Patent Publication Number: US-2022233891-A1

Title: Rope-Lowering Device and Corresponding Lowering Method

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a rope-lowering device for lowering persons from a building or the like, e.g. also including structures like ski lifts, wind turbines, towers, etc., for instance in case of a calamity such as a fire. The invention further relates to a corresponding lowering method. 
     Rope-lowering devices are well-known and typically include:
         an axle arranged to rotate about its longitudinal axis;   a reel connected to the axle;   a rope connected to the reel to be suspended from the reel; and   a brake connected to the axle, which brake is configured to provide a braking force when paying out the rope.       

     Such rope-lowering devices can be used to lower persons from a building, e.g. in case of a calamity such as a fire. Person may be trapped in the building, e.g. due to fire and smoke and may only be able to leave the building safely via a window or balcony. However, even from relatively small heights, jumping of a building may cause serious harm upon impact with the ground. 
     Rope-lowering devices may be connected to the building, permanently or temporarily in case of an emergency, and a person may use the rope to lower said person from the building. When the rope is paid out from the reel, the brake will ensure that the lowering speed of the person remains within limits so that the impact with the ground is reduced and the chance of the person reaching the ground safely is increased. 
     However, a disadvantage of the current devices is that for the next person to use the device to lower the person from the building, the rope needs to be hauled in first. This consumes valuable time and energy. 
     SUMMARY OF THE INVENTION 
     In view of the above it is an object of the invention to provide a rope-lowering device which allows to quickly lower a plurality of persons from a building in case of an emergency. 
     The object of the invention is achieved by a rope-lowering device for lowering persons from a building or the like, comprising:
         an axle arranged to rotate about its longitudinal axis;   a first reel connected or connectable to the axle;   a second reel connected or connectable to the axle;   a brake connected to the axle, which brake is configured to provide a braking force to the axle independent of a direction of rotation;   a first rope connected to the first reel to be suspended from the first reel; and   a second rope connected to the second reel to be suspended from the second reel,       

     wherein the rope-lowering device is configured such that when both the first and second reels are connected to the axle, paying out one of the first and second rope will automatically cause the other one of the first and second rope to be hauled in. 
     It is explicitly mentioned here that the term “rope” needs to be interpreted broadly as being any kind of elongated flexible element with tensile strength that can be wound on a reel and is able to carry the weight of a person suspended from the rope-lowering device. Hence, it may include cords, strings, twines, bands and be made of any kind of material including but not limited to metal, plastics, fabrics or other yarns, fibers or strands. The rope may further include elements twisted or braided together. 
     In an embodiment, the first reel has a disconnected state, in which the axle is free to rotate relative to the first reel, and a connected state, in which the first reel is connected to the axle to rotate along with the axle. Preferably, a retainer is provided to temporarily retain the first reel in the disconnected state. Preferably, a spring is provided to move the first reel towards the connected state upon release from the retainer. However, other elements urging the first reel towards the connected state and/or keep the first reel in the connected state may be provided, e.g. permanent magnets. 
     In an embodiment, the first reel has a coupling element and the axle has a coupling element to couple with the coupling element of the first reel in a connected state. Preferably, the coupling element of the first reel and the corresponding coupling element on the axle are configured such that the coupling is stronger in a rotational direction corresponding to paying out the first rope than in the opposite rotational direction. 
     In an embodiment, the second reel has a disconnected state, in which the axle is free to rotate relative to the second reel, and a connected state, in which the second reel is connected to the axle to rotate along with the axle. Preferably, a retainer is provided to temporarily retain the second reel in the disconnected state. Preferably, a spring is provided to move the second reel towards the connected state upon release from the retainer. However, other elements urging the second reel towards the connected state and/or keep the second reel in the connected state may be provided, e.g. permanent magnets. 
     In an embodiment, the retainer to temporarily retain the first or second reel in the disconnected state is releasable from the respective first or second reel by rotating the respect first or second reel over a predetermined angle, preferably smaller than 360 degrees, more preferably smaller than 180 degrees and most preferably smaller than 90 degrees, for instance smaller than 45 degrees, between a retaining orientation and a releasing orientation. For instance, in the retaining orientation, a shoulder may be present on the first or second reel to cooperate with a hook element on the retainer, while in the releasing orientation, no shoulder may be present for the retainer to cooperate with, thereby releasing the first or second reel. In between the retaining orientation and the releasing orientation, the should may gradually disappear. 
