Patent Publication Number: US-7913818-B2

Title: Elevator installation in a building with at least one transfer floor

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. provisional patent application Ser. No. 60/871,879 filed Dec. 26, 2006. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an elevator installation in a building with at least one transfer floor. 
     BACKGROUND OF THE INVENTION 
     Modern elevator concepts for buildings with thirty and more floors have transfer floors which are served by an elevator installation. Such an elevator installation comprises a group of at least two elevators. A first elevator directly serves the transfer floors from an entrance lobby, i.e. passengers are coarsely distributed relatively quickly from the entrance lobby by a high-speed elevator to the different transfer floors. A second elevator carries out fine distribution of the passengers from the transfer floors to the destination floors thereof. 
     An elevator usually comprises an elevator car, which is vertically movable in a shaft and receives passengers in order to transport these to a desired floor of a building. In order to be able to look after this task the elevator usually has at least the following elevator components: a drive with a motor and a drive pulley, deflecting rollers, tension means, a counterweight as well as a respective pair of guide rails for guidance of an elevator car and a counterweight. 
     In that case the motor produces the power required for transport of the passengers present in the elevator car. An electric motor usually looks after this function. This directly or indirectly drives a drive pulley, which is in friction contact with a tension means. The tension means can be a belt or a cable. It serves for suspension as well as conveying the elevator car and the counterweight, which both are so suspended that the gravitational forces thereof act in opposite direction along the tension means. The resultant gravitational force which has to be overcome by the drive, correspondingly substantially reduces. In addition, due to the greater contact force of the tension means with the drive pulley a greater drive moment can be transmitted by the drive pulley to the tension means. The tension means is guided by deflecting rollers. 
     The optimum utilization of the shaft volume has ever increasing significance in elevator construction. Particularly in high-rise buildings with a high degree of utilization of the building a management of the passenger traffic as efficiently as possible for a given shaft volume is desired. This objective can be achieved firstly by an optimum space-saving arrangement of the elevator components, which creates space for larger elevator cars, and secondly by elevator concepts which enable vertical movement of several independent elevator cars in one shaft. 
     European patent document EP 1 526 103 shows an elevator installation with at least two elevators in a building, which is divided up into zones. A zone in that case comprises a defined number of floors which are served by an elevator. A zone is allocated to each elevator. A transfer floor is provided in order to go from one zone to another zone. At least one of the elevators has two elevator cars which are movable independently of one another vertically one above the other at two car guide rails. The arrangement of two fetch or carry cars is to assist with preventing unnecessary waiting times at the transfer floors. 
     An elevator with at least two elevator cars disposed one above the other in the same shaft is shown in European patent document EP 1 489 033. Each elevator car has an own drive and an own counterweight. The drives are arranged near first and second shaft walls and the counterweights are also respectively suspended below the associated drive at drive or holding cables near first or second shaft walls. The axes of the drive pulleys of the drives are disposed perpendicularly to first and second shaft walls. The two independently movable elevator cars ensure a high conveying performance. The positioning of the drives in the shaft near first or second walls renders a separate engine room superfluous and enables a space-saving, compact arrangement of the drive elements in the shaft head. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to further increase the conveying performance of an elevator installation for a given shaft cross-section in a building with zonal division and at least one transfer floor. 
     The elevator installation according to the present invention lies in a building with at least two elevators, wherein the building is divided into building zones and each elevator has at least one elevator car. Each elevator car is movable independently by way of an associated drive in an associated car zone. In addition, each car zone has at least one transfer floor. A first elevator has at least three elevator cars arranged vertically one above the other in a shaft. At least three of these car zones are allocated to a building zone. 
     Thanks to the at least three elevator cars, which are independently movable one above the other, of an elevator, the elevator installation has a significantly higher conveying performance. Waiting times at transfer floors are thus further reduced and the creation of waiting loops is largely avoided. 
     Advantageously this at least one elevator car of a second elevator is a multi-car with at least two cars arranged vertically one above the other. These two cars are associated with the same car zone, since they are physically connected and can thus be moved only in common. 
     The advantage of the elevator installation with a double-car resides in the doubling of the available car volume of an elevator car. Thus, up to twice as many passengers can be conveyed by one journey. 
     Advantageously the multi-car serves at least two transfer floors disposed one above the other. 
     The advantage of the elevator installation is that in the case of doubling of the transfer floors the waiting times on the respective transfer floors can be further reduced. The transfer floors have a transfer or waiting space for the transfer. In the case of a doubled number of such transfer spaces the transfer takes place substantially free of conflict and if, notwithstanding the increased conveying performance waiting times should nevertheless occur, the passengers have available twice the volume of waiting space. Staying in the transfer floors or transfer or waiting spaces is thus more pleasant in every instance. 
