Pulley Mechanism

Transmission of PowerPulley Mechanism

ByManoj Tiwari
DFT/NIFT-G’Nagar

Learning ObjectivesTo understand the Pulley
Mechanism
To develop the understanding of Mechanical
Advantage using pulleys.
To explore the applications of
Pulleys for mechanical power transmission Class room Teachings by Manoj Tiwari

2

Pulley…
The pulley a variation of the axle and wheel; the wheel is grooved to guide a rope, chain or cable along the circumference of the wheel, which moves freely around the axle.

Class room Teachings by Manoj Tiwari

3

Pulley…
At its most simple use, the pulley works to change the direction of force applied in a system. More complex uses of pulleys are frequently used to gain mechanical advantage in a system.

Class room Teachings by Manoj Tiwari

4

Pulley Systems…
Fixed (Class 1) Pulley
Moveable (Class II) Pulley
Combination (Class III) Pulley

Class room Teachings by Manoj Tiwari

5

Fixed Pulley…
Often used to alter the direction of force in a system
Weight of force is equal to the weight of the object being moved. Advantage is gained by moving the operator away from the load

Class room Teachings by Manoj Tiwari

6

Fixed Pulley…
•A fixed pulley does not increase your force and therefore gives you no advantage. •It helps a person lift things by changing the direction of force. It allows a person to pull down in order to lift a load up.
Class room Teachings by Manoj Tiwari

7

Fixed Pulley…

Class room Teachings by Manoj Tiwari

8

Movable pulley (Floating Pulley)…
Used to gain mechanical advantage to lift weight (W) by multiplying the forces
Weight of force (F) required to move the object is equal to the number of ropes (N) supporting the load (W). F = W/N

Class room Teachings by Manoj Tiwari

9

Movable Pulley…
It is called a movable pulley because it moves with the load.
The pulley is suspended by a rope with one portion of the rope
(called a