Patent ID: 11920625
Assignee: GROWERMETAL S.P.A.
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F | IPC F

Claim 0:
1. Washer having a having central hole, a bolt under head engaging surface and a bearing engaging surface with a serration on both surfaces, wherein
the serration on the bolt under head engaging surface comprises a saw tooth structure,
the edges of the saw tooth structure in top view of the bolt under head engaging surface of the washer have a boomerang shape with the tip of the boomerangs pointing into the untightening direction of the washer,
the serration on the bearing engaging surface comprises a plurality of teeth which in top view of the bearing engaging surface run in the direction from the inner to the outer circumference of the bearing engaging surface and which are inclined with regard to radially extending straight lines originating from the washer center so that the ends of the teeth close to the inner circumference of the washer point into the tightening direction, and
the top sections of both the teeth and the saw teeth in cross-sectional view of the serrations are rounded.