Patent Publication Number: US-9409042-B2

Title: Emergency escape device

Description:
FIELD OF THE INVENTION 
     The present invention relates to an emergency escape device and, more particularly, to an emergency escape device that can enable rapid escape of evacuees by ensuring that a descending unit installed in an escape hole of a fire evacuation area descends along a guide unit at a reduced speed when an emergency evacuation situation such as fire or the like occurs in a high-rise building. 
     BACKGROUND OF THE INVENTION 
     In general, a slow descending device is extensively used as an emergency escape device. A stairway or an elevator cannot be used when an emergency situation such as fire or the like occurs in a high-rise building such as an apartment, a hotel or a hospital. In order to cope with this situation, the slow descending device is installed in a window or a porch. The slow descending device is a safety escape mechanism designed to enable an evacuee to slowly descend along a descending rope by his or her weight. In other words, the slow descending device has been developed to enable safe escape of evacuees in the event that the evacuees cannot escape through a typical doorway due to fire and so forth. Evacuees of all ages and sexes can escape to the bottom floor of a high-rise building by getting on the slow descending device, fastening a seat belt and allowing the slow descending device to descend by the weight of the evacuees. 
     The conventional emergency escape device is used in the following manner. In the event of an emergency situation, an evacuee holds a slow descending device and a reel and moves toward a window or a porch. The evacuee fastens a clamp of the slow descending device to an anchor fixed to a building. After fastening a seat belt connected to one end of a rope, the evacuee throws the reel out of the building so that the rope wound on the reel can be unwound. In this state, the evacuee jumps down from a porch or a window. Since the rope is slowly unwound by the slow descending device, the evacuee hanging on the rope through the seat belt can slowly descend and can make a safe landing on the ground floor. 
     However, the conventional emergency escape device has a problem in that two or more evacuees cannot successively escape using the slow descending device installed in one escape space. If one of the evacuees uses the emergency escape device, the remaining evacuees have to wait until the seat belt comes back to the original position. This makes it difficult for the evacuees to successively and rapidly escape from a building. 
     In case of the conventional emergency escape device, a rope is used for an evacuee to descend from an upper stair to the ground floor. This poses a problem in that, under the influence of wind or for other causes, the evacuee may collide with a building wall, a signboard or a window frame and may get injured. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an emergency escape device that can enable safe and rapid escape of evacuees by ensuring that a descending unit installed in an escape hole of a fire evacuation area descends along a guide unit at a reduced speed when an emergency evacuation situation such as fire or the like occurs in a high-rise building. 
     Another object of the present invention is to provide an emergency escape device capable of enabling evacuees to successively and rapidly escape from a building by ensuring that a descending unit moved down along a guide unit can quickly come back to an original position. 
     In accordance with the present invention, there is provided an emergency escape device including: an escape hole cap fitted from above to an escape hole of a fire evacuation area of a high-rise building so as to cover an inner edge of the escape hole; a guide unit vertically installed to extend above and below the escape hole cap; a descending unit positioned below the escape hole cap and slidably attached to the guide unit in such a manner as to descend along the guide unit; a slowing unit configured to ensure that the descending unit descends along the guide unit at a reduced speed; and a returning unit for returning the descending unit descended along the guide unit to an original position. The emergency escape device may further include: a locking unit for keeping the descending unit against downward movement in an upper portion of the guide unit. 
     With the emergency escape device of the present invention, it is possible to enable rapid escape of evacuees by ensuring that a descending unit installed in an escape hole of a fire evacuation area descends along a guide unit at a reduced speed when an emergency evacuation situation such as fire or the like occurs in a high-rise building. 
     Moreover, the emergency escape device of the present invention enables evacuees to successively and rapidly escape from a building by ensuring that a descending unit moved down along a guide unit can quickly come back to the original position. 
     Inasmuch as the emergency escape device is permanently installed in a fire evacuation area of a building, it is possible for evacuees to rapidly and safely escape from the building in the event of an emergency situation without having to bring a separate emergency escape device to the fire evacuation area. 
     Since a spiral spring type winder is used as a returning unit for returning a descending unit to the original position, it is possible to reduce the manufacturing cost of the emergency escape device and to restrain generation of noises during the operation of the emergency escape device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view illustrating one example of a high-rise building to which an emergency escape device according to a first preferred embodiment of the present invention is applied. 
         FIG. 2  is a perspective view of the emergency escape device shown in  FIG. 1 . 
         FIG. 3  is an exploded perspective view of the emergency escape device shown in  FIG. 1 . 
         FIGS. 4, 5 and 6  are front, side and top transparent section views schematically illustrating the emergency escape device shown in  FIG. 1 . 
         FIGS. 7 and 8  are views illustrating an emergency escape operation performed by the emergency escape device shown in  FIG. 1 . 
         FIG. 9  is a view illustrating another example of a high-rise building to which the emergency escape device shown in  FIG. 1  is applied. 
         FIGS. 10 and 11  are side and top transparent section views schematically illustrating an emergency escape device according to a first modified example of the first preferred embodiment. 
         FIGS. 12 and 13  are front transparent section views schematically illustrating an emergency escape device according to a second modified example of the first preferred embodiment. 
         FIG. 14  is a view showing an emergency escape area to which an emergency escape device according to a second preferred embodiment of the present invention is applied. 
         FIG. 15  is a perspective view of the emergency escape device shown in  FIG. 14 . 
         FIG. 16  is an exploded perspective view of the emergency escape device shown in  FIG. 15 . 
         FIG. 17  is a side section view of the emergency escape device shown in  FIG. 15 . 
         FIGS. 18 and 19  are views illustrating an emergency escape operation performed by the emergency escape device shown in  FIG. 15 . 
         FIGS. 20 and 21  are views showing an emergency escape device according to a third preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Certain preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a view illustrating one example of a high-rise building to which an emergency escape device according to a first preferred embodiment of the present invention is applied.  FIG. 2  is a perspective view of the emergency escape device shown in  FIG. 1 .  FIG. 3  is an exploded perspective view of the emergency escape device shown in  FIG. 1 .  FIGS. 4, 5 and 6  are front, side and top transparent section views schematically illustrating the emergency escape device shown in  FIG. 1 . 
     As shown in  FIGS. 1 through 6 , the emergency escape device according to a first preferred embodiment of the present invention includes: an escape hole cap  110  fitted from above to an escape hole P of a fire evacuation area of a high-rise building so as to cover an inner edge of the escape hole P; a guide unit  120  vertically installed to extend above and below the escape hole cap  110 ; a descending unit  130  positioned below the escape hole cap  110  and slidably attached to the guide unit  120  in such a manner as to descend along the guide unit  120 ; a slowing unit  140  configured to ensure that the descending unit  130  descends along the guide unit  120  at a reduced speed; a returning unit  150  for returning the descending unit  130  descended along the guide unit  120  to an original position; and a locking unit  160  for keeping the descending unit  130  against downward movement in an upper portion of the guide unit  120 . 
     In this regard, the fire evacuation area is a safe evacuation area provided in, e.g., an inter-household balcony border of an apartment. The fire evacuation area has an escape hole P through which an upper story and a lower story communicate with each other so that an evacuee can escape from the upper story to the lower story through the escape hole P using the emergency escape device. 
     The escape hole cap  110  is fitted from above to the escape hole P formed in the floor surface of the fire evacuation area so as to cover an inner edge of the escape hole P. The escape hole cap  110  includes: an insertion body  111  having a length substantially equal to the thickness of a floor in which the escape hole P is formed; a flange  112  formed to protrude from an upper end of the insertion body  111  and supported by the floor surface around the escape hole P when the insertion body  111  is inserted into the escape hole P; a shock absorber (not shown) arranged on a lower surface of the flange  112  to absorb shocks applied to the escape hole cap  110 ; a slowing unit reception compartment  114  formed inside the insertion body  111  to receive the slowing unit  140 ; and a support bracket  115  attached to a partition wall defining the slowing unit reception compartment  114  and configured to vertically support the guide unit  120  positioned above and below the escape hole P. 
