Elevator system

Abstract

 The invention relates to an elevator system (10) comprising at least one elevator (12) having an elevator car (14) with at least one car door (22), and an elevator shaft (16) comprising landing doors (32), at least one control unit (34) for controlling the elevator, a safety circuit (50) with a series connection of safety circuit switches (42, 44) which is connected to the control unit, whereby at least one safety circuit switch (42) is assigned to the car door status and at least one safety circuit switch (44) is assigned to a landing door status, and a car position detection device (38, 40), which control unit comprises an operating mode control (60) configured to switch between a first operating mode, wherein the safety circuit is activated and a second operating mode wherein at least one of the safety circuit switches of the safety circuit is bypassed by a bypass means (52). Upon activation of the second operating mode the control unit activates a roof position determination unit (62) which is connected with the car position detection device and/or with a separate roof position detection device, whereby
- the roof position determination unit (62) of the control unit (34) comprises a roof zone indicator (66) which is activated when the car roof (15) is positioned within a certain level range with respect to a landing floor (30), and/or
- the roof position determination unit (62) initiates a car operation stop circuit (63) in the control unit (34) to stop the elevator car (14) when the car roof (15) is positioned within a certain level range with respect to a landing floor (30). Via the invention operating personal is easily able to get access to the car roof in case of malfunction of a safety circuit switch or if he wants access to the car roof with a safety circuit switch open.

Description

[0001] The present invention relates to an elevator system comprising at least one elevator having an elevator car with at least one car door and an elevator shaft comprising landing doors. The elevator system has at least one control unit for controlling the at least one elevator, a safety circuit for each elevator with a series connection of safety circuit switches. The safety circuit is connected to the control unit for enabling a safe operation of the elevator.

[0002] At least one of the safety circuit switches is assigned to the car door status and at least one per se known safety circuit switch is assigned to the status of a landing door, usually as binary value "closed/not closed". Preferably, at least one safety circuit switch is provided for the landing doors of each landing of the elevator. The safety circuit with the safety switches can also be embodied as an electronic safety controller with a safety data bus to which the safety circuit switches are connected.

[0003] Furthermore, the elevator system comprises a car position detection device which is used by the control unit to move the elevator car during normal operation to the correct stop positions aligned with the landings. The control unit further comprises an operating mode control which is configured to switch between a first operating mode and a second operating mode. In the first operating mode is intended for normal elevator use the safety circuit is activated and accordingly all safety circuit switches are monitored. In this first operating mode the disconnection or malfunction of only one safety circuit switch leads to a stop of the elevator car. In the second operating mode at least one of the safety circuit switches of the safety circuit is bypassed by a bypass means. In case the safety circuit is realized by an electronic safety controller the bypass means may also be realized by software implementation, particularly in the control unit or safety controller. This second operating mode is intended as rescue operation mode (RDF) or maintenance mode which allows only assigned persons to move the elevator car. The fact that the elevator car can be moved although one or several of the safety circuit switches are open or malfunction but being bypassed by the bypass means leads to the possibility to move the elevator car with landing/car door open or with safety circuit switches malfunction. Accordingly, in this second operating mode it is possible to free passengers from the elevator car with open or broken safety circuit switches.

[0004] Furthermore, particularly in machine room-less elevators maintenance takes place in the elevator shaft. Thus drive components of the elevator as e.g. the frequency converter, hoisting machine, brake controllers etc. are often disposed in the top of the elevator shaft such that the maintenance has to be performed from the car roof. This requires that first the elevator car has to be positioned in a level that its car roof is on the same level as a landing floor or shaft entrance such that a maintenance person may easily enter the car roof. For this purpose, the elevator car is driven from outside of the shaft with manual rescue drive buttons to the correct level. In this second operating mode, the car moves with low speed, the car runs as long as the rescue drive button is pressed continuously and stops immediately when the button is released. With this arrangement, the positioning of the elevator car is difficult because when the rescue drive buttons are operated from outside of the elevator shaft, the maintenance person doesn't have direct view to the movement of the car. So the correct car position must be somehow estimated and several correction drives are normally required.

[0005] It is therefore object of the present invention to provide an elevator system of the above mentioned type which easily allows access to the elevator car roof.

