Patent Publication Number: US-2020277163-A1

Title: Controlling movement of an elevator car

Description:
FOREIGN PRIORITY 
     This application claims priority to European Patent Application No. 19160328.1, filed Mar. 1, 2019, and all the benefits accruing therefrom under 35 U.S.C. § 119, the contents of which in its entirety are herein incorporated by reference. 
     BACKGROUND 
     The invention relates to a method of controlling movement of an elevator car within a hoistway of an elevator system. The invention further relates to an elevator system comprising an elevator drive which is configured for employing such a method. 
     An elevator system comprises an elevator car moving along a hoistway extending between a plurality of landings, and an elevator drive configured for driving the elevator car. 
     The elevator system may comprise components arranged within the hoistway outside the elevator car, which need to be accessed for maintenance and/or repair. The elevator car may comprise at least one opening allowing a mechanic to access such components by reaching out of the elevator car. When the elevator car moves or starts to move while a mechanic is reaching out of the elevator car, there is a risk that parts of the human body of the mechanic are squeezed between the elevator car and the hoistway. 
     It therefore is desirable to prevent the elevator car from moving while a person is reaching out of an elevator car. 
     SUMMARY 
     According to an exemplary embodiment of the invention, an elevator car defining an interior space comprises at least one opening providing a passage between the interior space and an exterior of the elevator car allowing a person within the interior space to reach out of the interior space, and at least one sensor configured for detecting any object extending through the at least one opening. 
     The at least one sensor may be connected with an alarm device issuing an acoustical/audible and/or optical/visible alarm when an object extending through the at least one opening is detected. Alternatively or additionally, the at least one sensor may issue a signal to an elevator drive, in particular to a controller, of the elevator system for preventing any movement of the elevator car when an object extending through the at least one opening is detected. 
     The object detected by the sensor in particular may be a part of human body, such as a head, an arm and/or a foot, of a mechanic reaching out of the elevator car. 
     Exemplary embodiments of the invention further include an elevator system comprising a hoistway extending between a plurality of landings; at least one elevator car according to an exemplary embodiment of the invention, which is configured for moving along the hoistway between the plurality of landings; and an elevator drive configured for moving the elevator car along the hoistway. In such an elevator system, the at least one sensor of the elevator car may be connected with the elevator drive and configured for preventing any movement of the elevator car when an object extending through the at least one opening is detected. 
     Exemplary embodiments of the invention further include a method of moving an elevator car in such an elevator system. The method includes providing input to the elevator drive via an input device; moving the elevator car according to said input; and stopping and preventing any movement of the elevator car when the sensor detects an object, in particular a part of a human body, extending through the at least one opening. 
     Exemplary embodiments of the invention also include a method of moving an elevator car in such an elevator system, wherein the method includes providing input to the elevator drive via an input device; moving the elevator car according to said input; determining the current position of the elevator car; and stopping and preventing any movement of the elevator, when the sensor detects an object, in particular a part of a human body, extending through the at least one opening, and the determined position of the elevator car is within a predetermined distance from an end of the hoistway and/or the elevator car is moving towards said end of the hoistway reducing the distance between the elevator car and said end of the hoistway. 
     Exemplary embodiments of the invention further include a method of maintaining and/or repairing an elevator system according to an exemplary embodiment of the invention, wherein the method includes employing the method according to an exemplary embodiment of the invention for moving the at least one elevator car to a predetermined position within the hoistway, stopping the at least one elevator car at said predetermined position, and accessing a component of the elevator system outside the at least one elevator car by reaching through the at least one opening of the elevator car. 
     Exemplary embodiments of the invention allow for safe operation, maintenance and repair of an elevator system, in particular including accessing components of the elevator system within the hoistway, even when a person, in particular a mechanic, is reaching out of the elevator car into the hoistway. 
     Exemplary embodiments of the invention allow reducing the clearance between the elevator car and components arranged within the hoistway requested by the safety code (EN81-20). According to exemplary embodiments of the invention, the mechanic will be obliged to stay inside the interior space of the elevator car when the elevator car is moving. This avoids all risk of the mechanic being sheared or crushed between the elevator car and components arranged within the hoistway. 
     A number of optional features are set out in the following. These features may be realized in particular embodiments, alone or in combination with any of the other features, unless specified otherwise. 
     The at least one sensor may include at least one light emitter and at least one light detector, in particular a laser and a laser detector, constituting a light barrier for detecting an object extending through the opening by interrupting the light barrier. 
     The at least one sensor may include an ultrasound emitter and a corresponding ultrasound receiver, or a radar wave emitter and a corresponding radar wave receiver for detecting an object extending through the opening due to ultrasound or radar waves reflected by said object. 
