Torque multiplier

Torque multipliers typically employ an epicyclic gear train having one or more stages.

Without the reaction arm to prevent rotation of the outer casing, the output shaft cannot apply torque.

There are many instances where screws, bolts and other fasteners are secured so tightly that using a typical lug wrench with a cheater bar is not sufficient to loosen them.

These include automotive repair, product assembly, construction projects, heavy equipment maintenance and other instances where high torque output is needed.

They are also used as a safer alternative to a cheater bar as lever length and operator effort are both reduced.

Epicyclic gearing can be used in a torque multiplier. The sun gear (yellow) is driven by an input torque. The planet gear carrier (green) provides the output torque, while the ring gear (red) is fixed. Note the red marks both before and after the input drive (yellow) is rotated 170° clockwise.