     Advantageously the at least three elevator cars of the first elevator have a middle and two adjacent elevator cars. The middle elevator car is in that case independently movable in a middle car zone and the two adjacent elevator cars are independently movable in two adjacent car zones. With further advantage the middle car zone overlaps adjacent car zones. 
     The advantage of the elevator installation with such overlapping car zones is that passengers can, at any desired floor which lies in the region of overlap of the car zones, transfer from a middle car zone to an adjacent car zone. This enables a more flexible conduct of the passengers. In addition, floors in the overlap region of the car zones are served by two elevator cars and thus the conveying performance of the elevator installation is increased. 
     Advantageously the at least three drives associated with the elevator cars can be moved past by the elevator cars. 
     The elevator installation has the advantage that the drives can be arranged in space-saving and flexible manner in the shaft without coming into conflict with the elevator cars. 
     Advantageously the at least three drives associated with the elevator cars are positioned at a first shaft wall or a second, opposite shaft wall. 
     The advantage of the elevator installation resides in the position of the drives between elevator cars and first and second shaft walls. Space in the shaft head or shaft pit, where the drives are usually arranged, can thereby be saved. 
     Advantageously the drive of the middle elevator car is positioned at the first shaft wall and the two drives of the adjacent elevator cars are positioned at the opposite, second shaft wall. 
     The advantage of the elevator installation resides in the flexible and simple positioning of however many drives and the associated elevator cars in the same shaft. In a conventional arrangement of the drives in the shaft head, thereagainst, the number of drives which can be installed is limited by the space available in the shaft head. Equally, a guidance of the tension elements free of conflict in such a conventional arrangement of the drives in the shaft head is subject to close limits. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which: 
         FIG. 1  is a schematic side elevation view of an arrangement of an elevator of an elevator installation with three elevator cars, three drives, three drive pulleys, three tension means and several deflecting rollers in accordance with the present invention; 
         FIG. 2  is a schematic plan view of the middle elevator of the elevator installation according to  FIG. 1 ; 
         FIG. 3  is a schematic plan view of an optional arrangement of the middle elevator of the elevator installation according to  FIG. 1 ; 
         FIG. 4  is a perspective view of an arrangement of the drives on cross members of the elevator installation according to the present invention; 
         FIG. 5  is a schematic side elevation view of an elevator installation according to the present invention in a building with two building zones; and 
         FIG. 6  is a schematic side elevation view of an elevator installation according to the present invention in a building with four building zones. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The U.S. provisional patent application Ser. No. 60/871,879 filed Dec. 26, 2006 is hereby incorporated herein by reference. 
     The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner. In respect of the methods disclosed, the steps presented are exemplary in nature, and thus, the order of the steps is not necessary or critical. 
     The elevator shaft is a space which is defined by six boundary planes and in which one or more elevator cars can be moved along a travel path. Usually four shaft walls, a ceiling and floor form these six boundary planes. However, it is equally conceivable that an upper or lower travel path limitation represents a boundary plane. This definition of the shaft can be expanded in the sense that several travel paths, along each of which one or more elevator cars are movable, are also arranged in a shaft horizontally adjacent to one another. 
       FIG. 1  shows an elevator with at least three elevator cars  7   a ,  7   b ,  7   c  which each have an associated drive A 1 , A 2 , A 3  and are movable independently of one another in a vertical direction. In that case a middle elevator car  7   a  is arranged between two adjacent elevator cars  7   b ,  7   c , which are disposed respectively below and above the middle elevator car  7   a.    
     The associated drives A 1 , A 2 , A 3  are positioned laterally at first and second shaft walls. The first and second shaft walls are those mutually opposite shaft walls not having shaft doors. The drive A 1  of the middle elevator car  7   a  is positioned at the first shaft wall and the two drives A 2 , A 3  of the adjacent elevator cars  7   b ,  7   c  are positioned at the opposite second shaft wall. In that case the drives A 1 , A 2 , A 3  are positioned in alternation on opposite shaft walls. Additional drives (not shown) of further elevator cars are alternately arranged at first and second shaft walls in correspondence with the alternating ordering of the drives. 
     The drives A 1 , A 2 , A 3  are positioned in  FIG. 1  at three different shaft heights, wherein the drives A 2 , A 3  of the adjacent elevator cars  7   b ,  7   c  are positioned above or below the drive A 1  of the middle elevator car  7   a . As a rule the distance in vertical direction between the middle drive A 1  and the adjacent drive A 2 , A 3  is at least one car height. 
     It is, however, also possible to position two drives at the same shaft height. For example, the drive A 1  of the middle elevator car  7   a  can be arranged on a first shaft wall and the drive A 3  of the adjacent, upper elevator car  7   c  on the opposite, second shaft wall at the same shaft height. The advantage of this arrangement resides in the simple maintenance of the two drives A 1 , A 3 . These can, in particular, be maintained from a common platform. 
