Patent Publication Number: US-2012024636-A1

Title: Elevator derailment detecting apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to an elevator derailment detecting apparatus that detects disengagement of an ascending/descending body from a guide rail due to earthquakes, etc. 
     BACKGROUND ART 
     In conventional elevator derailment detecting apparatuses, a contact is mounted to a counterweight, and an electrical conductor is installed parallel to a guide rail inside a hoistway. Thus, if the counterweight disengages from the guide rail, dislodgment is detected by the contact contacting the electrical conductor (see Patent Literature 1 and 2, for example). 
     CITATION LIST 
     Patent Literature 
     [Patent Literature 1] 
     Japanese Utility Model Laid-Open No. SHO 53-145668 (Gazette) 
     [Patent Literature 2] 
     Japanese Patent Laid-Open No. 2003-321169 (Gazette) 
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     Because conventional derailment detecting apparatuses such as those described above are configured on the assumption that the ascending/descending body is grounded by a main rope that is constituted by an electrical conductor, it has not been possible to detect counterweight derailment if a main rope is used that has an outer circumference that is covered by an insulating body. 
     The present invention aims to solve the above problems and an object of the present invention is to provide an elevator derailment detecting apparatus that can detect derailment of an ascending/descending body even if the ascending/descending body is not grounded by a main rope. 
     MEANS FOR SOLVING THE PROBLEM 
     In order to achieve the above object, according to one aspect of the present invention, there is provided an elevator derailment detecting apparatus including: first and second conducting wires that are disposed inside a hoistway parallel to a direction of raising and lowering of an ascending/descending body; a first contact that is mounted to the ascending/descending body, and that contacts the first conducting wire if the ascending/descending body disengages from a guide rail; a second contact that is mounted to the ascending/descending body, and that contacts the second conducting wire if the ascending/descending body disengages from the guide rail; and a detecting portion that detects contact of the first contact with the first conducting wire, wherein: the first conducting wire is set to positive electric potential; the second conducting wire is set to ground electric potential; and the detecting portion detects by presence or absence of conduction between the first contact the first conducting wire whether or not the ascending/descending body is disengaged from the guide rail. 
     EFFECTS OF THE INVENTION 
     In an elevator derailment detecting apparatus according to the present invention, because the first conducting wire is set to positive electric potential, and the second conducting wire is set to ground electric potential, and the detecting portion detects by the presence or absence of conduction between the first contact and the first conducting wire whether or not the ascending/descending body is disengaged from the guide rail, the ascending/descending body can be set to ground electric potential if the second contact contacts the second conducting wire, enabling derailment of the ascending/descending body to be detected even if the ascending/descending body is not grounded by a main rope. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevation that shows an example of an elevator apparatus to which a derailment detecting apparatus according to Embodiment 1 of the present invention is applied; 
         FIG. 2  is a rear elevation that shows a counterweight from  FIG. 1 ; 
         FIG. 3  is a plan that shows the counterweight from  FIG. 2 ; 
         FIG. 4  is a plan that shows part of an elevator derailment detecting apparatus according to Embodiment 2 of the present invention; 
         FIG. 5  is a plan that shows part of an elevator derailment detecting apparatus according to Embodiment 3 of the present invention; 
         FIG. 6  is a plan that shows part of an elevator derailment detecting apparatus according to Embodiment 4 of the present invention; 
         FIG. 7  is a plan that shows part of an elevator derailment detecting apparatus according to Embodiment 5 of the present invention; and 
         FIG. 8  is a plan that shows part of an elevator derailment detecting apparatus according to Embodiment 6 of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Preferred embodiments of the present invention will now be explained with reference to the drawings. 
     Embodiment 1 
       FIG. 1  is a side elevation that shows an example of an elevator apparatus to which a derailment detecting apparatus according to Embodiment 1 of the present invention is applied. In the figure, a machine room  12  is disposed in an upper portion of a hoistway  11 . A machine base  13  is installed inside the machine room  12 . A hoisting machine  14  is supported on the machine base  13 . The hoisting machine  14  has a driving sheave  15  and a hoisting machine main body  16 . The hoisting machine main body  16  has: a hoisting machine motor that rotates the driving sheave  15 ; and a hoisting machine brake that brakes the rotation of the driving sheave  15 . 
