Safety Interlock Switches
In safety switches, positively driven contacts are used for the switching elements. These switching contacts are always reliably separated. The connection is opened by the actuating force even if contacts become welded together. It is a common feature of all switching elements that at least one switching element is designed as a positively driven contact. Often two positively driven contacts are employed to increase safety using the principle of duplicated design (redundancy). This dual-channel design ensures that the failure of one channel or a fault in the control circuit can be detected and the interlocking function can still be provided with the aid of the second channel.
Euchner Type 1 safety switches have an integrated actuator and safety contacts that are closed when the actuator is not activated. Type 2 safety switches use a separate actuator and have safety contacts that are closed when the actuator is inserted into the switch. Type 2 interlock safety switches are also available with solenoid locking/unlocking capability.
Non-Contact Safety Switches
Non-contact safety switches are interlocking devices that are designed to protect people and machines. Compared with electromechanical safety switches, non-contact switches are used if a high level of protection against tampering much be achieved, extremely hygienic environmental conditions are required (e.g. in the food industry), a precise door guide is not possible, machine doors are subjected to heavy vibration, or if a high safety category is stipulated during the risk analysis.
