Patent Publication Number: US-8973714-B2

Title: Door engagement device for elevator

Description:
TECHNICAL FIELD 
     The present invention relates to a door engagement device for an elevator, which brings car doors and landing doors of an elevator into engagement with each other. 
     BACKGROUND ART 
     An engagement-mechanism driving device for a conventional door engagement device for an elevator includes a vane driving link having a center-fold structure, which freely turnably connects an arm mounted turnably to a fixed portion of a door device main body and an arm extending from a driving cam mounted turnably onto the door engagement device mounted to a car door so as to drive a car-side engagement mechanism. 
     In the case of the engagement-mechanism driving device described above, when the door engagement device moves in a horizontal direction as viewed from the front of the door through a car-door opening/closing operation, a linear distance between a fixed shaft provided to the door device main body and a turning shaft of the driving cam included in the door engagement device changes. As a result, a center-fold portion of the vane driving link moves upward or downward. 
     By the above-mentioned movement, the arm extending from the driving cam turns about the turning shaft of the driving cam. 
     When the driving cam turns, an engagement vane provided to the car-side engagement mechanism moves to a door-closing side or a door-opening side by the driving cam to perform a gripping/releasing operation of a landing-side engagement mechanism (for example, see Patent Literature 1). 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP 2006-103882 A (Pages 3 to 7, FIG. 1) 
       
    
     SUMMARY OF INVENTION 
     Technical Problems 
     In the conventional door engagement device for the elevator, the vane driving link which connects the fixed portion of the door device main body and the driving cam of the engagement mechanism is required to drive the driving cam for operating the engagement vane of the engagement mechanism. Therefore, the above-mentioned door engagement device has the following problems. 
     A. A space in which the vane driving link moves is required inside the door device main body. 
     B. A length or shape of the vane driving link is required to be changed if a door width or a mounting height of the door engagement device differs. 
     C. The vane driving link is large. Therefore, mounting thereof requires efforts, and cost becomes high. 
     The present invention has been made to solve the problems described above, and has an object to provide a door engagement device for an elevator, for driving an engagement-mechanism driving device, with a reduced space at low cost. 
     Solution to Problems 
     According to the present invention, there is provided a door engagement device for an elevator, provided between a car door guided on a hanger rail of a door device main body to perform an opening/closing operation and a landing door for performing an opening/closing operation for a landing doorway, for opening/closing the landing door in association with the opening/closing operation of the car door, the door engagement device for an elevator including: 
     a car-side engagement mechanism for gripping a landing-side engagement mechanism provided to the landing door when the car door is opened/closed; and 
     an engagement-mechanism driving device for driving the car-side engagement mechanism, 
     in which the engagement-mechanism driving device includes:
         a lever support shaft provided to the car door;   a lever main body provided turnably in a reciprocating manner between a start point and an end point about the lever support shaft;   turning guiding means for guiding turning of the lever main body turning about the lever support shaft; and   biasing-force applying/changing means for applying a turning preventing force for preventing the turning of the lever main body and changing a direction of a biasing force to a direction of an anti-turning preventing force to the lever main body by action of the turning guiding means with movement of the car door.       

     Further, according to the present invention, there is provided a door engagement device for an elevator, provided between a car door guided on a hanger rail of a door device main body to perform an opening/closing operation and a landing door for performing an opening/closing operation for a landing doorway, for opening/closing the landing door in association with the opening/closing operation of the car door, the door engagement device for an elevator including: 
     an engagement vane for gripping a landing-side engagement mechanism provided to the landing door when the car door is opened/closed; 
     a cam support shaft provided to the car door; 
     a driving cam provided freely turnably in a reciprocating manner between a start point and an end point about the cam support shaft to actuate the engagement vane in association with turning; 
     a moving member provided to the driving cam; 
     a fixed cam fixed to the door device main body, including a cam groove for guiding the moving member; and 
     biasing-force applying/changing means for applying a turning preventing force for preventing the turning of the driving cam and changing a direction of a biasing force to a direction of an anti-turning preventing force to the driving cam in middle of movement of the car door by the movement of the car door, 
     in which the biasing-force applying/changing means is configured to:
         apply, when the car door is opened, the turning preventing force to the driving cam having the moving member moved into the cam groove so as to apply a resistance force against door opening to the car door and apply the anti-turning preventing force to the driving cam to change a biasing direction of the driving cam as a result of turning of the driving cam about the cam support shaft with movement of the moving member along the cam groove of the fixed cam and movement of the cam support shaft; and   apply, when the car door is closed, the turning preventing force to the driving cam to apply a resistance force against door closing to the car door just at time at which the moving member moves into the cam groove and apply the anti-turning preventing force to the driving cam to change the biasing direction of the driving cam as a result of turning of the driving cam about the cam support shaft with the movement of the moving member along the cam groove of the fixed cam and the movement of the cam support shaft.       

