Abstract:
An elevator system includes an elevator car support displaceable in a travel area provided for the travel of the elevator car support, and a first elevator car and a second elevator car, each car adjustably disposed on the elevator car support. A drive unit is further disposed on the elevator car support. A belt is also provided. The first elevator car and the second elevator car are thereby adjustable in opposite directions by the drive unit by the belt relative to the elevator car support.

Description:
FIELD 
       [0001]    The invention relates to an elevator system having at least one elevator car support that can hold two or more elevator cars. The invention relates specifically to the field of elevator systems designed as so-called double-decker elevator systems. 
       BACKGROUND 
       [0002]    JP 2007-331871 A discloses a double-decker elevator. The known elevator has a car frame in which two elevator cars are arranged one vertically above the other. The two elevator cars each stand on a support with sheaves, lifting cables being guided around the sheaves. A drive unit, around which the lifting cable is guided, is moreover provided on the car frame. By actuating the lifting cable by means of the drive unit, the elevator cars suspended in this way can be raised and lowered relative to the car frame. As a result, the two elevator cars can be positioned differently inside the car frame. 
         [0003]    The double-decker elevator known from JP 2007-331871 A has the disadvantage that the mechanism provided for suspending and adjusting the elevator cars requires a relatively large amount of space. For example, the sheaves of the top elevator car, on which the top elevator car is suspended, require a certain structural space that, in the case of a predetermined structural space for the car frame, restricts the remaining space for the elevator car both vertically and horizontally. This also applies to the bottom elevator car. Specifically with respect to the architecturally predetermined shaft dimensions, this thus results in a reduced cross-section remaining for the elevator cars, which entails smaller elevator cars. Moreover, the space required vertically is also increased, which imposes additional demands on the design of the elevator shaft in terms of its end regions. 
       SUMMARY 
       [0004]    An object of the invention is to provide an elevator system which has an improved structure. Specifically, an object of the invention is to provide an elevator system in which the space remaining for the elevator cars is optimized and the two elevator cars can be adjusted relative to each other advantageously. 
         [0005]    In the design of the elevator system, the elevator car support can advantageously be arranged in an elevator shaft, a drive motor unit being provided which serves to actuate the elevator car support. As a result, the elevator car support can be displaced along the travel path provided. The elevator car support can hereby be suspended from a traction means connected to the elevator car support. The traction means can hereby be guided in a suitable fashion over a drive pulley of a drive motor unit. As well as having the function of transmitting the force or the torque from the drive motor unit to the elevator car support in order to actuate the elevator car support, the traction means can here also have the function of carrying the elevator car support. Actuation of the elevator car support is hereby understood in particular as raising or lowering the elevator car support in the elevator shaft. The elevator car support can thus be guided in the elevator shaft by one or more guide rails. 
         [0006]    It is advantageous that sheaves, about which the belt is guided, are attached to the first elevator car, that at least one sheave, about which the belt is guided, is attached to the elevator car support, and that the belt with the sheaves attached to the first elevator car and the sheave attached to the elevator car support forms a pulley system for adjusting the first elevator car. As a result, the torque applied by the drive unit to adjust the first elevator car can be reduced. As a result, the power required by the drive unit can be reduced. 
         [0007]    An optimized design is possible as a result of the interaction of the belt with the sheaves. In the case of multiple suspension from a belt, a belt with tension members which have a diameter of 1.7 mm, in combination with a sheave pitch diameter of 87 mm, can for example be formed, the belt height being approximately 3 mm. By way of comparison, in the case of a design with a cable hoist, the cable diameter is for example 8 mm and the pitch diameter of the cable pulley 240 mm. The structural space required is thus considerably reduced. 
         [0008]    It is advantageous that the second elevator car is arranged adjustably on the elevator car support, that the second elevator car can be adjusted relative to the elevator car support by the drive unit by means of the belt, and that, when the first elevator car and the second elevator car are adjusted relative to the elevator car support, the first elevator car and the second elevator car can be adjusted in opposing directions of adjustment. Moreover, it is hereby advantageous that sheaves, on which the second elevator car is suspended via the belt, are arranged on the elevator car support. The two elevator cars can thus be adjusted relative to each other simultaneously by driving the belt. Because the two elevator cars are adjusted in opposite directions, the speeds of the adjusting movements of the two elevator cars are added together in terms of a change in the distance between the two elevator cars. 
