made by Naeem akhtar about belt and pulleys

1. Belts And Pulleys

2. INTRODUCTION
A belt is a loop of flexible material used to mechanically link two or more rotating shafts, most
often parallel.
 Belts may be used as a source of motion, to transmit power efficiently, or to track relative
movement.
Belts are looped over pulleys and may have a twist between the pulleys, and the shafts need not
be parallel.

3. Belt Material
According to the Material Used Belts are classified into
 Leather Belts
 Cotton or Fabric Belts
 Rubber Belts
 Balata belts
(Similar to rubber belt except that balata gum is used in place of rubber)

4. Belt Drive and power transmition______
Amount of power transmitted by belt
depend on
 The velocity of the belt
 The Tension of the belt
 The arc of contact between the belt and smaller pulley
 The condition under which the belt is used

5. ABSTRACT
We are trying to understand the working of belt drives, their different components, the forces
involved and how are they transferred, to create a device of our own, innovating the current belt
drive system and developing our own system based on concepts of belt drive.

6. Why Used ?
 Transfer power (torque) from one location to another.
From driver: motor, peddles, engine, windmill, turbine to driven: conveyor belt, back wheels, generator
rock crusher, dryer.
 Used to span large distances or need flexible x-mission elements. Gear drives have a higher
torque capability but not flexible or cheap.
 Often used as torque increaser (speed reducer)

7. Belt Types_________________________

8. Type of Belt Drive
Type of
belt
drive
Flat
belt
VEE
Belts
Timing
Belt
Round
Belt

9. FLAT BELT DRIVE
They comprise of a simple flexible belt running between
the pulleys.
This type of belts are limited to transmission of less energy
because of their tendency to slip.
They might also have problems due to wrong alignment of belts.
Picture Source : Google Images

10. ROUND BELT DRIVE
They are just like ropes stretched between two pulleys.
They are very strong and are used in factories to transmit huge amount of power.
They are used to transfer power across large distances
Picture Source : Google Images

11. V-BELTS DRIVE_______________________
They have a trapezoidal “V” shape and track in a mating groove in the pulley.
The “V” shape of the belt solves the slipping and alignment problems.
They provide the best combination of Traction, Speed and Movement.
They need narrow but deeper grooves on the pulley for their functioning.
They can be used for transmission of large amount of power due to their strength.

12. TIMING BELT DRIVE__________________
These belts have tooth to have better grip on the pulley.
They runs on a matching toothed pulley. They have no slippage.
They can be used to transfer high amount of energy.
Due to their non-slipping mechanism they are used in Engines of vehicles and in turbochargers.
They are also used to transfer motion and timing purposes.
Picture Source : Google Images

13. ARRANGEMENT OF BELTDRIVE
1
•Open Belt Drive
2
•Closed Belt Drive

14. Open Belt Drive_____________________
In this type of arrangement the belt is put up on both the pulleys straightly without any twist or
turns.
This makes the driven pulley rotate in the same direction as that of the driver pulley.
This method is good for delivering more power as the belts rupture very less when compared
to other methods of arrangement.
Picture Source : Google Images

15. Closed Belt Drive__________________
In this type of arrangement the belt is given a turn as it runs between the pulleys.
The driver pulley and the driven pulley rotates in the opposite direction while in this type of
arrangement.
It cannot be used for delivering much power as the belt rubs against itself and gets ruptured
very fast in the process.

16. Length of open belt drive_____________
Length of open belt drive

17. Length of close belt drive_____________
Length of close belt drive

18. Pulleys___________________________
A pulley wheel is a mechanism which helps move or lift objects
Pulleys are usually used to reduce the amount of force needed to lift a load
Exercise machine pulley

19. Parts of Pulley system_______________
Direction of Force
Notice that the pulleys change the direction of the applied
force.

20. Types of Pulleys____________________
 fixed pulley
 moveable pulley
 block and tackle

21. Fixed Pulley_______________________
A fixed pulley has weight (the load) attached to one end of the rope and effort
applied to the other end.

22. Moveable pulley____________________
 In a movable pulley, the load is attached to the pulley and
one end of the rope is fixed to a support.
 rises and falls with the load being moved

23. Block and tackle____________________
Consists of two or more pulleys (fixed and moveable).
Block and tackle

24. Pulleys___________________________
The Pulley Advantage
In this simple pulley system,
the force is equal to the load,
so the Mechanical Advantage is 1:1 or 1.
The Mechanical Advantage is calculated like so:
Mechanical Advantage = Load / Effort = 100 N / 100 N
Mechanical Advantage = 1:1 or 1

25. Pulleys___________________________
The Pulley Advantage
Each side of the rope carries half the load.
Therefore, the force required by the person to
keep the load in equilibrium is also half the load.
10 Kg = 100 N

26. Thank You