     In an embodiment, rotating the first or second reel causes a mechanism, e.g. a cam mechanism, or a simple cord or similar device, to operate on the retainer thereby moving the retainer to a releasing position in which the retainer is no longer connected to the first or second reel, thereby allowing the first or second reel to move to the connected state. 
     In an embodiment, the retainer has a predetermined strength and is connected between the first or second reel and another element of the device, e.g. a frame or the axle, such that when a predetermined load is applied to the first or second reel, the retainer is broken or damaged thereby releasing the first or second reel from the retainer or the other element of the device. 
     In an embodiment, the retainer is a permanent magnet cooperating with ferromagnetic material on the first or second reel. The other way around with the retainer being ferromagnetic material and the permanent magnet being provided on the first or second reel is also possible. Rotating the first or second reel relative to the retainer may then rotate the ferromagnetic material and the permanent magnet out of engagement thereby releasing the first or second reel from the retainer. 
     In an embodiment, the second reel has a coupling element and the axle has a coupling element to couple with the coupling element of the second reel in a connected state. Preferably, the coupling element of the second reel and the corresponding coupling element on the axle are configured such that the coupling is stronger in a rotational direction corresponding to paying out the second rope than in the opposite rotational direction, e.g. due to a sawtooth pattern on the coupling elements that mesh with each other. 
     In an embodiment, the rope-lowering device comprises a frame for supporting the other components of the rope-lowering device and to withstand the loads applied to the rope-lowering device during lowering of persons. The frame preferably includes two end members and one or more cross beams interconnecting the two end members. Further, the frame may include a brake housing to accommodate the brake, which brake housing may be connected to the one or more cross beams. Depending on the application, one or more reinforcement elements, e.g. rods, may be provided, for instance extending between the two end members and possibly connected to the brake housing as well or extending between an end member and the brake housing. 
     In an embodiment, the rope-lowering device further comprises a cover to limit access to the device, which cover is preferably configured to be supported by the frame. 
     In an embodiment, the device, e.g. the frame and/or cover, are provided with a fixation device to fix the device to a building or any other construction. 
     In an embodiment, the axle is rotatably supported by the two end members of the frame, preferably using corresponding bearings between the axle and the end members. 
     In an embodiment, the brake is configured to apply an increasing braking force with increasing speed, e.g. lowering speed of the first and/or second rope. 
     In an embodiment, the brake is a centrifugal brake, e.g. with a stationary part being connected to the frame, e.g. via the brake housing, and a moveable part being connected to the axle. 
     In an embodiment, the brake is or comprises a rotary damper in which energy is dissipated to limit the lowering speed to a safe range for a wide variety of persons. For instance, the rotary damper is a hydraulic damper, e.g. a hydraulic damper in which hydraulic fluid is forced through one or more orifices to provide sufficient resistance to rotational movement. Dissipation may also occur in the form of eddy currents or electrical dissipation in one or more resistors. 
     In an embodiment, the first and/or second reel are permanently connected or coupled to the axle, for instance by being integral with the axle or by being permanently in the connected state using the aforementioned coupling elements. An advantage of the earlier described coupling, preferably having a strong and weak coupling direction, is that the respective reel may still be allowed to slip in predetermined cases, for example when both ropes are wound on the respective reels and one of the rope and reel combination is used for a first lowering. The other rope and reel combination may then be allowed to slip to keep the rope and reel combination in place. 
     In an embodiment, the length of first rope and the length of second rope is at least 3 meters, preferably at least 5 meters, more preferably at least 10 meters and most preferably at least 25 meters. 
     In an embodiment, the brake is configured to limit the fall speed for a person weighing 80 kg to at most 30 km/h, preferably to at most 25 km/h, more preferably to at most 20 km/h, most preferably to at most 15 km/h, e.g. to at most 10 km/h. 
     The invention also relates to a method for lowering persons from a building or the like, wherein use is made of a rope-lowering device according to the invention, said method comprising the following steps:
         a. connecting a first person to the first rope;   b. lowering the first person;   c. disconnecting the first person from the first rope;   d. connecting a second person to the second rope;   e. lowering the second person; and   f. disconnecting the second person from the second rope,       

     wherein during step e. the first rope is automatically hauled in. 
     In an embodiment, the method further comprises the following steps:
         g. connecting a next person to the first or second rope previously hauled in;   h. lowering the next person; and   i. disconnecting the next person from said first or second rope,       

     wherein during step h. the other one of the first and second rope is automatically hauled in, and wherein preferably the steps g. to i. are repeated until all persons have been lowered that need to be lowered. 
