WO1995003243A1 - Method for using a security device for lifts - Google Patents

Abstract

Method for using a security device for a lift of the type employing a car driven by an electric motor (1), wherein said security device uses one or more electric batteries (2) during a power failure. The method utilizes a central processing unit (3) integral with the security device to perform: frequency scanning on the electric power supply to the electric motor (1) to identify the precise, suitable frequency generating the highest and most stable current from the electric battery (2) supplying emergency power to the motor (1) and; storage in memory of the optimal working point of the electric motor (1), computed on the basis of data received, following scanning, which correspond to the highest and most stable current. This method is applicable to lifts.

Description

"Method of using a safety device for elevators"

The present invention relates to a safety device capable of equipping elevators. In the event of an incident, a general power outage, power supply to the control panel, or power outage to the brake, the elevator may be stuck between two floors. In order to be released, users must then use a bell or an ^" intercom ^" to warn the guards, the personnel assigned to the maintenance of the elevators or the firefighters.

These interventions are not immediate, so it is common for users to get stuck in the elevator for longer or shorter periods of time, which can reach several hours, or even the day, in some cases. The present invention protects users against this type of breakdown by means of a method and its automatic and fully autonomous device which bring the elevator car upstairs by choosing the direction of travel. more favorable towards the counterweight. The state of the art can be defined by numerous documents.

Among the most interesting, the document WO-A-87/07587 relates to a safety device for an elevator car suspended from lifting cables which actuates the drum of a winch driven by a main electric motor, which has a flywheel. This safety device is remarkable in that an electromagnetic disc is positioned in front of the flywheel without touching it.

In this embodiment, the operation of the elevator is ensured by an electromagnetic disc controlled by an auxiliary motor which is magnetized on the flywheel of the winch in the event of a breakdown.

The document ϋS-A-3.902.573 relates to an emergency control system for an elevator which is implemented automatically as soon as a power failure in low voltage conditions, a phase loss or the like in order to bring the car from the elevator to a predetermined floor and then open or keep the cabin doors open for the time necessary for passengers to exit the elevator. For this, the system includes a battery maintained in charge when the elevator is in normal operating condition. In the event of an electrical problem, the system automatically switches the power supplied by the battery to appropriate controls present in the elevator control system, so that the elevator car automatically moves to a predetermined floor where the passengers will be released as described above.

This system is mainly applied to a hydraulic lift; it allows lowering to the lower floor by simply supplying the hydraulic circuit lowering valve. When the system is applied to an electric lift, it operates at a fixed frequency without automatic optimization of the motor supply frequency.

Document WO-A-88/06817 proposes a control system for an electric motor which comprises a detector, cooperating with an energy absorbing circuit, for controlling and detecting abnormal operating conditions. The control circuit is sensitive to the detection of an anomaly in the energy absorbing circuit to control an integrated safety inverter.

This device makes it possible to control the drift of the elevator winch. Thus, it makes it possible to measure the energy consumed or supplied by the motor during the acceleration and deceleration phases. If the motor starts to drift, the device controls the strength of the three-phase signal transmitted to the motor via the inverter. If the energy absorbing circuit is crossed by too much current, a fuse is destroyed. Following this phenomenon, the central unit then performs an emergency maneuver, which is normal since the engine is supposed to drift. But this maneuver is only possible if the inverter is supplied with DC voltage by the rectifier, itself supplied by the three-phase signal from the network. It is then obvious that if the three-phase network cuts out, the energy absorbing circuit is no longer supplied, the central unit considers that the motor is drifting and performs an emergency maneuver in order to control the speed of the motor. However, since the inverter is no longer supplied with DC voltage, it is impossible for it to control the motor and the elevator is blocked.

This system operates continuously in the presence of mains voltage in order to control the speed of the motor. It is not a safety system in the event of a power failure, because in this case, it is impossible for him to control the winch. Document GB-A-2.194.360 relates to a position detector of the cabin of a hydraulic elevator; this measuring the duration of a power outage, the variations in the position of the lift car going up and down during the power outage are calculated and the position of the car, which was detected just after the power outage sector, is corrected. During normal operations, a random access memory counts pulses from a generator, ^'to determine the cage position. If a fault occurs, a battery supply circuit generates and counts pulses during the fault and at the end of the fault, the random access memory calculates a position correction during the measured time.

This device works on a hydraulic elevator and uses a microprocessor in order to identify the position where it must bring the car after the failure. The engine controls the hydraulic system pump, not a winch that moves a cabin.

