What is a Mechanical Interlock?

A mechanical interlock is a safety mechanism designed to control the sequence of operations between components or equipment using physical means. It is commonly used in industrial environments where safety is critical, such as electrical switchgear systems, machinery, and manufacturing processes.

How Mechanical Interlocks Work
 
Mechanical interlocks operate using physical force or mechanismssuch as pins, levers, bars, or sliding locks that prevent one action from occurring unless another condition is met. For example:

• In transfer switches, the interlock ensures that only one power source can be active at a time, preventing dangerous backfeeding between power supplies.
• In machine safety doors, the interlock ensures the machine cannot operate unless the door is completely closed, reducing the risk of injury from moving parts.

Benefits of Mechanical Interlocks

1. Enhanced safety Prevents unsafe operations or sequences that could cause harm.
2. Reduces human error Disallows actions that could result from mistakes or carelessness.
3. No electrical power needed Ideal for ensuring safety even during power outages.
4. Low maintenance Simple design with no electronic components, making it easier to maintain and repair.

Limitations of Mechanical Interlocks

• Not suitable for highly complex systems or those requiring flexible control logic.
• Requires precise design and installation to function correctly.
• Wear and mechanical jamming may impair performance over time.

Real-World Applications

• Electrical switchgear: Prevents simultaneous connection of multiple power sources.
• Industrial safety gates: Automatically stops machine operation when access doors are open.
• Heavy equipment control levers: Ensures machines cannot start unless all levers are in a safe position.