     Advantageous Effects of Invention 
     According to the door engagement device for an elevator of the present invention, the biasing-force applying/changing means is configured to: apply, when the car door is opened, the turning preventing force to the lever main body by the action of the turning guiding means so as to apply the resistance force against door opening to the car door and apply the anti-turning preventing force to the lever main body to change the direction of the biasing force to the lever main body in the middle of the door-opening operation of the car door; and apply, when the car door is closed, the turning preventing force to the lever main body to apply the resistance force against door closing to the car door in the initial state by the action of the turning guiding means and apply the anti-turning preventing force to the lever main body to change the direction of the biasing force to the lever main body in the middle of the door-closing operation of the car door. Therefore, for the car door, a function of exerting the resistance force against door opening when the door starts opening and exerting the resistance force against door closing immediately before the closure of the door can be realized by the existing engagement-mechanism driving device without increasing the number of components. As a result, manufacturing cost can also be prevented from being increased. 
     Further, according to the door engagement device for an elevator of the present invention, the biasing-force applying/changing means is configured to: apply, when the car door is opened, the turning preventing force to the driving cam having the moving member moved into the cam groove so as to apply the resistance force against door opening to the car door and apply the anti-turning preventing force to the driving cam to change the direction of the biasing force to the driving cam; and apply, when the car door is closed, the turning preventing force to the driving cam to apply the resistance force against door closing to the car door just at time at which the moving member moves into the cam groove and apply the anti-turning preventing force to the driving cam to change the direction of the biasing force to the driving cam. Therefore, for the car door, the function of exerting the resistance force against door opening when the door starts opening and exerting the resistance force against door closing immediately before the closure of the door can be realized by the existing engagement-mechanism driving device without increasing the number of components. As a result, the manufacturing cost can also be prevented from being increased. 
     Further, the lever main body and the lever support shaft are eliminated to further reduce the cost. 
    
    
     
         FIG. 1  is a front view of a door device for an elevator with double doors as viewed from a landing-door side. 
         FIG. 2  is a perspective view illustrating the door device illustrated in  FIG. 1 . 
         FIG. 3  is a perspective view illustrating a door engagement device of the door device illustrated in  FIG. 1 . 
         FIG. 4  is a front view illustrating one mode of use (initial state with doors open) of the door engagement device for the elevator, illustrated in  FIG. 1 . 
         FIG. 5  is a front view illustrating another mode of use (vane-closed state) of the door engagement device  1  illustrated in  FIG. 1 . 
         FIG. 6  is a front view illustrating the principal part of the door engagement device according to Embodiment 2 of the present invention. 
         FIG. 7  is a front view illustrating the principal part of the door engagement device according to Embodiment 3 of the present invention. 
         FIG. 8  is a front view illustrating the door engagement device for the elevator according to Embodiment 4 in an initial state when the doors are opened. 
         FIG. 9  is a front view illustrating a vane-closed state of the door engagement device for the elevator, which is illustrated in  FIG. 8 . 
         FIG. 10  is a front view of the door engagement device for the elevator according to Embodiment 5 in an initial state when the doors are opened. 
         FIG. 11  is a front view illustrating another mode of use (vane-closed state) of the door engagement device for the elevator, which is illustrated in  FIG. 10 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinbelow, embodiments of the present invention are described with reference to the drawings. In the drawings, the same or corresponding members and parts are represented by the same reference symbols in the description. 
     Embodiment 1 
       FIG. 1  is a front view of a door device for an elevator with double doors as viewed from a landing-door side,  FIG. 2  is a perspective view illustrating the door device illustrated in  FIG. 1 ,  FIG. 3  is a perspective view illustrating a door engagement device  1  of the door device illustrated in  FIG. 1 ,  FIG. 4  is a front view illustrating one mode of use (initial state with doors open) of the door engagement device for the elevator, illustrated in  FIG. 1 , and  FIG. 5  is a front view illustrating another mode of use (vane-closed state) of the door engagement device  1  illustrated in  FIG. 1 . 
     The door device for the elevator includes a door device main body  4  for opening and closing car doors  5  and a door engagement device  1  provided between landing doors (not shown) for opening and closing a landing doorway and the car doors  5 , for allowing the landing doors to perform an opening/closing operation in association with an opening/closing operation of the car doors  5 . 
     The above-mentioned door device main body  4  includes a door driving motor  43 , a driving pulley  442  provided on a driven-side car door  52  side of the car doors  5  including a driving-side car door  51  and the driven-side car door  52 , a driving belt  44  provided between the driving pulley  442  and the door driving motor  43 , for transferring a driving force of the door driving motor  43  to the driving pulley  442 , an idler pulley  443  provided on the driving-side car door  51  side, and a belt  441  looped between the idler pulley  443  and the driving pulley  442 . 
     The door device main body  4  also includes a hanger rail  42  extending below the belt  441  in parallel to the belt  441  and a door hanger  41  moving along the hanger rail  42 . 
     The door hanger  41  includes a driving-side hanger plate  411  fixed onto an upper surface of the driving-side car door  51 , a driven-side hanger plate  412  fixed onto an upper surface of the driven-side car door  52 , hanger rollers  413  freely turnably provided to both upper corner portions of each of the driving-side hanger plate  411  and the driven-side hanger plate  412 , for rolling on the hanger rail  42 , a driving-side belt gripper  414  having a base end portion fixed to the driving-side hanger plate  411  and a distal end portion which grips a lower side of the endless belt  441 , and a driven-side belt gripper  415  having a base end portion fixed to the driven-side hanger plate  412  and a distal end portion which grips an upper side of the endless belt  441 . 
