Patent Publication Number: US-9834410-B2

Title: Elevator installation

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. National Stage Entry of International Patent Application Serial Number PCT/EP2014/002638, filed Sep. 29, 2014, which claims priority to German patent application no. 102013110792.3, filed Sep. 30, 2013. 
     FIELD 
     The present disclosure relates to an elevator installation. 
     BACKGROUND 
     In order to convey a multiplicity of individuals within a short time by means of an elevator installation, it is known from international laid-open application WO 2004/048243 A1 to arrange at least two elevator cars one above another in a shaft and to move same upward and downward vertically separately from each other. Each elevator car is assigned a driving device with a drive pulley, with the aid of which the elevator car can be driven. The two elevator cars can be moved upward and downward along a common track in the shaft. 
     The two elevator cars are each connected to a counterweight via a rope or belt arrangement. At least one rope or belt arrangement here has two rope or belt sections via which one of the two elevator cars is coupled to the counterweight thereof and which run along at least one side of the other elevator car. For example, provision may be made for the second elevator car, which is arranged below the first elevator car, to be suspended on two supporting rope or supporting belt sections via which the second elevator car is coupled to the second counterweight and which extend upward vertically from the second elevator car and each run along a side of the first elevator car, and therefore the first elevator car is positioned between the two supporting rope or supporting belt sections of the second elevator car. 
     Elevator installations with two elevator cars which are arranged one above another in a shaft and are movable separately from each other are used in particular in the case of very high buildings. In these cases, the rope or belt arrangements have very great lengths. In this connection, the rope or belt arrangements may be induced into oscillations which are caused, for example, by a movement of the building in which the elevator installation is installed. Building movements of this type can occur because of wind loads or, for example, also in the event of an earthquake. The oscillations lead to deflections of the rope or belt arrangements in the horizontal direction. There is the risk in this case of rope or belt sections which run laterally along an elevator car coming into contact with the elevator car. This may lead to damage to the elevator car or else of the rope or belt sections. Furthermore, the contact with the elevator car causes the production of noises which may unsettle the passengers in the elevator car. 
     Accordingly, there is a need for an elevator installation of the type discussed above which prevents or minimizes the occurrence of oscillations in the rope or belt section, which may otherwise impair the elevator car. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is described in detail below with reference to the attached drawing figures, wherein: 
         FIG. 1  is a schematic side view of an embodiment of an elevator installation of the present disclosure; 
         FIG. 2  is a simplified top cross-sectional view of the embodiment of  FIG. 1  about section line  2 - 2  in  FIG. 1 , in which a first elevator car exceeds a predetermined minimum distance from the limiting elements of two limiting members; 
         FIG. 3  is a simplified top cross-sectional view of the embodiment of  FIG. 2 , in which the first elevator car falls short of the minimum distance from the limiting elements of the two limiting members; 
         FIG. 4  is a simplified top cross-sectional view of the embodiment of  FIG. 1  about section line  4 - 4  in  FIG. 1 , in which a second elevator car exceeds a predetermined minimum distance from the limiting elements of two limiting members; and 
         FIG. 5  is a simplified top cross-sectional view of the embodiment of  FIG. 4 , in which the second elevator car falls short of a predetermined minimum distance from the limiting elements of the two limiting members. 
     
    
    
     DETAILED DESCRIPTION 
     The invention relates to an elevator installation with a shaft in which a first elevator car and a second elevator car arranged below the first elevator car are movable upward and downward in the vertical direction separately from each other, wherein the first elevator car is coupled to a first counterweight via a first rope or belt arrangement and the second elevator car is coupled to a second counterweight via a second rope or belt arrangement, and wherein at least one rope or belt arrangement has two rope or belt sections via which one of the two elevator cars is coupled to the counterweight and which run along at least one side of the other elevator car. For simplicity, it should be understood that any reference herein or in the claims to a “rope” should be understood to include both ropes and belts, as well as any other similar or known elevator suspension or hoisting member or structure, and should not otherwise be read to limit the scope of the present disclosure. 
     An elevator installation of the present disclosure limits rope or belt oscillations by the having at least one limiting member held in a predetermined position in the shaft. The at least one limiting member is assigned to a rope or belt section and has at least one limiting element, wherein the at least one limiting element is movable between a limiting position and a release position, depending on the position of the elevator car which is coupled to the counterweight via the associated rope or belt section. In the limiting position, the at least one limiting element can be positioned on that side of the associated rope or belt section which faces the elevator car that is coupled to a counterweight via the rope or belt section. In the release position, the at least one limiting element releases said side. 
