Abstract:
A door locking system for a freight or passenger elevator or goods lift installation having vertically spaced landings served by a vertically movable car, the landings and car each being protected by associated horizontal slide doors, a mechanical interlock device at each landing that prevents a landing door from opening without the presence of the car in registration with the landing, a door lock on the car for normally preventing the car door from opening when the car is out of registration with any landing, the interlock device being arranged to mechanically enable the door lock to release the car door to open when the car is in registration with a landing.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to doors for elevators, in particular, locking mechanism to prevent unintended opening of such doors. 
     PRIOR ART 
     As used hereinafter, the term “freight elevator” or “elevator” for short, will be understood to also apply to passenger elevators, goods lifts and other systems of similar function whether or not commonly described by these terms. Operators, passengers, and goods on an elevator are protected by a door carried on the elevator car while they and others are also protected by a separate door closing the elevator shaft at each landing. It is desirable, for such protection, that both the car door and landing doors be locked closed when the car is displaced away from a landing either vertically or horizontally. Various systems and devices have been proposed and/or produced to assure the locking of elevator car doors and landing doors. There has remained a need for a simple, reliable door locking system for freight elevator cars and landing doors including those with power door operators. 
     SUMMARY OF THE INVENTION 
     The invention provides, for freight elevators and the like, an integrated locking system for both elevator car and landing doors. More specifically, the locking system comprises a set of elements, essentially all mechanical, that serve to maintain a door of the car and the doors of the landings the car serves closed when the car is out of registration either vertically or horizontally with a landing. The system is arranged with lock control elements on the car and at the landings. These car and landing elements are ordinarily in mutual alignment and are conditioned for lock release only when the car is in the correct position at a landing. A driven one of the elements on the car is displaced automatically when a car door operator is energized. The driven element, with the condition that the car is properly vertically and horizontally positioned at a landing, is capable of unlocking both the associated landing door and the car door. The driven element, activated by the door operator, engages an element fixed on the landing door lock release and, in turn, this landing door release element displaces a car door lock release element. The various elements are arranged so that the landing door lock release element cannot be engaged by the driven element nor is it interposed between the driven element and the car door release element when the car is not registered with the landing. This condition of disconnection or disabling of the driven element ensures that the landing and car doors remain locked. 
     The disclosed door locking device is applied to horizontally sliding doors. The locking and unlocking elements for the most part rely on pivotal motion and thereby avoid erratic movement frequently encountered with translation or straight-line action induced by friction sticking at flat contacting or guiding surfaces of the locking elements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a fragmentary schematic perspective view of a freight elevator car on which a door locking device of the invention is employed; 
         FIG. 2  is an elevational view of the locking device taken from an outside front view of the top area of the freight elevator car with the car shown at a location below that of registration with a landing; 
         FIG. 2   a  is a plan view of the locking device of  FIG. 2 ; 
         FIG. 3  is an elevational view of a right-hand part of the locking device for a right-hand horizontally sliding door panel, the right-hand orientation being taken from the reference of a person standing in the elevator car, the left hand part of the locking device being essentially a mirror image; 
         FIG. 3   a  is a plan view of the device of  FIG. 3 ; 
         FIG. 4  is a view similar to  FIG. 3  but with the elevator car in registration with the landing and, specifically, showing a landing door locking part of the device in a release position; 
         FIG. 4   a  is a plan view of the device as positioned in  FIG. 4 ; 
         FIG. 5  is a view similar to  FIG. 3 , but showing positions of the locking device where a fault has occurred and the device continues to lock the associated door panel; and 
         FIG. 5   a  is a plan view of the device as positioned in  FIG. 5 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the figures and, in particular,  FIG. 1 , an elevator car  10  suitable for carrying freight or goods is shown. The car  10  moves vertically in a shaft to serve multiple landings spaced vertically from one another as is customary. Passage between the shaft and the car  10  is controlled by a landing or entrance door schematically illustrated at  11  and representative of a door at each landing. The landing door  11  is of the center-opening, horizontal sliding type such that one-half of the door slides to the right and one-half to the left. While not illustrated in detail, the right and left portions of the door  11  can each be comprised of multiple panels that are synchronized in their horizontal sliding movement as is known in the industry. The elevator car  10  is supplied with a similar center-opening, horizontal sliding door  12  having a right side  13  and left side  14  when viewed from the interior of the car  10 . 
     The invention provides a mechanical locking system for the car door  12  and each landing door  11  that in regular duty prevents these doors from being opened when the car  10  is not aligned or registered with a landing. The locking system disclosed herein will be seen to be “mechanical” such that it is conditioned to release the car door and a particular landing door by the physical presence of the car  10  at a proper position in registration with the landing. 
