Lever fulcrum to where the output force is applied (point "B"), then the lever amplifies the input force. On the other hand, if the distance "a" from the fulcrum to the input force is less than the distance "b" from the fulcrum to the output force, then the lever reduces the input force. The use of velocity in the static analysis of a lever is an application of the principle of virtual work. A lever is modeled as a rigid bar connected to a ground frame by a hinged joint called a fulcrum. The lever is operated by applying an input
Lever escapement escapement was invented by British clockmaker Thomas Mudge around 1755, and improved by Abraham-Louis Breguet (1787), Peter Litherland (1791), Edward Massey (1800), and its modern ("table roller") form was developed by George Savage in the early 1800s. Since about 1900 virtually every mechanical watch, alarm clock and other portable timepiece has used the lever escapement. The advantages of the lever are, first, that it is a "detached" escapement, it allows the balance wheel to swing completely free of the escapement during most of its oscillation, except when giving it a short impulse, improving timekeeping accuracy. Second, due to "locking" and