Earliest one-hand opener?

[shortgoth]

I know the owner and moderators don't like people posting links to auctions so I won't post a link. But on eBay.co.uk there's a J Rodgers & Co. twin-bladed knife with ivory handle scales that was made some time between 1902 and 1952 that has attached studs to open the blades instead of the usual nail nicks.

Does anyone know of an earlier example? I must admit I thought one-hand opening folders were a more modern thing.

 

[SIFU1A]

dont have proof, but bet they would be older than that, 1800's at least imho.......seems like i read that in blade/some kinda knife mag

sifu