but narrowed the field of view, hiding the levers from anybody attempting to pick the lock. The Chubb brothers also received a patent for the first burglar-resisting safe and began production in 1835.

The designs of Barron and Chubb were based on the use of movable levers, but Joseph Bramah, a prolific inventor, developed an alternative method in 1784. His lock used a cylindrical key with precise notches along the surface; these moved the metal slides that impeded the