     The drive A 1 , A 2 , A 3  has a respective motor M 1 , M 2 , M 3  and a respective drive pulley  1   a ,  1   b ,  1   c . The motor M 1 , M 2 , M 3  is disposed in operative contact with the drive pulley  1   a ,  1   b ,  1   c  and drives an associated tension means Z 1 , Z 2 , Z 3  by means of this drive pulley  1   a ,  1   b ,  1   c . The drive pulley  1   a ,  1   b ,  1   c  is so designed that it is suitable for receiving one or more tension means Z 1 , Z 2 , Z 3 . The tension means Z 1 , Z 2 , Z 3  are preferably belts, such as wedge-ribbed belts with ribs at one side which engage in one or more depressions at the drive pulley side. Belt variants such as smooth belts and belts toothed on one side or both sides with corresponding drive pulleys  1   a ,  1   b ,  1   c  are equally usable. In addition, different kinds of cables such as single cables, double cables or multiple cables are also usable. The tension means Z 1 , Z 2 , Z 3  comprise strands of steel wire or aramide or Vectran (a registered trademark of CNA Holdings, Inc. of Summit, N.J.) material. 
     The at least three elevator cars  7   a ,  7   b ,  7   c  and three counterweights  12   a ,  12   b ,  12   c  are suspended at the tension means Z 1 , Z 2 , Z 3  in a block-and-tackle manner. In that case the elevator cars  7   a ,  7   b ,  7   c  have at least one first and at least one second deflecting roller  2   a ,  2   b ,  2   c ,  3   a ,  3   b ,  3   c  which are fastened in the lower region of the elevator cars  7   a ,  7   b ,  7   c . These deflecting rollers  2   a ,  2   b ,  2   c ,  3   a ,  3   b ,  3   c  have, at the outer circumference, one or more grooves which are such that they can receive one or more of the tension means Z 1 , Z 2 , Z 3 . The deflecting rollers  2   a ,  2   b ,  2   c ,  3   a ,  3   b ,  3   c  are thus suitable for the guidance of the tension means Z 1 , Z 2 , Z 3  and are brought into contact with the latter. An elevator car  7   a ,  7   b ,  7   c  is thus preferably suspended as a lower block-and-tackle. 
     In an optional form of embodiment the deflecting rollers  2   a ,  2   b ,  2   c ,  3   a ,  3   b ,  3   c  are disposed in the upper region of the elevator car  7   a ,  7   b ,  7   c . In correspondence with the above description, the elevator car  7   a ,  7   b ,  7   c  is then suspended as an upper block-and-tackle. 
     Disposed in the upper region of the counterweights  12   a ,  12   b ,  12   c  is a third deflecting roller  4   a ,  4   b ,  4   c , which is similarly suitable, analogously to the deflecting rollers  2   a ,  2   b ,  2   c ,  3   a ,  3   b ,  3   c , to receive one or more of the tension means Z 1 , Z 2 , Z 3 . Correspondingly, the counterweight  12   a ,  12   b ,  12   c  is preferably suspended at the third deflecting roller  4   a ,  4   b ,  4   c  as an upper block-and-tackle below the associated drive A 1 , A 2 , A 3 . 
     The tension means Z 1 , Z 2 , Z 3  is led from a first fixing point  5   a ,  5   b ,  5   c  to a second fixing point  6   a ,  6   b ,  6   c  via the first, second and third deflecting rollers  2   a ,  2   b ,  2   c ,  3   a ,  3   b ,  3   c ,  4   a ,  4   b ,  4   c  and the drive pulley  1   a ,  1   b ,  1   c  from a first shaft wall to the second shaft wall. The first fixing point  5   a ,  5   b ,  5   c  is in that case disposed opposite the associated drive A 1 , A 2 , A 3  at approximately the same shaft height in the vicinity of a first or second shaft wall. The second fixing point  6   a ,  6   b ,  6   c  is disposed in the vicinity of the associated drive A 1 , A 2 , A 3  on an opposite second or first shaft wall. 
     The tension means Z 1 , Z 2 , Z 3  runs from the first fixing point  5   a ,  5   b ,  5   c  along a first or second shaft wall downwardly to the second deflecting roller  3   a ,  3   b ,  3   c , loops around this from the outside to the inside at an angle of approximately 90° and leads to the first deflecting roller  2   a ,  2   b ,  2   c . The tension means Z 1 , Z 2 , Z 3  loops around this first deflecting roller  2   a ,  2   b ,  2   c  from the inside to the outside again through approximately 90° and is thereafter led along the elevator car  7   a ,  7   b ,  7   c  upwardly to the drive pulley  1   a ,  1   b ,  1   c  and loops around this from the inside to the outside through approximately 150°. Depending on the setting of the optional setting pulley  13   a ,  13   b ,  13   c  the looping angle can be set in a range of 90 to 180°. The tension means Z 1 , Z 2 , Z 3  is thereafter led along a second or first shaft wall downwardly to the third deflecting pulley  4   a ,  4   b ,  4   c , loops around this from the outside to the inside through approximately 180° and is again led along a second or first shaft wall upwardly to the second fixing point  6   a ,  6   b ,  6   c.    
