EP0143681B1 - Method and device for controlling the correct functioning of a cable car transport installation - Google Patents

Abstract

1. A method for controlling the correct functioning of an aerial cable transport installation (12, 40) driven by an electric motor (10, 46) and which may transport cars (14, 38) with variable loads (P) along the transport line extending between two stations, in which installation the instantaneous cable driving power (W) is measured and represented by a signal, characterized in that the data of the line are registered in a memory unit (26, 58) for the calculation of the normal cable driving power in accordance with the transported load, the car positions (14, 38) along the line and the cable speed (V), in that at each moment the data relating to the cable speed, the load value of the cars on the line and the car positions on the line are provided to a central processing unit (18, 50) which reads in the memory unit (26, 58) the data for elaborating therefrom a signal representing said normal power and that said normal power signal and instantaneous power signal are permanently compared in a comparator unit (34, 62) to elaborate an output signal which represents the difference between said powers, said output signal providing an alarm and/or an installation stopping when it passes a predetermined threshold.

Description

The invention relates to a method and a device for controlling the operating state of an overhead cable transport installation driven by an electric motor and capable of transporting vehicles of variable load along a line of displacement extending between two stations, in which installation the instantaneous cable drive power is measured and translated by a signal.

In installations of the type indicated, in particular cable cars, chairlifts and cable cars, the tractor or carrier-tractor cable is driven by a power station and the movement is transmitted by the cable over a path of several hundred meters or even over kilometers, including surveillance over the entire route is practically impossible. User safety nevertheless requires instant detection of any incident at any point in the installation, and detectors are known for cable derailment or untimely movement of the cable tension counterweight. The derailment detectors must be placed in line with each cable guide pulley and be connected by an electrical safety line extending along the installation, while the operation of the detector associated with the counterweight is unreliable.

It has already been proposed (see for example the method described in FR-A-2 122 809 and corresponding to the preamble of claim 1) to detect untimely variations, in particular of the power consumed by the drive motor, but the Sensitivity of these devices is necessarily limited if we want to avoid tripping in normal operation and they are unable to detect a slow variation due for example to wear or seizure.

The object of the present invention is to remedy these drawbacks by carrying out permanent monitoring of the operation of the installation. It starts from the observation that the driving power of the cable at a given time is a function of the speed of the cable, the slope of the cable at the location of the vehicle (s) along the line, the load carried by the or vehicles and the condition of the facility. By determining the first three parameters, it is therefore possible to check the operating status of the installation.

The method according to the invention is characterized in that the line data is recorded in a memory unit for the evaluation of the normal driving power of the cable as a function of the value of the load transported, of the position of the vehicles in line and the speed of the cable, which is supplied to a central processing unit with data to know the speed of cable drive, the value of the load of the vehicles in line and the position of the vehicles in line each instant, said central unit interrogating the memory unit to generate from said data a signal representative of said normal power and that said normal power and instantaneous power signals are continuously compared in a comparison block to develop a representative output signal the difference between said powers, said output signal triggering an alarm and / or a device for stopping the installation when a predetermined threshold is crossed completed. It is even possible not to integrate the payload of the inserted vehicles, by using as a reference base, the powers consumed in a relatively short period after the speeding up of the vehicles (fixed or disengageable).

We know that the force necessary to move a load P on a slope of an angle α is given by the formula P sin α, the power being V - P - sin a, if V is the speed of displacement. It is of course appropriate to add the friction forces and the inertial forces in the event of a speed variation, but these forces can be evaluated or measured at the origin and it is possible to take them into account. In the case of an installation with fixed attachments, in particular of a cable car with a single skip, the position of the vehicle is given by the movement of the winch of the towing cable and it suffices to record the profile of the line and read this recording during the movement of the vehicle to have the data for calculating the normal power, if care is taken to count or weigh the passengers on board. The memory unit and the central processing unit can be very simple and produced by any suitable means. If the cable car has two skips, calculate the normal power for each skip and deduct the resulting total normal power.

For more complex installations with detachable vehicles, in particular gondolas, the control device receives the starting information at each clutch of a cabin in one or the other of the stations, at the same time as the information of the load. transported. The control device is advantageously in this case a computer, which tracks each cabin during its online movement and knowing at all times the different positions of the cabins, their loads, the speed of the gondola and the profile of the line, can calculate or determine the normal drive power of the cable. A simple comparator, for example a differential amplifier and a threshold circuit, allows signaling of a notable difference between instantaneous and normal powers. Abnormal advancement resistance can thus be detected before the incident or accident and allows preventive intervention.

