The term load washers refers to a specialty version of a disc spring or Belleville washer used to improve security of a bolted connection. They prevent a loosening of the connection by e.g. setting losses in that their own spring load can maintain the initial load of the connection. This makes them very suitable for mostly axially loaded short screws. They are not effective against coming loose due to changing cross loading.
These SCHNORR® load washers have been specially designed for high-strength bolts up to a strength class 8.8 to 10.9 acc. to DIN ISO 898 part 1. This represents the most powerful form of safety washer in the form of a disc spring.
The loads of these washers when pressed flat reach 70 to 90 % of the corresponding bolts of the strength class 8.8.
These load washers conform to DIN 6796 and are designed for high demands on the protection of bolt joints. As a highly progressive load increase occurs at the end of the spring deflection when the washer is flattened the load has been indicated as double the calculated value. Tests have shown that these values are comparable with the measured values.
For the protection of bolted joints only that load is available which remains after the washer has initially set. The table in SCHNORR's brochure indicates the respective minimum height after the initial loading of the washer. Thus the maximum loss of height due to setting is limited.