How do stereotypical old-fashioned keyholes work?


In many games and cartoons, a lock with a keyhole on a door allows a person to look through it to see the room on the other side. How would a key unlock said lock, if it seems like the key would simply pass all the way through the door?

In: Technology

There is a hole that passes all the way through. The key has a large tab that sticks out from the stem [(pic)]( The tab goes in below the hole, and as you turn the key the tab interacts with the mechanism, unlocking the door. The mechanism can thus occupy the cylinder swept by the tab, all but a little bit of which is not in the keyway.