Abstract:
An elevator apparatus including a position determination apparatus for determining the position of an elevator car inside an elevator shaft, the position determining apparatus including a marking unit for marking a position of the elevator car, and a detection unit for detecting the marking unit, the marking unit being arranged on one of the shaft doors and the detection unit being arranged on the associated car door or vice versa for the purpose of improved installation.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit under 35 USC §119(a)-(d) of European Application No. 11 006 891.3 filed Aug. 23, 2011, and claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application 61/526,390, filed Aug. 23, 2011, the entireties of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to an elevator apparatus for conveying persons and/or items, a position determination apparatus, particularly for an elevator, an elevator door and a building. 
       BACKGROUND OF THE INVENTION 
       [0003]    Various position determination apparatuses for elevators are known in the prior art. So-called code bands which are continuously read by a sensor fitted to the elevator car are sometimes fitted inside the elevator shaft. 
         [0004]    Reference is also made to the applicant&#39;s own applications EP 11 005 240 (U.S. Ser. No. 13/530,168—Attorney Docket No. 885 — 209) and EP 11 005 232 (U.S. Ser. No. 13/173,594—Attorney Docket No. 885 — 210). 
       SUMMARY OF THE INVENTION 
       [0005]    The object of the invention is to provide a position determination apparatus and an elevator apparatus which enable improved installation. 
         [0006]    An elevator apparatus according to the present invention is distinguished by the fact that the corresponding marking unit is arranged on one of the shaft doors and the detection unit is arranged on the associated car door or, conversely, the marking unit is arranged on one of the car doors and the detection unit is arranged on the associated shaft door. 
         [0007]    The elevator apparatus according to the present invention is used, in principle, to convey persons and items, the elevator or the car being guided inside an elevator shaft. The elevator shaft itself is in a three-dimensional structure comprising at least two floors, in particular in a building or the like. It is also conceivable for the three-dimensional structure to be, for example, a vehicle which comprises a plurality of floors, for example a ship. In principle, the three-dimensional structure may also be a type of framework. All possible three-dimensional structures in the sense of the invention in which an elevator can be used for conveyance between a plurality of floors are conceivable here. 
         [0008]    The conveyance itself is effected in an elevator car which can accommodate the persons and/or items to be conveyed. The car in turn has a car door which can be opened and closed, in which case opening of the car door makes it possible to access the car, that is to say persons can get in or out or items can be put into the car or can be conveyed out of the car. 
         [0009]    The elevator shaft has at least one shaft opening. Such shaft openings are generally arranged in the region or at the level of the individual floors. For example, it is conceivable for one shaft opening to be arranged per floor, but it is also possible, for example, to arrange two shaft openings on one floor, in particular on opposite sides of the car, with the result that the car can be accessed, for instance from two opposite sides. Access in the sense of the invention means that persons can get in or out of the car, for example, or corresponding items can be loaded into or unloaded from the car. In addition, at least one shaft door is arranged at the corresponding shaft opening. Such a shaft door closes the shaft opening, in particular even when there is currently no elevator car at the level of the shaft opening. This makes it possible to prevent persons from inadvertently being able to fall into the elevator shaft, inter alia. 
         [0010]    If the elevator car stops at a particular floor on its journey through the elevator shaft, it accordingly stops at the level of a special shaft opening which is associated with this floor. The elevator car then reaches a predetermined stopped position in the region of the shaft opening, this stopped position being selected in such a manner that it is possible to access the elevator shaft and thus the car. In principle, doors open and close only when the elevator car is in the stopped position; exceptions in emergency situations in which doors may possibly also be opened are conceivable. 
         [0011]    The elevator car itself in turn has at least one car door for providing access to the elevator car. In the stopped position, a shaft door is respectively associated with the car door. The car door and the associated shaft door overlap at least partially with respect to the shaft opening and the car opening. The car door associated with a shaft door is generally arranged in such a manner that, for example in the closed state in the stopped position, persons who are in the car see the car door but do not see the associated shaft door which is then arranged behind the car door. Persons in turn who are outside the car on the corresponding floor usually only see the shaft door when it is closed during the stopped position of the car. 
         [0012]    In order to make it possible to access the elevator shaft and the elevator car, the car and shaft doors must be opened. In addition, the shaft door and the associated car door generally move in the same direction. 
