SafetyInterlock

SafetyInterlock refers to a safety mechanism or system that prevents a machine or process from starting or continuing operation until a predefined safe condition is met. They are used to protect workers by ensuring that access doors, gates, or safeguarding devices are in a safe state before motion or hazardous operations can occur.

Interlocks can be mechanical, electrical/electronic, or a combination. Mechanical interlocks rely on physical engagement; electrical interlocks use sensors and circuits to monitor guard status; electronic interlocks can be integrated with safety controllers or safety PLCs to enforce safe operating sequences. They are designed to ensure that hazardous conditions cannot arise while guards are open or unsafe states exist.

Common applications include guarding on presses and conveyors, machine doors on CNC equipment, lifts, and robot work cells. When a guard is opened or sensors detect an unsafe condition, the interlock changes to a safe state, such as stopping the machine and preventing restart until the issue is resolved. Interlocks should be part of a broader safety system that includes proper risk assessment, guarding, and control logic.

Standards and safety considerations: Safety interlocks are addressed in standards such as ISO 14119 for interlocking devices for safeguarding machinery and ISO 13849-1 for overall safety performance. Implementation should follow a risk assessment and incorporate fail-safe design, diagnostics, and regular testing. Regular maintenance is essential to preserve reliability.

Maintenance and reliability: Interlocks require periodic inspection, testing, and replacement of worn components. Potential bypass or tampering risks must be mitigated with proper installation, secure mounting, and routine verification. They are a component of broader machine safety systems rather than a standalone solution.