Author: Haroon Khalil

Hosting Chain: This type of chain is used for lower speed. It consists of oval links as shown in Figure 15.9. Figure 15.9 Hosting Chain Conveyer Chain: Conveyer chain may be detachable/hook joint type/closed end pintle type as shown in Figure 15.10. The sprocket teeth are so shaped and spaced that the chain could run onto and off the sprockets smoothly…

Let R and r are the radii of the pitch circle of two sprockets having teeth T and t, respectively. L is length of the chain C is centre distance between sprockets = K · p  Example 15.6: For reduction of speed from 250 to 100 rpm, a chain drive is used. Calculate the number of teeth on the driven sprocket if number of teeth on driven sprocket…

To overcome the problem of slip in belt drive or rope drive, chain drive is used. A schematic diagram of chain drive is shown in Figure 15.8. The velocity ratio in chain drive remains constant. But, chain drive is heavier than the belt drive and there is gradual stretching in its strength. Time to time some of…

Rope drive is very similar to belt drive. It is classified as: Figure 15.7 A Schematic View of Rope Fibre ropes are made of manila or cotton. Wire ropes are made of steel wires. A number of wires make a strand and strands make a rope as shown in Figure 15.7. Each strand is twisted with other strands.…

When velocity of the belt is more than 10 m/s, the centrifugal force becomes predominant. Analyse the various components of forces as shown in Figure 15.6. Let ρ is the density of belt materials     Tc is centrifugal tension on the belt element in tight and slack side     r is radius of the pulley     t is thickness of the belt     b is width…

Example 15.3: Two pulleys of diameters 500 and 200 mm are mounted on two parallel shafts 2 m apart. These shafts are connected by a cross belt. Find the angle of contact of belt and pulley. If larger pulley rotates at 250 rpm and maximum permissible tension in the belt is 1 kN, find the power…

Let   T1 is tension in tight side of the belt     T2 is tension in slack side of the belt     θ is angle of lap of belt over the pulley     μ is coefficient of friction between the belt and pulley Figure 15.5 Tensions in Belt Consider a short length of belt subtending an angle δθ at the centre of the pulley as shown…

Cross-belt drive is used to provide reverse direction of rotation to driven shaft as the direction of rotation of driving shaft. Similar to open-belt drive, let A and B be the pulley centres and CD and EF be the common tangents to the two pulleys as shown in Figure 15.4. Figure 15.4 Crossed-belt Drive In Figure 15.4, belt length, L = 2 (Arc GC + CD + Arc DH) Example 15.2: Two shafts drive are…

Open-belt drive is used to provide same direction of rotation to driven shaft as the direction of rotation of driving shaft. Let L is length of belt for open drive       r is radius of smaller pulley       R is radius of larger pulley       C is centre distance between pulleys       β is angle subtended by each common tangent on centre of pulley (CD)…

When belt passes from slack to tight side, a certain portion of belt extends and again contracts when belt passes through tight to slack side. Due to fluctuation in length of the belt, there is relative motion between belt and pulley surface. This relative motion is known as creep. Considering the creep, velocity ratio can…