TFC's familiar and popular Smalley Spirolox Retaining Rings can also be manufactured with a unique self-locking feature that make them ideal for applications where high rotational speeds are involved or, where the effects of vibration, rapid acceleration or impact loading is problematic.

Self-locking rings provide a mechanical interference via a small tab on the ring that locks into a corresponding slot in the opposite turn and prevents the ring from expanding out of the groove as a result of centrifugal forces at high rotational speeds.


The location of the locking mechanism can be dictated by the application requirements. Internal and external locks are easier to install (especially when small diameters or heavy cross-section material is involved) and allow for a simple visual confirmation of proper installation.

Where tamper-proof applications are involved, 'centreline' locks are typically used and once the ring is removed from an application, the tab is broken and a new ring must be installed. This type of locking feature is also less likely to interfere with mating components within the assembly.

Aerospace and Automotive industries often use self-locking rings because the rotational capacity typically meets or exceeds the application requirements and can be found in transmission and clutch assemblies.

For more information, contact TFC's Technical Department on +44 (0)1435 866011 or via

sales@tfc.eu.com