FRICTION ITEM Russian patent published in 2011 - IPC F16D66/02 F16D69/02 F16D65/04 

FIELD: machine building.

SUBSTANCE: friction item has working surface, pressure surface, and side surfaces. On side (or one of sides) surfaces of the item there is set a wear indicator made in form of a lug or recess. The wear indicator is made so, that corresponding lines of cross section of side surfaces of the item and surface of the indicator are made with not smooth transition (transition with a curve) along arc with radius from 0.2 mm to 1.5 mm for each plane of cross-section of the item orthogonal to pressure and side surfaces of the item.

EFFECT: simplified design of item and its practical manufacture in existent serial production.