Abstract:
The present invention provides a system and device for descending stairs. In one embodiment, the invention provides a system for transporting an individual down a flight of stairs, including means for directing at least one seat member selected from a group consisting of: a track adapted to accept at least one wheeled member of the at least one seat member and a cable adapted to support a clamp member secured to the at least one seat member.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Technical Field  
         [0002]     The invention relates generally to devices for descending stairs, and more particularly, to a gravity-powered system and device for transporting a disabled individual down a flight of stairs.  
         [0003]     2. Background Art  
         [0004]     In the event of an emergency, it is often necessary to evacuate residential and commercial buildings. Often, such buildings comprise more than one story or level. Due to the nature of an emergency evacuation (e.g., fire, power loss, etc.), it is inadvisable for an individual to use an elevator in making his or her evacuation. As such, the only other evacuation routes typically available include stairways and/or stairwells.  
         [0005]     Physically disabled individuals, whether previously disabled or injured as a result of the emergency prompting the evacuation, are often unable to utilize stairways or stairwells in making their evacuation. As a consequence, such individuals must either be aided in their descent of the stairway or stairwell by a non-disabled individual or await assistance from rescue personnel. This is problematic, as it jeopardizes not only the disabled individual but those aiding their evacuation and those hindered from making their own evacuations.  
         [0006]     A number of systems and devices have been proposed for the transportation of disabled individuals in emergency situations. For example, U.S. Pat. No. 5,539,945 to Rosenberg et al. discloses a stretcher device that can be supported at one end by a cable secured to a stairwell. However, the occupant of the stretcher must be secured in the stretcher by a rescuer and then carried down the stairway by at least one such rescuer.  
         [0007]     U.S. Pat. No. 4,963,762 to Brooks discloses an evacuation chair comprising a seat supported by two elongated poles, each pole having a handle on each end. An individual may thereby by carried down a flight of stairs by a pair of rescuers, each holding an end of each of the two poles. Thus, transportation of the individual requires the aid of at least two rescuers. U.S. Pat. No. 5,466,040 to Fainsztein describes a device similar to that of Brooks, wherein the ends of the poles are supported by a harness worn by each of the rescuers, thereby keeping the hands of the rescuers free.  
         [0008]     While each of the devices above enables the evacuation of a disabled individual with greater ease than merely carrying the individual down a flight of stairs, each is similarly unsatisfactory because of their reliance on the aid of at least one rescuer; often at least two rescuers.  
         [0009]     To this extent, a need exists for a system and device for descending stairs that do not suffer from the defects of known systems and devices.  
       SUMMARY OF THE INVENTION  
       [0010]     The present invention provides a system and device for descending stairs. In one embodiment, the invention provides a system for transporting an individual down a flight of stairs, including means for directing at least one seat member selected from a group consisting of: a track adapted to accept at least one wheeled member of the at least one seat member and a cable adapted to support a clamp member secured to the at least one seat member.  
         [0011]     A first aspect of the invention provides a device for transporting an individual down a flight of stairs comprising: a seat member adapted to support an individual; at least one wheeled member adapted to follow a track adjacent a flight of stairs; and a brake member adapted to control a rate of descent of the device along the track.  
         [0012]     A second aspect of the invention provides a device for transporting an individual down a flight of stairs comprising: a seat member adapted to support an individual; at least one clamp member adapted to follow a cable adjacent a flight of stairs; and a brake member adapted to control a rate of descent of the device along the track.  
         [0013]     A third aspect of the invention provides a system for transporting an individual down a flight of stairs comprising: at least one seat member adapted to support an individual; means for directing the at least one seat member along a path adjacent a flight of stairs; and a brake member for controlling a rate of descent of the at least one seat member along the path.  
         [0014]     The illustrative aspects of the present invention are designed to solve the problems herein described and other problems not discussed, which are discoverable by a skilled artisan.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     These and other features of this invention will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings that depict various embodiments of the invention, in which:  
         [0016]     FIGS.  1 A-D show various views of an illustrative rescue chair according to the invention.  
         [0017]      FIG. 2  shows an illustrative braking mechanism according to the invention.  
         [0018]      FIG. 3  shows a system comprising the rescue chair of FIGS.  1 A-D in conjunction with a pair of track members according to the invention.  