         [0009]    It is advantageous that the belt has a first side and a second side averted from the first side, and that the first side serves as a contact side on which the belt is guided about a drive wheel of the drive unit and about sheaves and with respect to which the belt is deflected, and that the second side serves as a free back side with respect to which the belt is at least substantially not deflected. As a result, reverse deflections in the belt can be at least largely avoided. However, one or more guide sheaves can be provided which interact with the free back side of the belt in order to guide the belt. Such a guide sheave can, for example, be arranged on the elevator car support. Specifically, the belt can be guided in the same direction about the drive wheel and the sheaves. This design is especially advantageous in the case of a profiled belt. 
         [0010]    In particular, in the case of the belt being guided in the same direction, a first end of the belt is connected to a cross-member of the elevator car support. The belt is guided from its first end to at least two sheaves which are fastened to the first elevator car. The belt is also guided to at least two sheaves which are fastened to the cross-member. The belt is guided onwards downwards along the side of the first elevator car. Between its first end and the sheaves attached to the cross-member, the belt thus forms a loop in which the first elevator car is suspended. In such a guide arrangement for the belt, the belt is deflected about the sheaves substantially in the same direction. 
         [0011]    In a further embodiment of the guidance of the belt in the same direction, two additional sheaves are fastened to the cross-member and two additional sheaves to the first elevator car. The first end of the belt is likewise hereby connected to the cross-member and, as described above, guided to two sheaves on the first elevator car and then to two sheaves on the cross-member, the belt forming a first loop. The belt is guided onwards to the two additional sheaves on the first elevator car and from there to the two additional sheaves on the cross-member. The belt thus forms a second loop in which the first elevator car is suspended. Lastly, the belt is guided downwards along the side of the first elevator car. The arrangement of the additional sheaves on the cross-member and on the elevator car is designed in such a way that the two loops of the belt are guided so that they do not clash. This can be achieved by the additional sheaves on the first elevator car being arranged respectively offset horizontally and/or vertically on the cross-member. Three or more loops can be formed by arranging other sheaves on the cross-member and on the first elevator car. 
         [0012]    In a corresponding fashion, the second elevator car can be suspended in the same direction in one or more loops of the belt on a further cross-member. For this purpose, at least two sheaves are fastened to the second elevator car and a second end of the belt is connected to the further cross-member. The belt is guided from its second end to the two sheaves on the second elevator car and from there upwards along the side of the second elevator car. A second and further loops can in each case be formed by means of two additional sheaves on the further cross-member and by means of two additional sheaves on the second elevator car. 
         [0013]    It is, however, also advantageous that the belt has a first side and a second side averted from the first side, that the first side serves as a first contact side on which the belt is guided about a drive wheel of the drive unit and about sheaves and with respect to which the belt is deflected, and that the second side serves as a second contact side with respect to which the belt is guided about sheaves and with respect to which the belt is deflected. As a result, the space required for the arrangement of the belt and the sheaves inside the elevator car support can be optimized. A desired pulley system can optionally also be formed with a reduced number of sheaves. This design is especially suitable for a flat belt or a belt that is profiled on both sides. 
         [0014]    It is advantageous that the belt has at least one rib on at least one contact side. The rib can specifically hereby have a V-shaped profile. Multiple ribs are preferably formed on the contact side and are each at least approximately V-shaped. Other forms for the profile of the rib are also possible. The rib can, for example, have a trapezoidal profile. 
         [0015]    It is also advantageous that a further belt is provided which holds the first and second elevator car from below. A first end of the further belt is hereby connected to the elevator car support and a second end of the further belt is connected to the elevator car support. In particular, each end is connected to a cross-member of the elevator car support. The further belt holds from below the first and second elevator car in each case on two sheaves which are each fastened to an associated elevator car. The further belt thus represents a bottom tensioning means that prevents the first and second elevator car from jumping in the event of an abrupt stop. As a result, even in the event of emergency braking, it is ensured that the first and the second elevator car remain essentially constantly in a stationary position in relation to the elevator car support. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0016]    Preferred exemplary embodiments of the invention are explained in more detail in the following description with the aid of the attached drawings, in which corresponding elements are provided with matching reference numerals. In the drawings: 
           [0017]      FIG. 1  shows a schematic representation of an elevator system in accordance with a first exemplary embodiment of the invention; 
           [0018]      FIG. 2  shows a schematic representation of the section of an elevator system which is labeled II in  FIG. 1  in accordance with a second exemplary embodiment; and 
           [0019]      FIG. 3  shows a schematic representation of the profile of a belt for an elevator system in accordance with a possible design. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]      FIG. 1  shows an elevator system  1  with at least one elevator car support  2  which can be displaced in a travel space  3  provided for the travel of the elevator car support  2 . The travel space  3  can, for example, be provided in an elevator shaft of a building. 
