ELEVATOR SYSTEM COMPRISING AT LEAST TWO ELEVATOR CARS THAT CAN TRAVEL ALONG A COMMON RAIL SECTION

Abstract

An elevator system may include at least two elevator cars that are movable along a common rail section on a wall. The common rail section may comprise a plurality of rail segments arranged consecutively along a direction of travel of the elevator cars. Furthermore, the rail section may comprise at least one first rotary segment. A first rail segment of the plurality of rail segments may be arranged adjacent to the first rotary segment. The first rail segment may be fixed to the wall via a first fixed bearing such that the first rail segment is fixed in all three directions in space with respect to the wall. The first fixed bearing may be positioned at an end of the first rail segment that faces the first rotary segment.

Claims

1.-15. (canceled)

16. An elevator system comprising: a first elevator car; a second elevator car; and a rail section disposed on a wall, wherein the first and second elevator cars are movable along the rail section, wherein the rail section comprises: rail segments that are disposed consecutively in a direction of travel of the first and second elevator cars, wherein a first rail segment of the rail segments is fixed to the wall via a first fixed bearing, and a rotary segment adjacent to the first rail segment, wherein the first fixed bearing is disposed at an end of the first rail segment that faces the first rotary segment.

17. The elevator system of claim 16 wherein a second rail segment of the rail segments is adjacent to the first rail segment, the second rail segment being fixed to the wall via a second fixed bearing, wherein the first rail segment is spaced apart from the second rail segment to permit the first rail segment to thermally expand towards the second rail segment.

18. The elevator system of claim 17 wherein the second fixed bearing is disposed at an end of the second rail segment that faces away from the first rail segment so as to permit the first rail segment and the second rail segment to thermally expand toward each other.

19. The elevator system of claim 18 wherein the rail section comprises a second rotary segment, wherein the second rail segment is adjacent to the second rotary segment, wherein the first rail segment and the second rail segment are disposed between the first rotary segment and the second rotary segment, wherein the second fixed bearing is disposed at an end of the second rail segment that faces the second rotary segment.

20. The elevator system of claim 17 wherein a plurality of rail segments are disposed between the first rail segment and the second rail segment.

21. The elevator system of claim 16 wherein at least one of the first rail segment or the second rail segment comprises a plurality of rail elements that are disposed consecutively along the direction of travel.

22. The elevator system of claim 16 wherein the first and second elevator cars each comprise a braking device that acts on the rail segment with which the respective elevator car is engaged when the braking device is activated, wherein an acceleration force that occurs during braking of the respective elevator car is introduced into the rail segment with which the respective elevator car is engaged.

23. The elevator system of claim 16 comprising a linear drive for driving the first and second elevator cars, the linear drive comprising: primary parts that are connected to the rail segments, and secondary parts that are connected to the first and second elevator cars, wherein an acceleration force that occurs during acceleration or braking of the first or second elevator car by way of the linear drive acts on the respective rail segment with which the first or second elevator car is engaged during the acceleration or the braking.

24. The elevator system of claim 23 wherein the first and second elevator cars each comprise a braking device that acts on the rail segment with which the respective elevator car is engaged when the braking device is activated, wherein an acceleration force that occurs during braking of the respective elevator car is introduced into the rail segment with which the respective elevator car is engaged, wherein the first and second elevator cars are engaged with the rail segments such that a weight force of each of the first and second elevator cars acts via the linear drive or via the braking device on the respective rail segment with which the first or second elevator car is engaged.

25. An elevator system comprising: a first elevator car; a second elevator car; a rail section along which the first and second elevator cars are movable, wherein the rail section comprises rail segments that are disposed consecutively along a direction of travel of the first and second elevator cars; and a control system for controlling movement of the first and second elevator cars, the control system configured to control the first and second elevator cars such that a sum of forces attributable to the first and second elevator cars, when the first and second elevator cars are simultaneously engaged with one of the rail segments and when the sum of forces acts on the one of the rail segments, is smaller than a predetermined threshold value.