     A deflecting sheave  17  is mounted to the machine base  13 . A plurality of main ropes  18  that function as a suspending means are wound around the driving sheave  15  and the deflecting sheave  17 . Ropes or belts are used as the main ropes  18 . The main ropes  18  include: an inner layer that includes a plurality of steel strands; and a resin coating layer (an insulator layer) that is coated onto an outer circumference of the inner layer. 
     A car  19  is suspended on first end portions of the main ropes  18 . Specifically, the car  19  is suspended inside the hoistway  11  by the main ropes  18  on a first side of the driving sheave  15 . A counterweight  20  that constitutes an ascending/descending body is suspended on second end portions of the main ropes  18 . Specifically, the counterweight  20  is suspended by the main ropes  18  on a second side of the driving sheave  15 . 
     A pair of car guide rails  21  that guide raising and lowering of the car  19  and a pair of counterweight guide rails  22  that guide raising and lowering of the counterweight  20  are installed inside the hoistway  11 . The car guide rails  21  are disposed vertically so as to face each other. The counterweight guide rails  22  are disposed vertically so as to face each other. 
     The counterweight  20  is disposed behind the car  19  so as to face a back surface of the car  19  when positioned level with the car  19 . A safety device  23  that makes the car  19  perform an emergency stop by engaging with the car guide rails  21  is mounted to the car  19 . 
       FIG. 2  is a rear elevation that shows a counterweight  20  from  FIG. 1 , and  FIG. 3  is a plan that shows the counterweight  20  from  FIG. 2 . The counterweight guide rails  22  are fixed to wall surfaces of the hoistway  11  by a plurality of rail brackets  24 . A plurality of (in this example, four) counterweight guide shoes  25  that engage with the counterweight guide rails  22  are mounted to the counterweight  20 . 
     Roller guide shoes or sliding guide shoes are used as the counterweight guide shoes  25 . The counterweight guide shoes  25  are mounted to upper and lower end portions on two sides in a width direction of the counterweight  20 . 
     The counterweight  20  has: a metal frame body  26 ; and a plurality of weight main bodies  27  that are stacked inside the frame body  26 . The main ropes  18  are connected to an upper end portion of the frame body  26 . 
     First and second conducting wires  1  and  2  are disposed inside the hoistway  11  in a vicinity of the counterweight  20 . The first and second conducting wires  1  and  2  are disposed parallel to the direction of raising and lowering of the counterweight  20 , i.e., vertically, over almost an entire length of the hoistway  11 . A predetermined tension is applied to the first and second conducting wires  1  and  2 . 
     The first conducting wire  1  is disposed in a vicinity of one of the counterweight guide rails  22 , i.e., in a vicinity of a first end portion in the width direction of the counterweight  20 . The second conducting wire  2  is disposed in a vicinity of one of the counterweight guide rails  22 , i.e., in a vicinity of a second end portion in the width direction of the counterweight  20 . The first and second conducting wires  1  and  2  are disposed on an opposite side of the counterweight guide rails  22  from the car  19  (the hoistway wall side). 
     A ring-shaped first contact  3  is mounted to a first end portion in a width direction of an upper end portion of the frame body  26  by means of a first supporting body  4 . The first conducting wire  1  is inserted approximately centrally through the first contact  3 . In other words, the first contact  3  surrounds the first conducting wire  1  so as to have a predetermined clearance. 
     A ring-shaped second contact  5  is mounted to a second end portion in a width direction of an upper end portion of the frame body  26  by means of a second supporting body  6 . The second conducting wire  2  is inserted approximately centrally through the second contact  5 . In other words, the second contact  5  surrounds the second conducting wire  2  so as to have a predetermined clearance. 
