Patent Publication Number: US-6698998-B2

Title: Foldable ramp

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to passenger and wheelchair ramps and more particularly to a wheelchair ramp mountable in a low floor height vehicle and foldable for convenient storage in the vehicle. The device is unfolded to provide a ramp for wheelchairs and passengers to access the vehicle. 
     BACKGROUND OF THE INVENTION 
     There has been an increasing interest in developing automated devices to facilitate the mobility of people who have difficulty walking. Although various forms of wheelchairs have helped considerably, their users face many obstacles, such as getting in and out of vehicles like vans and buses. Wheelchair ramps are used to assist in the loading and unloading of passengers from vans, buses and other such vehicles. However, available ramps are often bulky and cumbersome. When bulky ramps are installed in vehicles, the components of the vehicle must be rearranged to accommodate the sizable ramps. For example, when known ramps are installed in a bus, typically, the chassis rail of the bus must be partially cut to receive the ramp. Furthermore, the fare box may have to be repositioned to accommodate the ramp. In some buses, passenger seats are removed to allow additional room for the housing and operation of the ramps. Consequently, there is a need for new passenger ramps that are compact and capable of being installed in a vehicle without requiring the components of the vehicle to be rearranged. Yet, the ramp must be large enough and sufficiently durable to support the combined weight of a wheelchair and a person thereon during the loading and unloading process. 
     SUMMARY OF THE INVENTION 
     A foldable wheelchair ramp is disclosed having a mountable base, a first ramp section and a second ramp section. In an extended configuration, the first and second ramp sections form a single, continuous ramp for facilitating wheelchair access to a vehicle. For convenient storage, the first and second ramp sections fold with respect to each other and preferably retract into the vehicle floor such that, in the folded configuration, the top surface of the second ramp section lies substantially in the same plane as the vehicle floor. 
     A linking assembly is provided to facilitate and control the folding and unfolding of the ramp sections based on the movement of the deployment mechanism. In a preferred embodiment of the invention, the linking assembly includes a driving arm, a driven arm and a fold facilitating arm. The driving arm can be hydraulically, electrically or pneumatically powered. The driven arm is preferably pivotably connected to the driving arm and causes the first ramp section to rotate toward the base during the folding process. The driven arm is also pivotably connected to the fold facilitating arm, which causes the second ramp section to pivot and fold with respect to the first ramp section. When the ramp is in a fully folded configuration, the bottom surfaces of the ramp sections are preferably positioned in a facing relationship to each other and the linking assembly is stored in a storage area below the plane of the vehicle floor. 
     For safety purposes, the ramp also includes a lid that covers the empty storage area when the linking assembly has moved out of the storage area. The lid is preferably biased in an open position to allow the linking assembly access to the storage area during folding. To close the lid, a closing spring preferably connects the lid to a support member. When the ramp is extended outward, the driving arm preferably contacts the support member, causing the support member to pivot and the spring to pull the lid into a closed position. 
     Other objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description. It is to be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not limitation. Many changes and modifications within the scope of the present invention may be made without departing from the spirit thereof, and the invention includes all such modifications. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention may be more readily understood by referring to the accompanying drawings in which: 
     FIG. 1 a preferred embodiment of the foldable ramp of the present invention as installed in a bus; 
     FIG. 2 is a perspective view of a preferred embodiment of the foldable ramp of the present invention with the base cover removed to show the driving mechanism of the ramp; 
     FIG. 3 is a perspective view of a preferred embodiment of the foldable ramp of the present invention during the folding process; 
     FIG. 4 is another perspective view of a preferred embodiment of the foldable ramp of the present invention during the folding process; 
     FIG. 5 is a perspective view of a preferred embodiment of the foldable ramp of the present invention in a fully folded, storage configuration; 
     FIG. 6 is a side view of a preferred embodiment of the guide and wheel engagement that controls the folding movement of the ramp of the present invention; 
     FIGS. 7A through 7D are side views of a preferred embodiment of the foldable ramp of the present invention, showing the movement of the storage area lid as the linkage assembly moves in and out of the storage area; and 
     FIG. 8 is a perspective view of a preferred embodiment of the driving arm camming against the support member. 
    
    
     Like numerals refer to like parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 depicts a preferred embodiment of the foldable ramp  10  of the present invention that is mountable in a vehicle  2  to facilitate the ingress and egress of a wheelchair and its occupant. In a preferred embodiment, the foldable ramp  10  is mounted on the vehicle floor  6  near the side doorway  4 . The foldable ramp can also be mounted near the rear door or any other door of a vehicle. The preferred vehicle for use with the ramp of the present invention is a van, bus or other low floor height vehicle. 
