Abstract:
Vertical transport system in a building provided with one or more hoistways with elevator cars moving in them, comprises at least one hoistway accommodating at least two elevator cars travelling above one another in such a manner that one (2) of the cars travels in the hoistway (1) between the entrance floor and a certain higher floor or certain higher floors, i.e. change levels (11,13a,13b,18). One or more other cars (4,5) travel in the part of the same hoistway (1) which lies above the change levels (11,13a,13b,18), in the spaces between or divided by the hoisting ropes (3) of the elevator operating in the lower part of the hoistway.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a vertical transport system in a building having one or more hoistways and elevator cars travelling in them. 
     DESCRIPTION OF THE BACKGROUND ART 
     Previously known vertical transport systems in buildings are generally based on elevators whose cars travel essentially through the whole length of the vertical shafts provided for them. However, in sky scrapers, where the space required by the transport system is a cost factor which is the more critical the higher the building is, the space required by elevator system has not been effectively minimized. On the contrary, in very tall buildings, in order to maintain a high service standard of the transport systems, it has been necessary to resort to various arrangements for the division of work between elevator groups e.g. by providing the building with one or more so-called sky lobbies or change levels which serve as terminal floors for certain elevator groups and as starting floors for other groups, and where the passengers change elevators if they desire to travel further in either direction. These arrangements, including the machine rooms of the elevators operating below the sky lobby and the waiting rooms and escalators that may be needed for flexible transit traffic, occupy at least on certain floors even more space than before and cause delays in the traffic. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to achieve a new type of vertical transport system in which the spaces required by the hoistways in tall buildings are minimized and which maximizes the speed and flexibility of the transit traffic in the sky lobbies. 
     To achieve this object, the transport system of the invention is characterized in that it comprises at least one hoistway accommodating at least two elevator cars travelling above one another in such, a manner that one car travels in the hoistway between the entrance floor and a certain higher floor or certain higher floors, i.e. change levels, and that one or more other cars travel in the part of the same hoistway which lies above said change levels, in the spaces between or divided by the hoisting ropes of the elevator operating in the lower part of the hoistway. 
     The invention provides a variety of advantages, the most obvious of which are the reductions in the space requirements of the system. The change levels or sky lobbies can be made simpler and smaller because there will be less need for passengers to change between elevators travelling in different hoistways. The top and bottom spaces of the hoistways and their machine rooms, which in previously known systems had to be provided separately for each hoistway, are now combined. The invention reduces the need for stairs or similar arrangements, used especially at the terminals of elevator systems with double-decker cars to allow passenger traffic between hoistways. Also, since the hoistways of the elevators operating above those coming from below need not be built separately starting from the side of the hoistways of the latter, the space formed by the hoistways together in the building will become straighter and more symmetrical. The combined elevator hoistways thus form a supporting structure that extends from bottom to top of the sky-scraper and has a stronger structural design. Especially in buildings having a relatively narrow cross-sectional form, this advantage is more significant. 
     Another advantage, resulting from the simplification of the sky lobbies, is a reduction in the passengers&#39; total travelling time, because, when changing elevators, they need not walk long distances from one elevator to another to get to their destination. 
     Moreover, the system provides flexibility in the placement of the sky lobby. If required, minor changes of the placement of the lobby are relatively easy to carry out as it is no longer necessary to have any fixed building structures in conjunction with the lobby. 
     The other preferred embodiments of the invention are characterized by what is presented in the claims to follow. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described below in detail by the aid of examples, reference being made to the drawings attached which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
     FIG. 1 presents an embodiment of the transport system of the present invention; 
     FIG. 2 presents a simplified view of the system in FIG. 1 as seen from the right; 
     FIG. 3 presents an example of the change level used in the transport system illustrated by FIG. 1; 
     FIG. 4 presents an example of the change level used in another embodiment; and 
     FIG. 5 presents an example of the placement of the elevators in the hoistway in the transport system of the invention, seen from above. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates the transport system of the invention in a building where the main elevator operating between the entrance floor and the sky lobby uses a car with two decks 2a and 2b, i.e. a car of the &#34;double-decker&#34; type. As this type of car doubles the number of passengers that can be transported at a time, it is often used in tall buildings with the main elevators operating between two terminals only, the number of these elevators being usually 6-8. For the sake of clarity, the figure only shows one hoistway and the elevator cars operating in it. In reality there is more than one hoistway. Operating above the change level 11 or sky lobby there are two delivery elevators 4 and 5, which are substantially smaller than the main elevator. The cars of the delivery elevators travel on different sides of the hoisting ropes of the main elevator. The cars of both the main elevator and the delivery elevators travel in the same hoistway, operating in different parts of the hoistway except for the change levels. The hoisting ropes 3 and 6, 7 of all three elevators run through a common machine room 12 located above the delivery elevators. 