[0006] This object is solved according to the present invention with the features of claim 1. Preferred embodiments of the invention are subject-matter of the dependent claims. According to the present invention, upon activation of the second operating mode, the control unit activates a roof position determination unit which is connected with the car position detection device and/or with a separate roof position detection device. The roof position determination unit of the control unit comprises a roof zone indicator which is activated when the car roof is positioned within a certain level range with respect to a landing floor or other shaft entrance. The roof position determination unit either uses the data from the car position detection device and data from a database to calculate via the dimensions of the elevator car the level difference from the car bottom to the car roof. Alternatively or additionally, the roof position determination unit might get information from a separate roof position detection device which is used to control the roof zone indicator according to the current position of the car roof in the shaft. The roof zone indicator is usually a lighting signal, e.g. an LED provided at the operating panel or in a separate maintenance operating panel. The zone indicator can also be provided on a mobile device as e.g. a laptop which is used as a terminal in connection with the control unit. The roof zone indicator may also issue acoustic signals alternatively or additionally to a visual signal. Via the invention the levelling of the car roof may not only be controlled with respect to a landing floor but also with any other shaft access, e.g. a machine room door to the shaft or a maintenance hatch in the shaft wall.

[0007] Additionally or alternatively, the roof position determination unit may initiate a car operation stop circuit in the control unit to stop the elevator car when the car roof is positioned within a certain level range with respect to a landing door. In this case the elevator car is automatically stopped as soon as the car roof has reached the certain level range with respect to a landing floor or other shaft access. Usually, this certain level range is the landing door zone, i.e. a certain zone wherein the car door is essentially aligned with the landing floor so that entering the car is possible without danger. Typically, the landing door zone is +/-2 cm with respect to the landing floor. Optionally the correct car roof position may also be indicated by the roof zone indicator. The certain level range may also be selected larger as it is only used by experienced maintenance persons.

[0008] Via this solution, maintenance persons are able to get onto the car roof easily either by moving the elevator car up and down until the car roof reaches a landing floor level, whereafter the roof zone indicator is activated which shows to the maintenance person that the car roof can be entered via a certain landing or shaft entrance or the elevator car is stopped in the correct position to enter the car roof from the landing.

[0009] The invention can be realised with a conventional safety circuit to which several safety circuit switches are connected in series or by an electronic safety controller, which reads the safety circuit switches via a safety data bus. In this case the safety switches are not directly in series connection but are interconnected by means of a data bus, in which case the bypass means may be software implemented.

[0010] The invention is preferably embodied such that the inventive level check with the car roof is only performed with respect to one certain landing, i.e. the uppermost or lowermost landing, where e.g. the control panel is located.

[0011] In a preferred embodiment of the invention, the control unit comprises a re-activation element located in connection with a control unit or maintenance operating panel to initiate the movement of the elevator car after it has stopped with the roof in the certain level range. The re-activation element may be formed by the same push buttons or the like which are used in the control panel or maintenance operating panel or in a separate RDF panel (panel for rescue operation) for moving the elevator car up and down. These buttons are pushed continuously by a service operator until the roof zone indicator indicates the arrival of the car roof in an entrance zone or the elevator is stopped by the car operation stop unit in said zone. This is the indication for the service operator that the car roof is at the right level with the landing or shaft access to enter. Now if service operator however wants to continue running the car from the same panel outside the shaft (for example, if he wants to run it to the floor zone to enter the car), he has to release the button and push it again, whereupon elevator starts to run again. The reactivation element can therefore be formed by known activation elements which have to be operated in a certain way, e.g. being operated again after car has stopped in the roof zone.

[0012] The re-activation element may be realized as one or several push buttons, key switches, activation levers or the like.

[0013] Hereinafter the term "car" is used as synonym to "elevator car" and the term "shaft" is used as synonym to "elevator shaft".

[0014] Usually, current elevator systems have a door zone indicator which is activated as soon as the bottom of the elevator car is located within the landing zone. The roof zone indicator may in an advantageous embodiment of the invention be realized by activating the door zone indicator in a different operating mode than normal, i.e. than it is used for its intended indication of the correct car bottom position with respect to a landing zone. For example, the first indication mode for the door zone may be "continuously lighting" whereas the second indication mode for the roof zone may be "blinking". Of course, the door zone or roof zone indicators can also be provided by acoustic means in which case different acoustic signals can be given for the first and second indication mode. It is also possible to use visual as well as acoustic indication for the roof zone indicator. This embodiment uses an already existing door zone indicator for the indication of a door zone also for the indication of the roof zone. This has the advantage that no separate indicator has to be provided for the roof zone indication in a conventional control panel or maintenance operating panel so that the hardware amendments can be minimized. Thus the invention can be realized easily during the modernisation of an existing elevator system.