     As mentioned above, the setting pulley  13   a ,  13   b ,  13   c  is an optional component of the drive A 1 , A 2 , A 3 . With this setting pulley  13   a ,  13   b ,  13   c  the looping angle of the tension means Z 1 , Z 2 , Z 3  at the drive pulley  1   a ,  1   b ,  1   c  can be set, or increased or reduced, in order to transmit the desired traction forces from the drive pulley  1   a ,  1   b ,  1   c  to the tension means A 1 , A 2 , A 3 . Depending on the respective spacing of the setting pulley  13   a ,  13   b ,  13   c  from the drive pulley  1   a ,  1   b ,  1   c  the spacing of the tension means Z 1 , Z 2 , Z 3  from the drive A 1 , A 2 , A 3 , from the counterweight  12   a ,  12   b ,  12   c  or from the elevator car  7   a ,  7   b ,  7   c  can additionally be set. A conflict-free guidance of the tension means Z 1 , Z 2 , Z 3  in the shaft between the drive pulley  1   a ,  1   b ,  1   c  and the first deflecting roller  2   a ,  2   b ,  2   c  is thus guaranteed. 
     The elevator car  7   a ,  7   b ,  7   c  as well as the respectively associated drives A 1 , A 2 , A 3 , drive pulleys  1   a ,  1   b ,  1   c , deflecting rollers  2   a ,  2   b ,  2   c ,  3   a ,  3   b ,  3   c ,  4   a ,  4   b ,  4   c , optional setting pulleys  13   a ,  13   b ,  13   c , counterweights  12   a ,  12   b ,  12   c , tension means Z 1 , Z 2 , Z 3  and fixing points  5   a ,  5   b ,  5   c ,  6   a ,  6   b ,  6   c  form an elevator unit. Consequently,  FIG. 1  shows an elevator which has three elevator units, which in turn forms a triple group  14 . 
     Proceeding from the middle elevator unit with the elevator car  7   a , the adjacent lower elevator unit with the elevator car  7   b  and an adjacent upper elevator unit with elevator car  7   c  are respectively arranged in mirror image with respect to the middle one. The drives A 1 , A 2 , A 3  of the elevator units thus lie on mutually opposite first or second shaft walls and the associated drive pulleys  1   a ,  1   b ,  1   c , deflecting rollers  2   a ,  2   b ,  2   c ,  3   a ,  3   b ,  3   c ,  4   a ,  4   b ,  4   c , setting pulleys  13   a ,  13   b ,  13   c , counterweights  12   a ,  12   b ,  12   c , tension means Z 1 , Z 2 , Z 3  and fixing points  5   a ,  5   b ,  5   c ,  6   a ,  6   b ,  6   c  of adjacent elevator cars  7   a ,  7   b ,  7   c  are also arranged in mirror image. This rule of mirror-image arrangement of middle and adjacent elevator units applies to any desired number of elevator units installed in a shaft. 
     A further characteristic of the arrangement of the elevator units is that the associated drives A 1 , A 2 , A 3  and first fixing points  5   a ,  5   b ,  5   c  are positioned at approximately the same height at opposite first and second shaft walls. The shaft height predetermined by the fixing points  5   a ,  5   b ,  5   c  and the drives A 1 , A 2 , A 3  is also at the same time the highest point which an associated elevator car  7   a ,  7   b ,  7   c  can reach, since the tension means in the illustrated form of embodiment cannot raise a suspension point of an elevator car  7   a ,  7   b ,  7   c  above the height of the associated drive pulley  1   a ,  1   b ,  1   c . The positioning of the drives A 1 , A 2 , A 3  and the first fixing points  5   a ,  5   b ,  5   c  of the middle and adjacent elevator cars  7   a ,  7   b ,  7   c  is usually carried out at different shaft heights. The elevator cars  7   a ,  7   b ,  7   c  can thus reach only different maximum shaft heights. Correspondingly, the middle and the adjacent elevator cars  7   a ,  7   b ,  7   c  are allocated to different car zones in which the elevator cars  7   a ,  7   b ,  7   c  are movable. 
