PULLEY

By Jonathan Lemmon and Brook Dreher

Definition of Pulley

a wheel with a grooved rim for carrying a line, that turns in a frame or block and serves to change the direction of or to transmit force, as when one end of the line is pulled to raise a weight at the other end

How does it work?

A pulley is also called a sheave or a drum and is a mechanism made up of a wheel on an axle or shaft that may have a groove between two flanges around its boundary.

A rope, cable, belt, or chain usually runs over the wheel and inside the groove, if present.

Pulleys are used to change the direction of an applied force, or realize a mechanical advantage in either a linear or rotational system of motion

It looks like this

Uses

The pulley is used to move heavy objects by splitting the weight being pulled. Like a crane, it lifts up objects easily by using hydraulics in the arm so it is able to pull objects

How do you calculate IMA for the pulley Efficiency=AMA/IMA x 100%

AMA=Fr /Fe

Other info on pulleys

The pulley you turn causes the other pulley to turn also, because they are connected by a belt. The driver and the follower turn in the same direction.

Reference

http://www.eng.iastate.edu/twt/Courses/Undergrad/packet/info/pulleys.htm

The book http://en.wikipedia.org/wiki/Pulley