[0015] Of course it is also possible to provide a separate roof zone indicator in a control panel of the control unit or in a maintenance operating panel additionally to a door zone indicator.

[0016] Preferably, the roof zone indicator is located in a control panel of the control unit accessible from a landing or from a machine room. Via this measure, the operating person can safely drive the elevator car to a position where its roof is in line with a landing and then can safely enter the car roof from a landing door.

[0017] A preferred embodiment: maintenance / rescue control panel having RDF buttons is normally situated in (lockable) maintenance access electrification panel (MAP) at the landing outside the shaft, for example at the landing door frame. It is usually connected to the elevator control unit via serial communication line. The elevator control unit is preferably in the same MAP. The elevator control unit is further connected to the elevator drive via a second serial communication line, and the drive (frequency converter, brake controllers and hoisting machine) are disposed at the same location in the shaft, remote from the MAP. This way the power lines between frequency converter, brake controller and hoisting machine are substantially short and no unwanted voltage reduction exists in the power cables.

[0018] Of course, the roof zone indicator may also be located in a wireless serviceman's tool which is connectable wirelessly to the control unit. Such a tool can alternatively be provided as software implementation on a laptop or mobile device, e.g. smartphone or the like. In this case the maintenance operator may drive the car to an adapted position for entering the car roof form a remote location.

[0019] Preferably, the roof position determination unit gets the actual car position data via a landing zone detection device which is usually provided in current elevator systems to bring the car bottom in line with the landing floor during normal operation of an elevator system. Via this means, the levelling of a car roof to the landing can be performed using existing hardware from current elevator systems.

[0020] Preferably, the maintenance / rescue control panel comprises a mode switch for changing between the first and second operating mode of the elevator whereby accordingly the bypass means is deactivated (first mode) or activated (second mode). Via this mode switch, it is easily possible for a maintenance operator to change the operating mode of the elevator system between the first and second operating mode in which he can move the elevator car although a landing door and/or the car door is open or a safety circuit switch malfunctions.

[0021] Preferably, the mode switch is arranged at a maintenance / rescue control panel which is in connection to the elevator control unit. Via such a maintenance operating panel, the operating personnel is easily able to operate the elevator car in the second operating mode from an adapted location, preferably from the landing where he intends to enter the car roof. The same holds true for the roof zone indicator. The term "certain level range" means that the car roof is within a certain limited range with respect to the landing floor, e.g. +/-20 cm with respect to the landing floor. Of course, this certain level range can also be the landing door zone which is essentially smaller, e.g. +/-2 cm with respect to the landing floor.

[0022] The roof position determination unit preferably comprises a database or is connected with a database with data comprising the dimensions of the elevator car so that the roof position determination unit is able to calculate the roof position from the data of the car position detection device. Of course, it is also possible to use a separate roof position detection device in which case such connection to database is not necessary for the roof position determination unit.

[0023] Thus it is for example possible to dispose marking pieces (landing zone indication elements) in the shaft such that they may express the door zone. To the car a reader (position detection sensor) is fixed which reads the marking pieces when located at the immediate vicinity of them, thereby getting the information that elevator car is at the door zone. In addition to this, it is possible to add marking pieces to the places wherein they express the roof zone, and these marking pieces can be read with the same reader device (position detection sensor). The marking pieces can be permanent magnets with RFID tags, and the reader can comprise hall sensors in combination with RFID reader, as disclosed in patent application WO 2010/018298 A1.

[0024] Preferably, the control panel of the control unit and/or a maintenance operating panel comprises push buttons for the up and down direction of the elevator car to enable the operating personnel to easily drive the elevator car to a desired position so that the car roof is within the landing zone. Preferably in this case the control panel or maintenance operating panel may be software implemented on a mobile device as a laptop or smartphone. In this case the maintenance operator may drive the car while standing on the car roof, without necessitating separate operating elements on the car roof for the car movement. The hardware effort for the invention is therefore minimized.

[0025] It shall be clarified that inventive embodiments are also discussed in the description and the figures of the present invention. The inventive content may also consist of several separate inventions, especially if the invention is considered in the light of expressions or implicit sub-tasks or from the point of view of advantages or set of advantages achieved. Therefore, some of the attributes contained in the claims below may be unnecessary from the point of view of separate inventive concepts. It shall further be clarified that the features of the different embodiments mentioned above may be combined with each other as long as this is not in technical contradiction.

