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 hange 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 ncrease 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 ulley because it moves with the load. The pulley is suspended by a rope with one portion of the rope (called a rope segment) on each side. Each rope segment supports half the load. Class room Teachings by Manoj Tiwari 10 Movable Pulley… The pulley is suspended and as a consequence the mechanical advantage is increased. The rope on the left and right of the pulley are both lifting the LOAD, they each lift half its weight hence the load is split into 2 parts. Class room Teachings by Manoj Tiwari 11 Combination Pulley… •The problem with movable pulleys is that a person has to pull up to lift a load. In order to make the job of lifting a load easier, a fixed pulley can be added to allow lifting a load by pulling down. •By combining a fixed pulley to a movable pulley, a person gets the advantages of both. The movable pulley doubles the person’s force, and at the same time the fixed pulley let the person pull down to lift the load up. Class room Teachings by Manoj Tiwari 12 Combination Pulley… Class room Teachings by Manoj Tiwari 13 Combination Pulley… Class room Teachings by Manoj Tiwari 14 Combination Pulley… Class room Teachings by Manoj Tiwari 15 Questions… Class room Teachings by Manoj Tiwari 16