     The above-mentioned door-engagement device  1  includes a car-side engagement mechanism  2  provided on a base plate  23  fixed on a surface of the driving-side door  51  and an engagement-mechanism driving device  3  for driving the car-side engagement mechanism  2 . 
     The car-side engagement mechanism  2  includes an engagement vane  21  including a first vane  211  and a second vane  212  opposed to the first vane  211  in parallel thereto, a vane link  22  including an upper vane link  221  and a lower vane link  222 , which are connected to the first vane  211  and the second vane  212 , and a driving cam  24  provided on the base plate  23 , which has a cam groove  241  formed along an outer peripheral portion. The first vane  212  and the second vane  212  grip a landing-side engagement mechanism (not shown) provided to the landing door. 
     The above-mentioned engagement vane  21  includes vane support shafts  213  provided respectively to the first vane  211  and the second vane  212 , for freely turnably supporting the upper vane link  211  and the lower vane link  222 , respectively, and a cam follower  214  provided to the first vane  211  in a projecting manner, for moving along the cam groove  214  of the driving cam  24 . 
     The first vane  211  and the second vane  212  constitute, together with the upper vane link  221  and the lower vane link  222  which are opposed to each other in parallel, a link mechanism in a parallelogram. 
     Link support shafts  223  freely turnable with respect to the base plate  23 , are respectively provided to the upper vane link  221  and the lower vane link  222  at positions closer to the second vane  212  side. 
     The upper vane link  221  and the lower vane link  222  turn about the link support shafts  223 . The first vane  211  and the second vane  212  move vertically as well as horizontally in association with the turning. 
     The above-mentioned driving cam  24  having a fan-like shape includes a cam support shaft  242  provided freely turnably with respect to the base plate  23  and a connection-bar mount shaft  243  provided to a base end portion on the side opposite to the side where the cam groove  241  is provided through the cam support shaft  242 . 
     The cam groove  241  is formed so as to have a decreasing distance to the cam support shaft  242  in a counterclockwise direction and has an arc-like shape having the same radius from the middle. 
     The above-mentioned engagement-mechanism driving device  3  includes a fixed cam  33  fixed to a fixed portion  45  of the door device main body  4 , a lever  31  provided to the driving-side hanger plate  411 , a connection bar  36  to which the lever  31  and the connection-bar mount shaft  243  of the driving cam  24  are connected, a stopper  32  for stopping actuation of the lever  31 , and a lever retention spring  34  for applying a resistance force against door opening (door-closing retention force) and a resistance force against door closing (door-opening retention force) for the car doors  5 . 
     The above-mentioned lever  31  includes a mount plate  313  mounted to the driving-side hanger plate  411 , a fan-like lever main body  311  provided turnable onto the mount plate  311  by a lever support shaft  314 , a roller  312  corresponding to a moving member freely turnably provided to one corner portion of the lever main body  311 , and a connection-bar mount shaft  315  provided to the other corner portion of the lever main body  311 , to which a distal end portion of the connection bar  36  is connected. 
     The fixed cam  33  fixed to the door device main body  4 , which has a cam groove  331 , and the roller  312  corresponding to the moving member provided to the lever main body  311 , which moves along the cam groove  331 , constitute turning guiding means for guiding the turning of the lever main body  331 . 
     The fixed cam  33  and the roller  312  are an example. Therefore, as the turning guiding means for guiding the turning of the lever main body, for example, a roller rolling on an end surface of a plate cam may be used. 
     One end portion of the above-mentioned lever retention spring  34  is connected to a lever spring-fixed point  341  provided to the lever main body  311 , whereas the other end portion thereof is connected to a door spring-fixed point  342  provided to the mount plate  313 . 
     The lever retention spring  34  applies a force for turning the lever main body  311  in a counterclockwise direction about the lever support shaft  314  when the lever main body  311  is in an initial position corresponding to a state in which the car doors  5  are closed. The force acts as a force for preventing the doors from opening, that is, the resistance force against door opening when the car doors  5  start opening and acts as a force for preventing the doors from being closed, that is, the resistance force against door closing from the middle of the door-opening operation of the car doors  5 . 
     The lever spring-fixed point  341  provided to the lever main body  311 , the door spring-fixed point  342  provided to the car doors  5 , and the lever retention spring  34  which connects the lever spring-fixed point  341  and the door spring-fixed point  342  constitute biasing-force applying/changing means. The lever retention spring  34  is provided so that the lever spring-fixed point  341  is located on the opposite sides with respect to a straight line connecting the door spring-fixed point  342  and the lever support shaft  314  at a start point and an end point of movement of the lever main body  311 . 
     The connection-bar mount shaft  243  of the driving cam  24  and the connection-bar mount shaft  315  of the lever  31  are connected to each other by the connection bar  36 . 