[0026] The invention is hereinafter described in connection with the schematic drawings. In these

Fig. 1 shows a schematic diagram of an elevator system having an elevator car moving vertically within an elevator shaft between different landings, and

Fig. 2 shows a schematic diagram of essential components of the elevator system for operating the elevator in a second operating mode under bypassing safety circuit switches of the safety circuit.

[0027] Fig. 1 shows an elevator system 10 comprising an elevator 12 having an elevator car 14 moving in an elevator shaft 16 up and down via the action of a drive unit 18 and its brakes 20. The connection between the drive unit 18 and the car 14 is realized via hoisting ropes which are not shown in the drawing for clarity reasons. The elevator car comprises a car roof 15, a car bottom 17 and a car door 22. The elevator shaft 16 is connected to landings 24, 26, 28 each having a landing floor 30, which landings are connected to the elevator shaft 16 via landing doors 32. In the lowest floor 28, a control unit 34 is provided comprising a control panel 36 which is shown in greater detail in Fig. 2. The elevator car 14 further comprises a car position detection sensor 38 which co-acts with landing zone elements 40 in the area of the landing floor levels of the shaft 16. From the co-action of the car detection sensor 38 with the landing zone elements 40, the elevator system gets the exact position of the elevator car with respect to the landings 24 to 28 for stopping the car in alignment with the landing floors 30.

[0028] It is clear that for the sake of clarity only one elevator and only three landings are shown whereas it is clear that the elevator system may comprise several elevators and that the number of the landings is arbitrary.

[0029] Furthermore, in connection with the car door 22, a car door safety circuit switch 42 is provided and in connection with the landing doors 32, landing door safety circuit switches 44 are provided. These safety circuit switches 42, 44 are part of the elevator's safety circuit and are connected in series with other safety circuit switches being allocated to other components of the elevator as for example elevator motor, elevator brakes, control unit, and the like.

[0030] Fig. 2 shows the control unit 34 together with its control panel 36 in greater detail. The control unit 34 is connected preferably via serial bus to a shaft control unit part 35 located in the shaft comprising the frequency converter for a drive unit 18 as well as the brake controller for two independent drive unit brakes 20. The shaft control unit part 35 is preferably located near the drive unit, whereas the control unit 34 and the control panel 36 are preferably located at a landing, preferably the lowest or uppermost landing. All electric connections are indicated by lines. Furthermore, the control unit 34 is connected to a safety circuit 50 of the elevator 12 which comprises a series connection of electric safety circuit switches 42, 44 from which the drawing only shows two landing door switches 44 and one car door switch 42. Another (equivalent) embodiment would be to the use of an electronic safety controller, which reads safety circuit switches via a safety data bus. In this case the safety switches are not in series connection but are interconnected by means of a data bus.

[0031] The control unit 34 is also connected to a bypass means 52 which comprises at least one, preferably several controllable bypass switches 54, 56 via which the safety circuit switches 42, 44 of the safety circuit 50 can be bypassed. Furthermore, the control unit 34 is connected to the car position sensor 38 located in the elevator car 14. The control unit 34 comprises as hardware modules or as software implementations an operating mode control 60, as well as a roof position determination unit 62, a database 65 with car dimension data as well as a calculating unit 63. The control panel 36 comprises additionally to usual components of an elevator control panel (which are not shown for clarity reasons) an operating mode switch 64 a door zone indicator LED 66 as well as push buttons 68, 70 for the up- and downward movement of the elevator car. This inventive elevator system works as follows:

[0032] A maintenance operator or other admitted person opens a lockable cover of the control panel 36 which is located at a landing28 of the building aside of a landing door 32. Via the operating mode switch 64 the maintenance operator switches the elevator control to the second operating mode in which the bypass means 52 is activated as to bypass the safety circuit switches 42, 44 for the car door and the landing doors via the bypass switches 54 and 56. This allows the maintenance operator to move the elevator car although one or several of the safety circuit switches of the car door or the landing doors are open or malfunction. After having entered the second operating mode, the maintenance operator can push the up or down button 68, 70 to move the elevator car with a low speed in the corresponding direction. Thereby, he can monitor the position of the elevator car via the door zone indication LED 66 which continuously is activated as long as the car bottom is in the landing zone and which blinks as soon as the car roof is within the landing zone. After that, the operating personnel releases the corresponding push button 68, 70 whereafter the elevator car immediately stops. Now the maintenance operator can manually open the corresponding landing floor and enter the car roof and perform maintenance work in the elevator shaft.