• la figure 1 est une vue schématique d'un téléphérique à une seule benne, équipé d'un dispositif de contrôle selon l'invention ;
• la figure 2 représente la courbe de variation de la puissance d'entraînement en fonction de la position de la benne du téléphérique selon la fig. 1 ;
• la figure 3 est une vue analogue à celle de la fig. 1, montrant une télécabine.

Other advantages and characteristics will emerge more clearly from the description which follows of two embodiments of the invention, given by way of nonlimiting examples and represented in the appended drawings, in which :

• Figure 1 is a schematic view of a cable car with a single bucket, equipped with a control device according to the invention;
• FIG. 2 represents the variation curve of the driving power as a function of the position of the cable car grab according to FIG. 1;
• Figure 3 is a view similar to that of FIG. 1, showing a gondola.

In FIG. 1, a cable car comprises a motor 10 for driving the winch of the towing cable 12 of a bucket 14 circulating between the two stations A and B. For reasons of simplicity of the description it is assumed that the cable car comprises a single bucket. A scale 16 weighs the passengers embarking in the bucket 14 and provides a signal P of the total weight of the bucket 14 to a central processing unit 18 of a control device designated by the general reference 20. A tachometer generator 22 coupled to the motor 10 provides this central unit 18 with a signal V of speed of the cable 12. The motor 10 drives by a transmission 24 a magnetic tape recorder 26 with read heads 28, 30. The strip 26 moves in synchronism with the bucket 14 and the read heads 28, 30 read the recorded information corresponding to the location of the bucket online. One of the recording tracks of tape 26 can represent the profile of the line, in this case the abscissas and ordinates of the ends of the staff, while the other track can represent correction factors, in particular at the start. and braking the bucket, as well as an increase in friction when passing a pylon. The central unit 18 permanently has the stored information read by the heads 28, 30 and the speed and load information and this data is transmitted to a calculation unit 32 which determines the normal drive power of the cable 12. The signal of calculated normal power is supplied to a comparator 34 which receives an instantaneous power signal emitted by a measuring device 36 of the electric power W supplied to the motor 10. The comparator 34 indicates the difference between these two powers and triggers an alarm or stops the installation if this difference exceeds a predetermined threshold. The control device can be simplified if the load transported is substantially constant and if the installation operates at one or two predetermined speeds. It is then possible to store directly on the tape 26 the normal drive power for each of the speeds and to read the information corresponding to the selected speed, the control device being limited to the comparator 34. It is clear that the speed signal can be calculated by the central unit, which may include a clock, on the basis of a signal for movement of the strip 26 and that the cabin load can be determined in a different manner.

FIG. 2 shows an example of variation of the power as a function of the location of the bucket 14 on the line. The power difference can be permanent or at a given location which makes it possible to locate the anomaly.

On the descent path of the bucket 14, a scale (not shown) at station B supplies the load signal P and the control device 20 receives slope change information.

Referring to Figure 3, we can see a station of a detachable single cable gondola. The cabins 38 are disengaged from the carrier-tractor cable 40 in the stations and run on transfer rails 42. At the outlet, the cabins 38 are engaged on the cable 40, which is permanently driven by a driving pulley 44 coupled to a motor. electric 46. The clutch of a cabin 38 is signaled by a through contact 48, which sends a start signal to a central unit 50 of a control computer 52. A scale 54 weighs the people embarking in the cabin and the corresponding signal P is transmitted to the central unit 50. This unit 50 also receives a displacement signal emitted by a pulse wheel 56 coupled to the driving pulley 44. The computer 52 includes a memory 58 in which are recorded the characteristics of the line, in particular the online profile and a calculation unit 60, the time base being provided by a clock. The computer 52 emits a normal power signal transmitted to a comparator 62, which compares this signal with an instantaneous power signal W supplied by a Wattmeter 64 for measuring the electric power W supplying the motor 46.

• Lors de l'installation de la télécabine on introduit dans la mémoire 58 les données relatives à la ligne, en particulier le profil de la ligne. Lors de l'embrayage de la première cabine 38, signalé par le contact 48, l'ordinateur 52 enregistre la charge P transportée, mesurée par la balance 54 et il suit la cabine dans sa progression le long de la ligne à partir des impulsions de déplacement fournies par la roue 56. Il opère de même pour les cabines suivantes partant de l'une et de l'autre des stations. A chaque instant l'ordinateur connaît la position de chaque cabine et sa charge. En interrogeant la mémoire 58 il connaît la pente de la ligne à l'emplacement de la cabine et il peut calculer à partir du signal de déplacement la vitesse. Il dispose ainsi de tous les éléments pour calculer la puissance normale d'entraînement de chaque cabine et d'élaborer le signal de puissance normale d'entraînement du câble 40, lequel signal est comparé dans le comparateur 62 au signal de puissance réelle.