     The cam groove  331  is formed on the above-mentioned fixed cam  33  at an angle θ (θ≧0°) with respect to a vertical direction so that each of horizontal angles α of angles formed by crossing a guide line indicated by a two-dot chain line A connecting the center of the lever support shaft  314  and the center of the roller  312  and a guide line indicated by a two-dot chain line B extending along parallel guide surfaces of the cam groove  331 , which are opposed to each other, becomes 90° or larger. The roller  312  provided to the lever main body  311  rolls along the cam groove  331 . 
     Next, an operation of the door device for the elevator, which has the above-mentioned configuration, is described. 
     First, a door-opening operation of the car doors  5  is described. 
     By the driving of the door driving motor  43 , the driving pulley  442  turns through an intermediation of the driving belt  44 . With the turning of the driving pulley  442 , the belt  441  moves. 
     With the movement of the belt  441 , the driving-side hanger plate  411  and the driving-side car door  51 , and the driven-side hanger plate  412  and the driven-side car door  52  start to move in a direction so as to be separated away from each other, specifically, each of the car doors  5  starts to move in a door-opening direction. 
     With the door opening of the car doors  5 , a horizontal direction between the lever support shaft  314  of the lever  31  and the fixed cam  33  is reduced for the driving-side car door  51 . Then, the roller  312  provided to the lever main body  311  moves up in the cam groove  331  so as to maintain a distance to the lever support shaft  314 . With the upward movement, the lever main body  311  turns in a clockwise direction against an elastic force of the lever retention spring  34  about the lever support shaft  314 . 
     By adjusting the inclination angle θ of the cam groove  331 , the relation between a distance of movement of the driving-side hanger plate  411  and the angle of turning of the lever main body  311  is adjusted. 
     Specifically, when the inclination angle θ is increased in the clockwise direction, the angle of turning of the lever main body  311  becomes large with respect to the amount of movement of the driving-side hanger plate  411 . When the angle θ is reduced, the angle of turning is reduced. 
     The resistance force against door opening also changes depending on the angle θ. When the angle θ is increased, the lever retention spring  34  is further extended to increase the resistance force against door opening. When the angle θ is reduced, the resistance force against door opening is reduced. 
     With the turning of the lever main body  311  in the clockwise direction, the connection-bar mount shaft  243  is pulled up through an intermediation of the connection bar  36  to turn the driving cam  24  about the cam support shaft  242  in the clockwise direction. 
     With the turning of the driving cam  24 , the cam follower  214  mounted to the first vane  211  rolls along the wall surfaces of the cam grooves  241 . As a result, the first vane  211  is forcibly moved in the door-opening direction. 
     With the driving of the first vane  211 , the second vane  212  moves in the door-closing direction because the second vane  212  constitutes the parallel link mechanism together with the first vane  211 , the upper vane link  221 , and the lower vane link  222 . As a result, a distance between the first vane  211  and the second vane  212  becomes smaller. 
     After the lever main body  311  turns to a predetermined position, the distance between the first vane  211  and the second vane  212  is constant in the further turning. 
     Specifically, after the driving-side hanger plate  411  moves by a preset distance, the first vane  211  is not further moved in the door-opening direction with the turning of the lever main body  311  because the cam groove  241  has the arc-like shape with the same radius with respect to the cam support shaft  242  from the middle thereof. Therefore, the first vane  211  and the second vane  212  are retained in a gripped state with the distance reduced by the set amount as compared with that in the initial state with the doors open. 
     The first vane  211  and the second vane  212  grip the landing-side engagement mechanism (not shown) provided to the landing door in the process of reduction of the distance. Thereafter, in association with the door opening of the car doors  5 , the landing doors (not shown) are also opened. 
     By the rolling of the cam follower  214  provided to the first vane  211  along the cam groove  241 , the first vane  211  moves in the door-opening direction. Therefore, a speed at which the first vane  211  and the second vane  212  come closer to each other, and the amount of movement of the driving-side hanger plate  411  until the first vane  211  and the second vane  212  are brought into the gripped state can be adjusted by the shape of the cam groove  241 . 
     When the driving-side hanger plate  411  further moves in the door-opening direction, the lever main body  311  further turns in the clockwise direction against the elastic force of the lever retention spring  34 . Moreover, the lever support shaft  314  moves in the door-opening direction. Therefore, the roller  312  is positioned on the vertical line of the lever support shaft  314  in the cam groove  331 , specifically, the roller  312  reaches the highest point in the cam groove  331 . 
     Thereafter, the roller  312  starts moving down in the cam groove  331  to roll to a notch portion  334  of the cam groove  331  to move out of the cam groove  331 . Thereafter, simultaneously with the separation of the roller  312  from the cam groove  331 , the lever main body  311  collides against the stopper  32  mounted to the mount plate  313  by the elastic force of the lever retention spring  34  so as to be stopped (see  FIG. 5 ). The position is a turning end position of the lever main body  311 . 
     The lever main body  311  and the driving cam  24  turn in association with the opening operation of the car doors  5  until the roller  312  separates away from the notch portion  334  of the cam groove  331 . 
     Thereafter, the door engagement device  1  moves in the door-opening direction in the state illustrated in  FIG. 5  until the amount of opening of the car doors  5  becomes equal to a predetermined amount of opening. 
