Official Answer
Answer
Multi-turn spiral retaining rings (often 2 or 3 turns) provide a $360^{\circ}$ retaining surface without the 'ears' or lugs found on stamped circlips. This leads to a more uniform distribution of the axial load around the circumference of the groove. In a multi-turn ring, the load is shared across the turns, although the turn closest to the load source bears the highest stress due to the axial gap between turns. The total thickness $T$ in the shear formula $P_s = \frac{D T \pi \tau}{K}$ is the sum of the individual turn thicknesses. This design eliminates the gap found in single-turn rings, which is vital in applications requiring uniform clamping or preventing the passage of small particles in a sealed assembly.