         [0021]    The elevator car support  2  is suspended via multiple sheaves  5 ,  6  from a traction means  8 . For greater clarity, the passage of the traction means  8  between the sheaves  5 ,  6  has not been shown in  FIG. 1 . In a common design, the traction means  8  is guided directly from the sheave  5  to the sheave  6 . The traction means  8  is moreover guided about a drive pulley  9  of a drive motor unit  10 . The elevator car support  2  is displaced upwards or downwards through the travel space according to the current direction of rotation of the drive pulley  9 . 
         [0022]    A first elevator car  11  and a second elevator car  12  are arranged on the elevator car support  2 . The two elevator cars  11 ,  12  can hereby be adjusted relative to the elevator car support  2 . 
         [0023]    Cross-members  13 ,  14 ,  15 , connected to longitudinal members  16 ,  17  of the elevator car support  2 , are formed on the elevator car support  2 . The sheaves  5 ,  6  are arranged on the cross-member  13 . Moreover, a drive unit  18  is attached to the cross-member  13 . The drive unit  18  serves to drive a belt  19 . To do this, the belt  19  is guided about a drive wheel  20  of the drive unit  18 . One end  21  of the belt  19  is connected to the cross-member  13 . Another end  22  of the belt  19  is connected to the cross-member  14  of the elevator car support  2 . A longitudinal direction  24  of the elevator car support  2  is determined according to a direction of travel  24 . The longitudinal members  16 ,  17  of the elevator car support  2  are hereby oriented along the longitudinal direction  24 . The cross-members  13  to  15  are arranged between the longitudinal members  16 ,  17 , perpendicularly with respect to the longitudinal direction  24 . 
         [0024]    In a region  25  between the cross-member  13  and the first elevator car  11 , the belt  19  is guided back and forth multiple times between the cross-member  13  and the first elevator car  11 . Starting from the fixed end  21 , the belt  19  is hereby guided initially counter to the longitudinal direction  24  to a sheave  26  fastened on the first elevator car  11 . The belt  19  is then guided about the sheave  26  and in the longitudinal direction  24  to a sheave  27  fastened to the cross-member  13 . Moreover, the belt  19  is then guided onwards, counter to the longitudinal direction  24 , to a sheave  28  fastened to the first elevator car  11 . The belt  19  is guided, transversely with respect to the longitudinal direction  24 , from the sheave  28  to a further sheave  29  fastened to the first elevator car  11 . The belt  19  is guided from the sheave  29 , initially in the longitudinal direction  24 , to a sheave  30  fastened to the cross-member  13 , and then in the opposite direction to the longitudinal direction  24  to a sheave  31  fastened to the first elevator car  11 , and then in the longitudinal direction  24  to the drive wheel  20  of the drive unit  18 . The belt  19  is hereby deflected both with respect to its first side  32  and with respect to its second side  33 . The first side  32  of the belt  19  is hereby applied to the drive wheel  20  of the drive unit  18 , whilst the second side  33  faces away from the drive wheel  20  in the region of the drive wheel  20 . 
         [0025]    In this exemplary embodiment, the first elevator car  11  is arranged on a first member  34  which is guided in the longitudinal direction  24  on the elevator car support  2 . Moreover, the second elevator car  12  is arranged on a second member  35  which is guided in the longitudinal direction  24  on the elevator car support  2 . 
         [0026]    The belt  19  runs from the drive wheel  20  of the drive unit  18  counter to the longitudinal direction  24  to a guide sheave  36 . Moreover, the belt  19  is guided about the guide sheave  36  and further guide sheaves  37 ,  38 . The guide sheaves  36  to  38  are connected to the elevator car support  2 . The belt  19  is guided onwards from the guide sheave  38  to a guide sheave  39  which is connected to the cross-member  14 . 
         [0027]    In a region  40 , the belt  19  is guided multiple times in and counter to the longitudinal direction  24 . The belt  19  is hereby guided back and forth between the cross-member  14  and the second elevator car  12 . The belt  19  thus runs from the guide sheave  39  counter to the longitudinal direction  24  to a sheave  41  which is connected to the second elevator car  12 , then in the longitudinal direction  24  to a sheave  42  connected to the cross-member  14 , and then counter to the longitudinal direction  24  to a sheave  43  connected to the second elevator car  12 . The belt  19  is moreover guided, transversely with respect to the longitudinal direction  24 , along the second elevator car  12  from the sheave  43  to a sheave  44  connected to the second elevator car  12 . The belt  19  is guided in the longitudinal direction  24  from the sheave  44  to a sheave  45  connected to the cross-member  14 , then counter to the longitudinal direction  24  to a sheave  46  connected to the second elevator car  12 , and then onwards in the longitudinal direction  24  to the cross-member  14 , the end  22  being connected to the cross-member  14 . 
