Category: Power Transmission Devices

Gears can be classified according to position of shafts as follows.

There are mainly two forms of gear teeth: Forms of Teeth There are mainly two forms of gear teeth: Cycloidal Profile Teeth A cycloid is the locus of points on the circumference of a circle that rolls without slipping on a fixed straight line. An epicycloid is the locus of points on the circumference of…

The law of gearing gives the condition for the tooth profiles for constant angular velocity for two mating gears, which can be explained as: “If angular velocities of two mating gears remain constant, the common normal at the point of the two teeth should always pass through a fixed point P which divides the line…

All the important gear terminologies are shown in Figure 15.14. Pitch Point: The point of contact between pitch circles of two gears is known as pitch point. Pitch Circle: The circle passing through point of contacts of two gears is known as pitch circle. Pitch Diameter, D: Diameter of pitch circle is known as pitch diameter. Circular Pitch, Pc: It…

Gears are compact power transmission device that controls the speed, torque, and direction of rotation of driven shaft. Gears may be classified into five main categories: spur, helical, bevel, hypoid, and worm. Shaft orientation, efficiency, and speed determine the application of gear drive. Gears are toothed disc which transmit power from one shaft to other…

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…