A lever whoever two hands form a right direction or nearly a right angle having its fulcrum within apex of the perspective It is used in bell pulls plus in changing the way of bell wires at angles of spaces etc and also in equipment
- A lever whoever two arms form a right direction, or almost a right angle, having its fulcrum in the apex regarding the position. It really is utilized in bell brings plus in switching the way of bell wires at perspectives of areas, etc., and in addition in equipment.
A lever whose two hands form the right position, or nearly the right angle, featuring its fulcrum in the apex associated with direction. It's utilized in bell pulls plus in altering the path of bell wires at perspectives of areas, etc., and also in machinery.
The most successful of the first class, or pick machines, that of William Firth of Sheffield, consists essentially of a horizontal pick with two cutting arms placed one slightly in advance of the other, which is swung backwards and forwards by a pair of bell crank levers actuated by a horizontal cylinder engine mounted on a railway truck.