     The elevator installation according to the invention has at least one limiting member, with the aid of which any oscillations of a rope or belt section assigned to the limiting member can be limited. The limiting member has at least one limiting element which is movable to and fro between a limiting position and a release position. Provision may be made for use to be made of a plurality of limiting members, wherein each rope or belt section which runs along a side of an elevator car is assigned at least one limiting member. In the limiting position, the limiting element can be positioned on that side of the associated rope or belt section which faces the elevator car coupled to a counterweight via the rope or belt section. In the release position, the at least one limiting element releases said side of the rope or belt section. 
     By positioning the at least one limiting element on that side of the rope or belt section which faces the elevator car coupled to a counterweight via the rope or belt section, a deflection of the rope or belt section in the direction of the elevator can be obstructed. In the limiting position, the at least one limiting element therefore counteracts an oscillation of the rope or belt section in the direction of the elevator car. 
     However, the elevator cars should not be impaired by the at least one limiting member as they travel past the latter. This does not constitute any problem for the elevator car which does not undergo any coupling with the counterweight thereof via the rope or belt section assigned to the limiting member, since the elevator car together with all of the components thereof can take up a sufficiently large distance from the limiting member in the horizontal direction such that a collision can be avoided even if said elevator car takes up a position at the same height as the limiting member. However, for the elevator car which is coupled to the counterweight thereof via the rope or belt section assigned to the limiting member, the problem arises that, for the securing or deflection of the rope or belt section, the elevator car may have one or more laterally protruding fastening or deflecting members which may collide with a limiting element if the elevator car is positioned at the same height as the limiting member. In order to avoid this, the at least one limiting element can take up a release position in which said limiting element releases that side of the associated rope or belt section which faces the elevator car. A collision with components of the elevator car which is coupled to the counterweight thereof via the rope or belt section assigned to the limiting member is therefore also prevented in the release position. 
     The positioning of the at least one limiting element in the limiting position and the release position takes place depending on the position of the elevator car which is coupled to the counterweight thereof via the rope or belt section assigned to the limiting member. In the release position, the at least one limiting element also takes up a distance from the elevator car which is coupled to the counterweight thereof via the rope or belt section assigned to the limiting member. A collision with said elevator car is therefore reliably avoided. So that the at least one limiting element takes up the release position thereof promptly, the movement of the limiting element takes place depending on the position of the elevator car which is coupled to the counterweight thereof via the rope or belt section assigned to the limiting member. The optional positioning of the at least one limiting element in a limiting position and a release position firstly therefore permits a limitation of deflections of a rope or belt section and, secondly, it is ensured that the at least one limiting element cannot collide with an elevator car. 
     For example, it can be provided that the second rope or belt arrangement has a supporting rope or supporting belt arrangement on which the second elevator car is suspended and which is guided around a second drive pulley arranged above the two elevator cars and couples the second elevator car to the counterweight and which has two supporting rope or supporting belt sections which extend laterally along the first elevator car, wherein each of the supporting rope or supporting belt sections is assigned at least one limiting member. In the case of such a configuration, lateral deflections of the supporting rope or supporting belt sections, in particular in the direction of the first elevator car, along which they are guided laterally, can be limited by at least one limiting element taking up the limiting position thereof. 
     In particular, it can be provided that each supporting rope or supporting belt section is assigned at least two limiting members, with the aid of which deflections of the supporting rope or supporting belt sections in the direction of the first elevator car can be limited. 
     The at least two limiting members which are assigned to a supporting rope or supporting belt section are preferably arranged distributed uniformly in the vertical direction in a shaft region which extends between the uppermost stop of the first elevator car and the lowermost stop of the second elevator car. 
     It is of advantage if each supporting rope or supporting belt section running laterally past the first elevator car is assigned at least one limiting member, wherein the at least one limiting element of the limiting member automatically takes up the limiting position thereof if the second elevator car, in a position below the limiting member, exceeds a predetermined minimum distance from said limiting member, and wherein the at least one limiting element of the limiting member automatically takes up the release position thereof if the second elevator car falls short of the predetermined minimum distance from said limiting member. In particular, it can be provided that the at least one limiting element is automatically movable into the limiting position thereof as soon as the second elevator car exceeds the predetermined minimum distance. This ensures that the limiting element limits deflections of the associated supporting rope or supporting belt section as soon as the second elevator car exceeds the predetermined minimum distance after said elevator car has moved past the limiting member during a trip downward. 