     On the other hand, when the roller  312  moves out of the notch portion  334  of the cam groove  331 , the lever spring-fixed point  341  of the lever retention spring  34  moves to the side opposite to that in the initial state with respect to a two-dot chain line C connecting the lever support shaft  314  and the door spring-fixed point  342  mounted to the mount plate  313 . 
     Specifically, the turning direction of the lever main body  311  by the elastic force of the lever retention spring  34  changes from the counterclockwise direction to the clockwise direction to press the lever main body  311  against the stopper  32 . As a result, the roller  312  moves out of the cam groove  331 . At the same time, the lever main body  311  collides against the stopper  32  mounted to the mount plate  313  by the elastic force of the lever retention spring  34  so as to be stopped. 
     When the car doors  5  start opening, the lever retention spring  34  applies the force in a direction of turning the lever main body  311  in the counterclockwise direction so that the force acts as the force for preventing the turning of the lever main body  311 , that is, the resistance force against door opening. After the roller  312  moves out of the cam groove  331 , the force of the lever retention spring  34  acts as the force for retaining the lever main body  311  in the turning end position. 
     Next, a door-closing operation of the car doors  5  is described. 
     The operation of the door engagement device  1  during the door-closing operation of the car doors  5  is reverse to that during the above-mentioned door-opening operation of the car doors  5 . 
     In the door-closing operation, when the car doors  5  are closed, specifically, by the driving of the door driving motor  43 , the belt  411  moves in the direction opposite to the door-opening direction so that the driving-side hanger plate  411  and the driven-side hanger plate  412  move closer to each other. When the driving-side hanger plate  411  reaches a predetermined position, the roller  312  moves into the cam groove  331  of the fixed cam  33  through the notch portion  334 . 
     Thereafter, as the car doors  5  are closed, the roller  312  rolls upward along the cam groove  331  so as to maintain the distance to the lever support shaft  314  of the lever retention spring  34 . Moreover, the lever support shaft  314  moves in the door-closing direction. Therefore, the roller  312  moves down again after reaching the highest point at which the roller  312  has a vertical relation with the lever support shaft  314 . 
     By the movement of the roller  312 , the lever main body  311  turns in the direction opposite to that during the door-opening operation, that is, in the counterclockwise direction to turn the driving cam  24  about the cam support shaft  242  in the counterclockwise direction through an intermediation of the connection bar  36 . 
     The force of the lever retention spring  34  is applied in the direction in which the lever main body  311  is turned in the clockwise direction just at the time at which the roller  312  moves into the cam groove  331  and acts as a force for preventing the turning of the lever main body  311 , that is, the resistance force against door closing. 
     After the roller  312  moves into the cam groove  331  of the fixed cam  33 , the driving-side hanger plate  411  is closed to a predetermined position. Then, by the movement of the driving cam  24  guided by the cam groove  241  which moves in association with the movement of the roller  312 , the first vane  211  moves to the door-closing side through an intermediation of the cam follower  214 . Then, the first vane  211  and the second vane  212  start opening in a direction of moving away from each other. Thereafter, when the car doors  5  are fully closed, the door engagement device  1  returns to the initial state. 
     The movement of the first vane  211  and the second vane  212  away from each other releases the gripped state by the landing-side engagement mechanism. 
     According to the door engagement device  1  for the elevator according to this embodiment, when the car doors  5  are opened, the biasing-force applying/changing means applies the turning preventing force to the lever main body  311  having the roller  312  corresponding to the moving member moved into the cam groove  331  so as to apply the resistance force against door opening to the car doors  5  and applies an anti-turning preventing force to the lever main body  311  to change a direction of a biasing force to the lever main body  311 . Further, when the car doors  5  are closed, the biasing-force applying/changing means applies the turning preventing force to the lever main body  311  to apply the resistance force against door closing to the car doors  5  just at the time at which the roller  312  moves into the cam groove  331  and applies the anti-turning preventing force to the lever main body  311  to change the direction of the biasing force to the lever main body  311 . Therefore, the resistance force against door opening (door-closing retention force) acts on the car doors  5  when the doors start opening. Therefore, even if electric power to the door driving motor  43  is interrupted for some reason, the car doors  5  can be prevented from being opened. Moreover, the resistance force against door closing acts immediately before the doors are closed. In this manner, an impact noise between the driving-side car door  51  and the driven-side car door  52 , which is generated when the doors are closed, can be alleviated. 
     The biasing-force applying/changing means includes the lever spring-fixed point  341  provided to the lever main body  311 , the door spring-fixed point  342  provided to the car doors  5 , and the lever retention spring  34  connecting the lever spring-fixed point  341  and the door spring-fixed point  342 . The lever retention spring  34  is provided so that the lever spring-fixed point  341  is located on the opposite sides with respect to the straight line connecting the door-spring fixed point  342  and the lever support shaft  314  at the start point and the end point of movement of the lever main body  311 . Therefore, a function of exerting the resistance force against door opening when the doors start opening and exerting the resistance force against door closing immediately before the closure of the doors can be realized by the existing engagement-mechanism driving device without increasing the number of components. As a result, manufacturing cost can be prevented from being increased. 
