Plastic blow molded container having stable freestanding base

• US 6,019,236 A
• Filed: 09/10/1997
• Issued: 02/01/2000
• Est. Priority Date: 09/10/1997
• Status: Expired due to Term

• Current Assignee: Plastipak Packaging Incorporated (Plastipak Holdings Incorporated)
• Original Assignee: Plastipak Packaging Incorporated (Plastipak Holdings Incorporated)
• Inventors: Slat, William A.
• Primary Examiner(s): Weaver, Sue A.
• Application Number:
  US08/926,852
• Time in Patent Office: 874 Days
• Field of Search: 215/375, 215/377, 220/606, 220/608, 220/609
• US Class Current: 215/375
• CPC Class Codes: B65D 1/0284 having a discontinuous contact surface, e.g. discrete feet

Abstract

A plastic blow molded container (10) is disclosed as including a freestanding base structure (20) that is constructed with a plurality of alternating hollow legs (22) and curved ribs (34), and a hub (41) from which the legs and ribs extend radially with a construction that provides good stability against tipping as well as the capability of withstanding internal pressure. The hollow leg (22) has lower flat feet (24) with curved outer extremities that extend circumferentially for 45 to 65 percent of the extent about a central axis A of the container to provide good stability against tipping. Best results are achieved when the lower flat feet have curved outer extremities that extend circumferentially for 50 to 60 percent, and most preferably about 55 percent of the extent about the central axis A to provide the good stability against tipping.

Claims

1. In a plastic blow molded container having a central axis A and including a cylindrical body portion that extends vertically about the central axis A with a diameter D, an upper end closure unitary with the upper extremity of the cylindrical body portion and including a dispensing spout, and a freestanding base structure unitary with the cylindrical body portion to close the lower extremity thereof, said freestanding base structure comprising:

a plurality of downwardly projecting hollow legs spaced circumferentially from each other with respect to the body portion;

each leg having a lower flat foot coplanar with the feet of the other legs to cooperate therewith in supporting the container in an upright position;

the lower flat feet having outer curved extremities that extend circumferentially for 45 to 65 percent of the extent about the central axis to provide good stability against tipping;

each leg also having an outer wall that extends from the outer extremity of the flat foot thereof to the cylindrical body portion;

the flat foot and the outer wall of each leg having a curved junction;

each leg also having an inner connecting portion that extends upwardly and inwardly from the inner extremity of the flat foot thereof; and

each leg also having a pair of side walls that cooperate with the flat foot, the outer wall and the inner connecting portion to close the leg;

a plurality of curved ribs spaced circumferentially from each other between the downwardly projecting legs and connecting the adjacent side walls of the legs;

each rib having an outer upper end that extends upwardly for connection to the cylindrical body portion of the container;

each rib also having an inner lower end located between the inner connecting portions of the legs and extending downwardly and inwardly toward the central axis A of the container; and

each rib also having a curved intermediate portion that extends between the outer upper and inner lower ends thereof with an outwardly convex shape; and

a generally round hub that is located along the central axis A with the legs and curved ribs extending radially therefrom;

said hub having a diameter D_h in the range of about 0.15 to 0.25 of the diameter D of the cylindrical body portion; and

the hub having connections to the upwardly extending inner connecting portions of the legs and the hub also having connections to the downwardly extending inner lower ends of the curved ribs.

2. A plastic blow molded container as in claim 1 whose lower flat feet have outer curved extremities that extend circumferentially for 50 to 60 percent of the extent about the central axis A to provide the good stability against tipping.

3. A plastic blow molded container as in claim 1 whose lower flat feet have outer curved extremities that extend circumferentially for 55 percent of the extent about the central axis A to provide the good stability against tipping.

4. A plastic blow molded container as in claim 1 wherein the hub of the base structure has an upwardly extending shape including a periphery connected to the upwardly extending inner connecting portions of the legs and to the downwardly extending inner lower ends of the curved ribs.

5. A plastic blow molded container as in claim 1 wherein the hub has a generally flat shape that extends horizontally and has a periphery connected to the upwardly extending inner connecting portions of the legs and to the downwardly extending inner lower ends of the curved ribs.

6. A plastic blow molded container as in claim 1 wherein the hub has a downwardly extending shape including a periphery connected to the upwardly extending inner connecting portions of the legs and to the downwardly extending inner lower ends of the curved ribs.

