Today in 2014, US Patent 8671802 B2 was issued, an invention of Chikamitsu Takagi, for his “Bottle Cap Opener.” Here’s the Abstract:

A movable outer cylindrical member and a movable inner cylindrical member are arranged vertically movably in a lower half of a cylindrical main body. By placing the movable inner cylindrical member on a bottle mouth and pushing down the cylindrical main body, a lower end of a hooking member is engaged with a lower end of the crown cap to pry the crown cap away. At the same time, the movable outer cylindrical member is moved up and a piston inside a cylinder arranged in an upper half of the cylindrical main body is moved up with the movable outer cylindrical member, so that the air in the cylinder is compressed, and a cover member is brought out in by the compressed air.