Elevator car, elevator installation, method for operating an elevator system and door drive

Abstract

An elevator car includes at least one elevator door, a door drive for actuating the elevator door, a sensor for detecting the motor power of the door drive and an evaluating unit that determines, based on the motor power detected, whether there is a deviation in the drive force actuating the elevator door from a reference drive force. The evaluating unit determines whether a deviation occurs due to an obstacle in contact with the elevator door or due to altered external conditions, particularly due to altered pressure conditions and/or air flow.

Claims

1. An elevator installation including an elevator car, an elevator door and a door drive for actuating the elevator door, the door drive comprising: a sensor detecting a drive force of the door drive when the door drive is actuating the elevator door of the elevator installation; a sensor unit detecting at least one external condition influencing actuation of the elevator door by the door drive, the sensor unit being arranged inside or outside an elevator shaft in which the elevator car moves; an evaluation unit determining whether the detected drive force deviates from a reference drive force, wherein the reference drive force was previously determined by the evaluation unit from a reference measurement carried out by the sensor and depends on a floor of the elevator installation at which the elevator door is positioned during the actuation; and wherein the evaluation unit accounts for the detected at least one external condition when determining the reference drive force, and when there is a change in the at least one external condition, the evaluation unit determines whether the detected drive force deviates using for the reference drive force either a corresponding other reference drive force that was previously stored or a reference drive force redetermined by the evaluation unit.

2. The elevator installation according to claim 1 wherein the sensor detects the drive force of the door drive by measuring a motor current of the door drive.

3. The elevator installation according to claim 1 wherein the sensor unit detects the at least one external condition as one of pressure conditions, temperature conditions, air flows and wind.

4. The elevator installation according to claim 1 wherein the evaluation unit determines whether the detected drive force deviates by exceeding the reference drive force.

5. The elevator installation according to claim 1 including an adjustment unit as a part of the door drive or as part of an elevator controller for the elevator installation, and wherein at least one of the evaluation unit and the adjustment unit triggers a stop or a reversing movement of the elevator door when the detected drive force exceeds the reference drive force.

6. The elevator installation according to claim 1 wherein the sensor unit is fixed to the elevator car.

7. The elevator installation according to claim 1 wherein the sensor unit is fixed in the elevator shaft.

8. The elevator installation according to claim 1 wherein the elevator installation has a plurality of floors and the evaluation unit determines the reference drive force for each of the floors by: measuring a drive force over at least one of a closing time and an opening time of the elevator door at each of the floors; and accounting for the at least one external condition detected by the sensor unit when the elevator door is at each of the floors.

9. The elevator installation according to claim 1 wherein the evaluation unit determines whether an obstacle is in contact with the elevator door when the door drive is actuating the elevator door.

10. The elevator installation according to claim 1 wherein the evaluation unit uses either the drive force detected for the elevator door positioned at a floor of the elevator installation or the reference drive force for the floor, and further uses the at least one external condition detected by the sensor unit to calculate the reference drive force for at least one other floor of the elevator installation.

11. The elevator installation according to claim 1 wherein the evaluation unit stores the reference drive force for each floor of the elevator installation.

12. The elevator installation according to claim 11 wherein the reference drive force is a reference drive curve or a value.

13. A method for operating an elevator installation, the elevator installation including an elevator car, an elevator door and a door drive for actuating the elevator door, the method comprising the steps of: detecting with a sensor a drive force of the door drive actuating the elevator door; detecting with a sensor unit an external condition influencing the actuating of the elevator door, the sensor unit being arranged inside or outside an elevator shaft in which the elevator car moves; determining a reference drive force per each floor of the elevator installation based upon at least one reference measurement of the drive force and the detected external condition; and when there is a change in the external condition, using for the reference drive force either another reference drive force that was previously stored or a redetermined reference drive force based upon the changed external condition.

14. The method according to claim 13 including determining the reference drive force per each floor over at least one of a closing time and opening time of the elevator door at each of the floors.

15. The method according to claim 13 including the steps of: measuring the drive force using the sensor for at least one of opening and closing the elevator door during a normal operation of the elevator installation; and comparing the measured drive force with the reference drive force to determine whether there is a deviation.

16. The method according to claim 15 including measuring the drive force based upon a motor current of the door drive.

17. The method according to claim 15 including stopping or reversing movement of the elevator door when the measured drive force exceeds the reference drive force.