     If the second elevator car is located at a distance which is greater than the minimum distance above the at least one limiting member, which is assigned to the supporting rope or supporting belt section via which the second elevator car is coupled to the counterweight thereof, said supporting rope or supporting belt section is also located above the limiting member. In this case, it is insignificant whether the limiting element of the limiting member takes up the limiting position or release position thereof since the supporting rope or supporting belt section is not located in the engagement region of the limiting element. 
     In particular in the case of very high buildings and accordingly very long supporting rope or supporting belt arrangements, it is favorable if the weight of each supporting rope or supporting belt arrangement is compensated for by a compensating rope or compensating belt arrangement. In the case of such a configuration, each elevator car is coupled to the counterweight thereof not only via a supporting rope or supporting belt arrangement, but also via a compensating rope or compensating belt arrangement. The supporting rope or supporting belt arrangement is guided via a drive pulley which is positioned above the two elevator cars, and the compensating rope or compensating belt arrangement is guided via a rope deflection device which is positioned below the two elevator cars. The weight of the compensating rope or compensating belt arrangement compensates for the weight of the supporting rope or supporting belt arrangement. 
     In an advantageous configuration of the invention, the first rope or belt arrangement has a compensating rope or compensating belt arrangement which is guided around a rope deflecting device arranged below the two elevator cars and couples the first elevator car to the first counterweight and which has two compensating rope or compensating belt sections which extend laterally along the second elevator car, wherein each compensating rope or compensating belt section is assigned at least one limiting member. In the case of such a configuration, lateral deflections of the compensating rope or compensating belt sections can be limited, in particular in the direction of the second elevator car along which they are guided laterally, by the associated limiting elements taking up the limiting position thereof. 
     It can be provided that each compensating rope or compensating belt section is assigned at least two limiting members. The at least two limiting members are advantageously arranged distributed uniformly in a shaft region which extends between the uppermost stop of the first elevator car and the lowermost stop of the second elevator car. 
     It is of advantage if each compensating rope or compensating belt section running laterally past the second elevator car is assigned at least one limiting member, wherein the at least one limiting element of the limiting member automatically takes up the limiting position thereof if the first elevator car, in a position above the limiting member, exceeds a predetermined minimum distance from said limiting member, and wherein the at least one limiting element of the limiting member automatically takes up the release position thereof if the first elevator car falls short of the predetermined minimum distance. In particular, it can be provided that the at least one limiting element is automatically movable into the limiting position thereof as soon as the first elevator car exceeds the predetermined minimum distance. This ensures that the limiting element limits deflections of the associated compensating rope or compensating belt section as soon as the first elevator car exceeds the minimum distance after said elevator car has traveled past the limiting element during a trip upward. 
     If the first elevator car is located at a distance which is greater than the minimum distance below the at least one limiting member, which is assigned to the compensating rope or compensating belt section via which the first elevator car is coupled to the counterweight thereof, said compensating rope or compensating belt section is also located below the limiting member. In this case, it is insignificant whether the limiting element takes up the limiting position or release position thereof since the compensating rope or compensating belt section is not located in the engagement region of the limiting element. 
     In an advantageous configuration of the invention, at least one elevator car has two fastening or deflecting members which each protrude laterally over a side wall of the elevator car and to or at which a respective rope or belt section is secured or deflected, and the limiting elements of the limiting members assigned to said rope or belt sections, in the limiting position thereof, enter the region of the vertical projection of a fastening or deflecting member and, in the release position thereof, are arranged outside the vertical projection of the fastening or deflecting members. The fastening or deflecting members arranged on at least one elevator car protrude laterally outward in order to fasten a rope or belt section to said elevator car or to deflect same at said elevator car. The limiting elements of the fastening members assigned to said rope or belt sections project, in the limiting position thereof, into the region of a vertical projection of the fastening or limiting members. In order, however, to avoid damage to the fastening or deflecting members, the limiting elements only take up the limiting position if the elevator car exceeds a predetermined minimum distance from the respective limiting member. If the elevator car falls short of the minimum distance, the limiting elements take up the release position thereof in which they are arranged outside the vertical projection of the fastening or deflecting members and therefore cannot impair the fastening or deflecting members when the elevator car travels past the latter. 