26. The elevator system of claim 25 comprising a sensor for determining the loading of the first and second elevator cars, wherein the control system is configured to determine maximum forces of the first and second elevator cars via a sensor signal of the sensor.

27. The elevator system of claim 25 wherein the predetermined threshold value is 2% less than a maximal permitted load of a fixed bearing of a rail element.

28. The elevator system of claim 25 wherein during normal operation of the elevator system the control system is configured to control the first and second elevator cars such that only one of the first or second elevator cars travels on each of the rail segments at a time.

29. The elevator system of claim 28 wherein a maximum force attributable to the first or second elevator car and exerted on one of the rail segments is less than the predetermined threshold value.

Description

[0034] The invention is explained in more detail below with reference to the figures, in which, in each case schematically,

[0035] FIG. 1 shows an elevator system according to the invention;

[0036] FIG. 2 shows a rail segment with a fixed bearing and a movable bearing;

[0037] FIG. 3a shows a travel curve of an upwardly moving elevator car;

[0038] FIG. 3b shows a force profile of the upwardly moving elevator car;

[0039] FIG. 3c shows the force profile during an emergency stop of the upwardly moving elevator car;

[0040] FIG. 3d shows the profile of the maximum force of the upwardly moving elevator car;

[0041] FIG. 4a shows a travel curve of a downwardly moving elevator car;

[0042] FIG. 4b shows a force profile of the downwardly moving elevator car;

[0043] FIG. 4c shows the force profile during an emergency stop of the downwardly moving elevator car;

[0044] FIG. 4d shows the profile of the maximum force of the downwardly moving elevator car;

[0045] FIG. 5 shows the profile of the maximum force of two elevator cars which are in engagement with the same rail segment.

[0046] FIG. 1 is a schematic illustration of an elevator system 11 according to the invention. The elevator system 11 comprises a first rail section 13 and a second rail section 15. The rail sections 13 and 15 are arranged on a wall 17. The elevator system 11 here comprises four elevator cars 19, 21, 23 and 25 which are movable along the two rail sections 13 and 15. Each elevator car comprises guide rollers 26 which roll on the rail section during the movement of the elevator car. In the situation illustrated, the elevator cars 19 and 21 are in engagement with the first rail section 13 and the elevator cars 23 and 25 with the second rail section 15. The first rail section 13 comprises a first rotary segment 27 and a second rotary segment 29. The second rail section 15 comprises a first rotary segment 31 and a second rotary segment 33. The elevator cars 19, 21, 23, 25 can be moved between the two rail sections 13, 15 with the aid of the rotary segments 27, 29, 31, 33. For example, for this purpose, the elevator car 21 is moved onto the rotary segment 27. Subsequently, the rotary segment 27 is rotated from a vertical alignment into a horizontal alignment. At the same time, the adjacent rotary segment 31 is likewise rotated into a horizontal alignment. In the situation shown, the rotary segment 31 has already been brought into the horizontal alignment while the rotary segment 27 has still remained in the vertical alignment. The two rotary segments 27 and 31 now form a horizontal rail section together with the compensating rail element 35. The elevator car 21 is then moved along the two rotary segments and 27 and 31 which are now aligned with each other. Since the elevator car 21 is in engagement with the rotary segment 31, the two rotary segment 27 and 31 are again brought into the vertical alignment. The elevator car 21 has therefore changed from the first rail section 13 to the second rail section 15. The further elevator cars 19, 23, 25 can be transferred between the two rail sections in a corresponding manner. A detailed description of the transfer method is found in WO 2015/144781.

