Abstract:
Control systems and methods for operating the doors of an elevator where the control logic is distributed in local car and landing door controllers that communicate wirelessly with one another to eliminate door control signal wiring in the hoistway thereby simplifying installation and diagnostics and affording door motor control that is individualized for each door.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to elevator door operation and, in particular, to decentralized control for elevator doors. 
       PRIOR ART 
       [0002]    Traditionally, power operated freight elevator doors have been controlled remotely from controls located in a machine room where automatic controls for the elevator car itself were located. Signals for indicating the status of the doors, i.e. open, closed, locked, and malfunctioned were transmitted in dedicated wires running between the machine room and the floors served by the elevator and to the elevator car. Traditional discreet signal wire arrangements are expensive to install because of the amount of labor involved, including time frequently devoted to locating and correcting connection faults and errors as well as the cost of materials including wire, conduit, and accessories. U.S. Patent Publication US-2008-0091278-A1 illustrates improvements over traditional control wiring in elevator installations by employing serial communication to greatly reduce the number of wires required to control the elevator doors along a hoistway. 
         [0003]    At a particular site, the doors at different floors can vary in size and mass. These variations are not readily accounted for where it is desired to operate them with individual acceleration and speed profiles for smooth operation over an extended service life. 
       SUMMARY OF THE INVENTION 
       [0004]    The invention provides systems and methods of their operation for improvements in automatic control of elevator doors, particularly freight elevator doors. In a disclosed preferred embodiment of the invention, the control is decentralized by providing a separate door controller at each landing as well as on the elevator car. Consequently, the door control takes no space in the machine room. The landing door controllers monitor conditions at the respective doors and communicate the monitored conditions wirelessly to each other and the car door controller. Further, in the disclosed embodiment, the landing door conditions, including the landing door user push button operating commands, are passed wirelessly between a landing door controller and the car door controller enabling the car door controller to relay door condition data with wire in the travel cable to the elevator control. Similarly, the car door controller can wirelessly instruct a landing door controller with opening and closing signals. 
         [0005]    In the disclosed preferred embodiment, conditions at each landing door, including the identity of the floor, the presence of a stopped car indicated by a zone switch signal, and an emergency unlocking signal, are entered as a batch of data or “token” for wireless transmission to an adjacent landing and then succeeding landings. The token is passed wirelessly, i.e. by radio transmission, sequentially from one landing to the next adjacent landing up the hoistway and then down. When the token encounters the landing at which the car is stopped, the respective landing door controller wirelessly signals the car door controller of the landing door conditions at the landings through which the token passed and at its landing including its door position and door control push button signals. The car door controller, in turn, can relay certain of this information to the elevator controller by wire in the travel cable. 
         [0006]    The disclosed systems and methods afford many benefits to the door installer, building owner/operator, and service personnel. Hoistway door control wires and the expense to install and troubleshoot them are eliminated. The door controllers, with plug and play attributes are interchangeable for use at any landing and on the car. The door controllers are each capable of self-learning the size of the door to which it is assigned and utilize closed loop variable voltage, variable frequency (VVVF) electronic drive of the associated door operating motors for custom acceleration and deceleration profiles for the door and its smooth trouble-free operation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a schematic elevational view of a hoistway in which the invention is used; 
           [0008]      FIG. 2  is a schematic elevational view, from the car side, of a typical landing door control system; 
           [0009]      FIG. 3  is a schematic elevational view of a car door control system; 
           [0010]      FIG. 4  is a schematic view of a door controller; 
           [0011]      FIG. 4A  is a fragmentary enlarged view of the output relays of the controller; 
           [0012]      FIG. 5  is a fragmentary enlarged view of input connections of the controller for landing door service; 
           [0013]      FIG. 6  is a fragmentary enlarged view of the input connections of the controller for car door service; 
           [0014]      FIG. 7  is a fragmentary enlarged view of the controller showing connections to door motors at a landing; and 
           [0015]      FIG. 8  is a fragmentary enlarged view of the controller showing connections to a car door motor and a retiring cam motor. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0016]    Referring to the drawings and, in particular,  FIG. 1 , the invention is applied to a freight elevator installation  10  having an elevator car  11  operating in a hoistway  12  serving a plurality of landings  13  sometimes referred to as floors or halls. A travel cable  14 , as is customary, connects electrical devices on the car to an elevator controller  16  in a machine room  17 . 
