Dished washer_ Disc springs, also known as Belleville spring washers, were invented by the French man Belleville. The dished washer (DIN6796 DIN2093 DIN2092 DIN6796) (HDS series) is a lock washer designed for bolt and screw connections. It is designed and manufactured according to DIN 6796 and is used for the connection of medium or high strength bolts and screws. The high support load and elastic recovery make the HDS series very effective. The bolt tension can withstand relaxation caused by wear, creep, relaxation, thermal expansion, contraction of vulnerable parts, or compression of sealing components. The HDS series has increased the elastic effect of screws several times, and it can effectively replace ordinary spring washers, but is not suitable for use as a combination of lock washers and flat washers. Due to the fact that the HDS series can be paired or stacked with disc springs. The combination of pairing methods can increase the deformation of the disc spring assembly, while the combination of stacking methods can increase the spring force of the disc spring assembly. The ideal installation method is to flatten as much as possible, and the closer it is to the flattening state, the faster the tension torque increases. No torque wrench is required, and appropriate bolt tension can be obtained.