SAFETY DEVICE OF A LIFT SYSTEM

Abstract

A safety device of a lift system may include a car comprising an evaluation device and a measuring device. Conditions where departure from a door zone with an open car door or where impermissible accelerations/speeds are reached within the door zone are identifiable by way of the evaluation device and output signals from the measuring device. In such conditions, a control signal may be generated for braking the car. A safety circuit may be connected to the evaluation device and ensure a first safe zone in a shaft head of a lift shaft during an inspection run. The safety circuit may have a safety switch, and the car may include a tripping means for tripping the safety switch. The safety switch and the tripping means have a first relative position upon which the first safe zone is based, and entry of the car into the first safe zone during the inspection run is preventable by tripping the safety switch, which leads to generation of the control signal and braking of the car.

Claims

1.-13. (canceled)

14. A safety device of a lift system having a lift car, the safety device comprising: an evaluation device; a measuring device, wherein by way of the evaluation device and output signals from the measuring device, conditions where the lift car departs from at least one door zone with an open door, where the lift car reaches an impermissible acceleration within the at least one door zone, or where the lift car reaches an impermissible speed within the at least one door zone are detectable and a control signal for braking the lift car is generated; and a safety circuit that is connected to the evaluation device to ensure a first safe zone in a shaft head of a lift shaft during an inspection run, wherein the safety circuit includes a safety switch and the lift car includes tripping means for tripping the safety switch, wherein the safety switch and the tripping means have a first position relative to each other based on which the first safe zone is defined, so that the lift car can be prevented from moving into the first safe zone during the inspection run by tripping the safety switch, which causes the evaluation device to generate the control signal for braking the lift car.

15. The safety device of claim 14 further comprising a drive motor, wherein deactivation of the drive motor is effected by the control signal.

16. The safety device of claim 14 further comprising an operating brake, wherein engagement of the operating brake is effected by the control signal.

17. The safety device of claim 14 wherein the safety circuit is inactive during a normal run.

18. The safety device of claim 14 wherein a position of at least one of the safety switch or the tripping means is variable, wherein the safety switch and the tripping means have a second position relative to each other based on which a second safe zone in the lift shaft is defined, so that the lift car can be prevented from moving into the second safe zone during a normal run by tripping the safety switch, which causes the evaluation device to generate the control signal for braking the lift car.

19. The safety device of claim 18 wherein the tripping means is displaceable in a vertical direction with respect to the lift car between the first position and the second position such that a vertical extent of the first safe zone is greater than a vertical extent of the second safe zone.

20. The safety device of claim 14 wherein the safety circuit comprises a switch for monitoring a position of the tripping means.

21. A lift system comprising: a lift car that is movable in a lift shaft; and a safety device that includes an evaluation device, a measuring device, wherein by way of the evaluation device and output signals from the measuring device, conditions where the lift car departs from at least one door zone with an open door, where the lift car reaches an impermissible acceleration within the at least one door zone, or where the lift car reaches an impermissible speed within the at least one door zone are detectable and a control signal for braking the lift car is generated, and a safety circuit that is connected to the evaluation device to ensure a first safe zone in a shaft head of a lift shaft during an inspection run, wherein the safety circuit includes a safety switch and the lift car includes tripping means for tripping the safety switch, wherein the safety switch and the tripping means have a first position relative to each other based on which the first safe zone is defined, so that the lift car can be prevented from moving into the first safe zone during the inspection run by tripping the safety switch, which causes the evaluation device to generate the control signal for braking the lift car.

22. The lift system of claim 21 further comprising a drive motor, wherein deactivation of the drive motor is effected by the control signal.

23. The lift system of claim 21 further comprising an operating brake, wherein engagement of the operating brake is effected by the control signal.

24. The lift system of claim 21 wherein the safety circuit is inactive during a normal run.

25. The lift system of claim 21 wherein a position of at least one of the safety switch or the tripping means is variable, wherein the safety switch and the tripping means have a second position relative to each other based on which a second safe zone in the lift shaft is defined, so that the lift car can be prevented from moving into the second safe zone during a normal run by tripping the safety switch, which causes the evaluation device to generate the control signal for braking the lift car.

26. The lift system of claim 25 wherein the tripping means is displaceable in a vertical direction with respect to the lift car between the first position and the second position such that a vertical extent of the first safe zone is greater than a vertical extent of the second safe zone.

