roller

A roller is a cylindrical element that rotates around an axis, commonly used to support, guide, or transmit motion and materials. Rollers come in many sizes and designs and may be integrated into machines, vehicles, or consumer tools.

In machinery, rollers often serve as rolling elements in bearings or as load-bearing wheels. Roller bearings use cylindrical or spherical rollers to reduce friction and carry radial loads. Common forms include cylindrical, needle, and spherical rollers. In chain drives, rollers on each link engage with sprockets to transmit force.

In material handling and transportation, rollers appear in conveyor systems, idlers, and roller chains. They guide and support moving products with minimal friction.

In households and kitchens, a roller can be a paint roller or a wallpaper roller for applying finishes. A rolling pin is a kitchen implement used to flatten dough by rolling it across a surface.