Abstract: A drive coupling device comprises an outer drive shaft adapted to be driven for rotation by a gearbox output, an outer quill shaft coupled to the outer drive shaft and arranged to be driven for rotation thereby, an inner quill shaft arranged coaxially with the outer quill shaft and moveable, axially, between an engaged position in which a dog clutch arrangement is engaged to transmit drive between the outer quill shaft and the inner quill shaft, and a disengaged position in which the dog clutch arrangement is disengaged, a support rod, and support bearing means provided on the support rod and by which the outer quill shaft is supported for rotation relative to the support rod, wherein the outer quill shaft is further supported, when the dog clutch arrangement is engaged, by the inner quill shaft.