18. A door drive for actuating an elevator door, the door drive comprising: a sensor detecting a drive force of the door drive when actuating the elevator door; an evaluation unit determining whether the detected drive force deviates from a reference drive force; and wherein the evaluation unit determines the reference drive force for each floor of an elevator installation at which the elevator door is actuated from at least one reference measurement of the drive force over at least one of a closing time and an opening time of the elevator door, and when there is a change in external conditions, the evaluation unit uses for the reference drive force either a corresponding other reference drive force that is already stored or a redetermined reference drive force.

Description

DESCRIPTION OF THE DRAWINGS

(1) The invention is explained below with reference to examples shown in the drawings. In the drawings:

(2) FIG. 1: is a schematic view of an elevator installation;

(3) FIG. 2: is a schematic view of the chimney effect; and

(4) FIG. 3: is an exemplary graph in which, for two floors, the motor current is plotted as a measure for the drive force against time.

DETAILED DESCRIPTION

(5) FIG. 1 is a schematic view of an elevator installation 10. The elevator installation 10 comprises an elevator shaft 12 and an elevator car 1.

(6) The elevator car 1 comprises a car door 13 having two door leaves 2, it being possible to couple the car door 13 to one of a plurality of shaft doors 14 at a given point in time. One of these shaft doors 14 is arranged at each floor 15. As shown in FIG. 1, an elevator door consists of the car door 13 and the lower shaft door 14 coupled to the car door 13.

(7) The elevator car 1 has a door drive 3 for actuating the car door 13 and the shaft door 14 coupled to the car door 13. The elevator car 1 also has a sensor 4 for detecting the motor power of the door drive 3, and an evaluation unit 5. The evaluation unit 5 makes it possible to determine whether a detected maximum drive force 6a, 6b (see for example FIG. 3) deviates from a floor-dependent reference drive force 7a, 7b (see for example FIG. 3).

(8) Since the reference drive force 7a, 7b is dependent on the floor, it can be reliably decided whether there is an obstacle present that is in contact with the elevator door.

(9) The elevator car 1 comprises an adjustment unit 8. If the measured drive force 6a, 6b deviates from the reference drive force 7a, 7b, the adjustment unit 8 triggers a stopping or reversing movement of the elevator door.

(10) The elevator car 1 comprises a sensor unit 9 for measuring pressure conditions, temperature conditions, air flows and/or wind. Alternatively or additionally, a sensor unit 11 for detecting external conditions, in particular pressure conditions, temperature conditions, air flows and/or wind, can be arranged on the elevator shaft 12. This means that the sensor unit 11 can optionally be arranged outside the elevator shaft 12, and the measured values obtained by the sensor unit 11 are taken into account when determining the at least one reference drive force 7a, 7b.

(11) An effect of the chimney effect is shown schematically in FIG. 2. Since the elevator shaft 12 is typically in contact with the environment via the building doors and the elevator doors, warm air can penetrate into the shaft. This warm air rises up, which means that the elevator car 1 experiences a lower pressure in the lower region of the elevator shaft 12 than in the upper region of the elevator shaft 12.

(12) FIG. 3 shows an exemplary graph in which, for two floors, the motor current I is plotted as a measure for the drive force 6a, 6b against the time t, in this case against the length of the door closing time 16.

(13) The solid line corresponds to the drive force 6a on a middle floor. The dashed line corresponds to the drive force 6b on an upper floor where the chimney effect comes into play.

(14) A reference drive force 7a, 7b can be determined, for each of the two floors, from the temporal behavior of the drive force 6a using the maximum value in terms of amount. The reference drive force can be determined, for example, by multiplying the amount of the maximum by, for example, 1.1 or 1.2.

(15) The reference drive forces for the remaining floors can be determined in further measurements or can be extrapolated from these values 7a, 7b.

(16) In regular operation, the elevator door is only stopped or a reversing movement is only initiated when the drive force exceeds the reference drive force for the relevant floor.

(17) Alternatively, the reference drive force can also be stored as a pattern of the drive force behavior over time. A stopping or a reversing movement takes place if the curves deviate. For this purpose, a standard for characterizing the deviation and a corresponding limit value are defined. When making a decision about the deviation of the curve pattern, soft obstacles can also be taken into account.

(18) In addition, values for external conditions, in particular for pressure conditions, temperature conditions, air flows and/or wind, can be detected, using which values the reference drive forces of the respective floors are weighted in order to adapt the reference drive forces to changed external conditions without new measurements of the drive forces.

(19) 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.