[0033] Additionally, the operating personnel may have a control panel similar to the shown control panel 36 on a mobile device, e.g. a laptop or a smartphone so that he is able to move the elevator car up and down while standing on the car roof so as to drive in different zones of the elevator shaft to perform maintenance work. This control panel may be realized by an additional inspection drive box with inspection drive buttons in car roof which the maintenance worker could use.

[0034] After having finished his work, he can optionally travel back to the landing where he has entered the car roof, close the landing door and switch the operating mode switch 64 so as to turn the control unit back to the first operation mode wherein the elevator system works normally whereby safety circuit switches 42, 44 of the safety circuit 50 are closed and are monitored via the control panel.

[0035] It shall be clear that the features of the different embodiments may be combined arbitrarily as long as this is technically possible. Furthermore, single components mentioned above, e.g. all components which are provided in connection with the control unit, may be provided as a single unit or several units or may be distributed over different locations. Furthermore, the control unit may be the control unit of a single elevator or of an elevator group or elevator multi-group.

[0036] The invention can be carried out within the scope of the appended patent claims.

Claims

1. Elevator system (10) comprising at least one elevator (12) having an elevator car (14) with at least one car door (22), and an elevator shaft (16) comprising landing doors (32), at least one control unit (34) for controlling the elevator, a safety circuit (50) to which one or more safety circuit switches (42, 44) are connected, which safety circuit is connected to the control unit, whereby at least one safety circuit switch (42) is assigned to the car door status and at least one safety circuit switch (44) is assigned to a landing door status, and a car position detection device (38, 40), which control unit comprises an operating mode control (60) configured to switch between a first operating mode, wherein the safety circuit is activated and a second operating mode wherein at least one of the safety circuit switches of the safety circuit is bypassed by a bypass means (52), characterized in that upon activation of the second operating mode the control unit activates a roof position determination unit (62) which is connected with the car position detection (38, 40) device and/or with a separate roof position detection device, and

- that the roof position determination unit (62) of the control unit (34) comprises a roof zone indicator (66) which is activated when the car roof (15) is positioned within a certain level range with respect to a landing floor (30) or other shaft access, and/or

- that the roof position determination unit (62) initiates a car operation stop circuit (63) in the control unit (34) to stop the elevator car (14) when the car roof (15) is positioned within a certain level range with respect to a landing floor (30) or other shaft access.

2. Elevator system according to claim 1, characterized in that the control unit (34) comprises a re-activation element (68, 70) located in connection with a control panel (36) the control unit or a maintenance operating panel outside the elevator shaft to initiate further movement of the elevator car (14) after it has stopped with its roof (15) within the certain level range.

3. Elevator system according to claim 2, characterized in that the re-activation element is a push button (68, 70) or operating mode switch.

4. Elevator system according to one of claims 1 to 3, characterized in that the roof zone indicator (66) is a door zone indicator which is activated in a first indication mode when the car bottom is in a certain level range with respect to a landing door and which is activated in a second indication mode when the car roof is in a certain level range with respect to a landing door.

5. Elevator system according to claim 4, characterized in that the first indication mode is continuous lighting and the second indication mode is blinking.

6. Elevator system according to one of claims 1 to 3, characterized in that the door roof indicator is a separate indicator in the control unit or maintenance operating panel additionally to a door zone indicator.

7. Elevator system according to one of the preceding claims, characterized in that the roof zone indicator (66) is located in a control panel (36) of the control unit (34) accessible from a landing (24, 26, 28) or from a machine room.

8. Elevator system according to one of the preceding claims, characterized in that the roof zone indicator is located in a maintenance access panel connectable to the control unit in a location remote from the elevator shaft.

9. Elevator system according to one of the preceding claims, characterized in that the roof position determination unit (62) gets the car position data under use a landing zone indication elements (40) of the elevator (12).

10. Elevator system according to one of the preceding claims, characterized in that the control unit (34) comprises a mode switch (64) for changing between the first and second operating mode of the elevator (12), whereby the bypass means (52) is activated/deactivated.

11. Elevator system according to claim 10, characterized in that the mode switch (64) is arranged at a maintenance operating panel which is in remote connection to the control unit.

12. Elevator system according to one of the preceding claims, characterized in that the roof zone indicator (66) is arranged at a maintenance operating panel which is in remote connection to the control unit (34).

13. Elevator system according to claim 11 or 12, characterized in that the maintenance operating panel is provided on a mobile computing device.

