WO1999043587A1

WO1999043587A1 - A method and a device for monitoring the operation of an elevator

Info

Publication number: WO1999043587A1
Application number: PCT/BE1998/000026
Authority: WO
Inventors: Lars Odlen
Original assignee: Teclion
Priority date: 1998-02-24
Filing date: 1998-02-24
Publication date: 1999-09-02
Also published as: AU6286198A

Abstract

The present invention relates to a method and a device for monitoring the operation of an elevator system provided with a safety circuit forming a closed loop, said safety circuit being provided for enabling the operation of the elevator when a current passes through said safety circuit, said method comprising the steps of: retrieving an electrical signal indicative of an event within the elevator system; storing the retrieved signal; and transmitting the stored signal to a remote station. According to the invention, said signal is retrieved from said safety circuit of the elevator system.

Description

- 1 -

"A method and a device for monitoring the operation of an elevator"

The present invention relates to a method for monitoring the operation of an elevator system provided with a safety circuit forming a closed loop, said safety circuit being provided for enabling the operation of the elevator when a current passes through said safety circuit, said method comprising the steps of : retrieving an electrical signal indicative of an event within the elevator system; storing the retrieved signal; and transmitting the stored signal to a remote station. Such a method is for example known from EP-S-0 298 784 assigned to Otis Elevator Company. According to this method, a plurality of signals indicative of events within the elevator are retrieved and supplied to a signal processor for monitoring the operation status of the elevator. Each signal is indicative of an event, for example an indication if the door at a certain floor is opened or closed. The term "event" must understood as an electrical power consuming event in order to be able to form an electrical signal.

Such a method presents however several drawbacks. First, a plurality of signals have to be monitored so that for installation of this system, a plurality of sensing devices are required, i.e. one per signal to be measured, which renders installation relatively complex and expensive. In order to have the system operable, the logic within the signal processor must be specifically programmed or designed in function of the number and type of sensing devices and signals installed, which is relatively cumbersome. In other words, both installation and - 2 - programming of the monitoring system depends on several parameters, i.e. the type of elevator, the number of floors in which it is installed, etc. and is therefore a cumbersome and expensive operation.

The object of the present invention is to provide a generic method for monitoring the operation of an elevator, which enables a simple installation and is hence less expensive.

To this object, the method for monitoring the operation of an elevator system according to the invention is characterised in that said signal is retrieved from said safety circuit of the elevator system. Since one signal from the safety circuit of the elevator system is used, which safety circuit is present in a majority of elevators, this method suits for most elevator types. The installation is rendered very simple since only one sensing device is required for measuring one signal from the safety circuit. The operation is rendered very simple since the signal is retrieved from a circuit which is already present in most elevator types, so that specifically programming the processor means in function of the type of elevator is not required. The signal can directly be retrieved from the safety circuit itself for example by a voltage or current measurement. In a first preferred embodiment of the method according to the invention, said signal is retrieved by determining a current passing through said safety circuit. This facilitates even more the installation since this current sensing may be achieved anywhere in the safety circuit and providing thereby the same results. Preferably, said current is determined by means of a magnetic sensing device. In particular, a hall sensor is used as magnetic sensing device, since it allows for both DC and AC detection. This enables to avoid galvanic contact between the sensing device and the safety circuit, which is safer in case the sensing device is short circuited, - 3 - since the integrity of the safety circuit is critical to the safety of the elevator.

In a second preferred embodiment, the method according to the invention comprises the step of determining, by means of said signal, a first histogram showing, for a plurality of runs of the elevator, a number of runs of the elevator in function of the elevator runtime. Such a histogram may, on the one hand, be used for maintenance purposes since those parameters are indicative of the wear of materials, and, on the other hand, for determining malfunctions such as starting failures, stopping accuracy of the elevator car near the floors and stopping of the elevator between two floors.

