EP0287868B1 - Method and device for monitoring the alighting area of a ski lift - Google Patents

Abstract

In order to monitor alighting areas (1) of ski lifts, this area is divided into three successive monitoring zones (2, 3, 4). The movements of occupied ski lift arms (11) are monitored by means of magnetic field sensors (10). In addition, the presence of the conveyed persons in the monitoring zones (2, 3, 4) is preferably detected by means of capacative proximity sensors (20). A central analysing electronic unit switches the ski lift drive on in the event of any deviation of the signal sequence relayed by the sensors from a predetermined signal sequence. <IMAGE>

Description

The invention relates to a method for monitoring a disembarking place for drag lifts, which is divided into three successive monitoring zones, the first of which forms an entry zone, the second an exit zone and the third a delimitation zone, monitoring signals being transmitted from sensors to a central evaluation electronics, and if the transmitted signal sequence deviates from a signal sequence predetermined for the evaluation electronics, the drag lift drive is switched off, and a monitoring device for carrying it out.

Up to now, it has been customary to monitor the disembarking places of drag lifts by an operator who is positioned near the disembarking place during the operating period. Continuous surveillance requires a high level of concentration so that inattentiveness cannot be avoided even through monotony. Even if it is rare, this leads to serious accidents, since the lift bars do not retract properly, skiers block the disembarking place, etc.

Such a device has become known from DE-A-2516777, in which scanning beams, in particular modulated light beams, and interruptions of the beams by sensors detecting obstacles are used to monitor the alighting area. Furthermore, it is known from DE-A-2558695 to use a television camera to monitor the alighting area, which scans a patterned or striped control surface, changes in the pattern of the control image being recognized by obstacles.

The disadvantage of such monitoring devices is in the multitude of possible disturbances, for example due to heavy snowfall, which can appear as a physical obstacle for scanning light rays, or, for example, when snow is blown by wind, which changes a patterned or striped control area into a closed white area in the shortest possible time. Furthermore, mechanical adjustments and effects from deliberate contact by skiers etc. cannot be prevented, which of course also cause interference signals. The activity of the operator shifts here from the observation of the disembarking place to the observation of the monitoring elements, but there is no relief for the operator.

The object of the invention is to provide a method and a monitoring device for the disembarking place of drag lifts that is as non-disruptive as possible so that an operator can be effectively relieved.

According to the invention, this is achieved in that a magnetic field is assigned to each drag lift bar and the movement path of each occupied drag lift bar is monitored by means of magnetic field sensors from the entry into the entry zone at least until the exit from the boundary zone.

The method according to the invention is thus primarily able to monitor the timely release of the occupied stirrups as an essential prerequisite for the clearing of the disembarking place by the transported skiers, so that the operator is effectively relieved.

The magnetic field sensors are used to monitor the correct movement sequence of the occupied tow lift bracket Ordered along its path of movement, ie in the entry zone in the ground or possibly also in a ground clearance corresponding to its towing position to the side next to the lane, and in the boundary zone behind a bar grate usually provided there.

Since, in a preferred embodiment, the trajectory of the drag lift bracket is monitored until it is completely drawn into the hanger, a magnetic field sensor can also be provided for this purpose near the deflection plate at a point where the bracket must be retracted. Depending on the size of the alighting area, further magnetic field sensors can be provided in the floor in the alighting zone and at any other positions of the monitoring area. Each drag lift bracket is preferably equipped with a permanent magnet to form the magnetic fields.

A supplementary embodiment of the method can provide that additional monitoring of the entry zone and the exit zone is carried out by means of capacitive presence sensors which, when a drag lift bracket enters the entry zone and a person is present in the exit zone, produce an interference signal which causes the signal sequence to deviate.

This means that the complete clearing of the disembarkation area, including its crossing by other skiers, is monitored when an occupied drag lift bracket follows.

If additional monitoring is carried out in the boundary zone by means of a capacitive presence sensor which, in the event of a missing signal from the magnetic field sensor at the exit of the boundary zone, generates an interference signal which causes the signal sequence to deviate, so all conceivable possibilities are covered. In this embodiment, the predefined signal sequence is advantageously composed of two rows nested one inside the other, one of which is assigned to the lift lifts released and the other to the people present.

The specified signal sequence, which corresponds to the undisturbed operation of the tow lift, is adapted to the circumstances and the safety regulations. In principle, a large number of sensors could be used to define signal sequences that detect even the smallest deviations from the ideal state and thereby switch off the tow lift too frequently. For a reasonable compromise for personal surveillance, which ensures undisturbed operation over an average period of time, it is sufficient if the signal sequence specified for the evaluation electronics for monitoring the movement path of the people carried per occupied drag lift bracket includes an entry signal from the magnetic field sensor from the entry zone, no interference signal from the capacitive presence sensor from the exit zone, an exit signal of the magnetic field sensor at the end of the boundary zone and no interference signal of the capacitive sensor from the boundary zone.

