Retainers include products, which, although they cannot initially prevent self-unscrewing, prevent complete unscrewing after a more or less large pretension loss, thus stopping the connection from falling apart.
This category includes, for example, nuts with:
- Polyamide inner rings (lock nuts with a plastic ring)
- All-metal lock nuts
Also included are thread inserts and screws with a clamping piece according to DIN 267, part 28.
Retainers also include thread-rolling screws:
- Retainer due to the special thread
- Self-tapping screws form their mating thread themselves
- The positive locking between the bolt thread and the nut thread ensures a tight fit
- Fibre alignments are not interrupted but rather reshaped and strain-hardened