Depending on the application, gearboxes that are shaft mounted can use a torque arm, (or reaction arm) to maintain gearbox positioning.
Torque Arm Gearbox
Other gearboxes to feature a torque arm include helical-bevels such as the Bonfiglioli A series and wormboxes such as the W series. Many times, the application will not be able to utilise the standard mounting positions of the gearbox housing, so the torque arm provides extra flexibility in this regard.
Not to be overlooked is another purpose of the torque arm on gearboxes: reducing any shock loads from the driven unit from working their way back through the gearbox, overloading gears and bearings in the process. Smoothing out these shock loads go someway to increase machine life.
All Torque Transmissions stocks and supports both the Bonfiglioli TA and Dodge TAII series of torque arm gearboxes, whilst the other arms for gearboxes need to be specified when ordering.