     As already explained, horizontal deflections of a rope or belt section can be limited in the direction of an elevator car with the aid of the at least one limiting element. It is of particular advantage if oscillations of the rope or belt section can also be limited in other directions by means of the limiting element. In an advantageous embodiment of the elevator installation according to the invention, the at least one limiting element, in the limiting position thereof, engages behind a rope or belt section for this purpose. As a result, it can be ensured in a structurally simple manner that oscillations of the rope or belt section in the direction of an elevator car are obstructed just as oscillations are in another direction, in particular in a direction perpendicular thereto. 
     The at least one limiting member preferably has two limiting elements which, in the limiting position thereof, engage around a rope or belt section in the manner of clamps. 
     For example, it can be provided that the two limiting elements form two clamping jaws which are mounted so as to be pivotable to and fro between the release position and the limiting position. The clamping jaws can be, for example, of C- or L-shaped configuration. 
     The two clamping jaws are advantageously mounted pivotably on a bearing element which can be secured to a shaft wall. 
     The bearing element is advantageously of plate-like design. 
     The at least one limiting member preferably has a controllable motorized driving element which is coupled to a control device. The driving element can be configured, for example, as a hydraulic or pneumatic piston-cylinder unit or, for example, also as an electric motor. The at least one limiting element of the limiting member can be moved by the driving element. 
     The controllable driving element is coupled to a control device. An elevator control apparatus which controls the operation of the entire elevator installation can be used as the control device. 
     It can be provided that the elevator installation has an oscillation-limiting controller which is connected to the controllable driving element of the at least one limiting member. The oscillation-limiting controller can additionally be connected to an elevator control apparatus of the elevator installation, wherein the elevator control apparatus supplies position data of the two elevator cars to the oscillation-limiting controller. On the basis of the position data, the oscillation-limiting controller can determine the distance of the elevator cars from the at least one limiting member. If a predetermined minimum distance is fallen short of, the oscillation-limiting controller can supply a control signal to a driving element, under the action of which control signal the at least one limiting element of the limiting member is moved by the driving element into the release position thereof. If the minimum distance is exceeded, the oscillation-limiting controller can supply a control signal to the driving element, under the action of which control signal the limiting element is moved by the driving element into the limiting position thereof. 
     The drawing is a schematic illustration of an advantageous embodiment of an elevator installation according to the invention which is covered as a whole by the reference sign  10 . The elevator installation  10  comprises a shaft  12  which, in the exemplary embodiment illustrated, has a rectangular cross section with a first shaft wall  14 , a second shaft wall  16 , a third shaft wall  18  and a fourth shaft wall  20 . In addition, the shaft  12  has a shaft ceiling  22  and a shaft floor  24 . 
     In the shaft  12 , a first elevator car  26  and a second elevator car  28  are movable upward and downward in the vertical direction separately from each other along common guide rails, which are not illustrated in order to obtain better clarity in the drawing. The first elevator car  26  is arranged above the second elevator car  28 . The first elevator car  26  is assigned a first driving device with a first drive pulley  30 , and the second elevator car  28  is assigned a second driving device with a second drive pulley  32 . The two drive pulleys  30 ,  32  can each be set into rotation by a driving motor. The driving motors of the drive pulleys  30 ,  32  are connected to an elevator control apparatus  34  which controls the driving motors. 
     The first elevator car  26  is coupled to a first counterweight  36  via a first rope arrangement, and the second elevator car  28  is coupled to a second counterweight  38  via a second rope arrangement. In  FIGS. 2 to 5 , the counterweights  36  and  38  are not illustrated in order to achieve better clarity. The rope arrangements have a multiplicity of ropes. Alternatively, use could also be made of belt arrangements in which the elevator cars  26  and  28  are coupled to the counterweights  36  and  38  via a multiplicity of belts. As is explained in detail below, the rope arrangements have a plurality of rope sections which run laterally along the elevator cars  26 ,  28 . In a corresponding manner, the elevator installation  10  can also have belt arrangements with a plurality of belt sections which, in a manner corresponding to the rope sections, run along the elevator cars  26 ,  28 . For the sake of simplicity, the elevator installation  10  is explained in more detail below only with reference to the rope arrangements. However, the invention also relates in the same manner to elevator installations with belt arrangements. 