         [0017]    At each landing  13 , as depicted in  FIG. 2 , a vertical bi-parting door  21  is power operated by a pair of motors  22 , preferably of conventional three phase design. A single motor can be used to operate a landing door where desired but may require a more complex door suspension. The motors  22  are powered through a door controller  23  and operate vertical bi-parting panels  24  of the door  21  through chains  26  in a known manner. A rotary encoder  27  monitors displacement of a chain  26  and therefore corresponding movement of the door panels  24  producing electrical pulses corresponding to increments of door movement. The encoder  27  is electrically connected to the controller  23  through wiring  28 . An emergency unlocking device (EUD)  29 , known in the art, for manually releasing a door lock  31  communicates a signal to the controller  23  through wiring  32 . A zone switch or sensor  33 , also known in the art, indicates through wiring  34  to the controller  23  the presence or absence of the car  11  stopped at the respective landing  13 . As known in the art, the zone switch  33  located at a landing  13  is operated by a retiring cam, disclosed below, carried on the car  11 . The zone switch  33  is operated when the door lock  31  is unlocked. The landing door system shown in  FIG. 2  is duplicated at each landing  13  served by the elevator car  11 , although the size (height) of the doors as well as their mass, can vary at a given installation from landing to landing. 
         [0018]    Referring to  FIG. 3 , a car door  40 , often referred to as a gate, opens and closes vertically on rails  41  that are part of the car  11 . Opening and closing movement of the car door  40  is produced by a car door motor  42 , preferably a conventional three phase electrical unit. The motor  42 , receiving electrical power from a door controller  23 , lifts and lowers the car door  40  with a chain  43  as is customary. A rotary encoder  44  connected to the controller  23  through wiring  46  signals the movement of the car door  40  by sensing movement of the chain  43 . Like the landing door encoder  27 , for a known increment of motion of the door  40 , the encoder  44  produces an electrical pulse thereby enabling the controller  23  to count pulses and know the speed and position of the door  40 . A retiring cam  51  known in the art pivots into or out of a position where it unlocks a landing door lock  31 . The retiring cam  51  is retracted or “retired” upon energization of an electric motor  52  preferably a three phase unit operated by the car controller  23  through wiring  53 ; in a customary manner, when the motor  52  is not electrically powered, the retiring cam  51  swings to an extended position where it unlocks the door lock  31  at the landing  13  hosting the car  11 . 
         [0019]    A reversing edge  56  of known construction operates as an electrical switch when it contacts an object in its path and electrically signals the car door controller  23  through wiring  57 . As will be described below, the car door controller  23  communicates with the elevator controller  16  through wiring in the travel cable  14 . 
         [0020]    The landing door and car door controllers  23  can be the same or substantially the same in construction and operation so that one can be substituted for the other with little or no modification to obtain the desired door operation.  FIG. 4  is a diagrammatic representation of the controller  23 . The controller  23  includes a motor power inverter circuit and a three phase drive circuit  61  that convert regular utility power, for example 60 Hz single phase 208-240 VAC to three phase variable voltage variable frequency (VVVF) power in a known manner. The controller  23  also includes a power supply  62  for the electronics and other components within the controller. Still further, the controller  23  includes a main microprocessor  63  that performs door control logic, directs radio communication to the other controllers, responds to signal inputs, produces signal outputs and drives an interactive LCD screen display, discussed below. The controller  23 , further, includes a motor drive microprocessor  64  that operates the car or landing doors, reads by counting the encoder signals to learn and register the size of a door opening, and establish the door opening movement profile. Still further, the controller  23  includes an LCD display and user keyboard section  65  used for set-up and adjustment of its respective door(s) by the mechanic and for trouble shooting and display of parameter settings for operating the door motor(s). Typical parameters for a particular door controller include: 
         [0021]    door type—either car door or landing door; 
         [0022]    channel—a unique number for the line of doors, i.e. front or rear and/or the particular hoistway in which the controller is used; 
         [0023]    floor address—a unique address number for the landing opening to which the controller is assigned; 
         [0024]    various other parameters involving, for example, speed, acceleration, deceleration of the door(s) which the controller operates. 
         [0025]    It is expected that the controller  23  can be modified or simplified where desired such as by eliminating one or more features or by combining features such as using one microprocessor to serve the function of the main and motor drive microprocessors  63 ,  64 . For purposes herein the term controller circuitry means one or both of the microprocessors  63 ,  64  or their electronic equivalent or equivalents. 