         [0019]     FIGS.  4 A-B show detailed views of the use of a track member of  FIG. 3 .  
         [0020]     FIGS.  5 A-B show an anti-collision device according to the invention.  
         [0021]     FIGS.  6 A-B show side and top cross-sectional views of a friction member for slowing a rescue chair according to the invention.  
         [0022]     FIGS.  7 A-B show an illustrative adjustable track according to the invention.  
         [0023]     FIGS.  8 A-B show an alternative system comprising the rescue chair of FIGS.  1 A-D in conjunction with a cable according to the invention.  
         [0024]     It is noted that the drawings of the invention are not to scale. The drawings are intended to depict only typical aspects of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements between the drawings.  
     
    
     DETAILED DESCRIPTION  
       [0025]     As indicated above, the invention provides a system and device for descending stairs.  
         [0026]     FIGS.  1 A-D show various views of an illustrative rescue chair  100  according to the invention.  FIG. 1A  shows a front perspective view of the rescue chair  100  comprising a seat  110  having a back portion  112  and bottom portion  114 , a pair of supports  120 ,  122  supporting the bottom portion  114  to the back portion  112 , and a brake handle  130 . Preferably, back portion  112  and bottom portion  114  are hingedly connected, permitting the folding of bottom portion  114  against back portion  112  when rescue chair  100  is not in use. Rescue chair  100  may further include a safety belt  126  of other device for securing a user within the chair.  
         [0027]      FIG. 1B  shows a side view of rescue chair  100  and the pivotal movement of bottom portion  114  at hinge  116  and along path A to position  114 ′ (shown in phantom). Also shown are wheeled members  140 ,  144 , each secured to back portion  112  by posts  141 ,  145 , respectively. Wheeled members  140 ,  144  are adapted to be inserted into a track, as will be described in greater detail below. Rescue chair  100  includes at least one wheeled member, preferably at least two wheeled members, one located vertically above the other, and more preferably four wheeled members arranged in two pairs, one pair located vertically above the other pair.  
         [0028]      FIG. 1C  shows a top view of rescue chair  100 , including the location of an additional wheeled member  142 .  FIG. 1C  also shows the connection of brake arm  130  to brake shaft  132 , which will be described in greater detail below.  
         [0029]      FIG. 1D  shows a rear view of rescue chair  100 . As shown in  FIG. 1D , rescue chair  100  includes four wheeled members  140 ,  142 ,  144 ,  146  arranged in two pairs ( 140  and  142  being located vertically above  144  and  146 , respectively). As will be described in greater detail below, at least two of the four wheeled members are adapted to be inserted into a track (not shown) secured to a railing or wall adjacent a stairway. As such, the wheeled members comprising each pair of wheeled members (i.e.,  140  and  142 ,  144  and  146 ) are offset from each other at angle α in order to accommodate the pitch of the track and the stairway.  
         [0030]     Still referring to  FIG. 1D , brake shaft  132  is shown comprising a pair of brake rods  134 ,  136 , each adapted to alternately move toward and away from wheeled members  140  and  144 , respectively, preventing or impeding the movement of wheeled members  140 ,  144  along the track, thereby stopping or slowing the descent of rescue chair  100 .  
         [0031]      FIG. 2  shows a detailed view of the braking mechanism of  FIG. 1D . Upon the downward movement of brake arm  130  along path B, a rotational movement along path C is imparted to brake shaft  132 . A corresponding upward movement along path D is imparted to brake rod  134 . An analogous downward movement would be imparted to brake rod  136  ( FIG. 1D ), which is attached to a surface of brake shaft  132  opposite that of brake rod  134 . Movement of brake rod  134  along path D sends brake rod  134  toward wheeled member  140  to position  134 ′ (shown in phantom). As shown in  FIG. 2 , brake rod  134  is fitted with a brake shoe  138  shaped to correspond to the shape of wheeled member  140 . Upon movement of brake rod  134  along path D, brake shoe  138  moves to position  138 ′, contacting wheeled member  140 , preventing or impeding its movement. As will be recognized by one skilled in the art, the braking mechanism of  FIG. 2  is merely illustrative of the braking mechanisms that may be employed and is in no way intended to limit the scope of the invention. For example, brake rod  134  may be adapted to fit within a corresponding slot (not shown) within a track (described below), thereby preventing the descent of rescue chair  100  (FIGS.  1 A-D).  
