1. Structures and Mechanisms

2. Structure or Mechanism?
Can you identify a Structure within this bicycle?
Can you name a mechanisms on this bicycle?
Frame = Structure
Chain and Sprocket = One example of a mechanism

3. Bridge Supporting Roadway
Introduction
Structures can be seen all around us in our everyday lives.
High Rise Building
Vehicle Frame
Bridge Supporting Roadway
Residential Dwelling

4. Introduction Tractor Drill Car Luas Exercise Bicycle
Machinery is a central part of life today. How many can you identify?
Tractor
Drill
Car
Luas
Exercise Bicycle

5. Introduction All these machines have working parts called –Mechanisms
Rack and Pinion
Pulley Wheels
Cam and Follower

6. Introduction 2. Wheelbarrow Look at the following items. 1. Bicycle
3. Wrench
4. Entrance
Can you identify and name the mechanisms and/or structure in each of these items?

7. Mechanisms, Motion and Force
A system of moving parts that performs some function.
Collins Dictionary
Motion
The process of continual change in the position of an object “movement”
Collins Dictionary

8. Motion and Force Force “Strength or Power”
What input is needed for a drill to work?
Exertion or the use of exertion against a person or thing that resists.
Collins Dictionary
Input: The lever of the drill is pulled down
Output: The chuck of the drill moves down

9. Motion There are four main types of motion. Linear motion – Train
Pendulum
There are four main types of motion.
Linear motion – Train
Oscillating Motion – Pendulum of a clock
Reciprocating Motion – Hacksaw
Rotary Motion - Shaft
Train
Shaft

10. Motion – movement in a straight line Linear motion
A train on its tracks moves in a linear motion
Can you give other examples of linear motion?

11. - backwards and forwards movement
Motion
Reciprocating Motion
- backwards and forwards movement
The engine pistons and valves above move up and down (reciprocate) continuously.
Can you suggest other examples?

12. Motion Rotary Motion The wheels of a bike move in a rotary fashion.
Motion in a circular direction, which can also be called circular motion .
Forward and backward movement in an arc
The wheels of a bike move in a rotary fashion.
Oscillating Motion
The pendulum of a clock or a child on a swing
are examples of oscillating motion.

13. Force There are five main types of force: Compression Tension Shear
Bending
Torsion
Shear forces
Columns in
Compression
A rope in Tension
Torsion forces
Pipe Bending

14. Force Can crushed by compression
Compressive and Tensile Forces
Can crushed by compression
This is where a load presses or squashes objects together
Spring in Tension, this is where a load pulls an object apart.

15. Force Torsion and Shearing forces This is where the load
causes an object to twist
This is where loads push at right angles to the surface of the object. E.g. scissors
Torsion force

16. Force Bending and Static Forces
This is where the load causes an object to Bend
A piece of metal
Dynamic Load – a car which is not fixed to any one specific point, e.g. a car travelling along a road
Bending a piece of metal
Static Load – a load which is fixed at one point, e.g. a building