Patent Publication Number: US-6220396-B1

Title: Door restrictor apparatus for elevators

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to door interlock systems used in elevators. In particular, the invention concerns a door restrictor apparatus for an elevator door apparatus that prevents the elevator doors from opening when the elevator cab is between landings and not aligned with the hatchway doors of the system. 
     2. Description of the Related Art 
     In conventional elevators, an elevator car typically includes a motor to open and close the car door or doors. When the car is stopped at a landing, a clutch mechanism on the car door engages rollers on the hatchway door or doors so that the hatchway door opens and closes in unison with the car door. 
     One of the safety devices commonly provided on modern passenger elevators is a mechanism to prevent the car doors from opening when the car is not within a certain distance of the landing. This feature is desirable in the case of a car that has become stuck between floors, because it prevents passengers from prying open the doors in an attempt to exit the car, which could result in injury. Such devices also prevent the door(s) from opening in the event that the door motor, due to a malfunction, were to attempt to open the doors when the car is not at a landing. 
     U.S. Pat. No. 4,313,525, to McDonald, discloses a car door safety interlock system. In that system, a power operated sliding door of an elevator car is provided with a mechanical safety interlock which permits the car door to be moved more than a critical distance from its closed position only when the car is in a landing zone. A pivoted interlock hook on the car door has a normal position in which it engages an interlock lug on the car frame when the door moves the critical distance from closed position. A movable element on the car door is driven to move the hook to a clearance position relative to the interlock lug. Drive of the movable element occurs when it contacts an inter-engaging member on the hatch door as the car door first starts to move from closed position in a landing zone. 
     It is an object of the present invention to provide an improved apparatus for preventing an elevator car door from opening when the car is not within a predetermined distance of a landing. 
     SUMMARY OF THE INVENTION 
     The present invention provides a novel design of a door restrictor apparatus for locking and preventing a sliding door on an elevator car from unauthorized opening when the car is not at a landing area. In accordance with the present invention, a locking lug is mounted on the elevator car. An actuating mechanism having an actuating surface that moves toward and away from a surface on the car door is disposed on the surface of the car door. A pivotable hook, having an axis of rotation perpendicular to the direction of the door movement is also mounted on the door. The hook has a beak end that alternatively passes by or engages the locking lug depending upon the rotational position of the hook. A crank and push rod assembly disposed on the door is connected to the actuating mechanism and to the hook and couples the movement and position of the actuating surface to the rotation and position of the hook and vice-versa. The restrictor apparatus also includes a means for biasing the restrictor to urge the actuating surface to move away from the door and to urge the hook to rotate in a first direction (e.g. clockwise). In a preferred embodiment, the means for biasing is at least one leaf spring mounted to the actuating mechanism. 
     The restrictor apparatus of the invention has three positions: (i) a closed position; (ii) an unlocked position; and (iii) a locked position. In the closed position, the elevator car doors are closed, the hook is oriented at a first position and the actuating surface is oriented at a corresponding first position relative to the door surface. When the elevator doors are closed the beak end of the hook engages a fixed member mounted on the car and the hook is thereby rotated to the first position and the restrictor apparatus is thus placed in the closed position. In a preferred embodiment, the fixed member is a hook roller mounted on the car and having an axis of rotation that is parallel to the axis of rotation of the hook. 
     As the sliding door(s) begins to open, the beak end moves off the fixed member. Because of the bias in the apparatus, the hook begins to rotate and the actuating surface begins to move away from the surface of the door. At this point, the restrictor apparatus will move into the unlocked or locked position depending on whether the car is at a landing or is between landings. In the unlocked position, when the door opens while the car is at a landing, the hook will rotate and stop at a second position where the beak will pass by the lug as the door opens and wherein the actuating surface is at a corresponding second position. In the locked position, when the door opens while the car is not at a landing, the hook will rotate and stop at a third position where the beak will engage the lug and wherein the actuating surface is at a corresponding third position. 
