ROLLER CHAIN

Question 1

BASIC FEATURES OF CHAIN DRIVES

Answer 1

BASIC FEATURES OF CHAIN DRIVES (Budynas-Nisbett, 2008)
 constant ratio, since no slippage or creep is involved
 long life
 ability to drive several shafts from a single source of power

BASIC FEATURES OF CHAIN DRIVES (Shigley & Mischke, 1996)
 Can span long center distances like belts, and positively transmit speed and
torque like gears
 More compact than belt drives, but less compact than gear drives (for a given
ratio and power capacity)
 Mounting and alignment do not need to be as precise as for gear drives.
 Usually less expensive than gear drives and quite competitive with belt drives.

Question 2

specially designed for use in materials handling and conveyor
equipment and is characterized by its long pitch, large roller diameters and high tensile strength (Childs, 2004).

Answer 2

Conveyor Chain

Question 3

Generally used for load balancing applications and is essentially a
special form of transmission chain (Childs, 2004).

Answer 3

Leaf Chain

Question 4

It is an inverted tooth chain. It can operate more quietly and at
higher speeds than comparatively sized roller chain (Childs, 2004).

Answer 4

Silent Chain

Question 5

It is probably the most commonly used in a wide variety of low-
speed to high-speed drives (Shigley and Mischke, 1996).

Answer 5

Roller Chain

Question 6

power transmission device consisting of a series of pin-connected links.

Answer 6

Chain

Question 7

toothed wheel which meshes with a chain to transmit motion or power.

Answer 7

Sprocket

Question 8

It is an assembly of alternating roller links and pin links in which the
pins pivot inside the bushings, and the rollers, or bushings, engage the sprocket teeth
to positively transmit power.

Answer 8

Roller Chain

Question 9

Distance between
centers of adjacent
joint members.

Answer 9

Chain Pitch

Question 10

Chain Materials

Answer 10

 Steel for common applications
 Stainless / surface treated / chemical resistant steels for corrosive
environments

Question 11

Chain Markings

Answer 11

Chain Markings
- Chain number designation
- Manufacturer’s name and/or its trademark

Question 12

have precisely designed, radiused pockets which smoothly engage
the rollers on the chain and positively transmit torque and motion (Shigley and
Mischke, 1996).

Answer 12

Sprockets

Question 13

Sprocket Material (Shigley and Mischke, 1996)
- The ??? the number of teeth on the sprocket, the ??? the tooth loading.
Sprocket teeth should be hardened when the number of teeth is less than 25 and any of
the following conditions exist:

Answer 13

• fewer
• higher

1. The drive is heavily loaded
2. The drive runs at high speeds
3. The drive runs in abrasive conditions
4. The drive requires extremely long life

Question 14

Chain Lubrication (Shigley and Mischke, 1996)
Effective lubrication aids chain performance and life in several ways:

Answer 14

1. By resisting wear between the pin and bushing surfaces
2. By flushing away wear debris and foreign materials
3. By lubricating the chain-sprocket contact surfaces
4. By dissipating heat
5. By cushioning impact loads
6. By retarding rust and corrosion

Question 15

Essential Lubricant Properties (Shigley and Mischke, 1996)

Answer 15

 Low enough viscosity to penetrate to critical surfaces
 High enough viscosity to maintain an effective lubricating film at prevailing
bearing pressures
 Free of contaminants and corrosive substances
 Able to maintain lubricating properties in the full range of operating
conditions

Question 16

Recommended Lubricants

Answer 16

Recommended Grade / Temperature ,°C

SAE 5 / -45 to 10
SAE 10 / -29 to 26
SAE 20 / -12 to 43
SAE 30 / -6 to 54
SAE 40 / -1 to 60
SAE 50 / 4 to 65

Question 17

Efficiency of common roller chain drives:

Answer 17

95%-99%

Question 18

Power Rating of Chains

Answer 18

The capacities of chains are based on the following:
• 15 000 h at full load
• Single strand
• ANSI proportions
• Service factor of unity
• 100 pitches in length
• Recommended lubrication
• Elongation maximum of 3 percent
• Horizontal shafts
• Two 17-tooth sprockets

Question 19

The total length of a roller chain should be given in ??? because the ends must be connected with an outside and inside link.