     Further, according to the door engagement device  1  for the elevator according to this embodiment, the driving cam  24  is turned through an intermediation of the connection bar  36  with the turning of the lever main body  311 . With the turning, the cam follower  214  rolls inside the cam groove  241  to move the first vane  211  and the second vane  212  closer to each other or away from each other. Therefore, even if the vane driving link which connects the fixed portion  45  of the door device main body  4  and the driving cam  24  is eliminated, the first vane  211  and the second vane  212  can be driven to be opened/closed. 
     Further, even if the position at which the door engagement device  1  is mounted changes vertically, the change can be covered by changing a length of the connection bar  36 . In addition, even if the width of the car doors  5  changes, the first vane  211  and the second vane  212  can be driven with the same components. Therefore, the components other than the connection bar  36  can be commonly used. 
     Further, the roller  312  separates away from the cam groove  331  of the fixed cam  33  before the car doors  5  are fully opened. Thus, it is not necessary to form the fixed cam  33  over the entire range of movement of the driving-side car door  51 . As a result, the engagement-mechanism driving device  3  can be configured with a saved space. 
     Embodiment 2 
       FIG. 6  is a front view illustrating the door engagement device  1  according to Embodiment 2 of the present invention. 
     In the engagement-mechanism driving device  3  according to Embodiment 2, the lever  31  mounted to the door hanger  41  includes the mount plate  313 , the lever support shaft  314  provided to the mount plate  313 , the lever main body  311  having a triangular shape, mounted turnably to the lever support shaft  314 , and the roller  312  corresponding to the moving member mounted onto the lever main body  311 . 
     A resistance spring  35  corresponding to resistance force applying means including a torsion spring, for applying a force for preventing the turning when the lever main body  311  turns, is mounted to the fixed cam  33 . 
     The resistance spring  35  is provided in the vicinity of the cam groove  331  of the fixed cam  33 . One end portion of the resistance spring  35  is fixed onto the fixed cam  33  by a resistance spring fixing portion  332 , whereas the other end thereof is a free end portion which projects across the cam groove  331 . A portion to which the roller  312  is mounted is a contact portion  316  against which the free end portion of the resistance spring  35  abuts. 
     The contact portion  316  is located on the opposite sides with respect to a vertical line passing through the lever support shaft  314  at a start point and an end point of the turning of the lever main body  311  which turns about the lever support shaft  314 . 
     The remaining configuration is the same as that of Embodiment 1. 
     Next, an operation of the door engagement device  1  for the elevator according to Embodiment 2, which has the above-mentioned configuration, is described. 
     When the door hanger  41  moves in the door-opening direction to reduce a horizontal distance between the fixed cam  33  and the lever support shaft  314 , the roller  312  is guided by the cam groove  331  to be going to move upward so as to maintain a distance between the lever support shaft  314  and the roller  312 . 
     Then, the contact portion  316  of the roller  312  comes into contact with the free end portion of the resistance spring  35  to lift up the free end portion so that a force for returning back the roller  312  downward is exerted by the resistance spring  35 . The force acts as the resistance force against door opening. 
     In the case where the car doors  5  are closed, when the roller  312  moves into the cam groove  331  of the fixed cam  33  in the middle of the door-closing operation, the roller  312  is going to move upward along the cam groove  331 . At this time, the lever main body  311  is subjected to a force for pushing back the lever main body  311  downward by the resistance spring  35 . The force for pushing back downward acts as the resistance force against door closing. 
     According to the door engagement device  1  for the elevator according to this embodiment, the biasing-force applying/changing means includes the resistance spring  35  corresponding to the resistance force applying means provided to the fixed cam  33 , which applies the resistance force in a direction for preventing the movement of the roller  312  moving along the cam groove  331  of the fixed cam  33  when the car doors  5  are opened/closed. The contact portion  316  at which the resistance spring  35  abuts against the roller  312  is located on the opposite sides with respect to the vertical line passing through the lever support shaft  314  at the start point and the end point of the turning of the lever main body  311 . Therefore, the resistance force against door opening can be exerted on the car doors  5  when the doors start opening, whereas the resistance force against door closing can be exerted on the car doors  5  immediately before the doors are closed. Thus, the same effects as those of Embodiment 1 can be obtained. 
     Moreover, by adjusting the elastic force of the resistance spring  35 , the door-closing retention force and the resistance force against door closing can be easily adjusted. 
     Although the torsion spring is used as the resistance spring  35 , a compression spring or a leaf spring may be used instead. 
     Embodiment 3 
       FIG. 7  is a front view illustrating the door engagement device  1  according to Embodiment 3 of the present invention. 
     In this embodiment, a resistance weight  37  is used as the resistance force applying means in place of the resistance spring  35 . 
     In the case of the door engagement device described above, the resistance weight  37  is provided so as to be vertically movable along resistance weight guides  333  fixed to the fixed cam  33  to close a passage of the cam groove  331 . The resistance weight  37  applies a downward force to a contact portion  317 , which acts as a force for bringing back the upward movement of the roller  312  downward. 