     In an embodiment, the second reel of the rope-lowering device has a disconnected state, in which the axle is free to rotate relative to the second reel, and a connected state, in which the second reel is connected to the axle to rotate along with the axle, wherein prior to step a. the second reel is brought into the disconnected state, and wherein during step d. or e. the second reel is brought into the connected state. 
     In an embodiment, the first reel of the rope-lowering device has a disconnected state, in which the axle is free to rotate relative to the first reel, and a connected state, in which the first reel is connected to the axle to rotate along with the axle, wherein prior to step a. the first reel is brought into the disconnected state, and wherein during step a. or b. the first reel is brought into the connected state. 
     The invention further relates to a method for refurbishing a rope-lowering device according to the invention after being used, said method comprising the step of:
         a. winding the first and/or second rope on the respective first and/or second reel.       

     In an embodiment, the first reel of the rope-lowering device has a disconnected state, in which the axle is free to rotate relative to the first reel, and a connected state, in which the first reel is connected to the axle to rotate along with the axle, and wherein the method includes the step of:
         b. providing the first reel in the disconnected state.       

     In an embodiment, the second reel of the rope-lowering device has a disconnected state, in which the axle is free to rotate relative to the second reel, and a connected state, in which the second reel is connected to the axle to rotate along with the axle, and wherein the method includes the step of:
         c. providing the second reel in the disconnected state.       

     In an embodiment, the method includes the step of carrying out maintenance to the brake, e.g. by replacing worn parts or portions. 
     Although reference is made to the lowering of persons, it will be apparent that the same device and methods can be used to lower objects. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described in a non-limiting way with reference to the accompanying drawings in which like parts are indicated by like reference symbols, and in which: 
         FIG. 1  schematically depicts a perspective view of a rope-lowering device according to an embodiment of the invention; 
         FIG. 2  schematically depicts front view of the rope-lowering device of  FIG. 1 ; 
         FIG. 3  schematically depicts a top view of the rope-lowering device of  FIG. 1 ; 
         FIG. 4  schematically depicts a side view of the rope-lowering device of  FIG. 1 ; 
         FIG. 5  schematically depicts a cross-sectional view of the rope-lowering device of  FIG. 1  according to line A-A as shown in  FIG. 4 ; 
         FIG. 6  schematically depicts a perspective view of a first or second reel of the rope-lowering device of  FIG. 1 ; 
         FIG. 7  schematically depicts a perspective view of a locking ring of the rope-lowering device of  FIG. 1 ; 
         FIG. 8  schematically depicts a building equipped with a rope-lowering device according to the invention; 
         FIG. 9  schematically depicts the lowering of a first person from the building of  FIG. 8 ; 
         FIG. 10  schematically depicts the first person reaching the ground after being lowered from the building of  FIG. 8 ; 
         FIG. 11  schematically depicts the lowering of a second person from the building of  FIG. 8 ; 
         FIG. 12  schematically depicts the second person reaching the ground after being lowered from the building of  FIG. 8 ; 
         FIG. 13  schematically depicts a portion of a rope-lowering device according to another embodiment of the invention; and 
         FIG. 14  schematically depicts a retainer for the rope-lowering device of  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1-5  schematically depict a rope-lowering device  10  according to an embodiment of the invention.  FIGS. 1-4  depict a perspective view, a front view, a top view, and a side view of the rope-lowering device  10 , respectively. In  FIG. 4 , a line A-A is shown indicating a plane used for the cross-sectional view of the rope-lowering device  10  as shown in  FIG. 5 . 
     The rope-lowering device  10  is intended and suitable for lowering persons for instance from a building or the like, e.g. including ski lifts, wind turbines, towers, etc., in case of an emergency when other exits cannot be used, e.g. due to a fire, flood or obstructions. However, the rope-lowering device  10  can also be used in other applications such as for instance lowering people into a cave. 
     The rope-lowering device  10  includes a frame  20 , which frame  20  in this embodiment comprises:
         two end members  21 ,  22 ;   two cross beams  23 ,  24  interconnecting the two end members  21 ,  22 ;   a brake housing  25  connected to the two cross beams; and   a reinforcement rod  26  extending between the two end members  21 ,  22  and through the brake housing  25 .       

