The washer preserves the surface of the clamped piece and generally reduces the stiffness of a screw. There are also complex-shaped washers that lock onto both the head and the surface of the screw. Renowned brands in this sector offer several types of washers, including support washers, elastic lock washers, and toothed lock washers. Among these, we can mention Grower washers, toothed washers, and absolute security washers.
The operating principle of toothed washers, also known as fan washers, is simple. Indeed, this washer increases the flexibility of the fastening system by anchoring into the support material. It proves to be very practical for fastenings vulnerable to collisions or that tend to loosen after several years of use due to vibrations of the fixed assembly, thanks to its aerated structure with teeth and relatively thin thickness. As its name suggests, the teeth embed into the material when the washer is compressed, which facilitates the increase in electrical contact or the adhesion of the fastening. Note that it is unnecessary to combine a flat washer and a fan washer on the same fastening, as this can cancel out the effects of the teeth. Some manufacturers gather a wide assortment of washers suitable for domestic and professional use into a single kit, including clamping washers and internal and external toothed washers.