Wednesday, 29 January 2020
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Innovations in door locks

Additional requirements from new standards and market demands have spurred Kronenberg to implement several innovations in the door lock field.

Compact CLF door lock with central bolt and symmetrical housing. (Photo: © Kronenberg)

These are above all the especially compact door lock CLF, the motor drive of the DLF1MO and CLFMO door locks and the RKMO retiring cam. On top of this, all Kronenberg door locks have undergone consistent upgrading to permit a pull rope or control wire to be connected for an external emergency unlocking device, including matching accessories such as triangle unlocking units, control wires and retrofitting sets.

Integrated emergency unlocking triangle

Kronenberg met calls for a compact lock, mainly for lifts in private residential construction, by developing the CLF. The bolt is located in the middle of the just 181 x 65 x 34 mm housing and on top of this the attachment is symmetrical. All that still needs to be decided during planning is whether the actuation in the CLF should be on the left or right side.

Compared to a DLF1, the bolt stroke and as a result the actuation force has been greatly reduced, without dispensing with a positive, two-stage fail-safe lock device. The integrated emergency unlocking triangle can if desired be implemented at the same position with electrical monitoring according to EN 81-21.

External triangle emergency unlocking device

An emergency unlocking triangle in horizontal installation may not be installed higher than 2 m above the landing floor according to current technical requirements (EN 81-20). Accessibility of the unlocking mechanism from the shaft is now standardised.

HandwerkIn view of this, all Kronenberg door locks have been expanded with option .14 for connecting a control wire and option .5 for connecting a pull rope to unlock the door.

Type NE triangle emergency unlocking units are used to actuate the rope pull or control wire attached to the lock. On request, they can be equipped with a safety switch to monitor the emergency unlocking device, as required in EN81-21. An option with bistable switching function and electrical resetting is possible too. Other accessories for coupling the rope pull or control wire to existing tie rods permit easy retrofitting of such functions.

Door locks with motor drive

The motor three-phase ac drive in the DLF1MO door lock has proven to be a success. It is not only used as a landing door lock, but also to keep the car door closed and locked. The compact CLF door lock is now available with a CLFMO flange-mounted motor assembly.

The motor drives are particularly quiet and energy-saving and therefore simplify control and potential battery buffering. If controlled 24 V dc voltage is used, the approximately one-second long unlocking process needs less than 1 A. The low holding current (approx. 0.17 A) can be on for any length of time (100% on-period).

Retiring cam with motor drive

It was then a logical step to replace the large magnets of a retiring cam with a flat motor drive too. The RKMO retiring cam will be unveiled at interlift 2017.

Here too less than 1 A at 24 V will be needed for retracting the cam to a total height of just 50 mm. The wide voltage range of 100-240 V AC/DC can be covered with just one device with an optionally integrated power supply unit.

Adaptations for modernisation and retrofitting

The range of adaptations available is being continually expanded for the replacement of third party locks that may no longer be marketed or no longer meet current technical requirements (EN 81-20/-50). Additional options have been created here by the compact CLF to avoid replacing complete doors. Such conversions always have to be considered on a case-by-case basis, since in practice divergences can also be found in supposed standard applications.

The EN 81-20/-50 standard series has now finally replaced the previous basic lift standards. This above all has effects in the field of lift doors. Kronenberg GmbH as a manufacturer of door locks will be presenting several innovations to simplify realisation of the state of the art in new construction as well as in the field of retrofitting and modernisation and further enhance the level of safety.

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