     The frame  20  is constructed to provide a rigid frame for supporting the other components of the rope-lowering device  10  that will be explained below and to withstand the loads applied to the rope-lowering device  10  during lowering of persons. The frame  20  is preferably also configured to support a cover (not shown), which cover is designed to shield the interior of the rope-lowering device  10  thereby e.g. preventing persons from entering the interior and interfere with or get stuck in moveable components of the device  10  and/or shield the interior from weather influences such as rain or dust. 
     The frame  20  and/or cover may further be equipped with a fixation device (not shown) to fix the device  10  to the building or any other construction. The fixation device may for instance be an eye or hook to cooperate with another hook. This allows to temporarily fix the device  10  to the building or other construction in case of an emergency only, but the fixation device may also provide for a more (semi-)permanent fixation to the building or other construction, so that the device  10  is ready to be used anytime. 
     Supported by the frame  20 , the rope-lowering device  10  comprises:
         an axle  30  arranged to rotate about its longitudinal axis  31 ;   a first reel  40 ;   a second reel  45 ;   a brake  50  connected to the axle  30  and to the brake housing  25 , which brake  50  is configured to provide a braking force to the axle  30  independent of a direction of rotation of the axle  30  about its longitudinal axis  31 ;   a first rope  60  connected to the first reel  40  to be suspended from the first reel  40 ; and   a second rope  70  connected to the second reel  45  to be suspended from the second reel  45 .       

     The first and second rope  60 ,  70  have only been depicted in  FIG. 5  in an initial state in which both ropes  60 ,  70  are wound on the respective reel  40 ,  45 . The first and second rope  60 ,  70  have been omitted from  FIGS. 1-4  for clarity reasons. 
     As can be clearly seen in  FIG. 5 , the axle  30  is rotatably supported by the two end members  21 ,  22  of the frame  20  via bearings  32 ,  33 . In this embodiment, the axle  30  has a constant cross-section over the entire length of the axle  30 , but this is not necessary per se. 
     The brake  50  in this embodiment a centrifugal brake, meaning that rotation of the axle connected to the brake will apply centrifugal forces to friction pads causing them to move outwards against a drum or housing to apply a braking force upon touching the drum or housing. An advantage of this type of brake is that the braking force is independent of the direction of rotation and the brake limits the rotational speed of the axle  30  so that the speed with which the persons are lowered is also limited ensuring a smooth landing. The drum or housing of the brake  50  is connected to the brake housing  25  of the frame using bolts  51  as shown in the figures, although not all bolts are indicated using reference numeral  51 . 
     Although in this embodiment, the brake  50  is a frictional brake using an explicit wear surface, it may also be another type of brake, including but not limited to a hydrodynamic brake using friction in a working fluid, a pumping brake using pumping losses for braking, or an electromagnetic brake, e.g. using electromagnetic induction or eddy currents. Further, the brake may be a rotary damper, e.g. a hydraulic damper in which vanes are rotated through the housing and hydraulic fluid is forced through orifices in the vanes or between the vanes and the housing to provide sufficient resistance and thus braking force. 
     The first and second reel  40 ,  45  can be permanently connected to the axle  30 . In an embodiment, the reels may be integral with the axle  30 , e.g. when a cylindrical portion is defined on the axle  30  to receive the first or second rope, for instance using two flanges on the axle  30 . However, in the embodiment of  FIGS. 1-5 , the first and second reel  40 ,  45  are connectable to the axle  30 , so that the first and second reel  40 ,  45  have a disconnected state in which the axle  30  is free to rotate relative to the respective reel and a connected state in which the axle  30  is connected to the respective reel such that the reel rotates along with the axle  30 . 
     The first reel  40  is depicted in more detail in  FIG. 6 , which  FIG. 6  is a perspective view of the first reel  40 . In this embodiment, the second reel has a similar construction as the first reel, so that everything that will be described below with respect to the first reel may similarly apply to the second reel. 
     The first reel  40  comprises a cylindrical body  41  having a bore  40   a  extending through the cylindrical body  41  to rotatably receive the axle  30 . A first flange  42  is provided at one end of the cylindrical body and a second flange  43  is provided at an opposite end of the cylindrical body to define a space in between the first and second flange  42 ,  43  to receive the first rope  60 . 
     At a side of the second flange  43  facing away from the first flange  42 , the first reel  40  is provided with a coupling element  44  allowing to couple with a similar coupling element  80  on the axle  30  as will be explained in more detail below. In  FIG. 6  only a small portion of the coupling element  44  is visible, but reference is made to  FIGS. 1 and 2  in which the coupling element  44  is better depicted. 
