METHOD AND ARRANGEMENT FOR DETERMINING ELEVATOR DATA BASED ON THE POSITION OF AN ELEVATOR CAR

Abstract

A method and an arrangement for determining elevator data based on the position of an elevator car of an elevator system includes the elevator car having a flag reading sensor, the elevator car being movably arranged in a hoistway and can be moved by a drive with a suspension rope over a traction sheave, and the elevator car can be stopped at a plurality of stopping positions of the hoistway. Each stopping position has a flag marker with a flag height. Movement of the elevator car is determined by a control unit connected to an encoder at the traction sheave. When leaving a stopping position, the travelled distance of the elevator car between the stopping position and a flag edge is measured and a stopping inaccuracy is determined by the control unit.

Claims

1-15. (canceled)

16. A method for determining elevator data based on a position of an elevator car of an elevator system, wherein the elevator car has a door zone sensor and is movably arranged in a hoistway, wherein the elevator car is moved by a drive with a traction sheave via a suspension means connected to the elevator car and can be stopped at a plurality of stopping positions of the hoistway, each stopping position having a door zone marker with a given height, and wherein movement of the elevator car is determined by a control unit connected to the drive and to an encoder at the traction sheave, comprising the steps of: when the elevator car is leaving one of the stopping positions, a travelled distance of the elevator car between the one stopping position and an edge of the door zone marker at the one stopping position is measured by the control unit using the door zone sensor and the encoder; an actual position parameter based on the travelled distance and the given height of the door zone marker at the one stopping position is determined by the control unit; and the control unit controls the movement of the elevator car in response to the actual position parameter.

17. The method according to claim 16 wherein the actual position parameter is a stopping inaccuracy that is determined by the control unit as an absolute value of a difference between half of the given height and the travelled distance.

18. The method according to claim 17 wherein the stopping inaccuracy is taken into account by the control unit when controlling a next stop of the elevator car.

19. The method according to claim 17 wherein for the one stopping position at least one of a plurality of the travelled distance and a plurality of the stopping inaccuracy over time are stored in a storage connected to the control unit and are used by the control unit to determine a drift or slippage of the elevator car.

20. The method according to claim 19 wherein at least one of the travelled distance and the stopping inaccuracy of the elevator car is determined and stored for each of the plurality of the stopping positions.

21. The method according to claim 19 wherein at least one of the travelled distance and the stopping inaccuracy of the elevator car is determined and stored for each direction of travel of the elevator car.

22. The method according to claim 17 wherein at least one of the travelled distance and the stopping inaccuracy of the elevator car is only determined if a load of the elevator car determined by a load sensor is within a given range.

23. The method according to claim 17 wherein for determining a drifting of the elevator car at least one of the travelled distance and the stopping inaccuracy of the elevator car is only determined if a trip of the elevator car takes place within a given time interval.

24. The method according to claim 17 wherein for determining a slippage of the elevator car at least one of the travelled distance and the stopping inaccuracy of the elevator car is only determined if a trip of the elevator car takes place after a given time interval.

25. An elevator system for performing the method according to claim 16 comprising the elevator car, the door zone, the hoistway, the drive with the traction sheave and the suspension means connected to the elevator car, the plurality of stopping positions of the hoistway, each of the stopping positions having the door zone marker with the given height, and the control unit connected to the drive and to an encoder at the traction sheave.

26. An arrangement for determining elevator data based on a position of an elevator car being movable in a hoistway by a drive, comprising: a door zone sensor on the elevator car; a door zone marker with a given height at a stopping position of the elevator car within the hoistway; means for measuring movements of the elevator car in the hoistway; and a control unit connected to the drive for controlling the movement of the elevator car, the control unit being connected to the means for measuring movements and the door zone sensor for determining a travelled distance of the elevator car between the stopping position and an edge of the door zone marker when the elevator car is leaving the stopping position and for determining a stopping inaccuracy based on the travelled distance and the given height of the door zone marker.

27. The arrangement according to claim 26 wherein the control unit determines the stopping inaccuracy as an absolute value of a difference between half of the given height and the travelled distance.

28. The arrangement according to claim 26 including a storage connected to the control unit for storing the determined stopping inaccuracy.

29. The arrangement according to claim 26 including a load sensor connected to the control unit for measuring a load of the elevator car.

30. The arrangement according to claim 26 wherein the means for measuring movements of the elevator car is a rotary encoder coupled to a traction sheave of the drive.

31. An elevator system including the elevator car, the hoistway, the drive and the arrangement according to claim 26 further comprising at least another stopping position within the hoistway, another door zone marker with the given height at the another stopping position, and wherein the control unit determines another travelled distance between the another stopping position and an edge of the another door zone marker when the elevator car is leaving the another stopping position and determines another stopping inaccuracy based upon the another travelled distance and the given height of the another door zone marker.

