Robert Barron was an English locksmith notable for his invention of the double–acting tumbler lock in 1778
Joseph Bramah is best known for the invention of the hydraulic press and the Bramah lock. The Bramah lock was patented in 1784 and was considered unpickable for more than 65 years until A.C. Hobbs picked it, taking over 50 hours.
Jeremiah Chubb invented the first detector lock in 1818. He invented the lock as the result of a Government competition to create an unpickable lock and it remained unpicked until 1851. A Chubb detector lock was the most advanced and secure tumbler lock. When someone tries to pick the lock or to open it using the wrong key, the lock is designed to jam in a locked state until either a special regulator key or the original key is used.
In 1820, Jeremiah Chubb and his brother Charles Chubb made some modification to their original lock design. The new version of the lock didn’t needed a regulator key to reset the lock, once it has been tried to open without it’s key. The number of lever tumblers was also increased to 6 (original lock had four). This modified version of lock was called combined Bramah–Chubb lock
James Sargent described the first successful key-changeable combination lock in 1857, the prototype for those used in contemporary bank vaults. The combination lock became popular with safe manufacturers and the United States Treasury Department.
Linus Yale Sr. & Linus Yale Jr.
Linus Yale, Sr. invented a pin tumbler lock in 1848. Linus Yale, Jr. improved his father’s lock in 1861, using a smaller, flat key with serrated edges that is the basis of modern pin-tumbler locks. Yale developed the modern combination lock in 1862.