CHAIN DRIVES PPT

Question 1

In order to avoid slipping, unlike in belt and rope drives where slipping may occur, __________ are used.

Answer 1

steel chains

Question 2

are made up of number of rigid links which are hinged together by pin joints in order to provide the necessary flexibility for wraping round the driving and driven wheels.

Answer 2

Chains

Question 3

These wheels have projecting teeth of special profile and
fit into the corresponding recesses in the links of the
chain.

These toothed wheels are known as _________ wheels or
simply _________.

Answer 3

sprockets

Question 4

The chains may also be used for long center distance of up to

Answer 4

8 metres

Question 5

The chains are used for velocities up to ________ and for power up to ________.

Answer 5

25 m/s, 110 kW

Question 6

the distance between the hinge centre of a link and the corresponding hinge centre of the adjacent link

Answer 6

Pitch of chain, p

Question 7

the diameter of the circle on which the hinge centers of the chain lie, when the chain is wrapped around a sprocket.

Answer 7

Pitch circle diameter of chain sprocket, D

Question 8

The value of C obtained should be decreased by _________ in order to accommodate initial sag in the chain.

Answer 8

2 to 5 mm

Question 9

For best results, the minimum center distance should be ___________ the pitch.

Answer 9

30 to 50 times

Question 10

Used for ________ and __________ purposes and operate at a
maximum velocity of 0.25 m / s.

Answer 10

Hoisting and Hauling Chains

Question 11

The links of this type of chain are of oval shape; joint of each link is welded. The sprockets which are used for this type of chain have receptacles to receive the links.

Answer 11

Chain with oval links

Question 12

The links of this type of chain are of square shape. Such type of chains are used in hoists, cranes, dredges. The manufacturing cost is less than that of chain with oval links, but in these chains, the kinking occurs easily on overloading.

Answer 12

Chain with square links

Question 13

These chains are used for elevating and conveying the
materials continuously at a speed up to 2 m / s.
* The ___________ run at slow speeds of about 0.8 to
3 m / s.
* The ____________ are of the following two types:
1. Detachable or hook joint type chain and
2. Closed joint type chain

Answer 13

Conveyor Chains

Question 14

These chains are used for transmission of power, when the distance between the centres of shafts is short.

These chains have provision for efficient lubrication

Answer 14

Power Transmitting Chains

Question 15

This was used in the early stages of development in the power transmission. It produces noise when approaching or leaving the teeth of the sprocket because of rubbing between the teeth and the links. These chains are used mainly for conveyor application at small speed

Answer 15

Block or bush chain

Question 16

(also known as inverted tooth chain) is designed to eliminate the adverse effects caused by stretching, and when properly lubricated, this chain gives durable service and runs very smoothly and quietly.

• There is no relative sliding between the teeth of the inverted tooth chain and the sprocket wheel teeth.
• The economical speed is of the order 4000 fpm (20 m/s).

Answer 16

Silent chain

Question 17

consists of outer plates or pin link plates, inner plates or roller link plates, pins, bushes and rollers.
* A pin passes through the bush which is secured in the holes of the roller between the two sides of the chain.
* The rollers are free to rotate on the bush which protect the sprocket wheel teeth against wear.
* The pins, bushes and rollers are made of alloy steel.
* The economical speed is of the order 2500 fpm (13 m/s).

Answer 17

Bush roller chain

Question 18

In order to have smooth operation, the minimum number of teeth on the smaller sprocket or driver sprocket may
be taken as _____ for moderate speeds and _____ for high
speeds; or preferably ____ teeth.

Answer 18

17, 21, 24

Question 19

The angle through which a chain link turns on its pin as it engages with the sprocket is equal to

Answer 19

180 / T

Question 20

From an operating standpoint, ___________ is desirable

Answer 20

large sprocket

Question 21

It is usually preferable to use __________ of teeth on a sprocket.

Answer 21

odd number

Question 22

For the number of teeth of the small sprocket, it is recommended to use not fewer than ____ and preferably not fewer than _____.

Answer 22

11, 24

Question 23

In the chain number: the right-hand digit ___ indicates a rollerless bushing chain

Answer 23

5

Question 24

In the chain number: the right-hand digit

___ indicates a lightweight chain

Answer 24

1

Question 25

In the chain number: the right-hand digit ___ indicates a chain of usual proportion with roller.

Answer 25

0

Question 26

Oil applied periodically with brush or spout can (100 fpm maximum chain speed)

Answer 26

Type I. Manual Lubrication

Question 27

Oil applied between link plate edges from a drip lubricator (300 fpm maximum)

Answer 27

Type II. Drip Lubrication

Question 28

Oil level maintained at predetermined height in casing (1000 fpm maximum)

Answer 28

Type III. Oil Bath or Oil Slinger

Question 29

The range of chain widths should be between p and 10p, but preferably between ___ and ____.

Answer 29

2p and 6p

Question 30

In small sprockets, it is necessary to determine whether the number of teeth and the pitch selected will result in a sprocket large enough to be mounted on the shaft with due allowance for a keyway. On this basis, the following relations may be used to determine the minimum number of teeth that may be used with a given pitch for a sprocket with bore d.

Answer 30

Maximum Sprocket Bore

Question 31

The length in links should be used as an even number unless it is desired to use an ________ An advantage of the _________ is that the adjustment of center distance may be in units of one link instead of a pair of links.

Answer 31

offset or hunting link

Question 32

* Means of adjusting center distance should be provided to secure proper chain tension when the drive is installed and to make adjustments for wear of the chain in service. * There should be a small amount of slack in the chain. * Idler sprockets may be used to minimize the slack of the chain to be installed on the slack side.

Answer 32

Adjustment for Chain Tension

Question 33

Chain drives should be enclosed to provide proper chain lubrication, to keep dirt and grit from the chain and sprocket and to ensure the safety of the operator. * The case should be easy to install and to open for inspection, maintenance and lubrication.

Answer 33

Chain Cases and Lubrication