Patent Publication Number: US-10787342-B2

Title: Wheelchair lift apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to a wheelchair lift apparatus. 
     BACKGROUND 
     Typically, when a wheelchair user encounters stairs or other obstacles which the wheelchair is incapable of safely traversing along the user&#39;s designated path or route, the user must either have manual assistance or elect another route. For example, two or more individuals manually may lift the user in the wheelchair up or down a flight of stairs. Or the user may in some instances seek and find special accommodations for those with disabilities e.g., a wheelchair ramp or the like. However, some public buildings and many private residences, among other things, do not have such accommodations. Further, by standing individuals may not be present or able to assist the wheelchair user in these circumstances. Thus, there is a need to provide a means for the wheelchair user to move in the wheelchair between platforms or paths having different heights or elevations (e.g., to negotiate stairs and the like). 
     SUMMARY 
     According to an embodiment of the invention, there is provided a wheelchair lift apparatus that includes a stand that includes a pair of inclined rails; and a platform adapted to carry a wheelchair, wherein the platform includes a driving portion and a driven portion for moving the platform along the rails, wherein, when the driving portion actuates the driven portion in a first direction, the platform ascends along the rails, wherein, when the driving portion actuates the driven portion in a second and opposite direction, the platform descends along the rails. 
     According to another embodiment of the invention, there is provided a wheelchair lift apparatus for a stairway that includes a stand that includes an upper support, a lower support, and a pair of rails coupling the upper and lower supports to one another; and a platform adapted to carry a wheelchair-bound individual, wherein the platform includes a driving portion and a driven portion for moving the platform along the rails, wherein, when the driving portion actuates the driven portion in a first direction, the platform ascends along the rails, wherein, when the driving portion actuates the driven portion in a second and opposite direction, the platform descends along the rails. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       One or more embodiments of the invention will hereinafter be described in conjunction with the appended drawings, wherein like designations denote like elements, and wherein: 
         FIG. 1  illustrates a perspective view of a wheelchair lift apparatus in an exemplary environment; 
         FIG. 2  illustrates a perspective view of a stand of the lift apparatus located on a stairway; 
         FIG. 3  illustrates a perspective view of a platform assembly of the lift apparatus; 
         FIG. 4  is an enlarged perspective view of a portion of the platform assembly shown in  FIG. 3 , wherein a portion of a trolley housing is removed to expose the component therein; 
         FIG. 5  illustrates an enlarged perspective view of a portion of the wheelchair lift apparatus on the stairway; 
         FIG. 6  illustrates a top view of the wheelchair lift apparatus; 
         FIGS. 7-8  illustrate side views of the wheelchair lift apparatus, wherein the platform assembly is respectively in a lower position and in an upper position; 
         FIG. 9  is a schematic diagram of a circuit card assembly; 
         FIG. 10  is a top view of embodiment of a stand having telescopic guide rails; and 
         FIG. 11  is a cross-sectional view of another embodiment of a base member of a support. 
     
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT(S) 
     A wheelchair lift apparatus or assembly  10  is described herein that transports a wheelchair (or wheelchair-bound individual)  12  between a bottom or lower position  14  and to a top or upper position  16  of an obstacle  18  (or vice-versa), as shown in  FIGS. 1, 7-8 . More particularly, the apparatus  10  of  FIG. 1  includes a stand  20  and a mobilized platform assembly or platform  22  carried by the stand  20  that enables a wheelchair-bound person  12  to ascend or descend over the stairs  18 . Further, when the apparatus  10  is not in use, it does not inhibit foot-traffic use of the stairs  18  (e.g., by those not in wheelchairs). For example, as will be explained in greater detail below, when the apparatus  10  is not in use, non-wheelchair-bound individuals may step onto the platform  22 , walk through the platform  22 , and traverse the stairs  18 . Furthermore, as will become apparent from the description below, the apparatus  10  is generally modular, does not require time-intensive installation, nor does it need to be fixed to or coupled to existing structure (e.g., to the stairway, to an adjacent interior or exterior wall, to a stairway handrail, etc.). For example, it can be a stable, freestanding solution for wheelchair-bound individuals desiring to traverse stairs. As used herein, the term lift apparatus (or lift assembly) includes an apparatus that lifts or raises an object and/or individual, an apparatus that lowers an object and/or individual, or a combination thereof. 
     As shown in  FIG. 2 , the stand  20  of the apparatus  10  may include two or more supports  28 ,  30  and two guide rails  32 ,  34  which couple the supports  28 ,  30  to one another. The upper and lower supports  28 ,  30  may be identical; therefore, only one will be described. 
     The illustrated support  30  includes a U-shaped body  36  having an axially extending base member  38  and two upright members  40 ,  42  extending radially outwardly therefrom. More particularly, the upright members  40 ,  42  may be identical to one another and may extend in parallel; however, this is not required. For example, each upright member  40 ,  42  may extend at a right angle with respect to the base member  38 ; however, this is not required. Further, in at least one embodiment, the upright members  40 ,  42  may have features enabling adjustment in length (e.g., they may be telescopic or otherwise extendable). While a U-shaped body  36  is shown, other shapes are also contemplated. 
     According to one embodiment, the support  30  may be formed in a single, unitary piece—e.g., using extrusion, bending, welding, and/or other suitable manufacturing techniques; however this is not required. For example, in one non-limiting example, the support  30  may be comprised of three extruded aluminum pieces which each have a rectangular cross-section and are adjoined by welding. Of course, this is merely one non-limiting example; further, the support  30  may be comprised of any suitable metal, plastic, or other material. 
     Thus, in one embodiment, a diameter of the upright members  40 ,  42  and the base  38  member may be generally uniform. Further, the diameter of the base member  38 —adapted for foot traffic to pass thereover—may have a generally low profile. And in at least one other embodiment (as shown in  FIG. 11 ), a base member  38 ′ may be shaped as a generally flat bar which has at least one axially extending edge that tapers  44  radially outwardly from a longitudinal axis B (of the base member  38 ′). The tapered edge  44  may promote safety by inhibiting non-wheelchair-bound individuals from tripping on the base member  38 ′ as they traverse the stairway  18  on foot, as will be explained more below. 
     Returning to  FIG. 2 , in at least one implementation, a user interface device ( 50 ,  52 ) is located at or on each of the upper and lower supports  28 ,  30  (or even on rail). For example, the user interface devices  50 ,  52  may be integral to one of the upright members  40 ,  42 , or the devices  50 ,  52  may be detachable therefrom. The user interface devices  50 ,  52  may include a transceiver (not shown) and may be adapted to communicate by wire or wirelessly with platform electronics  54  (shown in  FIGS. 1 and 6 ) as will be explained in greater detail below. In at least one embodiment, the devices  50 ,  52  include wireless transceivers and communicate according to any suitable short range wireless communication (SRWC) protocol (e.g., such as Wi-Fi, Bluetooth, BLE, and the like). 
     More particularly, the upper user interface device  52  may include a call switch  56  that enables a wheelchair-bound individual at an upper level or landing  58  of the stairway to retrieve or call the platform when it is located at a lower level  60  (e.g., a lower floor or ground); see  FIGS. 1-2 . Similarly, the lower user interface device  50  may include a call switch  62  that enables a wheelchair-bound individual  12  at the floor  60  to retrieve or call the platform  22  which may be located at the landing  58 . 
     As shown in  FIG. 2 , the guide rails  32 ,  34  of the stand  20  also may be identical; therefore, only one will be described. According to one embodiment, the rail  34  may include an axially extending body  64  adapted to support the platform  22  weight. According to one embodiment, each rail  32 ,  34  may be formed in a single, unitary piece—e.g., using extrusion and/or other suitable manufacturing techniques; however this is not required. For example, in one non-limiting example, the rail  34  may be comprised of a single extruded aluminum piece which has a rectangular cross-section. Of course, the rail  34  may be comprised of any suitable metal, plastic, or other material. Other rail implementations include multi-piece, telescopic rails  32 ′,  34 ′ such as those shown in  FIG. 10 . 
     As will be explained in greater detail below, the body  64  of the rail  34  may have a first or upper axially extending track region  66 , a second or bottom axially extending track region  68 , and a third or lateral axially extending track region  70 . The rail  34  may be arranged so that the lateral track region  70  faces inboard—e.g., so that it faces a corresponding lateral track region  70  (of the other rail  32  which also faces inboard). The rail  34  may extend between the upper and lower supports  28 ,  30  and at least an additional or extending portion of the rail  72  may extend between the lower support  28  and the floor  60 , as shown in  FIG. 2 . As shown in the accompanying figures (see  FIGS. 1 and 7 ), this extending portion  72  enables the platform  22  to traverse along the rails  32 ,  34  so that the platform  22  may be nearer to the floor  60 . 
     For example, the extending portion  72  of the rail  32  (as well as rail  34 ) may contact or nearly contact the floor  60 . In instances where the portions  72  touch the floor  60 , these extending portions  72  may provide additional stability to the stand  20 . As will be explained below, the length of the extending portions  72  may correspond to one or more dimensions of the platform  22 . 
     In one implementation, at least one guide rail  34  includes a stop or abutment  76  extending radially outwardly of the rail  34 . For example, in  FIG. 2 , two are shown; and in this illustrative example, the stops are nearer the respective upper ends  78 ,  80  of the guide rails  32 ,  34  on the upper track regions  66 . In other embodiments, the stops  76  could protrude from the lower region(s)  68 , the lateral track region(s)  70 , or any other suitable part of the guide rails  32 ,  34 . As will be explained more below, this stop  76  may be used to limit travel of platform  22  along the rail  34 . 
     The illustrated rails  32 ,  34  are shown coupled to the supports  28 ,  30  on inboard sides  82 ,  84  of the upright members  40 ,  42 ; however, this is not required. For example, the rails  32 ,  34  could be coupled to the respective ends (or tops) of the upright members  40 ,  42  or in any other suitable fashion that permits the platform  22  to traverse therebetween. The coupling of the rails  32 ,  34  to the supports  40 ,  42  should be construed broadly to include using any suitable fasteners (e.g., clips, bolts, screws, pins, etc.), weldments, keying features, and the like. In at least one embodiment, fasteners are used to assemble the rails  32 ,  34  to the supports  40 ,  42  enabling the easier transport, assembly, and disassembly of the lift apparatus  10 . 
     When the stand  20  is assembled, the lower support  28  may be located on the floor  60  and the upper support  30  may be located near the landing  58 . More particularly, in implementations where the wheelchair lift apparatus  10  is used on stairs  18 , the upper support  30  may be located on a first step  90  just below the landing  58 . While this is not required, this more generally may align the platform  22  with a surface  92  of the landing  58 , as described more below. For example, other arrangements are possible wherein both supports  28 ,  30  are located on steps, the upper support  30  is instead located on the landing  58 , etc. In addition, a slope or inclination angle of the rails  32 ,  34  may be generally parallel to a slope or inclination (e.g., a rise/run) of the stairs  18 ; however, this is not required either. The slope of many conventional stairways is in accordance with the so-called “ 7/11 rule”—i.e., seven units of rise for each eleven units of run. Thus, in at least one embodiment, the slope of the assembled rails  32 ,  34  is approximately 0.64 (or 7/11). 
     It should be appreciated that the assembled stand  20  may be freestanding—e.g., while the rails  32 ,  34  may be coupled to the supports  28 ,  30 , the supports  28 ,  30  and/or rails  32 ,  34  need not be fixed to anything else. That is, the structure&#39;s configuration—coupled with the weight and design of the platform  22  (discussed below) may not require any anchoring of the supports  28 ,  30  and/or rails  32 ,  34  to existing structure (e.g., such as a wall, the staircase, etc.). As used herein, the term freestanding means not fixed, not attached, not connected, not coupled, and not adhered to walls, stair steps, banisters, or the like. 
     Turning now to the platform  22  shown in  FIGS. 3-5 , the platform may include a base  100  sized to support an individual in a wheelchair, two carriers or carrier portions  102 ,  104  which couple the base to the rails  32 ,  34 , and a mobility or powertrain system  106  integrated with the stand  20  that facilitates hands-free transport between the landing  58  and the floor  60 . In at least one implementation, the base  100  may include a first or upper frame (or shelf)  108  coupled to a second or lower frame (or shelf)  110 . The upper frame  108  may include any suitable structural body to support a wheelchair-bound individual  12  (e.g., it may be adapted to carry as much as 600-800 pounds (lbs)). As shown in  FIG. 3 , the body includes a peripheral member  112  and a number of cross-members  114  coupled to the peripheral member  112  to provide rigidity and strength; of course, this is merely exemplary. The upper frame  108  also may include a plate  116  coupled to a top side  118  of the body (or the plate may be integral thereto). A surface  120  of the plate  116  is preferably adapted to facilitate ease-of-rolling of the wheels of user&#39;s wheelchair  12 . For example, the surface  120  may be smooth, or may be generally flat but have slip-resistant features (e.g., relatively small protrusions, ridges, depressions, channels, holes or grating, etc.). According to one embodiment, the surface  120  may be at least 36 inches wide (e.g., laterally) and 36 inches deep (e.g., between a leading edge  122  of the platform  22  and a trailing edge  124  thereof). 
     According to one embodiment, the upper frame  108  also includes one or more hinged ramps or chocks  126 ,  128  which may promote safety during use of the platform  22  (see  FIG. 5 ). For example, a first hinged ramp  126  may be located at the leading edge  122  and may facilitate access to and from the landing  58 . And for example, a second hinged ramp  128  may be located at the trailing edge  124  and may facilitate access to and from the lower floor  60 . A preferred embodiment includes both ramps  126 ,  128 . The length of the first and second hinged ramps  126 ,  128  may vary; however, in at least one embodiment, the ramps  126 ,  128  extend radially outwardly from at least one hinge element on the platform  22  and may be about 4 to 6 inches long. 
     In at least one embodiment, the first and second hinged ramps  126 ,  128  each include a safety sensor  130 ,  132  indicating whether the respective ramp  126 ,  128  is in a first or upward-facing position or in a lowered or down position (e.g., with respect to the base). The safety sensors  130 ,  132  may be in wired or wireless communication with platform electronics  54 . And as will be explained more below, during operation, the ramps  126 ,  128  may be required to be in the upward-facing position in order for the mobility system to mobilize the platform  22 . For example, in the upward-facing position the ramps  126 ,  128  may enclose or trap the wheels of the wheelchair  12  and provide a barrier or interference that inhibits the wheelchair-bound individual  12  and his/her chair from rolling off the platform  22  during transport. In addition, when the one or more hinged ramps  126 ,  128  are in the down position, the ramps  126 ,  128  may facilitate easier access onto and off of the platform  22  by wheelchair-bound individuals  12 . 
     The lower frame  110  may be constructed similarly to the upper frame  108 ; therefore, it will not be re-described here. When assembled, the lower frame  110  may be spaced from the upper frame defining a cavity  140  therebetween ( FIG. 3 )—and the cavity  140  may be suitably sized to accommodate components of the mobility system, as will be described more below. According to one implementation, a height of the cavity  140  (or a spacing between the upper and lower frames  108 ,  110 ) is approximately 3-6 inches; however, this is merely an example and other spacing embodiments are possible. In at least one embodiment, the cavity  140  may be enclosed using walls around the cavity  140  (coupled to the upper and lower frames  108 ,  110 ), etc. to minimize or inhibit contact between the mobility system components and the apparatus&#39;  10  environment (e.g., rain, snow, etc.). 
     In one embodiment, the lower frame  110  includes a contact or proximity sensor  142  mounted on a bottom side  144  thereof for detecting when the platform  22  is close to or in contact with the floor  60 . For example, one non-limiting implementation of this sensor  142  is a pressure sensor having a plunger which is actuated as the bottom side of the platform  22  touches the floor; e.g., when actuated, the sensor  142  may communicate with platform electronics  54  which in turn may cease driving or moving the platform  22 , as will be explained more below. 
     Other embodiments of the base  100  include implementations without the lower frame  110 . For example, the mobility system components may be mounted in other locations on the platform  22  (e.g., such as on an underside of the upper frame  108 ). Further, a cover or hood (not shown) could be located thereover to protect components from weather elements and the like. 
     Turning now to the carriers  102 ,  104  best shown in  FIGS. 3 and 5 , each of the carriers  102 ,  104  may be identical; therefore, only one will be described below. According to one embodiment (see  FIG. 5 ), carrier  102  may include a bracket  148  adapted to carry at least one wheel assembly or trolley  150  which is/are adapted to enable the platform  22  to traverse upwardly and downwardly along a respective rail (e.g.,  32 ). The illustrated bracket  148  is embodied as a post  152  that extends outwardly of the upper frame  108  and a connecting segment  154  that extends from an upper end  156  of the post  152  to the upper frame  108  having a slope or inclination angle that may be similar to the slope of the rail  34 ; of course, this is merely an example. In at least the illustrated implementation, the post  152  is located proximate to the leading edge  122  of the base  100 , while the connecting segment  154  adjoins the upper frame  108  in a location that is proximate to the trailing edge  124  of the base. In at least one embodiment, the length of the extending portion  72  of the guide rail  34  (discussed above) may be at least as long as the length of the connecting segment  154 , so that the platform  22  does not fall off of or derail from the lower ends of the guide rails  34 . 
     Other carrier embodiments are contemplated as well. For example, each carrier  102 ,  104  could comprise two posts  152  extending outwardly from the base (e.g., a longer post and a shorter post); or each carrier  102 ,  104  could comprise a triangularly-shaped wall that extends outwardly from the base, etc. In at least one embodiment, the carriers are located at lateral or outboard regions  158 ,  160  of the platform—e.g., to provide adequate space for the user&#39;s wheelchair  12  on the surface of the base  100 , and to provide additional space for foot traffic. 
     In at least one embodiment, the bracket  154  (e.g., the connecting segment) carries two trolleys  150 —e.g., wherein one trolley is spaced farther from the base than the other trolley; however, two trolleys are not required, nor is this particular arrangement required. Each trolley  150  may be identical; therefore, only one will be described below. The trolley  150  may comprise any device which both secures the platform  22  to the rail  34  and promotes travel therealong. For example, the trolley  150  may include a housing having wheels, bearings, lubricants, etc. to traverse smoothly along the guide rails  32 ,  34  with minimized resistance while also positively inhibiting a derailing event (e.g., where the platform  22  slips off the guide rails  32 ,  34  or the like). For example, the illustrated embodiments include a housing  162  and a three wheel set  164 , wherein the wheels??? are adapted to contact and roll along different axial sides of the guide rail  34  (see also  FIG. 4 ). For example, one wheel may ride along the upper track region  66 , another wheel along the lower track region  68 , and a third wheel along the lateral track region  70  in the manner shown and described in U.S. Pat. No. 5,272,984, the entirety of which is incorporated by reference. This is merely an example; other implementations are possible. 
     One of the trolleys on each carrier  102 ,  104  (e.g., the uppermost trolley) may include a contact or proximity sensor  166  mounted on a side  168  of the housing that faces the upper support  30 ; this sensor  166  may be used to detect instances when the platform  22  is close to the landing  58 . For example, one non-limiting implementation of this sensor  166  is a sensor having a plunger which is actuated when the sensor  166  on the trolley  150  engages the stop  76  on rail  34  (e.g., or rail  32 ), which is adapted to stop movement of the platform  22 , as described below. This is merely one example; other embodiments are also possible. 
     In at least one embodiment, one or more handrails may be provided on the platform as well. For example,  FIGS. 3 and 5  illustrates a pair of U-shaped handrails  170  extending from the upper frame  108  (and surface  120 ) spaced slightly inboard of the carriers  102 ,  104 . These may be provided to assist the wheelchair-bound individual  12  when ingressing or egressing from the platform  22 . In at least one embodiment, one of the handrails  170  may carry a second user interface device  172 . The second user interface device  172  may include at least one operational switch  174  that, when actuated, sends a wired or wireless signal to the platform electronics  54  (discussed below) indicating that the user  12  wishes to ascend (or descend) the stairway  18 . One non-limiting example includes the operational switch  174  being a three-position rocker switch—(positions of the switch corresponding to platform commands of ‘up,’ ‘down,’ or ‘neutral’). 
     Now turning to the mobility system  106  (see  FIG. 6 ), the system may include a number of components such as a driving portion or motor  180 , an onboard power source  182  to provide power to the motor, a driven portion or winch  184  which may be driven by the motor, a pair of cables  186 ,  188  coupled between the stand  20  and the winch  184 , a circuit card assembly (CCA)  190 , and one or more sensors (e.g., such as  130 ,  132 ,  142 ,  166 , etc.). According to one embodiment, the driving portion  180  is an electric motor and the power source  182  is an onboard battery; however, this is not required (e.g., other implementations are possible). A shaft (not shown) of the motor  180  may drive the winch  184  to wind and unwind the cable(s)  186 ,  188 , as will be appreciated by those skilled in the art. As will be appreciated from the description below, the motor  180  may have adequate power and torque to overcome the weight of the platform  22 , its cargo (e.g., a wheelchair-bound individual  12 ), and any other opposing forces (e.g., friction between the trolleys and the rails, etc.). 
     As shown in  FIG. 6 , in at least one embodiment, the pair of cables  186 ,  188  may be used to lift and lower the platform  22 . More particularly, one end  192  of the first cable  186  may be coupled to the winch  184 , and an opposite end  194  may be coupled or anchored to the upper support  30  (e.g., to one of the upright members  40 —see also  FIG. 5 ). Similarly, one end  196  of the second cable  188  may be coupled to the winch  184 , and an opposite end  198  may be coupled or anchored to the other upright member  42  of the upper support  30 . In addition, one or more cable routing elements  200 ,  202  may be used to locate the cables  186 ,  188  around features of the stand  20  and platform  22 —and may be arranged so not to be trip hazards to foot traffic that traverses the platform  22 . For example, the first and second cables  186 ,  188  each could be routed from the winch  184  outwardly from the platform&#39;s base  100  to respectively located outboard pulleys, and from the respective pulleys, to the upright members  40 ,  42  of the upper support  30  (e.g., under or below the rails)—e.g., so that the first and second cables  186 ,  188  do not interfere with a foot path along the stairway  18 . The illustrated cable routing elements  200 ,  202  are embodied as pulleys or sheaves; however, this is merely one example and others are possible (e.g., eyelets, grommets, etc.). Thus, it should be appreciated that when the motor  180  drives the winch in a first direction (e.g., winding clockwise), tension is placed on the cables  186 ,  188 , and the platform  22  may be drawn toward the landing  58 . Similarly, when the motor  180  drives the winch  184  in a second, opposite direction (e.g., unwinding or counter-clockwise), the platform  22  may be lowered toward the floor  60 . 
     In the illustrated embodiment, a pair of cables are used; however, this is not required. For example, a single cable could be used in some embodiments. However, using two cables provides redundancy—e.g., in the event the first cable  186  fails, the second cable  188  may inhibit a wheelchair-bound individual  12  and his/her wheelchair from sliding rapidly down the guide rails  32 ,  34  and becoming injured. 
     The circuit card assembly  190  (CCA, shown in  FIG. 9 ) may include a control circuit  206  adapted to regulate the speed of the motor  180  and control the lift or elevating operations of the platform  22  based on sensor and switching input. For example, the circuit  206  may include any suitable hardware components, software components, or a combination thereof—including, but not necessarily requiring, a processor  208  and memory  210  storing instructions executable by the processor  208 . It should be appreciated that a processor and memory are described below; however, the control circuit  206  could be arranged using discrete electronic components instead. 
     For example, instructions stored in memory  210  may include receiving an indication (a wired or wireless electrical signal) from the call switch  56  and retrieving the platform thereby. To illustrate, a signal may be received by a transceiver  212  on the control circuit  206  from the lower call switch  62 , the processor  208  may determine that the platform  22  is at the landing  58 , and the processor  208  may control the motor  180  to lower the platform  22  to the lower position  14 . Of course, a similar operation may be performed when the platform  22  is at the floor  60  and a signal is received from the upper call switch  56 . To accomplish this, additional sensors may be used; for example, the motor  180  may include a position sensor  214  (see  FIG. 6 ) that indicates how much of the cable(s) are unwound—and the processor  208  may determine the platform&#39;s  22  location based on an electrical value received from the position sensor  214 ; other position sensors are also possible. 
     Other instructions may include receiving an indication (from the operational switch  174  on the handrail) that a wheelchair-bound user  12  is on the platform  22  and wishes to ascend to the landing  58 . Before actuating the motor  180 , the processor  208  may determine whether the hinged portions  126 ,  128  are in the upwardly-facing positions using input from the safety sensors  130 ,  132 , and if it is determined that both hinged portions  126 ,  128  are in the upwardly-facing positions, then the processor  208  may control the motor  180  to turn the winch  184  in the first direction so that the platform  22  ascends the guide rails  32 ,  34 . Alternatively, upon receiving an indication from switch  174 , the hinged portions  126 ,  128  could raise automatically in response a trigger by the processor  208 ; then actuate the winch  184  so that the platform ascends the rails. Regardless, during the ascension, when the processor  208  receives an electrical signal from the trolley sensor  166  (e.g., when the sensor contacts the stop  166  on the rail  32  and/or  34 ), the processor  208  may cease actuating the motor  180  in this first direction. Thus, the sensor  166  may inhibit the platform  22  from progressing upwardly to the point that the platform  22  falls off the guide rails  32 ,  34 . Additionally, input from the sensor  166  may inhibit the winch  184  from over-winding the cable(s)  186 ,  188  in the first direction—e.g., thereby preventing the cable(s)  186 ,  188  from breaking or separating from the support  30 . Of course, a similar operation may be performed when the wheelchair-bound user  12  is on the platform  22  and wishes to descend to the floor  60 . In this case, actuation that lowers the platform  22  may cease when the processor  208  receives an electrical signal from the sensor  142  on the bottom side  144  of the platform  22 . 
     Other safety or inhibit sensors may be provided as well—e.g., a load sensor  216  ( FIG. 6 ) may be carried by the base  100  and coupled to the control circuit  206 . In general, this sensor may be used to identify that a user is on the platform  22  and inhibit undesirable platform movement. Consider for example when the lower call switch  62  is actuated while a wheelchair user  12  is on the platform  22  at the landing  58 . The load sensor  216  may sense the wheelchair-bound user&#39;s  12  presence on the platform  22  and send an electrical signal to the control circuit  216 , which may ignore call switch actuation. 
     In another example, an inhibit sensor  218  ( FIG. 6 ) may be carried by the platform  22  to detect an obstruction on the stairway  18  at a time when the call switch  62  is actuated; e.g., the inhibit sensor  218  may be used to prevent the platform  22  from colliding with the obstruction. A non-limiting example of the inhibit sensor includes a laser emitter and detector  218  that seeks a laser return (mounted on the platform  22 ) and a reflector  220  mounted on the stand  20  (aligned with the laser). The processor  208  may receive no inhibit signal from the sensor  218  when the transmitted laser receives a return signal; however, if no return signal is received at the sensor  218 , then the inhibit sensor  218  may provide a wired or wireless signal to the processor  208  and the processor  208  may inhibit movement of the platform  22  until the obstruction is cleared from the stairway path. 
     Another sensor may include a power-level sensor  222  ( FIG. 6 ) coupled to the control circuit  206  and a power-level indicator  224  (shown in  FIG. 5 ). For example, the power-level sensor  222  may sense a low voltage or low power condition associated with the platform power source  182 , and the indicator  224  may be any suitable visual, audible, or tactile indicator which may be located on one of the handrails  170 . In this manner, when the processor  208  receives an electrical signal from the power-level sensor  222  indicating a low voltage condition, the processor  208  may alert users of the lifting apparatus  10  via the indicator  224 . Further, according to one embodiment, the processor  208  may inhibit movement of the platform  22  during low voltage conditions. According to another embodiment, if the processor  208  detects a low power condition, the platform  22  may be returned to the lower position  14  (floor) and may not be powered until the low power condition ceases (e.g., the battery is charged or replaced). 
     Some implementations of the lift apparatus  10  may include rechargeable power source cells. For example, when the lift apparatus  10  is adapted to outdoor use (e.g., outdoor stairs), the power source  182  may utilize solar cells to charge the power source. This of course is merely another example; other implementations are possible—including AC power implementations. In at least one embodiment, the power source  182  is DC power so that no electrical wiring between the platform  22  and the stand  20  is required and no electrical wiring between the environment (e.g., an AC wall outlet) and the platform  22  or stand  20  is required. 
     Still other implementations are possible using sensors. For example, a timer  230  of the control circuit  206  ( FIG. 9 ) may send the platform  22  to the floor  60  automatically after a predetermined period of time has passed. For example, using the platform position sensor  214  ( FIG. 6 ), the processor  208  may determine the location of the platform  22  with respect to the stand  20 . If the position sensor  214  indicates that the platform  22  is located somewhere other than the lower position  14  and the predetermined period of time has expired with the platform  22  is in that position, then the platform  22  may be returned automatically to the lower position  14 —controlled by the processor  208 . In this manner, foot traffic may not be obstructed by the platform  22  remaining in the upper position  16  for long durations of time. 
     At least one embodiment of the wheelchair lift assist  10  includes a portable loading ramp  240 , as shown in  FIG. 1 . The ramp  240  may provide a smooth transition for ingressing and egressing onto the platform  22  from the floor  60 —e.g., particularly in implementations where the upper surface of the platform&#39;s base  100  is more than an inch above the floor  60 . According to some embodiments, the loading ramp  240  may have any suitable width, a height between 1 and 5 inches, and a length of between 3 and 6 feet. In some implementations, the ramp  240  is coupled to the lower support  28  or the platform  22 ; however, this is not required. It should be appreciated that embodiments exist with and without the loading ramp  240 . 
     Other embodiments of the wheelchair lift apparatus  10  also exist. For example, the trolleys  150  could be motorized to move the platform  22  up and down along the guide rails—e.g., a cable-less system. Any suitable means could be provided to enable the platform  22  to ascend and descend the stand  20 . For example, the guide rails could have teeth that mesh with a motorized trolley gear. Other features may be generally similar to those described above—e.g., enabling the wheelchair-bound individual  12  to similarly use the lift apparatus  10  while also enabling non-wheelchair-bound individuals to walk up and down the stairway  18 . 
     According to another embodiment of the lift apparatus  10 , three or more supports may be used. For example, as shown in  FIG. 6 , a third or middle support  242  may be used. This may be suitable for some longer stairways. 
     At least some implementations described herein may utilize the processor  208  and memory  210 . The processor  208  described herein may be any type of device capable of processing electronic instructions, non-limiting examples including a microprocessor, microcontroller, host processor, controller, vehicle communication processor, and an application specific integrated circuit (ASIC). Processor executes digitally-stored instructions, which may be stored in memory, which enable the control circuit to perform one or more wheelchair lift functions. 
     Memory  210  may include any non-transitory computer usable or readable medium, which include one or more storage devices or articles. Exemplary non-transitory computer usable storage devices include conventional computer system RAM (random access memory), ROM (read only memory), EPROM (erasable, programmable ROM), EEPROM (electrically erasable, programmable ROM), and magnetic or optical disks or tapes. As discussed above, memory  210  may store one or more computer program products which may be embodied as software and/or firmware. For example, memory may store instructions which enable the control circuit  206  to facilitate at least a portion of the method described herein. 
     Thus, there has been described a wheelchair lift apparatus that enables wheelchair-bound individuals to traverse between a floor and an elevated landing—e.g., over various obstacles. In one embodiment, the apparatus carries a wheelchair-bound individual up and down stairways. When the apparatus is not being used, the stairway is usable by non-wheelchair-bound individuals—e.g., foot traffic. In general, the apparatus may be portable and installable without needing to be fixed to existing structures or the stairway itself. The apparatus includes a stand and a mobilized platform adapted to carry the wheelchair-bound individual safely between the floor and landing. 
     It is to be understood that the foregoing is a description of one or more embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims. 
     As used in this specification and claims, the terms “e.g.,” “for example,” “for instance,” “such as,” and “like,” and the verbs “comprising,” “having,” “including,” and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.