     In this regard, it is preferred that the slowing unit reception compartment  114  be closed by a panel or the like after the slowing unit  140  is received within the slowing unit reception compartment  114 . The support bracket  115  includes an anchor piece  115   a  fixed to the partition wall defining the slowing unit reception compartment  114 , a connector piece  115   b  bolted to the anchor piece  115   a  and a pair of upper and lower insertion pins  115   c  fixed to the connector piece  115   b  and fitted to the guide unit  120 . 
     With the escape hole cap  110  set forth above, the insertion body  111  is inserted from above to the escape hole P formed on the floor surface of a specific story. This helps prevent the body of an evacuee from being scratched by the edge of the escape hole P when the evacuee escapes through the use of the descending unit  130 . The shock absorber (not shown) of the escape hole cap  110  absorbs shocks applied to the escape hole cap  110  when another descending unit  130  descends from the upper story and makes contact with the escape hole cap  110 . This makes it possible to prevent occurrence of a safety accident. 
     The guide unit  120  is vertically installed above and below the escape hole cap  110  so that the descending unit  130  can safely descend and ascend along the guide unit  120 . The guide unit  120  includes a pair of guide frames  121  and  122  attached to the upper and lower insertion pins  115   c  of the support bracket  115 . Each of the guide frames  121  and  122  has a length substantially equal to the height of the fire evacuation area. 
     Prior to fitting each of the guide frames  121  and  122  to the upper insertion pin  115   c  of the support bracket  115 , a shock absorbing spring  123  and a sleeve  124  are fitted to the upper insertion pin  115   c  of the support bracket  115 . The shock absorbing spring  123  serves to absorb shocks applied to the descending unit  130  that descends along each of the guide frames  121  and  122 . The sleeve  124  is fixed to the upper end of the shock absorbing spring  123  and is configured to receive the lower end portion of each of the guide frames  121  and  122 . 
     With the guide unit  120  set forth above, the guide frames  121  and  122  are fitted to the upper and lower insertion pins  115   c  of the support bracket  115  of the escape hole cap  110 . The escape hole cap  110  is supported on the floor surface around the escape hole P. This makes it possible to keep the guide frames  121  and  122  stable when an evacuee escapes using the descending unit  130 . The guide frames  121  and  122  can be easily installed by merely fitting the guide frames  121  and  122  to the upper and lower insertion pins  115   c  of the support bracket  115 . 
     In this regard, each of the guide frames  121  and  122  has a length substantially equal to the distance between the escape hole caps  110  installed in the upper and lower stories of a building, i.e., the height of a specific story of the building. Since the guide frames  121  and  122  are removably attached to the upper and lower insertion pins  115   c  of the support bracket  115 , it becomes easy to perform a task of connecting the escape hole cap  110  and the guide frames  121  and  122 . 
     One of the guide frames  121  and  122  has an installation hole  125  formed in the uppermost portion thereof. The locking unit  160  is installed within the installation hole  125  so as to lock or release the descending unit  130 . 
     When the descending unit  130  descends toward the floor surface of the lower story, an evacuee can grip each of the guide frames  121  and  122 . This enables the evacuee to escape safely. It is preferred that the open space between the support bracket  115  and the guide frames  121  and  122  be closed by a decoration panel (not shown) so as to improve the external appearance of the escape hole cap  110  while interconnecting the guide frames  121  and  122 . 
     With the guide unit  120  set forth above, the descending unit  130  can move down along each of the guide frames  121  and  122  attached to the support bracket  115  of the escape hole cap  110  installed in the escape hole P. Therefore, unlike the conventional emergency escape device in which an evacuee escapes through the use of a rope, the descending unit  130  does not sway under the influence of wind. This makes it possible to prevent the evacuee from colliding with the objects on the outer wall of a building and eventually getting injured. 
     The descending unit  130  is mounted to the guide unit  120  so as to make contact with the lower end of the insertion body  111  of the escape hole cap  110  or the ceiling of a specific story having the escape hole P. The descending unit  130  is configured to descend along the guide unit  120 . The descending unit  130  includes: a descending panel  131  having a pair of through-holes  131   a  corresponding in shape to the guide frames  121  and  122  of the guide unit  120 ; a base frame  132  including a pair of embedment portions  132   a  embedded in the descending panel  131 , the base frame  132  having guide holes  132   b  formed in the embedment portions  132   a  in alignment with the through-holes  131   a  of the descending panel  131 , the guide frames  121  and  122  fitted to the guide holes  132   b  of the base frame  132 , the base frame  132  further including a connecting portion  132   c  connected to the slowing unit  140  and an open portion  132   d  defined between the embedment portions  132   a;  first and second guide rollers  133  and  134  rotatably attached to the embedment portions  132   a  so as to make rolling contact with the guide frames  121  and  122  inserted into the guide holes  132   b;  and a release button  135  provided in the descending panel  131  so as to release the locking unit  160  for having the descending panel  131  locked in an upper portion of one of the guide frames  121  and  122 . 
     Preferably, the descending panel  131  is a durable light panel having a specified thickness and an area larger than the escape hole P. The descending panel  131  is formed of an upper board, a lower board and a honeycomb-like intermediate board, which are bonded to each other or formed into one piece. If necessary, an auxiliary panel (not shown) corresponding in shape and size to the inner space of the insertion body  111  of the escape hole cap  110  may be attached to the upper surface of the descending panel  131 . 
     The first and second guide rollers  133  and  134  making rolling contact with the guide frames  121  and  122  are formed into a well-known shape and configuration so that the friction between the first and second guide rollers  133  and  134  and the guide frames  121  and  122  can be minimized. The first and second guide rollers  133  and  134  are preferably kept spaced apart from the guide frames  121  and  122  by a specified distance. 
     The release button  135  includes: a head  135   a  that can be pressed by the foot of an evacuee who gets on the descending panel  131  to escape to a lower story in the event of an emergency situation; a pressing shaft  135   b  extending from the head  135   a  to vertically penetrate the descending panel  131 , the pressing shaft  135   b  configured to, when the head  135   a  is pressed, move down and press a slant push-back portion  164  of the locking unit  160  so that a sliding body  162  of the locking unit  160  can be retracted into the installation hole  125  of one of the guide frames  121  and  122 ; and a biasing spring  135   c  arranged within the descending panel  131  to surround the pressing shaft  135   b,  the biasing spring  135   c  configured to bias the pressing shaft  135   b  upward. In this regard, an entrance hole  131   b  through which the sliding body  162  of the locking unit  160  can move is formed the side wall of the descending panel  131  near the release button  135 . 
     With the descending unit  130  configured as above, the descending panel  131  can descend along the guide frames  121  and  122  installed in the fire evacuation area of a high-rise building, whereby an evacuee can safely escape from an upper story to a lower story with no likelihood of collision with a building wall or the like. The slowing unit  140  serves to ensure that the descending unit  130  descends along the guide unit  120  at a reduced speed. The slowing unit  140  includes: a housing (not shown) arranged in the slowing unit reception compartment  114  formed inside the insertion body  111  of the escape hole cap  110 ; a large gear  143  rotatably installed within the housing and provided with a pulley  142 ; a small gear  145  rotatably installed within the housing to mesh with the large gear  143  and provided with a speed reducing wheel  144 ; a plurality of speed reducing pieces  146  radially arranged in the speed reducing wheel  144  to receive centrifugal forces; a speed reducing cover  147  fixed to the housing and arranged to surround the speed reducing wheel  144  and the speed reducing pieces  146 ; and a rope  148  wound around the pulley  142 , the rope  148  having a first end portion drawn out from a lower portion of the housing and fixed to the connecting portion  132   c  of the base frame  132  of the descending unit  130  and a second end portion drawn out from the lower portion of the housing and connected to a weight  151  of the returning unit  150  positioned near the guide frames  121  and  122 . 
