Self-locking bolt has ribs on underside of its head and locking washer attached to its shaft which has grooves on its top and ribs on its underside, which is also coated with friction-increasing material

摘要

The bolt has a locking washer attached to its shaft. The underside (6) of the bolt head (2) has ribs (7). These cooperate with grooves on the top of the washer. This also has ribs on its underside and is coated with friction-increasing material.