         [0028]    Moreover, in this exemplary embodiment a further belt  50  is provided which is designed in a corresponding fashion to the belt  19 . One end  51  of the belt  50  is hereby connected to the cross-member  14 . Another end  52  of the belt  50  is connected to the cross-member  15 . In this exemplary embodiment, the belt  50  has the function of holding the first elevator car  11  and the second elevator car  12  from below. Consequently, when for example an emergency braking operation is initiated, whilst the elevator car support  2  moves upwards through the travel space  3 , the braking forces are reliably transmitted from the elevator car support  2  to the two elevator cars  11 ,  12 . 
         [0029]    Starting from its end  51 , the belt  50  is guided in the longitudinal direction  24  about a sheave  53  connected to the first member  34 . The belt  50  is then guided, transversely with respect to the longitudinal direction  24 , to a further sheave  54  connected to the first member  34 . The belt  50  is guided from the sheave  54  counter to the longitudinal direction  24  along the side of and past the second elevator car  12  to a sheave  55 . The sheave  55  is hereby connected to the cross-member  15 . The belt  50  is guided from the sheave  55  in the longitudinal direction  24  to a sheave  56  connected to the second member  35 . The belt  50  is guided from the sheave  56 , transversely with respect to the longitudinal direction  24 , to a sheave  57 . The belt  50  is guided from the sheave  57 , counter to the longitudinal direction  24 , to the cross-member  15 , the end  52  being connected to the cross-member  15 . 
         [0030]    In this arrangement, the two elevator cars  11 ,  12  are suspended from the belt  19 . A pulley system for the first elevator car  11  is hereby formed in the region  25 . A pulley system for the second elevator car  12  is moreover formed in the region  40 . Because the two pulley systems have the same transmission ratios, the adjustment travels for the first elevator car  11  and the second elevator car  12  are also the same. The drive unit  18  is also, to a certain extent, arranged between the two pulley system arrangements. Thus, if the length of the belt  19  in the region  25  is shortened, the belt  19  in the region  40  is lengthened, and vice versa. If the first elevator car  11  is adjusted by the pulley system arrangement in the region  25  in the longitudinal direction  24  relative to the elevator car support  2 , the second elevator car  12  is thus adjusted relative to the elevator car support  2  counter to the adjusting direction  24 . The same applies in reverse. The elevator cars  11 ,  12  are thus always adjusted in directly opposite directions. It should hereby be noted that the sheaves  27 ,  30  of the pulley system arrangement in the region  25  are arranged immovably on the elevator car support  2 , and that the sheaves  42 ,  45  are arranged, likewise immovably, on the elevator car support  2  via the cross-member  14 . Moreover, coordination with the belt  50  is thus ensured since shortening the belt  50  between the end  52  and the sheave  55  lengthens the distance between the sheave  55  and the end  51  by precisely the required amount. As a result, it can in particular be achieved that a predetermined tensile stress of the belt  50  is always maintained. For this purpose, the sheave  55  can be subjected to the action of a spring element  58 . 
         [0031]    The belt  19  and the belt  50  serve different functions so that these different loads can be applied. It is hereby possible to adapt to the respective example of application in different ways. For example, it is possible to provide four belts  19 , guided in parallel, instead of a single belt  19 . It is also possible to provide two belts  50 , guided in parallel, instead of a single belt  50 . The belts  19 ,  50  can hereby be guided via sheaves  26  to  31 ,  41  to  46 ,  53  to  57  and guide sheaves  36  to  39  which are designed with a corresponding width. As a result, uniformly designed belts can be used as the belts  19 ,  50 . In this embodiment, the belt  19  is deflected both with respect to its first side  32  and to its second side  33 . For example, the belt  19  is deflected at the sheave  31  with respect to the second side  33 , whilst it is deflected at the sheave  30  with respect to the first side  32 . A deflection with respect to both sides  32 ,  33  thus occurs in the pulley system arrangements in the regions  25 ,  40 . This means that a deflection and a reverse deflection of the belt  19  occur as part of the belt guidance. However, it is hereby possible to optimize the available space and the total required length of the belt  19 . 
