Ohutusinterlocks

Ohutusinterlocks, or safety interlocks, are devices and systems designed to prevent machinery or processes from operating under unsafe conditions. They are used to enforce guards, doors, gates, and other safety-related barriers, ensuring that a hazardous area cannot be accessed or that a protective function remains engaged while the equipment is in use.

They typically combine a mechanical or electrical interlock with a sensing and control element. When a guarded door or gate is opened or a protective device is moved, the interlock changes state and prevents starting or immediately stops the machine. Some interlocks are latching, requiring a deliberate action to reset, while others are non-latching and re-enable automatically when the safety condition is restored. Variants include door interlocks, gate interlocks, access-key interlocks, and safety switches that monitor position and guardedness.

Standards and reliability: Safety interlocks are covered by international standards such as ISO 14119 for mechanical interlocks, ISO 13849-1 for safety-related parts of control systems, and ISO 12100 for risk assessment. They are designed to achieve defined performance levels or SIL ratings depending on risk, and their reliability is considered in the machine's safety design (often expressed as PL or SIL).

Applications and limitations: They are widely used in manufacturing, packaging, and process industries to guard robotics, presses, conveyors, and enclosures. Proper use includes risk assessment, regular testing, and maintenance to prevent bypass, tampering, or degradation. Interlocks are an essential component of a broader machine safeguarding strategy but do not by themselves replace comprehensive safety management.