27. The lift system of claim 25 wherein the lift car includes a railing that is disposed on a lift car roof and is displaceable in the vertical direction between a first position and a second position.

28. The lift system of claim 27 wherein the safety circuit comprises a switch that monitors a position of the railing.

29. The lift system of claim 27 wherein the railing is coupled to the tripping means such that the railing and the tripping means are displaceable only jointly between the first position and the second position.

30. A method for operating a lift system having a lift car and a safety device that comprises an evaluation device; a measuring device; and a safety circuit that is connected to the evaluation device to ensure a first safe zone in a shaft head of a lift shaft in an inspection mode, wherein the safety circuit includes a safety switch and the lift car includes tripping means for tripping the safety switch, wherein the safety switch and the tripping means have a first position relative to each other based on which the first safe zone is defined, the method comprising: in a normal mode detecting based on output signals from the measuring device conditions where the lift car departs from at least one door zone with an open car door, where the lift car reaches an impermissible acceleration within the at least one door zone, or where the lift car reaches an impermissible speed within the at least one door zone, and generating a control signal for braking the lift car when any of the conditions is detected; and in the inspection mode generating the control signal for braking the lift car based on tripping of the safety switch, which prevents the lift car from moving into the first safe zone.

31. The method of claim 30 further comprising deactivating a drive motor upon generation of the control signal.

32. The method of claim 30 further comprising engaging an operating brake upon generation of the control signal.

Description

[0027] The invention will be explained in more detail by using the figures, in which:

[0028] FIG. 1 shows a schematic illustration of a lift system,

[0029] FIG. 2 shows a detailed illustration of the lift head during an inspection run,

[0030] FIG. 3 shows a detailed illustration of the lift head during a normal run,

[0031] FIG. 4 shows a detailed illustration of the lift head during a normal run in an alternative design variant.

[0032] FIG. 1 shows, schematically, a lift system 1 comprising a lift car 3, which can be moved upward and downward in the vertical direction in a lift shaft 7 by means of a drive device 5, wherein it can stop at various stopping points, of which only three stopping points 9, 11, 13 are illustrated in FIG. 1, in order to be loaded and unloaded.

[0033] The drive device 5 comprises a drive motor 15 which is controlled by a controller 17, wherein a supply voltage is provided to the drive motor 15 via the controller 17. In addition, the drive device 5 comprises a drive pulley 19, which is set rotating by the drive motor 15. A cable 21 is led around the drive pulley 19 and connects the lift car 3 to a counterweight 23. The drive pulley 19 is assigned an operating brake 25 which, just like the controller 17, is connected to a lift control system 27.

[0034] At each stopping point 9, 11 and 13, zone flags 29 which can be detected by a door sensor 31 are arranged in the lift shaft 7. The door sensor 31 is fixed to the lift car 3 and connected to the lift control system 27. The zone flag 29 predefines a door zone. As long as the door sensor 31 detects the zone flags 29, the lift car 3 is located within the door zone.

[0035] As already mentioned, the lift car 3 can be moved in the lift shaft 7 by means of the drive device 5. For the purpose of loading and unloading, the lift car 3 can assume a position flush with a stopping point 9, 11, 13. The weight of the lift car 3 changes as a result of the loading and unloading. This can lead to the lift car 3 changing its position slightly relative to the stopping point 9, 11, 13. It is then possible for the position of the lift car 3 relative to the respective stopping point 9, 11, 13 to be readjusted by the drive device 5 being activated. The adjustment movement is carried out here at very slow speed and very low acceleration within the door zone which is predefined by the zone flag 29.

[0036] As the lift car 3 approaches a stopping point 9, 11, 13, the lift car door 33 can already be opened even before the lift car 3 has reached its flush position. The lift car door 33 can be opened as soon as the door zone sensor 31 detects the zone flag 29.

[0037] In the example described, in each case exactly one door zone is defined per stopping point 9, 11, 13. Alternatively, it is also known to define multiple door zones per stopping point. For example, a first door zone can be defined for the adjustment movement and a second door zone for the movement to a stopping point.

