Lever

One of the basic tools that date from prehistoric times. Simply a beam (lever) is used to move a load with a fulcrum (pivot) and an applied force. The position of the three determines the mechanical advantage.

First Class Lever

With this type of lever the fulcrum is situated between the load and the applied force.

There are many examples of the first class lever including: scissors, crowbar, tack lifter, balance and pliers.

Example: Pliers

Second Class Lever

With this type of lever the load is situated between the fulcrum and the applied force.

Examples of second class levers are: nut-crackers, wheel barrow.

Example: Wheel barrow

Third Class Lever

With this type of lever the force is applied between the load and the fulcrum.

Examples of the third class lever are: tweezers, wool shears.

Historical Notes

  1. 260 BC The lever is first described by Archimedes. "Give me a place to stand, and I will move the Earth.", Archimedes

See also: Archimedes, Fulcrum, Pliers, Pulley, Windlass.

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Subjects: Mechanical Engineering Physics