Trapped key interlock system

Using a mechanical interlock system is a tested method for mechanically safeguarding machines and hazardous processes. The system works by trapping and releasing coded keys in a predetermined sequence.

The Fortress Interlocks trapped key system is the only interlock system on the market that is TüV certified for use in PLe according to EN / ISO 13849 and SIL 3 according to EN 62061 machine safety applications.

A trapped key interlock system consists of a (lockable) key switch or bolt lock and one or more locks for monitoring safety devices, such as doors, hatches, flaps or shut-off valves.


Our trapped key interlocks have the following unique features:

• No cabling required to connect doors and hatches.
• Very easy to install retro-fit on existing installations.
• Easily increase the safety level of your machine.
• TüV certified to PLe (EN / ISO 13849) and SIL 3 (EN 62061).
• Limited intervention on the controls.
• Extremely robust and suitable for the harshest industrial environments.
• Very good resistance to vibrations.
• Versions for machines with and without run-down time available.
• Suitable for use in explosive environments (ATEX).
• Resistant to extreme temperatures.
• Stainless steel versions for corrosive environments, outdoor use and the food industry.
• 200,000 unique key encodings.
• Ideal for wash-down, CIP and damp environments.