Pressure base for plastic container
View Patent ↗A base for a container is provided. The base includes an annular bearing surface that defines a bearing plane. The base also includes a parting line that extends along the base and defines first and second portions on opposite sides of the parting line. The base further includes an inner portion that is spaced from the bearing plane and surrounded by the annular bearing surface. In such a base, the first portion is offset from the second portion.
1. A container base comprising:
an annular bearing surface defining a bearing plane;
a parting line extending along the base defining first and second portions on opposite sides of the parting line;
an inner portion spaced from the bearing plane and surrounded by the annular bearing surface,
first and second lugs extending outwardly from the inner portion towards the bearing plane without intersecting the bearing plane, the first lug defining a first end surface, and the second lug defining a second end surface,
wherein the first portion and the second portion are offset from one another to form a common offset wall extending through the inner portion and including the first end surface and the second end surface, wherein the common offset wall comprises a vertical surface extending along the parting line, the vertical surface being substantially perpendicular to the inner portion and having a substantially uniform height between the first end surface and the second end surface, said offset wall providing resistance to distortion upon an increase of internal pressure within the container.
2. The base according to claim 1 , wherein the annular bearing surface defines only three touch points for contact with a horizontal surface.
3. The base according to claim 1 , wherein the annular bearing surface includes
an inner curvature having an inner radius of curvature, the inner curvature merging the annular bearing surface with the inner portion of the base.
4. The base according to claim 3 , wherein the annular bearing surface defines only three touch points for contact with a horizontal surface.
5. The base according to claim 1 , wherein the first and second lugs are substantially half-crescent-shaped and each has a wide end that extends along the parting line, wherein the first end surface extends along the wide end of the first lug, and the second end surface extends along the wide end of the second lug.
6. The base according to claim 5 , wherein the annular bearing surface includes
an inner curvature having an inner radius of curvature, the inner curvature merging the annular bearing surface with the inner portion of the base.
7. The base according to claim 6 , wherein the first lug includes first and second surfaces, the first surface of the first lug being interposed between the inner curvature and the second surface of the first lug, and the second surface of the first lug merging with the first portion, and
the second lug includes first and second surfaces, the first surface of the second lug being interposed between the inner curvature and the second surface of the second lug, and the second surface of the second lug merging with the second portion.
8. The base according to claim 1 , wherein the parting line extends substantially through the center of the base.
9. A container base comprising:
an annular bearing portion having a width and defining a bearing surface and a bearing plane;
a parting line extending along the base defining first and second portions on opposite sides of the parting line,
an inner portion having a diameter and being spaced from the bearing plane and surrounded by the annular bearing surface,
first and second lugs extending outwardly from the inner portion towards the bearing plane without intersecting the bearing plane, the first lug defining a first end surface, and the second lug defining a second end surface,
wherein the first portion and the second portion are offset from one another to form a common offset wall extending through the inner portion and including the first end surface and the second end surface, wherein the common offset wall comprises a vertical surface extending along the parting line, the vertical surface being substantially perpendicular to the inner portion and having a substantially uniform height between the first end surface and the second end surface,
further wherein the diameter of the inner portion is between 20 and 40 times the width of the annular bearing portion, and the base is capable of withstanding an increase in internal pressure.
10. The container according to claim 9 , wherein the inner portion has a radius of curvature and is spaced from the bearing plane in a direction that is substantially perpendicular to the bearing plane at a height that is between 0.065 and 0.085 times the radius of curvature.
11. The container according to claim 10 , wherein the diameter of the inner portion is between 25 and 35 times the width of the annular bearing portion.
12. The container according to claim 11 , wherein the diameter of the inner portion is 30 times the width of the annular bearing portion.
13. The container according to claim 10 , wherein the height is between about 0.070 and 0.080 times the radius of curvature.
14. The container according to claim 13 , wherein the height is about 0.075 times the radius of curvature.
15. The base according to claim 9 , wherein the annular bearing surface defines only three touch points for contact with a horizontal surface.
16. The base according to claim 9 , wherein the first and second lugs are substantially half-crescent-shaped and each has a wide end that extends along the parting line, wherein the first end surface extends along the wide end of the first lug, and the second end surface extends along the wide end of the second lug.
17. The base according to claim 9 , wherein the internal pressure is about 8 pounds per square inch (psi).
18. A method of packaging a product, comprising the steps of:
providing a container having a base according to claim 1 ;
placing the product into the container; and
providing an air tight seal over a mouth of the container.
19. A method of packaging a product, comprising the steps of:
providing a container having a base according to claim 9 ;
placing the product into the container; and
providing an air tight seal over a mouth of the container.
20. A container base comprising:
an annular bearing surface defining a bearing plane;
a linear parting line extending along the base defining first and second portions on opposite sides of the parting line;
an inner portion spaced from the bearing plane and surrounded by the annular bearing surface,
first and second lugs extending outwardly from the inner portion towards the bearing plane without intersecting the bearing plane, the first lug defining a first end surface, and the second lug defining a second end surface,
wherein the first and the second portion are offset from one another to form a common offset wall extending through the inner portion and including the first end surface and the second end surface, wherein the common offset wall comprises a vertical surface extending along the parting line, the vertical surface being substantially perpendicular to the inner portion and having a substantially uniform height between the first end surface and the second end surface.
21. A blow-molded ptastic container base comprising:
an annular bearing surface defining a bearing plane;
a parting line formed along the junctions of mold halves during blow-molding for extending along the base and defining first and second portions on opposite sides of the parting line;
an inner portion spaced from the bearing plane and surrounded by the annular bearing surface,
first and second lugs extending outwardly from the inner portion towards the bearing plane without intersecting the bearing plane, the first lug defining a first end surface, and the second lug defining a second end sutface,
wherein the first portion and the second portion are offset from one another to form a common offset wall extending through the inner portion and including the first end surface and the second end surface, wherein the common offset wall comprises a vertical surface extending along the parting line, the vertical surface being substantially perpendicular to the inner portion and having a substantially uniform height between the first end surface and the second end surface.
22. A container base comprising:
an annular bearing surface defining a bearing plane;
a parting line extending along the base defining substantially flat first and second portions on opposite sides of the parting line;
an inner portion spaced from the bearing plane and surrounded by the annular bearing surface,
first and second lugs extending outwardly from the inner portion towards the bearing plane without intersecting the bearing plane, the first lug defining a first end surface, and the second lug defining a second end surface,
wherein the first portion and the second portion are offset from one another to form a common offset wall extending through at least the inner portion and including the first end surface and the second end sutface, wherein the common offset wall comprises a vertical surface extending along the parting line, the vertical surface being substantially perpendicular to the inner portion and having a substantially uniform height between the first end surface and the second end surface.