14. Elevator system according to one of the preceding claims, characterized in that the certain level range is the landing door zone.

15. Elevator system according to one of the preceding claims, characterized in that the roof position determination unit (62) is connected with a database (65) comprising dimension data of the elevator car and is connected to a calculating unit of the control unit to derive from the car position detection device (38, 40) the position of the car roof (15) with respect to a landing floor (30) of the elevator shaft (16).

16. Elevator system according to one of the preceding claims, characterized the control unit (34) is connected with a separate roof position detection device which is arranged additionally to the car position detection device.

Amended claims

Amended claims in accordance with Rule 137(2) EPC.

1. Elevator system (10) comprising at least one elevator (12) having an elevator car (14) with at least one car door (22), and an elevator shaft (16) comprising landing doors (32), at least one control unit (34) for controlling the elevator, a safety circuit (50) to which one or more safety circuit switches (42, 44) are connected, which safety circuit is connected to the control unit, whereby at least one safety circuit switch (42) is assigned to the car door status and at least one safety circuit switch (44) is assigned to a landing door status, and a car position detection device (38, 40), which control unit comprises an operating mode control (60) configured to switch between a first operating mode, wherein the safety circuit is activated and a second operating mode wherein at least one of the safety circuit switches of the safety circuit is bypassed by a bypass means (52), wherein upon activation of the second operating mode the control unit activates a roof position determination unit (62) which is connected with the car position detection (38, 40) device and/or with a separate roof position detection device, and

- that the roof position determination unit (62) of the control unit (34) comprises a roof zone indicator (66) which is activated when the car roof (15) is positioned within a certain level range with respect to a landing floor (30) or other shaft access, and/or

- that the roof position determination unit (62) initiates a car operation stop circuit (63) in the control unit (34) to stop the elevator car (14) when the car roof (15) is positioned within a certain level range with respect to a landing floor (30) or other shaft access,
characterized in that the roof position determination unit (62) is connected with the car position detection (38, 40) device and/or with a separate roof position detection device, and that the roof zone indicator (66) is a door zone indicator which is activated in a first indication mode when the car bottom is in a certain level range with respect to a landing door and which is activated in a second indication mode when the car roof is in a certain level range with respect to a landing door.

2. Elevator system according to claim 1, characterized in that the control unit (34) comprises a re-activation element (68, 70) located in connection with a control panel (36) the control unit or a maintenance operating panel outside the elevator shaft to initiate further movement of the elevator car (14) after it has stopped with its roof (15) within the certain level range.

3. Elevator system according to claim 2, characterized in that the re-activation element is a push button (68, 70) or operating mode switch.

4. Elevator system according to one of the preceding claims, characterized in that the first indication mode is continuous lighting and the second indication mode is blinking.

5. Elevator system according to one of the preceding claims, characterized in that the roof zone indicator (66) is located in a control panel (36) of the control unit (34) accessible from a landing (24, 26, 28) or from a machine room.

6. Elevator system according to one of the preceding claims, characterized in that the roof zone indicator is located in a maintenance access panel connectable to the control unit in a location remote from the elevator shaft.

7. Elevator system according to one of the preceding claims, characterized in that the roof position determination unit (62) gets the car position data under use a landing zone indication elements (40) of the elevator (12).

8. Elevator system according to one of the preceding claims, characterized in that the control unit (34) comprises a mode switch (64) for changing between the first and second operating mode of the elevator (12), whereby the bypass means (52) is activated/deactivated.

9. Elevator system according to claim 8, characterized in that the mode switch (64) is arranged at a maintenance operating panel which is in remote connection to the control unit.

10. Elevator system according to one of the preceding claims, characterized in that the roof zone indicator (66) is arranged at a maintenance operating panel which is in remote connection to the control unit (34).

11. Elevator system according to claim 9 or 10, characterized in that the maintenance operating panel is provided on a mobile computing device.

12. Elevator system according to one of the preceding claims, characterized in that the certain level range is the landing door zone.

13. Elevator system according to one of the preceding claims, characterized in that the roof position determination unit (62) is connected with a database (65) comprising dimension data of the elevator car and is connected to a calculating unit of the control unit to derive from the car position detection device (38, 40) the position of the car roof (15) with respect to a landing floor (30) of the elevator shaft (16).

14. Elevator system according to one of the preceding claims, characterized the control unit (34) is connected with a separate roof position detection device which is arranged additionally to the car position detection device.

Drawing