This is presentation I made an assignment assigned to me in the subject of Basic Mechanical Engineering. My this presentation was recognized as best among my class. I'm thankful to my subject teacher Sir Shreesh Dhavle for the guidance.

1. BELT DRIVES

2. A belt is a looped strip of flexible
material used to mechanically link two
or more rotating shafts. A belt drive
offers smooth transmission of power
between shafts at a considerable
distance.
Belt drives are used as the source
of motion to transmit power
efficiently or to track relative
movement.

3. • Power is to be transmitted between
parallel shafts. The belt transmits
torque from the driving pulley to
the driven pulley by means of the
forces of friction that arise between
the taut belt and the pulleys.
• Rotary motion is transmitted
between driving pulley to driven
pulley

4. OPEN BELT DRIVE CROSSED BELT DRIVE COMPOUND BELT
DRIVE
RIGHT ANGLE
DRIVE
QUARTER TWIST
DRIVE

5. An open belt drive
is used to rotate
the driven pulley
in the same
direction of
driving pulley.

6. In the motion of belt drive, power transmission results
make one side of pulley more tightened compared to the
other side. In horizontal drives, tightened side is always
kept on the lower side of two pulleys because the sag of
the upper side slightly increases the angle of folding of the
belt on the two pulleys.
The open belt drive, as shown in figure, is used with
shafts arranged parallel and rotating in the same
direction. In, this case, the driver A pulls the belt from
one side (i.e. lower side RQ) and delivers it to the other
side (i.e. LM). Thus the tension in the lower side belt will
be more than that in the upper side belt.
The lower side is known as tight side whereas the upper
side belt is known as the slack side.

7. A crossed belt drive is
used to rotate driven
pulley in the opposite
direction of driving
pulley.

8. Higher the value of wrap enables more
power can be transmitted than an open
belt drive. However, bending and wear of
the belt are important concerns.
The crossed or twist belt drive, is used with
shafts arranged parallel and rotating in the
opposite directions. In this case, the driver pulls
the belt from one side(i.e. RQ) and delivers it to
the other side(i.e. LM). Thus the tension in the
belt RQ will be more than that in the belt LM.
The belt RQ is known as tight side, whereas the
belt LM is known as slack side.

10. A compound belt drive is
used once when power is
transmitted from one shaft to
another through a variety of
pulleys.

11. The belts are connected in such a way
that the driver moving one system of
drives is simultaneously moving the
other connected system.
It is used when the distance between
input and output shaft is very large.

12. • Belt drives are simple are economical.
• Belts drives are provided with overload
and jam protection.
• Noise and vibration are damped out.
Machinery life is increased because load
fluctuations are shock-absorbed.
• They are lubrication-free. They require
less maintenance cost.
• Belt drives are highly efficient in use (up
to 98%, usually 95%).
• They are very economical when the
distance between shafts is very large.
• In Belt drives, angular velocity ratio is
not necessarily constant or equal to the
ratio of pulley diameters, because
of slipping and stretching.
• Heat buildup occurs. Speed is limited to
usually 35 meters per second. Power
transmission is limited to 370 kilowatts.
• Operating temperatures are usually
restricted to –35 to 85°C.
• Some adjustment of center distance or
use of an idler pulley is necessary for
wearing and stretching of belt drive
compensation.

14. Made by :
Pulkit Chandel (17070123078)
Symbiosis Institute of Technology
GUIDED BY :
Sir Shreesh V Dhavle
Department of
Mechanical Engineering