Belleville Washers

Hero Metal carries Belleville washer in imperial as well as metric sizes. Belleville washers also called conical spring washers are manufactured and are designed specifically for Heavy Duty Bolted section such as Bus Bars, Transformers, Rectifiers, Heat Exchangers, Transmission, etc. These washers are intended to counteract the effect of setting which results in bolt/nut assemblies working loose. They do not effectively prevent loosening of the assembly under varying radial load and are designed for use with short bolts predominantly subject to thrust.
Belleville washer consists of primarily of a convex disc supported at the outer periphery by one force and an opposing force on the center of the disc. These are used singly, or in stacks, to achieve a desired load and travel.
The advantage of a Belleville washer is that it generates high force in a very short spring length and with minimal movement when compressed. It allow thermal expansion and vibration, or to maintain distance between machine parts.
Belleville washers are typically used as springs, or to apply a pre-load of flexible quality to a bolted joint or bearing. They may also be used as locking devices, but only in applications with low dynamic loads, such as down-tube shifters for bicycles. Belleville washers are seen on Formula One cars, as they provide extremely detailed tuning ability.
Belleville washers, when used on the mounting bolts, are also useful as an indicator of swelling or shrinkage of wooden propellers on aircraft (typically experimental aircraft). By torquing their associated bolts to provide a specific gap between sets of washers placed with "high ends" facing each other, a change in relative moisture content in the propeller wood will result in a change of the gaps which is often great enough to be detected visually.
As propeller balance depends on the weight of blades being equal, a radical difference in Belleville washer gaps may indicate a difference in moisture content.