Chapter 6 - Chains

Question 1

Chains

Answer 1

Transmission occurs by direct contact.
Friction is not a factor.
Most widely used type of mechanical element.
Used for power transmission and materials handling on conveyors.
High Torque, low cost.

Question 2

Advantages of Chain Drives

Answer 2

No slippage.
Carry very heavy loads.
100% Efficiency.
Unlimited Shelf life.
Not very affected by environment.
Repaired/Replaced easily.

Question 3

Disadvantages of Chain Drives

Answer 3

Only one plane.
Need Lubrication.
Precise alignment of shafts.
Generate High noise.
Elongation.
Lower Speed.
Sprocket needs to be replaced as well if chain not proper.

Question 4

Chains Materials:

Answer 4

Cast Iron.
Powder Metal.
Flame-cut Steel Plate.
Machined Metal.
Plastic.
Composites.

Question 5

Components of a Chain:

Answer 5

Roller Link.

Pin Link.

Question 6

Roller Link parts:

Answer 6

Roller Link Plate.
Roller.
Bushing.

Question 7

Pin Link parts:

Answer 7

Pin Link Plate.

Pin.

Question 8

Types of Chains

Answer 8

Single Stand Roller Chain.
Double Pitch Roller Chain.
Multiple Strand Roller Chain.

Question 9

Double Pitch Roller Chain

Answer 9

Contains half as many pitches as a regular chain, therefore is lighter and cheaper.
Suitable for long distances.

Question 10

Chain Nomenclature

Answer 10

Ex: 50 (5/8" pitch, usual properties)
Last # means properties:
0 - Normal
1 - Lightweight
5 - Roller less bushing
First #s mean #/8" pitch and #/16" width
H on the end means Heavy

Question 11

Double Pitch Chain Nomenclature

Answer 11

Same as Single Chain, but add 20 in the front. Also need to multiply the pitch by 2.

Question 12

Multiple Strand Roller Chain

Answer 12

Multiples of the same chains put side by side.

Run at high speeds and carry more load.

Question 13

Sprockets for Multiple Strand Roller Chains

Answer 13

Sprockets can be single-cut (one tooth per link) or double-cut (two teeth per link).
Cuts down on the wear rate by half.

Question 14

Multiple Strand Roller Chain Nomenclature

Answer 14

Same as for Single or Double, but has a -# so signify the number of chains attached.

Question 15

Specific Application Data for Chains

Answer 15

Horsepower
Shaft speeds
Load and power source
Shaft Diameters
Center Distance
Chain Length
Space Limitations
Surrounding Conditions

Question 16

Chain and Sprocket Selection Process:

Answer 16

1. Service Factor
2. Computation of Design HP
3. Tentative Chain Selection
4. Final selection of roller chain and small sprocket.
5. Selection of the large sprocket.
6. Drives with higher chain tension or smaller sprocket requirements.
7. Chain Length
8. Final center distance calculation.

Question 17

Addition Design Features

Answer 17

Relative Shaft Positions
Lubrication
Chain Castings
Chain Idler

Question 18

Conveyor Chain

Answer 18

Roller Chain used for pulling loads at slower speeds.

Rated in terms of Breaking Load.

Question 19

Silent Chains

Answer 19

Has teeth in the chain and engage with the teeth of the sprocket, this creates less impact and results in a quieter operation.
95-99% efficiency.

Question 20

Silent Chains Nomenclature

Answer 20

1. SC302 (Silent Chain, 3/8” pitch, 2/4” width)

2. SC0315 (Silent Chain, 03=3/16” pitch, 15/32” wide)

Question 21

Engineering Chains Types:

Answer 21

Straight sidebar steel chains(with rollers or roller less).
Offset sidebar steel chains(with rollers or roller less).
Bar-link chains
Welded steel chains
Open barrel steel pintle chains

Question 22

Chain Sprockets

Answer 22

Very important when selecting the right chain.

Classified as precision or semi-precision.

Question 23

Sprocket Types

Answer 23

Type A - no hubs
Type B - hub on one side
Type C - hubs on two sides
Type D - has detachable hub
Can be Single-cut or Double-cut

Question 24

Sprocket teeth requirements:

Answer 24

> 100RPM large pitch - >=15 teeth
100RPM small pitch - >=17 teeth
Normal apps >= 19 teeth
Impulse apps >=23 teeth

Question 25

Chain Lubrication Methods:

Answer 25

Manual (brush, aerosol can)
Drip
Oil Bath
Pressurized Spray

Question 26

As pitch ^ :

Answer 26

Strength ^
Capacity ^
Weight ^

Question 27

What must mach between sprockets and chain

Answer 27

Pitch

Question 28

Most manufactures form even # of _____, but odd # of _____.

Answer 28

Pitches, teeth.