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Lock and key

technology Maturity 11-13 Next article →

A lock is a fastening device used to secure objects or areas.

Solex 99 30 padlock with keys (DSCF2659)
Solex 99 30 padlock with keys (DSCF2659)

These devices can be mechanical or electronic. They work by requiring specific input to release a bolt or cylinder. This input might be a physical object like a key or keycard. It could also be secret information like a password or a fingerprint. Locks are essential for security and access control. They ensure that only authorized persons can enter a space.

A typical mechanical key consists of two main parts.

Key anatomy
Key anatomy

The first part is the bow, which is the part the user holds. Applying torque to the bow allows the user to turn the key. The second part is the bit or blade. The blade slides into the keyway of the lock. The shape of the blade determines if it will work. In a warded lock, the key must have notches that match internal obstructions called wards.

Wardedlock
Wardedlock

These wards block the key unless the notches allow it to pass through. This allows the key to rotate and open the mechanism.

Different mechanical systems use different methods to stop a bolt from moving. The pin tumbler lock is a very common type. It uses pins of varying lengths to prevent the lock from turning. As the key slides in, the bittings—which are the teeth on the blade—lift the pins. The pins must align perfectly at the shear line. This alignment allows the inner and outer cylinder to rotate freely.

Another type is the lever tumbler lock. This uses a set of levers to block the bolt. The key must lift these levers to specific heights to allow movement.

Locking technology has a very long history spanning over 6,000 years. One of the earliest examples was found in the ruins of Nineveh in ancient Assyria. The Egyptians developed wooden pin locks using a bolt and a key. When the key was inserted, it lifted pins out of drilled holes. This allowed the bolt to move. The Romans later improved these designs by inventing metal locks. They also used a system of wards for security. Wealthy Romans often wore their keys on rings to show their status.

Scorpion Lock, Bronze from Nalanda, Bihar, dating from 10th century A.D.
Scorpion Lock, Bronze from Nalanda, Bihar, dating from 10th century A.D.

During the Industrial Revolution, locks became much more complex. In 1778, Robert Barron invented the lever tumbler lock.

Chubb lock
Chubb lock

This was a double-acting lock that required precise lever heights. Jeremiah Chubb improved this in 1818 with the Chubb detector lock. This lock could indicate if someone had tried to pick it. A lock-picker once failed to break a Chubb lock after three months. In 1784, Joseph Bramah created a cylindrical key lock. He offered a £200 reward to anyone who could pick it.

It took Alfred Charles Hobbs 51 hours over 16 days to win the prize in 1851.

Modern security often relies on the work of the Yale family. Linus Yale Sr. received a patent for a pin tumbler lock in 1805. However, Linus Yale Jr. perfected the design in 1861. He created a smaller, flat key with serrated edges. This design is still used in many homes today. We also see many specialized locks like the wafer tumbler lock. These are often used in automobiles and cabinetry because they are inexpensive to produce. Other versions, like the disc tumbler lock, use rotating detainer discs instead.

Today, we are moving toward electronic and smart locking systems. These locks use electric currents and actuators to move the bolt.

A keycard lock works by matching a signature on a flat card. Remote keyless systems use radio transmitters to send codes. Smart locks use wireless protocols and cryptographic keys. These can often be controlled by a smartphone. Because they use digital codes, they cannot be picked with traditional mechanical tools.

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🖼️ Images & Media (12)
File:Solex 99 30 padlock with keys (DSCF2659).jpg
Solex 99 30 padlock with keys (DSCF2659).jpg
File:Scorpion Lock, Bronze from Nalanda, Bihar, dating from 10th century A.D..jpg
Scorpion Lock, Bronze from Nalanda,...
File:Lock MET cdi55-61-5.jpg
Lock MET cdi55-61-5.jpg
File:Dronkenmansslot.jpg
Dronkenmansslot.jpg
File:Tibetan Lock and key - Dhankhar Gompa, Spiti. 2004.jpg
Tibetan Lock and key - Dhankhar Gompa,...
File:Chinese lock.JPG
Chinese lock.JPG
File:Key anatomy.jpg
Key anatomy.jpg
File:Chubb lock.jpg
Chubb lock.jpg
File:Mendel I 072 v.jpg
Mendel I 072 v.jpg
Copia llave video.ogv
File:Wardedlock.jpg
Wardedlock.jpg
File:Palestine Nakba Day demo in Berlin.jpg
Palestine Nakba Day demo in Berlin.jpg
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