Window Roller is a bearing with plastic coated roller can be used for doors and windows.

Pulley bearings are deformation lever, which belongs to simple machinery of lever type and has a wide range of uses.
It not only saves labor, but also changes the direction of force.

The pulley whose central axis moves with the weight is called the movable pulley. It is a deformed unequal arm lever (labor-saving lever), which can save half the force, but it takes twice the distance (the movable pulley rises by N meters, the free end of the string rises by 2n meters, n ≥ 0), and the direction of the force cannot be changed. No matter where the force direction of the fixed pulley rope is, the force used to lift the heavy object is equal (the rope weight and the friction between the rope and the pulley are not counted) (the power arm and the resistance arm are equal and equal to the radius of the pulley);

When the force direction of the moving pulley string is vertical and upward, it is the most labor-saving.

ZZ BEARINGS can produce custom Sliding window nylon roller with axle pin for window.