     In this connection, the housing can be stably fixed to the escape hole cap  110  by a fastener (not shown). Preferably, the housing has a drawing-out hole (not shown) through which the first and second end portions of the rope  148  can be drawn out. 
     The large gear  143  is rotatably installed within the housing and is rotated by the frictional force of the rope  148  in the event of emergency evacuation. The large gear  143  is provided with a pulley  142  around which the rope  148  can be wound. The large gear  143  has a central shaft hole to which a shaft is fitted. Preferably, the pulley  142  is one-piece formed with the large gear  143 . 
     The small gear  145  is rotatably installed within the housing to mesh with the large gear  143  and is rotated by the large gear  143  in the event of emergency evacuation. The small gear  145  is provided with a speed reducing wheel  144  for applying brake to the large gear  143 . The speed reducing wheel  144  has a plurality of partition ribs  144   a  for isolating the speed reducing pieces  146  from one another. The small gear  145  has a central shaft hole to which a shaft is fitted. Preferably, the speed reducing wheel  144  is one-piece formed with the small gear  145 . 
     The speed reducing pieces  146  are radially arranged between the partition ribs  144   a  of the speed reducing wheel  144  to receive centrifugal forces. The speed reducing pieces  146  plays the role of a brake device when the descending unit  130  is moved down. During rotation of the speed reducing wheel  144 , the speed reducing pieces  146  are pushed radially outward by centrifugal forces to make frictional contact with the inner surface of the speed reducing cover  147 , thereby applying brake to the speed reducing wheel  144 . 
     The speed reducing cover  147  is arranged to surround the speed reducing wheel  144  and the speed reducing pieces  146 . The speed reducing cover  147  has central and lower shaft holes to which shafts are fitted. 
     In this regard, it is preferred that the large gear  143  and the small gear  145  have a gear ratio of about 3:1. This ensures that the small gear  145  meshing with the large gear  143  rotates faster than the large gear  143 , whereby speed reduction can be rapidly performed by the speed reducing pieces  146 . In order to make the internal space of the housing smaller, the large gear  143  and the small gear  145  are preferably formed of bevel gears, worm gears or helical gears. 
     If an evacuee gets on the descending unit  130  positioned just below the escape hole P of the fire evacuation area of a specified story and if the descending unit  130  is moved down by the weight of the evacuee, the slowing unit  140  allows the descending unit  130  to safely descend to a lower story along the guide frames  121  and  122  at a reduced speed under the braking action of the speed reducing pieces  146 . 
     The returning unit  150  serves to return the descended descending unit  130  to an original position. The returning unit  150  includes a weight  151  connected to the second end portion of the rope  148  drawn out from the housing of the slowing unit  140 . 
     In this regard, the weight  151  is a typical one and is preferably heavier than the descending unit  130  so that the descended descending unit  130  can readily ascend along the guide frames  121  and  122  when the evacuee gets off the descending unit  130 . 
     The weight  151  has a rod-like shape. The second end portion of the rope  148  is connected to the lower end portion of the weight  151 . As the descending unit  130  moves up and down, the weight  151  moves along one of guide holes  116  formed in the escape hole cap  110 . 
     The guide holes  116  are formed in a pair. The weight  151  existing in a specified story is moved through one of the guide holes  116 . The weight  151  existing in a story lower than the specified story is moved through the other guide hole  116 . Thus the weights  151  existing in different stories are prevented from colliding with each other during up-down movement thereof. 
     The returning unit  150  set forth above enables the descended descending unit  130  to quickly ascend to the original position along the guide frames  121  and  122  so that another evacuee can rapidly escape to a lower story. 
     The locking unit  160  serves to keep the descending unit  130  positioned in the upper portion of the guide unit  120 . The locking unit  160  includes: a casing  161  arranged in the installation hole  125  formed in the upper end portion of one of the guide frames  121  and  122 , the casing  161  having an opening formed on a side surface of the casing  161 ; a sliding body  162  retractably arranged within the casing  161 , the sliding body  162  including a support lug  163  and a slant push-back portion  164 , the support lug  163  obliquely formed in the sliding body  162  to extend out of the installation hole  125  through the opening of the casing  161  and configured to support a lower surface of the descending panel  131  of the descending unit  130  to thereby prevent the descending unit  130  from moving down, the slant push-back portion  164  obliquely formed at one side of the support lug  163  to extend out of the installation hole  125 , the slant push-back portion  164  configured to be pushed back into the casing  161  by means of the pressing shaft  135   b  of the release button  135  so that the support lug  163  can release the descending panel  131 ; and a return spring  165  arranged at the rear side of the sliding body  162  to bias the sliding body  162  outward so that the support lug  163  can protrude out of the installation hole  125  to support the descending panel  131  against downward movement. 
     In this regard, if the release button  135  is pressed down, the support lug  163  is moved inward to thereby allow the descending unit  130  to move down along the guide unit  120 . As the descending unit  130  descends from the locking unit  160 , the support lug  163  of the sliding body  162  is moved outward through the installation hole  125  under the action of the return spring  165 . 
     As the descended descending unit  130  is moved up along the guide unit  120  by means of the returning unit  150 , the support lug  163  is pressed by the descending panel  131  and is moved inward, thereby permitting upward movement of the descending unit  130 . As soon as the descending unit  130  ascends past the locking unit  160 , the support lug  163  is moved outward of the installation hole  125  by means of the return spring  165  so as to support the descending panel  131 . 
     With the locking unit  160  set forth above, if an evacuee gets on the descending panel  131  of the descending unit  130  and presses the release button  135 , the locking unit  160  releases the descending unit  130  so that the descending unit  130  can descend along the guide frames  121  and  122 . If the evacuee gets off the descending unit  130  at the end of descending movement, the descending unit  130  is moved up by the returning unit  150  and is supported again by the support lug  163 . In this state, the descending unit  130  is prevented from unexpectedly moving downward. This helps prevent occurrence of a safety accident. 
     In the emergency escape device according to the first embodiment of the present invention, the large gear  143  of the slowing unit  140  having the pulley  142  is rotated both when the descending unit  130  descends and when the descending unit  130  ascends. A ratchet mechanism (not shown) may be provided between the large gear  143  and the pulley  142  so that only the pulley  142  can rotate when the descending unit  130  is moved up along the guide frames  121  and  122  by means of the returning unit  150 . This enables the descending unit  130  to rapidly come back to the original position. 
     The emergency escape device according to the first embodiment of the present invention may further include a lighting unit (not shown) for lighting the fire evacuation area so that an evacuee can safely escape even in the event of electric outage. The lighting unit preferably includes a lamp arranged in the upper portion of each of the guide frames  121  and  122  and a power supply for supplying an electric current to the lamp. In this regard, the power supply may include a permanent magnet attached to the side surface of the large gear  143  or the small gear  145 , a coil arranged in a coil box spaced apart from the permanent magnet and an electric wire extending from a positive terminal of the coil to the lamp. As the permanent magnet rotates together with the large gear  143  or the small gear  145 , an electric current is generated in the coil and is supplied to the lamp. 
     In the emergency escape device according to the first embodiment of the present invention, the returning unit  150  is configured such that the descending unit  130  moved down along the guide unit  120  is returned to the original position by the weight  151  connected to the second end portion of the rope  148 . Instead of the weight  151 , a winder such as a spiral spring or a belt retractor may be connected to the second end portion of the rope  148  so that the rope  148  can be quickly rewound by the winder to return the descending unit  130  to the home position. In this case, one end of the rope  148  is preferably fixed to insertion body  111  of the escape hole cap  110  by way of a movable sheave so that the descending unit  130  can be moved up with a reduced force. 
