Pin tumbler lock is a locking mechanism widely used in cylinder locks featuring a series of pin pairs that are housed within a cylinder core. When the correct key is inserted into the lock, it aligns these pins at the shear line, allowing the cylinder to turn and the lock to open. This design utilises driver pins, typically made of metal, and key pins, which are cut to specific lengths to match the key’s unique profile.
The invention of the pin tumbler lock dates back to ancient Egypt, but its modern form was perfected by Linus Yale, Jr. in the 19th century, making it a prevalent choice for security applications today. The security level of pin tumbler locks can be enhanced by incorporating spool, serrated, or mushroom pins that resist lock picking, a technique known as lock bumping.
These locks are commonly employed in residential and commercial settings due to their reliability and the relative ease of rekeying. Specialised versions are also used in high-security environments, equipped with features such as sidebars and hardened steel inserts to counteract drilling and other forms of physical attack.