     The car zones K 1 , K 2 , K 3  allocated to the elevator cars  7   a ,  7   b ,  7   c  are evident in  FIG. 1 . It is apparent therefrom that the shaft height of a drive A 1 , A 2 , A 3  in the afore-described configuration predetermines the maximum shaft height of such a car zone K 1 , K 2 , K 3 . The minimum shaft height of a car zone K 1 , K 2 , K 3 , thereagainst, is defined by the drive A 1 , A 2 , A 3  of the next-but-one elevator unit disposed thereunder. In the illustrated example of embodiment the counterweight  12   c  of the adjacent upper elevator car  7   c  and the drive A 2  of the next-but-one adjacent lower elevator car  7   b  disposed thereunder is disposed, due to the mirror-image construction of middle and adjacent elevator units, on the same first or second shaft wall. The lowest shaft height reachable by the counterweight  12   c  is thus limited by the drive A 2  disposed thereunder on the same shaft wall. The travel range of the counterweight  12   c  between drive A 2  and the drive A 3  thus defines, for simultaneous 2:1 suspension of the associated elevator car  7   c  and the counterweight  12   c , the car zone K 3  of the elevator car  7   c.    
     If use is made of this teaching for the triple group  14 , partly overlapping car zones K 1 , K 2 , K 3  result, wherein only middle and adjacent car zones K 1 , K 2 , K 3  overlap. In a high-rise building with several triple groups  14  arranged one above the other all floors disposed in a middle car zone K 1  are thus served by two elevator cars. 
     According to  FIG. 2  the elevator cars  7   a ,  7   b ,  7   c  are guided by two car guide rails  10 . 1 ,  10 . 2 . The two car guide rails  10 . 1 ,  10 . 2  form a connecting plane V which extends in each instance approximately through the center of gravity S of the elevator cars  7   a ,  7   b ,  7   c . In the illustrated form of embodiment the elevator cars  7   a ,  7   b ,  7   c  are suspended eccentrically. Here only the arrangement of two elevator units arranged directly one above the other is shown. However, it is clear to the expert that the arrangement for further pairs of elevator units arranged directly one above the other takes place analogously thereto. 
     The tension means Z 1 , Z 2 , Z 3  and the associated guide means, such as deflecting rollers  2   a ,  2   b ,  2   c ,  3   a ,  3   b ,  3   c ,  4   a ,  4   b ,  4   c  and drive pulleys  1   a ,  1   b ,  1   c , in this suspension arrangement lie on one side of the connecting plane V, wherein the deflecting rollers  4   a ,  4   b ,  4   c  are, for the sake of clarity, not illustrated in  FIG. 2 , i.e. all afore-mentioned components associated with the elevator car  7   a ,  7   b ,  7   c  lie either between third shaft walls and the connecting plane V or between fourth shaft walls and the connecting plane V. Third or fourth shaft walls denote shaft walls which have at least one shaft door  9  and opposite shaft walls. The spacing y of the tension means Z 1 , Z 2 , Z 3  and the connecting plane V is advantageously approximately the same. The tension means Z 1 , Z 2 , Z 3  of the elevator car  7   a ,  7   b ,  7   c  lie alternately on one or the other side of the connecting plane V. Thus, the moments produced by the eccentric suspension of the elevator cars  7   a ,  7   b ,  7   c  have opposite effect. In the case of the same rated load of the elevator cars  7   a ,  7   b ,  7   c  and in the case of an even number of the elevator cars  7   a ,  7   b ,  7   c  the moments acting on the guide rails  10 . 1 ,  10 . 2  significantly rise. 
     The counterweights  12   a ,  12   b ,  12   c  are guided by two counterweight guide rails  11   a . 1 ,  11   a . 2 ,  11   b . 1 ,  11   b . 2 . The counterweights  12   a ,  12   b ,  12   c  are positioned at opposite shaft walls between the car guide rails  10 . 1 ,  10 . 2  and the first or second shaft walls. Advantageously, the counterweights  12   a ,  12   b ,  12   c  are suspended at their center of gravity at the tension means Z 1 , Z 2 , Z 3 . Since the elevator cars  7   a ,  7   b ,  7   c  are eccentrically suspended, the counterweights  12   a ,  12   b ,  12   c  are laterally offset in the vicinity of the third and fourth shaft walls. 
     The axes of rotation of the drive pulleys  1   a ,  1   b ,  1   c  and of the deflecting rollers  2   a ,  2   b ,  2   c ,  3   a ,  3   b ,  3   c ,  4   a ,  4   b ,  4   c  lie parallel to the first or second shaft walls. In the illustrated embodiment the afore-mentioned components are of the form that they can accept four parallelly extending tension means Z 1 , Z 2 , Z 3 , guide these or, in the case of the drive pulley  1   a ,  1   b ,  1   c , also drive these. In order to be able to receive the tension means Z 1 , Z 2 , Z 3  the deflecting rollers  2   a ,  2   b ,  2   c ,  3   a ,  3   b ,  3   c ,  4   a ,  4   b ,  4   c  and drive pulleys  1   a ,  1   b ,  1   c  have four specially constructed contact surfaces, which in the case of cables are designed, for example, as grooves or in the case of belts, for example, also as dished surfaces or toothing or, in the case of a contact surface of flat construction, are provided with guide shoulders. These four contact surfaces can be formed either on a common roller-shaped base body or respectively on four individual rollers with a common axis of rotation. 
