Functional Principle
The original SCHNORR® safety washers are in the form of a disc spring but with a trapezoidal cross-section and serrations on both sides. The outer diameter is matched to the head diameter of the pan head and socket head cap screws.
SCHNORR® safety washers are available in two versions: the standard safety washer type “S” is available for screws of sizes M1.6 to M36 and of the property classes up to 8.8. For screws of property classes 8.8 and 10.9, higher pretension forces might be necessary. These are covered by our reinforced washers type “VS”.
Due to the conical form, optimal traction is achieved at highest positive locking due to the helical gearing.
Vibration test according to DIN 65151
Extensive test series carried out at the “Staatliche Materialprüfungsanstalt” (public material research laboratory) in Darmstadt prove that the original SCHNORR® safety washer manufactured using the a patented manufacturing method brings about a clear improvement of the safety properties.
Conclusion
- Connections secured using a SCHNORR® safety washer maintains the pretension force also after 1,500 cycles.
- An unsecured screw connection has lost its pretension already after less than 500 cycles.