     The crank and push rod assembly has a crank body that rotates about an axis. A first arm extends from the crank body in a direction generally perpendicular to the axis of rotation. A second arm extends from the crank body also in a direction generally perpendicular to the axis of rotation. A slide bushing is seated on the first arm and has a cylindrical bore. The slide bushing is capable of rotating about and sliding along the first arm. The slide bushing also has an elongated slot with a length dimension parallel to its cylindrical axis and has a width dimension perpendicular to the length dimension that is shorter then the length dimension. 
     In one embodiment, the present invention is employed in an elevator system having an elevator shaft, a plurality of landings, and hatchway doors at each landing. Each hatchway door has one or more hatchway rollers for engaging a clutch that is mounted on the outside of the car door. The clutch and hatchway rollers, when engaged, cause the hatchway door to open in unison with the car door. As discussed below, the hatchway door rollers also can be used to engage the actuating surface of the actuating mechanism. 
     In operation of this embodiment, the present invention functions as follows. When the car door is closed, the hook is at a first position and the actuating surface is at a corresponding first position. The apparatus is calibrated such that when the restrictor is in the closed position the actuating surface at the corresponding first position will not hit any protrusions, such as the hatchway rollers when the car is traveling between floors. When the car is at landing area (i.e., within a predetermined distance of a landing) and the door begins to move from the closed position to the open position, the hook begins to rotate in the first direction but stops rotating at the second position. The hook, which is coupled with the actuating surface, stops rotating because the actuating surface contacts the hatchway door rollers. When the hook stops in the second position the restrictor apparatus is in the unlocked position. When the restrictor apparatus is unlocked, the hook passes by the lug and the elevator door may freely slide open. If, however, the car is not at a landing area as the car door moves from the closed position toward the open position, the hook rotates in the first direction to the third position, at which the beak end will engage and lock against the lug and prevent the door from opening farther. When the car is not at a landing, the hook will not stop at the second position because the actuating surface is free to move away from the surface of the door and is not stopped by the hatchway door rollers. 
     For a better understanding of the invention, reference is made to the following detailed description of a preferred embodiment, taken in conjunction with the drawings accompanying the application. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     FIG. 1 is a front view of an elevator car door, looking from outside of the car, showing the elevator doors and restrictor apparatus according to the invention in the closed position. 
     FIG. 2 is a perspective view of the door restrictor apparatus of the invention in the closed position as the elevator car is approaching a landing but still above the hatchway door zone. FIG. 2 shows a pair of conventional rollers that are disposed on the hatchway door (not shown) at the landing. 
     FIG. 3 is a perspective view of the door restrictor apparatus in the invention, with a car above a landing and consequently outside the hatch door zone. FIG. 3 also shows the car doors partially opened and the door restrictor apparatus engaged in the locked position. 
     FIG. 4 is an enlarged view of the upper portion of the apparatus shown in FIG.  3 . 
     FIG. 5 is a perspective view of the door restrictor apparatus, with the door in the closed position and the elevator car at a landing and inside the hatch door zone. FIG. 5 shows a pair of conventional rollers on the hatch door (not shown) disposed above but not in contact with the actuating mechanism of the door restrictor apparatus. 
     FIG. 6 is a perspective view of the door restrictor apparatus in the unlocked position with the car at a landing and the cars doors partially opened. FIG. 6 shows a pair of conventional rollers on the hatch door (not shown) disposed above and pressingly contacting mechanism of the door restrictor. 
     FIG. 7 is an enlarged perspective view of the upper portion of the door restrictor apparatus of FIG. 6 showing the car doors partially opened and the apparatus in the unlocked position. 
     FIG. 8 shows an enlarged perspective view of an actuating finger member denoted by elements  50  and  51  depicted in the figures. 
     FIG. 9 is an enlarged perspective view of crank element  38  depicted in the figures. 