     As mentioned above, the coupling element  44  of the first reel  40  is configured to couple to a similar coupling element  80  on the axle  30 . The corresponding coupling element of the second reel  45  is configured to couple to a similar coupling element  85  on the axle  30 . The coupling element  80  is depicted in more detail in  FIG. 7  and includes a ring-shaped body  81  having a bore  81   a  extending therethrough for receiving the axle  30 . In this embodiment, a sidewall of the ring-shaped body  81  includes a hole  81   b  allowing to fix the coupling element  80  to the axle  30 , e.g. by introducing a pin or screw or bolt into the axle  30  via the hole  81   b.  Any other fixation possibilities are also envisaged. 
     The coupling element  80  comprises a sawtooth pattern  82  at one end of the coupling element  80  that matches a sawtooth pattern on the coupling element  44  of the first reel. The sawtooth pattern ensures that once the coupling elements  44  and  80  engage with each other, a coupling is established such that rotation of the coupling element  80  (due to rotation of the axle  30 ) will also cause rotation of the first reel  40 . The coupling element  85  for the second reel  45  is similar in design and function. 
     Due to the sawtooth pattern, the coupling between coupling element  44  and coupling element  80  in one rotational direction is stronger than in the other rotational direction. Preferably, the coupling is strong in the rotational direction corresponding to lowering a person, i.e. the rotational direction corresponding to paying out the first rope  60  so that the first reel is operatively connected to the brake  50  during lowering at all times. The weak connection is then preferably in the opposite rotational direction corresponding to hauling in the first rope, so that the first reel  40  is able to slip relative to the coupling element  80  when the load is above a predetermined value, thereby preventing a lowered person from inadvertently being lifted by the first reel and first rope when another person is lowered using the second reel and second rope, and/or preventing the first rope and possible a hook or attachment member connected to a free end of the first rope from damaging the rope-lowering device upon reaching the frame  20  when lowering of a person using the second rope and second reel continues as will be explained below in more detail. Again, the same applies to the coupling element  85  and the second reel  45 . 
     Referring back to  FIG. 6 , the first flange  42  of the first reel  40  includes rope connecting holes  42   b  and  42   c  allowing to connect a free end of the first rope  60  to the first reel  40 . The second reel  45  may have similar holes for connecting a free end of the second rope  70  to the second reel  45 . The other free ends of the first rope  60  and the second rope  70  may be connected to a hook or other attachment member allowing a person to be suspended from the first and second rope. Alternatively, or additionally, it is possible that a harness is connected to the first and/or second rope. Of course, other connection principles to connect a rope to the reel as known in the art may be contemplated. 
     In the  FIGS. 1-5 , the first and second reel  40 ,  45  are both shown in their disconnected state. In the disconnected state of the first and second reel  40 ,  45 , two elements may operate on the respective reels, namely a spring  90  and a retainer  95 . The retainer  95  for the first reel  40  and the retainer  95  for the second reel  45  are shown in the  FIGS. 1-3 . The spring  90  is only depicted for the second reel  45  and omitted for the first reel  40  to show the retainer  95  more clearly for the first reel  40 . 
     The spring  90  is provided between the brake housing  25  and the respective reel  40 ,  45  to urge the respective reel  40 ,  45  towards the respective coupling element  80 ,  85 . Hence, the spring  90  urges the respective reel towards the connected state. The retainer  95  is provided between the brake housing  25  and the respective reel and is configured to temporarily retain the respective reel  40 ,  45  in the disconnected state. To this end, the first flange  42  of the first reel  40  comprises an opening  42   a  allowing to receive the retainer  95 , which retainer includes a hook portion to engage with a shoulder in or at the opening  42   a  thereby being able to counteract the applied spring force of spring  90  and to retain the first reel. The second reel comprises a similar opening to cooperate with the other retainer  95 . 
     The opening  42   a  in the first flange  42  of the first reel  40  may allow to rotate the first reel at least over a predetermined distance while being retained by the retainer  95  in a rotational direction corresponding to paying out the first rope. When the first reel  40  is rotated over the predetermined distance, the opening  42   a  is then preferably configured to move the hook portion of the retainer  95  to a position in which it is able to pass the opening  42   a  thereby allowing to release the first reel  40  from the retainer  95  by rotating the first reel  40  resulting in the first reel  40  being moved towards the connected state by bringing the coupling element  44  in engagement with the coupling element  80  using the spring  90 . An advantage of the retainer  95  and the spring  90  is that the respective reel can be manually and automatically brought from the disconnected state to the connected state using passive elements. However, a solution in which active elements are used are of course also envisaged. The same applies of course for the second reel  45  and the spring  90  and the retainer  95  corresponding to the second reel  45 . 
