epicyclic

adj

1. (not-comparable)Of or relating to epicycles.
2. (not-comparable)Of a gearbox, having two gears mounted so that the center of one gear revolves around the center of the other.

   “Power is derived from a British United Traction Limited "A"-type 150-h.p. six-cylinder horizontal diesel engine; this drives through a fluid flywheel, and thence through a free wheel unit to a four-speed epicyclic gearbox.”

   “The gearbox is of the self-changing compound epicyclic SE.4 type, with Sinclair fluid coupling, having a maximum torque of 750 lb./ft.”