Answer 19

multiples of twice the pitch (even number)

Question 20

distance between adjacent joint members

Answer 20

chain pitch

Question 21

the diameter of the pitch circle that passes through the centers of the link pins as the chain is
wrapped on the sprocket

Answer 21

pitch diameter

Question 22

the diameter of a circle tangent to the curve (called the seating curve) at the bottom of the
tooth gap

Answer 22

bottom diameter

Question 23

for a sprocket with an odd number of teeth, it is the distance from the bottom of the tooth gap
to that of the nearest opposite tooth gap

Answer 23

caliper diameter

Question 24

The caliper diameter is the ??? as the bottom diameter for a sprocket with an ??? number of teeth.

Answer 24

• same
• even

Question 25

it is the diameter over the tips of the teeth

Answer 25

outside diameter

Question 26

The following information shall be marked on the chains: ??? The following information shall be marked on the packaging: ???

Answer 26

1) Chain number designation. 2) Manufacturer’s name and/or its trademark 1) Chain number designation. 2) Manufacturer’s name, trademark, and address.

Question 27

Center distance between sprockets The center to center distance between sprockets, as a general rule, should not be ??? the diameter of the larger sprocket and not ??? the pitch nor ???. In certain cases, a center distance equivalent to ??? may be considered an approved maximum. The chain should extend around ??? of the pinion circumference, and this minimum amount of contact is obtained for all center distances provided the ratio is ???.

Answer 27

- less than 1.5 times - less than thirty times - more than 50 times the pitch - 80 pitches - at least 120 degrees - less than 3.5 to one

Question 28

If possible, the center distance should be adjustable in order to take care of the slack due to elongation from wear and this range of adjustments should be ???.

Answer 28

at least one and one-half pitches

Question 29

The following are the different designs or types of roller chain sprockets are shown by sectional views (Figure 5):

Answer 29

1) Type A - plain plate 2) Type B - has a hub on one side only 3) Type C - hub on both sides 4) Type D - detachable hub

Question 30

Materials For large sprockets, ??? is commonly used, especially in drives with large speed ratios. Smaller sprockets are usually made of ???. The use of ??? are for corrosion resistance while ??? are for special conditions.

Answer 30

- cast iron - steel - stainless steel or bronze - Formica, nylon or other suitable plastic materials

Question 31

Markings The following information shall be marked on the sprockets: ??? The following information shall be marked on the packaging: ???

Answer 31

1) Type of sprocket 2) Number of teeth of the sprocket 3) Corresponding chain number designation. 4) Manufacturer’s name and/or its trademark 1) Type of sprocket 2) Number of teeth of the sprocket 3) Corresponding chain number designation. 4) Manufacturer’s name, trademark, and address

Question 32

Oil is supplied periodically with brush or spout can, preferably once every eight hours of operation. Volume and frequency should be sufficient to prevent discoloration of lubricants in the chain joints.

Answer 32

Type I (Manual Lubrication)

Question 33

Oil drops are directed between the link plate edges from a drip lubricator. Volume and frequency should be sufficient to prevent discoloration of lubricant in the chain joints. Precaution must be taken against misdirection of the drops by windage.

Answer 33

Type II (Drip lubrication)

Question 34

With bath lubrication the lower strand of the chain runs through a sump of oil in the drive housing. The oil level should reach the pitch line of the chain at its lowest point while operating. With disc lubrication, the chain operates above the oil level. The disc picks up oil from the sump and deposits it into the chain, usually by means of a through. The diameter of the disc should be such as to produce rim speeds between ??? minimum and ??? maximum.

Answer 34

Type III (Bath or disc lubrication) - 183 m/min - 2438 m/min

Question 35

The lubricant is usually supplied by a circulating pump capable of supplying each chain drive with a continuous stream of oil. The oil should be applied inside the chain loop evenly across the chain width, and directed at the lower strand.

Answer 35

Type IV (Oil stream lubrication)