         [0013]    The car door is movably mounted on the car, while the shaft door is movably mounted on the shaft itself, to be precise in the region of the shaft opening. A narrow gap, a gap opening, is also usually produced between the car door and the shaft door in the stopped position. 
         [0014]    One shaft door may, in principle, be arranged at a shaft opening, but a plurality of shaft doors may also be provided. The elevator doors are usually accordingly fitted to the elevator car in a mariner matching the door arrangement at the shaft openings. It is conceivable for two shaft doors to be arranged at the shaft opening, for example, which doors each move in the opposite direction with respect to one another (sliding door) during opening and closing. Elevator doors which analogously correspond to the shaft opening doors, that is to say likewise two elevator doors for example, which move in the same manner as the (respectively associated) shaft doors during opening and closing, that is to say the shaft doors also move in the opposite direction with respect to one another, can likewise accordingly be provided in an associated elevator car. In this manner, a car door is accordingly associated with each shaft door. 
         [0015]    An elevator apparatus according to the invention also comprises a position determination apparatus for determining the position of the elevator car inside the elevator shaft. The position determination apparatus is thus used to determine an item of shaft or floor information. The position determination apparatus comprises a marking unit for marking the respective position and also a detection unit for detecting and/or reading the marking unit. 
         [0016]    As a result of the measure whereby the marking unit is arranged on one of the shaft doors and the detection unit is arranged on the associated car door or vice versa, various advantages with regard to installation can be achieved in principle. 
         [0017]    In particular, such an apparatus can be pre-installed. In commercially available elevator apparatuses, it is usually necessary for parts of the position determination apparatus or the entire position determination apparatus to be able to be installed only when the elevator car has been set up in the shaft because only in this manner is it possible to make the exact position information determinable with the aid of marking units in a referenced manner. This is because, if inaccuracies occur during construction or installation or the structure shifts in a non-uniform manner after a certain amount of time (that is to say “the structure settles”), as is frequently the case in buildings, the actual position no longer corresponds to the originally applied markings and the position determination apparatus generally operates inaccurately. However, it is particularly important for the shaft and car doors to respectively be able to assume a comparatively defined position with respect to one another in the stopped position. However, the shaft opening and the car can then be changed to a corresponding predetermined relative position with respect to one another if the reference for the corresponding positions is accurate enough. Such accurate adjustment is enabled when the marking unit and the detection unit are each in the corresponding sections which must be related to one another in terms of position detection. 
         [0018]    Another advantage is that such an apparatus can also be retrofitted well. Costs can thus also be saved since lower costs overall have to be expended, in principle, for corresponding installation and comparatively simple replacement of the position determination apparatus is, however, additionally also possible. 
         [0019]    The elevator apparatus according to the invention also has the advantage that the sensors can be additionally protected. Since detection units, that is to say sensors, which are generally used in such elevator systems are exposed to very high loads on a construction site, the sensors can sometimes be damaged. The risk of the sensor being affected is present, in particular, when sensitive sensors are used. Finally, it is often also necessary for such sensors to be installed by special experts, for example, sensor engineers or electronics engineers. Therefore, it is particularly advantageous if the corresponding detection units and sensors can be pre-installed and can be installed when manufacturing the elevator, for example, in the factory itself. On the one hand, this measure also makes it possible to save costs since no experts have to be specifically called to the construction site in order to install the sensors and, on the other hand, installation at the factory can then be carried out under less adverse circumstances than would possibly be the case on the construction site. 
         [0020]    Furthermore, it is usually advantageous for the detection unit and the marking unit to be arranged on mutually facing sides of the car door and the associated shaft door, respectively. This makes it possible for the detection unit and the marking unit to be held without an obstacle between them. This measure also accordingly makes it easier to read the marking unit. For the rest, in this embodiment, neither the detection unit nor the marking unit is generally visible to the user of the elevator because the mutually facing sides of the car door and the associated shaft door are precisely on the side facing away from the respective user. Although, for example, the side on which the marking unit or the detection unit is fitted to the shaft door faces a person in the car, this side is in turn concealed for the user in the car by the associated car door. Only the narrow gap opening between the mutually associated cars and shaft doors then generally lies between the detection unit and the marking unit. Detection is therefore advantageously effected only over a short distance and can consequently also be effected with the corresponding degree of precision. 
