The document discusses various types of couplings, clutches, and brakes used for power transmission. It describes rigid couplings like sleeve, split muff, and flange couplings that connect shafts in perfect alignment. Flexible couplings like bush pin, Oldham, and universal joints are also covered, which allow for some misalignment between shafts. Various clutches and brakes used to control motion like disc, cone, centrifugal, band, and internal shoe brakes are also summarized.

1.  Couplings and Clutches are power and motion
transmission elements.
They are used to transmit power from one shaft
to another shaft.
The brake is a frictional device which is used to
control the motion.

2. Classification of Couplings
Couplings
Rigid
Coupling
Sleeve or Muff
Coupling
Split Muff
Coupling
Flange
Coupling
Flexible
Coupling
Bushed pin type
flange
Coupling
Oldham
Coupling
Universal
Coupling

3. Rigid couplings
 Rigid Couplings are used to connect two shafts which are
perfectly in axial alignment.
Sleeve or Muff Coupling
Construction:
 It is the simplest type of rigid coupling which is made from
cast iron.
 The hollow cylinder (muff) is fitted over the ends of the two
shafts with the help of taper sunk key.
Working:
 Disadvantage: It is difficult to assemble when there is no
perfect alignment between shafts.

4. Sleeve or Muff Coupling

6. Rigid couplings
Split Muff Coupling
Construction:
 The muff or sleeve is made into two halves of cast iron.
 They both are joined by nut and bolts.
Advantage:
 Assembling and disassembling of the coupling is possible
without the changing the position of shaft.
Application:
 This coupling is used for heavy power transmission at
moderate speed.

7. Split Muff Coupling

9. Rigid couplings
Flange Coupling
 This coupling is having two
separate cast iron flanges.
 The flanges can be of
protected type or
unprotected type.
 The flange couplings are
rigid and accurate.
 It is used for heavy power
transmission at low speed.

10. Flange couplings

11. Protected type flange couplings

12. Flexible couplings
 Flexible couplings are used to protect the driving and
driven machines from effect of shocks, excessive stresses
due to deflection and vibration which may arise from
misalignment of shafts.
Bushed pin type flange coupling
 This type of coupling allows for imperfect alignment of two
joining shaft.
 This type of coupling has pins which works as a coupling
bolt. The rubber or leather bushes are used over pins.
Rubber bush absorbs shocks and vibrations during
operation.
 It is generally used to couple electric motor and machine.

13. Flexible couplings

14. Bushed pin type flange coupling

15. Flexible couplings
Oldham’s Coupling
 It is used in connecting two
parallel shafts whose axes are
at small distance apart.
 The flanges have projections
and disc is provided with two
slots on both sides which are
right angle to each other.
 The rotation of drive shaft
causes the rotation and sliding
of disc which transmits the
motion and power to the
driven shaft.

16. Oldham’s Coupling

17. Flexible couplings
Universal Coupling
Construction:
Working:
Application:
 This coupling is used to
connect two shafts whose axes
will intersect.
 The angle between the shaft
axes may vary slightly during
operation.
 It is widely used in automobile
and machine tools.

18. Universal Coupling

19. CLUTCHES
 Clutch is a form of coupling which is used to
transmit the power from driver shaft or an input
shaft to driven shaft of machine which may be
required to start or stop frequently.

20. CLUTCHES
Clutches
Mechanical
Positive
Clutches
Jaw Clutch
Toothed Clutch
Electromagnetic Pneumatic Hydraulic
Friction
Clutches
Disc Clutch
Cone Clutch
Centrifugal
Clutch

21. CLUTCHES
 Jaw & Toothed Clutch
 This type of clutch provides
engagement without slippage.
 The jaw clutch consists of segmental
projections or dogs on one side of
flange and corresponding recess on
other side of flange.
 Driving flange is rigidly attached to the
end of driving shaft while the other
flange is keyed to the other shaft by
feather key so it can slide on the shaft.
 The shifting device is accommodated
on the hub of the sliding flange.
 Automobiles and Tractors

22. CLUTCHES

23. Jaw & Toothed Clutch

24. CLUTCHES
Disc Clutch
 There are two flanges in such type of clutches.
One rigidly keyed to driving shaft and other fitted to driven
shaft by feather key or splines.
The amount of torque transmitted depends upon axial
pressure, radius of the friction surfaces and coefficient of
friction.
Automobiles
When large torque transmission is required the multidisc
clutches are used. It is having more number of contact
surfaces discs on driving and driven shaft.

25. Disc Clutch

26. Disc Clutch

27. CLUTCHES
Cone Clutch
 The clutch consists of an internal cone fixed to the driving
member and a movable cone free to slide axially is keyed
to the driven member.
 The slope of cone is from 8º to 15º.
 The clutch parts are held together by springs producing
required axial force.
Advantage of cone clutch over the disc clutch is very
simple and required less axial pressure to disengaged the
clutch.

28. CLUTCHES

30. Cone Clutch

31. CLUTCHES
Centrifugal Clutch
 In this clutch the engagement and
dis-engagement takes place at
certain running speed.
 The shoes are held against the hub
or spider on the driving shaft by
means of suitable springs.
 The driven member consists of a
cylindrical drum in which shoes
slide to make the contact through
friction surfaces with inner linings
of drum due to centrifugal force on
the shoes.

32. Centrifugal Clutch

33. BRAKES
It is a device by means of which frictional
resistance is applied to a moving machine member
in order to retard or stop the motion of a machine.
Brakes are used in automobiles, trains, vehicles,
hoists, elevators, presses, etc.
Brakes absorbs kinetic energy of moving member
in automobiles and brakes absorbs potential
energy of lowering member in hoists or elevator
brake.

34. BRAKES
Brakes
Mechanical
Block Brake Band Brake
Hydraulic Electrical
External and
Internal shoe
Brake

35. BRAKES
Block Brake
 This brake consists of blocks which are pressed against
the rim of revolving brake wheel or drum.
 The friction between the wheel and the blocks tend to
prevent the rotation of the wheel.
 Single Block :Railway train, Tram. Prony brake is an
example of block brake.
Double block :Electric cranes.
 Bicycle brake is an example of double block brake.

38. BRAKES
Band Brake
A band brake consists of a flexible band of leather or steel
lined with friction material.
 The friction between the band and the wheel surface
provides the braking force to decrease or stop the motion
of the wheel.
 This type of brakes are used in civil construction
equipments and also in automobiles as hand brake.
 Simple band brakes and differential band brakes.

39. Simple band
brakes

40. Differential band brakes

41. BRAKES
 Internal Expanding shoe Brake
 The shoes are housed in the rotating
drum.
 Under released condition, sufficient
gap between shoes and inner surface
of drum is maintained.
 The rotation of cam tends to expand
the shoes outwards eliminating gap
and making contact between the
shoes and inner surface of the
rotating drum.
 Applications are in motor cars and
light trucks.

43. Difference between a brake and a clutch