     The at least one sensor may include an optical camera for detecting an object extending through the opening in at least one picture taken by the camera. 
     For providing safe and convenient access through the at least one opening, the elevator car may comprise a platform allowing a person standing on the platform to reach trough the at least one opening. The platform may be movable between a storage position, in which it does not interfere with passengers within the elevator car, and a working position, in which it provides access to the at least one opening. 
     Depending on the position of the components, which are to be accessed, within the hoistway, an opening may be formed within the top (ceiling), bottom (floor) and/or within at least one sidewall of the elevator car. 
     In order to allow a mechanic to move the elevator car to a desired position within the hoistway, an elevator system according to an exemplary embodiment of the invention may comprise an input device provided within or at the elevator car, the input device being configured for receiving and transmitting manual inputs to the elevator drive for controlling the movement of the elevator car. 
    
    
     
       DRAWING DESCRIPTION 
       In the following, an exemplary embodiment of the invention is described in more detail with reference to the enclosed figures. 
         FIG. 1  schematically depicts an elevator system comprising an elevator car configured for moving along a hoistway. 
         FIGS. 2 and 3  depict perspective views of an elevator car with a platform arranged in a working position. 
         FIGS. 4 and 5  depict perspective views of an elevator car comprising a platform arranged in a working position and a sensor according to an exemplary embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  schematically depicts an elevator system  2 . 
     The elevator system  2  includes an elevator car  60  movably arranged within a hoistway  4  extending between a plurality of landings  10 . The elevator car  60  in particular is movable in a longitudinal (vertical) direction along a plurality of car guide members  14 , such as guide rails, extending along the vertical direction of the hoistway  4 . Only one of said car guide members  14  is depicted in  FIG. 1 . 
     Although only one elevator car  60  is shown in  FIG. 1 , the skilled person understands that exemplary embodiments of the invention may include elevator systems  2  including a plurality of elevator cars  60  moving in one or more hoistways  4 . 
     The elevator car  60  comprises a top (ceiling)  62 , a bottom (floor)  64  and a plurality of sidewalls  65  extending between the top  62  and the bottom  64  of the elevator car  60  defining an interior space  61  of the elevator car  60 . 
     The elevator car  60  is movably suspended by means of a tension member  3 . The tension member  3 , for example a rope or belt, is connected to an elevator drive  5 , which is configured for driving the tension member  3  in order to move the elevator car  60  along the height of the hoistway  4  between the plurality of landings  10 , which are located on different floors. 
     The exemplary embodiment shown in  FIG. 1  uses a 1:1 roping for suspending the elevator car  60 . The skilled person, however, easily understands that the type of the roping is not essential for the invention and that different kinds of roping, e.g. a 2:1 roping or a 4:1 roping may be used as well. 
     The tension member  3  may be a rope, e.g. a steel wire rope, or a belt. The tension member  3  may be uncoated or may have a coating, e.g. in the form of a polymer jacket. In a particular embodiment, the tension member  3  may be a belt comprising a plurality of polymer coated steel cords (not shown). The elevator system  2  may have a traction drive including a traction sheave for driving the tension member  3 . In an alternative configuration, which is not shown in the figures, the elevator system  2  may be an elevator system  2  without a tension member  3 . 
     The elevator system  2  also may comprise e.g. a hydraulic drive or a linear drive. The elevator system  2  may have a machine room (not shown) or it may be a machine room-less elevator system  2 . 
     The elevator system  2  further includes a counterweight  19  attached to the tension member  3  and configured for moving concurrently and in opposite direction with respect to the elevator car  60  along at least one counterweight guide member  15 . The skilled person will understand that the invention may be applied also to elevator systems  2  which do not comprise a counterweight  19 . 
     Each landing  10  is provided with a landing door  11 , and the elevator car  60  is provided with a corresponding elevator car door  12  for allowing passengers to transfer between a landing  10  and the interior of the elevator car  60  when the elevator car  60  is positioned at the respective landing  10 . 
     The elevator drive  5  includes an elevator controller  6  which is configured for controlling the elevator drive  5  for moving the elevator car  60  along the hoistway  4  between the different landings  10 . 
     Input to the elevator drive  5 , in particular to the controller  6 , may be provided via landing control panels  7   a,  which are provided on each landing  10  close to the landing doors  11 , and/or via an elevator car control panel  7   b,  which is provided inside the elevator car  60 . 
     The landing control panels  7   a  and the elevator car control panel  7   b  may be connected with the elevator drive  5  by means of electric wires, which are not shown in  FIG. 1 , in particular by an electric bus, or by means of wireless data connections. 