     A method of use according to an embodiment of the invention and using the rope-lowering device  10  of  FIG. 1  will be described below by reference to the  FIGS. 8-12 . 
       FIG. 8  schematically depicts a building B with a window or balcony  100  and above the window or balcony  100  the rope-lowering device  10  of  FIG. 1 . For ease of reference, the description below will continue as if the building has a window  100 , but the skilled person will recognize that the same applies to a balcony  100 . 
     The rope-lowering device  10  has an initial configuration in which the first rope  60  is wound on the first reel  40  for the most part and in which the second rope  70  is wound on the second reel  45  for the most part with the first and second reel  40 ,  45  being both in the disconnected state. 
     In this embodiment, an attachment member  61  is connected to a free end of the first rope  60  and an attachment member  71  is connected to a free end of the second rope  70 . The attachment members  61  and  71  are preferably positioned such that in case of an emergency, an average adult, after opening the window or braking the glass of the window, is able to reach the attachment members  61 ,  71 , possibly after using an aid such as a step, stair, chair or table. 
     In case of an emergency, a person may reach out to one of the attachment members  61 ,  72  to connect himself to the first or second rope  60 ,  70 . During connecting of the person to the first or second rope, the respective rope may be paid out sufficiently to allow the release from the respective reel from the retainer  95  thereby bringing the respective reel in the connected state in which the respective reel is connected to the brake  50 . However, bringing the respective reel in the connected state may also happen during the first stage of lowering described below. 
       FIG. 9  schematically depicts the building B, the window  100 , the rope-lowering device  10  and a person P 1 . The person P 1  has connected himself or herself to the attachment member  61  of the first rope  60  and has jumped out of the window  100 . Gravitational forces acting on the person P 1  will let him fall towards the ground G as indicated by arrow A 1 , but as the first reel  40  has been brought to the connected state, the brake is able to apply braking forces to the first rope  60  via the axle  30 , the coupling element  80  and the first reel  40  that counteract the gravitational forces and limit the lowering speed of the person P 1 . 
     Because the second reel  45  is still in the disconnected state, the paying out of the first rope  60  and resulting rotation of the axle  30  does not affect the second reel  45  with the second rope  70 . 
       FIG. 10  schematically depicts the situation in which the first person P 1  has reached the ground G and has disconnected himself from the attachment member  61 . This allows a second person P 2  (see  FIG. 11 ) to connect himself to the attachment member  71 . Preferably, during connecting of the second person P 2  to the attachment member  71 , the second reel  45  is released from the retainer  95  and moved to the connected state in which the second reel  45  is connected to the brake  50 . In this situation, both the first reel  40  and the second reel  45  are connected to the brake  50 . 
       FIG. 11  schematically depicts the situation in which the second person P 2  is lowered to the ground as indicated by arrow A 2 . Due to the second rope  70  being connected to the brake  50  via the second reel  45 , the coupling element  85  and the axle  30 , the lowering speed of the second person P 2  is limited by the brake  50  similarly as described above when the first person P 1  was lowered to the ground G. 
     The rope-lowering device  10  is configured such that when both the first and second reels  40 ,  45  are connected to the axle  30 , paying out one of the first and second rope  60 ,  70  will automatically cause the other one of the first and second rope  60 ,  70  to be hauled in. Hence, in the situation depicted in  FIG. 11 , paying out the second rope  70  will automatically haul in the first rope  60  as indicated by arrow A 1 . When the second person P 2  reaches the ground G and disconnects himself from the attachment member  71 , the attachment member  61  has reached the window  100  allowing a next person to use the first rope  60  to be lowered to the ground G as shown in  FIG. 12 . Lowering of person can now be continued by alternatingly using the first rope  60  and the second rope  70  until everybody has been lowered to the ground G. 
     A building B may of course be equipped with a plurality of rope-lowering devices  10  in order to increase the lowering capacity or to lower person from a higher level. In an embodiment, a person may have to use a first rope-lowering device to lower himself from a window  100  to a platform or balcony in between the window  100  and the ground G and subsequently may have to use a second rope-lowering device to lower himself from said platform or balcony to the ground G. 
