Hoopster retaining ring for use in thin-wall components

Paul Boughton
TFC Europe is expanding its Smalley Retaining Ring range with the arrival of the Hoopster. The Hoopster is suitable for applications where the depth of the groove is critical, such as in thin-walled cylinders, since it only requires a shallow groove. Instead of edge-coiling the material, it is coiled on the flat to produce a ring that has an extremely low profile.

Unlike when using a conventional retaining ring or circlip, the retained component in a Hoopster Retaining Ring assembly may have a corner break. Thrust load is not sacrificed when the retained component has a broken corner because the moment arm is negligible. The shallow groove associated with the Hoopster, in combination with the groove material, are the controlling factors in determining thrust capacity. The Hoopster does not twist when loaded, so pure thrust load based on shear strength of the material maximises the Hoopster's load carrying capacity.

Groove deformation is by far the most common design limitation of most retaining rings. Unlike a conventional retaining ring or snap ring that fails by deforming or twisting, the Hoopster Retaining Ring shows superior strength from its low profile and mechanical advantage over traditional retaining rings under load. With a Hoopster there is no moment arm that twists the ring, causing premature failure as can be experienced with a conventional retaining ring.

The shallow groove specification of a Hoopster makes the groove wall a critical specification to ensure the correct functioning of the ring. To obtain maximum load capacity from a Hoopster Retaining Ring it is essential to have sharp corners on the groove; the maximum radius on the groove bottom should be no greater than 10 per cent of the rings radius wall. Maintaining a sharp corner on the top of the groove is just as critical.

Hoopster retaining rings are suitable for medium or light loads and are available as standard in carbon steel and 302 stainless steel in a variety of sizes, plus bespoke sizes can be produced with no extra tooling charges.

For more information, visit www.tfc.eu.com

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