         [0026]    The illustrated controller  23  has a bank of five signal input terminals. When the controller  23  is used to operate a landing door, the inputs are assigned to the following door condition signals with the hall (landing) buttons, EUDs and zone switches working as sensors for the controller (see  FIG. 5 ): 
         [0027]    HOB, a hall open button input driven by a push button switch located at the controller&#39;s landing used to indicate that a user desires to open the door; 
         [0028]    HCB, a hall closed button input driven by a push button switch located at the controller&#39;s landing used to indicate that a user desires to close the door; 
         [0029]    STOP, a door stop button input driven by a push button switch located at the controller&#39;s landing used to indicate that a user desires to stop the door; 
         [0030]    ZONE input for door zone, an input driven by the switch  33  located within the lock  31  of each landing door that makes up and tells the door controller that the elevator car is stopped at its assigned landing; 
         [0031]    EUD input (emergency unlocking device), an input driven by a switch located in an emergency access box or EUD  29  actuated by the elevator personnel or firefighter used to indicate to the controller that the controller&#39;s landing door has been accessed. 
         [0032]    When the controller  23  is used on the car  11  to operate the car door  40 , the inputs are assigned to the following signals from the elevator controller  16  (see  FIG. 6 ): 
         [0033]    OPEN input—a signal command from the elevator controller to open the doors; 
         [0034]    CLOSE input—a signal command from the elevator controller to close the doors; 
         [0035]    NUDGE input—a signal command from the elevator controller to close the car door slowly (nudging); 
         [0036]    FAST input—a command from the elevator controller (used for firemen) to close the doors fast; 
         [0037]    RETCAM—an input signal command from the elevator controller to lift the retiring cam  51  to lock the landing door which eventually allows the car to move. 
         [0038]    From the foregoing, it will be seen that the controller  23  when it is assigned to the car  11  receives commands only from the elevator controller  16 . 
         [0039]    In both landing door and car door control service, the door controller  23  receives signals from respective encoders  27 ,  44  at a group of input terminals  67 . In both service for the car or landing, the controller  23  determines the instantaneous and rest positions of its assigned door by the number of pulses transmitted from the associated encoder  44  or  27 , e.g. starting at zero when closed and counting backward when closing. In either landing door control or car door control, as shown in  FIGS. 7 and 8 , the same set of connections  68  are used to power the respective door motors  22 ,  42  and retiring cam motor  52 . 
         [0040]    The door controller  23 , referencing  FIG. 4 , has a bank of eight separate relay contact sets. When the controller  23  is serving as a car door controller, these relay outputs are available for communicating with the elevator controller  16  through wires in the travel cable  14 . Alternatively, the door conditions which term includes hall button conditions reflected in these several relay contacts can be communicated through a set of output terminals  71  by, for example, serial communication using the CAN Open Lift profile. As shown in  FIG. 4 , the following relay outputs are provided: 
         [0041]    DOOR CLOSED; 
         [0042]    DOOR OPEN; 
         [0043]    USER  1 —a selectable relay output defaulted to indicate that the door is ¾ open; 
         [0044]    USER  2 —a selectable relay output defaulted to indicate that the door is ¾ closed; 
         [0045]    HALL OPEN—relays a signal that the Hall Open Button (HOB) of the hall door is pressed; 
         [0046]    HALL CLOSE—relays a signal that the Hall Close Button (HCB) of the landing is pressed; 
         [0047]    DOOR STOP—relay output indicates that the doors have stopped unexpectedly or that the STOP button of the hall door is pressed; 
         [0048]    REVERSING EDGE—relay output notifies the elevator controller that the contact type safety edge (shown in  FIG. 3  at  56 ) on the car door  40  is activated by contacting an object in its path. 
         [0049]    The door controller  23 , additionally, includes a radio card  66  with RF transceiver circuitry and antenna enabling it to communicate by two-way radio signals, i.e. in a wireless manner, to the other nearby controllers. The main microprocessor of the door controller  23  directs the radio card to transmit the “token” data, by a suitable protocol using the IEEE 802.15.4 standard, to the next controller. 
         [0050]    The door controller main microprocessor is programmed to suspend operation of the doors when a safety issue arises such as a multi-zone condition where two door zone switches  33  are activated at one time (since the elevator car can only be located at one floor) or when the emergency unlocking device EUD at any floor is activated. A multi-zone condition will be detected when the token passing technique of the controllers reveals that two zone switches are activated. This is accomplished by the token identifying the landing at which a zone switch is activated and maintaining this information as it sweeps up and down through the controllers of the hoistway. Whenever two landing addresses are associated with a zone switch activation, the door controller circuitry is programmed to discontinue door operation until the source of the error is cured. Similarly, the controller circuitry is programmed to discontinue door operation when ever a EUD signal is received at any of the landings. Still further, the controller circuitry is programmed to limit token passing to only between the landing door controller with the activated zone switch  33  and the car door controller for the brief period the car door and/or a landing door are in motion so that a delay however small, that might be involved with the time for the token to circulate through the landing controllers is avoided. This will avoid delaying a signal such as when the reversing edge signal arises. 
