Roller chain

Roller chain or bush roller chain is the type of chain drive most commonly used for transmission of mechanical power on many kinds of domesticindustrial and agricultural machinery, including conveyorswire- and tube-drawing machinesprinting pressescarsmotorcycles, and bicycles. It consists of a series of short cylindrical rollers held together by side links. It is driven by a toothed wheel called a sprocket. It is a simple, reliable, and efficient means of power transmission.

Though Hans Renold is credited with inventing the roller chain in 1880, sketches by Leonardo da Vinci in the 16th century show a chain with a roller bearing

Construction of the chain

There are actually two types of links alternating in the bush roller chain. The first type is inner links, having two inner plates held together by two sleeves or bushings upon which rotate two rollers. Inner links alternate with the second type, the outer links, consisting of two outer plates held together by pins passing through the bushings of the inner links. The "bushingless" roller chain is similar in operation though not in construction; instead of separate bushings or sleeves holding the inner plates together, the plate has a tube stamped into it protruding from the hole which serves the same purpose. This has the advantage of removing one step in assembly of the chain.

The roller chain design reduces friction compared to simpler designs, resulting in higher efficiency and less wear. The original power transmission chain varieties lacked rollers and bushings, with both the inner and outer plates held by pins which directly contacted the sprocket teeth; however this configuration exhibited extremely rapid wear of both the sprocket teeth, and the plates where they pivoted on the pins. This problem was partially solved by the development of bushed chains, with the pins holding the outer plates passing through bushings or sleeves connecting the inner plates. This distributed the wear over a greater area; however the teeth of the sprockets still wore more rapidly than is desirable, from the sliding friction against the bushings. The addition of rollers surrounding the bushing sleeves of the chain and provided rolling contact with the teeth of the sprockets resulting in excellent resistance to wear of both sprockets and chain as well. There is even very low friction, as long as the chain is sufficiently lubricated. Continuous, clean, lubrication of roller chains is of primary importance for efficient operation as well as correct tensioning.

Use

·         Roller chains are used in low- to mid-speed drives at around 600 to 800 feet per minute; however, at higher speeds, around 2,000 to 3,000 feet per minuteV-belts are normally used due to wear and noise issues.

  • A bicycle chain is a form of roller chain. Bicycle chains may have a master link, or may require a chain tool for removal and installation. A similar but larger and thus stronger chain is used on most motorcycles although it is sometimes replaced by either a toothed belt or a shaft drive, which offer lower noise level and fewer maintenance requirements.
  • In older automobile engines from the United States and other countries, roller chains would traditionally drive the camshaft(s) off the crankshaft, generating less noise than a gear drive as used in very high performance engines, and offering more durability than the timing belt frequently used on more modern engines. Many modern automobile engines still use roller chains, which are more durable than timing belts.
  • Chains are also used in forklifts using hydraulic rams as a pulley to raise and lower the carriage; however, these chains are not considered roller chains, but are classified as lift or leaf chains.
  • Chainsaw cutting chains superficially resemble roller chains but are more closely related to leaf chains. They are driven by projecting drive links which also serve to locate the chain onto the bar.
  • A perhaps unusual use of a pair of motorcycle chains is in the Harrier Jump Jet, where a chain drive from an air motor is used to rotate the movable engine nozzles, allowing them to be pointed downwards for hovering flight, or to the rear for normal forward flight, a system known as Thrust vectoring.

 

Chain standards

Standards organizations (such as ANSI) maintain standards for design, dimensions, and interchangeability of transmission chains. For example, the following Table shows data from ANSI standard B29.1-2011 (Precision Power Transmission Roller Chains, Attachments, and Sprockets)[6] developed by the American Society of Mechanical Engineers (ASME).

A typical bicycle chain (for derailleur gears) uses narrow 1/2" pitch chain. The width of the chain is variable, and does not affect the load capacity. The more sprocket wheels at the back wheels confined space (historically 3-6, actually 7, 8, 9 or even 10 speeds) the narrower the chain. Hub gear or single speed bicycles use 1/2" x 1/8" chains.

Typically chains with parallel shaped links have an even number of links, with each narrow link followed by a broad one. Chains built up with a uniform type of link, narrow at one and broad at the other end, can be made with an uneven number of links, which can be an advantage to adapt to a special chainwheel-distance, on the other side such a chain tends to be not so strong.

ASME/ANSI B29.1-2011 Roller Chain Standard Sizes

Size

Pitch

Maximum Roller Diameter

Minimum Ultimate Tensile Strength

Measuring Load

25

0.250 in (6.35 mm)

0.130 in (3.30 mm)

780 lb (350 kg)

18 lb (8.2 kg)

35

0.375 in (9.53 mm)

0.200 in (5.08 mm)

1,760 lb (800 kg)

18 lb (8.2 kg)

41

0.500 in (12.70 mm)

0.306 in (7.77 mm)

1,500 lb (680 kg)

18 lb (8.2 kg)

40

0.500 in (12.70 mm)

0.312 in (7.92 mm)

3,125 lb (1,417 kg)

31 lb (14 kg)

50

0.625 in (15.88 mm)

0.400 in (10.16 mm)

4,880 lb (2,210 kg)

49 lb (22 kg)

60

0.750 in (19.05 mm)

0.469 in (11.91 mm)

7,030 lb (3,190 kg)

70 lb (32 kg)

80

1.000 in (25.40 mm)

0.625 in (15.88 mm)

12,500 lb (5,700 kg)

125 lb (57 kg)

100

1.250 in (31.75 mm)

0.750 in (19.05 mm)

19,531 lb (8,859 kg)

195 lb (88 kg)

120

1.500 in (38.10 mm)

0.875 in (22.23 mm)

28,125 lb (12,757 kg)

281 lb (127 kg)

140

1.750 in (44.45 mm)

1.000 in (25.40 mm)

38,280 lb (17,360 kg)

383 lb (174 kg)

160

2.000 in (50.80 mm)

1.125 in (28.58 mm)

50,000 lb (23,000 kg)

500 lb (230 kg)

180

2.250 in (57.15 mm)

1.460 in (37.08 mm)

63,280 lb (28,700 kg)

633 lb (287 kg)

200

2.500 in (63.50 mm)

1.562 in (39.67 mm)

78,175 lb (35,460 kg)

781 lb (354 kg)

240

3.000 in (76.20 mm)

1.875 in (47.63 mm)

112,500 lb (51,000 kg)

1,000 lb (450 kg)

 
Steel chain
Pitch ANSI ISO
3/8" 35-1 x 5M 06B-1 x 5M
1/2" 40-1 x 5M 08B-1 x 5M
5/8" 50-1 x 5M 10B-1 x 5M
3/4" 60-1 x 5M 12B-1 x 5M
1" 80-1 x 5M 16B-1 x 5M
1-1/4" 100-1 x 5M 20B-1 x 5M
3/8" 35-2 x 5M 06B-2 x 5M
1/2" 40-2 x 5M 08B-2 x 5M
5/8" 50-2 x 5M 10B-2 x 5M
3/4" 60-2 x 5M 12B-2 x 5M
1" 80-2 x 5M 16B-2 x 5M
1-1/4"" 100-2 x 5M 20B-2 x 5M
Hollow pin chain
Other sizes
40HP-1 x 5M
50HP-1 x 5M
60HP-1 x 5M
80HP-1 x 5M