UNIT D: MECHANICAL SYSTEMS

Mr. Ilko

Where are Mechanical Systems Taking Us?

There have been remarkable improvements to our ways of life primarily due to Mechanical Systems

Some of the ways it has improved our lives are; Vehicle engines Medicine Resource gathering

These are but a few of the contributions that this Unit will explore

The Canadarm & Robonaut

One of the greatest contributions Canada has made to the International Space Station was made possible by mechanical systems

The Canadarm is a combination of several simple machines to create one complex one

Robo-naut is the first robot astronaut that combines many different simple machines to create a human-like robot

Simple Machines

The first machines were very simple devices, but each helped perform a task that made our lives even easier

The first machines were all very different in design, but all had one common thing They required humans as their source for

energy

Listing Some Historic Tasks

Meeting the Same Need in Different Ways

We use machines to perform tasks for us, we even use different machines to perform the same task,

For example, in order to get water you just turn on your tap. You use a variety of systems to perform that.

In the past it wasn’t so easy…

Cont…

People commonly used a water wheel or SAKIA to gather their water. This was a device that had buckets

attached to a rotating wheel that turned when animals rotated another connected wheel

The Past Still Alive

The ARCHIMEDES SCREW was created by Archimedes to more efficiently lift water from its source for people to drink and use

Leonardo Da Vinci used two of these screws to raise water up to a storage tank

Farmers use a modern day version of the Archimedes screw in their machines to move grain into trucks for transport

Simple Machines

There are 6 main simple machines that you must learn in this unit, and they are; Lever, Incline plane Wedge Screw Pulley Wheel and Axel

Each have their own advantages and disadvantages

Lever

Is a rigid bar or plank that can rotate around a pivot or fulcrum

Levers are used to reduce the force needed to carry out tasks like pulling nails or opening bottles

It can move larger loads than you could without using it

Three Types of Levers

First Class Lever – Have the fulcrum between the load and the point where the effort is being exerted

Second Class Lever – has the load between effort and the fulcrum

Third Class Lever – has the effort between the load and the fulcrum

First Class

Second Class

Third Class

Incline Plane

Commonly known as a ramp

Makes lifting a heavy load easier since the force is being exerted over a longer area rather than straight up

The steeper the incline the more force that is required to move the load

Ex. Loading ramps & wheel chair access ramps

Wedge

Similar in shape to an incline plane, but used to be forced into an object rather than lift one

By applying pressure to the wide end of the wedge, you exert the force on the narrow end to split an object apart

Can only be used to split objects

Ex. Knives and Axes

Screw

A cylinder with spiral grooves on the outside

Helps to increase the force your use, you can use very little force to drive a screw into an object

Or can rotate it to create linear motion (motion in straight lines)

Screws, Archimedes screw

Pulley

Consists of wire, rope or cable moving on a grooved wheel

Can be made up of one or many wheels, and can be fixed or movable

Are commonly linked together to move and lift objects you normally could not lift

Ex. Cranes and elevators

Wheel and Axel

Combination of two different wheels of different diameters that turn together

A longer motion on the wheel create a shorter but more powerful motion on the axel larger = wheel, Shorter = Axel

You must turn a greater distance to apply a force

Ex. Steering wheel and column in a car & a door knob