What is Chain Drive and its Types?

What is Chain Drive?

A chain drive is a way of transmitting mechanical power from one place to another. It is often used to convey power to the wheels of a vehicle, particularly bicycles and motorcycles. It is also used in a wide variety of machines besides vehicles.

Most often, the power is conveyed by a roller chain, known as the drive chain or transmission chain, passing over a sprocket gear, with the teeth of the gear meshing with the holes in the links of the chain. The gear is turned, and this pulls the chain putting mechanical force into the system.

Chain drive, Device widely used for the transmission of power where shafts are separated at distances greater than that for which gears are practical. In such cases, sprockets take the place of gears and drive one another by means of a chain passing over the sprocket teeth.

The chains used in conveyor belts are commonly blockchains and consist of solid or laminated blocks connected by side plates and pins. The blocks engage with teeth on sprocket wheels. Depending on the material being moved, buckets, hooks, or other devices are connected to the blocks.

The chains are made up of a number of rigid links that are hinged together by pin joints to provide the flexibility needed to wrap driving and driven wheels.

These wheels have special profile teeth and fit the corresponding recess in the chain link. Toothed wheels are known as sprocket wheels or bus sprockets. Sprockets and chains are thus constrained to move together without sliding and ensure the correct velocity ratio.

Chain Drive

Chains are mostly used to transfer speed and power from one shaft to another when the center distance between their shafts is short such as bicycles, motorcycles, agricultural machinery, conveyors, rolling mills, road rollers, etc.

The chain can also be used for long center distances of up to 8 metros. Chains are used for velocities up to 25 m/s and power up to 110 kW. In some cases, high power transmission is also possible.

Terminology of Chain Drive

  • Chain pitch: This is the distance between the hinge center of a link and the corresponding hinge center of an adjacent link. It is usually denoted by p.
  • Pitch circle diameter of chain sprocket: This is the diameter of the circle on which the hinge centers of the chain lie when the chain is wrapped with a ball. The hinge centers of the chain and the circle drawn through these centers are called pitch circles and its diameter is known as pitch circle diameter.

Types of Chain Drive

Following are the three types of chain drive:

  • Hoisting and hauling chain drive
  • Conveyor chain drive
  • A power transmitting chain drive

Hoisting and Hauling Chain

A hoist is a device for raising or lowering a load using a drum or a lifting wheel around which a rope or chain is wound. It can be operated manually, electrically, or pneumatically and can use chain, fiber, or wire ropes as a lifting medium. The best-known form is an elevator, the carriage of which is raised and lowered by a lifting mechanism. Most hoists are attached to their loads with a lifting hook.

These chains are used for hoisting and hail and operate at a maximum velocity of 0.25 m/s. Hoisting and ruling chain are of the following two types:

  • Chain with oval links: This type of chain link is oval-shaped. Each link joint is welded. The sprockets used for this type of chain have receptors to obtain the link. These types of chains are used only at low speeds such as in-chain hoists and anchors for marine operations.
  • Chains with square links: The links of this type of chain are square-shaped. Such chains are used in hoists, cranes, dredges. The manufacturing cost of this type of chain is less than a chain with oval links, but in these chains, overloading is easily kinking.

Conveyor chain

A conveyor chain is a chain that has been specially developed for chain conveyor systems. It consists of a series of plain bearings that are held together by connecting plates. Each bearing consists of a pin and a bushing on which the chain roller rotates.

These chains are used to continuously lift and convey materials at speeds up to 2 m/s. There are two types of conveyor chains:

  • Detachable or hook joint type chain: This type of conveyor chain is used in a conveyor where the length between power transmissions is short.
  • Closed joint type chain: This type of chain consists of a barrel and link and is made into a single casting, then the chain is heat-treated to provide high strength.
Conveyor Chain drive

Conveyor chains are usually made of malleable cast iron. These chains do not have smooth running properties. The conveyor chain operates at a slow speed of about 0.8 to 3 m/s.

Power Transmitting Chain

power transmission chains are used for the transmission of mechanical power when the distance between the centers of shafts is short. These chains have provisions for efficient lubrication. The power transmitting chains are of the following three types.