[0038] For safety reasons, it is necessary that the lift car 3 does not leave the door zone with the lift car door 33 open. In addition, impermissible accelerations and/or speeds of the lift car 3 must be prevented within the to door zone. This is carried out by means of the safety device. The safety device comprises an evaluation unit 35, which is formed by the lift control system 27 and the control device 17. Lift control system 27 and controller 17 are connected to each other by means of a signal connection (bidirectional electric connection) for this purpose. If the lift control system 27 receives from the door zone sensor 31 the signal that the lift car 3 is leaving the door zone, and if the lift control system 27 simultaneously receives from the door sensors 37 and/or 39 the signal that at least one door leaf is not closed, then the evaluation device 35 generates a control signal, on the basis of which the lift car 3 is braked. For this purpose, the evaluation device 35 has a signal connection to the operating brake 25 and the drive device 5. The zone flag 29, the door zone sensor 31 and the door sensors 37, 39 are thus part of the measuring device 45 for monitoring the lift car state.

[0039] The consequence of the control signal is that the operating brake 25 is activated and, in addition, that the drive motor 15 is switched off. It is likewise possible that the control signal merely activates the operating brake 25 or merely switches off the drive motor 15. Other known braking methods for a lift car 3 on the basis of the control signal are likewise possible.

[0040] FIG. 2 shows an illustration of the shaft head 47 of a lift shaft 7. The lift car 3 is located in the lift shaft 7. The lift car 3 can be moved in the lift shaft 7 along the guide rails 57. In the operating mode illustrated in FIG. 2, the lift car 3 is carrying out an inspection run. Arranged on the lift car 7 is an emergency limit switch cam 49. As it moves into the lift head 47, the emergency limit switch cam 49 trips the safety switch 51, which is connected to the shaft wall in the shaft head 47. The safety switch 51 is part of a safety circuit which is connected to the evaluation device 35. On the basis of the tripping of the safety switch 51, the evaluation device 35 generates the control signal, on the basis of which the lift car 3 is braked. This leads to a first safe zone 53, into which the lift car 3 cannot move during the inspection run, being predefined in the shaft head 47. Maintenance personnel who are located on the lift car 3 during the inspection run are thus secured against being crushed between lift car 3 and lift shaft end 59. As opposed to a normal run, during an inspection run a considerably greater safety margin above the lift car roof must be ensured, since maintenance personnel can be located on the lift car roof. Here, however, it is necessary to take into account the fact that the lift car still travels a certain stopping travel 55 between the tripping of the safety switch 51 and the complete standstill of the lift car 3. In order to be able to reliably prevent crushing of maintenance personnel, the length of the stopping travel 55 must be known exactly and also reproducible. All the components which influence the length of the stopping travel 55 must be determined and checked exactly. To some extent, special tripping or separate certification of the components is also required for this purpose. This relates in particular to the evaluation device 35 and all the components which contribute to the braking of the lift car 3 (in the above example, these are the operating brake 25, the drive motor 15 and the signal connection to said components). According to the invention, the evaluation device 35 generates the same control signal with which the lift car 3 is also braked when travelling with open door leaves outside a door zone. This has the advantage that the same components which, for safety reasons, are subjected to a special check or separate certification can be used for two fundamentally different applications. In this way, the number of specially checked components can be kept lower.

[0041] FIG. 3 shows the same shaft head 47 during a normal run of the lift car 3. As compared with the illustration in FIG. 2, the emergency limit switch cam 49 is offset downward in the vertical direction in relation to the lift car 3. The emergency limit switch cam 49 and the safety switch 51 thus have a second position relative to each other. In this second position, the lift car 3 can move substantially further into the lift head 47 and therefore into the first safe zone without effecting any tripping of the safety switch 51. The distance between lift car 3 and lift shaft end 59 is considerably lower than in the illustration according to FIG. 2. The end position of the lift car 3 is in this case ensured by an additional mechanism. Here, this can be, for example, a known limit switch on the counterweight buffer. The safety circuit with the safety switch 51 is thus inactive.

[0042] In order to prevent the emergency limit switch cam 49 from inadvertently leaving the first position during an inspection run, so that movement into the first safe zone 53 can no longer be safely prevented, the safety circuit has a switch 61 which continuously monitors the position of the emergency limit switch cam 49. In the event of a displacement of the emergency limit switch cam 49, the evaluation device 35 generates a control signal, on the basis of which the lift car 3 is braked, on account of the tripping of the switch 61.

