Today in 2011, US Patent 20110036840 A1 was issued, an invention of Tal Zakai, for his “Ring Pull Can Cap.” Here’s the Abstract:

The present innovation is a dual purpose “ring-pull/can cap”, which performs as both a sealing cap for metal beverage cans in addition to its traditional usage as a can opener. The design is a modification of the U.S. Pat. No. 3,967,752 “easy open wall”, which is the current opening mechanism on most consumer beverage cans, also known in the industry as an “easy open end”. The “ring-pull/can cap” is an improvement of the well known ring-pull design found on most metal cans today, but also allows consumers to close and seal off the can when not in use.

There are two popular opening methods that have been used for opening metal cans to date: The “full open” mechanism and the more recent “half open” mechanism, as described below. The present invention deals with the improvement of the popular “half open” method, which currently does not allow the beverage can to be resealed after opening.