     The sawtooth pattern on the coupling elements  44 ,  80  and  85  as described above may be advantageous in the situation of  FIG. 10  when the second person P 2  jumps out of the window  100  before the first person P 1  was able to disconnect himself from the first rope  60 . Because of the sawtooth pattern having a weak rotational coupling and a strong rotational coupling in the opposite direction, the first person P 1  will not be lifted due to the lowering of the second person P 2  as a result of the weak rotational coupling allowing the weight of the first person P 1  to let the first reel  40  slip relative to the coupling element  80 . A similar advantage may occur in the situation depicted in  FIG. 12 , when the first rope  60  and the attachment member  61  reach the frame and/or cover of the rope-lowering device  10 . When the second person P 2  would continue to pay out the second rope, the attachment member  61  may be brought into engagement of the frame and/or cover of the rope-lowering device thereby damaging the rope-lowering device or bringing the first rope  60  and attachment member  61  out of reach of a next person. The weak coupling between first reel and coupling element  80  will allow the first reel to slip relative to the coupling element thereby keeping the first rope and attachment member  61  within reach of the next person and/or preventing damage to the rope-lowering device  10 . 
     Although the above embodiments describe the first and second reel  40 ,  45  to be moveable between a disconnected state and a connected state, the invention can also be carried out when the first and second reel  40 ,  45  only have a connected state, e.g. when they are connected using the sawtooth pattern having a strong and weak coupling in two opposite rotational directions. The second reel  45  may then slip relative to the coupling element  85  during the first lowering as depicted in  FIG. 9 . 
       FIG. 13  schematically depicts a rope-lowering device  10  according to another embodiment of the invention. The rope-lowering device  10  is similar to the embodiment described in  FIGS. 1-5 , but with a different principle of retaining a first or second reel in the disconnected state. 
       FIG. 13  depicts a brake housing  25 , a first reel  40 , and a spring  90  similar to the embodiment of  FIGS. 1-5 . Connected to the brake housing is a first member  96  and connected to the first reel  40  is a second member  97 . The first and second member  96 ,  97  are in alignment in  FIG. 13  and are in contact with each other or at least close to each other in a disconnected state of the first reel  40 . To keep the first and second member  96 ,  97  close to each other and thus the first reel  40  in the disconnected state, a retainer  95  is provided as shown in  FIG. 14 . 
     The retainer  95  comprises a first leg  95   a  to be received in the first member  96  and a second leg  95   b  to be received in the second member  97 , wherein the first leg  95   a  and the second leg  95   b  are connected to each other by bridging element  95   c.  Bridging element  95   c  not only holds the first leg  85   a  and the second leg  95   b  together, it also prevents the retainer  95  from falling from the first and/or second member  96 ,  97 . The retainer  95  is to be inserted from above into location P 95  as depicted in  FIG. 13 . 
     The retainer  95  will then prevent the spring  90  from pushing the first reel  40  into the connected state as described above in reference to  FIGS. 1-5 . To release the first reel  40  and allow the spring  90  to move the first reel  40  to the connected state, the retainer needs to be removed or broken, preferably at or near bridging element  95   c.    
     To remove the retainer  95 , the retainer  95  may be connected to a string that can be manually pulled to pull the retainer  95  away when needed. 
     Alternatively, or additionally, the retainer may be connected to the first rope would on the first reel  40 , so that paying out the first rope will automatically pull the retainer  95  away. 
     In an embodiment, the second member  97  is attached to the first reel  40  such that the first reel is able to rotate while the second member  97  is maintained in the relative position relative to the first member as shown in  FIG. 13  so that although the first reel  40  is rotating, the retainer  95  is still able to retain the first reel  40  in the disconnected state. This allows to remove the retainer  95  only after some significant rotation of the first reel  40 . 
     Alternatively, or additionally, the bridging element  95   c  may be dimensioned or designed such that a predetermined load to the first reel will break the retainer  95  in two pieces so that it is no longer able to counteract the spring force applied by the spring  90 . 
     The retainer  95  and the first and second members  96 ,  97  may be configured such that the retainer  95  is clamped relative to the first and second members  96 ,  97  so that a relatively small load or movement of the device will not easily move the retainer  95  causing an undesired release of the first reel  40 . 
     The above has been described by reference to the first reel, but alternatively or additionally, this may also apply in a similar way to a second reel. 