In a third preferred embodiment, the method according to the invention comprises the step of determining, by means of said signal, a second histogram showing, for a plurality of runs of the elevator, a number of runs of the elevator in function of a predetermined time pattern. The time pattern is for example the time of the day, possibly in combination with the day of the week. This enables to determine traffic hours statistics of the elevators, and based on these statistics to determine proper service and eventual breakdowns of the elevator. In a fourth preferred embodiment of the method according to the invention, said transmission of said signal is realised by generating a mobile phone compatible short message comprising said retrieved signal and transmitting said short message through a mobile phone. This particular embodiment enables to send data, in this case the retrieved signals, while keeping the phone line free for voice communication. The voice communication may be used if someone is trapped in the elevator. For this purpose, the mobile phone is connected to an alarm communication unit provided in the elevator car. In addition, this embodiment presents the important advantage that it is not required anymore, thanks to the use of a mobile phone, for installing the system - 4 - according to this embodiment, to require, in addition to an elevator technician, a technician from a telephone company for installing a telephone line in the machine room of the elevator system.

The present invention further relates to a device for monitoring the operation of an elevator system provided with a safety circuit forming a closed loop, said safety circuit being provided for enabling the operation of the elevator when a current passes through said safety circuit, said device comprising processing means connected to a sensing device provided for retrieving a signal indicative of an event within the elevator, said device further comprising a memory connected within said processing means and provided for storing the retrieved signal, and communication means connected to the memory and provided for transmitting the stored signal to a remote station, characterised in that said sensing device is provided for retrieving said signal from said safety circuit.

According to a preferred embodiment of the device according to the invention, said communication means are connected to an alarm communication unit provided to be fitted in the passenger compartment of the elevator car, said alarm communication unit comprising a loudspeaker, a microphone and an activation button connected to said communication means, whereby said microphone and loudspeaker are enclosed within said activation button, which activation button is provided with perforations, and said activation button is covered by a transparent cover plate provided to be broken in case of activation. This particular embodiment enables to protect the communication unit from dust and obstructions, since the loudspeaker and microphone are only accessible through the perforations when the alarm is activated by breaking the transparent cover plate.

The invention will now be described further in detail referring to the annexed drawings, wherein : - 5 - Figure 1 schematically illustrates an elevator system with the device according to a preferred embodiment of the invention;

Figure 2 shows a communication unit of the device according to the invention provided to be installed in the elevator car; Figure 3 is an exploded view of Figure 2;

Figure 4 illustrates a first histogram showing, for a plurality of runs of the elevator, a number of runs of the elevator in function of the elevator runtime; and

Figure 5 illustrates a second histogram showing, for a plurality of runs of the elevator, a number of runs of the elevator in function of a predetermined time pattern.

Referring to Figure 1 , there is shown a typical traction elevator system comprising an elevator 1 connected to a counterweight 2 and driven by a motor 3 located in the machine room 4. Such as in most of the elevator systems, there is provided a safety circuit 5. The safety circuit 5 forms a closed loop and is provided for enabling the operation of the elevator when a current passes through the safety circuit, i.e. when the circuit is closed. The safety circuit comprises at least a number of door switches 6, 7, 8 wherein said switches are closed when the respective door is closed. In addition to the door switches 6, 7, 8, the safety circuit optionally comprises i.a. the following switches : end switches 9 and 12 for preventing overtravel in the downward and upward position of the elevator car, switch 10 for indicating a closed state of the elevator car door, a manual stop switch 11 and an overspeed governor switch 13. If one of the switches is "open", the loop of the safety circuit will be open, so that no current passes through the safety circuit. Consequently, the elevator can not run.

According to the invention, the elevator system is equipped with a device for monitoring the operation of the elevator. The device according to the invention comprises processing means 14 and is - 6 - provided for retrieving an electrical signal from the safety circuit 5 by means of a sensing device 31 connected to the processing means 14. The electrical signal may be a voltage or preferably a current measurement. Determination of the current is preferably performed without galvanic contact with the safety circuit. This may be achieved by means of a magnetic sensing device, such as a hall sensor 31. The hall sensor 31 is placed, as shown in Figure 1 , adjacent to the safety circuit in order to determine the magnetic field and hence the current therethrough. The current determined by the sensing device 31 is transmitted to the processing means 14. A memory is provided within the processing means 14 and provided for storing the retrieved signal, in particular the current value determined by the sensing device. Communication means 15 are connected to the processing means 14 for transmitting the stored signal to a remote station (not shown). A power supply (not shown) is connected to the processing and communication means.

The communication means comprise a telephone and communication logic for enabling establishing and responding to a call. Preferably, the telephone in the communication means is a mobile phone, hence it is not required to install a telephone land line in the machine room for enabling communication with a remote station. This means that the monitoring system according this preferred embodiment may be installed by an elevator technician without the intervention of a phone company technician. It should be noted that the use of a mobile phone as communication means in an elevator system for sending data and voice could also be used in another elevator system, even an elevator system without a device for monitoring the operation of an elevator car according to the invention.