         [0032]     Referring now to  FIG. 3 , a rescue chair  100  according to the invention is shown in conjunction with a pair of track members  330 ,  332  secured to a railing  300  adjacent a flight of stairs  200 . Railing  300  includes angled handrails  310 ,  312  supported by a plurality of vertical columns  320 ,  322 . Handrails  310 ,  312  are angled (i.e., angle α) relative to horizontal in order to follow the descent of the flight of stairs  200 . As will be described in greater detail below, a pair of track members  330 ,  332  vertically disposed relative to each other, as shown in  FIG. 3 , is preferred in practicing the invention. Other configurations and arrangements are possible, however, as will be recognized by one skilled in the art.  
         [0033]     FIGS.  4 A-B show cross-sectional views of the placement of a wheeled member  140  into track member  330 . In  FIG. 4A , back portion  112  is angled (i.e., angle β) relative to vertical and moved along path G, such that wheeled member  140  passes into slot  331  of track member  330 . Once wheeled member  140  is inserted fully into slot  331 , back portion  112  is moved to the substantially vertical orientation of  FIG. 4B , such that wheeled member  140  rests against and within track member  330 . The connection of wheeled member  140  and track member  330  in the manner shown in FIGS.  4 A-B prevents the accidental removal of wheeled member  140  from track member  330 . That is, in order to remove wheeled member  140 , and therefore rescue chair (not shown), from track member  330 , one must lift back portion  112  upward and then return it to an angled position, such as that shown in  FIG. 4A . Doing so would be difficult or impossible once an individual is sitting within the rescue chair.  
         [0034]     The function of wheeled member  140  within track member  330  will be recognized by one skilled in the art. Due to the angle of track member  330 , such as that shown in  FIG. 3 , wheeled member  140  will turn about post  141  and the rescue chair  100  allowed to descend along track member  330  using the force of gravity alone. Accordingly, wheeled member  140  may have any number of configurations and be comprised of any number of materials to aid its turning within track member  330 . In a preferred embodiment, a surface of wheeled member  140  adapted to contact track member  330  includes a plurality of ball bearings  143 , although this is not essential.  
         [0035]     FIGS.  5 A-B show an optional safety device for use in the present invention. In  FIG. 5A , a rear view of two rescue chairs  100 ,  400  are shown in their approximate positions along a pair of track members (not shown, for purposes of clarity). As rescue chairs  100 ,  400  descend along the pair of track members, it is possible that the “uphill” rescue chair, i.e., rescue chair  400 , may descend at a rate faster than the “downhill” rescue chair, i.e., rescue chair  100 . This may be due to any number of factors, particularly the relative weights of the individuals within each rescue chair. In order to prevent a collision between the uphill rescue chair  400  and the downhill rescue chair  100 , a chock  150  or similar device may be attached to the downhill rescue chair  100  by a flexible member  152 , such as a cord, and placed within one of the pair of track members. As such, chock  150  trails behind the downhill rescue chair  100  as it descends along the pair of track members.  
         [0036]      FIG. 5B  shows a detailed view of chock  150  and its interaction with a wheeled member  444  of the uphill rescue chair  400 . Preferably, chock  150  is shaped to correspond to a surface of wheeled member  444 , although this is not essential. Chock  150  serves to impede the movement of wheeled member  444  (and therefore rescue chair  400 ,  FIG. 5A ) along the track member, thereby preventing the uphill rescue chair  400  ( FIG. 5A ) from colliding with the downhill rescue chair  100  ( FIG. 5A ).  
         [0037]     Referring now to FIGS.  6 A-B, side and top cross-sectional views of track member  330 , respectively, are shown. FIGS.  6 A-B show a friction member  334  within slot  331  of track member  330 . Friction member  334  is adapted to contact wheeled member  140  along a portion of track member  330 , thereby slowing or, optionally, stopping the descent of wheeled member  140 , and therefore rescue chair  100  ( FIG. 5A ), along track member  330 . In addition, track member  330  may, at periodic points along its length, include one or more slots  333 , through which a lock mechanism, chock, or similar device may be inserted in order to prevent movement of rescue chair  100  along track member  330 . Slot  333  may be particularly useful along horizontal portions of track member  330 , such as at a stairway landing, where users may enter and exit rescue chair  100 .  