     Next, description will be made on the operation of the emergency escape device according to the first embodiment of the present invention. 
       FIGS. 7 and 8  are views illustrating an emergency escape operation performed by the emergency escape device shown in  FIG. 1 . 
     As shown in  FIGS. 7 and 8 , the escape hole caps  110  are installed in the escape hole P of the ceiling of a specified story and in the escape hole P of the bottom of the specified story. The guide frames  121  and  122  of the guide unit  120  are fixed to the escape hole caps  110 . 
     The slowing unit  140  is installed in the slowing unit reception compartment  114  defined inside the insertion body  111  of the escape hole cap  110 . The descending panel  131  of the descending unit  130  and the weight  151  of the returning unit  150  are connected to the first and second end portions of the rope  148  of the slowing unit  140 . 
     Prior to attaching the guide frames  121  and  122  to the escape hole cap  110 , the guide frames  121  and  122  are inserted into the guide holes  131   a  of the descending panel  131  and the guide holes  132   b  of the base frame  132 . The first end portion of the rope  148  is connected to the connecting portion  132   c  of the base frame  132 . In this state, the unwinding length of the rope  148  connected to the weight  151  is adjusted so that the descending panel  131  can be supported by the support lug  163  of the sliding body  162  of the locking unit  160  installed in the installation hole  125  of one of the guide frames  121  and  122 . Thus the descending unit  130  is kept from moving down. 
     In the event of an emergency situation, an evacuee moves to the fire evacuation area and gets on the descending panel  131  of the descending unit  130  positioned just below the escape hole P of a specified story. 
     Then, if the evacuee presses the release button  135  with his or her foot, the support lug  163  of the locking unit  160  is retracted into the casing  161  of the locking unit  160 , thereby releasing the descending panel  131 . As a consequence, the descending unit  130  is moved down along the guide frames  121  and  122  of the guide unit  120 . 
     During the downward movement of the descending unit  130 , the weight  151  of the returning unit  150  is moved up through the guide hole  116  formed in the escape hole cap  110 . In response, the large gear  143  of the slowing unit  140  is rotated by the pulling force of the rope  148  connected to the descending panel  131  and the weight  151 . As the rotating speed of the large gear  143  is increased, the speed reducing pieces  146  arranged in the speed reducing wheel  144  of the small gear  144  meshing with the large gear  143  are displaced radially outward by the centrifugal force. Thus the speed reducing pieces  146  come into contact with the inner surface of the speed reducing cover  147 , thereby applying brake to the speed reducing wheel  144  so that the large gear  143  can rotate at a reduced speed. This makes it possible to keep the descending speed of the descending unit  130  substantially constant. The first and second guide rollers  133  and  134  attached to the base frame  132  of the descending unit  130  make rolling contact with the guide frames  121  and  122  during the downward movement of the descending unit  130 . This ensures that the descending unit  130  is smoothly moved down along the guide frames  121  and  122  with reduced frictional resistance. 
     The descending unit  130  continues to descend until the descending unit  130  comes into contact with the upper surface of the escape hole cap  110  installed in the escape hole P defined in the floor surface of a lower story. In this state, the evacuee gets off the descending unit  130 . If the weight of the evacuee is removed from the descending panel  131  of the descending unit  130 , the descending unit  130  is moved up along the guide frames  121  and  122  under the action of the weight  151  of the returning unit  150 . 
     At this time, the weight  151  of the returning unit  150  is moved down through the guide hole  116  of the escape hole cap  110 . In response, the descending unit  130  is moved up along the guide frames  121  and  122  by the distance corresponding to the descending distance of the weight  151 . 
     During the upward movement of the descending unit  130 , the large gear  143  is held against rotation by the ratchet mechanism (not shown) provided between the pulley  142  and the large gear  143  of the slowing unit  140 . Accordingly, the descending unit  130  is quickly moved up to the original position until the descending unit  130  comes into contact with the escape hole cap  110 . This assists in enabling another evacuee to rapidly escape to the lower story of a building. 
     Once the descending unit  130  moves up to the original position and makes contact with the escape hole cap  110  of the upper story, the support lug  163  of the locking unit  160  protrudes under the descending unit  130  and supports the descending unit  130  against downward movement until and unless the release button  135  is pressed again. 
       FIG. 9  is a view illustrating another example of a high-rise building to which the emergency escape device shown in  FIG. 1  is applied. 
     In the first preferred embodiment described above, only one escape hole P is formed in the fire evacuation area of each of the stories of a building. Alternatively, a plurality of escape holes P may be formed side by side in the fire evacuation area of each of the stories. 
       FIGS. 10 and 11  are side and top transparent section views schematically illustrating an emergency escape device according to a first modified example of the first preferred embodiment. 
     In the first preferred embodiment described above, the guide members  120  vertically extending from the upper and lower surfaces of the escape hole cap  110  are fixed to the support brackets  115  of the escape hole cap  110 . The descending unit  130  is installed to move up and down along the guide frames  121  and  122 . In the first modified example of the first preferred embodiment, as shown in  FIGS. 10 and 11 , a single guide frame  121  may be fixed to a single support bracket  115  provided in the escape hole cap  110 . In this case, the descending unit  130  can move up and down along the single guide frame  121 . Preferably, first, second, third and fourth guide rollers  133 ,  134 ,  136  and  137  are arranged at the front, rear, left and right sides of the guide frame  121  so as to make rolling contact with the guide frame  121 . 
     The first modified example of the first preferred embodiment remains the same as the first preferred embodiment except that the guide frame  121  is single. The configurations identical with or similar to those of the first preferred embodiment will not be described in detail 
     The weight  151  may not be a rod-like shape but may be a lump-like shape. A guide frame for guiding the weight  151  may be provided below the slowing unit reception compartment  114  to extend over an up-down movement range of the weight  151 . 
       FIGS. 12 and 13  are front transparent section views schematically illustrating an emergency escape device according to a second modified example of the first preferred embodiment. 
     In the first preferred embodiment described above, the slowing unit  140  for allowing the descending unit  130  to descend along the guide unit  120  at a reduced speed includes the ratchet mechanism (not shown) arranged between the large gear  143  and the pulley  142 . The ratchet mechanism enables the pulley  142  to rotate independently of the large gear  143  so that the descending unit  130  can be quickly moved up to the original position. 
     In the second modified example of the first preferred embodiment, as shown in  FIGS. 12 and 13 , the slowing unit  140  is not provided with any ratchet mechanism and is configured to enable the large gear  143  and the small gear  145  to mesh with each other only when the descending panel  131  is pressed by the foot of the evacuee. The slowing unit  140  further includes: a driven gear  149   a  arranged below the large gear  143  to mesh with the large gear  143 ; and a support piece  149   b  for interconnecting a shaft of the driven gear  149   a  and a shaft of the large gear  143  and supporting the shaft of the large gear  143 , the support piece  149   b  having a slot  149   c  into which the shaft of the large gear  143  is slidably inserted so that, when the descending panel  131  is pressed, the large gear  143  can move toward the small gear  145  and can mesh with the small gear  145 . The first end portion of the rope  148  is wound around the pulley  142  and fixed to a right portion of the descending panel  131 . The intermediate portion of the rope  148  is wound around a sheave  149   d  attached to the weight  151 . The second end portion of the rope  148  is wound around a pulley  149   e  arranged at one side of the large gear  143  and fixed to a left portion of the descending panel  131 . 
     In this regard, it is preferred that the weight  151  has a lump-like shape rather than a rod-like shape. The weight  151  is held by the intermediate portion of the rope  148  through the sheave  149   d  in such a way that the weight  151  is positioned near the lower end portion of the guide unit  120  when the descending unit  130  is supported by the support lug  163  of the locking unit  160  in the upper end portion of the guide unit  120  but the weight  151  is positioned near the upper end portion of the guide unit  120  when the descending unit  130  is moved down to the lower end portion of the guide unit  120 . 
