Oldest Auto

[Berkley]

Originally Posted by David

it seems that in Europe they may have been in production as early as 1840.

I found one reference which suggests that by that time they were already known on both sides of the Atlantic:

William Beaver
This cutler appeared in a list in a Sheffield directory (1839) as a maker of lock and fly-open knives. The latter were automatic (or switch-blade) knives that were probably intended for the American market.

-Tweedale's Directory of Sheffield Cutlery Manufacturers 1740-2010