Chain drive: (Advantages and disadvantages)
Chain is a series of links connected by pin joints and mounted on sprockets for power transmission.
The chains does not slip over sprockets. They give constant velocity ratio. It is suggested to replace belt and rope if possible to get positive drive like chain. chains are made up of metals, that is why they take less space and they can be used for longer distance between shafts.
The wheel with teeth, which fit into the recesses of chain is known sprocket.
Following are the advantages of chain drives:
(a) No slippage between chain and sprocket.
(b) Almost negligible stretch.
(c) Maximum heavy loads can be carried.
(d) Long operating life.
(e) Operates in hostile environments like oily,dusty, water, etc.
(f) Can be replaced easily.
(g) Chains does not require initial tension.
(h) High efficiency upto 98% can be obtained.
(a) High noise during operation in certain types.
(b) Wearing of link and sprockets can take place.
(c) Flexibility is limited to a single plane.
(d) Sprockets are to be replaced after service.
(e) Chain drives need housing.
(f) Proper lubrication is needed.
(g) Proper alignment of shaft is basic requirement.
(h) Not suitable for nonparallel shafts.
Chain drives are popular in various application in almost all types of industries as well as automobiles. These are used for velocity ratio less than 10:1.
Chain are classified as:
(a) Roller Chain.
(b) Duplex Chain.
(c) Block Chain.
(d) Conveyor Chain.
(e) Silent chain.
Roller Chain:
These consist of number of inner link assemblies in which adjacent pairs are connected by outer links.
An inner link has two bushes on which rollers are mounted, followed by inner plate. This complete the inner link assembly. Such number of inner link assemblies are joined together by two outer plates from two sides with two bushes atleast 19 teeth are recommended for normal application sprocket.
Duplex Chain:
Duplex chain indicates simply combination of two chains in parallel to each other. The roller chains are designed on the basis of pitch and power transmitting capacity,
For more transmitting capacity, duplex, triplex or such chains are used.
Block Chain:
For low-speed power transmission, block chains are used. They can also be used as conveyor chains.
Conveyor Chain:
These type of chains are of hooks joints type. The sprocket is designed for smooth working of conveyor wheel. Chain is mounted on the sprocket and power is transmitted. These chains are used for material handling applications. They are designed for breaking load capacity rather than power and speed.
Silent Chain:
Silent chain offers little vibration and noise, and operates at 99% efficiency. These chains consists of a driving link, guide link and pins with joints. Silent chain drives are the best compared with roller chains because
(a) they have high power capacity,
(b) high speed,
(c) much quieter,
(d) high efficiency,
(f) more sprocket life.
Driving link is a plain link, engages sprocket teeth with less sliding and less impact.
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