What is a Lever?
A lever is a simple machine consisting of a beam positioned on a fixed point (the fulcrum) and used to transmit force, as in raising or moving a weight at one end by pushing down on the other.
The Boom of a Crane A boom (arm) or mounts its movable platform. Pulleys and levers help to raise the boom to lift or drop objects. Generally a hook suspends from the boom.
Where are the Levers used in and throughout the Crane?
Most cranes utilize the lever to lift exceptionally large loads. Almost all mounted cranes and many balanced cranes maximize lifting capacity with the lever. The lever itself is a stable bar that rests on a point, or fulcrum. Levers are used in the balance-style crane. The crane's beam is balanced at the fulcrum, allowing it to lift heavier objects with a smaller amount of force.
The lever manipulates torque. Torque measures the distance over which a force is applied. Torque equals force times distance.
Origin of Levers Levers were first described about 260 BC by the ancient Greek mathematician Archimedes (287-212 BC).It is one of the sever simple machines identified by Renaissance Scientists. The earliest writings which depicted levers date back to about 3 B.C. The origin of the lever dates to prehistoric times when people discovered that placing a rock under the end of a stick or beam allowed the lifting of heavy objects with little effort.
Parts of the crane that act like levers
Balance cranes and all mounted cranes optimize lifting capacity through the lever. These cranes have a mechanical arm that acts as a lever. Although the arm is usually accompanied by a complex system of pulleys, ropes, and chains. The Jib of a crane uses levers. The jib of a tower crane comprises the long metal arm, which sits on top of the mast. This is the part of the crane which carries the load.
Classes of Levers
First class levers describe levers where the fulcrum is situated between the effort force on one side and the load on the other, such as a seesaw or crowbar. When the load force sits between the fulcrum and the effort force, scientists deem this a second class lever. A wheelbarrow is a type of second class lever. And finally, third class levers denote when the effort force is applied
