Living hinge

1. A system ( 20 ; 302 ) comprising the unitarily molded single-piece combination of:

a first portion ( 24 ; 324 );

a living hinge ( 22 ; 322 ); and

a second portion ( 26 ; 326 ) coupled by the living hinge to the first portion and shiftable between a first condition and a second condition via rotation about the living hinge,

wherein the living hinge comprises:

an upper face ( 88 ) and a lower face ( 90 );

a first end ( 80 ) at the first portion;

a second end ( 82 ) at the second portion;

a proximal region wherein the upper face is lengthwise concave and the lower face is lengthwise convex; and

a central portion ( 96 ), wherein in the as-molded condition a proximal-to-distal median of the hinge is generally upwardly convex and downwardly concave along the central portion and the upper face along the central portion is doubly convex and the lower face along the central portion is doubly concave.

2. The system of claim 1 wherein:

the first portion is a mounting base having an aperture ( 30 );

the second portion is a cap;

the first condition is a closed condition; and

the second condition is an open condition.

3. The system of claim 2 wherein:

spring bias of the living hinge will maintain the hinge in the open condition.

4. The system of claim 2 wherein:

the base is internally threaded ( 50 );

the cap, in the closed condition, surrounds and covers an upper rim portion of the base and has a detented engagement therewith.

5. The system of claim 2 wherein:

the second condition is a relaxed condition;

the combination is molded of polypropylene.

6. The system of claim 1 wherein:

the thickness of the hinge decreases laterally from a location ( 98 ).

7. The system of claim 6 wherein:

the thickness of the hinge decreases proximally and distally from the location ( 98 ).

8. A system ( 20 ; 302 ) comprising the unitarily molded single-piece combination of:

a first portion ( 24 ; 324 );

a living hinge ( 22 ; 322 ); and

a second portion ( 26 ; 326 ) coupled by the living hinge to the first portion and shiftable between a first condition and a second condition via rotation about the living hinge,

wherein the living hinge comprises:

an upper face ( 88 ) and a lower face ( 90 );

a first end ( 80 ) at the first portion;

a second end ( 82 ) at the second portion;

a proximal region wherein the upper face is lengthwise concave and the lower face is lengthwise convex; and

a central portion ( 96 ), wherein in the as-molded condition a proximal-to-distal median of the hinge is generally upwardly convex and downwardly concave along the central portion, wherein:

the location ( 98 ) is within the central portion; and

in transverse cross-section at a center of the hinge, the dimension between the lower face near the edges and the upper face near the center minus a thickness T 1 at the center is at least 10% of that thickness.

9. The system of claim 1 wherein:

the thickness of the hinge decreases proximally and distally from a location ( 98 ).

10. A system ( 20 ; 302 ) comprising the unitarily molded single-piece combination of:

a first portion ( 24 ; 324 );

a living hinge ( 22 ; 322 ); and

a second portion ( 26 ; 326 ) coupled by the living hinge to the first portion and shiftable between a first condition and a second condition via rotation about the living hinge,

wherein the living hinge comprises:

an upper face ( 88 ) and a lower face ( 90 );

a first end ( 80 ) at the first portion;

a second end ( 82 ) at the second portion;

a proximal region wherein the upper face is lengthwise concave and the lower face is lengthwise convex; and

a central portion ( 96 ), wherein in the as-molded condition a proximal-to-distal median of the hinge is generally upwardly convex and downwardly concave along the central portion, wherein:

the location is within the central portion; and

in transverse cross-section near the center, centers of said transverse cross-section at edges of the hinge are downwardly offset from a center of such cross-section at the center of the hinge.

11. The system of claim 1 wherein:

in the as-molded condition, the second portion is spaced upward from the first portion by a vertical offset (H 1 ) of at least 50% of a horizontal separation (S 1 ) between the first portion and the second portion.

12. The system of claim 1 wherein:

the first portion is a first mounting feature ( 324 ); and

the second portion is a second mounting feature ( 326 ).

13. The system of claim 1 wherein:

the first portion is a first mounting tab ( 324 ); and

the second portion is a second mounting tab ( 326 ).

14. A container ( 300 ) comprising at least one system of claim 13 as a hinge ( 302 ) and further comprising:

a container body ( 310 ); and

a closure assembly ( 312 ) comprising:

a mounting base ( 314 ) mounted to the container body;

said hinge ( 302 ) having its first mounting tab ( 324 ) received in a pocket ( 330 ) of the mounting base; and

a lid having a pocket ( 332 ) receiving the second mounting tab ( 326 ).

15. A system ( 20 ; 302 ) comprising the unitarily molded single-piece combination of:

a first portion ( 24 ; 324 );

a living hinge ( 22 ; 322 ); and

a second portion ( 26 ; 326 ) coupled by the living hinge to the first portion and shiftable between a first condition and second condition via rotation about the living hinge, wherein the living hinge comprises:

a first ( 80 ) end at the first portion; and

a second end ( 82 ) at the second portion, wherein, in the as-molded condition:

the second portion is spaced upward from the first portion by a vertical offset (H 1 ) of at least 50% of a horizontal separation (S 1 ) between the first portion and the second portion; and

the living hinge thins away from a central portion both laterally and proximally-to-distally, with a lateral thinning being at least 30% from a center of the hinge to lateral edges of the hinge.

16. The system of claim 15 wherein:

in the as-molded condition, the first end and second end are generally horizontal.

17. The system of claim 15 wherein:

in the as-molded condition, a proximal-to-distal median of the hinge is generally upwardly convex along a central portion.

18. A method for manufacturing the system of claim 15 comprising injection molding in the as-molded condition.

19. A system ( 20 ; 302 ) comprising the unitarily molded single-piece combination of:

a first portion ( 24 ; 324 );

a living hinge ( 22 ; 322 ); and

a second portion ( 26 ; 326 ) coupled by the living hinge to the first portion and shiftable between a closed condition and an open condition via rotation about the living hinge,

wherein the living hinge comprises:

an upper face ( 88 ) and a lower face ( 90 );

a first end ( 80 ) at the first portion;

a second end ( 82 ) at the second portion;

a proximal region wherein the upper face is lengthwise concave and the lower face is lengthwise convex; and

a central portion ( 96 ), wherein in the open condition a proximal-to-distal median of the hinge is generally upwardly convex and downwardly concave along the central portion and a transverse median of the hinge is generally upwardly convex and downwardly concave along the central.

20. A system ( 20 ; 302 ) comprising the unitarily molded single-piece combination of:

a first portion ( 24 ; 324 );

a living hinge ( 22 ; 322 ); and

a second portion ( 26 ; 326 ) coupled by the living hinge to the first portion and shiftable between a closed condition and an open condition via rotation about the living hinge,

wherein the living hinge comprises:

a first ( 80 ) end at the first portion; and

a second end ( 82 ) at the second portion, wherein, in the open condition:

the second portion is spaced upward from the first portion by a vertical offset (H 1 ) of at least 50% of a horizontal separation (S 1 ) between the first portion and the second portion; and

the living hinge thins away from a central portion both laterally and proximally-to-distally.

21. The system of claim 1 wherein the living hinge further comprises a distal region and wherein a lengthwise convexity of the upper face decreases from the central portion to the distal region and a lengthwise concavity of the lower face decreases from the central portion to the distal region.