The device according to FIG. 3 operates as follows:

• During the installation of the gondola, the data relating to the line, in particular the profile of the line, is entered into memory 58. When the first cabin 38 is engaged, signaled by the contact 48, the computer 52 records the load P transported, measured by the balance 54 and it follows the cabin in its progression along the line from the pulses of displacement provided by the wheel 56. It operates in the same way for the following cabins departing from one and the other of the stations. At all times the computer knows the position of each cabin and its load. By interrogating memory 58, it knows the slope of the line at the location of the cabin and it can calculate the speed from the displacement signal. It thus has all the elements for calculating the normal drive power of each cabin and of developing the normal drive power signal of the cable 40, which signal is compared in the comparator 62 with the real power signal.

The invention is of course applicable to any type of air carrier, the computer being able at the same time to perform other functions, for example counting and optimizing the speed or number of cabins in line. The direct weighing system can be replaced by a measurement of the powers consumed for a short period after the gearbox has been put into gear or the clutch and a calculation by the corresponding load computer, which simplifies installation and application to existing installations.

Claims (9)

1. A method for controlling the correct functioning of an aerial cable transport installation (12, 40) driven by an electric motor (10, 46) and which may transport cars (14, 38) with variable loads (P) along the transport line extending between two stations, in which installation the instantaneous cable driving power (W) is measured and represented by a signal, characterized in that the data of the line are registered in a memory unit (26, 58) for the calculation of the normal cable driving power in accordance with the transported load, the car positions (14, 38) along the line and the cable speed (V), in that at each moment the data relating to the cable speed, the load value of the cars on the line and the car positions on the line are provided to a central processing unit (18, 50) which reads in the memory unit (26, 58) the data for elaborating therefrom a signal representing said normal power and that said normal power signal and instantaneous power signal are permanently compared in a comparator unit (34, 62) to elaborate an output signal which represents the difference between said powers, said output signal providing an alarm and/or an installation stopping when it passes a predetermined threshold.

2. Method according to claim 1, characterized in that the data relating to the line profil, particularly the distance and the height of tower heads are entered in said memory unit (26, 58) and that the central unit (18, 50) calculates the driving power in accordance with the car position, its load (P), the driving speed (V) and the slope at this position.

3. Method according to claim 1 or 2, characterized in that one enters in said memory unit (40) at the start of a car from a station, the starting time and the value of the load transported by the car (38) and that the central unit (50) calculates at each moment the car position on the line and the normal car driving power.

4. Method according to claim 1, 2 or 3, for an installation having a plurality of cars on the line, characterized in that the central unit (50) calculates for each car (38) on the line the normal driving power and by adding these normal powers for all the vehicles calculates the normal driving power of the installation.

5. Method according to claim 3 or 4, characterized in that the information about the transported load value is deducted and/or calculated by the central unit (18, 50) from the instantaneous power measurement just after the acceleration or coupling of the car on the cable (12, 40).

6. Device for the realization of the method according to anyone of the preceding claims, characterized in that it comprises a measuring device (36, 64) of the instantaneous cable (12, 40) driving power (W), a weighting device (16, 54) of the loads in said cars (14, 38), a cable speed (V) measuring device (22, 56), a memory unit (26, 58) for registering the data which characterize the installation for the calculation of the normal driving power in function of the speed (V), the loads (P) and the car position on the line, a central unit (18, 50) for the determination of said normal power and a comparator unit (34, 62) for the determination of the difference between this normal power and the instantaneous power, said comparator unit providing an alarm signal and/or a stopping when said difference passes over a predetermined threshold.

7. Control device according to claim 6, characterized in that said weighting device (16. 54) adds the weight of the passengers in the car (14, 38) and the weight of the car.

8. Device according to claim 6 or 7, characterized in that said central unit (18, 50) comprises a calculating unit (32. 60) to multiply the load signal (P) and the speed signal (V) and to multiply this product by the slope signal sin a, given by the memory unit (26, 58), a being the slope angle of the line at the car position.

9. Device according to claim 6, 7 or 8, characterized in that it comprises a start detector (48) giving to the control unit (50) the car, start signal (38), a measuring device (56) of the cable (40) movement so that the central unit (50) knows the car position on the line and may determine for each car the required power part of the normal driving power.

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