Description

DESCRIPTION OF THE DRAWINGS

[0030] Further advantages of the invention will be better understood with the aid of the following description together with the Figures. It is shown in:

[0031] FIG. 1 a schematic view of an elevator system;

[0032] FIG. 1A a detailed view of the detail A of FIG. 1;

[0033] FIG. 2 a schematic view of the detail A of FIG. 1.

DETAILED DESCRIPTION

[0034] In FIG. 1 an elevator system 1 with a hoistway 2 is shown. An elevator car 3 and a counterweight 4 are movably arranged in the hoistway 2 and connected to each other by means of a suspension means, in this case a steel rope 5. The steel rope 5 is conducted over a pulley 6 and a traction sheave 9 connected to an electric motor 8. The traction sheave 9 has an incremental rotary encoder 12 connected to it in order to detect movement of the traction sheave 9 and therefore movement and direction of travel of the elevator car 3.

[0035] A control unit 10 is also present and is connected amongst others with the electric motor 8 and the incremental rotary encoder 12. A data connection 17 allows remote connection and/or diagnosis of the elevator system 1.

[0036] Each floor 7, 7′ and 7″ of the hoistway 2 has a building floor 18, which corresponds to a stopping position of the elevator car 3. Accordingly, a car floor 3.1 of the elevator car 3 is aligned with the respective building floor 18 when the elevator car 3 is standing still at a floor 7, 7′ or 7″. In FIG. 1, the elevator car 3 has stopped at floor 7′.

[0037] In order to correctly stop the car at the desired floor 7′, every building floor 18 is marked with a flag marker 13 with a flag height F. However, it would also be conceivable to use other door zone markers or other markers in the hoistway. The elevator car 3 has a flag reading sensor 15 as a preferred example of a door zone sensor. Flag marker 13 and flag reading sensor 15 are arranged with respect to each other such that when the building floor 18 and the car floor 3.1 are perfectly aligned, this means that building floor 18 and car floor 3.1 are at the same height, the flag reading sensor is positioned exactly in the middle of the flag marker 13. In other words, the distance between the flag reading sensor 15 and a flag edge 14, in this case the lower flag edge, is exactly half of the height F of the flag marker 13.

[0038] When an elevator car 3 is moving to the desired floor 7′, e.g. moving upwards, the control unit 10 can estimate the position of the elevator car by means of the incremental rotary encoder 12.

[0039] In addition, the flag reading sensor 15 may be used when passing a flag marker 13 to correct or increase the precision of the data from the rotary encoder 12.

[0040] When arriving at the desired floor 7′, the flag reading sensor 15 detects the flag edge 14 and sends a signal to the control unit 10. The control unit 10 uses the rotary encoder 12 and the drive 8 to move the elevator car 3 for a further travel of half the height F of the flag marker 13 (F/2), such that the flag reading sensor 15 is exactly positioned in the middle of the flag marker 13 and the building floor 18 and the car floor 3.1 are aligned with each other.

[0041] It is however possible that due to slipping or stretching of the steel rope 5 or due to wrong speed of the elevator car 3, that stopping does not occur at the desired stopping position. Such a case is schematically shown in FIG. 2.

[0042] The control unit 10 can determine this stopping inaccuracy in an indirect way when moving the car for a further ride.

[0043] If the elevator car 3 is moved upward within a given time gap t from the last ride, and the load L of the elevator car 3, measured by means of a load sensor 11, is within a given range L±x, the travelled distance D from start until the detected end of the flag marker 13 (in this case the upper flag edge) is measured by means of the rotary encoder 12. A stopping inaccuracy I is then determined according to I=(F/2−D). Taking into account the direction of travel of the elevator car 3, the control unit 10 can therefore determine if the car was positioned correctly during the last stop or if a step (upward or downward) was present between the building floor 18 and the car floor 3.1. In the configuration shown in FIG. 2, the car floor 3.1 would be higher than the building floor 7.

[0044] The determined stopping inaccuracy I is then used to correct a distance/speed profile used to control the elevator car in order to increase the stopping precision of the elevator car 3.

[0045] The determined stopping inaccuracy is preferably stored in a storage 16 of the control unit 10 and also used to determine if stopping inaccuracy of the elevator system 1 is increasing over time and thus detect a drift of the elevator car 3. The detected drifting may be then compared with a maximal drifting threshold, whereby if the detected drift is above the threshold, an alarm for a technician requesting inspection or the like may be generated, and sent to a maintenance center over the data connection 17. For determining a slippage only values for the travelled distance D and/or the stopping inaccuracy I of the elevator car 3 if an elevator car ride takes place exceeds a given time interval t two trips are separated by a long standstill time are used or taken into consideration for the determination of the slippage. This long time interval t can be 2 hours, preferably 4 hours or most preferably 6 hours (e.g. night sleep of the car).

[0046] In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.