Out of the numerous types of a profiled wheel, sprocket is one. It has teeth branching outwards which connect with the chain or some other indented material. The literal meaning of sprocket is any circular body over which a chain passes. Contrary to the popular misconception, a sprocket is not a gear and should not be characterized as one.
Neither it is a pulley or a type thereof. Unlike gears, they never mesh directly with each other. And unlike pulleys, sprocket do not have a smooth near-frictionless surface but rather have teeth coming out of the center and spreading outwards.
Most popular applications of sprockets include bicycles, tricycles, motorcycles, and any other equipment tasked with transmitting rotary motion. Gears cannot be used for the same tasks that sprockets perform due to their inability to keep a body in a linear motion.
In applications that do not condone slippage, sprockets are widely used. Due to their versatility, sprockets can operate at high speeds and in most cases, if installed and maintained, are virtually noiseless.
A duplex is a type of a worm gear that has two differently manufactured sides with dissimilar modules as well as diameter quotients. Thus, it is possible to get varied lead angles on each of the tooth profiles. It allows for tooth thickness to keep increasing over the entire length of the worm. At the same time, the distance between the threads decreases continually. Through such a system, it is possible and even convenient to keep the backlash in check.
For the bicycles and cycles of most other types, it is possible to maneuver the gear ratio belong to the chain drive. It can be accomplished by the altering the sprocket's diameter on both sides of a chain. Derailleur gears follow this principal when they operate although there are slight variations.