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FIELD OF THE INVENTION 
       [0001]    The invention generally relates to fire and/or smoke barrier systems and particularly to roll down smoke and/or gas barrier systems. 
       BACKGROUND 
       [0002]    Smoke and in noxious gases can be very dangerous to occupants during a building fire. Generally, noxious gases pose a more significant risk to the occupants than the fire itself. This is particularly true for multi-story buildings that are equipped with an elevator. Elevator shafts provide significant paths by which smoke and noxious gases can spread rapidly throughout a building, thus putting even those occupants of a building in danger who are far away from the fire. 
         [0003]    To prevent the spread of dangerous gases, many devices and assemblies have been designed to cut off possible paths for gases. For example, U.S. Pat. No. 7,028,742 B2 describes a system and method for sealing openings and in response to smoke, noxious fumes, or contaminated air using a roll-down barrier. A similar solution has been disclosed in US 2006/0226103 A1, U.S. Pat. No. 5,195,594, and U.S. Pat. No. 5,383,510. 
         [0004]    A typical high-rise building has many elevator doors and thus requires a significant number of these systems. 
         [0005]    It is desirable to have a simple and robust closure member control system in place. 
         [0006]    Due to the law and regulations, fire and/or smoke protection systems must be tested regularly, e. g. every few months. It is desirable to make these tests as easy and as a little time-consuming as possible. 
       SUMMARY 
       [0007]    An exemplary embodiment of the invention is to provide a closure member control system that overcomes the drawbacks of the prior art. 
         [0008]    An exemplary closure member control system would include a housing, a fire and/or smoke barrier which is at least partially wound and unwound from a spool, and a drive mechanism for moving the barrier between a stowed and a deployed position. The housing has an interior, and opening to the interior, and closure member which is movable relative to the opening between an open and a closed position. The closure member covers at least a portion of the opening in the closed position and does not cover the portion when in the open position. The fire and/or smoke barrier is coupled to the housing and moves between a stowed position and a deployed position. The barrier is located within the interior of the housing when it is in the stowed position, and expends past the opening to the housing interior when in the deployed position. The barrier is wound on a spool located generally within the interior of housing. The drive mechanism is operatively coupled to the barrier such that it can drive the barrier to at least one of the stowed position and the deployed position. The drive mechanism includes one or more cords coupled to the spool, for example, on each side of the spool, which retain the spool and the barrier in the stowed position. The cord(s) is movable to lower the spool and a portion of the barrier past the opening in the housing as the barrier moves from the stowed position to the deployed position. The closure member is position to be prevented from closing by means of the cord(s) when the closure member is in the open position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  shows cross sectional views of an embodiment of the present invention. The fire and/or smoke barrier is shown in a position between a stowed position and a deployed position in the A-A cross sectional view. 
           [0010]      FIG. 2  shows the cross section of an embodiment of the present invention, wherein the spool with the fire a smoke barrier is shown in the stowed position and in two positions between the stowed position and the deployed position (identified by dashed lines). 
           [0011]      FIGS. 3 a  and 3 b    show respectively side and cross-sectional views of another embodiment of the present invention in which the closure member has tip elements for contacting the cords. 
           [0012]      FIGS. 4 a , 4 b , 4 c    show a further embodiment of the present invention in which the cord has a thickening and the closure member has an eye for positive engagement with the thickening in order to close the closure member. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]      FIG. 1  shows a fire and/or smoke protection system  10  for reversibly shutting off an opening  12 , e. g. an elevator door, by means of a fire and/or smoke barrier  14 . The opening  12  is provided in a wall  16  of a building. 
         [0014]    The fire and/or smoke barrier  14  can be wound on a spool  18 . The fire and/or smoke barrier  14  comprises a magnetic strip  20 . 1  and  20 . 2  on each side for attachment to a ferromagnetic frame  22  of the opening  12 . Magnetic strips  20 . 1 ,  20 . 2  provide a smoke-proof seal so that the fire and/or smoke barrier  14  can seal of the opening  12  in a smoke proof way. 
         [0015]    The fire and/or smoke protection system  10  comprises a housing  24  that may be made from a metal sheet or another suitable material. When the fire and/or smoke barrier  14  is completely wound on the spool  18 , it is located within the housing  24 , as can be seen in the right picture depicting a sectional view along C-C and with reference to  FIG. 2 . When the fire and/or smoke barrier  14  is partly unwound from the spool, the spool  18 ′—takes the position that is drawn in dashed lines. The reference numeral  18 ″ shows the spool in its deployed position. 
