The unpickable lock that sat in a London shop window for 67 years
From 1790, Joseph Bramah kept a lock in his Piccadilly shop window with a standing offer of 200 pounds to anyone who could pick it. Nobody managed it for over six decades. Then, at the Great Exhibition of 1851, an American locksmith named Alfred Charles Hobbs sat down with it and, after some 51 hours spread across 16 days, opened it.
Locks are far older than Bramah. One of the earliest known turned up in the ruins of Nineveh, the Assyrian capital, and the idea grew into the Egyptian wooden pin lock. Inside the door fixture, pins dropped part-way into holes drilled in a wooden bolt and held it fast; the right key lifted them clear so the bolt could slide. Romans developed metal locks and keys guarded by internal obstructions called wards, and wealthy Romans wore the keys to their strongboxes as finger rings, which kept them handy and showed off that they owned something worth protecting.
The Industrial Revolution, with its precision engineering, made locks much cleverer. Robert Barron patented a lever tumbler lock in 1778 in which each lever had to be raised to exactly the right height, so lifting it too far failed just as surely as lifting it too little. After a burglary at Portsmouth Dockyard, the British government ran a competition for a lock only its own key could open. Jeremiah Chubb answered in 1818 with a detector lock that jammed when tampered with and told the owner someone had tried. He won 100 pounds after a trained lock-picker spent three months failing to beat it.
Bramah took another route in 1784, using a cylindrical key whose precise notches pushed metal slides into perfect alignment. His design pushed the manufacturing precision of the age to its limit, which is why he felt confident offering a prize. The pin tumbler lock followed: an American physician, Abraham Stansbury, patented a double-acting version in England in 1805, and Linus Yale Sr. created the modern form in 1848, essentially a refined descendant of the Egyptian pin lock.
Most locks sold today are still variations on the designs of Bramah, Chubb and Yale, even as keycards, rolling radio codes in car keys and smartphone-controlled smart locks join them.
Source: Lock and key