With such a signal sequence, it can normally be assumed that the skiers have freed themselves from the drag lift bracket in good time, cleared the disembarking place in order not to hinder the subsequent skiers from getting off, and that the bracket that is released is completely drawn into the hanger within a certain time.

Since a presence signal from the alighting zone only represents an interference signal when there is an entry signal from the entry zone, skiers can easily enter the disembarkation zone remain as long as subsequent drag lift bars are unoccupied. The disembarking zone must be cleared only when a manned tow lift bracket enters the entry zone.

It is also possible to take care of several mountain lifts close to each other, as is often the case in larger ski areas, by a single operator, who no longer checks the normal status regarding the care of the disembarking places, but only the elimination of accidents Has.

A preferred monitoring device for monitoring the disembarking place of drag lifts, which is divided into three successive monitoring zones, the first of which forms an entry zone, the second an exit zone and the third a limiting zone, with at least one sensor for each monitoring zone, with a sensor for determining the Driving speed and with central evaluation electronics is characterized in that the monitoring device has a plurality of magnetic field sensors to be arranged along the movement path of the occupied drag lift bracket equipped with a permanent magnet, an inductive proximity switch to be arranged as a driving speed sensor on the last lift support in front of the disembarking place and one to be arranged eccentrically on the rope pulley. has at least one pulse per revolution in the proximity switch triggering pin.

The driving speed sensor serves to specify the time intervals of the monitoring signals to be expected as a function of the driving speed.

Furthermore, it is preferably provided that in the entry zone, in the alighting zone and in the delimitation zone at least one further sensor is formed by a capacitive presence sensor which is arranged inside the snow cover, in particular in the ground.

The invention will now be described in more detail below with reference to the figures in the accompanying drawings, without being limited thereto.

Fig. 1 shows a schematic plan view of the top station of a drag lift with one-sided exit, Fig. 2 shows the disembarking place in a schematic side view, Fig. 3 shows an example of the monitoring zone division with double-sided exit, Fig. 4 and 5 arrangements of a magnetic field sensor and a speed sensor.

The top station of a drag lift (FIG. 1) has a rope deflection disk 18 for the tow rope 19, on which the hangers 9 of the drag lift bracket 11 are clamped at intervals. The end of the drag lift route is formed, for example, by a slatted frame 22, behind which a conventional safety line can be stretched for switching off. A conventional button 24 for switching off the lift system is provided at a suitable point. The alighting area 1 is divided into monitoring zones and comprises at least one entry zone 2, one alighting zone 3 and one delimitation zone 4. FIG. 3 shows an advantageous zone division for an alighting area with an exit on both sides.

In the entry zone 2, a first magnetic field sensor 10 is arranged in the snow or in the ground 7 under the lane, if appropriate also laterally at the level of the occupied t-bar 11 (FIG. 2). The magnetic field sensor 10 responds to a permanent magnet 12 (FIG. 4) that each drag lift bracket 11 is provided. The first magnetic field sensor 10 is used to monitor whether the drag lift bracket 11 is occupied by skiers, since only then does the permanent magnet 12 pass the detection range of the first sensor 10, and thus to activate the monitoring device. Furthermore, a speed sensor 13 (FIG. 5) is provided in the entry zone 2 in the area of a rope pulley 15 of the last lift support 16. This detects the speed of the pulley 15 and thus the speed of the drag lift. The speed sensor 13 consists of a proximity switch 14 in which a signal is triggered by at least one pin 17 protruding eccentrically with each revolution of the pulley 15. The signals are proportional to the driving speed and define the time intervals to all further monitoring signals, which have to be emitted by further sensors before leaving the alighting area 1 if a occupied lifting bracket 11 is detected by the first magnetic field sensor 10. Additional magnetic field sensors can be provided in the floor up to the exit area. A necessary magnetic field sensor 10 is arranged behind or under the inclined grate 22 or at the end of the alighting area 1, with the aid of which it is monitored whether the bracket is released in time in the alighting zone 3 within the intended travel route. If a skier is caught on the bracket 11, the latter retracts late and passes the bar grating 22 with a delay.

A last sensor 10, which can also be a magnetic field sensor, can also be provided at a point near the deflection plate 18, at which the bracket 11 must be completely drawn into the hanger. If a magnetic field sensor is used, its arrangement can be based on a mast 23 according to FIG. 4. If the bracket 11 passes too low, the last sensor 10 does not respond, and the drag lift drive is switched off. At this point, another device can also be used as the sensor, for example a touch switch, which responds to a tow lift bracket 11 that has not yet calmed down.