7. A plastic blow molded container as in claim 1 wherein the outer upper end of each rib has a circumferential width W_u, and the inner lower end of each rib has a circumferential width W_l, that is larger than the circumferential width W_u of the outer upper end of the rib.

8. A plastic blow molded container as in claim 7 wherein the curved intermediate portion of each rib has a circumferential width that tapers from the inner lower end thereof to the outer upper end thereof with an included angle in the range of about 1°

to 8°

.

9. A plastic blow molded container as in claim 8 wherein the included angle defined by the curved intermediate portion of each rib is about 2°

.

10. A plastic blow molded container as in claim 1 wherein the outer curved extremities of the lower flat feet have an outer diameter D_f, the periphery of the hub being spaced above the plane of the flat feet of the legs by a height H_p, and the ratio of the diameter D_f over the height H_p being in the range of about 25 to 90.

11. A plastic blow molded container as in claim 1 wherein the outer curved extremities of the lower flat feet have an outer diameter D_f, the curved intermediate portion of each rib having a circumferential width that tapers from the inner lower end thereof to the outer upper end thereof with an included angle of about 1°

to 8°

, the periphery of the hub being spaced above the plane of the flat feet of the legs by a height H_p, and the ratio of the diameter D_f over the height H_p being in the range of about 25 to 90.

12. A plastic blow molded container as in claim 1 wherein the outer curved extremities of the lower flat feet have a diameter D_f that is at least 0.75 of the diameter D of the cylindrical body portion.

13. A plastic blow molded container as in claim 1 wherein the lower flat foot of each leg has a truncated wedge shape.

14. A plastic blow molded container as in claim 1 wherein the outer wall of each leg has a curved shape including an upper end that is tangent with the adjacent portion of the lower extremity of the cylindrical body portion.

15. A plastic blow molded container as in claim 14 wherein the outer wall of each leg has a radius of curvature R_w greater than 0.75 of the diameter D of the cylindrical body portion.

16. A plastic blow molded container as in claim 1 wherein each rib has a radius of curvature R_r greater than about 0.6 of the diameter D of the cylindrical body portion and with a center of curvature on the opposite side of the central axis A from the rib.

17. A plastic blow molded container as in claim 14 wherein the outer wall of each leg has a radius of curvature R_w greater than 0.75 of the diameter D of the cylindrical body portion, and each rib having a radius of curvature R_r greater than about 0.6 of the diameter D of the cylindrical body portion and with a center of curvature on the opposite side of the central axis A from the rib.

18. A plastic blow molded container as in claim 1 which includes five legs and five ribs.

19. In a plastic blow molded container having a central axis A and including a cylindrical body portion that extends vertically about the central axis A with a diameter D, an upper end closure unitary with the upper extremity of the cylindrical body portion and including a dispensing spout, and a freestanding base structure unitary with the cylindrical body portion to close the lower extremity thereof, said freestanding base structure comprising:

a plurality of downwardly projecting hollow legs spaced circumferentially from each other with respect to the body portion;

each leg having a lower flat foot coplanar with the feet of the other legs to cooperate therewith in supporting the container in an upright position;

the lower flat feet having outer curved extremities that have a diameter D_f and extend circumferentially for 50 to 60 percent of the extent about the central axis A to provide good stability against tipping;

each lower flat foot having a truncated wedge shape;

each leg also having an outer wall that extends from the outer extremity of the flat foot thereof to the cylindrical body portion;

the outer wall of each leg having a curved shape with a radius of curvature R_w greater than 0.75 of the diameter D of the cylindrical body portion and including an upper end that is tangent with the adjacent portion of the lower extremity of the cylindrical body portion;

the flat foot and the outer wall of each leg having a curved junction;

each leg also having a inner connecting portion that is inclined and extends upwardly and inwardly from the inner extremity of the flat foot thereof; and

each leg also having a pair of side walls that cooperate with the flat foot, the outer wall and the inner connecting portion to close the leg;

a plurality of curved ribs spaced circumferentially from each other between the downwardly projecting legs and connecting the adjacent side walls of the legs;

each rib having an outer upper end that has a circumferential width W_u and extends upwardly for connection to the cylindrical body portion of the container;

