Question

describe a synchro self shifting (SSS) clutch and how it operates

Answer 1

As the name indicates the shifting happens when the speed matches.

The SSS clutch is a freewheel-type, overrunning clutch which transmits torque through concentric surface-hardened gear teeth. 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.

When the speed if input shaft matches with the output , the pawls on one clutch element engage with ratchet teeth on the other to phase the teeth precisely for engagement. A few degrees of relative rotation causes the pawls to provide the small force to move the sliding As soon as the clutch input speed reduces relative to the clutch output speed, the clutch automatically disengages due to the reversal of torque on the helical splines.

The pawls are only required to overcome the small force that is necessary to accelerate the lightweight helical sliding component into partial tooth engagement. The pawls cannot transmit any driving torque because they move out of contact with the ratchet teeth by either relative axial or rotational movement before the clutch teeth
have shifted into full driving engagement. For this reason, the S.S.S. Clutch can be engaged at high rates of relative acceleration between the input and output shafts.