Patent Publication Number: US-2015060211-A1

Title: Fall prevention device for an elevator

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a fall prevention device for an elevator and, more particularly, to a fall prevention device preventing entrance into a cab of an elevator not at a correct floor position. 
     Elevators are a convenient tool for transporting people, goods, or cars in a multi-story building or elevated site. An elevator generally includes a shaft extending vertically through a plurality of floors, with a door provided on each floor. The elevator includes a cab movable in the shaft. When the cab reaches the desired floor position, a cab door of the cab is aligned with the door on the floor and opens to allow entry of people, goods, or a car. Ascending and descending of the cab to the desired floor position, opening/closing of the doors and the cab door, and lamp indicators indicating the location of the cab are generally controlled by delicate detection and control of many components. Safety devices including brakes have been provided to avoid casualties resulting from unexpected falling of the cab. 
     However, an accident can still happen in a scenario shown in  FIG. 7 . Namely, the door  41  on a floor opens without the cab  42  (and its cab door  421 ) present to enter into. When the door  41  opens, casualties occur if a person or goods or a car moves in a hurry without checking the position of the cab  42 . For example, a person would fall into the shaft  43  and be injured or even die. The tragedy often results from malfunction of the components. However, safety risks still exist no matter delicate control and surveillance and high-level safety devices are provided. 
     Thus, a need exists for a novel fall prevention device for an elevator for reliably preventing casualties even if the cab is not at a correct floor position. 
     BRIEF SUMMARY OF THE INVENTION 
     A fall prevention device according to the present invention includes a shaft adapted to extend vertically through a multi-story building in a vertical direction, with the multi-story building including a plurality of floors. A door is adapted to be provided on each of the plurality of floors. A cab is movably mounted in the shaft and includes a cab door. A movement device includes a power mechanism and first and second grid structures directly or indirectly connected to the power mechanism. The first grid structure has a first end fixed to a top side of the cab at a location adjacent to the cab door. The second grid structure has a first end fixed to a bottom side of the cab at a location adjacent to the cab door. Each of the first and second grid structure includes a plurality of rails spaced from each other in a width direction perpendicular to the vertical direction. The movement device further includes a first support device in a top end of the shaft and a second support device in a bottom end of the shaft. The first and second support devices respectively support the first and second grid structures. 
     In a case that the door is opened but the cab is not at the correct floor position, the door is aligned with the first or second grid structure even though the door is not aligned with the cab door of the cab. The first or second grid structure provides a warning effect to a user intended to use the cab. 
     In an example, a second end of the first grid structure is integrally connected with a second end of the second grid structure. The power mechanism is an elevating mechanism for moving the cab in the shaft in the vertical direction. Movement of the cab in the vertical direction causes reciprocal movement of the first and second grid structures in an annular path. The first support device includes a plurality of first guiding rollers arranged in the width direction. The first support device further includes a plurality of second guiding rollers respectively aligned with the plurality of first guiding rollers. The second support device includes a plurality of third guiding rollers arranged in the width direction. The second support device further includes a plurality of fourth guiding rollers respectively aligned with the plurality of third guiding rollers. 
     In another example, the power mechanism includes an upper reel rotatably mounted in the upper end of the shaft and a lower reel rotatably mounted in the lower end of the shaft. The first grid structure has a second end fixed to the upper reel. The second grid structure has a second end fixed to the lower reel. The upper reel includes a spool forming the first support device. The lower reel includes a spool forming the second support device. 
     Each rail of the first and second grid structures can be formed by a metal cable, a cloth rope, a belt, or a chain. 
     The present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention described in connection with the drawings. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an elevator with a fall prevention device according to the present invention. 
         FIG. 2  is a schematic side view illustrating a building in which the elevator of  FIG. 1  is mounted, with a cab door of a cab of the elevator opened and aligned with an opened door on a floor of the building. 
         FIG. 3  is a schematic cross sectional view of the building and the elevator of  FIG. 2 . 
         FIG. 4  is a schematic side view similar to  FIG. 2 , with the cab door of the cab opened but not aligned with the opened door of the floor. 
         FIG. 5  is a schematic cross sectional view of the building and the elevator of  FIG. 4 . 
         FIG. 6  is a view similar to  FIG. 5 , illustrating another example of the elevator according to the present invention, with the cab door of the cab opened but not aligned with the opened door on a floor. 
