1 OVERRUNNING CLUTCH
The freewheel disengages automatically when the driven member rotates faster than the driving member.
2 INDEXING CLUTCH
The freewheel allows the conversion of
reciprocating motion into a discontinuous rotational movement.
3 BACKSTOP
The freewheel allows rotation in one direction only. It overruns continuously during operation. The freewheel prevents reverse rotation if the drive is disconnected.
Overrunning clutches are directional couplings, which means they are engaged and disengaged automatically, depending on the relative direction of rotation of the driving and driven sides. Practical applications of this principle:
1 OVERRUNNING CLUTCH
for multiple-machine drives or to separate the inertia of masses of a driven machine from the driving machine after it has been switched off.
2 INDEXING CLUTCH
which turns a shaft step by step, thus achieving indexed material feed or a variable speed.
3 BACKSTOP
to prevent a machine shaft turning backwards. In this case the overrunning clutch acts as a brake.