Entrapment protection for light curtains

Entrapment Protection for Light Curtains: Prevent Unintended Machine Restart

Why additional protection is required for light curtains

In modern production environments, light curtains are widely used as access safeguarding devices. However, standard light curtains only detect beam interruption during entry or exit. Without an additional mechanical safeguard, there is a risk that a machine may be reset or restarted while an operator is still inside the hazardous area.

The BRAVO entrapment-protection system provides a robust, fully mechanical solution that eliminates this risk. By physically interrupting the light curtain beam, the system ensures that restart is impossible until the safety key is returned.

How does the BRAVO entrapment-protection system work?

BRAVO is mounted directly next to or onto the light curtain and operates entirely mechanically:

• The operator turns the key, which inserts a mechanical blocking plate into the light curtain’s optical field.
• The key is removed and carried into the safeguarded area as a personal safety key.
• As long as the key is not returned, the light curtain beam remains physically blocked.

This mechanism ensures the light curtain cannot reset while someone remains inside the protected zone. Because the system is independent of electronics, PLCs or wiring, it remains reliable even during power loss, control faults or electrical disturbances.

Fully mechanical and extremely robust

Constructed from 316 stainless steel, BRAVO is designed for demanding industrial conditions such as:

• Dusty, dirty or humid environments
• Hygienic areas with frequent washdown processes
• ATEX hazardous zones

The purely mechanical design makes the system low-maintenance, wear-resistant and suitable for applications with high vibration levels or extreme temperatures.

Mandatory key removal ensures operator safety

BRAVO enforces removal of the safety key whenever the protected area is accessed. The key can only be removed when the blocking plate is positioned inside the optical field. As a result, restart is mechanically impossible until the operator returns the key. For multi-person entry, additional padlocks can be added to create a group-lock configuration.

Simple retrofit installation

The system is engineered for quick installation on existing assemblies. It can be mounted using T-slot nuts, brackets or profile fasteners. No electrical modifications, sensor changes or PLC integration are required. BRAVO is available with multiple blocking-plate dimensions to match virtually any light curtain.

Compatible with all standard light curtains

BRAVO is universally compatible with light curtains that comply with EN ISO 13855. It enhances the safety function without altering the original safeguarding device or its control logic.

Practical example: maximum safety in an assembly cell

An operator regularly works behind a light curtain. Without additional protection, a colleague could unintentionally reset the machine while the operator is still inside. With BRAVO, the operator removes the key before entering. The physical blocking plate keeps the optical field interrupted until the key is returned—making restart impossible.

The benefits of the BRAVO system

• Fully mechanical: no electronics, wiring or failure-prone components
• Mandatory key removal: guaranteed physical presence detection
• Physical beam interruption: reliable operation without sensors or software
• Quick retrofit installation: no modifications required
• 200,000 unique key codes: registered per ISO/TS 19837
• Supports padlock addition: suitable for multi-person access
• Ideal for stainless steel, ATEX and hygienic applications

Expert guidance from our machine-safety specialists

Our team can assist you in selecting the appropriate entrapment-protection solution for your installation. Whether you work with light curtains, hinged doors or sliding doors, we provide support for configuration, implementation and compliance with PL e, SIL 3 and related machine-safety standards. Contact us for technical support or a tailored quotation.