The pin tumbler lock
is a lock mechanism that uses pins of varying lengths to prevent the lock from opening without the correct key.
- Without a key in the lock, the driver pins (blue) are pushed downwards, preventing the plug (yellow) from rotating.
- When an incorrect key is inserted into the lock, the key pins (red) and driver pins do not align with the shear line; therefore, it does not allow the plug to rotate.
- When the correct key is inserted, the gaps between the key pins and driver pins align with the edge of the plug.
- With the gaps between the pins aligned with the shear line, the plug can rotate freely.