✅ Designed to operate in the most demanding environments
✅ Single Fortress interlock does not require additional safety components added to meet PLe
✅ Non-stainless and stainless steel construction of all system components
✅ Can be controlled in sequence to remove integration requirements between different technologies
✅ Special purpose units can be designed to provide solutions for specific needs
✅ Large range of switch variants for electrical isolation, bolt modules and valve interlocks for pneumatic and hydraulic isolation
✅ Controls operations in sequence to reduce the need for programmable logic
✅ Eliminates electrical wiring without reducing safety performance
✅ Reduces cost of cabling and installation
✅ Rigorously tested to guarantee performance under the most heavy duty conditions
✅ Suitable for applications up to SIL3 Cat.4 PLe
✅ 3rd party approved for applications requiring high reliability
Robust Construction
✅ Designed to operate in the most demanding environments
✅ Single Fortress interlock does not require additional safety components added to meet PLe
✅ Non-stainless and stainless steel construction of all system components
Multiple Energy Sources
✅ Can be controlled in sequence to remove integration requirements between different technologies
✅ Special purpose units can be designed to provide solutions for specific needs
✅ Large range of switch variants for electrical isolation, bolt modules and valve interlocks for pneumatic and hydraulic isolation
No Programmable Logic
✅ Controls operations in sequence to reduce the need for programmable logic
✅ Eliminates electrical wiring without reducing safety performance
✅ Reduces cost of cabling and installation
Pre-validated so you don't have to
✅ Rigorously tested to guarantee performance under the most heavy duty conditions
✅ Suitable for applications up to SIL3 Cat.4 PLe
✅ 3rd party approved for applications requiring high reliability
Our database is part of the service
Select from the Mechanical Trapped Key Range
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Fortress Product Feature - mGard Trapped Key Range
Trapped key interlocking is versatile, robust and can be used to solve complex safety sequences, particularly where multiple energy sources exist. Electrical, pneumatic, hydraulic, and kinetic energy sources can all be interlocked using mGard products, and typically at a fraction of the cost of alternative solutions.
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What is Trapped Key Interlocking?
📜 Fortress mGard products are designed, tested and TUV approved for use in Category 4/PLe safe control systems. A single Fortress interlock does not require additional safety components added to meet PLe.
Watch our Product Videos to Learn More
Changing the handing on mechanical products is easy
Watch our short video showing how simple this can be.
🔎 Explore the Range
Control Interlocking
Solenoid Controlled Trapped Key Switches to Enforce Run-Down
Mechanical Timer and Voltage Sensing Solenoid Controlled Solutions
Power Interlocking
Intermediate Transfer
Access Control
Keys and Accessories
Contact us and we can help define your trapped key interlock system.
At Fortress we will always look to assist with project delivery and efficiency by supporting on the design of trapped key interlock systems. Our team can be on hand to survey equipment on site, interpret system drawings or discuss concepts early on in project design.
The advantage of trapped key systems is that any number of power sources can be interlocked into any number of access points. Determining part numbers and a bill of materials may initially appear complex but a Fortress representative can assist with this and provide engineering drawings of each component.
Using end user information and project documentation we can coordinate across multiple integrators and equipment suppliers.
All downloadable assets
To have access to the mGard technical information, please login to
EN - mGard Brochure
Actuators Operating Instructions
BM(S) Operating Instructions
DM(S) Operating Instructions
XM & XMS Operating Instructions
Solenoid Switches Operating Instructions
Mini Solenoid Switches Operating Instructions
Accessories - mGard - Operating Instructions
Key Operated Switch (S) - mGard - Operating Instructions
- Select from our range of high-coded compact yet robust interlocks here.
- Use our Datasheets / drawing generators to create technical files, datasheets, and CAD for your selected product.
- Convert your unique ITM number into a Fortress part number using our Reference tool
- Calculate the performance level of your unique safety system using our SISTEMA library
- Click here for more Fortress Product tools
Build Your System
Contact us and we can help define your trapped key interlock system.
At Fortress we will always look to assist with project delivery and efficiency by supporting on the design of trapped key interlock systems. Our team can be on hand to survey equipment on site, interpret system drawings or discuss concepts early on in project design.
The advantage of trapped key systems is that any number of power sources can be interlocked into any number of access points. Determining part numbers and a bill of materials may initially appear complex but a Fortress representative can assist with this and provide engineering drawings of each component.
Using end user information and project documentation we can coordinate across multiple integrators and equipment suppliers.
Downloads & Technical Info
EN - mGard Brochure
Actuators Operating Instructions
BM(S) Operating Instructions
DM(S) Operating Instructions
XM & XMS Operating Instructions
Solenoid Switches Operating Instructions
Mini Solenoid Switches Operating Instructions
Accessories - mGard - Operating Instructions
Key Operated Switch (S) - mGard - Operating Instructions
In Use
Drawings & 3D CAD Files
- Select from our range of high-coded compact yet robust interlocks here.
- Use our Datasheets / drawing generators to create technical files, datasheets, and CAD for your selected product.
- Convert your unique ITM number into a Fortress part number using our Reference tool
- Calculate the performance level of your unique safety system using our SISTEMA library
- Click here for more Fortress Product tools