A central evaluation electronics processes all signals coming from the individual sensors and compares them with the given signal sequence, switching off the lift drive in the event of deviations. The assigned process computer is freely programmable.

In the case of trouble-free operation, the monitoring proceeds as follows:
If a drag lift bracket 11 is occupied, the built-in permanent magnet 12 passes the detection area of the first magnetic field sensor 10 in the entry zone 2. An entry signal is generated which activates the speed sensor 13. From this point in time, the travel distance determined by the speed sensor 13 and the chronological sequence of the monitoring signals to be expected from the further sensors are monitored. The skiers let go of the bracket 11 in the disembarking zone, the retraction of which along the movement path is detected by the further magnetic field sensors 10. Since these correspond to the given sequence, the drag lift continues to run.

In order to be able to monitor the exit of the exit zone 3 by the skiers, further sensors in the form of capacitive presence sensors 20 are provided in each of the three zones 2, 3, 4, which generate corresponding signals.

As soon as the magnetic field sensor 10 assigned to the bar grate 22 has indicated the correct release of the bracket 11, the control of the movement path between entry and exit is switched to inactive, presence signals from the presence sensor 20 in the exit zone 3 being ignored. However, the presence signal from the exit zone 3 is taken into account if it is still present at the next entry signal. An intercom system can be provided so that announcements and instructions can be given to the disembarkation point 1 from the embarkation point. If there is a presence signal from the limiting zone 4, the drive is switched off if either the magnetic field sensor 10 below the grating 22 has not emitted an exit signal, or if there is a new entry signal from the entry zone 2.

Likewise, a presence signal from the entry zone 2 leads to a switch-off, even if an entry signal from the entry zone indicates the next tow lift bracket 11 that is occupied. Any other deviation from the specified signal sequence, for example due to a too long period of time between signals from the magnetic field sensors, or due to a presence indicator from one of the zones 2, 3, 4 due to skiers crossing and a simultaneous entry signal from the entry zone 2, leads to the switch-off of the Drag lift drive. A defect in a monitoring system can also be detected, since at least the entry signal into the entry zone 2 can be assigned to both systems and the defect no longer generates any further predetermined signals.

Claims (7)

1. A method of monitoring an alighting area (1) of ski drag lifts, which is divided into three successive monitoring zones of which the first zone forms an entry zone (2), the second forms an alighting zone (3) and the third forms a limit zone (4), wherein monitoring signals are transmitted from sensors (10, 20) to a central electronic evaluation means and if the transmitted signal sequence departs from a signal sequence which is predetermined by the electronic evaluation means the drag lift drive is switched off, characterised in that a magnetic field is associated with each drag lift bar member (11) and the path of movement of each occupied drag lift bar member (11) is monitored by means of magnetic field sensors (10) from its entry into the entry zone (2) at least as far as its exit from the limit zone (4).
2. A method according to claim 1 characterised in that the path movement of the drag lift bar members (11) is monitored until they are drawn completely into the respective suspension member (9).
3. A method according to claim 1 or 2 characterised in that additional monitoring of the entry zone (2) and the alighting zone (3) is effected by means of capacitive presence sensors (20) which produces a fault signal causing a deviation of the signal sequence when an occupied drag lift bar member (11) passes into the entry zone (2) and a person is present in the alighting zone (3).
4. A method according to one of claims 1 to 3 characterised in that additional monitoring of the limit zone (4) is affected by means of a capacitive presence sensor (20) which produces a fault signal causing a deviation of the signal sequence in the absence of a signal from the magnetic field sensor (10) at the exit of the limit zone (4) and when a person is present in the limit zone.
5. A drag lift bar member for carrying out the method according to claim 1 or claim 2 characterised in that the drag lift bar member (11) is fitted with a permanent magnet (12).
6. A monitoring arrangement for monitoring the alighting area (1) of ski drag lifts, which is divided into three successive monitoring zones of which the first forms an entry zone (2), the second forms an alighting zone (3) and the third forms a limit zone (4), having at least one sensor (10) for each monitoring zone (2, 3, 4), a sensor (13) for detecting the speed of travel and a central electronic evaluation means, characterised in that the monitoring arrangement has a plurality of magnetic field sensors (10) to be arranged along the path of movement of the occupied drag lift bar members (11) fitted with a permanent magnet, an inductive proximity switch which is to be arranged as a travel speed sensor (13) at the last lift support (16) before the alighting area (1), and a pin (17) which is to be arranged eccentrically on the cable roller (15) and which triggers at least one pulse in the proximity switch (14) per revolution.
7. A monitoring arrangement according to claim 6 characterised in that at least one further respective sensor is formed in each of the entry zone (2), the alighting zone (3) and the limit zone (4) by a capacitive presence sensor (20) which is arranged within the covering of snow, in particular in the ground (7).

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