Abstract:
The invention relates to an elevator system in tall buildings, the system having at least one first elevator shaft, which houses an elevator arranged to stop at floors called transfer levels, and at least one second elevator shaft, which houses elevators whose elevator cars are disposed one above the other in the elevator shaft, which elevator cars are designed to stop during their travel at any floor to which or from which a call has been issued. The second elevator shaft is divided vertically into local shafts situated one above the other, the number of which is at least one for each zone between transfer levels.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application is a Continuation of co-pending PCT International Application No. PCT/FI02/00816 filed on Oct. 21, 2002, which designated the United States, and on which priority is claimed under 35 U.S.C. § 120, the entire contents of which are hereby incorporated by reference. 

   BACKGROUND OF THE INVENTION 
   Field of the Invention 
   The present invention relates to an elevator system especially for high-rise multi-floor buildings where a passenger who wants to get to a floor in the top part has to change to an elevator that mainly serves the topmost floors only. 
   In very tall buildings, it is generally economically not possible to provide elevator shafts extending through the entire height of the building from the bottom floor to the top floor so that each elevator could serve all floors. For this reason, elevators are traditionally divided into different zones in the vertical direction, of which the lowest zone extends from the entrance floor, hereinafter called ground floor, to a floor at a given height, this zone being called low-rise zone, while the highest zone, called high-rise zone, extends from a given transfer floor, a so-called sky lobby floor to the topmost floors of the building. Between these zones, depending on the height of the building, there may be one or more intermediate zones, so-called mid-rise zones serving intermediate floors in the building from their respective transfer floors. The problem is generally that each zone is served by only one elevator in one elevator shaft, so it is necessary to provide for each zone and each elevator car a separate shaft extending from the ground floor of the building to the top floor of the zone. In addition, a machine room is generally provided above each elevator, which requires more space. Moreover, with increasing building height, there is the problem that it is difficult to provide a sufficient transport capacity especially to the higher floors, because in the highest shaft the traveling distance from the ground floor to the highest sky lobby is long. A further disadvantage is the highest shafts is the difficulty of compensation of long elevator ropes, which is not encountered in lower elevator shafts as the ropes are shorter. 
   In tall buildings, however, a single elevator aggregate with zone divisions like this does not have a sufficient capacity to serve all users; instead, several parallel elevators forming a group are needed in the same zone. A typical group consists of eight elevators serving the same zone, which may comprise e.g. floors  31 - 15 . Often an elevator group like this is needed for each zone, for example for a mid-zone to serve floors  16 - 30  and a top zone to serve floors  31 - 45 . The problem is that, in the case of this example,  24  elevator shafts are required, each of which extends from the ground floor upwards although only the eight elevators in the lowest group serve the fifteen lowest floors. The elevators serving the intermediate and top zones do not stop at the lower floors, so the lobby space and particularly the shaft space needed for them constitute expensive unused space for the owner of the building. The unused lobby spaces can be utilized e.g. as storage spaces or for lavatories on different floors, but the corresponding shaft space cannot be utilized in any way. 
   2. Description of Related Art 
   U.S. Pat. No. 5,419,414 represents a prior-art solution for an elevator arrangement in tall buildings. In this solution, three elevator cars are placed one over the other in the same shaft so that each car is moved separately by means of an elevator machine mounted above each common elevator shaft. Thus, a separate machine is provided for each elevator car, and the elevator ropes run from the machines to the elevator cars in a interlapping manner so that the ropes going to the lowest car pass by the two higher cars and the ropes going to the intermediate car pass by the uppermost car. The cars can be moved in relation to each other on at least four different operating principles. According to a first principle, each car always moves in its own shaft section and never enters the zone of another car. According to another principle, each car can serve all floors, but only one car can be moving at a time. According to a third principle, the cars can move simultaneously in different zones, but only in one direction at a time. Finally, according to a fourth operating principle, the cars can move simultaneously in different directions provided that safety is guaranteed. For example, when the two lower cars are going downwards, the highest car can move upwards. The proposed elevator system is very complicated and it is obvious that such a system involves the problem of how to construct a sufficiently simple and safe control system. Even if the control system were ever so safe, the system may still get out of order, in which case a collision between two cars is possible. 