         [0021]    For the rest, an exemplary embodiment of the invention comprises a control unit for controlling the journey of the elevator car. In the present sense, the term “control” means open-loop control and/or closed-loop control. The control unit can then preferably be designed in such a manner that the shaft door and the associated car door can be moved in a substantially synchronous manner when opening and/or closing the shaft door and the car door. However, it is not absolutely necessary for this to take place in an absolutely synchronous manner. The position determination apparatus is preferably connected to a control unit or electronic unit, with the result that the journey of the car to the corresponding floor is subjected to open-loop/closed-loop control according to the floor selected by the user, the floor information being determined by the position determination apparatus. 
         [0022]    In principle, it is conceivable for the shaft door and/or the car door to be in the form of solid doors from a solid body. However, this is usually not required, on the one hand, and is usually even undesirable, on the other hand, since such solid doors have a high weight and are also considerably more cost-intensive. Solid doors are also usually more difficult to install and transport. For example, a shaft or car door may only consist only of walls, for example may be produced from sheet metal such as sheet steel. 
         [0023]    In one preferred embodiment of the invention, a recess and/or indentation may be provided in shaft doors and/or associated car doors on mutually facing sides, which recess and/or indentation uncover(s) an intermediate space between the shaft door and the associated car door. Such a recess/indentation may be formed in a wide variety of ways. 
         [0024]    In the case of a door formed from walls (that is to say not from solid material), the walls may be formed, for example, in such a manner that they do not completely delimit or surround the door to the outside. An opening, a recess, is present to some extent in associated shaft or car doors on the mutually facing sides thereof. However, it is also possible for the wall not to be interrupted on the respective facing sides but rather to be deformed away from the respectively associated door. For example, the car door is accordingly provided with a deformation, an indentation, in the direction of the car, while the shaft door could be provided with a protrusion away from the car, for example. In addition to the gap openings which are present anyway between associated shaft and car doors, this produces a further space which is thus uncovered, that is to say a larger intermediate space between the two. 
         [0025]    However, such recesses can also be provided when shaft doors and car doors are solid. Such a recess may, in principle, also be removed from the solid material. It is also conceivable for such recesses to be provided either only on one car door or only on one shaft door, only on a few shaft doors or only on some car doors or else on all shaft doors or all car doors. 
         [0026]    In order to be able to provide a particularly space-saving marking unit, the latter may be in the form of adhesive tape in one embodiment variant of the invention. This also usually means simple production of such a marking unit and installation which is also simple. Additional markers which indicate where the marking unit in the form of adhesive tape must be affixed may also have already been applied to the corresponding doors. This measure possibly facilitates installation. Particularly when there is only one gap opening between the car and the shaft doors, it is advantageous to provide a correspondingly thin marking unit, such that no collisions and no wear can result. The design in the form of adhesive tape makes it possible to implement the marking unit in a particularly simple manner. It is also conceivable to provide the marking unit in the form of a plate. 
         [0027]    In one development of the invention, the marking unit is also in the form of a carrier of a 2D code. It is also conceivable to also use a simple one-dimensional barcode. However, a 2D code also has the advantage that greater coding/information density becomes possible. The 2D code may be composed of different segments in which different information is coded. In particular, the segments may contain position information or floor information. In addition, the marking unit can be easily produced in an advantageous manner since a 2D code can be easily printed on, for example, onto an adhesive tape. Consequently, the marking unit can be very thin, that is to say can be designed and arranged in a space-saving manner. 
         [0028]    Particularly when the marking unit is in the form of a barcode or a 2D code, it is advantageous for the detection unit to be in the form of an optical sensor. In the meantime, optical sensors can be produced in a comparatively cost-effective manner. They make it possible to precisely and reliably detect and read marking units. In addition, optical sensors can also operate in a correspondingly rapid manner and can also be evaluated in a particularly rapid manner, such that a result in terms of the position information can be present in the control unit within a very short time. 
         [0029]    If a recess is also provided in shaft and car doors, this measure enables not just a simplified structure and corresponding advantages with regard to the shaft and car doors themselves. In addition, the additional space which is gained and is provided by the intermediate space can be used to accommodate further apparatuses or structural units of the elevator. For this reason, it is advantageous, in one development of the invention, to arrange the marking unit and/or the detection unit in the intermediate space formed by the recess. This makes it possible to avoid the thickness of the corresponding doors also being increased by fitting the marking unit and/or detection unit or makes it possible for the thickness of the doors to be increased only negligibly. Even when it is narrow and compact, the detection unit will usually have at least a certain thickness and will possibly also be thicker than an existing gap opening between the car door and the associated shaft door even if any recesses or indentations were not present. In any case, the space gained by the recess/indentation or by the intermediate space can be used for this purpose. 
