The drive chain application:
The double-row roller chain  is one of the major elements in the actuating unit. Chain driving are applied in equipment in drives of machines to movement transfer from a master shaft on one or several conducted shaft.

Structure of roller chain:
The chain consists of the roller which is pressed in external plates of a chain and forms with them a single whole. On the roller the plug is freely put pressed in internal plates. On the plug the roller is established freely. In case of a chain contact it gives a rotary motion to an asterisk by means of friction of swing.