Trying to identify this swing-out brass key

I found this brass key that I'm trying to figure out what it's used for, and where it originated.

Any and all help would be greatly appreciated. Thank you!

 

It could be intended as a key that will only secure or unlock a lock. Turn it one way and the swing part allows the movement, turn the other way and the swing part blocks the motion with a ward in the center.

Although you show the part swung right out its movement in the lock would be much smaller.

I don't know why you'd want a key that only locked or unlocked, but this would be one way of doing it.

 

Welcome!

 

Maybe so Barney will quit locking himself in jail?

 

He's out at the moment, but I'll ask him when he gets back.

 

Hubby never saw one like it and says maybe for a clock or a mechanism with clockwork?