this is the most helpful slide for mech engineers

1.  Definition and function of clutches.
 Operation of clutch.
 Classification of clutch.

2. A clutch is a mechanism which is used to
transmit the rotary motion from one shaft to
another shaft , whose axis is coincident with
first one.
The clutch is located between
the engine and gear box .When the clutch is
engaged , the power is transmitted from engine
to rear wheels through transmission system , and
the vehicle starts moving . On the other hand ,
when the clutch is disengaged , the power is
not transmitted to the rear wheel so the vehicle
stops moving.

3.  To permit proper engagement and
disengagement .
 To transmit smooth engine power to the wheels.
 To permit the shifting of gears without any
damage.

4. The clutch principle is based on the friction.when
the two frictional surfaces are brought in contact
and pressed,then they are united.if one is revolved the
other will also revolve.
When the driven member
is brought in contact with
driving member,it starts
rotating.When separated
it stops revolving.This is
how a clutch operates.

5. The clutch are classified in two categories :-
1) Positive clutches.
2) Gradual engagement clutches.

6. In this the clutches are either “in” (fig. 1) so that
the two shafts are rigidly connected and must
revolve at the same speed ; or it is “out”(fig.2)
when the shafts are disconnected . It is not
suitably used.

7. In this type of clutch it is possible for one
shaft to revolve , while other may be
stationary or revolving at low speed. As the
engagement occurs, the shafts are united and
speed becomes equal . Such clutch is also
known as “friction clutch”.

8.  Friction clutch :-
A. Cone clutch.
B. Single plate clutch.
C. Multi plate clutch.
 Other forms of clutch :-
A. Centrifugal clutch.

9. The cone clutch is consist of a flywheel and a cone
mounted on driving and driven shaft respectively .
The shape of side of flywheel facing cone is such to
unite the cone readily when the clutch is engaged.
The cone can be disengaged from flywheel by the
lever mechanism.
1. Flywheel .
2. Conical groove.
3. Friction lining.
4. Spring .
5. Lever mechanism.

10. It is consist of flywheel connected to the engine or driving shaft
and the driven shaft connected to transmission . Both are
connected through the spigot bearing . During disengaged
position the flywheel is free to rotate without linking the
clutch plate , but when the pressure is applied through the
lever mechanism , the clutch plate and flywheel are united
and the transmission occurs.

11. When a great amount of torque is to be transmitted instead of
single plate, a no of friction plates are used. This will
increase the no of mating surfaces , hence it is called the
“multi-plate clutch”.
These clutches are used in heavy
commercial vehicles , racing cars , etc.

12. In this type of clutch the centrifugal force instead of
spring force ,is used to keep it in engaged . Such
type of clutch is operated automatically depending
upon the engine speed . The vehicle can be started in
any gear.