     With the slowing unit  140  described above, if the evacuee gets on the descending panel  131  and presses the descending unit  130  with the foot of the evacuee in a state that the large gear  143  and the small gear  145  are spaced apart from each other, the rope  148  applies a rotating force to the large gear  143  in such a direction as to move the large gear  143  toward the small gear  145 . As a result, the shaft of the large gear  143  is moved toward the small gear  145  along the slot  149   c  of the support piece  149   b  so that the large gear  143  can mesh with the small gear  145 . Consequently, the small gear  145  provided with a speed reducing unit is rotated by the large gear  143 , thereby ensuring that the descending unit  130  descends along the guide unit  120  at a reduced speed. This makes it possible for the evacuee to safely escape to the lower story. 
     If the evacuee gets off the descending unit  130  and sets the descending unit  130  free in a state that the large gear  143  meshes with the small gear  145 , the rope  148  applies a rotating force to the large gear  143  in such a direction as to move the large gear  143  away from the small gear  145 . As a result, the shaft of the large gear  143  is moved toward the pulley  149   e  along the slot  149   c  of the support piece  149   b  so that the large gear  143  can disengage from the small gear  145 . Consequently, the small gear  145  provided with a speed reducing unit is not rotated. This enables the descending unit  130  to quickly ascend to the original position with no reduction in speed. 
     With the emergency escape device of the present invention described above, it is possible to enable safe and rapid escape of evacuees by ensuring that the descending unit installed in the escape hole of the fire evacuation area descends at a reduced speed along the guide unit vertically installed in the escape hole when an emergency evacuation situation such as fire or the like occurs in a high-rise building. 
     Moreover, the emergency escape device of the present invention enables evacuees to successively and rapidly escape from a building by ensuring that the descending unit moved down along the guide unit can quickly come back to the original position. 
     Inasmuch as the emergency escape device is permanently installed in the fire evacuation area of a building, it is possible for evacuees to rapidly and safely escape from the building in the event of an emergency situation without having to bring a separate emergency escape device to the fire evacuation area. 
     In the emergency escape device of the first preferred embodiment described above, the weight is employed as the returning unit for returning the descending unit moved down along the guide unit to the original position. Alternatively, the emergency escape devices according to second and third preferred embodiments of the present invention employ a spiral spring type winder as the returning unit for returning the descending unit moved down along the guide unit to the original position. This makes it possible to reduce the manufacturing cost of the emergency escape device and to restrain generation of noises during the operation of the emergency escape device. 
     Description will now be made on the emergency escape devices according to second and third preferred embodiments of the present invention. 
       FIG. 14  is a view showing an emergency escape area to which the emergency escape device according to the second preferred embodiment of the present invention is applied.  FIG. 15  is a perspective view of the emergency escape device shown in  FIG. 14 .  FIG. 16  is an exploded perspective view of the emergency escape device shown in  FIG. 15 .  FIG. 17  is a side section view of the emergency escape device shown in  FIG. 15 . 
     As shown in  FIGS. 14 through 17 , the emergency escape device according to the second preferred embodiment of the present invention includes: an escape hole cap  210  fitted from above to an escape hole P of a fire evacuation area of a high-rise building so as to cover an inner edge of the escape hole P; a guide unit  220  vertically installed below the escape hole cap  210 ; a descending unit  230  positioned below the escape hole cap  210  and slidably attached to the guide unit  220  in such a manner as to descend along the guide unit  220  when an evacuee gets on the descending unit  230 ; a slowing unit  240  configured to ensure that the descending unit  230  descends along the guide unit  220  at a reduced speed; a returning unit  250  for returning the descending unit  230  descended along the guide unit  220  to an original position; and a locking unit  260  for keeping the descending unit  230  against downward movement in an upper portion of the guide unit  220 . 
     In this regard, the fire evacuation area is a safe evacuation area provided in, e.g., an inter-household balcony border of an apartment. The fire evacuation area has an escape hole P through which an upper story and a lower story communicate with each other so that an evacuee can escape from the upper story to the lower story through the escape hole P using the emergency escape device. 
     The escape hole cap  210  is fitted from above to the escape hole P formed in the floor surface of the fire evacuation area so as to cover an inner edge of the escape hole P. The escape hole cap  210  includes: an insertion body  211  having a length substantially equal to the thickness of a floor in which the escape hole P is formed; a flange  212  formed to protrude from an upper end of the insertion body  211  and supported by the floor surface around the escape hole P when the insertion body  211  is inserted into the escape hole P; a shock absorber (not shown) arranged on a lower surface of the flange  212  to absorb shocks applied to the escape hole cap  210 ; and a support bracket  213  attached to a side surface of the insertion body  211  and configured to vertically support the guide unit  220  positioned below the escape hole P. 
     In case where an upper story and a lower story communicate with each other through the escape hole P, the guide units  220  may be vertically installed above and below the escape hole cap  210 . In this case, the guide units  220  are connected to upper and lower end portions of the support bracket  213 . 
     With the escape hole cap  110  set forth above, the insertion body  211  is inserted from above to the escape hole P formed on the floor surface of a specific story. This helps prevent the body of an evacuee from being scratched by the edge of the escape hole P when the evacuee escapes through the use of the descending unit  230 . The shock absorber (not shown) of the escape hole cap  210  absorbs shocks applied to the escape hole cap  210  when another descending unit  230  descends from the upper story and makes contact with the escape hole cap  210 . This makes it possible to prevent occurrence of a safety accident. 
     The guide unit  220  is vertically installed below the escape hole cap  210  (in case where the escape holes P of two upper and lower stories are formed out of alignment) or above and below the escape hole cap  210  (in case where the escape holes P of two upper and lower stories are aligned with each other) so that the descending unit  230  can safely descend and ascend along the guide unit  220 . The guide unit  220  includes a pair of guide frames  221  attached to the upper and lower portions of the support bracket  213 . Each of the guide frames  221  has a length substantially equal to the height of the fire evacuation area. 
     In case where the escape holes P of two upper and lower stories are aligned with each other, a shock absorbing spring  222  and a sleeve  223  are fitted to the upper end portion of the support bracket  213  prior to fitting each of the guide frames  221  to the upper end portion of the support bracket  213 . The shock absorbing spring  222  serves to absorb shocks applied to the descending unit  230  that descends along each of the guide frames  221 . The sleeve  223  is fixed to the upper end of the shock absorbing spring  222  and is configured to receive the lower end portion of each of the guide frames  221 . In case where the escape holes P of two upper and lower stories are formed out of alignment, a shock absorbing spring  222  and a sleeve  223  are fitted to the lower end portion of the guide unit  220 . 
     Each of the guide frames  221  has a length substantially equal to the distance between the escape hole caps  210  installed in the upper and lower stories of a building, i.e., the height of a specific story of the building. When the descending unit  130  descends toward the floor surface of the lower story, an evacuee can grip each of the guide frames  221 . This enables the evacuee to escape safely. An installation hole (not shown) is formed in the upper end portion of one of the guide frames  221 . The locking unit  260  for releasably locking the descending unit  230  is arranged in the installation hole. Each of the guide frames  221  may be directly fixed to the escape hole cap  210  by welding or other fixing methods. 
     While the guide frames  221  are provided in a pair in the illustrated example, it may be possible to a single guide frame. A decoration panel C is arranged between the guide frames  221 . The decoration panel C can provide a moving path of a chain  249  and a balancing weight (not shown) of the slowing unit  240  and can improve the external appearance of the emergency escape device. A single guide frame may be installed to extend along the decoration panel C. 
