English to Portuguese Tech/Engineering Engineering: Industrial Perfuratriz- Mineração

Hydraulically-actuated locking collars slide over the back brace joints to secure the extended braces.
When the mast is lowered, the locking collars are retracted and the back braces automatically fold.

Remove the lock wire and two cap screws, two lock washers, and two nuts that secure the band around the outside of the locking collar cylinders.

achei anel de retenção, colar de travamento, anel de travamento...
Pode ser qualquer um desses?