What are the ALPHA & BRAVO?
The ALPHA and BRAVO are fully mechanical interlock blocking devices for safeguarded areas.
By mounting the ALPHA on a door that is already equipped with a safety switch or sensor, entrapment in a safeguarded area can be prevented. The BRAVO has been specially developed to prevent light curtains from resetting as long as someone is present in the zone.
Fully mechanical solution
Easily increase your safety
For doors and light curtains
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ALPHA mechanical interlock blocking device for doors
This universal blocking system prevents machines from being unintentionally restarted during maintenance and activities.
The ALPHA interlock blocking device for hinged doors can easily be retro-fitted to any entrance door to a safeguarded area (which is already equipped with a safety switch) and obliges operators to carry a safety key when entering the area.
- Compulsory Lockout-Tagout
- Fully mechanical
- Easy to mount on any door
- Mandatory key removal
- 200,000 unique key codes
- Full stainless steel 316
- Very robust design
- Version for hinged doors


Door closed
The ALPHA interlock blocking device prevents opening an access door until the unique coded key is turned and extracted. The ALPHA then block the door from closing and in doing so switching the safety contact of the door switch until the safety key is returned in the lock.

Door open
The ALPHA ensures the door can only be opened when the safety key is removed. As long as the operator is present in the safeguarded area (with the safety key), the door cannot close and the machine cannot restart.

Safety Switch
ALPHA
Increase your safety
De ALPHA insluitbeveiliging kan eenvoudig geplaatst worden op bestaande deuren die reeds zijn voorzien van een veiligheidsschakelaar of veiligheidssensor zonder veiligheidssleutel functie.

Safety Switch
Light Curtain
ALPHA or light curtain?
In some cases, with full-body access, the ALPHA interlock blocking device can be used as an alternative to light curtains that serve as person detection.

ALPHA mechanical interlock blocking device for sliding doors
This blocking device for sliding doors prevents machines from being unintentionally restarted during work.
The ALPHA interlock blocking device for sliding doors can easily be retro-fitted to any entrance door to a guarded area (which is already equipped with a safe door switch) and obliges operators to carry a security key when entering the area.
- Compulsory Lockout-Tagout
- Fully mechanical
- Easy to mount on any door
- Mandatory key removal
- 200,000 unique key codes
- Full stainless steel 316
- Very robust design
- Version for sliding doors
Hoe werkt de ALPHA voor schuifdeuren?

1. The access door is closed, machine is in use. The coded safety key is locked. The safety contacts of the existing door switch are closed.

2. Sliding door can be opened up to the end of the “hook”. The fixed knob prevents the door from opening completely. It opens the safety contacts of the existing switch.

3. Turn the key to rotate the blocking plate downwards and unlock the door completely. The locking plate also rotates out and prevents the door from closing.

4. The safety key can now be removed. The blocking plate can also be fitted with up to 2 personal padlocks if several operators want access.

5. As long as the key is removed (and optionally the padlocks are inserted), the door cannot be closed, which means that the safety contacts of the safety switch cannot be closed either.
Prevent entrapment of operators in machinery
Often a safety padlock is used to prevent entrapment during maintenance. The ALPHA makes the use of a safety key mandatory.
The major drawback to using lockout tagout/safety padlocks to prevent the restart of a machine is that it is not mandatory.
For access to protected areas, machines or processes with “full body access”, the ALPHA interlock blocking device ensures mandatory key removal before access can be granted.


BRAVO mechanical interlocking device for light curtains
This universal interlocking system ensures that the light curtains’ beams are interrupted as long as an operator is present in the protected area.
The BRAVO containment device is a fully mechanical retro-fit solution to prevent the risk of containment and unintentional restarts of light curtains. The BRAVO allows operators to carry a safety key with them when entering the safeguarded area behind the light curtain.
- Fully mechanical
- Easy to mount at every light curtain
- Disrupts the light curtain beams
- 200,000 unique key codes
- Full stainless steel 316
- Very robust design
- Different sizes of blocking plates for mounting on column or protection profile

Light curtain in operation
The Bravo interlock blocking device is easily installed using sliding bolts on the side of the light curtain. Installation on a wall guard is also possible, as various sizes of blocking plates are available as standard. By turning the coded key, the interlock blocking plate moves in front of the optical beam, preventing the safety contacts of the light curtain from being switched.

Light curtain during maintenance
The coded key can only be removed when the interlock blocking device interrupts the beams of the light curtain. The operator takes this safety key with him into the guarded area, making an unintentional restart or reset of the machine impossible. When several operators enter the room, the spring-loaded dust cover can be fitted with 2 padlocks to prevent entry of the key and thus the unblocking of the light beam.
How does the BRAVO containment system work?

1. When using safetylight curtains for full-body detection, there is a risk of an unintended machine start when the operators are in the safeguarded area (entrapment hazard).

2. The Bravo (PBL) interlock blocking device is fully mechanical and can be easily retro-fitted with only 2 fixings on or next to the light curtain’s receiver.

3. By turning the key, the blocking plate comes in front of the light curtain and blocks the beams. The key can only be removed when the blocking plate blocks the light curtain.

4. The operator takes the released key into the safeguarded area as a personal protection against an unexpected restart. As long as the key is removed, the blocking plate is locked.

5. When more operators need to enter the safeguarded area, safety padlocks can be placed around the lockable dust cover to prevent key entry and thus a restart.