         [0038]      FIG. 6B  shows a top cross-sectional view of  FIG. 6A . As can be seen in  FIG. 6B , friction member  334  may optionally be wedge-shaped, with a thinner portion  333  oriented in an “uphill” direction and a thicker portion  335  oriented in a “downhill” direction. As such, the friction imparted to wheeled member  140  by friction member  334  increases as wheeled member  140  descends to a downhill position  140 ′. That is, the wedge-shape of friction member  334  results in an increasing deceleration of wheeled member  140 , and therefore rescue chair  100  ( FIG. 5A ), as wheeled member  140  moves along track member  330 .  
         [0039]     Friction member  334  may be employed, for example, toward the bottom of a stairway, where it may be desirable to slow the descent of rescue chair  100  ( FIG. 5A ) before it reaches an end of track member  330 . Friction member  334  may also be employed as track member  330  approaches a stairway landing (not shown), in the case that the stairway comprises more than one flight of stairs separated by a landing, as would commonly be found in buildings having more than two stories. That is, as rescue chair  100  descended along track member  330  toward the stairway landing, friction member  334  would act to slow the descent of rescue chair  100  as track member  330  turned at the stairway landing and began another descent down the lower stairway.  
         [0040]     As noted above, in a building comprising more than two stories, a stairwell may comprise two or more stairways separated by one or more stairway landings. In such a case, the angled orientation of a pair of wheeled members (e.g.,  140 ,  142  in  FIG. 1D ) may need to be adjustable in order to avoid seat portion  114  (FIGS.  1 A-C) of rescue chair  100  (FIGS.  1 A-D) tilting from a substantially horizontal orientation as the rescue chair  100  moves to a horizontal portion (not shown) of track member  330  adjacent the stairway landing.  
         [0041]     In such a case, rescue chair  100  may include an adjustable track  160 , as shown in FIGS.  7 A-B, in which a wheeled member  140  is seated. FIGS.  7 A-B show a rear view and a side view, respectively, of adjustable track  160  and the alternative positions of wheeled member  140 . Preferably, one or both of a pair of wheeled members (e.g.,  140 ,  142  in  FIG. 1D ) are seated in such an adjustable track  160 . Adjustable track  160  includes a mechanism for moving wheeled member  140  to one or more alternative positions, i.e.,  140 ′,  140 ″. As will be recognized by one skilled in the art, any number of mechanisms may be employed to move wheeled member  140  to its alternative positions  140 ′,  144 ″, including, for example, a universal joint. In a preferred embodiment, the mechanism includes a ratcheting mechanism.  
         [0042]     Referring now to FIGS.  8 A-B, one or both pairs of wheeled members (e.g.,  140 ,  142  and  144 ,  146  in  FIG. 1D ) may be replaced with a clamp member  170  adapted to attach to and follow a cable  338  located adjacent a stairway  200  ( FIG. 3 ). As shown in  FIG. 8A , the top pair of wheeled members has been replaced with a clamp member  170  connected to rescue chair  100  by a cord  172  or similar elongate member, while the bottom pair of wheeled members (not shown) has been retained and sit within track member  332 . Clamp member  170  may comprise any number of devices known in the art, including, for example, clamp devices such as those used to secure window washing platforms. In a preferred embodiment, clamp member  170  includes a speed-regulating mechanism to control the descent of rescue chair  100 .  
         [0043]      FIG. 8B  shows a detailed view of clamp member  170  attached to cable  338 . As will be recognized by one skilled in the art, clamp member  170  may be adapted to limit the rate at which it, and therefore rescue chair  100 , descends along cable  338 . That is, clamp member  170  may incorporate a brake member or mechanism.  
         [0044]     As described above, the device and system of the present invention provide numerous advantages over known devices and systems. The simplicity and ease of storage of devices and systems of the present invention provide greater flexibility in their use. For example, a number of rescue chairs according to the invention may easily be folded and stored at a landing of a stairwell without obstructing use of the stairwell in non-emergency situations.  
         [0045]     The foregoing description of various aspects of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously, many modifications and variations are possible. Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of the invention as defined by the accompanying claims.