Hand Torque Multipliers incorporate an ‘Epicyclic’ or ‘Planetary’ gear train with one or more stages. Each stage of gearing increases the torque applied by a factor of 5, allowing to offer torque multipliers in ratios of 5:1, 25:1 and 125:1. In the planetary gear system, the torque is applied to the input gear or ‘Sun’ gear. Three or four planet gears, with teeth engaged in the sun gear, rotate. The outside casing of the torque multiplier, or ‘Annulus’ is also engaged with the planet gear teeth, and would normally rotate in the opposite direction from the sun gear. A reaction arm prevents the annulus from rotating, and this causes the planet gears to orbit around the sun gear. The planet gears are held between input and output plates which also hold the output square drive. Therefore as the planetary gears orbit around the sun gear, the output plate and the square drive turn. To be noted: Without the reaction arm to keep the annulus stationary, the output square will not apply torque.
It is a simple gear box, works on the principle of ‘Epicyclic Gearing’. The given load at the input gets multiplied as per the multiplication factor and transmitted at the output, thereby achieving a greater load with a minimum effort.