     With knowledge of this form of embodiment numerous possibilities of variation according to the respective objective are available to the expert. Thus, this can arrange one to four or more individual rollers with or without a spacing relative to one another on one axis of rotation. In that case each roller can accept, depending on the respective design, one to four or, in the case of need, even more tension means Z 1 , Z 2 , Z 3 . 
     In normal operation of the elevator, the elevator cars  7   a ,  7   b ,  7   c  are placed at a floor stop flush with the floor and the car doors  8  are opened together with the shaft doors  9  so as to enable transfer of passengers from the floor to the elevator cars  7   a ,  7   b ,  7   c  and conversely. 
       FIG. 3  shows an alternative suspension arrangement with centrally suspended elevator cars  7   a ,  7   b ,  7   c . Here only the arrangement of two elevator units arranged directly one above the other is shown. However, it will be clear to the expert that the arrangement for further pairs of elevator units arranged directly one above the other takes place analogously thereto. 
     In that case the tension means Z 1 , Z 2 , Z 3  are led from the deflecting rollers and drive pulleys  1   a ,  1   b ,  1   c  on both sides of the connecting plane V. Advantageously, the suspension is then arranged symmetrically with respect to the connecting plane V. Since in this case the suspension center of gravity substantially coincides with the center of gravity S of the elevator cars  7   a ,  7   b ,  7   c  no additional moments act on the car guide rails  10 . 1 ,  10 . 2 . 
     In this central suspension of the elevator cars  7   a ,  7   b ,  7   c  the associated deflecting rollers  2   a . 1 ,  2   a . 2 ,  2   b . 1 ,  2   b . 2 ,  3   a . 1 ,  3   a . 2 ,  3   b . 1 ,  3   b . 2  and drive pulleys  1   a . 1 ,  1   a . 2 ,  1   b . 1 ,  1   b . 2  consist of at least two rollers arranged on the left and right of the connecting plane V. The deflecting rollers  4   a ,  4   b ,  4   c  of the counterweights  12   a ,  12   b ,  12   c  similarly consist of two rollers arranged on the left and the right of the connecting plane V, but for the sake of clarity are not illustrated in  FIG. 3 . In the present example the deflecting rollers  2   a . 1 ,  2   a . 2 ,  3   a . 1 ,  3   a . 2  and the drive pulleys  1   a . 1 ,  1   a . 2 , which are associated with the middle elevator car  7   a , lie at a first spacing x from the connecting plane V and the deflecting rollers  2   b . 1 ,  2   b . 2 ,  3   b . 1 ,  3   b . 2  and the drive pulley  1   b , which are associated with the adjacent lower elevator car  7   b , at a second spacing X from the connecting plane V, wherein the first spacing x is smaller than the second spacing X. A conflict-free guidance of the tension means Z 1 , Z 2 , Z 3  in the case of central suspension of the elevator cars  7   a ,  7   b ,  7   c  is thereby guaranteed. 
     Here, too, the counterweights  12   a ,  12   b ,  12   c  are advantageously suspended at their center of gravity S at the tension means Z 1 , Z 2 , Z 3  between the car guide rails  10 . 1 ,  10 . 2  and first or second shaft walls. Since the elevator cars  7   a ,  7   b ,  7   c  are now centrally suspended, the counterweights  12   a ,  12   b ,  12   c  also lie in a central region of the first and second shaft walls. Thanks to this central position of the counterweights  12   a ,  12   b ,  12   c  the free space between the lateral ends of the counterweights  12   a ,  12   b ,  12   c  and the third and fourth shaft walls increases. Design freedom for the counterweights  12   a ,  12   b ,  12   c  is thereby gained. Thus, for example, a narrower and wider counterweight  12   a ,  12   b ,  12   c  can be used in order to better utilize the space. For a given shaft cross-section, the elevator car  7   a ,  7   b ,  7   c  gains width or, for a given car size, the shaft cross-section can be reduced. 
     The centric and eccentric suspension variants, which are shown in  FIGS. 2 and 3 , can be combined as desired with the following examples of  FIGS. 5 and 6 . 
     As shown in  FIG. 4 , the drive A 1  has the motor M 1 , preferably an electric motor, the drive pulley  1   a  and optionally the setting pulley  13   a  by which the looping angle of the tension means Z 1  about the drive pulley  1   a  and the horizontal spacing of the tension means Z 1  from the drive A 1  to the elevator car  7   a  or the counterweight  12   a  can be set. 
     The motor M 1  lies vertically above the drive pulley  1   a . Thanks to this arrangement the drive can be positioned in the clear projection of the counterweights  12   a  between the elevator cars  7   a  and the first and second shaft walls. The drive A 1  can thereby be moved past by the elevator car  7   a  and can thus be mounted in an otherwise unneeded space of the shaft. By comparison with conventional elevators without an engine room there is thereby obtained space in the shaft head and/or in the shaft pit. 