At the cutting edge of technology, the present invention is entirely managed by computer or central unit, which makes the security device very reliable. It is powered by batteries maintained in charge. It returns to service as soon as an electrical fault is detected. The central unit automatically sets the optimum operating point for the elevator, without any manual adjustment.

The term optimal operating point for an engine electric elevator, a speed of movement such that the torque is very high and very stable so as to avoid jolts during the maneuver.

The safety device adapts to the type of engine and generates the electrical signal necessary for operating the winch, brings the cabin upstairs by detecting the position of said cabin, then opens the doors in order to free the occupants. By digital and analog conversion methods, the central unit monitors the signals from the interfaces, in order to stabilize the operating point.

To this end, the present invention provides a method of using a safety device for an elevator of the type using a car operated by an electric motor, the safety device using at least one electric battery during an electrical failure. The method is characterized in that it uses a central unit integrated into the security device to carry out:

- a frequency sweep, at the level of the electric current supply of the electric motor, to locate the precise adequate frequency generating the strongest and most stable current on the part of the electric battery, supplying the said electric motor with backup, and

- a storage of the optimal operating point of the electric motor, calculated from the data received following the scan corresponding to the strongest and most stable current. The search for the optimal operating point of the electric motor is carried out via a computer program and digital-analog and analog-digital converters. At least one brake is in the locking position of the electric motor activating the movement of the cabin during the implementation of the method, which eliminates external constraints.

The operation of the central unit during the frequency sweeping and the storage of the optimum operating point is effected when said security device is put in place, which constitutes an initialization.

The initialization of the security device consists of:

- isolate the elevator from the control panel of said elevator,

- block the electric motor activating the movement of the cabin, carry out a frequency sweep at the level of the electric motor supply,

- identify the appropriate frequency to generate the strongest and most stable current from the battery towards the motor, and

- memorize the optimal operating point in the non-volatile memory of the safety device.

In a second method of use, the operation of the central unit during the frequency sweep and the storage of the optimal operating point is carried out as soon as an electrical failure is identified which constitutes a calculation on a case by case. The case-by-case calculation of the optimal operating point consists of:

- detect an electrical failure at the elevator,

- isolate the elevator from the control panel of said elevator,

- block the electric motor activating the movement of the cabin, carry out a frequency sweep at the level of the electric motor supply,

- identify the appropriate frequency to generate the strongest and most stable current from the battery towards the motor, and

- memorize the optimal operating point in the memory of the safety device.

The safety device allowing the implementation of the process for finding the optimum operating point of the electric motor is characterized in that the central unit cooperates with:

- a power supply inverter for the engine operating elements, brakes, doors or other, and

- a memory for storing calculated values. The detection means consist of sensors for detecting the position of the car, and a fault detector, fault due to a breakdown of the elevator control panel or to a power cut, the whole being connected to The central unit. The inverter, which actuates the motor, the brake (s), the cabin doors and / or others, cooperates with a power controller of the power supplies on the winch, the brake (s), the cabin doors and / or others , the assembly being controlled by the central unit.

The power controller controls the power supplies, the values of which, for each element controlled, must lie between two threshold values previously fixed by the central unit. The attached figure is given as indicative and non-limiting examples. It represents a preferred embodiment according to the invention. It will make it easy to understand the invention.

This FIG. 1 represents a schematic view of the various elements which constitute the security device.

The principle of the present invention is to provide a safety device for an elevator which makes it possible, in the event of a breakdown of the control panel 8 of the elevator, to bring the car back to

Upstairs to free the occupants after opening the doors.

When detecting a fault, the system will isolate the lift from the main control panel using a set of relays, and will thus be able, without any risk of short circuit, to maneuver the car autonomously by 1 ' through its battery power.

The innovation consists in that the central unit 3 automatically analyzes the characteristics of the electric motor 1, generally located at the level of the winch, this analysis makes it possible to find the best speed of movement of the cabin by the safety device.

In normal operation, the electric motor 1 of the winch is supplied with a voltage of 220 or 380 volts (V) and at a frequency of 50 hertz (Hz), this in order to ensure sufficient torque allowing the cabin to be moved in the direction longed for. The safety device being powered by batteries 2, these provide a voltage of 12 V each. Of course, these values have no limiting aspect. It will therefore be necessary to work at low frequency in order to obtain sufficient torque to maneuver the cabin when the device security will be started; however, the calculation of this frequency must be very precise so that the torque is high and the speed of movement of the cabin is stable.