         [0030]    However, such elevator systems generally do not just require a sensor system for position determination. In the case of elevators, the objective is usually to prevent persons from being caught or squashed in the access region of the elevator car. If, for example, a person reaches into the still open gap of a closing door, it is necessary to stop the movement of the door as quickly as possible and possibly for the door to also open again. It is particularly advantageous if the corresponding detection unit additionally comprises a further optical sensor for detecting persons and/or items. 
         [0031]    In one exemplary embodiment of the present invention, such a further optical sensor for detecting persons and/or items may be in the form of a light barrier sensor for emitting and/or receiving light barrier signals. Such a light barrier may likewise be implemented in various ways. 
         [0032]    For example, a transmitting unit which emits optical signals may be provided in the detection unit. A reflection element, for example a metal lug with which the optical signal is reflected and passes to a receiving unit in the detection unit again, can then be fitted at a predefined location, for example. If this signal is detected, this means that there is no person/no item in the light barrier. Otherwise, that is to say if a person and/or an item enter(s) the light barrier, the latter is interrupted and the optical signal does not pass back to the receiving unit or the detection unit again. In this case, a corresponding signal is transmitted to the control unit and causes a movement of doors (shaft doors and/or car doors) to be stopped or not to begin at all in the first place and causes the doors to possibly also open again. For better reflection, reflective stickers or labels may be applied to the corresponding reflection units, for example. 
         [0033]    It is conceivable, for example, for the reflection unit to be arranged on the elevator car and/or on the car door, preferably in the intermediate space formed by the recess, and/or on the shaft door, preferably in the intermediate space formed by the recess. The detection unit may thus be arranged/designed in such a manner that it emits optical signals which are oriented parallel to the access opening and run through the gap opening. In particular, it is conceivable for the detection unit or at least one part of the detection unit to project into the gap opening in such a manner that a corresponding optical signal for detecting persons and/or items inside the gap opening is passed from there. That is to say, if the region inside the gap opening is monitored, precisely that region which is critical for monitoring is sensed thereby. 
         [0034]    In principle, the entire door region can be sensed, for example in the form of a grid. In this case, monitoring must generally be carried out, in spatial terms, at certain intervals, with the result that it is possible to at least detect items starting from a certain size. In principle, it is also conceivable for the monitoring beams to be emitted in a radial manner. 
         [0035]    Instead of or in addition to a light barrier, such an optical sensor for detecting persons and/or items may also be in the form of a so-called time-of-flight sensor (abbreviation: TOF sensor). In the case of such a sensor, the propagation time of an emitted signal, which is in turn at least partially reflected and passes to the detection unit again, is measured. Such signals may be effected, for example, using infrared light but, in principle, also with visible light (wavelength range of visible light: approximately 400 nm-800 nm). In this case, a special signal which changes only very slowly with respect to the oscillation duration of the light, that is to say a (very) low-frequency signal in comparison for example, can be modulated onto the corresponding emitted optical signal, for example. With a low-frequency signal which has been modulated on, the phase shift with respect to the emitted signal can then be determined after detecting a reflected portion. It is thus possible to determine the propagation time. If items or persons now enter the region being monitored, the propagation distance is shortened and the propagation time of the emitted signal is thus also shortened. 
         [0036]    A position determination apparatus according to the invention is accordingly designed to determine the position of an elevator car inside the elevator shaft for an elevator apparatus according to the invention or an exemplary embodiment of the elevator apparatus according to the invention and is distinguished, in particular, by the fact that the marking unit can be fitted to one of the shaft doors and the detection unit can be fitted to the associated car door or vice versa. An elevator door according to the invention, that is to say a shaft door or a car door in particular, is distinguished by the fact that a position determination apparatus or an embodiment according to the invention is provided. 
         [0037]    A building according to the present invention is also distinguished by the fact that an elevator apparatus according to the invention or an embodiment variant of the elevator apparatus according to the invention is present. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0038]    Exemplary embodiments of the invention are illustrated in the drawings and are explained in more detail below while stating further advantages and details. 
           [0039]      FIG. 1  shows a diagrammatic illustration of an elevator apparatus having sliding doors according to the invention; 
           [0040]      FIG. 2  shows a diagrammatic illustration of an elevator apparatus according to the invention having a telescopic sliding door; 
           [0041]      FIG. 3  shows a diagrammatic illustration of an elevator apparatus having a sliding door and a light barrier according to the invention; 
           [0042]      FIG. 4  shows a diagrammatic illustration of a further elevator apparatus having a sliding door and a light barrier according to the invention; 
           [0043]      FIG. 5  shows a diagrammatic illustration of an elevator apparatus having a single door and an additional light barrier according to the invention; 
           [0044]      FIG. 6  shows a diagrammatic illustration of an associated shaft door and car door with recesses and with a marking and detection unit according to the invention; 
           [0045]      FIG. 7  shows a diagrammatic illustration of the shaft door and car door according to the invention with a total of only one recess; 
           [0046]      FIG. 8  shows a diagrammatic illustration of the associated shaft door and car door with indentations according to the invention; 
           [0047]      FIG. 9  shows a diagrammatic illustration of the shaft door and car door with a recess and an indentation according to the invention; and 
           [0048]      FIG. 10  shows a diagrammatic illustration of how the code band is detected by the detection unit, in two views. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0049]      FIG. 1  shows a diagrammatic section through part of an elevator apparatus  1  in plan view in the region of a shaft opening  2 . The concrete walls  3  with the shaft opening  2  (already mentioned) between them and a shaft  4 , in which an elevator car  5  is in turn located and can be moved, are illustrated inter alia. The direction of movement runs perpendicular to the plane of the drawing in  FIG. 1 . A sliding door system  6  which makes it possible to access the car  5  through the shaft opening  2  is also provided. This sliding door system  6  in turn comprises two shaft doors  7   a  and  7   b.  These shaft doors  7   a  and  7   b  belong to the shaft and are fastened or movably mounted in the region of the shaft opening  2 . The car doors  8   a  and  8   b  are in turn movably mounted on the car  5  itself. The shaft door  7   a  is associated with the car door  8   a,  while the shaft door  7   b  is associated with the car door  8   b.    
         [0050]    During opening of the sliding door  6 , the doors associated with one another, that is to say the shaft door  7   a  and the car door  8   a,  move to the left in the drawing (cf. direction arrows L), while the shaft door  7   b  and the car door  8   b  move to the right (cf. direction arrows R). This movement is effected synchronously. A person who is inside the car  5 , for example, therefore only sees the car doors  8   a  and  8   b  when the sliding door  6  is closed, whereas a person who is on the floor on the other side of the sliding door  6  (that is to say at the top in the drawing) sees only the shaft opening doors  7   a  and  7   b.  During opening, the doors each move simultaneously to the left (namely the doors  7   a  and  8   a ) and to the right (the doors  7   b  and  8   b ). The reference symbol  9 ′ denotes the rolling plane in which the shaft doors  7   a  and  7   b  move, while the reference symbol  9 ″ denotes the rolling plane of the car doors ( 8   a  and  8   b ). These rolling planes  9 ′ and  9 ″ are each illustrated using dashed lines in the drawing. A gap opening  10  is situated between these rolling planes  9 ′ and  9 ″ and thus correspondingly also respectively runs between the car doors  8   a,    8   b,  on the one hand, and the shaft doors  7   a,    7   b,  on the other hand. 
         [0051]    The shaft opening doors  7   a,    7   b  and also the car doors  8   a,    8   b  each have associated recesses  11   a,    11   b  and  12   a,    12   b.  These recesses  11   a,    11   b,    12   a,    12   b  are in the form of openings inside the door sides which are respectively associated with one another. A code band  13  in the form of adhesive tape is arranged in the recess  11   a  in the shaft door  7   a.  An optical sensor in the form of a detection unit  14  is arranged on the inside of the associated car door  8   a  exactly opposite the shaft door  7   a  and the code band  13  in the stopped position. The optical sensor  14  has a greater thickness than the adhesive tape  13  but may be integrated in the door  8   a  by means of the recess  12   a  in such a manner that it does not project into the gap opening  10 . 
         [0052]    During the journey of the car  5 , all doors  7   a,    7   b,    8   a,    8   b  are closed. When the car  5  moves past the shaft opening  2 , the optical sensor  14  can read the code band  13  and can thus determine the position of the elevator car  5 . In particular, this makes it possible to provide a relatively accurate reference with respect to the shaft opening  2  and thus makes it possible to obtain an accurate item of position information. 
         [0053]      FIG. 2  in turn illustrates a similar situation, namely an elevator apparatus  101  with a shaft opening  102 , concrete walls  103 , a shaft  104  and a car  105  which moves in the shaft. However, in contrast to  FIG. 1 , the sliding door  106  is in the form of a telescopic sliding door. In this case, the shaft door  107   a  is arranged such that it is offset with respect to the shaft door  107   b  perpendicular to the displacement direction. The car doors  108   a  and  108   b  are likewise accordingly offset with respect to one another. Consequently, the associated doors, namely the shaft door  107   a  and the car door  108   a,  are closer to one another than the shaft door  107   b  and the shaft door  108   b.  Overall, the rolling planes  109 ′ and  109 ″ are broader since the shaft doors  107   a,    107   b  have to be accommodated beside one another in the open position (similarly the car doors  108   a  and  108   b ). There is a gap opening  110  between the rolling planes  109 ′ and  109 ″ which are illustrated using dashed lines. However, all doors  107   a,    107   b,    108   a,    108   b  can only travel to the right (direction of travel R) in the drawing. The control unit is designed such that the speed of travel of the doors  107   a  and  108   a  is faster than that of the doors  107   b  and  108   b,  such that both reach their end position during opening approximately equally quickly (similarly in the closing operation). The doors  107   a,    107   b,    108   a,    108   b  also each have corresponding recesses  111   a,    111   b,    112   a,    112   b,  in which case the code band  113  and the optical sensor  114  are each correspondingly arranged in the doors  107   a  and  108   a.  The terminating elements  115 ′ and  115 ″ which are respectively fitted to a concrete wall  103  and, in the case of reference symbol  115 ″, to the car  105  are used to prevent a person from being able to laterally intervene and thus being squashed, in particular while the car is moving. 
         [0054]      FIG. 3  shows a similar elevator apparatus  201  to that illustrated in  FIG. 1 . In the present case, an adhesive tape  213  is likewise arranged in the shaft door  207   a,  while a detection unit  214  is provided in the car door  208   a.  The arrows  216  illustrate how the detection unit  214  reads the code band  213 . A gap  210  is provided between the shaft doors  207   a,    207   b  and the car doors  208   a,    208   b.  However, the detection unit  214  projects into this gap opening. The detection unit  214  also comprises an optical sensor for detecting persons and/or items. This optical sensor which is integrated in the detection unit  214  emits light beams parallel to the direction of movement of the sliding doors, to be precise to the right along the arrow S in the drawing. An optical detector  217  is situated the light emitted by the light barrier. It is also conceivable for a reflection lug which reflects the optical signal emitted by the light barrier again to be arranged at the same location instead of an optical detector  217 . If the doors accordingly open to the right and to the left (displacement directions R and L), an ever larger gap through which the beams from the light barrier pass forms perpendicular to the gap opening  210  in the region between the mutually associated doors  207   a  and  208   a  and  207   b  and  208   b.    
         [0055]      FIG. 4  shows a similar elevator apparatus  301  to that in  FIG. 3 , but the adhesive tape is arranged on the car door  308   a,  the corresponding detection unit is arranged on the shaft door  307   a  and the light barrier detector  317  is accordingly arranged on the shaft door  307   b.  The light barrier has the light beam S, in which case a movement of the doors is prevented/stopped if S is interrupted. 
         [0056]      FIG. 5  in turn illustrates an elevator apparatus  401  (similar to that in  FIG. 3 ) in which only one shaft door  407  and only one car door  408  are provided. The light barrier has a detector  417 . In contrast to  FIG. 3 , however, the light barrier detector  417  is fastened to the rigid housing of the car  405  and not to a movable door. The two doors  407   a  and  408   a  can only be moved to the left (direction arrow L). The detector unit  414  which can be used to read the code band  413  and which also emits the optical signal S for the light barrier projects into the gap opening  410  in this case. The light barrier detector  417  accordingly projects to the same extent in an extension of the gap opening  410 . 
         [0057]      FIG. 6  shows a shaft door  507  and an associated car door  508  with a code band  513  on the shaft door  507  and a detector unit  514  on the car door  508 , both doors each having recesses  511 ,  512  in the sense of openings. 