   U.S. Pat. No. 6,273,217 also discloses an elevator solution in which more than one elevator cars are travel in the same elevator shaft. The solution presented in the patent is focused on preventing a possible collision of two elevator cars by means of a program. If a risk of collision appears, one of the elevator cars is moved away to give way to the other one. The problem in this case, too, is exactly a risk of collision, because there is always the possibility that, if a program malfunction or error occurs, two elevator cars running towards each other in the same shaft will collide. 
   BRIEF SUMMARY OF THE INVENTION 
   The object of the present invention is to eliminate the above-mentioned drawbacks and to achieve an economical, reliable and well-functioning elevator system for tall buildings, said elevator system comprising one or more elevator cars moving in the same shaft independently of each other. 
   The solution of the invention has the advantage that by using simple solutions a reliable and safe elevator system is achieved that guarantees a good transport capacity in tall buildings and enables space savings to be made in respect of expensive floor area. According to the invention, for an elevator system in a building of the same height, elevator shafts are only needed for two elevator groups instead of three and yet at least the same capacity is achieved as in prior-art solutions. The greatest space saving is gained by leaving out the above-mentioned lowest zone, the so-called low-rise zone as separate elevator shafts, so that the entire shaft and lobby spaces for this zone, i.e. e.g. floors  1 - 15 , can be used for other purposes. In the case of an elevator group of eight elevators, the additional area thus provided will be about 150 m 2  for each floor. As the fifteen lowest floors can well be used as business premises, the rent per square meter of area of such floor space is generally high and therefore the elevator system of the invention allows the owner of the building to earn a good income from rents. An additional advantage is that, although the elevator cars travel in the same shaft independently of each other, they never collide because the hoisting ropes of different elevator cars are not interlapped in the vertical direction and there is therefore no risk of the elevator cars getting into each other&#39;s range of movement. 
   The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
       FIG. 1  presents a simplified diagrammatic view of a prior-art elevator system as seen from the front side of the elevators, 
       FIG. 2  presents a simplified diagrammatic view of an elevator system according to the invention as seen from the front side of the elevators, 
       FIG. 3  presents a magnified view of a transfer level in the elevator system of the invention presented in  FIG. 2  as seen from the front side of the elevators, 
       FIG. 4  presents a simplified diagrammatic view of a transfer level as shown in  FIG. 3  as seen from above, 
       FIG. 5  presents an elevator shaft serving individual floors in an elevator system according to the invention, and the elevator cars in the shaft at a transfer level in lateral view and sectioned along line V—V in  FIG. 4 , and 
       FIG. 6  presents an elevator shaft serving the transfer levels in an elevator system according to the invention and a double-decker elevator car in the shaft at a transfer level, in lateral view and sectioned along line VI—VI in FIG.  4 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The solution illustrated in  FIG. 1  represents the aforesaid prior-art elevator system for tall buildings. Let us consider e.g. a 45-floor building with fifteen floors in each zone. The number of floors in each zone is determined by the number of elevators and the car size and speed of the elevators. The system comprises three different height zones, so it requires three different banks of elevator shafts  1 ,  2  and  3 , of which bank  1  forms the lowest zone, which comprises e.g. a group of eight elevators serving all fifteen lowest floors from the ground floor  9  to the highest floor  10  of the zone.  FIG. 1  only shows the elevator doors of four elevators on the ground floor  9  and the highest floor  10  of the zone. Within this zone, the elevators can stop at any floor. 
   The second zone in the prior-art elevator system is a so-called mid-zone, which may also comprise a group of eight elevators in a separate bank of elevator shafts  2 , which now serves only the ground floor  9 , the first transfer level  8 , which in the solution illustrated by the example is the fifteenth floor, and all floors above it up to the second transfer level  8   a , which in the solution illustrated by the example is the thirtieth floor of the building. The elevators in bank  2  never stop within the zone  5  of the lowest fifteen floors except at the ground floor. If these elevators in bank  2  do not have a so-called express function, then they will not take in any passengers from the ground floor  9  at all, but they only operate within zone  4  of bank  2 . In this case, no doors are provided on the ground floor  9  for the elevators in bank  2 . Thus, a person who wants to reach one of the floors in zone  4 , e.g. floor  20 , first has to take an elevator in bank  1  and have a ride on it to transfer floor  10 , then move on via a transfer area  8  to the elevator lobby lob for zone  4  and ride further on an elevator in zone  4  to floor  20 . 
