the end cap to a proximal end of the transition portion that joins the main body portion.
2. A preform for making a plastic container according to claim 1 , wherein said second sidewall thickness is greater than said first sidewall thickness.
3. A preform for making a plastic container according to claim 1 , wherein said second side wall thickness is substantially equal to said first side wall thickness.
4. A preform according to claim 1 , wherein a portion of said sidewall defining said main body portion has a substantially constant wall thickness.
5. A preform according to claim 1 , wherein said main body portion is unstepped.
6. A preform according to claim 5 , wherein a portion of said outer surface of said sidewall that defines said transition portion is concave as viewed in longitudinal cross-section.
7. A preform according to claim 1 , wherein an outer surface of said end cap is convexly curved at a substantially constant radius.
8. A preform according to claim 1 , wherein the inner surface of said end cap is concavely curved at a substantially constant radius.
9. A preform according to claim 1 , wherein said end cap has a substantially constant wall thickness.
10. A preform according to claim 9 , wherein a ratio of said substantially constant wall thickness of said end cap to an outer radius of said end cap is within a range of about 0.20 to about 0.30.
11. A preform according to claim 10 , wherein said ratio of said substantially constant wall thickness of said end cap to an outer radius of said end cap within a range of about 0.21 to about 0.25.
12. A preform according to claim 1 , wherein said transition portion extends for a longitudinal distance, and wherein a ratio of said longitudinal distance to an outer radius of said end cap is within a range of about 0.3 to about 0.9.
13. A preform according to claim 12 , wherein said ratio is within a range of about 0.40 to about 0.65.
14. A plastic container made using a preform according to claim 1 .
15. A preform for making a plastic container, comprising:
a longitudinal axis;
a sidewall having an inner surface and an outer surface, said sidewall defining:
a finish portion having at least one external thread defined thereon;
an unstepped main body portion;
an end cap having a curved inner surface; and
a transition portion between said end cap and said main body portion, and wherein a portion of said outer surface of said sidewall that defines said transition portion is continuous with a proximal portion of the inner surface of the end cap and concave as viewed in longitudinal cross-section; and wherein said inner surface of said sidewall that defines said transition portion has a radius taken from the longitudinal axis, wherein the radius remains substantially constant along the transition portion.
16. A preform according to claim 15 , wherein a portion of said sidewall defining said main body portion has a substantially constant wall thickness.
17. A preform according to claim 15 , wherein said end cap has a substantially constant wall thickness.
18. A preform according to claim 17 , wherein a ratio of said substantially constant wall thickness of said end cap to an outer radius of said end cap is within a range of about 0.20 to about 0.30.
19. A preform according to claim 18 , wherein said ratio of said substantially constant wall thickness of said end cap to an outer radius of said end cap within a range of about 0.21 to about 0.25.
20. A preform according to claim 15 , wherein said transition portion extends for a longitudinal distance, and wherein a ratio of said longitudinal distance to an outer radius of said end cap is within a range of about 0.3 to about 0.9.
21. A preform according to claim 20 , wherein said ratio is within a range of about 0.40 to about 0.65.
22. A plastic container made using a preform according to claim 15 .
23. A preform for making a plastic container, comprising:
a longitudinal axis;
a sidewall having an inner surface and an outer surface, said sidewall defining:
a finish portion having at least one external thread defined thereon;
a main body portion;
an end cap, said end cap having a curved inner surface and an outer radius;
a transition portion between said end cap and said main body portion, and wherein said transition portion extends for a longitudinal distance, and wherein a ratio of said longitudinal distance to said outer radius of said end cap is within a range of about 0.3 to about 0.9; and wherein said inner surface of said sidewall that defines said transition portion is continuous with a proximal portion of the curved inner surface of the end cap and has a radius taken from the longitudinal axis, wherein the radius remains substantially constant along the transition portion; and
wherein a thickness of the sidewall that defines the transition portion increases from a distal end of the transition portion that joins the end cap to a proximal end of the transition portion that joins the main body portion.
24. A preform according to claim 23 , wherein said ratio is within a range of about 0.40 to about 0.65.
25. A plastic container made using a preform according to claim 23 .
26. A preform according to claim 8 , wherein the inner surface of the end cap and the inner surface of the transition portion have substantially the same radius.