     With the guide unit  220  set forth above, the guide frames  221  are fitted to the upper and lower end portions of the support bracket  213  of the escape hole cap  210 . The escape hole cap  210  is supported on the floor surface or the ceiling surface around the escape hole P. This makes it possible to keep the guide frames  221  stable when an evacuee escapes using the descending unit  230 . The guide frames  221  can be easily installed by merely fitting the guide frames  221  to the upper and lower end portions of the support bracket  213 . 
     The descending unit  230  is mounted to the guide unit  220  at the lower side of the insertion body  211  of the escape hole cap  210 . The descending unit  230  is configured to descend along the guide unit  220 . The descending unit  230  includes: a descending panel  231  having a pair of cutouts corresponding in shape to the guide frames  221  of the guide unit  220 ; a base frame  232  including a pair of embedment portions embedded in the descending panel  231 , the base frame  232  having guide holes formed in the embedment portions in alignment with the cutouts of the descending panel  231 , the guide frames  221  fitted to the guide holes of the base frame  232 , the base frame  232  further including a connecting portion connected to a first end portion of a chain  249  of the slowing unit  240 ; first and second guide rollers  233  and  234  rotatably attached to the embedment portions so as to make rolling contact with the guide frames  221  inserted into the guide holes of the base frame  232 ; and a release button  235  provided in the descending panel  231  so as to release the locking unit  260  for having the descending panel  231  locked in an upper portion of one of the guide frames  221 . 
     Preferably, the descending panel  231  is formed of a durable light panel having a specified thickness and an area substantially equal to the area of the escape hole P. Although not shown in the drawings, it is preferred that a safety bar to be gripped by an evacuee is installed on the upper surface of the descending panel  231 . 
     The first and second guide rollers  233  and  234  making rolling contact with the guide frames  221  are formed into a well-known shape and configuration so that the friction between the first and second guide rollers  233  and  234  and the guide frames  221  can be minimized. The first and second guide rollers  233  and  234  are preferably kept spaced apart from the guide frames  221  by a specified distance so that the first and second guide rollers  233  and  234  make rolling contact with the guide frames  221  only when the descending panel  231  is tilted. This helps reduce friction and noises. 
     The release button  235  includes: a head  235   a  that can be pressed by the foot of an evacuee who gets on the descending panel  231  to escape to a lower story in the event of an emergency situation; a pressing shaft  235   b  extending from the head  235   a  to vertically penetrate the descending panel  231 , the pressing shaft  235   b  configured to, when the head  235   a  is pressed, move down and press a slant push-back portion  264  of the locking unit  260  so that a sliding body  262  of the locking unit  260  can be retracted into an installation hole of one of the guide frames  221 ; and a biasing spring  235   c  arranged within the descending panel  231  to surround the pressing shaft  235   b , the biasing spring  235   c  configured to bias the pressing shaft  235   b  upward. In this regard, an entrance hole through which the sliding body  262  of the locking unit  260  can move is formed the side wall of the descending panel  231  near the release button  235 . 
     In case where the decoration panel C is installed between the guide frames  221 , an installation hole may be formed in the decoration panel C. In this case, the release button  235  is arranged in a through-hole formed in the descending panel  231  in alignment with the installation hole of the decoration panel C. The locking unit  260  is installed in the installation hole of the decoration panel C. 
     In the event that the escape holes P of two upper and lower stories are formed out of alignment, a platform W having guard bars S is preferably arranged on the floor surface of the lower story so that the evacuee can safely get off the descending unit  230  moved down. 
     With the descending unit  230  configured as above, the descending panel  231  can descend along the guide frames  221  installed in the fire evacuation area of a high-rise building, whereby an evacuee can safely escape from an upper story to a lower story with no likelihood of collision with a building wall or the like. 
     The slowing unit  240  serves to ensure that the descending unit  230  descends along the guide unit  220  at a reduced speed. The slowing unit  240  includes: a module box B arranged on the flange  212  of the escape hole cap  210 ; a driving shaft  241  arranged within the module box B; a large gear  242  installed within the module box B and fixed to the driving shaft  241 ; a small gear  244  installed within the module box B and driven by the large gear  242 , the small gear  244  provided with a speed reducing wheel  243 ; an intermediate gear group  245  arranged between the large gear  242  and the small gear  244  to transfer rotation of the large gear  242  to the a small gear  244  at an increased gear ratio; a plurality of speed reducing pieces  246  radially arranged in the speed reducing wheel  243  to receive centrifugal forces; a speed reducing cover  247  fixed to the module box B and arranged to surround the speed reducing wheel  243  and the speed reducing pieces  246 ; a pulley  248  fixed to the driving shaft  241  to rotate together with the driving shaft  241 ; and a chain  249  wound around the pulley  248 , the chain  249  having a first end portion drawn out from a lower portion of the module box B and fixed to the connecting portion of the base frame  232  of the descending unit  230  and a second end portion fixed to the pulley  248 . 
     In this regard, the module box B may be provided at one side of the flange  212  of the escape hole cap  210 . In this case, the escape hole cap  210  has a through-hole through which the first end portion of the chain  249  to be fixed to the descending panel  231  of the descending unit  230  is drawn out. 
     The chain  249  may not be merely wound around the pulley  248  of the slowing unit  240  but may mesh with a sprocket formed in the pulley  248 . In this case, it is preferred that a balancing weight (not shown) be connected to the second end portion of the chain  249  opposite to the first end portion fixed to the descending panel  231 . 
     The large gear  242  is securely fixed to the driving shaft  241  and is rotationally driven by the driving shaft  241  which in turn is rotated by the pulley  248  or the returning unit  250  during emergency evacuation. 
     The small gear  244  is rotatably installed within the module box B so as to mesh with the large gear  242  through the gear group  245  and is rotated by the large gear  242 . The small gear  244  is provided with the speed reducing wheel  243  for applying brake to the large gear  242 . The speed reducing wheel  243  has a plurality of radially-extending partition ribs  243   a  for isolating the speed reducing pieces  246  from one another. 
     The speed reducing pieces  246  are radially arranged between the partition ribs  243   a  of the speed reducing wheel  243  to receive centrifugal forces. The speed reducing pieces  246  plays the role of a brake device when the descending unit  230  is moved down. During rotation of the speed reducing wheel  243 , the speed reducing pieces  246  are pushed radially outward by centrifugal forces to make frictional contact with the inner surface of the speed reducing cover  247 , thereby applying brake to the speed reducing wheel  243 . 
     The speed reducing cover  247  is arranged to surround the speed reducing wheel  243  and the speed reducing pieces  246 . The speed reducing cover  147  has central and lower shaft holes to which shafts are fitted. 
     The gear group  245  includes a plurality of gears arranged between the large gear  242  and the small gear  244  to change the gear ratio between the large gear  242  and the small gear  244  to, e.g., about 3:1. This ensures that the small gear  243  meshing with the large gear  242  rotates faster than the large gear  242 , whereby speed reduction can be rapidly performed by the speed reducing pieces  246 . 
     If an evacuee gets on the descending unit  230  positioned just below the escape hole P of the fire evacuation area of a specified story and if the descending unit  230  is moved down by the weight of the evacuee, the slowing unit  240  allows the descending unit  230  to safely descend to a lower story along the guide frames  221  at a reduced speed under the braking action of the speed reducing pieces  246 . 
     It is apparent that the slowing unit  240  may be formed of a well-known centrifugal brake or a magnetic brake instead of the components stated above. 
     The returning unit  250  serves to return the descended descending unit  230  to an original position. The returning unit  250  includes: a driving gear  241   a  fixed to one end of the driving shaft  241 ; a driven gear  251  meshing with the driving gear  241   a  and having a rotating shaft  253 ; a winder  252  having a spiral spring  252   a  connected to the driven gear  251 , the spiral spring  252   a  configured to be tightened as the driven gear  251  rotates in a first direction or to be loosened to rotate the driven gear  251  in a second direction. 