[0047] In addition to the first rotary segment 27 and the second rotary segment 29, the first rail section 13 comprises a plurality of rail segments 37, 39, 41 which are arranged one behind another along the direction of travel 43. The first rail segment 37 of the plurality of rail segments is arranged here adjacent to the first rotary segment 27. The first rail segment 37 is fixed here to the wall 17 via a first fixed bearing 45. The first fixed bearing 45 is arranged at that end of the first rail segment 37 which faces the first rotary segment 27. It is thereby ensured that the distance between the first rotary segment 27 and the first rail segment 37 is fixed and only minimally changes due to thermal stresses. This is required in order to ensure that the rotation of the first rotary segment 27 is not impaired by the first rail segment 37 thermally expanding. In order to ensure the rotatability of the first rotatory segment 27, there has to be a well defined gap 57 between the first rotary segment and the adjacent rail segment. Too narrow a gap 57 would lead to the first rotary segment 27 no longer being able to rotate. On the other hand, too large a gap will lead to the guide rollers 26 of the elevator cars no longer rolling in a well defined manner when traveling over the gap 57. In particular, the formation of noise or vibrations may occur when the guide rollers 26 roll over too wide a gap 57. This reduces the travel comfort and also leads to greater wear of the guide rollers 26. Consequently, the width of the gap 57 has to remain virtually constant during the operation of the elevator system 11. This is achieved in that the rail segment 37 adjacent to the first rotary segment 27 is fixed to the wall 17 via a first fixed bearing 45, wherein the first fixed bearing 45 is arranged at that end of the first rail segment 37 which faces the first rotary segment 27. The first fixed bearing 45 therefore forms a fixed point for the first rail segment 37. The distance between the first rotary segment 27 and the first fixed bearing 45 remains constant. As a result of the fact that the first fixed bearing 45 is arranged at the facing end of the first rail segment 37, an excessive thermal expansion of the rail portion lying between the first fixed bearing 45 and the closest rotary segment also does not occur. A second rail segment 39 of the plurality of rail segments is arranged adjacent to the first rail segment 37. The second rail segment is fixed here to the wall 17 via a second fixed bearing 47. The first rail segment 37 here is at a distance 49 from the second rail segment 39, and therefore the first rail segment 37 can thermally expand in the direction of the second rail segment 39. The second fixed bearing 47 is arranged at that end of the second rail segment which faces away from the first rail segment 37. Accordingly, the first rail segment 37 and the second rail segment 39 can therefore thermally expand toward each other. In addition to the fixed bearings 45 and 47 mentioned, the rail segments 37 and 39 are additionally fastened to the wall 17 by means of movable bearings 51. Movable bearings 51 fix the rail segments only perpendicularly to the direction of travel 43 and permit free displacement in the direction of travel 43. Force therefore cannot be introduced into the wall 17 parallel to the direction of travel 43 via the movable bearings 51. The first rail segment 37 is fastened to the wall 17, for example, with the aid of a total of three movable bearings 51 and the first fixed bearing 45. By contrast, the second rail segment 39 is fastened to the wall 17 only by means of one movable bearing 51 and the second fixed bearing 47. The number of required movable bearings 51 depends here on the length of the rail segment. The design and the manner of operation of the fixed bearings 45, 46 and 47 and the movable bearings 51 will be explained in more detail below with respect to FIG. 2. In particular, at least one movable bearing is arranged at that end of the rail segment which lies opposite the fixed bearing. The first rail segment 37 is thus fastened to the wall 17 by means of a movable bearing 51, wherein the movable bearing 51 is arranged at that end of the first rail segment which lies opposite the fixed bearing 45. Two further movable bearings 51 are arranged in the central region of the first rail segment 37 and fasten the first rail segment 37 to the wall 17. The second rail segment 39 is likewise fastened to the wall 17 by means of a movable bearing 51, wherein the movable bearing 51 is arranged at that end of the second rail segment 39 which lies opposite the fixed bearing 47.

[0048] The rail segments can be formed integrally or can be composed of a plurality of rail elements. The first rail segment 37 thus comprises, for example, two rail elements 58 which are arranged one behind the other along the direction of travel 43. The individual rail elements of a rail segment are fixedly connected to one another at least in the direction of travel 43. The first rail segment 37 is therefore subject as a whole to thermal expansion in the direction of travel 43.

