lLevers Mechanisation and Motion

BY BEN HARRISON

An introduction to motions !!!!There are four main types of motion. The motion is described by the direction it is travelling or moving. The motions include:1.Rotary – is when the object goes around (e.g. Wheels on a bike )2.Linear – is when the object moves in a straight line (e.g. A man walking in a straight line).3.Reciprocating – is when the object goes up and down in a straight line or side to side. ( e.g. A car being serviced)4.Oscillation - is when the object goes backwards and forward (e.g. A swing)

Changes in motionMotions can also be connected to make various other motions . Some examples are :a key an a

lock transfers from rotary motion to linear motion and also a windscreen wiper linkage

turns from rotary motion to oscillation.

An introduction to levers!A lever was probably one of the first tools used by humans. They allow you to lift far heavier objects

that you could manage by yourself. The lever system is made of three parts:

Effort – the effort you put into to move the lever.Load – the weight of the object that was moved.

Fulcrum – the point at which the lever turns. There are three classes of lever , each class depends on what is in the middle. A way of

remembering what is in the middle is :1 2 3 – F L E

The classes

Class 1 – is F or P because the pivot or the fulcrum is in the middle .

Class 2 – is L because the load is in the middle.

Class 3 – is E because the effort is in the middle.

PulleysA pulley is a wheel with a groove on the outside

of it. Its most common use is to pull heavy objects up and down. The distance you pull the

rope down is the distance the load will move up.

GearsGear wheels are like pulleys they are used for transferring rotary motion. However a gear

system can take more load than a pulley can, but if there is too much weight the teeth break o0ff

and the system is ruined.

CamsCams are used in mechanisms to change from rotary

to reciprocating motion.They come in three basic shapes pear shaped , ratchet

shaped and eccentric shaped. The follower must always be toughing the cam by gravity or a return

spring fitted to them.

The follower

The cam