     At each landing  11 , the door locking system includes a door interlock assembly  16  arranged to releasably lock its respective landing door closed. The interlock assembly  16  is duplicated in right and left-hand versions, i.e. mirrored respectively, for the right and left-hand portions of the entrance door  11 . Each interlock assembly  16  includes a bell crank type structure  17  that pivots about a center  18  fixed on a respective left or right portion of the door  11 . The crank  17  includes a generally horizontal arm  19  with a depending hook  21  adapted to latch onto a bracket  22  fixed to the respective landing. A generally vertical arm  23  of the bell crank  17  extends upwardly from the horizontal arm  19  and pivot center  18 . The arm  23  carries two cam rollers  26 ,  27  one spaced above the other and both spaced above a third cam roller  28  located with its axis concentric with the pivot center  18 . 
     The right and left sides  13 ,  14  of the car door  12 , like the entrance door  11 , can have multiple panels that are synchronized in their horizontal sliding movement for opening and closing. The door locking system includes a locking device  31  associated with each car door side  13 ,  14 . The device  31  associated with the right and left door panels are symmetrical, i.e. mirrored. The locking device  31  has a pair of spaced opposed vertical bars, one bar  32  is “driven” and one bar  33  is a “lock bar”. Each bar  32 ,  33  is part of a respective four bar linkage generally designated by the numerals  34 ,  35  that ensures it remains vertical while being capable of moving a limited distance towards, with, or away from the other bar in a vertical plane common to the other bar. 
       FIGS. 3-5  illustrate a right-hand locking device  31  with the orientation referenced from within the elevator car  10 . The driven bar  32  is pivotally supported on a pair of bell crank levers  36  forming parts of the four bar linkage  34 . The driven bar  32  is connected to arms of the bell crank levers  36  with pin joints  38 . The bell crank levers  36  are pivotally supported on respective cantilevered pins  39  projecting from a bracket or plate  41 . The plate  41  is fixed to the respective door panel  13 . Other arms of the bell crank levers  36  pivotally support a connecting link  47 , the remaining element of the four bar linkage  34 , on pins  48 . The bell crank levers  36  and link  47  support the driven bar  32  in a vertical orientation and for limited, generally translatory horizontal motion. 
     The lock bar  33  is supported on the bracket or plate  41  in a manner similar to that of the driven bar  32 . The lock bar  33  is assembled on pins  51  carried on levers  52 ,  53 . The levers  52 ,  53  pivot on pins  54 , fixed on the bracket  41 . Pins  56  on the levers  52 ,  53  support a bar  57  that serves as a counterweight and connecting link. The lock bar  33 , levers  52 ,  53  and counterweight bar  57  work as the four bar linkage  35  and support the lock bar for limited generally horizontal translatory motion. The counterweight bar  57  resiliently biases the lock bar  33  horizontally towards the driven bar  32 . 
     Integral with the upper lever  52  is a generally horizontal arm  58  with an upstanding lock or hook  59  adjacent its distal end. The counterweight  57  serves to resiliently bias this hook  59  upwardly to the position illustrated in  FIG. 3  where it locks onto a bracket  61  fixed to the elevator car  10 . When the hook  59  is engaged with the bracket  61 , the associated elevator car door panel forming the right side  13  of the car door is prevented from opening. As shown in the various figures, a similar arrangement is provided for the panel on the left side  14  of the elevator car door  12 . 
     The car door panels are power operated by an electric motor  66  ( FIG. 1 ). Suitable electrical controls, under proper conditions, energize the motor  66  in one rotary direction to open the door panels and in the opposite rotary direction to close the door panels. The motor  66  driving through a gear box  67  and toothed pulley  68  is connected to the door panels with a high torque or high force toothed belt  69 . An upper strand or reach of the belt  69  is fixed to the right door panel  13  and the lower reach of the belt is fixed to the left door panel  14 . More specifically, the belt  69  is anchored by brackets  71  to the driven bar  32  of the locking device  31  at both the right and left sides  13 ,  14  of the car door  12 . 
     The following is an explanation of the automatic operation of the lock devices  16 ,  31 .  FIGS. 3   a ,  4   a  and  5   a  show that the right door panel cam rollers  26 ,  27  of the interlock assembly  16  are installed in a vertical plane that is common to these rollers and, normally, to the driven and lock bars  32 ,  33 , the latter elements forming lock control bars of the car door locking device  31 . The same is true for the left hand door panel, rollers  26 ,  27  and driven and lock bars  32 ,  33 . The car door locking devices  31  travel vertically with the car and when a car door panel is horizontally opened or closed, the locking device or assembly as well as the adjacent companion landing door panel and interlock assembly  16  travels horizontally with the car door. From  FIGS. 3-5 , it will be seen that when the motor  66  opens a car door panel through forces transmitted by the belt  69  to the associated driven bar  32  of the locking device  31 , the driven bar will simultaneously open the companion landing door panel by engagement with the cam roller  28 , recognizing that the latter cam roller is fixed relative to its associated landing door panel. 