each rib also having an inner lower end located between the inner connecting portions of the legs;

the inner lower end of each rib having a circumferential width W_l that is larger than the circumferential width W_u of the outer upper end of the rib;

each rib also having a curved intermediate portion that extends between the outer upper and inner lower ends thereof with an outwardly convex shape;

the curved intermediate portion of each rib having a circumferential width that tapers from the inner lower end thereof to the outer upper end thereof with an included angle in the range of about 1°

to 8°

; and

each rib having a radius of curvature R_r greater than about 0.6 of the diameter D of the cylindrical body portion and with a center of curvature on the opposite side of the central axis A from the rib and extending downwardly and inwardly from toward the central axis A of the container; and

a generally round hub that is located along the central axis A with the legs and curved ribs extending radially therefrom;

said hub having a periphery with a diameter D_h in the range of about 0.15 to 0.25 of the diameter D of the cylindrical body portion;

the periphery of the hub also having connections to the upwardly extending inner connecting portions of the legs and to the downwardly extending inner lower ends of the curved ribs;

the periphery of the hub being spaced above the plane of the flat feet of the legs by a height H_p ; and

the ratio of the diameter D_f over the height H_p being in the range of about 25 to 90.

20. In a plastic blow molded container having a central axis A and including a cylindrical body portion that extends vertically about the central axis A with a diameter D and has a nominal wall thickness t, an upper end closure unitary with the upper extremity of the cylindrical body portion and including a dispensing spout, and a freestanding base structure unitary with the cylindrical body portion to close the lower extremity thereof, said freestanding base structure comprising:

a plurality of downwardly projecting hollow legs spaced circumferentially from each other with respect to the body portion;

each leg having a lower flat foot coplanar with the feet of the other legs to cooperate therewith in supporting the container in an upright position;

the lower flat feet having outer curved extremities that have a diameter D_f and extend circumferentially for about 55 percent of the extent about the central axis A to provide good stability against tipping;

each lower flat foot having a truncated wedge shape;

each leg also having an outer wall that extends from the outer extremity of the flat foot thereof to the cylindrical body portion;

the outer wall of each leg having a curved shape with a radius of curvature R_w and including an upper end that is tangent with the adjacent portion of the lower extremity of the cylindrical body portion;

the flat foot and the outer wall of each leg having an abruptly curved junction with a radius of curvature R_j less than 0.05 of the diameter D of the cylindrical body portion;

each leg also having a inner connecting portion that is inclined and extends upwardly and inwardly from the inner extremity of the flat foot thereof; and

each leg also having a pair of side walls that cooperate with the flat foot, the outer wall and the inner connecting portion to close the leg;

a plurality of curved ribs spaced circumferentially from each other between the downwardly projecting legs and connecting the adjacent side walls of the legs;

each rib having an outer upper end that has a circumferential width W_u and extends upwardly for connection to the cylindrical body portion of the container;

each rib also having an inner lower end located between the inner connecting portions of the legs and extending downwardly and inwardly toward the central axis A of the container;

the inner lower end of each rib having a circumferential width W_l that is larger than the circumferential width W_u of the outer upper end of the rib;

each rib also having a curved intermediate portion that extends between the outer upper and inner lower ends thereof with an outwardly convex shape;

the curved intermediate portion of each rib having a circumferential width that tapers from the inner lower end thereof to the outer upper end thereof with an included angle in the range of about 1°

to 8°

; and

each rib having a radius of curvature R_r greater than about 0.6 of the diameter D of the cylindrical body portion and with a center of curvature on the opposite side of the central axis A from the rib;

a generally round hub that is located along the central axis A with the legs and curved ribs extending radially therefrom;

said hub having a periphery with a diameter D_h in the range of about 0.15 to 0.25 of the diameter D of the cylindrical body portion;

the periphery of the hub also having connections to the upwardly extending inner connecting portions of the legs and to the downwardly extending inner lower ends of the curved ribs;

the periphery of the hub being spaced above the plane of the flat feet of the legs by a height H_p ; and

the ratio of the diameter D_f over the height H_p being in the range of about 25 to 90;

the inner extremities of the flat feet, the inner connecting portions of the legs, the inner lower ends of the curved ribs, and the hub each having a wall thickness t'"'"' that is at least 3 times the nominal wall thickness t of the cylindrical body portion.