The central unit 3, by means of a program in machine language, performs a frequency sweep in order to locate the best frequency generating the strongest and most stable current at the level of the power supply of the winch. This research is carried out thanks to the computer program and with the aid of digital-analog and analog-digital converters. The method of using the safety device is therefore of the type which uses a central unit 3 integrated into the safety device to carry out on the one hand, a frequency sweep at the level of the electric current supply of the electric motor 1 to locate the precise adequate frequency generating the strongest and most stable current on the part of the electric battery 2 supplying the said electric motor 1 as a backup and on the other hand, a storage of the optimal operating point of the electric motor 1 calculated at from the data received following the scan corresponding to the strongest and most stable current.

In order to facilitate this method of use, the elevator is provided with at least one brake which is in the locking position of the electric motor 1 actuating the movement of the car during the implementation of the method. This arrangement eliminates external constraints, which facilitates the calculation of the optimal operating point of the electric motor 1.

Two methods can be used to implement the security device. It should be understood that the search for the operating point is not instantaneous despite the rapidity of calculation of the central unit 3. It takes about three minutes before the system has finished its search.

In a first method, the operation of the central processing unit 3, during the frequency sweeping and the storage of the optimal operating point, takes place when the safety device is installed by the installers, which constitutes a initialization.

This initialization of the safety device therefore consists in isolating the elevator from the control panel of said elevator, in blocking the electric motor 1 which actuates the movement of the cabin, to carry out a frequency sweep at the level of the power supply of the electric motor 1, to locate the appropriate frequency to generate the strongest and most stable current towards the motor 1, to memorize the optimal operating point in the memory 4 which is non-volatile of the security device and putting the security device on standby.

Conversely, the second method does not consist of a use requiring the implementation of a non-volatile memory. The operation, here, is carried out on a case-by-case basis, that is to say that the operation of the central unit 3, during the frequency scanning and the storage of the optimal operating point, is carried out as soon as an electrical failure is identified. This case-by-case calculation of the optimal operating point therefore consists in carrying out a process substantially equivalent to the initialization process. The method therefore consists of detecting an electrical failure at the elevator level on a case-by-case basis. The other steps are identical to certain steps of the initialization process. It consists first of all in isolating the elevator from the control panel 8 of said elevator, in blocking the electric motor 1 actuating the movement of the car, in carrying out a frequency sweep at the level of the supply of the electric motor and in locating the appropriate frequency to generate the strongest and most stable current from the battery 2 in the direction of the motor 1. The storage of the optimal operating point is carried out in a memory 4 which is not necessarily non-volatile, since the calculation is made on a case by case basis. However, a non-volatile memory 4 could be used if one wanted to store in memory the different optimal operating points which have been calculated during the various failures that have occurred.

Whatever the embodiment, the central unit 3 cooperates with an inverter 6 which supplies current to the operating elements such as the motor 1, the brake, the cabin doors or the like.

This inverter 6 is a converter which allows the transformation of a DC voltage into an AC voltage. The central unit 3 also cooperates with a memory 4 which makes it possible to store the calculated values. Finally, the last element to cooperate with the central unit is constituted by detection means. These detection means consist of sensors 7 for detecting the position of the car and a fault detector 5 which is due either to a failure of the control panel 8 of the elevator or to a power cut. The inverter 6 which actuates the motor 1, the brake or brakes, the cabin doors and / or others also cooperate with a power controller 9 of the power supplies on all of these elements that the inverter 6 supplies with electricity. The assembly is controlled by the central unit 3.

The power controller 9 therefore has the role of controlling the power supplies, the values of which, for each controlled element, must lie between two threshold values previously fixed and / or calculated by the central unit 3. The central unit 3 also allows to choose the most favorable direction of travel with respect to the counterweight. The choice of the most favorable direction vis-à-vis the counterweight is very important in such a system because it makes it possible to use the minimum of energy coming from the backup batteries 2. A displacement of the cabin in the unfavorable direction vis- opposite the counterweight induces a very large current consumption and therefore a large number of batteries.

In practice, whatever the embodiment of the process, the cabin can be at the level of the floor, in which case, there is no need to calculate the optimal operating point, it will suffice simply to open the doors.

If the elevator car is located between two floors, the central unit 3 will either search in its memory or calculate the optimum operating point which will allow the motor 1 of the winch to be powered and the safety device will choose the best direction of travel in order to reach the most favorable floor, which will subsequently allow the doors to open and the occupants to be released.

