Child resistant airtight lid

1. An airtight lid, comprising:

an outer cap comprising a first wall and a first skirt depending from the first wall, wherein the first wall includes a protrusion extending radially inwardly from the first skirt;

an inner cap comprising an annular recess defined by a base annular wall and outer and inner skirts extending from the base annular wall, a central recess defined by the inner skirt and a central wall attached at an end of the inner skirt opposite from the base annular wall, the central wall comprising a first plurality of arcuate slots disposed therethrough;

a gasket comprising a sheet of compressible material having a second plurality of arcuate slots disposed therethrough; and

a snap cap comprising a flat plate having a plurality of flexible snap fingers extending therefrom;

wherein a subassembly comprises the gasket secured between the inner cap and the snap cap by the plurality of flexible snap fingers disposed through the first and second pluralities of arcuate slots; and

wherein the protrusion extending radially inwardly from the first skirt snaps over a shoulder on the outer skirt to attach the outer cap over the inner cap.

2. The airtight lid of claim 1 , wherein the gasket further comprises a central circular aperture disposed therethrough and the snap cap further comprises a central protruding structure extending therefrom, wherein the central protruding structure is accommodated by the central circular aperture when the subassembly is assembled.

3. The airtight lid of claim 1 , wherein a plurality of radially oriented elongate protrusions is circumferentially distributed on an inner surface of the first wall and a surface of the annular wall facing away from the annular recess includes an arrangement of a plurality of ramped elongate radially oriented protrusions circumferentially distributed thereon.

4. The airtight lid of claim 3 , wherein the outer cap has a first height (H 1 ) measured between an inner side of the protrusion extending radially inwardly from the first skirt and outward most surfaces of the plurality of radially oriented elongate protrusions, wherein the first height (H 1 ) is greater than a second height (H 2 ) measured on the inner cap between the shoulder on the outer skirt and top most surfaces of the plurality of ramped elongate radially oriented protrusions.

5. The airtight lid of claim 4 , wherein the plurality of ramped elongate radially oriented protrusions is arranged so that the ramped portion of each protrusion faces in a clockwise sense when viewed from above, and wherein the side of each protrusion facing in a counter-clockwise sense when viewed from above is a right angle.

6. The airtight lid of claim 5 , wherein the outer cap and the inner cap have first and second engaging geometries, wherein in a first engaging geometry the outer cap is positioned with the protrusion extending radially inwardly from the first skirt close to the shoulder on the outer skirt so that the outer cap freely rotates relative to the inner cap without the plurality of radially oriented elongate protrusions interfering with the plurality of ramped elongate radially oriented protrusions, and wherein in a second engaging geometry the outer cap is positioned with the plurality of radially oriented elongate protrusions close to or touching the surface of the annular wall facing away from the annular recess.

7. The airtight lid of claim 1 , wherein an outer edge of the gasket when assembled in the subassembly between the snap cap and the inner cap extends radially beyond both of the snap cap and the inner cap.

8. The airtight lid of claim 1 , wherein the outer edge of the gasket has a configuration selected from the group of configurations consisting of being beveled to a sharp edge, being squared off, being rounded, or having a three-sided edge.

9. The airtight lid of claim 1 , wherein the inner cap further comprises a set of threads that extend radially inwardly from an inner surface of the outer skirt.

10. An airtight lid, comprising:

an outer cap comprising a first wall and a first skirt depending from the first wall, wherein the first wall includes a protrusion extending radially inwardly from the first skirt;

an inner cap comprising an annular recess defined by a base annular wall and outer and inner skirts extending from the base annular wall, a central recess defined by the inner skirt and a central wall attached at an end of the inner skirt opposite from the base annular wall, the central wall comprising a first plurality of arcuate slots disposed therethrough;

a gasket comprising a sheet of compressible material having a second plurality of arcuate slots disposed therethrough; and

a snap cap comprising a flat plate having a plurality of flexible snap fingers extending therefrom;

wherein a subassembly comprises the gasket secured between the inner cap and the snap cap by the plurality of flexible snap fingers disposed through the first and second pluralities of arcuate slots, wherein an outer edge of the gasket when assembled in the subassembly between the snap cap and the inner cap extends radially beyond both of the snap cap and the inner cap; and

wherein the protrusion extending radially inwardly from the first skirt snaps over a shoulder on the outer skirt to attach the outer cap over the inner cap.

