A chain drives consists of two gears, called sprockets, on which an infinite chain is put on. Engagement occurs between the teeth of the chain sprockets. The chain, unlike the belt, does not slip and can be used in gears with a small distance between the shafts, as well as in gears with a significant gear ratio. A significant advantage of chain transmission is also a lower load on the shafts and bearings compared to belt transmission of the same power.
This is explained by the fact that when the chain transmission tension is experienced only one branch of the chain-the leading, driven weakens, and therefore reduces the pressure on the shafts. In addition, the chain transmission does not require such a chain tension, as on the belt, since the transfer of forces is not carried out as a result of the action of friction forces, and the teeth of the chain sprockets, which operate at high speeds, reaching up to 35 meters per second and the gear ratio i=15. The efficiency of chain drives in some cases is 0.98.
Used in mechanical engineering chains by the nature of the work performed are divided into drive, cargo and traction.
Drive chains in most cases carry out the transfer of movement from energy sources to the variable body of the machine. They work both at low and high speeds, at various inter-center distances of the axes of the stars.
Cargo chains are used for suspension, lifting and moving cargo at a speed of no more than 0.25-0.5 meters per second and work on blocks, winches, hoists, lifting installations, hydraulic structures and other mechanisms of periodic use.
Traction chains are used for transporting and moving goods at any angle by means of load-bearing working mechanisms attached or suspended from the chains. They are used as traction or transporting in conveyors, lifts, escalators, elevators and other chain devices. The speed of the chain of this group usually does not exceed 2 meters per second.
By design features and types of chains are divided into bushing, roller long-link, link, multi-row, roller with curved plates, toothed with rolling joints, roller collapsible, bushing-roller.