Suojalukitus

Suojalukitus, or protective interlock, is a safety device used on machinery to restrict access to hazardous areas. It is typically mounted on a protective guard or access door and is designed to prevent machine operation while the guard is open or not in the correct state.

The core function of a suojalukitus is to ensure that a machine does not start or continue operating while a guard is open, and to require a safe condition or explicit reset before re-enabling operation. Interlocks can be purely mechanical, purely electrical, or a combination of both. Modern implementations often include safety-rated electronic monitoring and are integrated into the machine’s control system, so that a fault in the interlock or its circuit triggers a stop.

Common types include mechanical latch interlocks that lock the guard in place, and electrical interlocks that use sensors and safety circuits to verify guard position. Some designs feature safety relays or programmable safety controllers and may provide diagnostics and tamper resistance. Important concepts in suojalukitus design include reliable guarding, fault detection, and secure re-engagement after access.

Standards and regulation in many regions require protective interlocks as part of overall machine safety. In the European Union, compliance with the Machinery Directive and related standards such as EN ISO 14119 and ISO 13849-1 is typical, with emphasis on risk assessment, safety integrity, and appropriate PL/SIL ratings.

Applications of suojalukitus span manufacturing, metalworking, woodworking, and packaging lines, where safeguarding operators and preventing accidental exposure to moving parts are essential. Maintenance involves regular testing, inspection for wear or tampering, and timely replacement of worn or faulty components to preserve safety performance.