     The spiral spring  252   a  of the winder  252  has a first end portion connected to a casing of the winder  252  and a second end portion connected to the rotating shaft  253  of the driven gear  251 . The spiral spring  252   a  is completely loosened when the descending unit  230  is in a ready-to-descend uppermost position. The spiral spring  252   a  is gradually tightened as the descending unit  230  is moved down. The spiral spring  252   a  is completely tightened when the descending unit  230  is in a ready-to-ascend lowermost position. The spiral spring  252   a  is gradually loosened as the descending unit  230  is moved up. In other words, the spiral spring  252   a  is forcibly tightened as the descending unit  230  is moved down. The spiral spring  252   a  is self-loosened to lift up the descending unit  230  when an evacuee gets off the descending unit  230 . 
     The gear ratio between the driven gear  251  and the driving gear  241   a  is set substantially equal to or larger than 10:1. This ensures that the spiral spring  252   a  is slowly tightened when the rotating shaft  253  of the driven gear  251  connected to the spiral spring  252   a  is rotated by the driving shaft  241 . This also ensures that the spiral spring  252   a  is slowly loosened when the driving shaft  241  is rotated by the rotating shaft  253  of the driven gear  251 . It is therefore possible to reduce the volume of the spiral spring  252   a  and the winder  252 . 
     In this regard, the spiral spring  252   a  of the winder  252  has a restoring force a little larger than the weight of the descending unit  230 . This ensures that the spiral spring  252   a  is rapidly loosened when an evacuee gets on the descending unit  230  and the spiral spring  252   a  is rapidly tightened when the evacuee gets off the descending unit  230 . 
     With the returning unit  250  set forth above, the descending unit  230  moved down along the guide frames  221  can quickly ascend to the original position. This enables another evacuee to rapidly escape from an upper story to a lower story. 
     Since the winder  252  having the spiral spring  252   a  is used to return the descended descending unit  230  to the original position, it is possible to provide the returning unit  250  in a cost-effective manner without having to use an expensive weight. It is also possible to suppress generation of frictional noises. 
     The locking unit  260  serves to keep the descending unit  230  positioned in the upper portion of the guide unit  220 . The locking unit  260  includes: a casing  261  arranged in the installation hole formed in the upper end portion of one of the guide frames  221 , the casing  261  having an opening formed on a side surface of the casing  261 ; a sliding body  262  retractably arranged within the casing  261 , the sliding body  262  including a support lug  263  and a slant push-back portion  264 , the support lug  263  obliquely formed in the sliding body  262  to extend out of the installation hole through the opening of the casing  261  and configured to support a lower surface of the descending panel  231  of the descending unit  230  to thereby prevent the descending unit  230  from moving down, the slant push-back portion  264  obliquely formed at one side of the support lug  263  to extend out of the installation hole, the slant push-back portion  264  configured to be pushed back into the casing  261  by means of the pressing shaft  235   b  of the release button  235  so that the support lug  263  can release the descending panel  231 ; and a return spring  265  arranged at the rear side of the sliding body  262  to bias the sliding body  262  outward so that the support lug  263  can protrude out of the installation hole to support the descending panel  231  against downward movement. 
     In this regard, if the release button  235  is pressed down, the support lug  263  is moved inward to thereby allow the descending unit  230  to stably move down along the guide unit  220 . As the descending unit  230  descends from the locking unit  260 , the support lug  263  of the sliding body  262  is moved outward through the installation hole under the action of the return spring  265 . 
     As the descended descending unit  230  is moved up along the guide unit  220  by means of the returning unit  250 , the support lug  263  is pressed by the descending panel  231  and is moved inward, thereby permitting upward movement of the descending unit  230 . As soon as the descending unit  230  ascends past the locking unit  260 , the support lug  263  is moved outward of the installation hole by means of the return spring  265  so as to support the descending panel  231 . 
     In case where the decoration panel C is installed between the guide frames  221 , an installation hole may be formed in the decoration panel C. In this case, the release button  235  is arranged in a through-hole formed in the descending panel  231  in alignment with the installation hole of the decoration panel C. The locking unit  260  is installed in the installation hole of the decoration panel C. 
     With the locking unit  260  set forth above, if an evacuee gets on the descending panel  231  of the descending unit  230  and presses the release button  235 , the locking unit  260  releases the descending unit  230  so that the descending unit  230  can descend along the guide frames  221 . If the evacuee gets off the descending unit  230  at the end of descending movement, the descending unit  230  is moved up by the returning unit  250  and is supported again by the support lug  263 . In this state, the descending unit  230  is prevented from unexpectedly moving downward. This helps prevent occurrence of a safety accident. 
     In the emergency escape device according to the second embodiment of the present invention, the large gear  243  of the slowing unit  240  is rotated both when the descending unit  230  descends and when the descending unit  230  ascends. A ratchet mechanism (not shown) may be provided in the large gear  243  so that the descending unit  230  can rapidly come back to the original position. 
     Next, description will be made on the operation of the emergency escape device according to the second embodiment of the present invention. 
       FIGS. 18 and 19  are views illustrating an emergency escape operation performed by the emergency escape device shown in  FIG. 15 . 
     As shown in  FIGS. 18 and 19 , the escape hole cap  210  is installed in the escape hole P formed on the floor surface of a specified story. Then, the guide frames  221  of the guide unit  220  are fixed to the insertion body  211  of the escape hole cap  210 . Thereafter, the slowing unit  240  and the returning unit  250  are installed in the module box B arranged at one side of the escape hole cap  210 . The descending panel  231  of the descending unit  230  is connected to the chain  249  of the slowing unit  240 . 
     Prior to attaching the guide frames  221  to the escape hole cap  210 , the guide frames  221  are inserted into the guide holes  232   b  of the base frame  232 . The first end portion of the chain  249  is connected to the connecting portion  232   c  of the base frame  232 . In this state, the unwinding length of the chain  249  is adjusted so that the descending panel  231  can be supported by the support lug  263  of the sliding body  262  of the locking unit  260  installed in the installation hole of one of the guide frames  221 . Thus the descending unit  230  is kept from moving down. 
     In the event of an emergency situation such as fire or the like, an evacuee moves to the fire evacuation area and gets on the descending panel  231  of the descending unit  230  positioned just below the escape hole P of a specified story. 
     Then, if the evacuee presses the release button  235  with his or her foot, the support lug  263  of the locking unit  260  is retracted into the casing of the locking unit  260 , thereby releasing the descending panel  231 . As a consequence, the descending unit  230  is moved down along the guide frames  221  of the guide unit  220 . 
     At this time, the driving shaft  241  connected to the descending panel  231  through the chain  249  is rotated in one direction so that the spiral spring  252   a  of the winder  252  of the returning unit  250  can be gradually tightened. The large gear  242  is also rotated as the descending unit  230  is moved down. 
     As the rotating speed of the large gear  242  is increased, the speed reducing pieces  246  arranged in the speed reducing wheel  243  of the small gear  244  meshing with the large gear  242  are displaced radially outward by the centrifugal force. Thus the speed reducing pieces  246  come into contact with the inner surface of the speed reducing cover  247 , thereby applying brake to the speed reducing wheel  243  so that the driving shaft  241  and the pulley  248  can rotate at a reduced speed. This makes it possible to keep the descending speed of the descending unit  230  substantially constant. 
     The first and second guide rollers  233  and  234  rotatably attached to the base frame  232  of the descending unit  230  make rolling contact with the guide frames  221  during the downward movement of the descending unit  230 . This ensures that the descending unit  230  is smoothly moved down along the guide frames  221  with reduced frictional resistance. 
     If the evacuee gets off the descending unit  230  after the descending unit  230  is moved down to the platform W arranged on the floor surface of a lower story, the weight of the evacuee is removed from the descending unit  230 . Thus the descending unit  230  is moved up along the guide frames  221  under the action of the returning unit  250 . 
