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1. Elements of theory of machine & machine design
Submitted By: Submitted To:
Mizanur Rarman Sabuj Zulfa Fredous
Id No:2016000400022
Topic Name :

2. Introduction
Power transmission is the movement of energy from its place of generation to
a location where it is applied to perform useful work.
Power is defined formally as units of energy per unit time. In SI units:
Watt =

3. Types Of Power Transmission
1.Belt
2.Rope
3.chain

4. Belts
• A Belt Is A Loop Of Flexible Material Used To Link Two Or More Rotating Shafts
Mechanically, 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.
• In A Two Pulley System, The Belt Can Either Drive The Pulleys Normally In One Direction
(The Same If On Parallel Shafts), Or The Belt May Be Crossed, So That The Direction Of
The Driven Shaft Is Reversed (The Opposite Direction To The Driver If On Parallel
Shafts). As A Source Of Motion, A Conveyor Belt Is One Application Where The Belt Is
Adapted To Carry A Load Continuously Between Two Points.

5. Types Of Belt Drive
1.flat belt 2.vee belt 3.triming belt 4.round belt

6. Selection Of Belt Drive
• Speed of the driving and driven shafts,
• Speed reduction ratio,
• Power to be transmitted,
• Centre distance between the shafts,
• Positive drive requirements,
• Shafts layout,
• Space availability

7. Arrangement Of Belt Drive
Open belt drives: Crossed belt drives:

8. Types Of Belt Drive
• Leather belts
• Cotton or fabric belts
• Rubber belt
• Balata belts
• Plastic belt

9. Power Transmission By Belt Drive
• Belts are the cheapest utility for power transmission between shafts that may
not be axially aligned. Power transmission is achieved by specially designed
belts and pulleys. The demands on a belt-drive transmission system are huge,
and this has led to many variations on the theme. They run smoothly and
with little noise, and cushion motor and bearings against load changes, albeit
with less strength than gears or chains. However, improvements in belt
engineering allow use of belts in systems that only formerly allowed chains
or gears.
• Power transmitted between a belt and a pulley is expressed as the product of
difference of tension and belt velocity

10. Rope Drives
A Rope Drive uses a rope to transmit power from one system to another, for eg. in pulleys over a
well.
It is different from a belt drive because it does not use a belt to transmit power.
A chain drive uses a chain to transmit power, as in a bicycle. A rope drive is expected to give a
smoother operation and less noise than chain drive, but can have higher power losses.

11. Types Of Rope Drive
Fibre ropes
Wire ropes

12. Fibre Ropes
• These are made up from fiber material such as hemp, manila and cotton. The hemp
and manila ropes are lubricated with a tar. The cotton rope is very soft. Therefore
no lubrication is required. These drive is used for 60 meter distance between two
shaft.
• There are two classification of fiber rope –
• Vegetable fiber – This fiber contain hemp, sisalana, henequen, cotton, jute and
coir.
• Synthetic fiber – Nylon is the core composition of the synthetic fiber, usually the
tensile strength of nylon is almost three times of vegetable fiber.

13. WIRE ROPES
This type of rope s used when the shaft or pulley distance are up to 150 meter apart. These
are made by twisting the thin metal steel wire which increases the strength of rope.

14. Chain Drive
• Chain drives consist of an endless series of chain links that mesh with
toothed sprockets. Chain sprockets are locked to the shafts of the driver and
driven machinery. Chain drives represent a form of flexible gearing. The
chain acts like an endless gear rack, while the sprockets are similar to pinion
gears.
• Chain drives provide a positive form of power transmission. The links of the
chain mesh with the teeth of the sprockets and this action maintains a
positive speed ratio between the driver and driven sprockets.

15. Types Of Power Transmission Chain
• Block chain
• Roller chain
• Inverted tooth chain

16. Conclusion
• Power transmission is the movement of energy from its place of generation
to a location where it is applied to perform useful work.
•