     According to  FIG. 4  the drive A 1  is fixed on a cross member  19 , which is fastened to the car guide rail  10 . 1  and/or to the counterweight guide rails  11   a . 1 ,  11   a . 2 . There can be further seen in  FIG. 4  the third deflecting roller  4   a , at which the counterweight  12   a  is suspended, and in the background the elevator car  7   a . The example shown here is in mirror image with respect to the connecting plane V by comparison with the arrangement of  FIG. 2 . 
     The drives A 1 , A 2 , A 3  can also be optionally fixed directly on the shaft walls and in that case the cross members  19  are saved. 
       FIG. 5  shows an elevator installation for a building with zonal division. A building zone G 1 , G 2  is composed of several floors of the building disposed vertically one above the other. In that case at least one of these floors of the building zones G 1 , G 2  is a so-termed transfer floor. It is usual to go from one building zone G 1  to another building zone G 2  by means of a feeder elevator which stops only at the transfer floors. Here this feeder elevator is designed as a high-speed elevator. The number of remaining floors allocated to a building zone G 1 , G 2  is defined by those floors which are served by a take-away elevator  14 . 1 ,  14 . 2 . This take-away elevator  14 . 1 ,  14 . 2  undertakes fine distribution of the passengers from the transfer floors to the destination floors thereof. 
     The building is here divided into the two building zones G 1 , G 2 . Allocated to each of these building zones G 1 , G 2  is a triple group  14 . 1 ,  14 . 2  which exclusively serves floors of the allocated building zone G 1 , G 2 . The elevator installation has three elevators which are arranged in two shafts  15 . 1 ,  15 . 2 . Disposed in the first shaft  15 . 1  are two triple groups  14 . 1 ,  14 . 2 , which are arranged one above the other, with six elevator units, six elevator cars and the associated car zones K 1 . 1 , K 1 . 2 , K 1 . 3 , K 2 . 1 , K 2 . 2 , K 2 . 3 . A change from the first building zone G 1  to the second building zone G 2  thus necessarily takes place by way of the elevator of the second shaft  15 . 2  and only from the transfer floors U 1 . 1 , U 1 . 2  of the building zone G 1  to the transfer floors U 2 . 1 , U 2 . 2  of the building zone G 2 . The two triple groups  14 . 1 ,  14 . 2  are responsible for the transport of the passengers from the transfer floors U 2 . 1 , U 2 . 2  to a floor of the corresponding building zone G 1 , G 2  and between any two floors within a building zone G 1 , G 2 . A more efficient channeled transport of passengers within the building is thus achieved. 
     The first shaft  15 . 1  can be optionally subdivided into two separate individual shafts each with a respective elevator. The shaft height of these individual shafts is substantially oriented to the height of the corresponding building zone G 1 , G 2 . The advantage of such separated individual shafts is the elimination of chimney effect and in turn also the elimination of undesired strong shaft drafts, such as can occur in high shafts. 
     A high-speed elevator which exclusively serves the transfer floors U 1 . 2 , U 1 . 1 , U 2 . 1 , U 2 . 2  is moved in the second elevator shaft  15 . 2 . This high-speed elevator is, in the illustrated example, a double-decker elevator with two fixedly connected cars which are arranged vertically one above the other and are movable in common in the shaft  15 . 2 . These double-decker cars serve two transfer floors U 1 . 2 , U 1 . 1 , U 2 . 1 , U 2 . 2  arranged directly one above the other. 
     Each car zone K 1 . 1 , K 1 . 2 , K 1 . 3 , K 2 . 1 , K 2 . 2 , K 2 . 3  in each building zone G 1 , G 2  has at least one transfer floor U 1 . 2 , U 1 . 1 , U 2 . 1 , U 2 . 2 . The following arrangement, by way of example, results in the upper building zone G 2 : the transfer floors U 2 . 1 , U 2 . 2  of the double-decker elevator lie in a central region of the building zone G 2 , the lower transfer floor U 2 . 2  is served by the lower car of the double-decker car and the middle and lower adjacent elevator car of the triple group  14 . 1  and the upper transfer floor U 2 . 1  is served correspondingly by the upper car of the double-decker car and the middle and upper adjacent elevator car of the triple group  14 . 2 . Thus, passengers whose destination floor lies in the middle car zone K 1 . 2  always have available two elevator cars of the triple group  14 . 2  for onward travel. 
