A Belleville washer is a type of non-flat washer and has a slight conical shape which gives the washer a spring characteristic. They are often used to solve vibration, thermal expansion, relaxation and bolt creep problems. Their conical configuration enables them to support high loads with relatively small deflections and solid heights compared to helical springs. They are severely travel limited compared to a conventional coil spring when free length is not an issue. Belleville washers may also be used as locking devices, but only in applications with low dynamic loads.
Belleville washers are useful for adjustments because different thicknesses can be swapped in and out and they can be configured differently to achieve essentially infinite tunability of spring rate while only filling up a small part of the technician's tool box. They are ideal in situations where a heavy spring force is required with minimal free length and compression before reaching solid height. Some of the advantages of Belleville washers include: