WO2021213880A1

WO2021213880A1 - Method and control system for maintenance of the door mechanism of an elevator system

Info

Publication number: WO2021213880A1
Application number: PCT/EP2021/059756
Authority: WO
Inventors: Alison Powers; Christoph Rüdiger; Kelly Truax; Mark Mc Carthy; Rory Smith
Original assignee: Tk Elevator Innovation And Operations Gmbh
Priority date: 2020-04-24
Filing date: 2021-04-15
Publication date: 2021-10-28
Also published as: DE102020205217A1

Abstract

Disclosed is a method and a system for determining the mechanical and/or electrical condition of an elevator door (110, 115) mechanism of an elevator system, comprising the steps of determining (200, 205, 210) a number of partial door reversals of movement, counting (215) the number of partial door reversals and comparing (220) a revealing count number of partial door reversals with a predetermined threshold value (225), wherein, in case of the threshold value (225) being exceeded, a corresponding maintenance request is being delivered (235) to a service center.

Description

TITLE

METHOD AND CONTROL SYSTEM FOR MAINTENANCE OF THE DOOR MECHANISM OF AN ELEVATOR SYSTEM

TECHNICAL FIELD

The invention concerns elevator systems for the transport of people or goods between floors or levels of a building, vessel, or other structure, which comprise at least one elevator car or cabin being equipped with doors, and particularly relates to a method and control system for determining or monitoring the operating condition of an according door mechanism of such an elevator system.

BACKGROUND

Preventive or predictive maintenance of an elevator door mechanism aims to reduce the degradation of its condition or performance and deterioration of the quality of door operation, caused by environmental effects, use and wear. Environmental factors affecting the condition of the door mechanism can be dust, dirt and temperature. If the elevator doors are not timely serviced or maintained, failure of the doors may result so that the elevator is no longer usable at all or the quality of operation of the elevator decreases decisively, e.g. the doors produce too much noise.

The scheduling of door maintenance is conventionally based either on regular servicing at certain intervals or on the extent of utilization, for example on the cumulative number of times the door has been opened and closed. In US 4,512,442 it is disclosed to count the number of times the doors are opened and closed and to send the revealed number to a maintenance center for scheduling of servicing.

Known servicing methods do not take into account the individual wear of elevators resulting from changing environmental factors and occasional rough treatment. Maintenance and repair of elevators have been scheduled only based on either client notifications about deterioration of elevator condition or on failure reports sent by automatic monitoring systems. Conventional methods of monitoring elevator doors are based on making inferences from events and status. In event-based monitoring, the sequences of occurrence of open, reopened, closed and locked states of the elevator door are monitored using on/off-type signals obtained from sensors, e.g. utilizing open and closed limit switches of the door. By these methods, the need for maintenance can be determined only on a rough level, typically in terms of either/or data. A need for maintenance is only determined when elevator operation has stopped completely because of a defective door.

EP 1 353868 A1 discloses a method for monitoring the condition of a door mechanism of an elevator system and for determining its need for maintenance. Signals from a control system for the door are measured both in a good operating condition (e.g. shortly after installation of the elevator system) of the door during opening and closing movements of the door. Hereby, a first set of characteristics descriptive of the operation of the door is generated. Accordingly, another set of such characteristics is measured later during normal operation of the elevator system. The two sets of characteristics thus generated are compared with each other and a diagnosis is performed to determine where and how the operation of the door and its components deviates from the operation of the door in the good operating condition. As a result, the need for servicing and a servicing date are established.

From US 10,196,236 B2, a monitoring system of an elevator system and a method of operating the monitoring system are known, by means of which usage data of an elevator door can be generated. The monitoring system includes a sensor for measuring at least one physical parameter of the environment of the sensor. The monitoring system further includes an evaluating unit, which determines an operating state of the elevator door by a course of the physical parameter over time.

Furthermore, EP 1 922278 B1 discloses a method for improving the performance of an elevator system, wherein the acceleration and/or velocity of the movement of an elevator door and the torque of a door motor moving the elevator door are measured and a dynamic model of the door is created. From an acceleration or velocity being determined based on the model, and from a measured acceleration or velocity, an error function is obtained and its minimum value be determined. In the dynamic model, kinetic parameters of the door are considered. By utilizing the calculated values of the kinetic parameters, the function of the doors is optimized. The kinetic parameters that are used in the optimization of the functions of the elevator door are selected from stored parameters and from an external selection signal, which is either a signal indicating a destination floor or a signal generated by a floor detector moving with an elevator car or cabin.

SUMMARY

The invention concerns a method and system for determining and/or monitoring the mechanical and/or electrical functioning/operating condition of an elevator door mechanism arranged on side of an elevator car or cabin and/or on side of a corresponding door mechanism arranged at a floor of an underlying building. The monitoring shall include the checking of a proper opening and closing operation of an elevator door, and is particularly aimed at providing the capability of predictive and/or remote maintenance of such a door mechanism in order to determine its need for maintenance.

Known elevator systems are already equipped with a remote maintenance capability, which enables mobile communication. Therefore, a technician can check and diagnose the functionality of the elevator, for example by mobile phone, and can determine which tasks of the maintenance process are necessary to perform. However, some maintenance aspects or processes of an elevator are yet to be implemented in such a remote maintenance system, like the process of reliably monitoring the (electro-) mechanical condition of an elevator door mechanism.

More particularly, the process of checking the opening and closing operation and speed is not yet supported by the currently known remote maintenance systems. These systems only monitor the timing of a door, but the actual driving force of a motor drive for moving the door is more important in order to prove a safe door operation. The necessity of an according maintenance process can be fulfilled by the solution presented herein thus making remotely performed maintenance of elevator doors more efficient.

The underlying idea is to determine the number of partial door reversals of movement, i.e. incomplete opening or closing operations, mainly such reversals of doors sometimes occurring during a normal door closing operation. Such abnormal operation situations can be caused by a passenger interaction, e.g. a late entering of the elevator cabin after the door closing operation has already started, or by an external event like a breakdown of the elevator or a short interruption of the power supply of the elevator system.

The idea is based on the present experience or knowledge that the mechanical or operating condition of an elevator door drive is mainly determined by such abnormal door operations (i.e. reversals) at maximum speed or other speeds, rather than the total number of normal operation events.

It has been further recognized that such abnormal operation events can be detected or determined reliably, e.g. using an existing or dedicated elevator control system. Hereby, existing operating data concerning door-operation-dependent motor drive characteristics, like the electric current needed for operating the motor drive of the doors, or existing sensors for monitoring the opening and closing of doors, can be utilized. Such abnormal operation events can also be detected using an additional, dedicated sensor system with an acceleration sensor, inertia sensor, or the like, being mounted at an elevator door, or a door hanger, or a door drive or motor drive of the door. The rotor of the motor drive can comprise a mechanical, electrical or optical sensor for measuring the rotation, in order to determine mentioned abnormal acceleration values. Only exemplary, an acceleration sensor or inertia sensor, or an electric sensor with e.g. an inductive or capacitive sensor element, or on optical sensor, can be arranged at the motor drive’s rotor for measuring the rotation of the rotor of the electric motor contactless.

It is noteworthy that a mentioned sensor is suitable and rather efficient or reliable to determine the occurrence of an underlying abnormal door operation event since a reversal of movement occurring e.g. during a maximum speed of movement corresponds to abnormally high acceleration values which can be captured safely.

According to one aspect of the proposed method, the number of such abnormal operating situations can be counted using a common digital counter. The revealed actual number of counts can be compared with an empirically predetermined threshold value of counts wherein in case of exceeding the given threshold, a corresponding maintenance request can be delivered to a service engineer, e.g. via a stationary or portable communication or computer device, like a desktop PC, smart phone, or tablet PC. Alternatively, the priority for a maintenance service call can be increased, based on the current count number.

According to another aspect of the proposed method, the actual number of abnormal operation event counts can be correlated with another physical property which is relevant for door operation or the use condition or electromechanical state of a door mechanism, e.g. the time that has passed since the last maintenance service or the total number of door operations. By this correlation, the reliability of the proposed method can be enhanced significantly.

Further proposed is a control system for monitoring the condition of an elevator door mechanism, which comprises a digital counter for counting said abnormal door operation events or situations. The determined count values are stored in a data storage in order to allow the mentioned digital evaluation of the determined count values to be accomplished by a comparator or evaluation unit. The comparator or evaluation unit compares an actual count value with an empirically predetermined threshold value and evaluates the necessity of a maintenance service for a respective elevator door. The control system further includes a communication unit, which, in case of the actual count value exceeding the given threshold, automatically sends a corresponding maintenance request to a stationary or portable communication or computer device of a service engineer, like a server computer or desktop PC, smart phone or tablet PC. Alternatively, the communication unit can change a priority bit or value for a maintenance service call, based on the evaluation result.

According to one aspect of the proposed control system, an accelerometer or acceleration sensor, inertia sensor, or the like, can be arranged at or attached to an elevator door, or to the motor axis of an electric motor for driving the opening and closing of the elevator door. A particular advantage of such a sensor is that the sensor is independent of the underlying elevator system installation, including an underlying elevator control system or an underlying electric motor.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features and advantages of the invention are understood within the context of the Detailed Description, as set forth below. The Detailed Description is understood within the context of the accompanying drawings, which form a material part of this disclosure, wherein:

FIG. 1 shows an embodiment of the elevator control system according to the invention, by way of a block diagram.

FIG. 2 shows an embodiment of the method according to the invention, by way of a flow diagram.

DETAILED DESCRIPTION

The elevator system schematically shown in FIG. 1 includes an elevator cabin 100 arranged in an elevator shaft 105. The elevator cabin 100 is depicted in a front view in order to better illustrate an underlying elevator car door mechanism including two elevator doors 110, 115 in the present embodiment. Of course, the present invention can also be applied to an elevator system or door mechanism with only one door or even more than two doors. In addition or alternatively, the present invention can also be applied to a door mechanism being arranged at each of the floors of an underlying building.

The operation of the shown door mechanism, including the two elevator doors 110, 115, is controlled by an elevator control unit 120, which in the present embodiment is arranged on side of the shown elevator cabin 100. However, the control unit 120 can also be arranged at a wall of the elevator shaft 105, or a main control room residing e.g. on the top of the shaft 105. The control unit is connected to two motor drives 125, 130 via respective control or communication lines 135, 136. The motor drives 125, 130 serve for the opening and closing movements of the door doors 110, 115. The present elevator system further includes two schematically shown acceleration sensors 140, 145, which, in the present embodiment, are mounted directly on the two doors 110, 115. These sensors 140, 145 allow to measure or monitor the operation condition and the operation characteristics of lateral movements of the two doors 110, 115.

It has to be mentioned that the present can also be implemented with only one acceleration sensor mounted on one of the two doors 110, 115, because the two doors 110, 115 are operated essentially symmetrically regarding the opening and closing movements.

It is noteworthy that the lateral movements of the two doors 110, 115 can also be measured using a sensor system with an acceleration sensor, inertia sensor, or the like, being mounted at an elevator door, or a door hanger, or a door drive or motor drive of the door. Hereby, the rotor of the motor drive can comprise a mechanical, electrical or optical sensor for measuring the rotation, in order to determine mentioned abnormal acceleration values. Only exemplary, an acceleration sensor or inertia sensor, or an electric sensor with e.g. an inductive or capacitive sensor element, or on optical sensor, can be arranged at the motor drive’s rotor in order to allow contactless measurements of the rotation of the rotor of the electric motor.

The signals provided by the two sensors 140, 145 are transmitted to the control unit 120 via communication lines 150, 151 in order to detect mentioned abnormal operating events of the doors 110, 115. The communication lines 150, 151 shown, as indicated by the dotted lines, can be implemented either using known wired or wireless communication technologies. These abnormal events are mainly reversed opening movements of the doors 110, 115 occurring during a normal door closing operation. Such events are detected by means of the two sensors 140, 145, based on exceptionally or relatively high door acceleration values that are caused, in the present example, by the sudden reversal from the closing direction to the opening direction. These sudden reversals particularly cause relatively high mechanical and/or electrical load or wear on the underlying door mechanism, including both the mechanical and electrical components of the door mechanism.

The control unit 120, as depicted in its enlarged view right-hand, includes a digital counter 155, which counts such abnormal operation events, or measured acceleration signals. The current count values, or the measured acceleration signals, are stored in a local data storage 160. In addition, the control unit 120 includes a digital comparator 165, which compares a current count value recently stored in the data storage 160 with a predetermined, e.g. previously and empirically determined, threshold value 170. The output signal or information 175 delivered by the comparator 165 is utilized after that to increase the priority for planning the maintenance of the door mechanism or to trigger a maintenance service, which is accomplished in the control unit 120 in the present embodiment. In a further embodiment, the comparator 165 can compare a current count value with two or even more existing threshold values, wherein each of these threshold values relates e.g. to a specific priority level for planning the maintenance.

The control unit 120 of the elevator system shown in FIG. 1 is connected with a (not shown herein) remote maintenance center by means of a communication unit 180. The transmission 185 of the information 175 delivered by the comparator 165 to the remote maintenance center is effected using known transmission protocols based on a telephone line or a wireless connection.

When information is sent from the control unit 120 to the remote maintenance center for analysis of such information, the data can be transmitted e.g. in connection with a test call on an emergency telephone line. If the results of signal analysis are sent to the remote maintenance center as in the configuration presented in FIG. 1, the data can be transmitted only when the values of the characteristics differ from the normal values beyond a mentioned threshold limit, in order to save according data traffic.

It has to be mentioned that, according to an alternative embodiment, the evaluation of the measured door acceleration signals, in order to count abnormal door operation events, can be accomplished on the side of the remote maintenance center. In such an embodiment, a mentioned evaluation unit and comparator have to be arranged on side of the maintenance center in order to perform the two different comparisons with corresponding threshold values described in the following. In such an embodiment, the control unit 120 can be a common control unit as known in the art, which then only transmits stored count values on a temporal basis to the remote maintenance center, which evaluates the transmitted count values on site.

It is further mentioned that, according to another alternative embodiment, only the evaluation of the count values can be accomplished on side of the remote maintenance center.

Based on the results of the evaluation of the count values, the need for maintenance is determined, either on side of the elevator system or on side of the remote maintenance center. Based on the determined need for maintenance, a servicing date, i.e. a date by which the doors of the underlying elevator system should be serviced, is determined. This prevents malfunctions and guarantees an acceptable level of performance and safety of the elevator system.

The determined servicing date can also be compared with a preliminary servicing visit schedule stored in a database arranged on side of the remote maintenance center. If necessary, an earlier date is assigned for a scheduled servicing visit. For the servicing visit, instructions regarding the relevant doors are generated from the evaluation results, as to which parts of the door mechanism need servicing.

According to the procedure shown in FIG. 2, the acceleration signals, or corresponding sensor data, provided by the at least one acceleration sensor 140, 145 depicted in FIG. 1, are gathered 200 either continuously or only during a pending door movement operation. According to the latter option, the control unit 120 can trigger the gathering of the sensor signals or data only when a door movement occurs, so that the total amount of gathered acceleration data is limited considerably.

The gathered acceleration data are compared 205 with an empirically predetermined first threshold value 210. The first threshold value 210 can be an absolute number or a positive/negative number. In the latter case, it is possible, to evaluate the acceleration direction in order to distinguish mentioned reversals of a pending closing operation to a sudden opening operation of the elevator doors from other door movement events with relatively high acceleration values. Such other events are the relatively high accelerations of the doors at the very beginning, and at the very end, of a normal opening or closing operation. If the comparison 205 reveals that the first threshold value 210 is not exceeded, it is jumped back to the beginning of the procedure (before step 200).

