Cap with additive chamber and associated packaging unit

1. A cap adapted to be attached to a container, said cap comprising:

a main body having a collapsible button defining an open-ended chamber;

a frangible membrane comprising metal foil operably engaged with the main body so as to cover the open-ended chamber; and

a piercing member comprising a spike, blade, punch, or combination thereof, extending from an inner surface of the collapsible button, the piercing member being configured to advance toward and interact with the frangible membrane when the collapsible button is collapsed, so as to pierce the frangible membrane;

wherein the collapsible button comprises a collapsible helical wall with helical creases that converge helically when the button is depressed and having an end sealed by a cover wall having an inner surface and an exterior surface, the helical wall and the cover wall cooperating to form the open-ended chamber, the frangible membrane being disposed opposite the inner surface of the cover wall; and

wherein the piercing member comprises a plurality of piercing elements and at least one of the plurality of piercing elements is a first piercing element of a first length joined to the inner surface of the cover wall at a first location for piercing the membrane and at least one of the other of the plurality of piercing elements is a second piercing element of a second length shorter than the first length and being joined to the inner surface of the cover wall at a second location remote from the first location for separating a portion of the pierced membrane and folding said portion into the container to provide an opening through which material is capable of flowing.

2. The cap of claim 1 wherein the main body comprises screw threads so as to be capable of attaching to a container having complementary screw threads.

3. The cap of claim 1 wherein the metal foil comprises aluminum.

4. The cap of claim 1 further comprising an overcap attached to the main body and configured to cover the collapsible button.

5. The cap of claim 1 wherein the cover wall has one of a substantially planar profile and a substantially convex profile.

6. The cap of claim 1 wherein the main body comprises at least one retaining clip configured to interact with and retain the collapsible button in a collapsed position.

7. The cap of claim 1 further comprising a bore seal including the frangible membrane, the bore seal being operably engaged with the main body and configured to position the frangible membrane to cover the open-ended chamber.

8. A packaging unit comprising a cap according to claim 1 and a container having a reservoir therein, wherein the cap is securely attached to an open end of the container to seal the reservoir and wherein the frangible membrane of the cap separates the chamber from the reservoir.

9. The cap of claim 1 wherein the helical wall tapers inwardly while extending toward the cover wall such that the collapsible button has a conical, recessed tapered helical form.

10. A cap adapted to be attached to a container, said cap comprising:

a main body having a collapsible button defining an open-ended chamber;

a frangible membrane operably engaged with the main body so as to cover the open-ended chamber; and

a piercing member extending from an inner surface of the collapsible button, the piercing member being configured to advance toward and interact with the frangible membrane when the collapsible button is collapsed, so as to pierce the frangible membrane;

wherein the collapsible button comprises a collapsible helical wall with helical creases that converge helically when the button is depressed and having an end sealed by a cover wall having an inner surface and an exterior surface, the helical wall and the cover wall cooperating to form the open-ended chamber, the frangible membrane being disposed opposite the inner surface of the cover wall;

a bore seal including the frangible membrane, the bore seal being operably engaged with the main body and configured to position the frangible membrane to cover the open-ended chamber; and

wherein the bore seal comprises a ring seal and a snap bead, the ring seal and the snap bead cooperating with the frangible membrane to seal the open-ended chamber.

11. A cap adapted to be attached to a container, said cap comprising:

a main body having a collapsible button defining an open-ended chamber;

a frangible membrane operably engaged with the main body so as to cover the open-ended chamber; and

a piercing member extending from an inner surface of the collapsible button, the piercing member being configured to advance toward and interact with the frangible membrane when the collapsible button is collapsed, so as to pierce the frangible membrane;

wherein the collapsible button comprises a collapsible side wall and an upper end sealed by a cover wall having an inner surface and an exterior surface, the side wall and the cover wall cooperating to form the open-ended chamber, the frangible membrane being disposed opposite the inner surface of the cover wall;

wherein the main body comprises at least one retaining clip configured to retain the collapsible button in a collapsed position; and

wherein the at least one retaining clip comprises L-shaped clips mounted on a lateral surface of the main body adjacent to the collapsible button, each of the L-shaped clips comprising a first leg protruding upwardly from the lateral surface of the main body and a second leg connected to the first leg and protruding inwardly from the first leg toward the collapsible button so as to overlap a periphery of the cover wall of the collapsible button such that the cover wall and L-shaped clip interact to retain the collapsible button in the collapsed position.

12. The cap of claim 11 wherein the L-shaped clips are spaced apart along the periphery of the cover wall of the collapsible button.

13. The cap of claim 12 wherein the L-shaped clips comprise a pair of L-shaped clips located in opposing locations along the periphery of the cover wall of the collapsible button.