     Whereas the adjacent car zones K 2 . 2 , K 3 . 2  preferably each comprise a respective half of the floors of a building zone, the middle car zone K 1 . 2  preferably has two floors less than the number of floors allocated to the building zone G 2 . Accordingly, the middle elevator car can serve all middle floors of the building zone G 2  apart from the two boundary floors. The middle elevator car can, due to the vertical stacking of the elevator cars of the triple group  14 . 2 , not travel past the upper or lower adjacent cars which each keep occupied at least one boundary floor of the building zone G 2 . 
     In the case of a minimum size of the middle car zone K 1 . 2  this comprises the two transfer floors U 2 . 1 , U 2 . 2 . In this instance the middle elevator car of the triple group  14 . 2  takes over for the building zone G 2  the function of an escalator  16 , in that it transports the passengers from the upper transfer floor U 2 . 1  to the lower transfer floor U 2 . 2  and conversely. The two transfer floors U 2 . 1 , U 2 . 2  are then also the sole floors of the building zone G 2  which are each served by two elevator cars of the triple group  14 . 2 . 
     In the maximum extent of the middle car zone K 1 . 2 , thereagainst, the two boundary floors of the building zone G 2  remain the sole floors which are served only by the adjacent lower or upper elevator car of the triple group  14 . 2 . All other floors are served, in the maximum extent of the middle car zone K 1 . 2 , by two elevator cars. 
     The arrangement of the car zones K 1 . 1 , K 2 . 1 , K 3 . 1 , the associated elevator units and the transfer floors U 1 . 1 , U 1 . 2  in the building zone G 1  substantially corresponds with the arrangement of the said elements of the building zone G 2 . A more important additional aspect relates to the transfer floors U 1 . 1 , U 1 . 2  of the lower building zone G 1 . 
     The two transfer floors U 1 . 1 , U 1 . 2  of the lower building zone G 1  are connected by an escalator  16 . The escalators are often used in building lobbies. The building lobbies are floors in which the passengers enter the building and also leave again and are accordingly frequented by numerous passengers. If, for example, the lower transfer floor U 1 . 2  is now a building lobby, the inflowing passengers now pass, in the case of need, rapidly to the upper transfer floor U 1 . 1  thanks to the high conveying performance of the roller escalator  16  or pass, when leaving the building, rapidly from this back to the building lobby. Depending on the respective kind and position of the building the building lobby can in principle lie on any floor of the building. The building lobby is in that case usually served by at least one high-speed elevator of the second shaft  15 . 2 . 
       FIG. 6  shows a building with two additional building zones G 3 , G 4  and associated triple groups  14 . 3 ,  14 . 4  together with the car zones K 1 . 3 , K 2 . 3 , K 3 . 3 , K 1 . 4 , K 2 . 4 , K 3 . 4  as well as the associated transfer floors U 3 . 1 , U 3 . 2 , U 4 . 1 , U 4 . 2 . As many triple groups  14  as desired can thus be arranged vertically one above the other. 
     The invention is not restricted only to the illustrated forms of embodiment. With knowledge of the invention it is obvious to the expert to optimize different parameters for specific forms of building. Instead of a double-decker car it is also possible for several or individual single cars or multi-cars, which have more than two cars connected together, to be moved in the second shaft  15 . 2 . In addition, the number of floors allocated to a building zone “G” is freely selectable. The building zones “G” also do not need to have the same number of floors, but the number can vary from building zone to building zone. It is also not always necessary for only triple groups  14  to be assigned to a building zone “G”. Thus, quadruple, quintuple or sextuple groups, etc., can also be assigned to the building zones “G”. The car zones do not have to be symmetrically constructed, for example, within a triple group. Depending on the position of the drives and the transfer floors these car zones “K” are freely adaptable to the specific building conditions. Finally, the transfer floors “U” can also be freely arranged with respect to number and position in a building zone “G” in dependence on the car zones “K” or number of cars of a multi-car. 
     The following simple calculation shows that due to the present invention a significant increase in conveying performance can be achieved. For a building zone G 2  with, for example, ten floors, according to the state of the art two elevator cars each serve nine floors, i.e. each elevator car has per floor a transport coefficient of 1.9 weighted by the number of floors to be served, which coefficient represents a measure for the conveying performance of the elevator car in a specific floor. This gives for the two boundary floors, which are each served only by one elevator car, a transport coefficient each of 1/9 and, for a central region of eight floors where the two car zones overlap, a transport coefficient of 2/9. 
     According to the present invention the adjacent car zones K 2 . 2  and K 3 . 2  each serve five upper and five lower floors and the middle car zone K 1 . 2  serves eight floors. A transport coefficient of 1/5 plus 1/8, or 13/40, results therefrom for the region of overlapping car zones, and a transport coefficient of 1/5 for the boundary floors. 
     This simple computation example shows that a significantly increased conveying performance results for all floors of the building zone G 2 . The increase in conveying performance for the two boundary floors is even of over-proportional size. In addition, it can be readily seen that this increase in conveying performance also applies for a number, which is different from “10”, of floors in a building zone. 
     In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.