     The counterweights 9, 10 of the delivery elevators 4, 5 and the counterweight 8 of the main elevator travel on their guide rails in a space reserved for them. 
     To prevent collisions between the main elevator and the delivery elevators, the system always maintains a sufficient safety distance between the cars, which cannot be cancelled by the control algorithm of the elevator groups. In the determination of the safety distance, the length of the car cable (not shown) hanging below the delivery elevators is taken into account. 
     FIG. 2 presents a simplified view of the system of FIG. 1 as seen from the right. In this example, the compartments 2a, 2b of the main elevator car 2 are of the walk-through type, i.e. they have doors at both ends. The doors are so designed that the main elevator can use the same landing doors as the delivery elevators 4, 5. The orientation of the elevator cars relative to each other is shown in FIG. 2. Seen from the opposite side of the cars, the situation is fully analogous. 
     FIG. 3 illustrates a situation where the delivery elevators have arrived at the sky lobby. Since the main elevator has a double-decker car as shown in FIGS. 1 and 2, the sky lobby also comprises two floors on which the passengers may disembark from the main elevator The main elevator preferably has a walk-through car as mentioned above, in which case the delivery elevators will stop either at change level 13a or 13b depending on the calls, so that the stairs 16 and 17 shown in the figure are unnecessary. However, if this is not the case, i.e. if landing doors 14 and 15 are only provided on one side of the hoistway, a flexible change of elevators can be arranged e.g. by using stairs 16 and 17 together with indicators announcing the arrival of a delivery elevator. The change level may also consist of one floor only, in which case one of the compartments of a double-decker main car is first brought to the change level, whereupon, after the passengers have embarked and disembarked, the other compartment of the car is brought to the change level. However, in the case of double-decker elevators, a one-floor sky lobby is not as effective as a two-floor one with regard to passenger flow. 
     FIG. 4 illustrates a situation corresponding to FIG. 3 in a case where the main elevator has a single-deck walk-through car. Landing doors 14, 15 are provided on both sides of the hoistway and the delivery elevators 4,5 may be simultaneously at the sky lobby. This makes it easier to design the sky lobby and allows easy changes of its placement. 
     FIG. 5 shows a possible placement of the elevators in the hoistway 1 of the transport system of the invention as seen from above. The walk-through car 2 of the main elevator has two doorways A and B allowing passage to the landings. Each of the delivery elevators 4 and 5 has a car with one doorway. The doorway of elevator 4 faces the same side of the hoistway as doorway A of the main elevator while the doorway of elevator 5 faces the same side as main elevator doorway B. Thus, the same landing doors can be used at the sky lobby. The counterweights 8, 9 and 10 of the three elevators travel on their respective guide rails on one side of the hoistway. Since each elevator in the transport system only travels through part of the length of the hoistway, sufficient vertical space is left in the hoistway in addition to the range of motion of the counterweights to allow the height of the latter to be increased so as to make them sufficiently heavy. In this way, the counterweights are made narrow enough to permit them to be placed in the space between the holders of the guide rails of the three elevators. The figure does not show the holders to which the car and counterweight guide rails 19, 20 are attached. For the sake of clarity, the figure only shows a single hoisting rope 3, 6, 7 for each elevator. The machine room equipment, including the traction sheaves and diverting pulleys carrying the weight of the cars 3, 6, 7 and counterweights 8, 9, 10, are not shown. 
     The transport system of the invention can largely be controlled using existing modern control algorithms for elevator groups, e.g. the so-called meta control algorithm described in the applicant&#39;s Finnish patent application no. 863861, in which the control of the feeding elevator and the group control of the delivery elevators are coordinated. 
     The changes in the control and construction of an elevator system required for the implementation of the invention involve the supervision arrangements relating to the safety distance between elevator cars and program changes allowing the recognition of collision situations well in advance to prevent actual collisions. The end-of-hoistway supervision solutions employed in conventional elevators can be so applied that they will render collisions totally impossible. The buffers of the delivery elevators are placed at the change level. They can be mounted e.g. in the side walls of the hoistway in alignment with corresponding projections mounted on the elevator cars. 
     It is obvious to a person skilled in the art that different embodiments of the invention are not restricted to the examples described above, but that they may instead be varied within the scope of the following claims. For example, the lowest entrance into the transport system can be placed on a floor other than the bottom floor of the building and the transport of passengers to this floor arranged e.g. using escalators. Similarly, the main entrance into the building can be placed on a floor other than the bottom floor, in which case the main entrance into the transport system is usually placed on the same floor. 
     Also, the counterweights may be so placed in the hoistway that one or some of them travel directly above other counterweight(s). This is feasible especially in cases where the total length of the ranges of motion of the two delivery elevators is clearly less than the length of the hoistway. Another and quite usable possibility of achieving this is e.g. the use of diverting pulleys to change the suspension ratio so as to halve the range of motion of the counterweights, although in this case the weight of the counterweights must be increased correspondingly. 
     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.