     According to the door engagement device  1  of this embodiment, the biasing-force applying/changing means includes the resistance weight  37  corresponding to the resistance force applying means provided to the fixed cam  33 , which applies the resistance force in a direction for preventing the movement of the moving member  312  moving along the cam groove  331  of the fixed cam  33  when the car doors  5  are opened/closed. The contact portion  317  at which the resistance weight  37  abuts against the roller  312  is located on the opposite sides with respect to the vertical line passing through the lever support shaft  314  at the start point and the end point of the turning of the lever main body  311 . Therefore, the resistance force against door opening can be exerted on the car doors  5  when the doors start opening, whereas the resistance force against door closing can be exerted on the car doors  5  immediately before the doors are closed. Thus, the same effects as those of Embodiment 1 can be obtained. 
     Moreover, by adjusting the weight of the resistance weight  37 , the door-closing retention force and the resistance force against door closing can be easily adjusted. 
     Embodiment 4 
       FIG. 8  is a front view illustrating the door engagement device  1  for the elevator according to Embodiment 4 in an initial state when the doors are opened, and  FIG. 9  is a front view illustrating a vane-closed state of the door engagement device for the elevator, which is illustrated in  FIG. 8 . 
     In this embodiment, a driving cam  24 A also serves as the lever main body  311 , and therefore the connection bar  36  is not provided. 
     A roller  244  corresponding to a moving member is mounted to the driving cam  24 A so that the roller  244  rolls inside the cam groove  331  of the fixed cam  33 . 
     The remaining configuration is the same as that of Embodiment 1. 
     In this embodiment, when the car doors  5  move, the driving cam  24  is turned about a cam support shaft  242 A to drive the car-side engagement mechanism  2 . 
     Specifically, in Embodiment 1, the movement of the lever main body  311  is transferred to the driving cam  24  by the connection bar  36  to turn the driving cam  24 . However, the roller  244  is mounted to the driving cam  24 A to directly turn the driving cam  24 A. 
     The lever retention spring  34  is mounted so as to retain the driving cam  24 A instead of retaining the start point and the end point of the turning of the lever main body  311 , which is described in Embodiment 1. As a result, the elastic force of the lever retention spring  34  acts so that the driving cam  24 A is retained in the closed state of the engagement vane  21  or the open state of the engagement vane  21  and acts as the resistance force against door opening when the doors start opening and as the resistance force against door closing immediately before the doors are closed. 
     Next, an operation of the above-mentioned door engagement device  1  for the elevator according to Embodiment 4 is described. 
     When the car doors  5  start moving in the door-opening direction, a horizontal distance between the cam support shaft  242 A of the driving cam  24 A and the fixed cam  33  is reduced as in Embodiment 1. For maintaining the distance between the roller  244  and the cam support shaft  242 A, the roller  244  rolls upward inside the cam groove  331 . 
     When the car doors  5  are further opened, the roller  244  reaches the highest point inside the cam groove  331  and then starts moving downward. When the car doors  5  are opened to a predetermined position, the roller  244  moves out of the cam groove  331 . When the roller  244  moves out of the cam groove  331 , the driving cam  24 A abuts against the stopper  32  corresponding to the end surface of the upper vane link  221  to stop moving (see  FIG. 9 ). 
     Thereafter, the door engagement device  1  moves in the above-mentioned state until the door opening is completed. 
     By the movement of the roller  244  as described above, the driving cam  24 A turns in the clockwise direction about the cam support shaft  242 A. Then, the cam groove  241  formed on the driving cam  24 A also turns, and the cam follower  214  provided to the first vane  211  is guided by the cam groove  241  to drive the first vane  211  to the door-opening side. 
     The first vane  211  and the second vane  212  constitute the parallel link with the upper vane link  221  and the lower vane link  222 . Therefore, when the first vane  211  moves to the door-opening side, the second vane  212  moves to the door-closing side. As a result, the engagement vane  21  of the car-side engagement mechanism  2  is closed. 
     As in Embodiment 1, the movement performed when the car doors  5  are closed is reverse to that performed when the doors are opened. 
     Specifically, when the car doors  5  are closed to a predetermined position, the roller  244  provided to the driving cam  24 A moves into the cam groove  331  of the fixed cam  33  and moves upward inside the cam groove  331 . Thereafter, the roller  244  reaches the highest point to move downward and returns to the initial position in the door-closed state. 
     By the above-mentioned operation, the driving cam  24 A turns in the counterclockwise direction to open the engagement vane  21  of the car-side engagement mechanism  2  with the operation reverse to that performed when the doors are opened. 