According to a preferred embodiment, the processing means are provided for converting the stored signals in a short message - 7 - (SMS) compatible message to be sent by the mobile phone. This is for example achieved by converting the values of the counters providing the statistical information of the retrieved signal into an ASCII string satisfying the SMS format, and this according to techniques known as such. The advantage thereof is that the same communication means may be used for sending data and establish a voice communication simultaneously.

The communication means are connected to an alarm communication unit 16. When blocked in the elevator car 1 , the entrapped person may establish a contact with the remote station or possibly another station for obtaining assistance. More details concerning the alarm communication unit 16 will be described further when referring to Figures 2 and 3.

The communication and possibly also the processing means are preferably provided on top of the elevator car, as shown in Figure 1 , instead of the machine room such as in other systems, in order to avoid installation of cables between the elevator car and the machine room.

Figures 2 and 3 show an alarm communication unit 16 according to a preferred embodiment of the present invention. This communication unit 16 comprises a housing 17 provided to be flush mounted to a wall of the elevator car by means of screws 18. The housing 17 is provided for receiving a circuit board 19 comprising a loudspeaker and microphone. Instead of having an activation button and a separate cover grid for the microphone and loudspeaker, such as in the known alarm communication units, the alarm communication unit according to the invention provides for an activation button 22 enclosing the microphone and loudspeaker. For this purpose, the activation button is provided with perforations 25. This renders the construction relatively compact. The circuit board 19 is fixed by means of screw 20. Between - 8 - the activation button 22 and the circuit board 19, there is provided a spring 21 for resiliently pushing the activation button away from the circuit board 19. The activation button 22 is provided for activating a switch on the circuit board 19, which switch is connected to the communication means 15 by cable 24 (Figure 1 ) and provided for activating a voice communication with a remote station. This voice communication activation is known as such and will therefore not be described further in detail. In addition to the advantage of being compact, the alarm communication unit presents the advantage that it is not required to provide a large hole in the elevator car for receiving the unit, such as in known communication units. In contrary, four small perforations for the screws 18 and a small hole for the cables 24 connected to the communication means 15 (Figure 1 ) are sufficient.

Preferably, the alarm communication unit 16 according to the invention further comprises a transparent cover plate 23 which is provided to be broken when a user wants to activate the alarm communication unit. For this purpose, the cover plate is provided for example with lips 26 which will break when someone pushes on the button. This particular embodiment better protects the microphone/loudspeaker from dust and other intrusive objects, such as for example a pen, since the perforations 25 are only accessible when the transparent plate 23 is broken. This transparent plate 23 forms also a kind of psychological barrier for abuse of the unit, since the user first has to break something, i.e. the transparent plate, before activating the unit. It should be noted that the alarm communication unit 16 could also be used in another elevator system, even an elevator system without a device for monitoring the operation of an elevator car according to the invention.

The signal retrieved from the safety circuit of the elevator system may be used for determining histograms as shown in Figures 4 - 9 - and 5. Figure 4 shows an example of a first histogram according to the invention illustrating, for a plurality of runs of the elevator car, the number of runs of the elevator car in function of the elevator runtime. This can easily be achieved by providing the processing means 14 of the monitoring device with a clock for determining the duration of the retrieved signal for each run of the elevator. Assume, for example, that the runtime of the elevator car is 5 seconds per floor. This means that when the elevator car travels during 15 seconds, it will run for 3 floors. By counting during a predetermined period, for example 24 hours, the number of runs for each runtime, the histogram according to Figure 4 is for example obtained. Figure 4 shows thus that the elevator has run 30 times during 5 seconds (corresponding to floor), 20 times during 10 seconds (corresponding to two floors), 15 times during 15 seconds (corresponding to three floors) and 10 times during 20 seconds (corresponding to four floors). This histogram may be sent as data to the remote station. Based on that histogram, useful information can be deduced such as total runtime duration (for maintenance purposes) and failures, such as starting failures (to be deduced from peak 27), stopping accuracy at the floors (to be deduced from peaks 28 and 29) and stopping between two floors (to be deduced from small peak 30).

