1. Mechanisms, Levers & Linkages
GCSE Graphic Products

2. The principles of simple mechanisms
Learning Objectives
By the end of this lesson you will have developed a knowledge and understanding of:
the principles of simple mechanisms and identify the relevant components and features
levers and linkages.

3. The principles of simple mechanisms
A mechanism creates movement within a product.
There will be occasions when the graphic designer needs to include a mechanism in a product, whether it be a board game or a moving sign.

4. Movement Movement Description Diagram Linear Moving in one direct
Reciprocal / reciprocating
Moving back and forth
Rotary
Turning in a circular motion
Oscillating
Swinging side to side in alternate directions

5. The lever The lever is the simplest of mechanism.
A lever is a device that pivots around a point called the fulcrum.
When a force is applied to one side, the other side moves in the opposite direction.
By positioning the fulcrum the outputting force can be magnified, or diminished.
The speed and distance of the movement can also be magnified, or diminished.
AQA GCSE Design and Technology: graphic products

6. Types of lever Levers can be categorised as one of three types:
Type of lever
Description
Diagram
Product
Class 1
The force/effort and the load are on opposite sides of the fulcrum
Seesaw
Class 2
The load is in between the effort and the fulcrum
Wheelbarrow
Class 3
The effort is in between the load and the fulcrum
Tweezers

7. Linkages A linkage can act as a lever.
In most cases it transfers one mechanical motion to another.
A linkage is often used to connect other mechanical devices such as cams to levers or to cranks – or vice versa.
A simple linkage will see a lever attached to a lever.

8. Types of linkages Linkage fixed pivots
Linkage brings about change in direction and movement

9. Types of linkages Linkage with several moveable parts
Components that can be used for pivots

10. Key terms
Lever – a rigid bar that can rotate around a fixed pivot called a fulcrum.
Linkage – a mechanism involving two or more levers.
Mechanism – creates movement.
Pivot – a point of rotation.

11. Task
Make the different types of linkage