     According to the door engagement device  1  for the elevator according to this embodiment, when the car doors  5  are opened, the biasing-force applying/changing means applies the turning preventing force to the driving cam  24 A having the roller  244  corresponding to the moving member moved into the cam groove  331  so as to apply the resistance force against door opening to the car doors  5 . With the movement of the roller  244  along the cam groove  331  of the fixed cam  33  and the movement of the cam support shaft  242 A, the driving cam  24 A turns about the cam support shaft  242 A to apply the anti-turning preventing force to the driving cam  24 A so as to change the biasing direction of the driving cam  24 A. When the car doors  5  are closed, the biasing-force applying/changing means applies the turning preventing force to the driving cam  24 A to apply the resistance force against door closing to the car doors  5  just at the time at which the roller  244  moves into the cam groove  331 . With the movement of the roller  244  along the cam groove  331  of the fixed cam  33  and the movement of the cam support shaft  242 A, the driving cam  24 A turns about the cam support shaft  242 A to apply the anti-turning preventing force to the driving cam  24 A so as to change the biasing direction of the driving cam  24 A. Therefore, the same effects as those of the door engagement device  1  for the elevator according to Embodiment 1 can be obtained. In addition, in comparison with the door engagement devices according to Embodiments 1 to 3, the lever main body  311  and the lever support shaft  314  are eliminated to simplify the configuration of the lever  31 . Thus, the door engagement device  1  can be provided at further lower cost. 
     Embodiment 5 
       FIG. 10  is a front view of the door engagement device  1  for the elevator according to Embodiment 5 in an initial state when the doors are opened, and  FIG. 11  is a front view illustrating another mode of use (vane-closed state) of the door engagement device for the elevator, which is illustrated in  FIG. 10 . 
     In this embodiment, instead of providing the lever retention spring  34 , a thickness of the driving cam  24 A on the door-opening direction side is increased so that a position G of center of gravity of the driving cam  24 A is located on the left with respect to a vertical line passing through the cam support shaft  242 A when the car-side engagement mechanism  2  is in an open state and located on the right when the car-side engagement mechanism  2  is in a closed state. 
     As described above, in this embodiment, the biasing-force applying/changing means is the driving cam  24 A having the position of center of gravity which is located on the opposite sides with respect to the vertical line passing through the cam support shaft  242 A at the start point and the end point of the turning of the driving cam  24 A. Therefore, in comparison with Embodiment 4, the lever retention spring  34  is not required. Accordingly, the door engagement device  1  can be provided at further lower cost. 
     The position G of center of gravity of the driving cam  24 A may be decentered so that the position G of center of gravity of the driving cam  24 A is located on the left with respect to the vertical line passing through the cam support shaft  242 A when the car-side engagement mechanism  2  is in the open state and located on the right when the car-side engagement mechanism  2  is in the closed state. 
     In each of the embodiments described above, the roller  312  or  244  is used as the moving member guided by the fixed cam  33 . However, it is apparent that the moving member is not limited to the roller  312  or  244  and may be a slide shoe member or the like. 
     Moreover, although the lever support shaft  314  is fixed to the driving-side car door  51  through an intermediation of the mount plate  313  in Embodiments 1 to 3, the lever support shaft  314  may be directly fixed to the driving-side car door  51 . 
     Further, by using the resistance spring  35  of Embodiment 2 or the resistance weight  37  of Embodiment 3 together with the lever retention spring  34  according to Embodiments 1 and 4, the resistance spring  35  or the resistance weight  37  can be reduced in size. As a result, the lever main body  311  and the driving cam  24 A can be reduced in size. 
     Further, the configuration for applying the turning force of the driving cam  24 A by adjusting the position of center of gravity of the driving cam  24 A, which is described in Embodiment 5, can be used in place of the lever retention spring  34 , the resistance spring  35 , or the resistance weight  37  so as to be applied to the lever main body  311  of Embodiments 1 to 3 and the driving cam  24 A of Embodiment 4. Moreover, by using the configuration together with the lever retention spring  34 , the resistance spring  35 , or the resistance weight  37 , the lever main body  311  and the driving cam  24 A can be reduced in size. 
     Further, in each of the embodiments described above, the guide surfaces of the cam groove  331  have a linear shape. However, by providing a curve shape, the lever main body  311  or the driving cam  24 A turns more smoothly to smooth the actuation of the first vane  211  and the second vane  212 . 
     REFERENCE SIGNS LIST 
       1  door engagement device,  2  car-side engagement mechanism,  21  engagement vane,  211  first vane,  212  second vane,  213  vane support shaft,  214  cam follower,  22  vane link,  221  upper vane link,  222  lower vane link,  223  link support shaft,  23  base plate,  24 ,  24 A driving cam,  241  cam groove,  242 ,  242 A cam support shaft,  243  connection-bar mount shaft,  244  roller (moving member),  3  engagement-mechanism driving device,  31  lever,  311  lever main body,  312  roller (moving member),  313  mount plate,  314  lever support shaft,  315  connection-bar mount shaft,  316 ,  317  contact portion,  32  stopper,  33  fixed cam,  331  cam groove,  332  resistance spring fixing portion,  333  resistance weight guide,  334  notch portion,  34  lever retention spring,  341  lever spring-fixed point,  341 A cam spring-fixed point,  342 ,  342 A door spring-fixed point,  35  resistance spring,  36  connection bar,  37  resistance weight,  4  door device main body,  41  door hanger,  411  driving-side hanger plate,  412  driven-side hanger plate,  413  hanger roller,  414  driving-side belt gripper,  415  driven-side belt gripper,  42  hanger rail, door driving motor,  44  driving belt,  45  fixed portion,  441  belt,  442  driving pulley,  443  idler pulley,  5  car door,  51  driving-side car door, driven-side car door