     As best shown in FIGS. 1 and 2, a preferred embodiment of the foldable ramp  10  of the present invention includes a mountable base  12 , a first ramp section  14  and a second ramp section  16 . The mountable base  12  is preferably installed in the vehicle floor  6  and, in an extended configuration, first and second ramp sections  14  and  16  form an inclined ramp, and the distal edge  28  of the second ramp section  16  meets the ground thereby facilitating the ingress and egress of a wheelchair and its occupant on and off the vehicle. 
     In an extended configuration, the first ramp section  14  has a first edge  22  located proximal the mountable base  12  and a second opposing edge  24  located distal the mountable base  12 . The second ramp section  16  has a first edge  26  pivotably connected to the second edge  24  of the first ramp section  14 . In one embodiment of the invention, the first and second ramp sections  14  and  16  are pivotably connected using a hinge  20 . However, it is within the scope of the invention to use other pivoting devices known in the art to pivotably connect the second edge  24  of the first ramp section  14  to the first edge  26  of the second ramp section  16 . 
     Referring to FIG. 2, the interior of the mounting base  12  is shown without a top cover plate. The mounting base  12  preferably houses the driving mechanism  30  for actuating the ramp sections  14  and  16  from a folded, stowed configuration to a fully extended configuration. For ease of operation, the driving mechanism  30  can be powered by electrical, hydraulic, or pneumatic means, or other source of energy known to those skilled in the art. 
     In a preferred embodiment of the invention, the driving mechanism  30  includes an actuator  32  and a driving shaft  34 . The driving shaft  34  extends to the sides  18  of the mountable base and is secured thereto by mounting brackets  36 . The actuator  32  may be rotary or linear. In the embodiment shown in FIG. 2, the actuator  32  used is a rotary actuator commercially available from Micro-Precision Textron and is installed in the mountable base  12 . The rotary actuator shown is preferably hydraulically driven and as such, is connected to a hydraulic control unit and hydraulic lines (not shown). The actuator  32  may also be driven by electrical, pneumatic or other energy means. 
     In a preferred embodiment of the invention, as shown in FIGS. 2 through 6, the driving shaft  34  drives a pair of linkage assemblies  50  to fold ramp  10  into a storage configuration (as shown in FIG. 5) and thereafter, unfold the ramp into a fully extended ramp configuration (as shown in FIG.  2 ). For ease of understanding, only the left linkage assembly  50  will be described in detail and it should be understood that the right linkage assembly is a mirror image of the left linkage assembly. The linkage assembly  50  includes a driving arm  60 , a driven arm  70  and a fold facilitating arm  80 . A first end  62  of the driving arm  60  is operatively connected to the driving shaft  34 . Upon actuation of the driving shaft  34  by actuator  32 , force is exerted on the driving arm  60  causing the driving arm  60  to rotate in the same direction as the driving shaft  34 . The second end  64  of the driving arm  60  is pivotably connected to a first end  72  of the driven arm  70 . The driven arm  70  is preferably pivotably connected to the first ramp section  14  at a connection point  74 . 
     When operating the ramp  10  from a fully extended ramp configuration to a folded storage configuration, the driving shaft  34  rotates in the direction designated as F in FIG. 2, causing the driving arm  60  to also rotate in the direction F about the driving shaft  34 . As the driving shaft  34  and the driving arm  60  rotate in the direction F, the top surface  52  of the first ramp section  14  moves closer to the top surface  54  of the mountable base  12  (as shown in FIGS.  3  and  4 ). When the ramp  10  is in a folded storage configuration, shown in FIG. 5, the top surface  52  of the first ramp section  14  is in a substantially parallel, facing relationship with the top surface  54  of the mountable base  12 . Also, during the folding process, the driving arm  60  and driven arm  70  move closer to each other, ending in a folded state (as shown in FIG. 5) when the ramp is in a folded storage configuration. 
     Referring to FIGS. 2 through 5, the movement of the second ramp section  16  is now described. In a fully extended configuration, the first ramp section  14  and second ramp section  16  form a single, continuous inclined ramp for providing wheelchair access to and from vehicles. During the folding process, the fold facilitating link  80  causes the second ramp section  16  to pivot with respect to the first ramp section  14  and the bottom surface  58  of the second ramp section  16  moves closer to the bottom surface  56  of the first ramp section  14 . When the ramp  10  is in a folded storage configuration, shown in FIG. 5, the bottom surface  56  of the first ramp section  14  is in a substantially parallel, facing relationship with the bottom surface  58  of the second ramp section  16 . Also, during the folding process, the driven arm  70  and fold facilitating arm  80  move closer to each other, ending in a folded state when the ramp is in a folded storage configuration. 
     In a preferred embodiment of the invention, a first end  82  of the fold facilitating link  80  is pivotably connected to a second end  76  of the driven arm  70  and the second end  84  of the fold facilitating link  80  preferably includes a wheel  88  adapted to engage a guide  90  on the second ramp section  16 . As shown in FIG. 6, guide  90  preferably has a length  92  that is longer than the radius of the wheel  88 , allowing the wheel space to move back and forth in the guide  90  from the first end  94  to the second end  96  of the guide. The ability of the fold facilitating arm  80  to move with respect to the second ramp section  16  enables the second ramp section to pivot and fold with respect to the first ramp section  14 . 
