The disc spring, also known as the Belleville spring washer, was invented by Belleville, France. Its conical disc shape can be used either individually or in series or in parallel. It bears static or dynamic loads acting along the axial direction at the upper and lower edges. It is compressed and deformed until it is flattened and stored as live loads in the form of energy. When necessary, it is automatically converted into additional compression load needed for sealing, so as to reduce the continuing requirement of tightening in the use of washers and fillers.

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