     The first contact  3 , the first supporting body  4 , the second contact  5 , and the second supporting body  6  are each constituted by an electroconductive material. The first contact  3  and the second contact  5  are electrically connected through the first supporting body  4 , the frame body  26 , and the second supporting body  6 . 
     If the counterweight  20  disengages from the counterweight guide rails  22  and displaces horizontally, the first contact  3  contacts the first conducting wire  1 , and the second contact  5  contacts the second conducting wire  2 . The first and second contacts  3  and  5  have an identical shape and an identical size to each other, and come into contact with the first and second conducting wires  1  and  2  almost simultaneously in the event of derailment of the counterweight  20 . 
     During normal operation of the elevator, the first conducting wire  1  is set to positive electric potential, and the second conducting wire  2  is set to ground electric potential. A detecting portion  7  ( FIG. 2 ) that detects contact of the first contact  3  with the first conducting wire  1  is connected to the first conducting wire  1 . The detecting portion  7  detects by the presence or absence of conduction between the first contact  3  and the first conducting wire  1  whether or not the counterweight  20  is disengaged from the counterweight guide rails  22 . An electric potential detector that detects the electric potential of the first conducting wire  1 , for example, is used as the detecting portion  7 . 
     The derailment detecting apparatus according to Embodiment 1 includes the first and second conducting wires  1  and  2 , the first and second contacts  3  and  5 , the first and second supporting bodies  4  and  6 , and the detecting portion  7 . 
     Next, operation will be explained. If the counterweight  20  disengages from the counterweight guide rails  22  due to an earthquake, etc., the counterweight  20  is displaced frontward, rearward, to the left, or to the right from the normal raising and lowering position. At that point, the first and second contacts  3  and  5  are displaced together with the counterweight  20 , and come into contact with the first and second conducting wires  1  and  2 , respectively. 
     When the first and second contacts  3  and  5  come into contact with the first and second conducting wires  1  and  2 , respectively, the first conducting wire  1  is electrically connected to the second conducting wire  2  through the first contact  3 , the first supporting body  4 , the frame body  26 , the second supporting body  6 , and the second contact  5 , and reaches identical electric potential to the second conducting wire  2 , i.e., ground electric potential. When the first conducting wire  1  reaches ground electric potential, this is detected by the detecting portion  7 , and disengagement of the counterweight  20  from the counterweight guide rails  22  is detected. 
     In a derailment detecting apparatus of this kind, because the counterweight  20  is set to ground electric potential when the second contact  5  contacts the second conducting wire  2 , it becomes possible to detect derailment of the counterweight  20  even if surfaces of the main ropes  18  are covered by insulating bodies and the counterweight  20  is not grounded by the main ropes  18 . 
     Because the first and second conducting wires  1  and  2  are disposed in a vicinity of the counterweight guide rails  22 , the occurrence of derailment can be detected immediately. 
     In addition, because the first and second contacts  3  and  5  are configured so as to have identical shape and identical size to each other, the type of contact  3  and  5  can be unified, enabling manufacturing costs to be reduced. 
     In addition, because the first and second contacts  3  and  5  are respectively mounted to different supporting bodies  4  and  6 , layout freedom can be improved. 
     Embodiment 2 
     Next,  FIG. 4  is a plan that shows part of an elevator derailment detecting apparatus according to Embodiment  2  of the present invention. In Embodiment 1, the first and second contacts  3  and  5  had an annular shape, but in Embodiment 2, first and second contacts  3  and  5  have a quadrangular loop shape. The first and second contacts  3  and  5  are disposed nearer to a car  19  than counterweight guide rails  22 . The rest of the configuration is similar to that of Embodiment 1. 
     According to a configuration of this kind, it is also possible to detect derailment of the counterweight  20  while using main ropes  18  in which surfaces are covered by insulating bodies, in a similar manner to Embodiment 1. 
     Moreover, shapes of the first and second contacts  3  and  5  are not limited to being circular or quadrangular, and may also be elliptical, triangular, polygons that are greater than or equal to pentagonal, or closed free-form curve shapes, etc. 
