Christopher Polhem and the ingenious Polhem lock

The Polhem lock was an advanced padlock in its day, designed and manufactured by mechanical engineer and inventor Christopher Polhem (1661–1751). This lock, which became widespread in Sweden, was forged of iron, easy to handle, unpickable, and had no springs. In the 19th century it was made in several places in Sweden, and it is now a desirable collector’s item.