Tin Can Opener's History-www.china-tin-boxes.com
The first tin cans were so thick they had to be hammered open.
As cans became thinner, it became possible to invent dedicated can openers. In 1858, Ezra Warner of Waterbury, Connecticut patented the first tin can opener. The U.S. military used it during the Civil War. In 1866, J. Osterhoudt patented the tin can with a key opener that you can find on sardine tin cans.