Door lock DLF2 with connection for control wire. (Photo: © Kronenberg)

Door lock DLF2 with connection for control wire. (Photo: © Kronenberg)

Emergency unlocking for door locks


New requirements will be binding for the installation height of emergency unlocking for lift doors from 1.9.2017. New regulations will then also apply to the unlocking of the shaft door from the pit ladder.

Door locks for landing doors receive first mention in the Lift Directive 2014-33-EU in the list of safety components. They may only be distributed from 1.9.2017 provided a valid EU or EC type approval test certificate is available in which the new lift standards EN81-20 and EN81-50 are listed as test basis. What has changed now as a result of the new lift standards for locks?

External emergency unlocking triangle

If you compare the type approval tests for locks under the old and new standard series, the customary tests have not changed. However, there are other new requirements that affect locks. These above all refer to the position of the emergency unlocking triangle and the possibility of unlocking the door from the pit ladder. Each form of unlocking should be possible from a secure stance to minimise the risk of a fall into the shaft for the maintenance personnel.

Consequently, EN81-20 requires an emergency unlocking triangle may only be installed up to a height of 2 m above the floor of the stop. This requirement applies primarily to door locks of hinged doors installed in door imposts, which is above all the case with two-leaf hinged doors. The emergency unlocking triangle normally integrated in the door lock may no longer be used here; an external emergency unlocking triangle must be installed at a lower height and coupled to the lock.

“NE” triangle actuators

“NE” triangle actuators from Kronenberg are suitable for this purpose. They are normally built into the door frame and connected to the door lock via a control wire. Apart from the basic version, there are additional versions with electric monitoring of the emergency unlocking, as called for in EN 81-21. An idle mode ensures that the safety switch (positively driven NC contact) opens before the pull rope actuates the lock. A bi-stable switching function can also be realised with resetting via an electric switching impulse.

The door lock must have a corresponding connection to permit a door lock to be operated via these external triangle actuators with a pull rope or control cable. Consequently, Kronenberg has supplemented in all door locks the emergency unlocking design “5” for connecting a pull rope and “14” for connecting a control wire. In door locks with integrated operation via electric magnet or electric motor, the emergency unlocking design “5” also has the function of permitting unlocking from the shaft without tools by hand.

More supplements in the area of emergency unlocking

According to EN 81-20, unlocking of the shaft door should be possible safely at a height of 1.8 m and a maximum of 0.8 m laterally from the pit ladder. If this is not possible, the requirement can be realised by a pull rope connected to the door lock or a control wire with an end grip. A combination with the above-mentioned triangle actuators is possible too. In order to provide a comprehensive range of accessories here, Kronenberg has expanded its product range with pull ropes and control wires of its own manufacture, rope grips for unlocking, adjusting screws and mounting angles.

Admittedly, nothing has changed in the functional principle as a result of the new lift standards and the type approval tests for Kronenberg door locks that have been tried-and-tested for decades, but there have been more supplements in the area of emergency unlocking and its monitoring. This can on the one hand be integrated in the door lock, but also externally at another place by the “NE" emergency unlocking units. In this way, the state of the art can be reproduced with all Kronenberg door locks in different manners.

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