The biggest disadvantage of belt transmissions and cable
transmissions is that the speed ratio remains constant but changes due to
slippage. As the chain drive is positive, there is no slippage, so the speed
ratio remains constant.
Chain transmissions are used in a wide range of power
transmission applications, such as bicycles, motorcycles, laminators,
agricultural machinery, machine tools, conveyors and coal cutters.
Chain transmissions consist of two wheels, a chain and called
as Sprockets. The sprockets is a tooth wheels with an endless chain.
There are different types of chains used in power transmission.
1. Roller Chain
2. Flat-top chain
3. Leaf Chain
4. Silent Chain
Regardless of the type of chain, the styles are classified
as follows:
- The direct link chain has alternative "external" and "internal" links.
- The offset link chain is similar for all links. These include integrated link chains such as bar links, flat caps, welded steel chains,
The roller chain is a chain commonly used for bicycles,
motorcycles, machine tools, etc. The silent chain is an inverted saw chain that
is widely used for smooth and quiet operation at low speeds.
Types of Chains:-
1. Roller Chains:-
This type of chain is most commonly used for the mechanical transmission of
energy from various types of domestic, industrial and agricultural machinery,
including conveyor belts, wire and tube wire drawing machines, presses,
automobiles, motorcycles and bicycles.
The roller chain consists of a series of short cylindrical
rollers joined together by side links. It is driven by a tooth wheels called a sprockets . It is a
simple, reliable and efficient power transmission.
These chains are typically smaller in diameter than the
height of the chain link plate. The link plate serves as a guide when the chain
is applied to the pinion,
The chain also acts as a guide to
support the material transported by way or method, such as the characteristics
of the conveyors and some bucket elevators. The roller chain is used for drive
and transport applications.
- The most commonly used chains for drives are the standard single chain standard roller chains. The nominal output capacity of this chain meets a wide range of transmission load requirements.
- Multiple chain roller chains are used to provide greater output capacity without the need to increase chain pitch or linear speed.
2. Flat-top chain:-
Flat top chains are widely used in conveyors and are mainly used for special
types of slate conveyors.
It consists of a flat upper chain.
· A series of steel caps with hinged barrels on each side.
· Insert a pin through the barrel to create a joint. They serve as beams and bearings.
· The pins are clamped or directed in the barrel of an upper plate and freely connected in the barrel of the next link.
· The connecting pin is normally knurled or wraps one end to hold the pin in a barrel of the top plate.
· Therefore, a continuous length of the flat upper chain is formed.
· Flat top chains are used only for transport.
3. Leaf Chain :- The blade chain is designed to lift instead of
power transmission. The tension is very high but slow. In general, chains work
intermittently. The key considerations in the design of leaf chains are the
tensile loads, the wear of the joints and the plates of union and the wear of
the sieve.
The blade chain is not hooked with the cogwheel because it
tends to get caught in the sprockets, so the tooth wheel cannot be attached.
Leaf chains often require very high loads, so they need a high elastic limit
and do not stretch permanently when subjected to large loads. The most common
use for leaf chains is probably in the forklift.
4. Silent Chain:- A chain of teeth, also called inverted tooth
chain, consists of a series of serrated link plates assembled to the joint part
so that they flex freely between each step.
The silent chain consists of accumulated rows of flat link
plates with a gear-type
contour designed to engage the teeth of the tooth wheel so that the rack
engages with the gear. The links can be held together at each chain joint by
one or more pins so that the chain can be bent.
Silent chains from other manufacturers are generally not
linked together. The standard silent chain is used in a variety of industrial
units that require a compact, fast, smooth and quiet unit.
High performance silent chains are available in various
sizes with pitch and width, and are used for ultra-fast units that require
exceptional smoothness and tranquility. This chain is commonly used in
industrial equipment where maximum smoothness is required.
Advantages and Disadvantages of Chain Drives:-
Advantages:-
· They are a positive impulse without candle.
· The efficiency is very high.
· It can be used for axes up to 3 m in distances between small and large centers.
· They allow high speed ratios of up to 8: 1 in one step.
· It can transmit more power than belt drive.
· Since the sprockets are lighter than the pulleys, the axles have less tension than belt drives.
· Unlike belt drives, they can work in extreme weather and temperature conditions.
· They take up less space and are more compact than belt drives.
· Lack of maintenance
Disadvantages:-
· The drive shaft and the driven shaft must be precisely aligned so that the axes are exactly parallel.
· More lubrication is required.
· High initial cost.
· If you pull your chain, you cannot turn it periodically.
· Speed fluctuations are greater.
