ANSI Roller Chain Sprockets

ANSI roller chain sprockets engage chains in many different power transmission and conveyor systems. Chain drives are often used as economic, reliable drive systems for long running, continuous drive applications with limited shock and torque loads. English sprockets are classified according to ANSI number designations. Sprockets engage chains in many different power transmission and conveyor systems. Chain drives are often used as economic, reliable drive systems for long running, continuous drive applications with limited shock and torque loads.

Pitch is the distance between adjacent tooth centers. Numbers shown are ANSI designations. ANSI roller chain sprockets are categorized according to ANSI B 29.1M. The number can be used to identify pitch in the following way: the first digits identify the pitch in 1/8" increments, and the last digit is 0 for standard proportions, 1 for lightweight chain, and 5 for rollerless bushed chain. A #41 sprocket is therefore for 1/2"-pitch lightweight chain, a #120 sprocket is for 1-1/2" pitch chain, etc.  Important dimensions to consider when searching for ANSI roller chain sprockets include number of teeth, bore diameter, hub diameter, outside diameter, length through bore, and weight.  Number of teeth for a specified pitch will determine sprocket size and drive ratio.  The bore diameter is the diameter of center bore for shaft mounting.  The hub diameter is the outside diameter of desired hub.  The outside diameter is the diameter of the sprocket including teeth. It is primarily of concern if clearance is an issue.  The length through bore is the total width of the sprocket, including hub(s).

Material selection is dependent on factors such as required power transmission and speed, environmental factors such as temperature and exposure to corrosive elements, and other factors such as noise generation. Consult with a sprocket manufacturer on a specific application to optimize material selection. Common material choices for ANSI roller chain sprockets include all plastic, plastic teeth with a metal insert, standard steel, hardened steel, and stainless steel. The sprocket style can be single, double, triple, quadruple, and quintuple or higher.  A single style sprocket has one sprocket on one hub. A double style sprocket has two sprockets on one hub, and so on. Some sprockets are idler sprockets. Idler sprockets rotate freely while taking up slack and providing tension to a chain drive system. They are used as tensioners and occasionally to provide chain clearance around a machine component. The idler style can be bronze bushing or ball bearing.

The hub style on ANSI roller chain sprockets can be Type A (hubless), Type B (hub on one side), Type C (hub on both sides), and Type D (detachable bolt-on hub).  Specialty hubs include tapered bushing, and shear pin hub.  Tapered bushings are tightened down onto the shaft like a collet to minimize shaft marring.  Shear pin provides protection against drive system jamming or overload. Torque is carried by shear pin, which is necked to shear when safe load is exceeded.  Shaft mounting choices for ANSI roller chain sprockets include set screws, keyway, and simple bore. An important environmental parameter to consider is the operating temperature.

• ANSI Pitch
  ANSI Pitch is the number designations for roller chain pitch that are governed by the American National Standards Institute (ANSI). English roller chain and sprockets are categorized according to ANSI...
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