The 1st picture: This is a brake mechanism which consists of many levers with 2 fixed pivot points joined together. This mechanism utilizes a reverse motion linkage. The output moves in the same direction as the input, hence a push-pull linkage is used. When the handled is pushed backwards towards the wheel in a linear motion, the pivots which is not in the centre of the levers will enable the brake to move backwards, and lock the wheels.
The 2nd picture: The hand crank sharpener utilizes a set of planetary gears with blades attached to the ends of the rotary gears. The central gear is connected to the hand crank. When the effort applied causes the crank to move in a rotary motion, the planetary gears turn as a result which causes the rotary gears to turn and the blade to sharpen the pencil.
The 3rd picture: This is a simple mechanism that utilizes a first class lever where the fulcrum is in between the load and the effort. When the effort applied pushes the handles towards each other, the pivot in the centre of the pair of scissors will enable the blades to close and cut the load. In contrast, when the effort applied pulls the handles away from each other, the pivot of the pair of scissors will enable the blades to release. For this mechanism, the output moves in the same direction as the input.
The 4th picture: This is a roller blind which makes use of a pulley to operate. When one side of the chain of the pulley is pulled downwards in a linear motion, the pulley will allow the roller blind to move downwards. Whereas, when the other side of the chain of the pulley is pulled downwards, the pulley will allow the roller blind to move upwards. The pulley enables the user to use less effort to move the load as the effort applied moves towards gravity.
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