Door systems on rail vehicles have to meet high safety requirements and always operate reliably to protect people from danger. Schaltbau snap-action switches play a key role in sequence control for these systems. They serve various control functions in the doors:
No train is allowed to move while any door is still open. Snap-action switches (e.g. S826 series) are used as locked state monitoring switches to signal “door open” or “door closed”. In the event of a fault, the function has an additional safeguard with mechanical positive opening operation.
If the automatic door control fails in an emergency, it has to be possible to open the door manually. A snap-action switch (e.g. S847 series) serves as an emergency release switch that signals the “emergency door release activated” operating status.
An automatic door is taken out of normal operation if it no longer opens and closes properly. An out-of-service switch (e.g. S870 series) signals this operating status so that the door remains locked even when the central signal for opening the doors is given.
Why are Schaltbau microswitches used?
At each railway station or at every stop, numerous doors open for passengers. Then the doors have to reliably close again to ensure safe and smooth operation. Particularly on metropolitan services, this means a very large number of opening and closing cycles.
Due to their reliability, for many years Schaltbau microswitches have been successfully used as switching contacts in train door safety circuits under harsh operating conditions.
The snap-action switches have these features:
- Positive opening operation of the break contact (VDE approved)
- Suitable for safety-relevant applications
- Self-cleaning contacts
- High shock and vibration resistance
- IP67 (S847 W3)
- Ambient temperature: -40 °C … +85 °C
Microswitches in rail vehicle door control systems