The electrical supply will therefore be carried out by conventional batteries of the 6 or 12 V type, for example, which supplies the inverter 6 producing a voltage at low frequency, creating sufficient torque for the operation of the elevator.

In known manner, alert means can be used which can be constituted, on the one hand, by a voice synthesizer 11 located in the elevator cabin which can warn the occupants thereof, via a loudspeaker 12, that the safety device is activated and that they will soon be able to exit, and on the other hand , a remote alarm using a high frequency transmitter 13 and a receiver of the same type 14 which communicate via antennas 15 and 16.

The batteries 2 are kept charged by means of a charger 10 supplied by the network.

There is also, at the charger 10, a battery charge level controller 2, which makes it possible to control the charge value of said batteries 2.

When this value is below a predetermined threshold, the level controller triggers an alarm via the transmitter 13, the receiver 14 of which may, for example, be located in the premises of the guards.

REFERENCES

1. Electric motor

2. Electric heater

3. Central processing unit 4. Memory

5. Fault detector

6. Inverter

7. Sensors for detecting the position of the elevator car

8. Elevator control panel 9. Power controller

10. Charger

11. Elevator voice synthesizer

12. Speaker

13. Alarm transmitter 14. Alarm receiver

15. Transmitter antenna 13

16. Receiver antenna 14

Claims

1. Method of using a safety device for an elevator of the type using a cabin actuated by an electric motor (1), the safety device using at least one electric battery (2) during an electrical failure, characterized by the fact that the method uses a central unit (3) integrated into the security device to carry out: - a frequency sweep, at the level of the electric current supply of the electric motor (1), to locate the precise adequate frequency generating the strongest and most stable current on the part of the electric battery (2) supplying rescue said electric motor (1), and - a storage of the optimum operating point of the electric motor (1), calculated from the data received following the scan corresponding to the strongest and most stable current. 2. Method according to claim 1, characterized in that the search for the optimum operating point of the electric motor (1) is carried out by means of a computer program and digital-analog and analog-digital converters. 3. Method according to claim 1, characterized in that at least one brake is in the locking position of the electric motor (1) actuating the movement of the cabin during the implementation of the method, which eliminates external constraints . 4. Method according to any one of claims 1, 2 or 3, characterized in that the operation of the central unit (3) during the frequency scanning and the storage of the optimum operating point takes place to the installation of said security device, which constitutes an initialization. 5. Method "according to claim 4, characterized in that the initialization of the security device consists in: - isolate the elevator from the control panel of said elevator, - block the electric motor (1) activating the movement of the cabin, carry out a frequency sweep at The electric motor supply (1), - identify the appropriate frequency to generate the strongest and most stable current from the battery (2) towards the motor (1), and - store the optimal operating point in the non-volatile memory (4) of the security. 6. Method according to any one of claims 1, 2 or 3, characterized in that the operation of the central unit (3) during the frequency scanning and the storage of the optimum operating point is carried out as soon as an electrical failure is identified, which constitutes a case-by-case calculation. 7. Method according to claim 6, characterized in that the calculation on a case-by-case basis of the optimal operating point consists in: - detect an electrical failure at the elevator, - isolate the elevator from the control panel of said elevator, - block the electric motor (1) activating the movement of the cabin, - carry out a frequency sweep at the power supply to the electric motor (1), - locate the "appropriate frequency ^~ to generate the strongest and most stable current from the battery (2) towards the motor (1), and - store the optimal operating point in the memory (4) of the security. 8. Safety device allowing the implementation of the method according to any one of claims 1, 2, 3, 4 or 6, characterized in that the central unit (3) cooperates with: an inverter (6) for supplying current to the operating elements of the motor (1), brakes, doors or the like, and - a memory (4) for storing calculated values. 9. Device according to claim 8, characterized in that the detection means consist of: - cabin position detection sensors (7), and - a fault detector (5), fault due to a fault in the switchboard (8) of the elevator or a power cut, all connected to the central unit (3). 10. Device according to claim 8, characterized in that the inverter (6), which actuates the motor (1), the brake or brakes, the cabin doors and / or others, cooperates with a power controller ( 9) power supplies on the winch, the brake or brakes, the cabin doors and / or others, the assembly being controlled by the central unit (3). 11. Device according to claim 10, characterized in that the power controller (9) controls the power supplies whose values must, for each element checked, be between two threshold values previously set by the central unit (3) .