Otherwise, if the first threshold value 210 is exceeded by a current acceleration value, then a digital (binary) counter for counting underlying abnormal door operation events is increased 215 by . In the following step 220, the current count value of the digital counter is compared with an empirically predetermined second threshold value 225. If the comparison step 205 reveals that the second threshold value 225 is not exceeded, it is jumped back to the beginning of the procedure (before step 200) again. Otherwise, in step 230 the priority for performing an according door maintenance is set “high”, e.g. using a dedicated binary priority bit. As a consequence of the higher priority, the maintenance plan for the underlying elevator system is amended 235 accordingly.

Claims

1. A method for determining the mechanical and/or electrical condition of an elevator door (110, 115) mechanism of an elevator system, comprising the steps of determining (200, 205, 210) partial door reversals of movement, counting (215) the number of partial door reversals and comparing (220) a revealing count number of partial door reversals with a predetermined threshold value (225), wherein, in case of the threshold value (225) being exceeded, a corresponding maintenance request is being delivered (235) to a service center.

2. Method according to claim 1 wherein the priority for a maintenance service call is increased (230) based on a current count number (215).

3. Method according to claim 1 or 2 wherein the number of partial door reversals is determined using an elevator control system (120) and wherein operating data concerning door-operation-dependent motor drive characteristics and/or existing operating data of sensors for monitoring the opening and closing of at least one door (110, 115) are/is utilized.

4. Method according to claim 3 wherein the existing door-operation-dependent motor drive characteristics is the electric current needed for operating a motor drive (125, 135) of the door (110, 115).

5. Method according to any of the preceding claims wherein the number of partial door reversals is determined contactless using an additional dedicated sensor system (140, 145) with a mechanical, electrical and/or optical sensor (140, 145) for measuring the movement of a door and/or for measuring the rotation of a motor drive (125, 135) of the door (110, 115).

6. Method according to claim 5 wherein the dedicated sensor system (140, 145) includes an acceleration sensor and/or an inertia sensor, being mounted at an elevator door, or a door hanger, or a door drive or the motor drive (125, 135) of the door (110, 115).

7. Method according to claim 5 or 6 wherein a rotor of the motor drive (125, 135) comprises a mechanical, electrical and/or optical sensor for measuring the rotation of the rotor, in order to determine a partial door reversal of movement, based on an abnormal acceleration value.

8. Method according to any of the preceding claims wherein a revealing count number is correlated with another physical property, which is relevant for door operation or the use condition or electromechanical state of the elevator door (110, 115) mechanism.

9. An elevator control system for determining the mechanical and/or electrical condition of an elevator door (110, 115) mechanism of an elevator system, comprising an evaluation unit (120) for determining partial door reversals of movement, a counter (155) for counting the determined partial door reversals, and a comparator (165) for comparing a determined count value with a predetermined threshold value (170), wherein the necessity of a maintenance service for a respective elevator door (110, 115) is evaluated.

10. Elevator control system according to claim 9, comprising a communication unit for automatically sending a maintenance request to a service center, if a determined count value exceeds the threshold value (170).

11. Elevator control system according to claim 9, comprising a communication unit for automatically changing a priority value for a maintenance service call to a service center, if a determined count value exceeds the threshold value (170).

12. Elevator control system according to any of claims 9 to 11, comprising a data storage (160) for storing at least two determined count values and a comparator (165) for comparing the at least two count values.

13. Elevator control system according to any of claims 9 to 12, for controlling an acceleration sensor and/or inertia sensor (140, 145) being arranged at or attached to the elevator door (110, 115), or to a rotor of a motor drive (125, 135) for driving the opening and closing of the elevator door (110, 115), in order to determine partial door reversals of movement of the elevator door (110, 115).