# On-Demand Maintenance Method Using Fault Prediction to Reduce Elevator Entrapment
## 4 On-Demand Maintenance Method
### Implementation of On-Demand Maintenance  
In selecting elevators for on-demand maintenance testing, the number of maintenance enterprises and maintenance project sites was reasonably controlled to reduce the field experiment's implementation difficulty effectively. Relying on the database of City H's Elevator Emergency Response Center, the selection focused on elevator maintenance enterprises. Through in-depth analysis and comprehensive comparison of various dimensions such as maintenance volume, maintenance quality, and the scope of business operations, elevators maintained by two enterprises, A and B, in City H were chosen as test samples. Based on the latest data in the elevator database, the samples were combined with project sites as the main body. During the combing process, it was noted that some project \begin{table}
\begin{tabular}{c c} \hline \hline
**Projects** & **Maintenance Contents** \\ \hline Electrical switching and & \begin{tabular}{c} Inspect and clean electrical switches to prevent switch \\ faults due to dust and moisture. \\ \end{tabular} \\ \begin{tabular}{c} Test electrical wiring for insulation resistance with \\ inspection tools to ensure the wiring is in \\ good condition. \\ \end{tabular} \\ \begin{tabular}{c} Replace aged electrical wiring to avoid short circuits \\ and false connections. \\ \end{tabular} \\ \hline Door system maintenance & \begin{tabular}{c} \#Check the opening and closing flexibility of elevator \\ doors and the reliability of door locks to ensure proper \\ operation of the door system. \\ \#Lubricate the door guide rails to reduce friction \\ and noise. \\ \#Clean up foreign objects in the door cracks to prevent \\ door jamming and deformation. \\ \#Check whether there is severe wear and tear on the \\ door roller on the door hanging plate, and replace it. \\ \#Check whether the door guide rail is deformed or \\ loosely skewed, and correct it if it is. \\ \#Check whether the two rollers of the door lock and the \\ door cutter are tightly affixed; if not, make adjustments. \\ \#Check the wear and tear of the door chain, door belt, \\ and wire rope to avoid breakage. \\ \#Check whether the status of each relay of the door \\ system is normal. \\ \#Check whether the light curtain or safety contact plate \\ action is standard. \\ \hline Maintenance of traction and & \
\begin{tabular}{c} Check and lubricate the guide sheave and counter rope \\ sheave to reduce wear and noise. \\ Adjust the verticality and spacing of the guide rails to \\ ensure smooth running of the car. \\ \end{tabular} \\ \hline Safety device inspection &
\begin{tabular}{c} Inspect and test safety devices, such as speed limiters, \\ safety clamps, and buffers, to ensure their reliability. \\ Overload protection devices are calibrated to prevent \\ overloading of the elevator. \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 10: On-demand maintenance protocol for red code elevators (“#” mark is the key items). sites had complex situations such as changes in maintenance units, division of areas within the project sites, but not uniformity in maintenance units, and deviations in the number of elevators. To ensure the accuracy and reliability of the study, these project sites with anomalies were eliminated. After rigorous screening and cleaning, the final sample of elevators included 456 elevators in seven project sites of enterprise A and 306 elevators in seven project sites of Enterprise B, for a total of 762 units. Predictions of entrapment faults were made for a sample of elevators using existing entrapment fault prediction algorithms, and a report of entrapment risk indices was generated. In this section, the red code elevators were predicted to have a high incidence of entrapment faults and were labeled and categorized using data from the September 2024 entrapment risk index report.