Roller

The concept of the roller was evolved when man discovered that logs could be used for transportation. Since then a roller in its basic avatar has remained round / cylindrical in shape and has different uses corresponding to it's size. Rollers also played a key role in the evolution of the printing press. Even in contemporary printers, one of the key components is the inbuilt roller, known as the drum. The Road roller, an engineering vehicle, has a gigantic metallic roller attached in the front. These road rollers are used to compact soil, gravel, concrete or asphalt during construction of roads. It is an extremely helpful tool for making roads even and long lasting. A road roller is also called the steam roller.

A roller can also refer to an agricultural tool that is used for flattening land or breaking up large clumps of dirt. These rollers are often pulled by tractors. Roller bearings help in carrying a load that is placed around an element or between two separate pieces. Roller bearings are often used in drawers since they allow the drawer to be opened or shut smoothly. A roller can also mean a cylindrical machine component. A police car is colloquially addressed as a roller. Roller technology is also used in roller ball pens. These pens are capable of smooth writing with water-based ink.