     Embodiment 3 
     Next,  FIG. 5  is a plan that shows part of an elevator derailment detecting apparatus according to Embodiment  3  of the present invention. In this example, a second contact  5  that is of smaller size (has a smaller diameter) than a first contact  3  is used. In other words, in a normal state (a state in which derailment has not occurred), clearance between the second contact  5  and a second conducting wire  2  is smaller than clearance between the first contact  3  and the first conducting wire  1 . The rest of the configuration is similar to that of Embodiment 1. 
     In a derailment detecting apparatus of this kind, when derailment of the counterweight  20  occurs, the second contact  5  and the second conducting wire  2  come into contact, and then the first contact  3  and the first conducting wire  1  come into contact. Thus, derailment can be detected at the instant at which the first contact  3  and the first conducting wire  1  come into contact. 
     If the second contact  5  and the second conducting wire  2  come into contact due to building sway instead of derailment, because derailment is not detected simply by the counterweight  20  reaching ground electric potential if the first contact  3  and the first conducting wire  1  are not in contact, the risk of false detection is not increased. 
     Embodiment 4 
     Next,  FIG. 6  is a plan that shows part of an elevator derailment detecting apparatus according to Embodiment 4 of the present invention. In this example, first and second contacts  3  and  5  are mounted to a frame body  26  by means of a common supporting body  8 . Consequently, the first and second conducting wires  1  and  2  are disposed in close proximity to each other. The first and second contacts  3  and  5  have quadrangular loop shapes. In addition, a second contact  5  that is smaller than the first contact  3  is used. The rest of the configuration is similar to that of Embodiment 1. 
     Even if the first and second contacts  3  and  5  are supported by the common supporting body  8  in this manner, it becomes possible to detect derailment of the counterweight  20  while using main ropes  18  in which surfaces are covered by insulating bodies, in a similar manner to Embodiment 1. The number of parts is also reduced, enabling manufacturing costs to be reduced. 
     Embodiment 5 
     Next,  FIG. 7  is a plan that shows part of an elevator derailment detecting apparatus according to Embodiment 5 of the present invention. In this example, first and second contacts  3  and  5  are integrated, and are mounted to a frame body  26  by means of a common supporting body  8 . Specifically, the first and second contacts  3  and  5  have quadrangular loop shapes, and share one side. Consequently, the first and second conducting wires  1  and  2  are disposed in close proximity to each other. The rest of the configuration is similar to that of Embodiment 1. 
     Even if the first and second contacts  3  and  5  are integrated in this manner, it becomes possible to detect derailment of the counterweight  20  while using main ropes  18  in which surfaces are covered by insulating bodies, in a similar manner to Embodiment 1. The number of parts is also reduced, enabling manufacturing costs to be reduced. 
     Embodiment 6 
     Next,  FIG. 8  is a plan that shows part of an elevator derailment detecting apparatus according to Embodiment 6 of the present invention. In this example, a contact  9  that has a quadrangular loop shape is mounted to a frame body  26  by means of a supporting body  8 . First and second conducting wires  1  and  2  are inserted approximately centrally through the contact  9 . Specifically, the contact  9  surrounds the first and second conducting wires  1  and  2  together so as to leave a predetermined clearance. The first and second conducting wires  1  and  2  are disposed in close proximity to each other. The rest of the configuration is similar to that of Embodiment 1. 
     According to a configuration of this kind, it is also possible to detect derailment of the counterweight  20  while using main ropes  18  in which surfaces are covered by insulating bodies. The number of parts is also reduced, enabling manufacturing costs to be reduced. 
     Moreover, in Embodiments 1 through 6, cases in which the ascending/descending body is a counterweight  20  are shown, but the car  19  may also be set as the ascending/descending body. In other words, the contacts  3  and  5  or the contact  9  may also be mounted to the car  19  so as to detect disengagement of the car  19  from the car guide rails  21 . 
     The present invention is naturally not limited to the elevator in  FIG. 1  and can be applied to various types and layouts of elevator.