Heron of Alexandria (ca. 10–75 AD)already listed in his work ‘Mechanics’ five mechanisms that can "set a load in motion"; lever, windlass, pulley, wedge, and screw.


hefbomenA lever (crowbar, wrecking bar, pry bar, prise bar) is a mechanism by which a small force with a large movement is converted in a small move of a great burden. It usually has a seesaw shape, slide under the load a rod, push underneath a support or pivot (fulcrum), and lift the burden by pushing the other end of the rod.
If the force exerted on the power arm is smaller, that distance to the fulcrum should be (and vice versa) larger. The pulley works on the same principle.

There are three types of levers depending on the order of Load, Fulcrum and Power:

(LFP) the pivot point between load and power (scissors, pliers, saw, crowbar or spade)
(FLP) the load is between the fulcrum and the force (wheelbarrow, (garlic) press, bellows or nutcracker)
(FPL), the force is applied between the fulcrum and the load (tweezers, nail clippers, or our lower jaw)

The balance of power is shown in the following formulas: load arm x Load = power arm x Power, or even (power x arm) left = (power x arm) right.

A simple and remarkable application makes it possible to move very heavy massive volumes by using the load itself as lever on its own, with a changing fulcrum. The Moai (giant, sculpted monoliths on Easter Island) would be moved this way. (See also <End civilization / Deforesting>). The movie shows that people eventually were even right when they said that the statues walked to their place.
http://www.youtube.com/watch?v=YpNuh-J5IgE&feature=player_embedded

Pulley, block and tackle, hoist

TakelsA pulley is a disc with a groove on the periphery where the rope is running. The disc is mounted with an axle in a bracket or block cheeks with a mounting hook or eye. The pulley can thus change direction of the pull power and the rope.
A fixed pulley is attached to a fixed point, for example a crane, ceiling...
A loose pulley is attached to the load, and thus moves with the load.

In a block multiple disks can sit together on a single axis, or be divided on multiple axes. This is called a hoist or block and tackle. A tackle is a combination of a block (with 1 or 2 disks), and a one disk hook block.
If you use two pulleys and the rope changes 2x direction, you can lift a load with only half of the power. With three changes of direction only 1/3rd etc.

A winch usually consist of a drum with a transmission and a drive in which the rope or the cable is in one or more layers wound. We know them mostly from boats (and SUVs) .There is a difference, especially in (fall) protection between lifting- and pull winches.