     In a fully extended configuration (as shown in FIG.  2 ), wheel  88  is positioned at a first end  94  of the guide  90 . In a preferred embodiment of the invention, the guide  90  is slightly inclined upward in a direction toward the first ramp section  14 , as best shown in FIG.  6 . When the folding process begins, the driving shaft  34  rotates, causing the driving arm  60  to rotate about driving shaft  34 . Because the driving arm  60  is connected to the first ramp section  14 , the first ramp section  14  moves towards the mounting base  12 . The fold facilitating link  80 , together with the first edge  26  of the second ramp section  16  are raised with as the first ramp section  14  moves toward the mounting base  12 , while the second edge  28  of the second ramp section  16  is pulled downward by the force of gravity. As the first edge  26  of the second ramp section  16  is raised and the second edge  28  is lowered, the second ramp section  16  pivots and folds with respect to the first ramp section  14  and the bottom surface  58  of the second ramp section  16  moves closer to the bottom surface  56  of the first ramp section  14 . 
     In reference to FIG. 6, the movement of the wheel  88  in guide  90  is described. During the folding process, as the fold facilitating link  80  is raised, wheel  88  moves from the first end  94  of the guide  90  toward the second end  96 . By limiting the motion of the wheel  88  within guide  90 , the folding action is controlled. When the first ramp section  14  is substantially vertical, wheel  88  reaches the second end  96  of the guide  90 . As the first ramp section  14  moves from the substantially vertical position to the completely folded position, the wheel  88  again moves from the second end  96  of the guide  90  back to the first end  94 . In a fully folded storage configuration, wheel  88  rests against the first end  94  of the guide  90 . 
     It is within the scope of the invention to vary the shape and length of the guide  90  to control the folding movement of the ramp as desired. For example, in a preferred embodiment of the invention, the ends  94 ,  96  of guide  90  have a radius of curvature  98  that is greater than the radius of wheel  88  to facilitate smooth motion of the wheel  88  within the guide  90 . Other such modifications may be made without departing from the inventive concept disclosed herein. 
     As best shown in FIG. 7A, the driving arm  60 , driven arm  70  and at least part of the fold facilitating arm  80  preferably collapse in a storage area  100  when the ramp  10  is in a folded configuration. In a preferred embodiment of the invention, the storage area  100  is dimensioned to receive the linking assembly  50  so that the top surface  59  of the second ramp section  16  is substantially in the same plane as the vehicle floor  6  (shown in FIG.  1 ). When the ramp  10  unfolds, the linking assembly  50  expands and moves out of the storage area  100 . 
     The empty gap left in the storage area  100 , if uncovered, may pose a hazard to a person using the ramp. For example, if a part of a wheelchair becomes lodged in the storage area  100 , the wheelchair may topple, and the wheelchair occupant may be injured. Similarly, if a person&#39;s foot becomes lodged in the storage area  100 , the person may trip, fall and sustain injuries. Accordingly, in a preferred embodiment of the invention, a storage area lid  110  is provided to cover the storage area  100  when the ramp  10  is in an extended configuration. 
     The storage area lid  110  is preferably designed to automatically cover the storage area  100  as the ramp unfolds without the need of human intervention. As shown in FIGS. 7A through 7D and  8 , a preferred storage area lid  110  is biased in an open position by opening springs  112  or other known biasing devices. To facilitate the closing of the lid  110 , a closing spring  114  connects the lid to a first end  118  of a pivotable support member  116 . As the linking assembly  50  extends outwardly from the storage area  100 , the driving arm  60  contacts the support member  116  (as best shown in FIG.  8 ). The rotation of the driving arm  60  creates a camming action on the support member  116 , causing the support member  116  to pivot and the first end  118  of the support member to move in a downward direction. By pivoting, the support member  116  pulls the closing spring  114  until the biasing forces of the opening springs are overcome and the lid is forced downward to a closing position (as shown in FIG.  7 D). As a result, when the ramp is in a fully extended position, the empty storage area  100  is covered by the lid  110 . 
     When the ramp is again folded, lid  110  opens to allow the linking assembly  50  to enter the storage area  100 . During the folding process, the driving arm  60  rotates away from the support member  116 , causing the support member to pivot and the first end  118  of the support member  116  to move upward. As the tension on the closing spring  114  is released, the biasing force on the lid  110  causes the lid to open, thus allowing the linkage assembly access to the storage area. It is within the scope of the present invention to replace springs  112  and  114  with other types of springs or other types of biasing devices. 
     Those skilled in the art may now make numerous uses of, and departures from, the above-described embodiments without departing from the inventive concepts disclosed herein. Accordingly, the present invention is to be defined solely by the scope of the following claims.