"Bankers were at first reluctant to adopt a lock that barred friend as well as foe."
John Erroll and David Erroll, writers
It is thought that the first time-lock safe was patented by Scotsman Williams Rutherford in 1831. His work was part of a race between banks wanting to keep their vaults secure and robbers trying to break into them.
The Romans were the first to invent locks made out of metal, and these had special notches and grooves that made them more difficult to pick. In 1784 Joseph Bramah invented the first "unpickable" lock, although one locksmith did succeed, albeit after more than fifty-one hours—more time than robbers normally have at their disposal. However, during the 1800s the incidence of bank robberies was fast increasing.
The solution to the problem was the time-lock, a clockwork device that prevented the bolt of a lock from being opened until a defined moment in time. Even with the correct key (or combination in the case of a combination lock), a time-lock cannot be opened until a predetermined point in time has arrived. For example, banks locking their vaults over the weekend would be unable to open them again until Monday morning.
The design that formed the basis for modern time-locks was patented more than forty years later, in 1873, by James Sargent, an employee of Yale. This model was reliable, secure, and easy to use. After its introduction in banks, robbers were forced to come up with more elaborate ways of gaining entry, such as using explosives to blow open the doors.