         [0016]    The housing  24  comprises a closure member  26 , which may be a flap, as will be described in more detail below. 
         [0017]    The fire and/or smoke protection system  10  has a drive mechanism  28 , motor  30  and a control  32 . The control  32  is connected to a central alarm system. If the central alarm system sends an alarm signal or fails to send an ok signal, the control  32  interrupts the power supply of the motor  30  so that the spool  18  with the fire and/or smoke barrier  14  wound on it moves down, e.g., because of its own weight. In this case, the motor  30  acts as brake so that the speed of the spool  18  does not exceed a preset maximum speed. 
         [0018]      FIG. 2  shows a detailed cross section of the fire and/or smoke protection system  10  according to  FIG. 1 .  FIG. 2  shows that the closure member  26  is pivotably mounted to the housing  24 . The housing  24  is mounted to the wall  16  e. g. by screws (not shown). The reference numeral  18  refers to the spool in its stowed position. The spring  36  or the counter weight  34  may be omitted. However, the combination of both can be particularly advantageous. 
         [0019]    The fire and/or smoke protection system  10  may comprise a magnet  38 . It is possible that the counter weight  34  also is, is associated with, or forms at least part of the magnet  38 . In this embodiment the magnet  38  may cling to the housing  24 , as shown in  FIG. 2 . The counter weight  34  is then preferably made from a ferromagnetic material, e. g. steel or iron. The magnet  38  firmly closes the flap  26  when it is in its closed position, e. g. when the spool  18  is in its stowed position. 
         [0020]    When the motor  30  is no longer powered or receives a signal to deploy the fire and/or smoke barrier  14 , a cord  40  may be unwound from a spool  42  that is connected to the motor  30 . As the spool  42  turns, the cord  40  may be wound onto a bobbin  44  that is connected to the spool  18  or is part of it. After a short period of time, the cord  40  (as well as the assemblage  18 ) comes in contact with the flap  26  and pushes it open, as is shown in solid line  40 ″. The closure member  26 ′ is thus prevented from closing by the cord  40 ″. 
         [0021]      FIGS. 3 a  and 3 b    shows another embodiment of the present invention in which the closure member  26  comprises tip elements  46 . 1 ,  46 . 2  that are designed so that they can only contact the cord  40 , as opposed to either the bobbin  44  and the fire and/or smoke barrier  14 . As shown in  FIG. 3B , there may be two strings of cord  40 . 1 ,  40 . 2  that are separate from each other and are each wound onto one bobbin  44 . 1  and  44 . 2  respectively. As an alternative, there may be only one cord having two sections on each side of the fire and/or smoke barrier  14 . As illustrated in  FIG. 3 a   , the tip elements  46 . 1  and  46 . 2  can be partially concave for better interaction with the cords, and may also be magnetic. The cord(s)  40 ,  40 . 1 , or  40 . 2  may be made of or include a ferromagnetic material such as steel or iron so that the cord may be attracted by magnetic tip elements. 
         [0022]      FIGS. 4 a  to 4 c    show another embodiment of the present invention in which the cord  40  that is wound onto the bobbin  44 . 1  comprises a thickening  48  which may be glued or screwed or otherwise fastened to the cord  40 . In the position shown in  FIG. 4 a   , the part of the cord  40  with the thickening  48  is wound on the bobbin  54 . 1 . 
         [0023]    The closure member  26  comprises a spring element  50  that has an eye  52 . The cord  40  runs through the eye  52 . The eye  52  is big enough so that the cord  40  can past through the eye  52  more or less unaffectedly, but too small for the thickening  48 . 
         [0024]      FIG. 4 b    shows a situation in which the thickening  48  has reached the eye  52 . Further upward motion of the cord  40  in order to a move the spool  18  in the upward direction will cause a locking engagement of the thickening  48  with the eye  52 . As a consequence, the eye  52  will be moved in the upward direction thus tensioning the spring element  50 . This causes the closure number  26  to close. 
         [0025]      FIG. 4 c    shows situation in which the spring element  50  has closed the closure member  26 . In this embodiment, there is no need for a counter weight or a magnet. However, it is also possible to provide a counter weight and/or a magnet as shown in  FIG. 3   a.

Summary:
A closure member control system for roll down smoke and/or gas barrier system includes a closure member which, when closed, maintains a spool with the barrier wound thereon within a housing. On deployment, the closure member opens and is prevented from closing by one or more cords connected to the spool.