PAES 303:2000 Engineering Materials –Roller Chains and Sprockets for Agricultural Machines Specifications and Applications

chain pitch

distance between adjacent joint members

pitch diameter

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

bottom diameter

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

caliper diameter

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. NOTE: this is the same as the bottom diameter for a sprocket with an even number of teeth.

outside diameter

it is the diameter over the tips of the teeth

Type I (Manual Lubrication)

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.

Type II (Drip lubrication)

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.

Type III (Bath or disc lubrication)

With this type 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.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 183 m/min minimum and 2438 m/min maximum.

Type IV (Oil stream lubrication)

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.