A pin tumbler lock is one of the most common types of locks used in door security, padlocks, and other applications. Its mechanism relies on a set of pins that must be aligned at a specific height for the lock to turn. Here’s how it works:
The lock consists of a cylinder where a specially cut key is inserted. Inside the cylinder, there are two sets of pins: driver pins and key pins. The key pins rest directly on the key when inserted, and each corresponds to a particular notch on the key.
When no key is inserted, the driver pins and key pins block the rotation of the cylinder by straddling the shear line (the interface between the inner cylinder and the outer housing). When the correct key is inserted, the notches on the key push the key pins up to the right height, causing the driver pins to align at the shear line. Once all the pins align perfectly at this line, the cylinder can rotate, unlocking the lock.
As the cylinder rotates, it moves a cam or latch mechanism, allowing the lock to open. If the wrong key is inserted, the pins won’t align at the shear line, preventing the cylinder from turning.
A disc detainer lock, also known as an Abloy lock, operates on a different principle compared to the pin tumbler lock. It is often considered more secure and is used in high-security applications. Here’s how it works:
The lock consists of a series of rotating discs rather than pins. Each disc has a small notch and is positioned inside the lock cylinder. The key used for a disc detainer lock has a series of cuts or angles, designed to rotate these discs to specific positions.
When the key is inserted, the specially shaped cuts on the key interface with the discs, causing each disc to rotate to a particular angle. Each disc has a slot, and these slots must all line up to allow the lock to open.
When the correct key is used, the notches (or "gates") in the discs align perfectly with a sidebar mechanism inside the lock. This sidebar fits into the aligned gates, allowing the cylinder to rotate.
When the cylinder turns, it engages the locking mechanism, allowing the lock to open. If the wrong key is used, the discs will not align correctly, and the sidebar won’t be able to retract, thus preventing the lock from turning.