     FIG. 10 is an enlarged perspective view of slide bushing element  52  depicted in the figures. 
     FIG. 11 is a front view of a crank and push rod assembly. 
     FIG. 12 is a front perspective view of the crank and push rod assembly. 
     FIG. 13 is a rear perspective view of the crank and push rod assembly. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the figures, wherein like reference numerals designate like parts, FIG. 1 shows an elevator door arrangement and the restrictor apparatus of the invention. In FIG. 1, the doors and restrictor apparatus are shown in their closed position. The doors  10  and  10   a  are suspended from an overhead rail  12 , which is part of the car body, by hangers  14  containing wheels  16 , so that the doors  10 ,  10   a  can move in a longitudinal direction between open and closed positions. The doors  10 ,  10   a  are coupled to one another, for example by a continuous cable, for simultaneous movement in opposite directions. 
     The doors are automatically opened and closed using a motor and drive mechanism (not shown), and a processor which controls the drive motor responsive to its own programming and sensors in the doorway which detect obstructions. Such arrangements are well known in the art. 
     The door  10  includes a clutch mechanism comprised of vanes  20  and  22 . These vanes  20  and  22  are designed to engage a pair of hatchway door rollers  24 ,  25  (shown in FIGS. 2,  3 ,  5 , and  6 ) when the car is at a landing area (i.e., within a certain distance of the landing, which is determined by the size of the components in the system). Such clutch mechanisms are well known, and thus need not be described further herein. Any suitable clutch mechanism may be used with the present invention. 
     The present invention is directed to an interlocking door restrictor apparatus for locking and preventing the elevator car doors from opening when the car is not at a landing. Referring to FIG. 1, a protrusion, such as roller  26 , is mounted on the top of the car body with a bracket  28  fixed to the top rail  12 . The axis of the rotation of the roller  26  is oriented to be perpendicular to the direction of the door movement. The bracket  28  also contains a lug  27  for engaging a beak end  30   a  of a hook member  30 . The hook member  30  is pivotally mounted on the door with a pivot bolt  31  and has an axis of rotation perpendicular to direction of motion of the door  10 . The hook member  30  also has a second end  30   b  for pivotally engaging an upper end of a push rod  42 , which is part of a crank and push rod assembly  100  (outlined with dashed lines in FIG. 1, and discussed in greater detail below). 
     Referring now to FIG. 2, the door restrictor apparatus also includes an actuating mechanism  32  positioned between the clutch vanes  20  and  22  and mounted on the ends of two leaf springs  34 . The opposite ends of the springs  34  are secured to the car door  10 , for example with screws  36 . In this manner, the actuating mechanism  32  is cantilevered relative to the car door  10  and can pivot about a vertical axis against the force of the springs  34 . The actuating mechanism  32  includes an actuating surface  35  that is vertically disposed between a pair of opposed ramp portions  37   a  and  37   b , which are angled toward the car door  10 . The force of springs  34  generally tends to urge the actuating surface  35  and associated ramp portions  37   a  and  37   b  to move away from the surface of the door  10 . 
     The actuating mechanism  32  is connected to the crank and push rod assembly  101  at plate  51 . As stated above, the leaf springs  34  bias the actuating mechanism  32  to move away from the car door  10 . The crank and push rod assembly  100  couples the movement of the actuating mechanism  32  to the rotation of the hook  30 . Through the coupling provided by the crank and push rod assembly  100 , the bias that urges the actuating surface  35  to move away from the door  10   a  is translated into a rotational bias that urges the hook member  30  to rotate in a clockwise direction. Any crank and push rod assembly capable of coupling the movement of the actuating surface to the rotational movement of the hook  30  will be suitable. 
     A preferred crank and push rod assembly  100  is outlined by dashed lines in FIG. 1, and is shown a greater detail in FIGS. 8-13. Referring to FIG. 11, the crank and push rod assembly is composed of a crank body  38 . The crank body  38  is mounted to the car door  10  with a bracket  40  and is rotatable about its cylindrical axis, which is parallel to a plane formed by the surface of the car door. (See dashed lines and arrows in FIGS.  12  and  13 ). 
