Lever tumbler lock

A minimum number of levers may be specified to provide an anticipated level of security (see § Five-lever locks).

"Double acting" lever tumbler locks were invented in 1778 by Robert Barron of England.

This type of lock is still used today, on doors in Europe, Africa, South America and some other parts of the world.

Each lever needs to be lifted to a specific height by the key in order for the locking bolt to move.

A lever will have pockets (or gates) through which the bolt stump (or post or fence) moves during unlocking.

Animation of a lever tumbler lock mechanism
A five-lever lock which is designed to be mortised into a door . The faceplate has been removed to see the inner workings.
A type of lock pick used to pick lever tumbler locks