   The high-rise zone of the prior-art elevator system is served by an elevator group in bank  3 . The elevators in this group do not stop at the floors  7  in the low-rise and mid-rise zones at all. Instead, they either operate exclusively between the floors of the high-rise zone  6 , e.g. floors  31 - 45 , or, if they are provided with an express function, they also travel from the ground floor  9  directly to the second transfer level  8   a , which is the lowest floor  11   b  of the high-rise zone. If no express function is implemented, then a passenger going to a floor in the upper zone  6  has to travel by the route: bank  1 , first transfer level  8 , zone  4  of bank  2 , zone  6  of bank  3 . For each zone,  FIG. 1  only shows the lowest floors  9 ,  10   b  and  11   b  and highest floors  10 ,  11  and  12 . The disadvantages of this system are as stated above. 
     FIGS. 2-6  present a system according to the invention. In this system, the separate elevator bank  1  for the lowest zone presented in  FIG. 1  as well as all the elevator lobbies on these floors have been left out. The system only comprises two banks of elevator shafts. In this example, the first bank  13  comprises eight elevator shafts, each shaft accommodating an elevator provided with a double-decker elevator car  21  and at least as fast as or faster than the elevators operating in bank  14 . The ground floor  9  is provided with an escalator arrangement  20  that passengers can use to ascend to and descend from the second ground floor level  9   a . In the lower part  15  of bank  13 , the elevator cars can only be entered from the ground floors  9  and  9   a  and from the elevator lobbies  10  and  10   a  on the first transfer level  8 . Likewise, in the upper part  16  of bank  13 , there is no entry into the elevator cars except from the elevator lobbies  10  and  10   a  at the first transfer level and from the elevator lobbies  11  and  11   a  at the second transfer level  8   a . In the case of the present example, the first elevator bank  13  extends from the ground floor to a height corresponding to about ⅔ of the entire height of the building, i.e. in a 45-floor building the second transfer level  8   a  at the top of the first bank comprises floors  30  and  31  of the building and similarly the first transfer level located midway up the first bank comprises floors  15  and  16  of the building. 
   The second elevator bank  14  extends substantially continuously from the ground floor  9  of the building through the entire height of the building, i.e. to the topmost floor  45 , which is represented by elevator lobby  12 . The second elevator bank  14  consists of three zones substantially similar to each other and situated one above the other. The shafts in these zones are hereinafter called local shafts  17 ,  18 ,  19 . All local shafts are substantially identical in cross-section and each local shaft accommodates one elevator car  22  operating in it, serving all floors within the local shaft. Thus, in the system of the example, each elevator shaft in bank  14  contains three elevators one above the other, each one in its own local shaft. In the present context, ‘elevator’ is to be understood as comprising at least an elevator car  22 , a drive machine  23  and hoisting ropes  24 . The elevators in the local shafts are slower than or at most as fast as the so-called shuttle elevators in bank  13 . 
   The first and the second elevator banks are interconnected via a two-floor transfer level. The first transfer level  8  is at a height of about one third of the total height of the building, so in the example it comprises floors fifteen and sixteen, provided with elevator lobbies  10  and  10   a . Similarly, the second transfer level  8   a  is at a height of about two thirds of the total height of the building, comprising in the example floors thirty and thirty-one with elevator lobbies  11  and  11   a . Each transfer level is provided with an escalator arrangement  20  for transporting passengers from the lower floor of the transfer level to the higher floor or vice versa. 
   As stated above, the first transfer level  8  and the second transfer level  8   a  each comprise a lower and an upper transfer floor so that each lower transfer floor, which also have elevator lobbies  10  and  11 , is the highest floor for the elevator car  22  operating in the local shaft  17  and  18 , which comes to that floor from below and leaves it in the downward direction. Similarly, each upper transfer floor, which also have elevator lobbies  10   a  and  11   a , is the lowest floor for the elevator car  22  operating in the local shaft  18  and  19 , which comes to that floor from above and leaves it in the upward direction. 
   Although the number of parallel shafts chosen for the example is eight, the structure of only one of the shafts in the second bank  14  will now be described. The other shafts are identical to the one described. In its basic structure, each shaft is continuous, extending at least from the ground floor  9  to the top floor of the building if necessary, which has an elevator lobby  12 . Each shaft comprises more than one local shaft  17 ,  18 ,  19  one above the other, and each local shaft accommodates one elevator with a car  22  serving all floors of the local shaft. The system described in the example thus comprises three local shafts  17 ,  18  and  19  one above the other, each of which contains one elevator car. All the elevator cars in the same shaft are substantially identical and installed in substantially the same vertical plane one above the other. 