     As shown in FIGS. 9 and 11, the crank body  38  has a first arm  38   a  that extends perpendicular from the crank body  38 . The first arm  38   a  is generally cylindrically shaped, and extends from the crank body  38  in a manner such that its cylindrical axis is perpendicular to the cylindrical axis of the crank. The crank further comprises a cylindrically shaped slide bushing  52  (see FIGS. 10 and 11) having a cylindrical axis concentric with the cylindrical axis of the first arm  38   a . The slide bushing  52  is free to slide toward and away from the crank  38  along the first arm  38   a  and is free to rotate about its cylindrical axis. As is depicted in FIG. 10, the slide bushing  52  has an elongated slot  53 . 
     A plate  51  is attached at one end to the actuating mechanism  32  (See FIG. 13) and cantilevers towards and away from the surface of door  10   a  in unison with the actuating mechanism  32 . The plate  51  has an actuator finger  50  (See FIG. 8) that extends through the elongate slot  53  of slide bushing  52  forming a generally right angle with the slide bushing when viewed from the front (See FIG.  11 ). When the actuator mechanism  32  moves toward and away from the car door  10  about its vertical axis of rotation, the actuating finger  50  cause the crank  38  to rotate about its cylindrical axis. 
     As shown in FIGS. 9 and 13, the crank  38  has a second arm  38   b , generally perpendicular to the first arm  38   a . The lower end of the push rod  42  is attached to the second arm  38   b  by a ball joint assembly  39 . (See FIG.  13 ). An upper end of the push rod  42  is attached to hook member  30  (see FIG.  1 ), thus coupling the hook member  30  to the crank and push rod assembly  100  so that when the crank  38  rotates, the hook  30  also rotates and vice-versa. The push rod  42  of the crank and push rod assembly  100 , may be angled to the left of vertical by up to 45 degrees. 
     The crank and push rod assembly  100  operates in conjunction with hook  30  and actuating mechanism  32  as follows. Referring to FIG. 1, if the hook member  30  is rotated counterclockwise with a sufficient force to overcome the bias created by the leaf springs  34 , then the push rod  42  moves generally upward. Referring now to FIG. 12, the upward movement of push rod  42  causes the crank assembly  38  to rotate and consequently causes the first arm  38   a , the plate  51 , and the actuating mechanism  32  to move toward the car door  10  against the force of the leaf springs  34 . When the hook member  30  rotates clockwise, the push rod  42  moves in a generally downward position. This rotates the crank body  38  in an opposite direction and consequently causes the first arm  38   a , plate  51 , and the actuating mechanism  32  to move away from the car door with the force of the leaf springs  34 . 
     The restrictor appartus of the invention has three positions of operation: (i) a closed position when the elevator car door is closed; (ii) an unlocked position when the car is at a landing and the door is permitted to open; and (iii) a locked position when the car is not at a landing and the door is not permitted to open. 
     In operation, referring to FIGS. 1,  2  and  5 , when the car door and the restrictor apparatus are in the closed position, the beak  30   a  of the hook member  30  engages the center of the hook roller  26 , which rotates the hook member  30  in a counterclockwise direction to a first position and consequently moves the actuating mechanism  32  toward the surface of door  10   a  to a corresponding first position. When the restrictor apparatus is in the closed position and the actuating mechanism is in the corresponding first position, the actuating surface  35  and ramps  37   a  and  37   b  will not come into contact with hatchway door rollers  24  and  25  as the elevator car moves from floor to floor (See FIGS.  2  and  5 ). While the preferred embodiment uses a hook roller  26  to maintain the restrictor apparatus in the closed position, it is envisioned that a fixed member may be used in place of a hook roller  26 . 
