732 Theory of Machines
2. Materials for Brake Lining.
3. Types of Brakes.
4. Single Block or Shoe Brake.
5. Pivoted Block or Shoe Brake.
6. Double Block or Shoe Brake.
7. Simple Band Brake.
8. Differential Band Brake.
9. Band and Block Brake.
10. Internal Expanding Brake.
11. Braking of a Vehicle.
13. Types of Dynamometers.
14. Classification of Absorption
15. Prony Brake Dynamometer.
16. Rope Brake Dynamometers.
17. Classification of Transmission
19. Belt Transmission
20. Torsion Dynamometer.
21. Bevis Gibson Flash Light
A brake is a device by means of which artificial
frictional resistance is applied to a moving machine member,
in order to retard or stop the motion of a machine. In the process
of performing this function, the brake absorbs either kinetic
energy of the moving member or potential energy given up by
objects being lowered by hoists, elevators etc. The energy
absorbed by brakes is dissipated in the form of heat. This heat
is dissipated in the surrounding air (or water which is circulated
through the passages in the brake drum) so that excessive
heating of the brake lining does not take place. The capacity of
a brake depends upon the following factors :
1. The unit pressure between the braking surfaces,
2. The coefficient of friction between the braking
3. The peripheral velocity of the brake drum,
4. The projected area of the friction surfaces, and
5. The ability of the brake to dissipate heat equivalent
to the energy being absorbed.
The major functional difference between a clutch and
a brake is that a clutch is used to keep the driving and driven
member moving together, whereas brakes are used to stop a
moving member or to control its speed.
19.2. Materials for Brake Lining
The material used for the brake lining should have the
following characteristics :