     Although not shown, two bars or rods may extend between the two end members of the frame, with the first and second rope extending in the slit formed in between the two bars or rods. This slit may additionally or alternatively be provided in the cover. The slit may prevent the free ends of the first and second rope from being pulled on the first or second reel, respectively, but may also limit movement of the first and second rope in a direction perpendicular to the two bars or rods i.e. the slit. Additional element may also be provided to limit movement of the first and second ropes in a direction parallel to the two bars or rods, i.e. the slot. 
     The invention may be summarized by the following clauses:
         1. A rope-lowering device ( 10 ) for lowering persons (P 1 , P 2 ) from a building (B) or the like, comprising:
           an axle ( 30 ) arranged to rotate about its longitudinal axis ( 31 );   a first reel ( 40 ) connected or connectable to the axle;   a second reel ( 45 ) connected or connectable to the axle;   a brake ( 50 ) connected to the axle, which brake is configured to provide a braking force to the axle independent of a direction of rotation;   a first rope ( 60 ) connected to the first reel to be suspended from the first reel; and   a second rope ( 70 ) connected to the second reel to be suspended from the second reel,   wherein the rope-lowering device is configured such that when both the first and second reels are connected to the axle, paying out one of the first and second rope will automatically cause the other one of the first and second rope to be hauled in.   
           2. A rope-lowering device according to clause 1, wherein the first reel has a disconnected state, in which the axle is free to rotate relative to the first reel, and a connected state, in which the first reel is connected to the axle to rotate along with the axle, wherein preferably a retainer ( 95 ) is provided to retain the first reel in the disconnected state, and wherein preferably a spring ( 90 ) is provided to move the first reel towards the connected state upon release from the retainer.   3. A rope-lowering device according to clause 2, wherein the first reel has a coupling element ( 44 ), wherein the axle has a coupling element ( 80 ) to couple with the coupling element of the first reel in the connected state, and wherein preferably the coupling element of the first reel and the corresponding coupling element on the axle are configured such that the coupling is stronger in a rotational direction corresponding to paying out the first rope than in the opposite rotational direction.   4. A rope-lowering device according to any of clauses 1-3, wherein the second reel has a disconnected state, in which the axle is free to rotate relative to the second reel, and a connected state, in which the second reel is connected to the axle to rotate along with the axle, wherein preferably a retainer ( 95 ) is provided to retain the second reel in the disconnected state, and wherein preferably a spring ( 90 ) is provided to move the second reel towards the connected state upon release from the retainer.   5. A rope-lowering device according to clause 4, wherein the second reel has a coupling element, wherein the axle has a coupling element ( 85 ) to couple with the coupling element of the second reel in the connected state, and wherein preferably the coupling element of the second reel and the corresponding coupling element on the axle are configured such that the coupling is stronger in a rotational direction corresponding to paying out the second rope than in the opposite rotational direction.   6. A method for lowering persons (P 1 , P 2 ) from a building (B) or the like, wherein use is made of a rope-lowering device ( 10 ) according to clause 1, said method comprising the following steps:
           a. connecting a first person (P 1 ) to the first rope ( 60 );   b. lowering the first person;   c. disconnecting the first person from the first rope;   d. connecting a second person (P 2 ) to the second rope ( 70 );   e. lowering the second person; and   f. disconnecting the second person from the second rope,   wherein during step e. the first rope is automatically hauled in.   
           7. A method according to clause 6, further comprising the following steps:
           g. connecting a next person to the first or second rope previously hauled in;   h. lowering the next person; and   i. disconnecting the next person from said first or second rope,   wherein during step h. the other one of the first and second rope is automatically hauled in, and wherein preferably the steps g. to i. are repeated until all persons have been lowered that need to be lowered.   
           8. A method according to clause 6 or 7, wherein use is made of a rope-lowering device according to clause 4, wherein prior to step a. the second reel is brought into the disconnected state, and wherein during step d. or e. the second reel is brought into the connected state.   9. A method according to clause 8, wherein use is made of a rope-lowering device according to clauses 2 and 4, wherein prior to step a. the first reel is brought into the disconnected state, and wherein during step a. or b. the first reel is brought into the connected state.   10. A method for refurbishing a rope-lowering device according to clause 1, said method comprising the step of winding the first and/or second rope on the respective first and/or second reel.   11. A method according to clause 10, wherein the rope-lowering device is a rope-lowering device according to clause 2, and wherein the method includes the step of providing the first reel in the disconnected state.   12. A method according to clause 10 or 11, wherein the rope-lowering device is a rope-lowering device according to clause 4, and wherein the method includes the step of providing the second reel in the disconnected state.