[0043] Before the start of an inspection run, the maintenance personnel go onto the roof of the lift car 3 and move the emergency limit switch cam 49 from the second position into the first position. In this way, the switch 61 is put into effect, the safety circuit is activated and the lift car 3 is prevented from moving into the first safe zone. Only after activation of the safety circuit is the performance of an inspection run possible. Following the conclusion of the maintenance work, the emergency limit switch cam 49 is brought into the second position again, so that the lift car 3 can once more move into the first safe zone.

[0044] FIG. 4 shows an alternative variant of the lift system 1 during a normal run of the lift car 3. As compared with the illustration in FIG. 2, here too the emergency limit switch cam 49 is offset downward in relation to the lift car 3. Emergency limit switch cam 49 and the safety switch 51 thus have a second position relative to each other. As opposed to the variant illustrated in FIG. 3, the safety circuit is, however, also active during a normal run and defines the end position of the lift car 3 in the lift shaft 7. Consequently, no additional mechanism is needed to ensure the end position of the lift car 3. In the second position, the safety switch 51 and the emergency limit switch cam 49 predefine a second safe zone 63 in the lift shaft by means of their position relative to each other, so that the lift car 3 is prevented from moving into the second safe zone 63 during a normal run by tripping the safety switch 51. Here, the first safe zone 53 has a vertical extent which is greater than the vertical extent of the second safe zone 63, as can be seen clearly by means of a comparison of FIGS. 2 and 4. The same emergency limit switch cam 49 which prevents the lift car 3 from moving into the first safe zone 53 during an inspection run (FIG. 2) also prevents the lift car 3 from moving into the second safe zone 63 during a normal run (FIG. 4). In both cases, the emergency limit switch 49 trips the safety switch 51, whereupon the evaluation device 35 generates the control signal on the basis of which the lift car 3 is braked.

[0045] In a further-developed embodiment of the invention, the lift car 3 has a railing 65 on the lift car roof (likewise illustrated in FIGS. 2-4). Such a railing 65 can be absolutely necessary during an inspection run, because of building regulations. The railing 65 can, for example, be designed to be foldable, so that it is folded out only during an inspection run, or can be designed to be variable in height, as illustrated in FIGS. 2-4. During an inspection run (FIG. 2), the railing 65 is in a first position, and thus prevents the maintenance personnel from moving too close to the edge of the lift car roof, and thus ensures that they do not fall off. During a normal run (FIG. 3 or FIG. 4), the railing 65 is in a second position, in which it has a considerably lower vertical extent. Therefore, the lift car can move considerably further into the lift head than would be possible with the railing in the first position.

[0046] In order to prevent the railing 65 from inadvertently leaving the first position during an inspection run, so that the safety of the maintenance personnel can no longer be adequately ensured, the safety circuit has a circuit 67 which continuously monitors the position of the railing 65. In the event of a displacement of the railing 65, the evaluation device 35 generates a control signal, on the basis of which the lift car 3 is braked, on account of the tripping of the switch 67.

[0047] Before the start of an inspection run, the maintenance personnel go onto the roof of the lift car 3 and move the railing 65 from the second position into the first position. In this way, the switch 67 is tripped, the safety circuit activated and the lift car 3 is prevented from moving into the first safe zone 53. Only after the safety circuit has been activated is the performance of an inspection run possible. Following the conclusion of the maintenance work, the railing 65 is brought into the second position again, so that the lift car 3 can once more move into the first safe zone.

LIST OF DESIGNATIONS

[0048] Lift system 1 [0049] Lift car 3 [0050] Drive device 5 [0051] Lift shaft 7 [0052] Stopping point 9 [0053] Stopping point 11 [0054] Stopping point 13 [0055] Drive motor 15 [0056] Controller 17 [0057] Drive pulley 19 [0058] Cable 21 [0059] Counterweight 23 [0060] Operating brake 25 [0061] Lift control system 27 [0062] Zone flag 29 [0063] Door zone sensor [0064] Lift car door 33 [0065] Evaluation device 35 [0066] Door sensor 37 [0067] Door sensor 39 [0068] Door leaf 41 [0069] Door leaf 43 [0070] Measuring device 45 [0071] Shaft head 47 [0072] Emergency limit switch cam 49 [0073] Safety switch 51 [0074] First safe zone 53 [0075] Stopping travel 55 [0076] Guide rail 57 [0077] Shaft end 59 [0078] Switch 61 [0079] Second safe zone [0080] Switch 67