How It Works
When the input shaft and sliding component reach the same speed as the
output, they rotate until a ratchet tooth contacts the tip of a pawl
on the output clutch ring this prevents further rotation of the sliding
component relative to the output clutch ring (position shown).
As the sliding component moves along the input shaft, the pawl passes
out of contact with the ratchet tooth, allowing the clutch teeth to come
into flank contact and continue the engaging travel. Note that the only
load on the pawl is that required to shift the lightweight sliding component
along the helical splines.
When a nut is screwed against the head of a bolt, no external thrust is produced. Similarly when the sliding component of an SSS Clutch reaches its end stop and the clutch is transmitting driving torque, no external thrust loads are produced by the helical splines.
If the speed of the input shaft is reduced relative to the output shaft, the torque on the helical splines will reverse. This causes the sliding component to return to the disengaged position and the clutch will overrun.
The SSS Clutch can continuously operate engaged or overrunning at maximum speed without wear occurring.
At high overrunning speeds, pawl ratcheting is prevented by a combination of centrifugal and hydrobodynamic effects acting on the pawls.
Where necessary, an oil dashpot is incorporated in the end stop to cushion the clutch engagement.