         [0051]    In automatic freight elevator systems, the position and movement of the elevator car is determined by the elevator controller  16 . Assuming the car  11  has just arrived at a landing  13 , the elevator controller  16  tells the car controller  23  via a wire in the travel cable  14  to the RETCAM input to extend the retiring cam, which is done by removing power to the retiring cam motor  52  in the illustrated embodiment. The extended retiring cam  51  unlocks the landing door lock  31  at the host landing  13  and the zone switch  33 , operated with the lock, signals the landing door controller  23  via a wire to the ZONE input that the car has arrived and the door has been unlocked. The landing door controller circuitry enabled by the ZONE input signal permits two way communication with the car door controller and causes a wireless signal transmission to the car door controller by way of passing the token to the car door controller. Controller circuitry is programmed so that landing door controllers not enabled by the presence of a ZONE signal cannot communicate directly by wireless transmission to the car door controller or receive wireless signals from the car door controller. 
         [0052]    When a landing door controller has a ZONE input signal, its controller circuitry is programmed to add its landing door conditions to the token and to divert the supplemented token to the car door controller. The car door controller, under normal circumstances, has its controller circuitry programmed to return the token to the landing door controller for circulation up and down the hoistway. The supplemented token, in addition to the external signals existing at its inputs discussed above, signals the following landing door conditions: 
         [0053]    Door Open Position, driven by the encoder positioning system after the opening has been learned; 
         [0054]    Door Closed Position, driven by the encoder positioning system after the opening has been learned; 
         [0055]    Other Door Positions, also driven by the encoder used for sequencing of the hall door and car door in the open and close cycle; 
         [0056]    Door Stop, used to indicate that the door is jammed or otherwise unexpectedly stopped or blocked; 
         [0057]    Various other program related functions including: 
         [0058]    door ready indication, door active indication, address number, acknowledgements. 
         [0059]    The door controller circuitry is programmed to “learn” its respective opening by initially counting the pulses from its encoder  27  or  44  during initial opening movement until the door stops against travel limits on its rails. The pulse count is stored in the memory of the controller circuitry for use in subsequent regular opening and closing cycles. Acceleration and deceleration profiles, during selective portions of total door movement can be programmed in the controller to take full advantage of the door travel length for both opening and closing. 
         [0060]    The car door controller circuitry is programmed to initiate door opening when it receives a token from the landing door controller that the zone switch has been made and it has a door open command at the OPEN input from the elevator controller. The car door controller wirelessly signals the landing door controller to open its door  21 . In response to this signal, the landing door controller supplies three phase (variable voltage variable frequency VVVF) power to its associated door motors  22 . When the landing door controller determines that its door  21  is ⅔ open, by encoder pulse count, it wirelessly signals the car door controller; at this time the car door controller initiates opening of the car door by applying three phase (variable voltage variable frequency VVVF) power to its motor  42 . Note that at this time, a retiring cam relay  72  ( FIG. 8 ) has de-energized the retiring cam motor  52  and has connected the car door controller to the car door motor  42 . The landing door controller wirelessly signals the car door controller that the landing door is fully open, as determined by encoder pulse count. Thereafter, when the car door is fully open, the car door controller signals the same to the elevator controller  16  via the DOOR OPEN relay output. 
         [0061]    The elevator controller  16  initiates door closing movement with a travel cable wire signal to the car door controller CLOSE input. The car door controller begins door closing by powering the car door motor  42  in reverse; when the car door is ⅔ closed, the car door controller wirelessly signals the landing door controller to initiate landing door closing. When the landing door is fully closed, the landing door controller wirelessly signals the same to the car door controller. When both the car and landing doors have closed, the car door controller signals the elevator controller  16  via a travel cable line connected to the DOOR CLOSE relay output. 
         [0062]    A travel cable wire signal to the car door controller RETCAM input from the elevator controller  16  through operation of the relay  72  and through the motor drive power causes the retiring cam to retire or retract resulting in the landing door at the host landing being locked in preparation for departure of the car. 
         [0063]    The elevator system can continue operation under control of the elevator controller. If an unusual condition such as the presence of a multi-zone signal, an EUD signal or a DOOR STOP signal produced at the landing hosting the car occurs in the token, the car door controllers will suspend operation of the doors. 
         [0064]    While the foregoing disclosure describes a freight elevator installation, the invention is applicable to passenger elevator installations, particularly where it is difficult to mechanically couple the car door(s) with the landing door(s) such as in high speed systems where close tolerances are problematic. 
         [0065]    It should be evident that this disclosure is by way of example and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention is therefore not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited.