Patent Publication Number: US-2002011383-A1

Title: Stairlift for the disabled

Description:
BACKGROUND OF THE INVENTION  
       FIELD OF THE INVENTION  
       [0001] The invention relates to a stairlift, especially for wheelchair-bound disabled persons. The stairlift has a guide body, which is mounted such that it can be moved along a staircase. A load-receiving device is held in a vertically displaceable manner and is movable between a lowered stopping position and a raised travel position. The load-receiving device accommodates a swing-up platform, which has two swing-up hinged ramps and two separately operable, downward-swinging or upward-swinging barriers.  
       [0002] Previous stairlifts having a platform for receiving a wheelchair user have a lower and an upper guide, the upper guide simultaneously serving as a handrail. As the angle of inclination of the staircase increases, the guides have to be placed higher and higher to prevent the platform from jamming against the stairs, so that the standard measurements for a handrail were often exceeded and the interspace between the lower guide and the staircase additionally had to be covered by panels.  
       [0003] In more modern installations, in addition to the main motor there is also a spindle motor present for lowering the platform at the stopping places to allow a lower fitting of the guides. Such a system has a total of five motors (travel drive, vertical drive, floor and barrier drive).  
       [0004] German Patent No. DE 42 11 870 C2 discloses a stairlift having a load-receiving device, which is provided such that it is vertically displaceable relative to a guide bar mounted on guide rollers.  
       SUMMARY OF THE INVENTION  
       [0005] It is accordingly an object of the invention to provide a stairlift which overcomes the above-mentioned disadvantages of the heretofore-known stairlift of this general type and which requires fewer drive motors and has a simplified electrical control system.  
       [0006] With the foregoing and other objects in view there is provided, in accordance with the invention, a stairlift, including:  
       [0007] a guide body to be mounted such that the guide body is movable along a staircase;  
       [0008] a load-receiving device held in a vertically displaceable manner, the load-receiving device being movable between a lowered stopping position and a raised travel position;  
       [0009] a swing-up platform provided at the load-receiving device, the swing-up platform having two swing-up hinged ramps;  
       [0010] two barriers provided at the load-receiving device, the barriers having respective pivot axles, the barriers being separately operable and being configured as selectively downward-swinging and upward-swinging barriers;  
       [0011] two vertically movable barrier-actuating bars provided at the load-receiving device, the barrier-actuating bars having respective end sections protruding downward beyond the load-receiving device when the load-receiving device is in the raised travel position, and the barrier-actuating bars being linked to the pivot axles of the barriers;  
       [0012] one of the barrier-actuating bars being moved upward and swinging a corresponding one of the barriers up such that the corresponding one of the barriers swings out of a substantially horizontal position into a substantially vertical position when the load-receiving device is lowered into the lowered stopping position and a respective one of the end sections protrudes downward and makes contact with a floor;  
       [0013] a pretensioning device operatively connected to the swing-up platform, the pretensioning device forcing the swing-up platform upward such that, when the swing-up platform is raised out of the lowered stopping position, the pretensioning device brings the swing-up platform into an upwardly inclined, vacant position, if the swing-up platform is in an unloaded state;  
       [0014] the guide body having a tilt stop the swing-up platform having a tilt lever disposed such that, when the swing-up platform is in an unloaded state and when the load-receiving device is one of raised into the travel position and lowered, the tilt lever interacts with the tilt stop of the guide body and swings the swing-up platform selectively up and down, and the tilt lever, when the swing-up platform is loaded and in the substantially horizontal position, remains disengaged from the tilt stop;  
       [0015] rotating stops disposed at the pivot axles; and  
       [0016] two lifting bars operatively linked to the swing-up platform, the lifting bars interacting with the rotating stops at the pivot axles of the barriers such that, when the load-receiving device is in an unloaded state and is lowered, with the swing-up platform initially being in a swung-up state and with the barriers initially being in a swung-down state, the lifting bars move the barriers into the substantially horizontal position as the swing-up platform is swung down.  
       [0017] In other words, the object of the invention is achieved by a stairlift, especially for wheelchair-bound disabled persons, having a guide body, which is mounted such that it is transportable along a staircase and on which a load-receiving device is held in a vertically displaceable manner and is movable between a lowered stopping position and a raised travel position, the load-receiving device accommodating a swing-up platform, having two swing-up hinged ramps, and two separately operable, downward-swinging or upward-swinging barriers,  
       [0018] the stairlift being characterized in that the load-receiving device accommodates two vertically movable barrier-actuating bars, which, in the travel position, respectively protrude with an end section downward over the load-receiving device and are respectively linked to a pivot axle of a barrier, one barrier-actuating bar, as the load-receiving device is lowered into the stopping position and the protruding end section makes contact with the floor, being moved upward and swinging the corresponding barrier up out of a horizontal position into a vertical position,  
       [0019] a pretensioning device forces the platform upward and, as this is raised out of the stopping position, brings it in the unladen state into a slightly upwardly inclined vacant position,  
       [0020] the platform has a tilt lever, which is provided such that, when the platform is unladen and as the load-receiving device is raised into the travel position, and also as it is lowered, it interacts with a tilt stop of the guide body and swings the platform up or down, whereupon the tilt lever, when the platform is laden and in the horizontal position, remains disengaged from the tilt stop, and  
       [0021] linked to the platform, especially to the tilt lever, there are two lifting bars, which interact with a respective rotating stop on the pivot axles of the barriers and, as the unladen load-receiving device is lowered, the platform initially being swung up and the barriers swung down, move the barriers into a horizontal position as the platform is swung down, and vice versa.  
       [0022] According to another feature of the invention, the barrier-actuating bars are provided respectively on the lower end section with a roller.  
       [0023] According to yet another feature of the invention, the pretensioning device has a spring-loaded stop, which, when the platform is swung down, interacts with the load-receiving device and forces the unladen platform upward.  
       [0024] According to a further feature of the invention, the tilt stop is configured as an engagement opening for the tilt lever.  
       [0025] The rotating stops are preferably provided on the pivot axles offset by 90° relative to the barriers.  
       [0026] Expediently, the barrier-actuating bars have a locking device, which in the travel position, when the barriers are horizontal, is snapped-in and prevents the barriers from being raised.  
       [0027] Preferably, the barrier-actuating bars are connected respectively by an interposed locking bar to the pivot axles, each locking bar having a locking projection for interaction with a projection of the load-receiving device.  
       [0028] Preferably, each locking bar has a sliding slope, which, as the barriers are moved out of the swung-up position into the horizontal position, moves the locking bar past the projection.  
       [0029] According to a preferred embodiment, each locking bar, when the barrier is in the horizontal position, assumes a slightly angled-off position relative to the barrier-actuating bar, so that, as the barrier-actuating bar is actuated, a transverse force is generated which moves the locking projection out of interaction with the projection of the load-receiving device.  
       [0030] According to another feature of the invention, the hinged ramps are connected through the use of traction cables to the barriers, so that the hinged ramps are swung up approximately vertically when the barriers are swung down, are swung up by approx. 45° when the barriers are horizontal, and are angled approximately horizontally or slightly downward when the barriers are swung vertically up.  
       [0031] According to yet another feature of the invention, the load-receiving device can be moved vertically relative to the guide body through the use of a motorized spindle.  
       [0032] Alternatively it can be provided that the guide body is mounted such that it can be transported along a first (lower) and a second (upper) guide rail and has a drive mechanism interacting with a drive rail, the drive rail being formed by a perforated bar, which in the longitudinal direction has regularly spaced engagement openings and two continuous, mutually opposing running surfaces, the drive mechanism having two gearwheel-like drive wheels, which are disposed in mutually opposing configuration and receive the perforated bar between them with a radial contact force, the drive wheels having drive surfaces which are continuous in the peripheral direction and radially protruding drive projections, the drive projections interacting with the engagement openings and the drive surfaces with the running surfaces in a form-locking and force-locking drive connection, and a housing carrying the drive wheels being held pivotably on the load-receiving device so that the course of the perforated bar defines the vertical situation of the load-receiving device relative to the guide body. A form-locking connection is one which connects two elements together due to the shape of the elements themselves, as opposed to a force-locking connection, which locks the elements together by using a force.  
       [0033] In this embodiment, it can further be provided that the perforated bar, in the region of stopping places and/or end points, is guided in the direction of the first (lower) guide rail.  
       [0034] According to another feature of the invention, a drive motor is fixedly attached to the load-receiving device and has a gearbox, the housing being held pivotably about a shaft.  
       [0035] Other features which are considered as characteristic for the invention are set forth in the appended claims.  
       [0036] Although the invention is illustrated and described herein as embodied in a stairlift for the disabled, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.  
       [0037] The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0038]FIG. 1 is a diagrammatic side view of a stairlift according to the invention in a travel position, the platform, hinged ramps and barriers, as well as their actuating devices, being omitted for reasons of clarity;  
     [0039]FIG. 2 is a diagrammatic side view of a stairlift according to FIG. 1, the platform, hinged ramps and barriers, as well as the associated actuating devices, being represented and the drive being effected through the use of a perforated bar and drive wheels;  
     [0040]FIG. 3 is a view corresponding to FIG. 2, the vertical drive being effected through the use of a motorized spindle;  
     [0041]FIGS. 4, 5 and  6  are diagrammatic side views illustrating the interaction of a vertically movable barrier-actuating bar with a barrier;  
     [0042]FIG. 7 is a diagrammatic side view illustrating the interaction of a lifting bar for a barrier with a rotating stop on a pivot axle of a barrier; and  
     [0043]FIGS. 8 and 9 are diagrammatic side views illustrating the interaction of a tilt lever of the platform with a tilt stop. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0044] Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is shown a stairlift according to the invention, in which the platform and the barriers are omitted for representation reasons, at the foot of a staircase in a raised travel position, a guide body  1 , represented as substantially frame-shaped, being transportably mounted and guided with lower guide rollers  2 , provided in pairs, on a first, lower guide rail, and with upper guide rollers  4 , provided in pairs, on a second, upper guide rail  5 . In the represented embodiment, the guide rails  3  and  5  form together with vertical rods  6  a stair railing, the upper guide rail  5  serving as a handrail.  
     [0045] As can be seen from FIG. 1 and  2 , a load-receiving device  8 , which receives a load to be transported, is guided on the guide body  1  in a vertically displaceable manner, the load-receiving device  8  being provided, in the present case, with vertical guide struts  9  and cross-bars  10 , on which a drive motor  11  and further drive elements, which are described below, are held.  
     [0046] A perforated bar  13 , which is produced from a flat steel strip by punching-out of holes, is attached to the vertical rods  6  in a region between the guide rails  3  and  5  and runs essentially at a constant distance from or parallel to the guide rails, whereas, in the starting region of the lift in front of the lowermost stair  15  of the staircase, it is guided downward in the direction of the first guide rail  3  and, in its lower end region, runs approximately or completely vertically.  
     [0047] Flange-mounted on the drive motor  11  is a gearbox  40 , on which a pair of gearwheel-like drive wheels  17 ,  18  are pivotably held, which receive the perforated bar  13  in form-locking and force-locking (positive and non-positive locking) connection between them.  
     [0048] The perforated bar  13  has on its top and bottom side, in each case adjacent on both sides to the holes or engagement openings  20 , mutually opposing running surfaces  23 ,  24 , with which the drive wheels interact.  
     [0049] The cylindrical drive wheels have inserted bolts  25 , whose end sections protruding from the drive wheels are frustoconically tapered, the engagement openings of the perforated bar being correspondingly formed in double frustoconical configuration.  
     [0050] The drive wheels further have on their outer peripheral faces annular or cylindrical drive surfaces, which are respectively continuous laterally adjacent to the bolts in the peripheral direction and with which the drive wheels interact with the running surfaces.  
     [0051] The drive wheels  17 ,  18  are wedged in rotationally fixed configuration on shafts  30 ,  31 , on which coupling gearwheels are likewise wedged in rotationally fixed configuration, so that the drive wheels are coupled together in terms of their drive, having the same rotation speed in opposite rotational directions. The shafts  30 ,  31  are mounted in a housing  35 , one shaft being spring-loaded against the other and the contact force being able to be set such that, for example, 30% or even 50% of the drive force is transmitted by frictional engagement.  
     [0052] The housing  35  is held pivotably on a gearbox  40 , so that the housing can perform a pivotal motion about the longitudinal axis of the shaft  30  and can hence follow a predefined course of the perforated bar  30 .  
     [0053]FIG. 2 shows the load-receiving device  8  at the lower end point of its motion or in a lower end position, the drive mechanism including drive motor  11 , gearbox  40  and drive wheels  17 ,  18 , having been transported downward along the perforated bar  13 . In a region in front of the lowermost stair  15  of a staircase, the load-receiving device  8  is thus in a position which enables a wheelchair or similar to be loaded or driven up onto a horizontal platform  50  of the load-receiving device.  
     [0054] In order to move the stairlift along the staircase, the load-receiving device  8  must initially be raised by a vertical height difference corresponding to the height of a or the lowermost stair  15  of the staircase, since the load-receiving device would otherwise butt against the stairs.  
     [0055] To this end, in a first motional section, the load-receiving device  8  is moved vertically upward, for which merely the drive motor  11  has to be activated, since the perforated bar  13  guiding the load-receiving device is correspondingly vertically guided. As soon as the drive wheels  17 ,  18  reach the curved transitional section of the perforated bar, the load-receiving device has also reached a sufficient height, so that the lift acquires a travel motion directed obliquely upward in accordance with the course of the perforated bar. The housing  35 , holding the drive wheels  17  and  18 , hereupon automatically pivots in accordance with the local inclination or curvature of the perforated bar.  
     [0056] Since the load-receiving device automatically and forcibly follows the course of the perforated bar, the guide rails  3 ,  5  can have a course which is practicable as a stair railing without having to pay regard to the motional course (lead) of the load-receiving device. In this case, the bearing frame in front of the first stair can be raised, for example, by 250 or even more, for example, 400 mm, which corresponds to a lowering of the guide rails relative to the load-receiving device by a corresponding measurement.  
     [0057]FIG. 3 shows an alternative embodiment of a stairlift, in which the vertical transport motion of the load-receiving device relative to the guide body is effected through the use of a threaded spindle  37  driven by a drive motor  36 . The drive of the guide body can be effected, for example, directly by driving of the guide rollers  2  and/or  4 .  
     [0058] For illustration of the further components necessary for the transport of a wheelchair-bound disabled person, such as platform, hinged ramps and barriers, reference should be made below to FIG. 2 and FIGS.  4  to  9 .  
     [0059] A platform  50  is pivotably fitted to the load-receiving device  8  and can be swung up between a substantially horizontal, laden (loaded) position and a space-saving vertical position. FIG. 7 shows the mounting of the platform  50  on the load-receiving device  8  in a diagrammatic side view, the pivotal motion being effected about a pivot axle  51 . As further shown by FIG. 7, in the platform  50  there is disposed a stop bolt  53 , which is pretensioned through the use of a spring (assembly of cup springs)  52  and which presses with a pretensioning force against the lower end section of the load-receiving device. This pretensioning device has the effect that, as the platform or load-receiving device  8  is elevated in the empty (unladen) state, the platform  50  is pivoted slightly upward as soon as a tilt lever  55  enters with its free end section or its tip into the region of an engagement opening  56  of a tilt stop  58  fixedly connected to the guide body  1 , the effect being that, as the unladen (unloaded) load-receiving device  8  is further elevated relative to the guide body  1  and the tilt stop  58  fixedly connected thereto, the empty platform is pivoted up (intermediate position FIG. 9, end position FIG. 8). As shown by FIGS. 8 and 9, the then load-free stop bolt  53  has partially departed there from its guide in the platform  50 .  
     [0060] For illustration of the actuation of the barriers, reference should be made, in particular, to FIGS.  4  to  6 . Two mutually independently movable barriers  61 ,  62  (FIG. 2) are present, in which the barrier disposed toward the ascending side on a staircase is referred to as the uphill barrier and the barrier disposed toward the descending side is referred to as the downhill barrier. At a stopping point of a stairlift at the lower end of a staircase, both barriers are expediently opened by being swung vertically upward, whereas at a stopping point at an upper end of a staircase only the uphill barrier, for safety reasons, can be opened, whilst the downhill barrier must remain closed. According to the invention, this is realized automatically as follows.  
     [0061] The load-receiving device accommodates two vertically movable barrier actuating bars  63 , which in the travel position (FIG.  4 : laden, FIG. 6: unladen) respectively protrude with an end section downward out of the load-receiving device and beyond, the lower end section of the barrier-actuating bars  63  expediently being provided respectively with a roller  64 . As shown by FIG. 5, as the load-receiving device is lowered at a stopping point of the stairlift into the stopping position, through contact of the protruding end section or roller  64  with the floor, a barrier-actuating lever  63  is moved upward, so that the associated barrier  61  or  62  (or both) is swung up out of a horizontal position (FIG. 4) into a vertical position (FIG. 5). Since the end section of the barrier-actuating bar  63  assigned to the downhill barrier, when a stop is made in front of the upper end of a staircase, does not come into contact with the floor, the downhill barrier remains automatically closed.  
     [0062] The barrier-actuating bar  63  is connected at its upper end by an interposed locking bar  66  to a link lever  67 , which, for its part, is fastened on a pivot axle  68  of the barrier. As further shown by FIG. 4 and  5 , the locking bar  66  has a locking projection  70  for interaction with a corresponding projection  71  of the guide body  1 , which, on its bottom side, is provided with a sliding slope  72 , which, upon a downward-directed motion of the barrier-actuating bar  63 , moves the locking bar past the locking projection  71 .  
     [0063] As can be seen from FIGS.  7  to  9 , linked to the tilt lever  55  of the platform  50  are two lifting bars  75 , which interact with a respective rotating stop  76  on the pivot axles  68  of the barriers and a stop  78  fixedly fitted to the guide body  1  and serve to raise the barriers, as the unladen load-receiving device is lowered, out of the fully swung-down position of the barriers (FIG. 6) into the horizontal position (FIG. 7). As is further illustrated in detail, as the unladen load-receiving device is lowered the platform is swung up and the barriers swung down, as shown by FIG. 6, whereupon initially, prior to the barrier-actuating bars  63  making contact with the floor, the platform  50 , through interaction of the tilt lever  55  with the engagement opening  56  of the tilt stop  58 , is swung horizontally downward out of its vertical, space-saving position and, at the same time, both barriers are jointly raised by the lifting bars  75 , in interaction with the rotating stop  76 , out of their swung-down position into the horizontal position, an intermediate position within this process being shown in FIG. 9.  
     [0064] As further shown by FIG. 7, the lifting bars  75  are not fixedly connected to the rotating stops  76 , but interact with these via the fixed stops  78 , which are fitted to the guide body  1 . This produces a clamping effect for the barriers in the horizontal position (FIG. 7), so that the barriers in this position are prevented both from being raised (as a result of the locking device formed from locking projection  70  and projection  71 ) and from being pressed down (due to interaction of rotating stop  76 , lifting bar  75  and stop  78 ).  
     [0065] The sequence of functions (upward and downward, laden and unladen) is as follows:  
     [0066] 1) Laden downward: the load-receiving device and hence the platform is lowered, in accordance with the course of the perforated bar  13  (or alternatively with the routing of the spindle  37 ), at stopping points or end points of the stairlift. The platform is initially horizontal, the barriers lie horizontally. After the roller  64  of one or both barrier-actuating bars  63  makes contact with the floor, one or both barriers  61  and/or  62  is/are swung upward. The locking action of the locking projection  70  is surmounted by virtue of the fact that, due to the angled-off configuration of barrier-actuating bar  63  and locking bar  66 , a transverse force is generated at the connection point between the two bars, which transverse force moves the locking projection  70  away from the corresponding projection  71  (to the left in FIG. 4).  
     [0067] 2) Laden upward: here the platform is initially horizontal, the barriers are swung vertically upward. The barriers move out of the position represented in FIG. 5, under their own weight, into the horizontal position, whereupon the locking projection  72  snaps in beneath the projection  71 . Due to the interaction of the rotating stops  76  with the lifting bars  75  and the stops  78 , the barriers are also prevented from being further swung down or pressed down (FIG. 7).  
     [0068] 3) Empty upward: here the platform is initially horizontal, the barriers are swung vertically upward. When the platform is driven upward, the barriers move downward under their own weight (starting from the position according to FIG. 5) and snap in (FIG. 4). The spring  52  slightly raises the platform, through the use of the stop bolt  53 , as soon as the tilt lever  55  enters with its tip into the engagement opening  56 . Upon further raising, the tilt lever  55 , through interaction with the engagement opening  56 , is pivoted and moves the platform upward (FIG. 9). The lifting bars  75  are moved downward, so that a delayed release of the barriers comes about through the interaction of lifting bars  75  and rotating stops  76 , and stops  78 , and the barriers are swung downward over the platform (FIG. 8 and  6 ).  
     [0069] 4) Empty downward: Here the platform is initially swung up, the barriers are swung down (FIGS. 8 and 6). The platform is moved downward, together with the load-receiving device  8 , relative to the guide body  1 . The tilt lever  55  makes its way into the engagement opening  56  (FIG. 9) and brings about a pivotal motion of the platform in the horizontal direction. At the same time, the barriers are moved out of the swung-down position by the lifting bars  75  and the rotating stop  76  into the horizontal position (FIG. 9). Following contact with the floor by one or both rollers  64 , one barrier-actuating bar or both is/are moved upward, so that the respective barrier(s) is/are likewise swung vertically upward (FIG. 5).  
     [0070] The hinged ramps  54  (FIG. 2) are coupled by a suitable traction device, for example a traction cable  57  or a chain, and a corresponding reeling device  59  on the pivot axles  68  of the barriers fixedly with the swing motion of an associated barrier  61  or  62 , so that a hinged ramp is in the horizontal or slightly downward angled position represented in FIG. 2 or  3  whenever the associated barrier  61  or  62  is in the vertically upward swung position, whereas the hinged ramp is in a position swung by about 45° upward when the corresponding barrier is lying horizontally, and is swung vertically upward when the barrier is swung completely downward.  
     [0071] A security device, which is not shown in the drawings, is provided against “unauthorized” raising of the barrier-actuating bar(s)  63  during travel so that, if this should happen, the lift immediately comes to a halt.  
     [0072] Furthermore, in a manner which is known per se, a trapping or catching mechanism is present, which, when a perforated bar  13  is used, can advantageously interact therewith.  
     [0073] In addition to the complexity (five drive motors) described in the introduction, according to the invention an additionally necessary locking of the barriers, all barrier and floor switches and all safety protections for the motors are also eliminated.  
     [0074] All that remains are one switch each and the by-pass circuit for monitoring the locks in the region of the stopping places in connection with early-opening barriers, similar to the case of early-opening doors of passenger elevators.