Which of the following options correctly identifies the RGB as a single-stage, foot-mounted, parallel shaft, vertically offset gearbox with double helical gears?

• A. Power Transmission Gearbox
• B. Planetary Gear Unit (PGU)
• C. Reduction Gearbox (RGB)
• D. Torque Converter (TC)

Answer: (C)

Recognize how gearboxes are classified by mounting, shaft arrangement, offset, and gear type. The features described—single-stage reduction, a base or foot-mounted frame, input and output shafts running parallel, a vertical offset in the gear train, and the use of double helical gears—point to a Reduction Gearbox.

Single-stage means the reduction happens in one gear mesh rather than through multiple stages, which keeps the design compact. Foot-mounted indicates the unit is designed to bolt to a foundation. Parallel shafts mean the input and output shafts lie in the same plane and run side by side, not at an angle or through a planetary arrangement. Vertically offset describes how the gears are arranged within the housing to achieve the required center distance while maintaining the parallel-shaft configuration. Double helical gears provide higher load capacity and smoother, quieter operation by canceling out axial thrust, which is desirable for a robust single-stage reduction.

Other options don’t fit this arrangement: a planetary gear unit uses sun and planet gears with a carrier and is not a simple parallel-shaft, single-stage layout; a torque converter is a fluid coupling rather than a gear reduction with gears; and a generic power transmission gearbox is too broad to specify the described configuration.