Abstract:
An elevator control box is constructed to avoid propagating a cable fire in the control box into the elevator shaft. The control box is incorporated in a wall of the elevator shaft and has an opening through which a cable is guided. A fireproof element is positioned in the control box surrounding the cable in the region of the opening.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to a control box for an elevator. 
     The European patent document EP 0 680 921 B1 shows a control box for an elevator that is installed in a wall of the elevator shaft at the floor. A fireproof door is in fact provided at the control box and protects the electrical subassemblies of the control box against fire on the floor and the floor against fire in the control box, but in the case of fire in the control box the fire is not prevented from propagating into the shaft in which the elevator car moves. Thus, it is not guaranteed that in the case of fire in the control box the persons located in the shaft or in the car are sufficiently protected. This form of embodiment therefore does not fulfil the technical safety requirements to the full extent. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a control box for an elevator in which it is ensured with sufficient certainty that a fire in the control box, especially a cable fire, cannot propagate into the shaft space. 
     The present invention concerns a control box for an elevator, which is provided in a wall of an elevator shaft, has an opening through which a cable is guided. In addition, the control box includes a fireproof element that surrounds the cable in the region of the opening. 
     It is of particular advantage to provide the opening in the lower region of the control box, because the fire propagation can thereby be further reduced. It also is of advantage to construct the fireproof element from ceramic fiber, rock wool, glass wool, a silicate compound or gypsum. A sufficient fire protection insulation is thereby guaranteed. In order to further increase the fire protection insulation, the cable can be advantageously tightly enclosed by the fireproof element. 
     In addition, it is of advantage to provide two clamping elements and a clamping device, wherein the fireproof element is clamped in place between the two clamping elements by means of the clamping device. The fireproof element thereby tightly surrounds the cable, whereby a high fire protective isolation is achieved. The clamping device can advantageously comprise a screw and a nut. 
     It is of advantage if the control box includes a foot, wherein the screw as a component of the clamping device can additionally serve as the foot. The control box can advantageously stand on the floor in a recess. The cable can be an electrical cable or a cable for actuation of a brake. 
     Finally, it can also be of advantage to provide the opening in the upper region of the control box. The cable guidance into the shaft is thereby optimized. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which: 
     FIG. 1 is a perspective view of a control box according to the present invention equipped with electronic subassemblies; 
     FIG. 2 is a fragmentary top plan view of a first possible arrangement of the control box shown in FIG. 1 in the region of a floor; 
     FIG. 3 is a fragmentary top plan view of a second possible arrangement of the control box shown in FIG. 1 in the region of a floor; 
     FIG. 4 is a fragmentary perspective view of the control box shown in FIG. 1 with an upper opening, through which a cable for actuation of a brake is guided; 
     FIG. 5 is a vertical cross-section of an upper portion of the control box shown in FIG. 1 with an upper opening, through which a cable is guided; 
     FIG. 6 is a vertical cross-section of a lower portion of the control box shown in FIG. 1 with an opening through which a cable is guided; 
     FIG. 7 is a view taken along the line D—D in FIG. 6; and 
     FIG. 8 is a horizontal cross-section of a bottom portion of the control box shown in FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An elevator control box  4  according to the present invention is shown in FIG. 1 as including a hollow box or housing having a front wall  4 . 1  with an opening  4 . 2  formed therein. Service personnel can gain access to electronic components or subassemblies  11  in a hollow interior of the control box  4  by way of a door  9  hinged to the box to selectively close the opening  4 . 2 . As a rule, the door  9  is mounted to open along an edge of the opening  4 . 2  towards the adjacent floor (FIGS. 2 and 3) so that the electronic components  11  are readily accessible from the floor. The control box  4  can be connected with the frame of the shaft door by means of, for example, a connecting plate  10  extending outwardly from a side wall  4 . 3  of the box. 
     In a top plan view FIG. 2, the control box  4  is shown mounted on the left hand side of a shaft door  12  as viewed from a floor  8 . The control box  4  is disposed on the floor  8  and separates an elevator shaft  2  from the floor. The electrical and electronic subassemblies are accessible from the floor  8  by way of the door  9 . The control box  4  is attached at one side with a shaft wall  1  and on the other side with a frame of the shaft door  12 . The control box  4  is in that case arranged in such a manner that the opening in the shaft wall  1  in which the control box and the shaft door  12  are positioned has minimal dimensions. The shaft wall opening in that case merely has to be selected to be of such width that the shaft door  12  can open unhindered. The control box  4  is placed in the shaft wall opening in such a manner that the shaft door  12  is disposed in the opened state behind the control box. 
     In FIG. 2, the shaft door  12  is shown as a centrally opening four-panel telescopic door. However, the control box  4  is in principle also usable with other types of shaft doors. 
     In the case of the embodiment shown in FIG. 3, it is substantially the same as the embodiment shown in FIG.  2 . The only difference is that merely the control box  4  is arranged on the other side of the opening in the shaft wall  1 . 