         [0032]    Because the elevator cars  11 ,  12  are each tensioned between the belts  19 ,  50 , a high degree of stability of the elevator car support  2  with the elevator cars  11 ,  12  can be obtained. As a result, it is also possible that the first elevator car  11  has a relatively great height and/or that the second elevator car  12  has a relatively great height. The extents of the elevator cars  11 ,  12  in the longitudinal direction  24  can thus be preset to be relatively great. Moreover, a lateral spacing of the elevator cars  11 ,  12  from the longitudinal members  16 ,  17  can be reduced. It is hereby also advantageous that the belt  19  or the belt  50  can be guided close to the longitudinal members  16 ,  17 , as a result of which the remaining space for the elevator cars  11 ,  12  is increased further. A large part of the available shaft cross-section in the travel space  3  can thus be used by the elevator cars  11 ,  12 . 
         [0033]      FIG. 2  shows a schematic representation of the section of the elevator system  1  which is labeled II in  FIG. 1  in accordance with a second exemplary embodiment. In this exemplary embodiment, a further sheave  60  is arranged next to the sheaves  26 ,  28  on the first elevator car  11 . Furthermore, a further sheave  61  is arranged next to the sheaves  29 ,  31 , on the first elevator car  11 . Moreover, a further sheave  62  is arranged next to the sheave  27  on the cross-member  13 . Furthermore, a further sheave  63  is arranged next to the sheave  30  on the cross-member  13 . In this exemplary embodiment, an alternative guidance of the belt  19  in the region  25  is shown for implementing a pulley system. In this pulley system arrangement, the belt  19  is guided clockwise from its end  21  about the sheave  60 , then the sheave  61 , the sheave  63 , the sheave  62 , the sheave  28 , the sheave  29 , the sheave  30 , the sheave  27 , the sheave  26 , the sheave  31 , a guide sheave  64  arranged on the cross-member  13 , and then a guide sheave  65  which is also arranged on the cross-member  13 . The belt  19  is then guided from the guide sheave  65  counter to the longitudinal direction  24  downwards along the side of the first elevator car  11 . A pulley system arrangement is thus formed in the region  25 , in which the belt  19  bears always with its first side  32  against the individual sheaves  26 ,  27 ,  28 ,  29 ,  30 ,  31 ,  60 ,  61 ,  62 ,  63 ,  64 ,  65 . The belt  19  is thus always deflected with respect to its first side  32 . Reverse deflections are thus avoided or at least substantially avoided. The belt  19  can, however, also bear against individual guide sheaves  36  with its second side  33  and thus also be deflected somewhat with respect to the second side  33 . The guide sheave  64  can also be replaced by the drive wheel  20  of the drive unit  18 . 
         [0034]    The belt  19  can thus only be guided on the first side  32  serving as the front side  32 , the second side  33  serving as a free back side  33 . Depending on the design of the belt  19 , the load on the belt  19  can consequently be reduced. 
         [0035]    A pulley system arrangement can be formed in a corresponding fashion in the region  40  of the second elevator car  12 . 
         [0036]      FIG. 3  shows a schematic representation of a profile of the belt  19  in accordance with a possible design. The belt  19  can be designed as a V-ribbed belt and have multiple ribs  70 ,  71 ,  72 . Each of the ribs  70  to  72  can hereby have an approximately V-shaped cross-section. In this exemplary embodiment, the design with ribs  70  to  72  is provided on the first side  32 . The second side  33  is flat in design. The belt  19  is thus profiled on one side, the first side  32 . The first side  32  hereby serves as a contact side. A belt of this type is used, for example, in the second exemplary embodiment illustrated with the aid of  FIG. 2 . 
         [0037]    The belt  19  can alternatively also be profiled on both sides  32 ,  33 . Ribs can hereby be formed on the second side  33  as well, in a corresponding fashion to the ribs  70  to  72 . A belt  19  of this type is preferably used in the first exemplary embodiment described with the aid of  FIG. 1 . 
         [0038]    It is moreover possible that a belt  19  designed as a flat belt  19  is used. In the case of such a flat belt  19 , the first side  32  is also flat in design. The first side  32  is then hereby designed in a corresponding fashion to the second side  33 , as illustrated in  FIG. 3 . However, a certain surface structure can hereby be provided in order to improve the friction when the belt interacts with the drive wheel  20  of the drive unit  18 . In this embodiment, either one of the sides  32 ,  33  or both sides  32 ,  33  can thus serve as contact sides. 
         [0039]    Moreover, the belt  19  can also be designed as a toothed belt  19 . 
         [0040]    In the case of a belt  19  that is flat in design on at least one of its sides  32 ,  33 , the flat side  32 ,  33  is preferably guided over a crowned sheave or the like. The guide surface of the crowned sheave is hereby convex in design. Also, the convex guide surface is preferably bordered by lateral shoulders in order to guide the belt  19 . 
         [0041]    The invention is not limited to the exemplary embodiments described. 
         [0042]    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.