11. The airtight lid of claim 10 , wherein the gasket further comprises a central circular aperture disposed therethrough and the snap cap further comprises a central protruding structure extending therefrom, wherein the central protruding structure is accommodated by the central circular aperture when the subassembly is assembled.

12. The airtight lid of claim 10 , wherein each of the first plurality of arcuate slots has a radially directed ramped outer radial edge so that each of the first plurality of arcuate slots is larger at a side of the central wall facing away from the central recess.

13. The airtight lid of claim 12 , wherein each of the plurality of snap fingers includes a radially outwardly facing shoulder portion disposed on a free end thereof, and each of the shoulder portions further includes a ramped end surface.

14. The airtight lid of claim 10 , wherein a plurality of radially oriented elongate protrusions is circumferentially distributed on an inner surface of the first wall and a surface of the annular wall facing away from the annular recess includes an arrangement of a plurality of ramped elongate radially oriented protrusions circumferentially distributed thereon.

15. The airtight lid of claim 14 , wherein the outer cap has a first height (H 1 ) measured between an inner side of the protrusion extending radially inwardly from the first skirt and outward most surfaces of the plurality of radially oriented elongate protrusions, wherein the first height (H 1 ) is greater than a second height (H 2 ) measured on the inner cap between the shoulder on the outer skirt and top most surfaces of the plurality of ramped elongate radially oriented protrusions.

16. The airtight lid of claim 15 , wherein the plurality of ramped elongate radially oriented protrusions is arranged so that the ramped portion of each protrusion faces in a clockwise sense when viewed from above, and wherein the side of each protrusion facing in a counter-clockwise sense when viewed from above is a right angle.

17. An airtight lid, comprising:

an outer cap comprising a first wall and a first skirt depending from the first wall, wherein the first wall includes a protrusion extending radially inwardly from the first skirt;

an inner cap comprising an annular recess defined by a base annular wall and outer and inner skirts extending from the base annular wall, a central recess defined by the inner skirt and a central wall attached at an end of the inner skirt opposite from the base annular wall, the central wall comprising a first plurality of arcuate slots disposed therethrough;

a gasket comprising a sheet of compressible material having a second plurality of arcuate slots disposed therethrough; and

a snap cap comprising a flat plate having a plurality of flexible snap fingers extending therefrom;

wherein a subassembly comprises the gasket secured between the inner cap and the snap cap by the plurality of flexible snap fingers disposed through the first and second pluralities of arcuate slots;

wherein the protrusion extending radially inwardly from the first skirt snaps over a shoulder on the outer skirt to attach the outer cap over the inner cap; and

wherein a plurality of radially oriented elongate protrusions is circumferentially distributed on an inner surface of the first wall and a surface of the annular wall facing away from the annular recess includes an arrangement of a plurality of ramped elongate radially oriented protrusions circumferentially distributed thereon.

18. The airtight lid of claim 17 , wherein the outer cap has a first height (H 1 ) measured between an inner side of the protrusion extending radially inwardly from the first skirt and outward most surfaces of the plurality of radially oriented elongate protrusions, wherein the first height (H 1 ) is greater than a second height (H 2 ) measured on the inner cap between the shoulder on the outer skirt and top most surfaces of the plurality of ramped elongate radially oriented protrusions.

19. The airtight lid of claim 18 , wherein the plurality of ramped elongate radially oriented protrusions is arranged so that the ramped portion of each protrusion faces in a clockwise sense when viewed from above, and wherein the side of each protrusion facing in a counter-clockwise sense when viewed from above is a right angle.

20. The airtight lid of claim 17 , wherein an outer edge of the gasket when assembled in the subassembly between the snap cap and the inner cap extends radially beyond both of the snap cap and the inner cap.