Key 1 has wedge-shaped notches 3 of various sizes. Cylindrical tumbler 4 has holes with pins 2. The lengths of pins 2 are such that when their lower ends enter the corresponding notches of the key (as shown) their upper ends are flush with the surface of the tumbler, holding pins 5 in holes of the fixed part of the lock and keeping them out of the holes in tumbler 4. Under this condition, tumbler 4 can be turned by key 1, opening the lock. If a key is inserted with notches of different size, some of pins 2 will extend into the holes of the fixed part of the lock and some of pins 5 will extend into the holes in tumbler 4. In this case it will be impossible to turn the tumbler and open the lock with this key. Pins 2 and 5 are held in contact with each other by springs 6.
$2200$WL,FD$