         FIG. 7  is a schematic cross sectional view of a conventional elevator, illustrating an accident resulting from a cab door of a cab not aligned with an opened door on a floor. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to  FIGS. 1-3 , a fall prevention device for an elevator according to the present invention includes a shaft  1  adapted to extend vertically through a multi-story building in a vertical direction, with the multi-story building including a plurality of floors. A door  10  is adapted to be provided on each floor. 
     A cab  2  is movably mounted in the shaft  1  and includes a cab door  21 . A movement device  3  includes a power mechanism  30  and first and second grid structures  31  and  32  directly or indirectly connected to the power mechanism  30 . The first grid structure  31  has a first end fixed to a top side of the cab  2  at a location adjacent to the cab door  21 . The second grid structure  32  has a first end fixed to a bottom side of the cab  2  at a location adjacent to the cab door  21 . Each of the first and second grid structure  31  and  32  includes a plurality of rails  311 ,  321  spaced from each other in a width direction perpendicular to the vertical direction. Preferably, each rail  311 ,  321  of the first and second grid structures  31  and  32  is formed by a metal cable, a cloth rope, a belt, or a chain and can be selected according to needs. 
     The movement device  3  further includes a first support device  11  in a top end of the shaft  1  and a second support device  12  in a bottom end of the shaft  1 . The first and second support devices  11  and  12  respectively support the first and second grid structures  31  and  32 . 
     With reference to  FIGS. 4 and 5 , in a case that the door  10  is opened but the cab  2  is not at the correct floor position, the door  10  is aligned with the first or second grid structure  31 ,  32  even though the door  10  is not aligned with the cab door  21  of the cab  2 . The first or second grid structure  31 ,  32  provides a warning effect to a user intended to use the cab  2 . The first and second grid structures  31  and  32  can be painted with fluorescent paint, reflective paint, or eye-catching paint to enhance the warning effect such that the user would hesitate at the sight of the first or second grid structure  31 ,  32 , reducing the risks of moving towards the first or second grid structure  31 ,  32  and falling into the shaft  1 . 
     Even if the user, a car, or goods move towards the door  10 , the user, car, or goods will be stopped by the first or second grid structure  31 ,  32 , providing a reliable fall prevention effect. The spacing between rails  311 ,  321  can be adjusted according to actual operation and installation to reliably prevent the user, car, or goods from falling into the shaft  1 . 
     In the example shown in  FIGS. 1-5 , the second end of each of the first and second grid structures  31  and  32  is integrally connected with the second end of the second grid structure  32 . Furthermore, the power mechanism  30  is an elevating mechanism for moving the cab  2  in the shaft  1  in the vertical direction. Movement of the cab  2  in the vertical direction causes reciprocal movement of the first and second grid structures  31  and  32  in an annular path. The first support device  11  includes a plurality of first guiding rollers  111  arranged in the width direction. The first support device  11  further includes a plurality of second guiding rollers  112  respectively aligned with the first guiding rollers  111 . Each rail  311  of the first grid structure  31  is wound around one of the first guiding rollers  111  and one of the second rollers  112 , providing a stable support for the first grid structure  31 . Even if the cab  2  is out of control and falls, the first grid structure  31  provides an auxiliary braking effect. The second support device  12  includes a plurality of third guiding rollers  121  arranged in the width direction. The second support device  12  further includes a plurality of fourth guiding rollers  122  respectively aligned with the third guiding rollers  121 . Each rail  321  of the second grid structure  32  is wound around one of the third guiding rollers  121  and one of the fourth rollers  122 , providing a stable support for the second grid structure  32 . Even if the cab  2  is out of control and falls, the second grid structure  32  provides an auxiliary braking effect. 
     In another example shown in  FIG. 6 , the power mechanism  30  includes an upper reel  301  rotatably mounted in the upper end of the shaft  1  and a lower reel  302  rotatably mounted in the lower end of the shaft  1 . The second end of the first grid structure  31  is fixed to the upper reel  301 . The second grid structure  32  is fixed to the lower reel  302 . The upper reel  301  includes a spool  301 A forming the first support device  11 , and the lower reel  302  includes a spool  302 A forming the second support device  12 . Thus, the first and second grid structures  31  and  32  can reciprocatingly move in an annular path. 
     Although specific embodiments have been illustrated and described, numerous modifications and variations are still possible without departing from the scope of the invention. The scope of the invention is limited by the accompanying claims.