     FIG. 5  presents a more detailed illustration showing how the elevator cars  22  are housed independently of each other one above the other in the same shaft. Here, the elevator car  22  of the middle local shaft  18  is in its lowest position at the upper floor of transfer level  8 , at elevator lobby  10   a . Below the elevator car, the local shaft  18  is provided with a number of supporting beams  25  forming a shaft bottom, which is additionally provided with a strong steel grid to stop any falling objects at this part of the shaft. The vertical direction from the supporting beams to the lowest position of the elevator car  22  has been fitted to be such that a free space of dimensions according to regulations is provided below the car. The local shaft is further provided with fixed buffers mounted on the supporting beams  25  or on a shaft wall in the lower part of the local shaft for stopping the elevator car  22  on buffer. The buffers are not shown in the figures. 
   Correspondingly, the lower local shaft  17  is provided with an elevator machine  23  for moving the lower elevator car, the machine being mounted below the supporting beams  25  at the upper end of the local shaft, the hoisting ropes  24  being passed around the traction sheave of the machine and fixed in a suitable manner to the elevator car  22 . In the figure, the lower elevator car  22  is shown in its highest position in local shaft  17  at transfer level  8 , standing at the lower floor of the transfer level, at elevator lobby  10 . The elevator machines  23  of all the elevators in the same shaft are mounted in a corresponding manner in the upper part of each local shaft  17  situated one above the other. In the solution illustrated by the example, each shaft also contains three elevator machines  23 , and no machine rooms are needed for the elevators in the local shafts  17 . Each local shaft is additionally provided with a counterweight  28 , which is partially shown in shaft  17 . When the elevator car  22  is in the upper part of the shaft, the counterweight is in its lower part and vice versa. 
   The elevator machine  23  is of gearless type and substantially flat, so it can be mounted e.g. on an elevator guide rail or on a shaft wall in the space between the wall of the elevator car  22  and the shaft wall. Thus, the elevator cars  22  can be easily implemented as units independent of each other because the hoisting ropes of different elevators are not interlapped in the vertical direction in any part of the shaft. 
     FIG. 6  presents a likewise simplified view of a double-decker elevator car  21  operating in the elevator shafts of the first bank  13 . In this case, an elevator machine is provided at the upper end of each shaft, with an elevator car  12  suspended on its ropes. The upper and lower cars of the elevator car are connected to each other via fixing elements  26  so that, when the upper car is at the upper floor of the first transfer level  8 , the lower car is at the lower floor of the same transfer level. The same also applies when the car is at the second transfer level  8   a  or at the ground floor  9 . 
   The ground floor and transfer level lobbies are provided with clear guide signs to inform passengers as to the level from which each floor can be reached. Now, supposing a passenger wants to go to floor twenty, he will see at the ground floor a guide sign indicating that the floor in question can be reached by taking any elevator starting from the ground floor  9 . The passenger then boards the lower car of a double-decker elevator car  21  in bank  13  from the ground floor  9  and ascends to the second transfer level  8   a , where he exits from the elevator at lobby  11  and walks along the transfer floor to an elevator car  22  in bank  14 , which takes him downward from floor thirty to floor twenty. If the passenger is going to floor fifty, he will first go by escalator to the upper level  9   a  and then board the upper car of a double-decker elevator car  21  to reach transfer level  8   a , where he goes further via elevator lobby  11   a  to an up-going elevator in bank  14 , which takes him to the desired floor. 
   It is obvious to the skilled person that the invention is not limited to the example presented above, but that it may be varied within the scope of the claims presented below. Thus, for example, the elevator machines may be only partially located in the elevator shafts, e.g. so that substantially only the traction sheave is in the elevator shaft while the rest of the elevator machine is in a suitable recess or equivalent set back from the shaft. An essential point is that each elevator car in the shaft has its own machine near the upper or lower end of the shaft section in which the car travels. Further, the number of vertical zones is not necessarily three but may vary according to building height, required transport capacity and selected elevator properties. These properties include e.g. the speed and size of the elevator car. The heights of the shafts needed are preferably so chosen that a double-decker elevator car  21  arriving at the highest transfer level can disembark passengers for both upward and downward transfer traffic. 
   Thus, the relation of the number of transfer levels and local shafts may vary in buildings of different heights. In addition, buildings of a height greater than in the example described above may have more transfer levels than two as in the example. Likewise, the height of the shafts may vary according to the shape of and space available in the building. 
   The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.