     At this time, the driving shaft  241  is rotated in the opposite direction so that the spiral spring  252   a  of the winder  252  of the returning unit  250  can be gradually loosened. Consequently, the descending unit  230  connected to the driving shaft  241  through the chain  249  is moved up by the restoring force of the spiral spring  252   a.    
     When the driving shaft  241  is rotated in the opposite direction, the ratchet mechanism (not shown) prevents rotation of the large gear  242 . Therefore, the small gear  244  does not reduce the rotating speed of the driving shaft  241 . As a consequence, the descending unit  230  is quickly moved up to the original position, thereby enabling another evacuee to escape from an upper story to a lower story. 
     Once the descending unit  230  moves up to the original position and makes contact with the escape hole cap  210  of the upper story, the support lug  263  of the locking unit  260  protrudes under the descending unit  230  and supports the descending unit  230  against downward movement until and unless the release button  235  is pressed again. 
     In the emergency escape device according to the second preferred embodiment of the present invention, the module box B accommodating the slowing unit  240  and the returning unit  250  is arranged at one side of the escape hole cap  210 . In case where the escape holes P of two upper and lower stories are formed out of alignment, the module box B accommodating the slowing unit  240  and the returning unit  250  may be provided within the platform W arranged on the floor surface of the lower story. In this case, the escape hole cap  210  may be provided with a pulley (not shown) around which the chain  249  of the slowing unit  240  is wound. The first end portion of the chain  249  is fixed to the pulley  248  of the slowing unit  240  while the second end portion of the chain  249  is fixed to the descending unit  230 . 
       FIGS. 20 and 21  are views showing an emergency escape device according to a third preferred embodiment of the present invention. 
     As shown in  FIGS. 20 and 21 , the emergency escape device according to the third preferred embodiment includes: an escape hole cap  210  fitted from above to an escape hole P of a fire evacuation area of a high-rise building so as to cover an inner edge of the escape hole P; a guide unit  220  vertically installed to extend downward from the escape hole cap  210 ; a descending unit  230  positioned below the escape hole cap  210  and movably attached to the guide unit  220  in such a manner as to descend along the guide unit  220 ; a slowing unit  240  configured to ensure that the descending unit  230  descends along the guide unit  220  at a reduced speed; a returning unit  250  for returning the descending unit  230  descended along the guide unit  220  to an original position; and a locking unit  260  for keeping the descending unit  230  against downward movement in an upper portion of the guide unit  220 . The guide unit  220  includes a ball screw  221   a  having upper and lower end portions rotatably attached to the escape hole cap  210  and a floor surface through bearings  221   b . The descending unit  230  includes a movable block G threadedly coupled to the ball screw  221   a  so that the descending unit  230  can move up and down as the ball screw  221   a  rotates. The slowing unit  240  includes a driving shaft  241  operatively connected to one end of the ball screw  221   a  through a well-known power transmission mechanism (e.g., helical gears or worm gears). 
     In this regard, the movable block G and the descending unit  230  are moved up and down depending on the rotating direction of the ball screw  221   a . During the downward movement of the descending unit  230 , the ball screw  221   a  is rotated by the weight of an evacuee getting on the descending unit  230 . During the upward movement of the descending unit  230 , the ball screw  221   a  is rotated by the loosening operation of the spiral spring  252   a  and the resultant rotation of the driving shaft  241  operatively connected to the ball screw  221   a.    
     During the upward and downward movement of the descending unit  230 , only the ball screw  221   a  is rotated and the descending unit  230  is prevented from rotation. In other words, the descending unit  230  is not rotated during the upward and downward movement thereof. 
     The emergency escape device according to the third preferred embodiment remains the same as the emergency escape device according to the first preferred embodiment except the configurations described above. 
     In the emergency escape device according to the third preferred embodiment, the module box B accommodating the slowing unit  240  and the returning unit  250  may be provided within the platform W arranged on the floor surface of the lower story. 
     In order to prevent occurrence of a safety accident attributable to the rotation of the ball screw  221   a , it is preferable to additionally install a sheath for surrounding the ball screw  221   a . In this case, the sheath needs to have a slot along which the movable block G can move. 
     Description will now be made on the operation of the emergency escape device according to the third preferred embodiment. If an evacuee gets on the descending unit  230  and if the locking unit  260  releases the descending unit  230 , the movable block G and the descending unit  230  are moved down by the weight of the evacuee while rotating the ball screw  221   a.    
     As the descending unit  230  is moved down, the spiral spring  252   a  of the winder  252  of the returning unit  250  is tightened by the rotation of the driving shaft  241  operatively connected to the ball screw  221   a.    
     If the rotating speed of the large gear  242  is increased during the downward movement of the descending unit  230 , the speed reducing pieces  246  arranged in the speed reducing wheel  243  of the small gear  244  meshing with the large gear  242  are displaced radially outward by the centrifugal force. Thus the speed reducing pieces  246  come into contact with the inner surface of the speed reducing cover  247 , thereby applying brake to the speed reducing wheel  243  so that the large gear  242  can rotate at a reduced speed. This makes it possible to keep the descending speed of the descending unit  230  substantially constant. 
     Thereafter, if the evacuee gets off the descending unit  230  moved down to the platform W arranged on the floor surface of a lower story, the weight of the evacuee is removed from the descending unit  230 . Thus the descending unit  230  is moved up under the action of the returning unit  250 . 
     At this time, the driving shaft  241  is rotated in the opposite direction so that the spiral spring  252   a  of the winder  252  of the returning unit  250  can be gradually loosened. Consequently, the ball screw  221   a  connected to the driving shaft  241  is rotated, thereby causing the descending unit  230  to move up. In other words, the ball screw  221   a  is rotated by the restoring force of the spiral spring  252   a , as a result of which the descending unit  230  is moved up. 
     When the driving shaft  241  is rotated in the opposite direction, the ratchet mechanism (not shown) prevents rotation of the large gear  242 . Therefore, the small gear  244  does not reduce the rotating speed of the driving shaft  241 . As a consequence, the descending unit  230  is quickly moved up to the original position, thereby enabling another evacuee to escape from an upper story to a lower story. 
     In the emergency escape devices according to the second and third preferred embodiments, the pulley  248  may be formed into a conical shape to have a small-diameter tip portion and a large-diameter base portion. The first end portion of the chain  249  or the rope wound around the tip portion of the pulley  248  is connected to the descending unit  230 . The second end portion of the chain  249  or the rope wound around the base portion of the pulley  248  is fixed to the pulley  248 . 
     During the downward movement of the descending unit  230 , the chain  249  is initially unwound from the small-diameter tip portion, thereby preventing the chain  249  from being unwound at an unduly high speed. During the upward movement of the descending unit  230 , the chain  249  is initially wound around the large-diameter base portion, thereby enabling the chain  249  to be wound at an increased speed. 
     With the emergency escape device of the present invention, it is possible to enable rapid escape of evacuees by ensuring that the descending unit installed in the escape hole of the fire evacuation area descends at a reduced speed along the guide unit at a reduced speed when an emergency evacuation situation such as fire or the like occurs in a high-rise building. 
     Moreover, the emergency escape device of the present invention enables evacuees to successively and rapidly escape from a building by ensuring that the descending unit moved down along the guide unit can quickly come back to the original position. 
     Inasmuch as the emergency escape device is permanently installed in the fire evacuation area of a building, it is possible for evacuees to rapidly and safely escape from the building in the event of an emergency situation without having to bring a separate emergency escape device to the fire evacuation area. Since the spiral spring type winder is used as the returning unit for returning the descending unit to the original position, it is possible to reduce the manufacturing cost of the emergency escape device and to restrain generation of noises during the operation of the emergency escape device.