
OVERDRIVE GEARS 285
bushed at its forward end to furnish a spigot bearing
support for the end of the gearbox mainshaft.
An addition to the basic gearset is a one-way roller
clutch that acts between the mainshaft of the gearbox
and the tailshaft of the overdrive unit. The inner mem-
ber of the roller clutch is splined to the end of the
mainshaft and provides the cam track, while the outer
member has a plain track and is retained within the hub
of the annulus gear.
The double-cone clutch is actuated via a thrust ring
with ball race, and offers the advantages of high torque
capacity for a moderate clamping load and minimum
drag when disengaged