     The coupling of the first elevator car  26  to the first counterweight  36  takes place firstly via a first supporting rope arrangement  40  which is guided via the first drive pulley  30  and, secondly, via a first compensating rope arrangement  42  which runs from the first elevator car  26  in the vertical direction into the region of a shaft pit  44  and is deflected there and subsequently extends upward in the vertical direction as far as the first counterweight  36 . The first compensating rope arrangement  42  has a first rope end  46  and a second rope end  48 . The two rope ends  46 ,  48  are secured on the first counterweight  36 . The first compensating rope arrangement  42  extends from the first rope end  46  vertically downward to a first deflecting roller  50  of a rope deflecting device  45 . The first compensating rope arrangement  42  runs from the first deflecting roller  50  in the horizontal direction to a second deflecting roller  52  of the rope deflecting device  45 . The first compensating rope arrangement  42  runs from the second deflecting roller  52  upward in the vertical direction as far as a first elevator car roller  56  which is arranged on an elevator car ceiling  54  of the first elevator car  26  and from which the first compensating rope arrangement  42  is guided in the horizontal direction to a second elevator car roller  58  likewise arranged on the elevator car ceiling  54 . The first elevator car roller  56  and the second elevator car roller  58  form deflecting members and are advantageously mounted rotatably. The first compensating rope arrangement  42  extends from the second elevator car roller  58  vertically downward again into the shaft pit to a third deflecting roller  60  at which the compensating rope arrangement  42  is deflected in the horizontal direction. The third deflecting roller  60  is adjoined by a fourth deflecting roller  62  of the rope deflecting device, and the first compensating rope arrangement extends from the fourth deflecting roller  42  upward in the vertical direction as far as the second rope end  48 . Instead of on the elevator car ceiling  54 , the elevator car rollers  56 ,  58  could also be held on the elevator car floor  55  of the first elevator car. 
     In the region between the second deflecting roller  52  and the first elevator car roller  56 , the first compensating rope arrangement  42  forms a first compensating rope section  64 , and, in the region between the second elevator car roller  58  and the third deflecting roller  60  of the rope deflecting device, the first compensating rope arrangement  42  forms a second compensating rope section  66 . The second elevator car  28  is arranged between the first compensating rope section  64  and the second compensating rope section  66 , and therefore the first compensating rope section  64  and the second compensating rope section  66  extend on mutually opposite sides of the first elevator car and of the second elevator car  28 . Instead of the elevator car rollers  56 ,  58 , use could also be made of fastening members which are configured as rope suspension means and on which the compensating rope sections  64  and  66  are fixed on the upper side or lower side of the first elevator car. In the case of such a configuration, the horizontal section of the compensating rope arrangement  42  between the rope suspension means could be omitted. 
     The second elevator car  28  is coupled to the second counterweight  38  via a second supporting rope arrangement  68  and a second compensating rope arrangement  70 . The second supporting rope arrangement  68  is secured at a first rope end  72  on the shaft ceiling  22 . The second supporting rope arrangement  68  extends from the first rope end  72  vertically downward as far as a third elevator car roller  76  which is mounted rotatably on an elevator car floor  74  of the second elevator car  28  and is assigned to the third shaft wall  18 . The second supporting rope arrangement  68  extends from the third elevator car roller  76  in the horizontal direction to a fourth elevator car roller  78  which is likewise mounted rotatably on the elevator car floor  74  and is assigned to the first shaft wall  14 . The second supporting rope arrangement  68  extends from the fourth elevator car roller  78  upward in the vertical direction as far as the second drive pulley  32 , from which the second supporting rope arrangement  68 , in the exemplary embodiment illustrated, extends downward in the vertical direction as far as a counterweight roller  80  which is mounted rotatably on the second counterweight  38 . The second supporting rope arrangement  68  extends from the counterweight roller  80  upward in the vertical direction as far as a second rope end  82  of the second supporting rope arrangement  68 , which rope end is fixed on the shaft ceiling  22 . Instead of on the elevator car floor  74 , the elevator car rollers  76 ,  78  could also be held on the elevator car ceiling  75  of the second elevator car  28 . 