     In the FIG. 4, an upper end of the control box  4  is shown in perspective view with a pair of openings  5  formed in a top wall  4 . 4 . After opening of the door  9  (shown in phantom) of the control box  4 , a lever  13  for release of a brake is accessible. The lever  13  for release of the brake of the elevator is connected with a cable  3 . The cable  3  can be, for example, a Bowden pull. The force applied in actuation of the lever  13  is transmitted by way of the cable  3  to the brake (not shown) arranged at the drive unit of the elevator in order to manually control the movement of the elevator car. The cable  3  is guided through one of the openings  5  in the top wall  4 . 4  of the control box  4  out into the elevator shaft  2 . The other one of the openings  5  can be optional. Instead of or even in addition to the Bowden pull, an electrical cable can also be guided through one of the openings  5 . 
     The upper end of the control box  4  in conjunction with a cover connecting element  14  is shown in cross-section in FIG.  5 . After the control box  4  has been positioned at the floor and the cable  3  guided through the opening  5  into the elevator shaft  2 , the cover connecting element  14 , also termed a closure panel, is inserted as shown (before and after insertion) and screw-connected with the control box  4 . The cable  3  can be fixed in the control box  4  by means of a fixing element  15 . 
     A fireproof element  6 , for example a ceramic fiber mat, a rock wool mat, a glass wool mat, a mat of a silicate compound or gypsum, is installed in the upper region of the control box  4  inside the top wall  4 . 4  for fire isolation. 
     In order to keep the fireproof element  6  in its position and to lightly bias it so that it completely tightly encloses the cable  3 , the fireproof element  6  can be held by means of a clamping assembly including a first clamping element  7 . 1 , a second clamping element  7 . 2 , and a clamping device such as a screw  7 . 3  and a nut  7 . 4 . The biasing of the fireproof element  6  can be set by way of the screw  7 . 3 . The second clamping element  7 . 2  can be a sheet metal strip, a sheet metal plate or the like in order to achieve a distribution, over an area, of the biasing force produced by the screw  7 . 3 . The first clamping element  7 . 1  is usually a sheet metal strip that forms at least a portion of the top wall  4 . 4  of the control box  4 . The nut  7 . 4  serves as a counter member for the screw  7 . 3 . 
     The use of a ceramic fiber mat as the fireproof element  6  for fire protective isolation has the advantage that this does not lose its mechanical properties even under high temperature. Moreover, the ceramic fiber mat has the advantage that it can be compressed. It thereby prevents gases from passing through the opening  5  of the control box  4 . Finally, the ceramic fiber mat has the advantage that it is simple to mount without the material breaking. 
     The size of the ceramic fiber mat depends on the size of the control box. A three centimeter thick fireproof insulation should usually be sufficient. 
     The opening  5  in the control box  4  for the passage of the cable  3  also can be disposed in a bottom wall  4 . 5  of the control box  4  (as shown in FIG.  6 ), as the cable passage from the control box out into the shaft  2  is more difficult to seal off in the case of an opening in a rear wall  4 . 6  of the control box  4 . 
     In the embodiment shown in FIG. 6, a lower portion of the control box  4  is shown in cross-section. The control box  4  is supported by feet, which are formed by the screws  7 . 3 , on the floor  8 . 
     The control box  4  advantageously stands in a recess formed in the floor  8 . The recess amounts to about ten centimeters so that the cable  3  can be guided underneath the control box  4  into the shaft  2 . The screw  7 . 3  serves as a foot and additionally functions in a second clamping assembly together with the first clamping element  7 . 1 , the second clamping element  7 . 2  and the nut  7 . 4  for compressing the fireproof element  6 . 
     The opening  5  in the control box  4  is advantageously selected to be just sufficiently large for the cable  3  to be able to be conveniently guided through the opening. 
     The cable  3  is fixed in the control box  4  by the fixing element  15 . 
     A section D—D through the control box  4  in FIG. 6 is shown in FIG.  7 . The fixing element  15  can be, for example, a cable tie. Additional clamping elements  7 . 1  and  7 . 2 , nuts  7 . 4  and screws  7 . 3  can obviously be used for fastening and tightening the fireproof element  6 . 
     The use of several of the screws  7 . 3  particularly in the lower portion of the control box  4  has the advantage that the box thereby stands on several feet and thus in a more stable manner. 
     The bottom portion of the control box  4  is illustrated in cross-section plan view in FIG.  8 . The connecting metal plate  10 , as shown in FIG. 1, is not present in the embodiment shown in FIG.  8 . As is apparent from FIG. 8, it is not necessary for the fireproof element  6  to cover the entire bottom wall  4 . 5  of the control box  4 . It merely has to be ensured that the fireproof element is sufficiently present in the region of the opening  5  to surround the cable  3  which is passed through the opening. 
     In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.