  1. Block or bush chain
  2. Bush roller chain
  3. Silent Chain

1) Block or bush chain

This type of chain was used in the initial stage of development in power transmission. It causes noise when rubbing between the teeth and the link when the sprocket is near or exiting the teeth. These types of chains are used to some extent at small speeds as conveyor chains.

block chains

2) Bush Roller Chain

A bush roller chain consists of an outer plate or pin link plate, inner plate or roller link plate, pins, bushes, and rollers. A pin passes through the bushing which is secured in the hole of the roller between the two sides of the chain. The rollers are free to rotate on the bush which protects the sprocket wheel teeth against wear. Pins, bushes, and rollers are made of alloy steel.

A bush roller chain is extremely strong and simple to manufacture. It serves well in severe conditions. There is a slight noise with this chain due to the impact of the rollers on the teeth of the sprocket wheel. This chain can be used where there is slight lubrication.

Bush roller Chains

When one of these chains becomes slightly elongated due to wear and stretch of parts, the extended chain sprocket is greater than the pitch of the wheel teeth. The rollers fit unevenly in the cavities of the wheel. The result is that the total weight falls on one tooth or a few teeth. Stretching of parts increases the wear of roller surfaces and sprocket wheel teeth.

Roller chains are standardized and manufactured on a pitch basis. These chains are available in single-row or multi-row roller chains such as simplex, duplex, or a triple strand.

3) Silent chain

A silent chain, also known as an inverted tooth chain. It is designed to eliminate the bad effects caused by stretching and to create noiseless walking. When the chain is stretched and the pitch of the chain increases, the links ride on the teeth of the sprocket wheel in a slightly increased radius.

This automatically corrects small changes in pitch. There is no relative sliding between the teeth of the inverted tooth chain and the sprocket wheel. When properly lubricated, this chain gives durable service and runs very smoothly and quietly.

Advantages and Disadvantages of Chain Drive over Belt or Rope Drive

Following are the advantages and disadvantages of chain drive over belt or rope drive:

Advantages of Chain Drive

  • Chain drives have a low maintenance cost
  • They give a high transmission efficiency of up to 98 percent.
  • No-slip and creep during the power transmission, ensure the perfect velocity ratio. The output side rotates at a precise speed.
  • It produces less stress on the shaft because the sprockets are lighter than pulleys.
  • Highly efficient, chain drives gives the advantage of more power compared to belt drive.
  • Chain drive, the speed ratio is good as compared to belt drive.
  • It can be used in reversing drives.
  • It can be operated at a high temperature Like a belt that cants not operate at high temperatures.
  • It can be used for both small and large center distances
  • Chain drive can operate in wet conditions too.
  • It can withstand abrasive conditions.
  • The chain drive is easy to install.
  • Initial tension is not required in the chain drive.
  • Even in fire hazards it does not faces any bad problem.
  • Multiple hafts can be driven from a single chain drive.
  • A chain drive requires less space and is more compact than a belt drive.

Disadvantages of Chain drive

  • The major disadvantages are here it requires more and frequent lubrication otherwise rust problem comes.
  • The installation or initial cost is more.
  • It cannot be used where there is a requirement of slips.
  • We can’t keep the chain drive-in open. It needs housing or covering.
  • It cannot be used for précised motion requirements.
  • It is noisy and therefore there is a problem of vibration too.
  • The velocity fluctuation is more.

Application of chain drive

Chain drives are used in many types of industrial applications, such as:

  • Rigging and moving heavy materials
  • Hydraulic lift truck fork operation
  • Increasing or decreasing a driver’s output speed by altering gear ratios between the driver and the sprocket being driven
  • Overhead hoists
  • Operating conveyor belts
  • Chain drive used for transmission of power.
  • This is also used in woodworking machinery.
  • Chain drive used in several industries for several purposes like Transportation Industry, Agriculture Machinery, Material Handling Equipment, Building construction.

FAQ

1. What is Chain Drive?

A chain drive is a way of transmitting mechanical power from one place to another. It is often used to convey power to the wheels of a vehicle, particularly bicycles and motorcycles. It is also used in a wide variety of machines besides vehicles.

2. What are the types of chain drives?

Following are the three types of chain drive:

1. Hoisting and hauling chain drive
2. Conveyor chain drive
3. A power transmitting chain drive

3. What is the application of chain drive?

Chain drives have many types of industrial applications, such as:

1. Rigging and moving heavy materials.
2. Hydraulic lift truck fork operation.
3. Overhead hoists.
4. Operating conveyor belts.
5. Increasing or decreasing a driver’s output speed by altering gear ratios between the driver and the sprocket being driven.

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