     The landing and car door locks  16  and  31  are not readily accessible to a person in the car  10  and are normally intended to be released automatically, if the car is properly registered with a landing, by operation of the car door operator or motor  66 . Assuming the car  10  is properly located at a landing as depicted in  FIGS. 4 and 4   a , the door operating motor  66  is energized to open the car door and the landing door. Initial movement of the belt  69  to open the door panels  13 ,  14  moves the driven bars  32  in a generally horizontal direction by swinging them on their respective levers  36 . With the car  10  registered with a landing  11 , the cam rollers  26 - 28  are interposed between the associated driven and lock bars  32 ,  33 . Consequently, motion of the driven bar  32  is transmitted to the lock bar  33  through the rollers  26 - 28 . More specifically, the bell crank  17  of the interlock assembly or landing door lock  16  is rotated by contact of the driven bar  32  with the upper roller  26 . Pivotal movement of the bell crank arm  17  causes the middle roller to move the lock bar  33  of the car door locking device  31  generally horizontally by swinging on the levers  52 ,  53 , overcoming the bias force of the counterweight  57 . Swinging the lever  52  causes the hook  59  to be lowered, thereby releasing its lock on the fixed bracket  61 . Further motion of the belt  69  and driven bar  32  draws the door towards its open position by force applied through the bracket  71 . Simultaneously, each landing door panel is opened by force applied by the respective car door driven bar  32  to the lower roller  28 , which is fixed relative to the respective landing door panel. 
     The landing door lock hook  21  is raised to release its grip on the fixed bracket  22  by engagement of the upper roller  26  with the driven bar  32 . This engagement can be initiated when the car moves into the zone of the respective landing and an upper or lower camming edge  77  or  78  of the driven bar  32  contacts the roller  26 . Unlatching of the landing door panel may be completed as the driven bar  32  is moved in the door opening direction and the roller  26  further pivots the bell crank  17 . 
     With reference to  FIG. 4   a , it will be understood that with the lower roller  28  engaged by the driven bar  32  or the lock bar  33 , the landing door panels are automatically opened and closed by the motor  66  in unison with the car door panels  13 ,  14 . When the landing and car door panels are moved by the motor  66  to the closed position, the weight of the interlock arm  19  causes the landing door hook to relatch and the counterweight  57  causes the car door hook  21  to latch or relock. 
     From the foregoing, it will be understood that, assuming a car  10  is properly aligned at a landing, the initial movement of the car door operating motor  66  serves to unlock the car door panels  13 ,  14  and the corresponding landing door panels  11 . The initial motion of the motor  66  in a sense is “lost motion” with respect to the car and landing doors since only the driven bar and lock bar  32 ,  33  move in this stage. After the lock bar  33  is moved a sufficient distance to lower the lock hook  59 , the motor  66  moves the door panels toward their open positions. 
       FIGS. 3 ,  3   a ,  5  and  5   a  illustrate conditions where the car  10  is out of registration, e.g. below, a landing  11  and, consequently, the interlock cam rollers  26   28  of the landing door lock or interlock assembly  16 , are out of the space between the driven and lock bars  32 ,  33 . In this condition, the driven bar  32  cannot pivot the landing door lock bell crank  17  to unlock its hook  21  nor can it influence the car door lock bar  33  to release its lock hook  59 .  FIG. 5  illustrates a condition where the driven bar  32  has been moved to its unlocking position but is rendered ineffective to displace the lock bar  33  because of the absence of the cam rollers  26 ,  27  in the space between these bars. Note with reference to  FIGS. 3   a ,  4   a  and  5   a , the same ineffectiveness of the driven bar  32  to unlock both the landing and car door locks obtains where the elevator car is horizontally displaced from a landing so that the cam rollers  26 - 28  do not extend into the space between the driven and lock bars  32 ,  33  even where the car is vertically registered with a landing. 
     In the event of electrical power failure, malfunction of the door operating motor  66  or a broken belt, the car door locking device  31  and landing door lock  16 , will automatically open, if the car  10  is properly registered with the landing  11 , by force of a spring  81 . The spring  81  operates to pivot a lever  82  carrying a cam roller  83  bearing against the driven bar  32  to move the driven bar bell crank  17  with associated cam rollers  26 - 28  and the lock bar  33  to their respective door unlocking positions. 
     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.