[0049] The first rail section 13 furthermore comprises a second rotary segment 29. The second rail segment 39 is arranged adjacent to the second rotary segment 29. The first rail segment 37 and the second rail segment 39 are therefore arranged between the first rotary segment 27 and the second rotary segment 29. The second rail segment is fixed to the wall 17 via a second fixed bearing 47, wherein the second fixed bearing 47 is arranged at that end of the second rail segment which faces the second rotary segment 29. The first rail segment, which is fixed to the wall 17 by means of the first fixed bearing 45, is therefore adjacent to the first rotary segment 27. The second rail segment 39, which is fixed to the wall 17 by means of the second fixed bearing 47, is adjacent to the second rotary segment 29. The two fixed bearings 45, 47 are arranged close to the closest rotary segment, and therefore the width of the two gaps 57 between the rotary segment and adjacent rail segment remain substantially constant. By contrast, in the event of thermal expansion of the first rail segment 37 and of the second rail segment 39, the distance 49 of the two rails segments from each other changes. This leads of course also to noises and/or vibrations when the guide rollers 26 of an elevator car change from the first rail segment 37 onto the second rail segment 39. However, in contrast to rotary segments, in the case of such fixed rail segments, corresponding measures for compensating this are known. See in this respect, for example, WO 2016/113434.

[0050] In addition to the third rotary segment 31 and the fourth rotary segment 33, the second rail section 15 comprises a plurality of rail segments 59. Each rail segment 59 is fastened to the wall 17 by means of a fixed bearing 61 and a movable bearing 51. The movable bearing 51 is in each case arranged here at that end of the rail segment 59 which lies opposite the fixed bearing 61. In the case of the rail segments 59 which are arranged adjacent to the rotary segments 31 and 33, the fixed bearings 61 are each arranged at that end of the rail segment which faces the adjacent rotary segment.

[0051] The elevator system 11 furthermore comprises a linear drive 62 for driving the elevator cars 19, 21, 23 and 25. The linear drive 62 comprises a plurality of primary parts 63 which are connected to the rail segments 37, 39, 41 and 59. Further primary parts 63 are connected to the rotary segments 24, 29, 31 and 33 and to the compensating rail elements 35. Furthermore, the linear drive comprises a plurality of secondary parts 65 which are each connected to the elevator cars 19, 21, 23 and 25. If, for example, the elevator car 21 is now accelerated by means of the linear drive 62, a force acts on the elevator car 21 and the corresponding counterforce (acceleration force) acts on the first rail segment 37, with which the elevator car 21 is in engagement during the accelerating. The same applies to the other elevator cars 19, 23 and 25. In principle, the acceleration force occurring during the acceleration of the elevator car by means of the linear drive acts on that particular rail segment with which the corresponding elevator car is in engagement during the accelerating. By appropriate activation of the linear drive 62, the latter can also be used for braking the elevator cars. In this case too, a force then acts on the elevator car and the corresponding counterforce (acceleration force) acts on the rail segment, with which the elevator car is in engagement during the braking. In the case of the elevator car 21, the two forces act first of all on the primary part 63, which is connected to the rail segment 37. The force is transmitted from the primary part 63 to the rail segment 37 and is introduced from there into the wall 17 via the first fixed bearing 45. Since the acceleration force runs parallel to the direction of travel 43 and the movable bearings 51 permit free displacement parallel to the direction of travel 43, the acceleration force is transmitted exclusively via the first fixed bearing 45.

[0052] In addition, each of the elevators cars 19, 21, 23 and 25 has a braking device 67. The braking device 67 is, for example, a shoe brake in which brake shoes are brought into contact with the rail segments for the braking. The braking device 67 therefore acts on that particular rail segment with which the corresponding elevator car is in engagement when the braking device 67 is activated. In the case of the elevator car 21, this is, for example, the first rail segment 37. During braking of the elevator car 21, the acceleration force which occurs is therefore introduced into the first rail segment 37. Since the acceleration force runs parallel to the direction of travel 43 and the movable bearings 51 permit free displacement parallel to the direction of travel 43, the acceleration force which occurs during braking by the braking device 67 is therefore transmitted exclusively via the first fixed bearing 45.

[0053] Since the elevator cars 19, 21, 23 and 25 are not connected to a counterweight via a suspension rope, as in conventional elevator systems, the weight force of the elevator cars has to be introduced into the rail segments in some way or other. While an elevator car stops, for example, at a stop, the braking device 67 is activated and thus keeps the elevator car in its position. The weight force of the elevator car therefore acts via the braking device 67 of the elevator car on that particular rail segment with which the corresponding elevator car is in engagement. When the elevator car starts up, the braking device 67 is deactivated. The weight force of the elevator car is then absorbed by the linear drive 62. In a manner corresponding to the explanation with respect to the acceleration force, the weight force first of all acts on the primary part 63. The force is transmitted from the primary part 63 to the rail segment, with which the corresponding elevator car is in engagement. As a result, the weight force therefore acts in both cases (linear drive, braking device) on that particular rail segment with which the corresponding elevator car is in engagement.

[0054] FIG. 2 shows a rail segment 41 with a fixed bearing 47 and a movable bearing 51. In the right region of FIG. 2, there is a respective cross section through the rail segment 41 in the region of the fixed bearing 47 (lower illustration) and in the region of the movable bearing 51 (upper illustration). The fixed bearing 47 comprises a first holder 53 which firstly is connected fixedly to the rail segment 41 and secondly is connectable (for example screwable) fixedly to the wall 17. The movable bearing 51 comprises a second holder 55 which is fixedly connected to the rail segment 41. The second holder 55 is accommodated in a form-fitting manner by a mounting 56 in which the second holder 56 is movable only in one direction (perpendicularly to the plane of the drawing). After the installation, this direction corresponds to the direction in which the rail segment 41 can expand freely thermally, i.e. the direction of travel 43. The mounting 56 is in turn fixedly connectable to the shaft wall 17.

[0055] FIG. 3a illustrates the travel curve of an upwardly moving elevator car. The time t is illustrated on the x axis and the speed v on the y axis. At the time t<t.sub.1, the elevator car stops at a stop, and therefore the speed is v=0. At the time t.sub.1, the elevator car is accelerated until the travel speed v=v.sub.0 is reached at the time t.sub.2. This speed is maintained by the elevator car until the braking begins at the time t.sub.3, and therefore the speed is reduced. At the time t.sub.4, the elevator car comes again to a standstill.

[0056] It is assumed for the description below that the rail segments are provided with the primary part of the linear motor. This leads to all of the forces which the linear motor acts on the elevator car resulting in corresponding counterforces which are introduced into the rail segments. In the event that the primary parts and rail segments are fixed independently of one another to the wall by means of fixed bearings, the corresponding reasoning in each case applies.

[0057] The force curves illustrated below (FIGS. 3b, 3c, 3d, 4b, 4c, 4d) each show the profile of the forces which are introduced into the rail segments. Since the elevator car is supported on the rail segments, these are always the counter forces to the forces which act on the elevator car.

[0058] FIG. 3b shows the forces which actually occur in the case of the travel curve according to FIG. 3a and are introduced into the rail segments. The time t is illustrated on the x axis and the force F on the y axis. At the time t<t.sub.1, the elevator car stops at a stop, and therefore the weight force G is in effect. During the acceleration phase t.sub.1<t<t.sub.2, an acceleration force is in effect in addition to the weight force until the elevator car has reached its travel speed. During the travel at a constant speed at the time t.sub.2<t<t.sub.3, only the weight force is again in effect. Frictional forces are ignored in this view. During the braking phase t.sub.3<t<t.sub.4, an acceleration force is in effect which is directed counter to the weight force, and therefore the force which is introduced into the rail elements is reduced in sum.

[0059] FIG. 3c shows the forces which would occur if the elevator car carries out an emergency stop at a time t. The elevator car is in the travel state here corresponding to the travel curve according to FIG. 3a. No additional forces occur at the times t<t.sub.1 and t>t.sub.4 since the elevator car is in any case stationary. At the time t.sub.1<t<t.sub.3, the elevator car moves at the constant travel speed vo. In order to brake the elevator car as rapidly as possible, a force F.sub.Em (emergency) is required which in this case is directed counter to the weight force. The force GF.sub.Em would therefore act on the rail element. Since the required emergency stopping force F.sub.Em depends on the current speed, a continuous transition is produced in the regions t.sub.1<t<t.sub.2 and t.sub.3<t<t.sub.4.

[0060] FIG. 3d shows the maximum force of the elevator car having the travel curve according to FIG. 3a. The maximum force at a time t is defined as the maximum of the force actually introduced into the rail segment at this time and the force introduced at this time during an emergency stopi.e. the maximum of the curve according to FIG. 3b and FIG. 3c. In this case of an upwardly moving elevator car, the maximum is given by the curve according to FIG. 3b, and therefore FIG. 3b and FIG. 3d are identical.

[0061] FIG. 4a illustrates the travel curve of a downwardly moving elevator car. The time t is also illustrated here on the x axis and the speed v on the y axis. At the time t<t.sub.1, the elevator car stops at a stop, and therefore the speed is v=0. At the time t.sub.1, the elevator car is accelerated until the travel speed v=v.sub.0 is reached at the time t.sub.2. The speed v.sub.0 is negative here since the elevator car is moving downward. This speed is maintained by the elevator car until the braking begins at the time t.sub.3, and therefore the amount of the speed is reduced. At the time t.sub.4, the elevator car has come again to a standstill.

[0062] FIG. 4b shows the forces which actually occur during the travel curve according to FIG. 4a and are introduced into the rail segments. The time t is illustrated on the x axis and the force F on the y axis. At the time t<t.sub.1, the elevator car stops at a stop, and therefore the weight force G is in effect. During the acceleration phase t.sub.1<t<t.sub.2, in addition to the weight force an acceleration force is in effect until the elevator car has reached its travel speed. However, the acceleration force is directed counter to the weight force, and therefore a lower force in total is introduced into the rail elements. During the travel at a constant speed at the time t.sub.2<t<t.sub.3, only the weight force is again in effect. Frictional forces are ignored in this view. During the braking phase t.sub.3<t<t.sub.4, an acceleration force is in effect which is directed in the same direction as the weight force, and therefore the force which is introduced into the rail elements is increased in sum.

[0063] FIG. 4c shows the forces which would occur if the elevator car carries out an emergency stop at a time t. The elevator car here is in the travel state corresponding to the travel curve according to FIG. 4a. At the times t<t.sub.1 and t>t.sub.4, no additional forces occur since the elevator car is in any case stationary. At the time t.sub.1<t<t.sub.3, the elevator car moves at the constant travel speed v.sub.0. In order to brake the elevator car as rapidly as possible, a force F.sub.Em is required which in this case is directed in the same direction as the weight force. G+F.sub.Em would therefore act as the force on the rail elements. Since the required emergency stopping force F.sub.Em depends on the current speed, a continuous transition is produced in the regions t.sub.1<t<t.sub.2 and t.sub.3<t<t.sub.4.

[0064] FIG. 4d shows the maximum force of the elevator car having the travel curve according to FIG. 4a. The maximum force at a time t is defined as the maximum of the force actually introduced into the rail segment at this time and the force introduced at this time during an emergency stopi.e. the maximum of the curve according to FIG. 4b and FIG. 4c.

[0065] FIG. 5 shows the profile of the maximum force of two elevator cars which are in engagement with the same rail segment. A first elevator car is fully loaded and therefore has the weight force G.sub.1 which is higher than the weight force G.sub.2 of a second elevator car. The first elevator car stops up to a time t=t.sub.1 at a stop and then moves upward until it comes again to a standstill at a stop at the time t=t.sub.4. The maximum force therefore proceeds as explained with respect to FIG. 3d. The corresponding curve is denoted by 69 in FIG. 5. A second elevator car has the weight force G.sub.2 and begins a downward travel at the time t=t.sub.5. At the time t.sub.6, it has reached the travel speed and, at the time t.sub.7, begins braking until it has come to a standstill again at the time t=t.sub.8. The curve of the maximum force 71 of said elevator car therefore behaves in a manner corresponding to the explanation with regard to FIG. 4d. The sum of the maximum forces of the two elevator cars therefore has the profile denoted by 73. FIG. 5 clearly shows that the two elevator cars are controlled in such a manner that the sum of the maximum forces of the two elevator cars is smaller at each time than a predetermined threshold value F.sub.threshold. The control system 75 designed for this purpose is illustrated in FIG. 1. If, by contrast, the first elevator car were not fully loaded, and had a weight force corresponding to the weight force of the second elevator car, there would still be sufficient clearance as far as the predetermined threshold value, and therefore a third elevator car could also move into the rail segment. If, by contrast, the threshold value F.sub.threshold is lower, the control system controls the elevator cars in such a manner that, during the normal operation of the elevator system, each rail segment is always only traveled along by precisely one elevator car. As explained previously, for example, the number of elevator cars which can move simultaneously into a rail segment depends on the weight force of the elevator cars. The elevator cars 19, 21, 23 and 25 illustrated in FIG. 1 therefore have a sensor 77 which measures the loading of the elevator cars and transmits the measurement to the control system 75. The control system 75 is designed to determine the maximum forces of all of the elevator cars with the aid of the sensor signal of the sensor 77 and the travel curves (FIG. 3a, FIG. 4a) predetermined by the control system 75.

[0066] It has been explained in conjunction with FIG. 1 that the forces acting on a rail segment are introduced into the wall 17 via precisely one fixed bearing. The predetermined threshold value is therefore predetermined as being 10%, in particular 20%, lower than the maximally permissible load of said fixed bearing. The control system 75 then ensures with the aid of the above-described control method that the load of the fixed bearing is never exceeded and also a sufficient safety margin remains. It is thereby ensured that safe operation of the elevator system is made possible while at the same time the rail sections are used efficiently by the elevator cars being able to travel closely to one another.

LIST OF REFERENCE SIGNS

[0067] 11 elevator system

[0068] 13 first rail section

[0069] 15 second rail section

[0070] 17 wall

[0071] 19 elevator car

[0072] 21 elevator car

[0073] 23 elevator car

[0074] 25 elevator car

[0075] 26 guide rollers

[0076] 27 first rotary segment

[0077] 29 second rotary segment

[0078] 31 third rotary segment

[0079] 33 fourth rotary segment

[0080] 35 compensating rail element

[0081] 37 first rail segment

[0082] 39 second rail segment

[0083] 41 rail segment

[0084] 43 direction of travel

[0085] 45 first fixed bearing

[0086] 47 second fixed bearing

[0087] 49 distance

[0088] 51 movable bearing

[0089] 53 first holder

[0090] 55 second holder

[0091] 56 mounting

[0092] 57 gap

[0093] 58 rail element

[0094] 59 rail segment

[0095] 61 fixed bearing

[0096] 62 linear drive

[0097] 63 primary parts

[0098] 65 secondary parts

[0099] 67 braking device

[0100] 69 maximum force curve of first elevator car

[0101] 71 maximum force curve of second elevator car

[0102] 73 sum of the maximum force curves of the two elevator cars

[0103] 75 control system

[0104] 77 sensor