February 2020
Kübler introduced two approaches at once in a concept study: the replacement of the mechanical speed governor and more safety for fitters and maintenance through the easy creation of protective spaces.
The lift industry is changing. Digitalisation and functional safety technology permit completely new lift concepts. Numerous mechanical components have already been eliminated by SIL3-certified sensor systems today, which saves time and costs.
Apart from encoders and bearingless encoders for lift motors, Kübler provides digital shaft copying systems for different requirements up to 392 m: from the basic Ants LEB and SIL3-certified Ants LES version for absolute positioning of the lift car to the Safe System, consisting of SIL3-certified LES and evaluation unit PSU for realising lift and safety functions according to EN 81-20/21/50.
Based on customer discussions with lift and control manufacturers, Kübler has developed a concept study with other leading lift sector technology companies, which is intended to represent a further evolution stage in terms of safety.
Today, many mechanical components such as limit switches, have been replaced by reliable sensor systems. The mechanical speed governor was also eliminated in the concept study.
Apart from the pure recording of the absolute position of the lift car by the digital shaft copying system Ants, the triggering speed at 125 percent of the nominal speed is in addition reliably identified and the electromechanical safety gear (ESG) triggered. Programming of the nominal speed is just as simple as the easy fitting of the Ants shaft copying system.
The mechanical speed governor and its individual components, such as the governor rope or tensioning weight, can be eliminated by the digital triggering through the Ants shaft copying system. This results in a reduction of the overall costs and of time and costs as well as part of installation and maintenance.
Fitters are exposed to unforeseeable risks during the installation of lifts. The concept study will not only replace the mechanical speed governor, but also stands for more protection in installation and maintenance and as a result for more safety for fitters and maintenance personnel.
Safety for fitters already begins from the time the car frame is fitted. During this phase of fitting, a chain hoist is used instead of a motor. This permits the fitter to travel to the different floors or to the shaft head and shaft pit.
In the concept study, Kübler describes how the digital shaft copying system can be used. After fitting of the Ants system, the sensor (irrespective of the controller) only needs to be connected to the supply voltage and electromechanical safety gear (ESG). The ESG is reliably triggered upon activating the ‘shield mode’ in the event of unintended movement of just 0.5 m/s (factory setting).
The position of the lift car is fundamental when working in the shaft head or shaft pit. The sensor system does not just monitor speed. In shield mode, the ESG can also be triggered on the basis of position changes of about 5 cm (factory setting). This is especially important if fitters are working simultaneously on and under the car. Consequently, the feeling of safety is not only noticeable for passengers during the trip, but also for fitters during installation.
Digitalpaper
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