     In the region between the first rope end  72  and the third elevator car roller  76 , the second supporting rope arrangement  68  forms a first supporting rope section  84 , and, in the region between the fourth elevator car roller  78  and the second drive pulley  32 , the second supporting rope arrangement  68  forms a second supporting rope section  86 . The first elevator car  26 , which is arranged above the second elevator car  28 , is positioned between the first supporting rope section  84  and the second supporting rope section  86 , and therefore the two supporting rope sections  84 ,  86  extend along mutually opposite sides of the first elevator car  26  and of the second elevator car  28 . 
     The second compensating rope arrangement  70  is secured at a first rope end  88  on the elevator car floor  74  and extends downward in the vertical direction from the first rope end  88  to a fifth deflecting roller  90  of the rope deflecting device  45 . The second compensating rope arrangement  70  extends from the fifth deflecting roller  90  in the horizontal direction to a sixth deflecting roller  92  of the rope deflecting device  45 , and the second compensating rope arrangement  70  extends from the sixth deflecting roller  92  as far as a second rope end  94  of the second compensating rope arrangement  70 , which rope end is secured on the second counterweight  38 . 
     The elevator installation  10  is used in particular in the case of very high buildings, and therefore the two supporting rope sections  84 ,  86 , like the two compensating rope sections  64 ,  66 , can have a considerable length. Oscillations of the supporting rope sections  84 ,  86  and the compensating rope sections  64 ,  66  may occur, for example, because of movements of the building in which the elevator installation  10  is installed, wherein the supporting rope sections  84 ,  86  and the compensating rope sections  64 ,  66  are deflected in the horizontal direction. In order in this case to avoid the supporting rope sections  84 ,  86  or else the compensating rope sections  64 ,  66  being able to impair the elevator cars  26 ,  28  during the travel thereof, the elevator installation  10  has an oscillation-limiting device  100  with a total of eight limiting members which each have two movable limiting elements and a driving element in the form of a controllable electric motor and are connected via control lines to an oscillation-limiting controller  102  which, for its part, is connected to the elevator control apparatus  34  via a connecting line. 
     A first limiting member  104  and a second limiting member  106 , which is arranged aligned in the vertical direction and at a distance from the former, are assigned to the first supporting rope section  84  and secured on the third shaft wall  18 . A third limiting member  108  and a fourth limiting member  110 , which are arranged aligned with respect to each other in the vertical direction, are assigned to the second supporting rope section  86 . The third limiting member  108  and the fourth limiting member  110  are secured on the first shaft wall  14 . 
     The first compensating rope section  64  is assigned a fifth limiting member  112  and a sixth limiting member  114  which are secured aligned in the vertical direction and at a distance from each other on the third shaft wall  18 , and the second compensating rope section  66  is assigned a seventh limiting member  116  and an eighth limiting member  118  which are secured aligned in the vertical direction and at a distance from each other on the first shaft wall  14 . The fifth to eighth limiting members  112 ,  114 ,  116  and  118  are illustrated by dashed lines in  FIG. 1  in order to achieve better clarity. 
     Each limiting member  104  to  118  has a controllable driving element in the form of an electric motor  105  to  119 . 
     The limiting members  104  to  118  are of identical configuration. As becomes clear from  FIGS. 2 to 5 , the limiting members  104  to  118  each comprise a plate-like bearing element  122  which is securable on a shaft wall and on which a first limiting element  124  and a second limiting element  126  are each mounted so as to be pivotable about vertically oriented pivot axes. The two limiting elements  124 ,  126  are of mirror-symmetrical design with respect to each other with respect to a mirror plane oriented perpendicularly to the plate-like bearing element  122 . Said limiting elements are each configured in the manner of a clamping jaw and can be pivoted horizontally to and fro between a limiting position, which is illustrated in  FIGS. 2 and 4 , and a release position, which is illustrated in  FIGS. 3 and 5 , by means of the electric motor already explained. In the limiting position, the two limiting elements  124 ,  126  in combination with the bearing element  122  each engage around the associated rope section. In this case, the two limiting elements  124 ,  126  can be positioned in the limiting position on that side of the respective rope section which faces the elevator car which is coupled to a counterweight via the rope section. 
