The securimax can opener works really well. :)

Simply:

The thick rim of a can is sliced by the securimax can opener, leaving a very very weak connection to the can, this just comes off easily else you then use a gripper on the side of the opener to lift it.

You are left with a part rim around the top of the can and a lid with part rim still on it held by the opener.

Complexly:

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=6058613.WKU.&OS=PN/6058613&RS=PN/6058613

Securimax can opener is made in China.