         [0058]      FIG. 7  in turn shows a configuration in which the shaft opening door  607  has a closed peripheral wall, while the car door  608  has a recess  612  in the sense of an opening. The detector unit  614  is arranged in the recess  612 . There are a gap opening  610  and an intermediate space Z between the two doors. The code band is affixed to or on the shaft door  607 . 
         [0059]    In  FIG. 8 , the shaft opening door  707  and the car door  708  are in turn designed such that indentations  711  and  712  increase the size of the gap opening  710  in the corresponding region. The code band  713  and the detector  714  are respectively arranged in the indentations  711  and  712 . 
         [0060]    The double door illustrated in  FIG. 9  comprises a shaft door  807  and a car door  808  with detectors  813  and  814 , an indentation  811  being formed in the shaft door  807  and a recess  812  being formed in the car door. 
         [0061]      FIG. 10  likewise shows an elevator apparatus  901  according to the invention and a corresponding view A which outlines how the code band  913  is perceived from the point of view of the detector unit  914 . In this case, the detector unit  914  detects an image through the recesses or openings  911 ,  912  in the shaft and car doors  907 ,  908 , respectively, through which the code band  913  becomes visible through the gap (not described in any more detail here) between the associated doors. An edge of the car door  908  is consequently still visible on the outside in the view A, then, through the opening  912 , a view of the shaft door  907  with the opening  911  which in turn uncovers the view of the code band  913 . 
         [0062]    In principle, in one preferred embodiment of the invention, the marking unit is arranged on a shaft door and the detection unit is arranged on the associated car door. This embodiment can also generally be produced and installed in a more cost-effective manner. 
       LIST OF REFERENCE SYMBOLS 
       [0000]    
       
           1  Elevator apparatus 
           2  Shaft opening 
           3  Concrete wall 
           4  Shaft 
           5  Car 
           6  Sliding door (as a whole) 
           7   a  Shaft door 
           7   b  Shaft door 
           8   a  Car door 
           8   b  Car door 
           9 ′ Rolling plane of the shaft doors 
           9 ″ Rolling plane of the car doors 
           10  Gap opening 
           11   a  Recess 
           11   b  Recess 
           12   a  Recess 
           12   b  Recess 
           13  Code band 
           14  Optical sensor 
           101  Elevator apparatus 
           102  Shaft opening 
           103  Concrete wall 
           104  Shaft 
           105  Car 
           106  Sliding door (as a whole) 
           107   a  Shaft door 
           107   b  Shaft door 
           108   a  Car door 
           108   b  Car door 
           109 ′ Rolling plane of the shaft doors 
           109 ″ Rolling plane of the car doors 
           10  Gap opening 
           111   a  Recess 
           111   b  Recess 
           112   a  Recess 
           112   b  Recess 
           113  Code band 
           114  Optical sensor 
           115 ′ Side stop on the shaft 
           115 ″ Side stop on car 
           201  Elevator apparatus 
           207   a  Shaft door 
           207   b  Shaft door 
           208   a  Car door 
           208   b  Car door 
           210  Gap opening 
           213  Code band 
           214  Detector unit 
           216  Light 
           217  Light barrier detector 
           301  Elevator apparatus 
           307   a  Shaft door 
           307   b  Shaft door 
           308   a  Car door 
           308   b  Car door 
           313  Code band 
           314  Detector unit 
           317  Light barrier detector 
           401  Elevator apparatus 
           407  Shaft door 
           408  Car door 
           410  Gap opening 
           413  Code band 
           414  Optical sensor system 
           417  Light barrier detector 
           507  Car door 
           508  Shaft door 
           511  Recess 
           512  Recess 
           513  Code band 
           514  Sensor 
           607  Car door 
           608  Shaft door 
           610  Gap opening 
           612  Recess 
           613  Code band 
           614  Optical sensor 
           707  Car door 
           708  Shaft door 
           710  Gap opening 
           711  Indentation 
           712  Indentation 
           713  Code band 
           714  Detector unit 
           807  Car door 
           808  Shaft door 
           811  Indentation 
           812  Recess 
           813  Code band 
           814  Optical sensor 
           901  Elevator apparatus 
           907  Car door 
           908  Shaft door 
           911  Recess 
           912  Recess 
           913  Code band 
           914  Detector unit 
         A View 
         L Direction to the left 
         R Direction to the right 
         S Light barrier signal 
         Z Intermediate space