     The supporting rope sections  84 ,  86  via which the second elevator car  28  is coupled to the second counterweight  38  therefore cannot be deflected horizontally in the direction of the first elevator car  26 , along which they are guided laterally if the limiting members  104 ,  106 ,  108  and  110  take up the limiting position thereof. In a corresponding manner, the compensating rope sections  64 ,  66  via which the first elevator car  26  is coupled to the first counterweight  36  cannot be deflected horizontally in the direction of the second elevator car  28 , along which they are guided laterally, if the limiting members  112 ,  114 ,  116  and  118  take up the limiting position thereof. 
     The limiting elements  124 ,  126 , in the release position thereof, release that side of the rope or belt section which is assigned to the respective elevator car. This becomes clear from  FIGS. 3 and 5 . In the release position, the limiting elements  124 ,  126  are pivoted out in the direction of the shaft wall on which the respective limiting member is secured. 
     In the limiting position, the limiting elements  124 ,  126  of the limiting members  104 ,  106 ,  108  and  110  assigned to the supporting rope sections  84 ,  86  enter the region of the vertical projection of the elevator car rollers  76 ,  78  of the second elevator car  28 , whereas said limiting elements, in the release position thereof, take up a position outside the vertical projection of the elevator car rollers  76 ,  78 . In a corresponding manner, the limiting elements  124 ,  126  of the limiting members  112 ,  114 ,  116  and  118  assigned to the compensating rope sections  64 ,  66 , in the limiting position thereof, enter the region of the vertical projection of the elevator car rollers  56 ,  58 , whereas said limiting elements, in the release position thereof, take up a position outside the vertical projections of the elevator car rollers  56 ,  58 . 
     The control of the limiting members  104  to  110  assigned to the supporting rope sections  84 ,  86  takes place depending on the distances which the second elevator car  28  coupled to the second counterweight  38  via the supporting rope sections  84 ,  86  has from the limiting members  104  to  118 . In a corresponding manner, the control of the limiting members  112  to  118  assigned to the compensating rope sections  64 ,  66  takes place depending on the distances which the first elevator car  26  coupled to the first counterweight  36  via the compensating rope sections  64 ,  66  has from the limiting members  112  to  118 . For this purpose, the rope oscillation-limiting controller  102  is supplied with the position data of the two elevator cars  26 ,  28  by the elevator control apparatus  34 . On the basis of the supplied position data, the oscillation-limiting controller  102  calculates the distances which the first elevator car  26  and the second elevator car  28  have from the respective limiting members  104  to  118 . If the current distance exceeds a predetermined minimum distance, the oscillation-limiting controller controls the limiting elements  124 ,  126  of the respective limiting member  104  to  118  in such a manner that the limiting elements  124 ,  126  take up the limiting position thereof in which said limiting elements engage around the respectively associated rope or belt section. Although, in this position, the limiting elements  124 ,  126  enter the vertical projections of the laterally outwardly protruding elevator car rollers  56 ,  58 ,  76 ,  78  of the respective elevator cars  26  and  28 , since the elevator cars  26 ,  28  exceed the predetermined minimum distance there is no risk of the limiting elements  124 ,  126  colliding with the elevator cars  26 ,  28 . If, however, the current distance of the elevator cars  26 ,  28  falls short of the predetermined minimum distance, the oscillation-limiting controller  102  controls the movement of the limiting elements  124 ,  126  of the respective limiting member  104  to  118  in such a manner that the limiting elements  124 ,  126  take up the release position thereof in which said limiting elements are arranged outside the vertical projection of the elevator car rollers  56 ,  58 ,  76 ,  78 , and therefore the elevator cars  26 ,  28  can travel past the limiting members  104  to  118  without a collision. 
     By the use of the two elevator cars  26 ,  28  which can be moved upward and downward in the vertical direction separately from each other in the shaft  12 , a multiplicity of individuals can be conveyed within a short time by means of the elevator installation  10 . The compensating rope sections  64 ,  66  via which the first elevator car  26  is coupled to the first counterweight  36  are guided laterally along the second elevator car  28 , and the supporting rope sections  84 ,  86  via which the second elevator car  28  is coupled to the second counterweight  38  are guided laterally along the first elevator car  26 . In order, in the event of rope oscillations developing, to avoid the compensating rope sections  64 ,  66  being able to obstruct the second elevator car  28 , or the supporting rope sections  84 ,  86  being able to obstruct the first elevator car, use is made of the oscillation-limiting device  100  which counteracts rope oscillations of this type.