In Figure 5, there is shown an example of a second histogram according to the invention illustrating, for a plurality of runs of the elevator car, the number of runs of the elevator car in function of the time of the day. This can again easily be achieved by providing the processing means 14 of the monitoring device with a clock for determining the time when the signal is retrieved for each run of the elevator. By accumulating during a predetermined period, for example 1 month, the number of runs in function of a predetermined time pattern, for example the time of the day, possibly in combination with a day of the week, the histogram according to Figure 5 is for example obtained. This - 10 - histogram may be sent as data to the remote station. Based on that histogram, useful statistical information can be deduced such as traffic pattern. Figure 5 shows for example that the elevator is most used between 4 and 6 p.m. (16 and 18 hours) and also between 7:45 and 9:30 a.m. and between 11 a.m. and 12:45 p.m. Based on such statistics, malfunctions may be detected if for example, during a certain period within peak hours, the elevator is not working, for example due to overheating.

- 11 - LIST OF REFERENCES IN THE DRAWINGS

1 elevator car

2 counterweight

3 motor machine room

5 safety circuit to 8 door switches

9 end switch down

10 elevator car door switch

11 manual stop switch

12 end switch up

13 overspeed governor switch

14 processing means with memory

15 communication means

16 alarm communication unit

17 housing

18 screw

19 circuit board with loudspeaker, microphone and switch 0 screw 1 spring 2 activation button 3 cover plate 4 cables 5 perforations 6 lips 7 to 30 failure peak signals

1 sensing device

Claims

- 12 - CLAIMS

1. A method for monitoring the operation of an elevator system provided with a safety circuit forming a closed loop, said safety circuit being provided for enabling the operation of the elevator when a current passes through said safety circuit, said method comprising the steps of : retrieving an electrical signal indicative of an event within the elevator system; storing the retrieved signal; and transmitting the stored signal to a remote station; characterised in that said signal is retrieved from said safety circuit of the elevator system.

2. A method according to claim 1 , wherein said signal is retrieved by determining a current passing through said safety circuit.

3. A method according to claim 2, wherein said current is determined by means of a magnetic sensing device.

4. A method according to claim 3, wherein a hall sensor is used as magnetic sensing device.

5. A method according to any one of the preceding claims, further comprising the step of determining, by means of said signal, a first histogram showing, for a plurality of runs of the elevator, a number of runs of the elevator in function of the elevator runtime.

6. A method according to any one of the preceding claims, further comprising the step of determining, by means of said signal, a second histogram showing, for a plurality of runs of the elevator, a number of runs of the elevator in function of the time of the day.

7. A method according to any one of the preceding claims, wherein said transmission of said signal is realised by generating a mobile phone compatible short message comprising said retrieved signal and transmitting said short message through a mobile phone. - 13 -

8. A device for monitoring the operation of an elevator system provided with a safety circuit forming a closed loop, said safety circuit being provided for enabling the operation of the elevator when a current passes through said safety circuit, said device comprising processing means connected to a sensing device provided for retrieving a signal indicative of an event within the elevator, said device further comprising a memory connected within said processing means and provided for storing the retrieved signal, and communication means connected to the memory and provided for transmitting the stored signal to a remote station, characterised in that said sensing device is provided for retrieving said signal from said safety circuit.

9. A device according to claim 8, wherein said communication means are connected to an alarm communication unit provided to be fitted in the passenger compartment of the elevator car, said alarm communication unit comprising a loudspeaker, a microphone and an activation button connected to said communication means, whereby said microphone and loudspeaker are enclosed within said activation button, which activation button is provided with perforations, and said activation button is covered by a transparent cover plate provided to be broken in case of activation.

10. An elevator car comprising a device according to claim 8 or 9, wherein said communication means are mounted on top of the elevator car.

11. Use of a safety circuit of an elevator system for monitoring the operation of the elevator system, wherein said safety circuit forms a closed loop provided for enabling the operation of the elevator when a current passes through said safety circuit.

12. Use of a mobile phone as communication means in a device for monitoring the operation of an elevator system. - 14 - 13. An alarm communication unit for an elevator car, said communication unit comprising a loudspeaker, a microphone and an activation button and provided to be connected to communication means, characterised in that said microphone and loudspeaker are enclosed within said activation button, which activation button is provided with perforations, and said activation button is covered by a transparent cover plate provided to be broken in case of activation.