     Referring to FIGS. 3-7, as the door  10  opens, the beak  30   a  rolls off the hook roller  26  and the bias in the system created by leaf springs  34  causes the hook member  30  to begin rotating clockwise. As the hook member  30  rotates clockwise, the push rod  42  moves generally downward, rotating the crank  38  and consequently allowing the actuating mechanism  32  to move away from the car door with the force of leaf spring  34 . The restrictor apparatus will then move into an unlocked position or locked position, depending on whether the car is at a landing. 
     In the unlocked position (depicted in FIGS.  6  and  7 ), when the car is at a landing area and the doors begin to open, as the beak  30   a  rolls off the hook roller  26 , the actuating surface  35  will contact the hatchway rollers  24 ,  25  and thus limit the distance that the leaf spring  34  will bias the actuating mechanism  32  away from the car door  10 . While in one embodiment the actuating surface contacts hatchway rollers, it is envisioned that other protruding members fixed to the hatchway door or any stationary surface within an elevator system may be used to engage the actuating surface  35 . The limitation in the movement of actuating surface  35  limits the clockwise rotation of the hook member  30  causing the hook member  30  to stop at a second position when the actuating surface  35  reaches a corresponding second position (i.e., the position of actuating surface  35  when it hits the hatchway rollers  24 ,  25 ). The push rod  42  is adjusted so that when the actuating surface  35  contacts the hatchway rollers  24 ,  25  and the hook stops at the second position, the beak  30   a  will pass through the lug  27  as the door  10  is opened. 
     In the locked position (depicted in FIGS. 3 and 4) when the car is not at a landing area, as the beak  30   a  rolls off the hook roller  26 , the leaf spring  34  biases the actuating mechanism  32  away from the car door  10  and, because the actuating mechanism  32  is in a position where it will not contact hatchway rollers  24 ,  25 , the actuating mechanism  32  is free to move away from the car door. Thus, the hook member  30  continues to rotate clockwise to a third position where the beak  30   a  engages the lug, and thus prevents the car door from opening any farther. 
     In the preferred embodiment, when the elevator doors  10 ,  10   a  are closed, the push rod  42  is adjusted so that the distance between the actuating mechanism  32  and the hatchway rollers  24 ,  25  is about 0.25 inch and thus the actuating mechanism  32  does not contact the hatchway rollers  24 ,  25  as the car moves between floors. (See FIG.  5 ). However, when the car is at rest on a landing and an attempt to open the door is made, the actuating mechanism contacts the hatchway rollers  24 ,  25  before the hook member  30  rotates to a position where the beak  30   a  will engage the locking lug  27  and thus allows the door to open. (See FIGS.  6  and  7 ). 
     The foregoing represents a preferred embodiments of the invention. Variations and modifications will be apparent to persons skilled in the art, without departing from the inventive concepts disclosed herein. For example, while the invention has been described in a door system using center-opening doors, it is equally applicable to a single door or to telescoping door arrangements. Also, while it is convenient to utilize the conventional hatchway rollers to engage the actuating surface, if desired some other protruding member can be mounted on the hatchway doors and used for such purpose. Such alternative would provide greater freedom in the choice of where to locate the actuating mechanism of the interlock mechanism. Also, while the connecting rod is shown as being coupled to the hook member on the opposite end of the hook, the rod (or other suitable coupling member, such as a cable), could be coupled to the hook member on the same side of the pivot  31  as the hook itself In addition, while an example is given of a hook member which is positioned below the roller, the roller could be located above the roller, in which case the coupling mechanism between the actuating mechanism and the hook member would be arranged to move the hook upwardly when the actuating mechanism is pushed towards the car door. Finally, while the roller axis is shown as being horizontal, it is possible to orient such axis vertically, or at some angle between horizontal and vertical, provided that the hook member&#39;s pivot axis is parallel to the axis of the roller. All such modifications and variations are intended to be within the skill of the art, as defined in the following claims.