     The elevator car  60  may be equipped with at least one position reference system  20 , which is configured for detecting and/or determining the position of the elevator car  60  within the hoistway  4 . 
     The position reference system  20  may be an absolute position reference system  20 , including a position detector  22  configured for interacting with a coded tape  24  extending along the length of the hoistway  4 . Alternatively or additionally, the position reference system  20  may comprise a position detector  22  which is configured for determining the current position of the elevator car  60  within the hoistway  4  by detecting and integrating velocities and/or accelerations of the elevator car  60 . 
       FIGS. 2 to 5  depict perspective views of an elevator car  60  according to an exemplary embodiment of the invention during maintenance and/or repair procedures. 
     For accessing a component  76  of the elevator system  2  located within the hoistway  4  outside the elevator car  60 , a mechanic  70  within the interior space  61  of the elevator car has opened an opening  66  provided at the top  62  of the elevator car  60  allowing him to reach through the top  62  of the elevator car  60  for accessing the component  76 . The mechanic  70  may use at least one tool  73  when working on said component  76 . 
     In the exemplary embodiment depicted in  FIGS. 2 to 5 , the opening  66  extends basically completely over the top  62  of the elevator car  60 . In alternative embodiments, which are not explicitly depicted in the figures, the opening  66  may extend only over a portion of the top  62  of the elevator car  60  and/or the elevator car  60  may comprise two or more openings  66  provided at different positions at the top  62  of the elevator car  60 . 
     Similar openings (not shown) may be formed within the bottom  64  and/or within at least one sidewall  65  of the elevator car  60 , respectively. 
     The elevator car  60  may comprise a movable platform  68 , which is movable between a storage position (not shown), e.g. at the top  62  or at the bottom  64  of the interior space  61 , and a working position, in which it is depicted in  FIGS. 2 to 5 . When the platform  68  is arranged in the working position, a mechanic  70  may step onto the platform  68  for reaching through an opening  66  in the upper part of the elevator car  60 . 
     The platform  68  may be mounted to the elevator car  60  by at least one scissor mechanism  69  extending between the platform  68  and the top  62  of the elevator car  60 , as it is exemplarily depicted in  FIGS. 2 to 5 . A ladder  72  may be provided for allowing the mechanic  70  to climb conveniently onto the platform  68  when it is arranged in the working position in some distance above the bottom  64  of the elevator car  60 . 
     When the mechanic  70  is reaching through the opening  66 , at least some parts of his body are located within the hoistway  4  outside the interior space  61  of the elevator car  60 . 
     Thus, in case the elevator car  60  moves while the mechanic  70  is reaching through the opening  66 , there is some risk that parts  71  of the mechanic&#39;s body are squeezed between the elevator car  60  and the top, walls or bottom of the hoistway  4 . 
     It therefore is desirable to prevent any movement of the elevator car  60  while the mechanic  70  is reaching through an opening  66  of the elevator car  60  into the hoistway  4 . 
     According to an exemplary embodiment of the invention, the elevator car  2  is equipped with at least one sensor  82  (see  FIGS. 4 and 5 ), which is configured for monitoring an opening  66  of the elevator car  60  and for detecting any object  75 , in particular any tools  73  used by the mechanic  70  or parts  71  of a human body, extending through said opening  66 . 
     In the embodiment depicted in  FIGS. 4 and 5  a plurality of sensors  82  are provided next to each other establishing a virtual safety curtain  80  extending across the opening  66 . For clarity of the illustration, not all sensors  82  are provided with reference signs in  FIGS. 4 and 5 . 
     The at least one sensor  82  is connected with the elevator drive  5 , in particular the controller  6 . The elevator drive  5  is configured for stopping and/or preventing any movement of the elevator car  60  when the at least one sensor  82  detects any object  75 , in particular a tool  73  or a part  71  of a human body, extending through the opening  66 . 
     The at least one sensor  82  may be connected with the elevator drive  5  by means of electrical wires (not shown), including a bus system, such as a CAN bus, or by a wireless data connection. 
     The at least one sensor  82  may be implemented creating a light barrier, in particular a light barrier including at least one laser light source, extending over the whole opening  66 . Alternatively, the sensor  82  may constitute a plurality of light barriers, wherein each of the light barriers monitors a section of the opening  66 . 
     Instead of creating a light barrier, the at least one sensor  82  may employ ultrasonic or radar waves for detecting any objects  75  extending though the opening  66 , or it may comprise least one optical camera, which is configured for monitoring the opening  66  and detecting any objects  75  extending though the opening  66 . Combination of different techniques are possible as well. 
     In an elevator system  2  according to an exemplary embodiment of the invention, the elevator car  60  is allowed to move only when all tools  73  and parts  71  of a human body, in particular of a mechanic  70  being present within the elevator car  60 , are completely located within the interior space  61  of the elevator car  60  (see  FIGS. 4 and 5 ), and in particular when no object  75  extends though the opening  66  of the elevator car  60 . 
     An input device  74 , in particular a manual service control device, may be provided within the elevator car  60 . The input device  74  may be configured for allowing the mechanic  70  being present on the platform  68  to manually control the movement of the elevator car  60 , in particular for moving the elevator car  60  to a position within the hoistway  4  which allows convenient access to a desired component  76  of the elevator system  2 . 
     As an additional safety measure, the input device  74  may be positioned and configured so that the mechanic  70  is able to move the elevator car  60  by operating the input device  74  only when his body is completely within the interior space  61  of the elevator car  60 . 
     Such a safety measure, however, might be circumvented by two mechanics  70  cooperating with each other, in particular by a first mechanic  70  reaching out of the opening  66  and a second mechanic  70  operating the input device  74 . 
     In an elevator system  2  according to an exemplary embodiment of the invention, even such a cooperation of at least two mechanics  70  does not result in an unsafe situation, as any movement of the elevator car  60  is prevented when an object  75 , in particular a tool  73  or a part  71  of a human body extends though the opening  66 , as it has been described before. 
     Instead of, or in addition to, stopping and preventing any movement of the elevator car  60  when an object  75  extending through the opening  66  is detected, the elevator car  60  may be equipped with an alarm device  78  which is configured for issuing an acoustic and/or optical alarm signal in case an object  75  extending through the opening  66  is detected. 
     In a further configuration, the elevator drive  5  may be configured to allow movement of the elevator car  60  under certain circumstances despite an object  75  extending through the opening is detected. 
     For example, in case an object  75  extending through an opening  66  formed at the top  62  of the elevator car  60  is detected, the elevator drive  5  may allow the elevator car  60  to move downwards, as in case of a downward motion of the elevator car  60 , there is no risk that an object  75  is squeezed between the top  62  of the elevator car  60  and the upper end  41  of the hoistway  4 . 
     The elevator car  60  even may be allowed to move upwards even if an object  75  extending through an opening  66  formed at the top  62  of the elevator car  60  is detected, as long as a distance D 1  (see  FIG. 1 ) between the top  62  of the elevator car  60  and the upper end  41  of the hoistway  4  is larger than a predetermined distance providing a sufficiently large safety space between the top  62  of the elevator car  60  and the upper end  41  of the hoistway  4 . 
     Similarly, the elevator car  60  may be allowed to move upwards, in case an object  75  is detected as extending though an opening  66  formed within the bottom  64  of the elevator car  60 . 
     The elevator car  60  even may be allowed to move downwards even if an object  75  extending through an opening  66  formed within the bottom  64  of the elevator car  60  is detected, as long as a distance D 2  (see  FIG. 1 ) between the bottom  64  of the elevator car  60  and the lower end  42  of the hoistway  4  is larger than a predetermined distance providing a sufficiently large safety space between the bottom  64  of the elevator car  60  and the lower end  42  of the hoistway  4 . 
     Optionally, the maximum allowable speed of the elevator car  60  may be reduced when the elevator car  60  is allowed to move despite an object  75  extending out of the elevator car  60  into the hoistway  4  is detected. 
     While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adopt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention shall not be limited to the particular embodiment disclosed, but that the invention includes all embodiments falling within the scope of the dependent claims. 
     REFERENCES 
     
         
           2  elevator system 
           3  tension member 
           4  hoistway 
           5  elevator drive 
           6  elevator controller 
           7   a  landing control panel 
           7   b  elevator car control panel 
           10  landing 
           11  landing door 
           12  elevator car door 
           14  car guide member 
           15  counterweight guide member 
           19  counterweight 
           20  position reference system 
           22  position detector 
           24  coded tape 
           41  upper end of the hoistway 
           42  lower end of the hoistway 
           60  elevator car 
           61  interior space 
           62  top of the elevator car 
           64  bottom of the elevator car 
           65  sidewall 
           66  opening 
           68  platform 
           69  scissor mechanism 
           70  mechanic 
           71  part of a human body 
           72  ladder 
           73  tool 
           74  input device 
           75  object 
           76  component of the elevator system 
           78  alarm device 
           80  safety curtain 
           82  sensor 
         D 1  distance between the top of the elevator car and the upper end of the hoistway 
         D 2  distance between the bottom of the elevator car and the lower end of the hoistway