Abstract:
The invention is a device for securing a wheelchair to a vehicle. The invention incorporates a pair of belts disposed near a wheelchair station in a vehicle, the belts being remotely operable between tension and release positions. When not in use, the belts are stowed in compartments beside and underneath the floor of the vehicle to eliminate potential obstacles. The rear of the wheelchair is secured to the vehicle using remotely lockable anchor elements which are also retractable when the wheelchair station is not in use.

Description:
RELATED APPLICATIONS 
     This application is related to, and claims the benefit of priority from, U.S. Provisional Patent Application Ser. No. 60/292,748, filed May 21, 2001. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to devices for securing a wheelchair to a vehicle. In particular, the invention includes a system utilizing stowable webbed belts and utilizing a power system for providing tension on said belts. 
     BACKGROUND 
     In recent years, it has become a commonplace to provide wheelchair users with accommodations in mass transit vehicles, such as buses, trains or airplanes. Such accommodations typically allow these persons to ride in the vehicle while remaining in the wheelchair. It is desirable, under these circumstances, to secure the occupant and the wheelchair to the vehicle for the safety of the user of the wheelchair, as well as the safety of other occupants of the vehicle. 
     While numerous methodologies have been developed for securing wheelchairs to the interior of vehicles, many of the methods and devices developed for such securement create inconveniences to both the wheelchair passenger and the operator of the vehicle. Because the wheelchair-using passenger is frequently restricted in body movement, it is desirable to provide wheelchair securement systems which are easily reached and manipulated by the passenger. In the alternative, if such securement systems are not manipulative solely by the passenger, it is desirable to have them easily operable by the vehicle operator or an operator&#39;s assistant. It is also desirable to provide wheelchair securement systems which are easily repositioned within the vehicle to permit the space sometimes used by a wheelchair-using passenger to be readily converted for use by persons not so handicapped. For this reason, a wide variety of methodologies and devices have been developed in the form of stowable restraints for wheelchairs and wheelchair-using passengers. Preferably, such restraints should be positioned in the immediate vicinity of the area where a wheelchair will be secured. In known systems using a plurality of belts and anchors, however, (belts and anchors which are stowed remotely, for example, in a storage locker), such belts and anchors frequently become lost, damaged or soiled when not in use. Additionally, this type of restraint almost always requires installation in the vehicle and attachment to the wheelchair by someone other than the wheelchair occupant. 
     It is also known to provide wheelchair restraint systems which are secured to the vehicle and articulate between a stowed and an extended position. This type of technology is found in U.S. Pat. No. 5,888,038, issued to Ditch et al.; U.S. Pat. No. 6,113,325, issued to Craft. Even these systems, however, have an important drawback in that it is difficult to provide the necessary securement and tension to four discrete points on the wheelchair, in the fashion in which the anchoring apparatus for the wheelchair is usually attached to the vehicle, without the assistance of a person other than the wheelchair occupant. Existing systems are also awkward to use and store. 
     There is a need, therefore, for a wheelchair tie-down system which is easily attached to the wheelchair by the vehicle operator or the wheelchair occupant alone, which is similarly easy to tension, and which is readily stowable within the vehicle, eliminating the presence of any obstacles to other passengers when the system is not in use. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, a simple-to-use, easily installed tie-down system for wheelchairs is provided. The system is installed in public transportation vehicles in such a fashion as to present no obstacle to the traveling public when the system is not in use, but yet is readily available for operation when needed by a wheelchair-using passenger. The system allows the same space in a vehicle to be used, alternatively, by wheelchair-using passengers and by ambulatory passengers. In one embodiment, the components of the tie-down system are located in an area of the bus which may also be occupied by foldable chairs usable by ambulatory passengers. Preferably, these chairs may be readily moved away from the area to be occupied by a wheelchair-using passenger, and just as easily repositioned for conventional use as desired. 
     The system comprises a front tensioning assembly and one or more rear anchoring assemblies located in proximity to a wheelchair station. The tensioning and anchoring assemblies are mounted to the floor and walls of the vehicle in such a fashion as to provide the necessary security to restrain the wheelchair from movement during normal transit and in the event of a collision involving the vehicle. The tensioning elements of the system are provided with locking means, power-driven tensioning means as well as feedback means, to impart an appropriate amount of tension to the tensioning elements automatically. Manual tensioning means may also be provided. 
     In use by a wheelchair occupant, the system includes a front tensioning assembly having a cooperating pair of webbed belts which are provided with hooks to engage the front framework of a wheelchair. The belts are arranged in relationship to a front housing and front guide in such a fashion as to provide laterally spaced positions for the hooks and belts, thereby insuring that both the right front and left front portions of a wheelchair will be suitably engaged to restrict both longitudinal and lateral movement of the front of the wheelchair in relation to the vehicle. The front tensioning assembly also features a covered enclosure portion in which the inboard front belt and hook can be stowed when the tensioning system is not in use. This enclosure is designed with an extremely low profile, thereby presenting no obstacle to other passengers when the system is not in use by a wheelchair-using passenger. In one embodiment, one or more rear anchor assemblies are provided behind the wheelchair station in the vehicle, aft of the front tensioning assembly in such a fashion as to permit one or more hooks and belts from rear anchor assemblies to engage one or more portions of the rear of a wheelchair. Preferably, there are two cooperating rear anchor assemblies, one located near the inboard part of the wheelchair station and one located near the outboard part of the wheelchair station. These rear anchoring assemblies provide securement of the wheelchair from forward movement as well as from lateral movement. 
     In operation, the front tensioning belts and rear anchoring belts and their associated hooks are affixed to the four corner areas of the wheelchair and placed under tension securing the wheelchair from fore and aft or lateral movement. 
     One feature of the present invention is the utilization of power-driven means, preferably electrical, to provide tension to at least some of the tensioning belts, and feedback means to ascertain when the belts have been placed under suitable tension. These tensioning and feedback means are preferably automatic and fail-safe. 
     It is an object of this invention to provide a convenient tie-down system for a wheelchair passenger utilizing a motor vehicle having a wheelchair station. 
     It is a further object of this invention to provide a tie-down system which is easily utilized by the wheelchair occupant without the assistance of others, or which is convenient to use by a person assisting the wheelchair occupant. 
     Another object of this invention is to provide a wheelchair tie-down system having a powered tensioning means, thereby permitting appropriate tension to be supplied for securing the wheelchair in position in the vehicle without the need for manually tensioning of the securing belts. 
     Still another object of this invention is a wheelchair restraint system which is readily convertible to a stowed configuration, thereby minimizing obstruction or inconvenience of ambulatory passengers. 
     It is a further object of the invention to provide a wheelchair restraint system which is not subject to being misplaced, soiled or damaged, and which does not require complicated installation steps prior to each use. 
     These and other objects of the invention will be apparent from a review of the detailed description of the preferred embodiment, and from the drawings and claims which follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the elements of the present invention in a typical vehicle environment. 
         FIG. 2  is a perspective view of the main elements of the invention in a typical vehicle environment. 
         FIG. 3  is a top view of the front tensioning assembly. 
         FIG. 4  is an elevation view of the front tensioning assembly showing the belts in the extended position. 
         FIG. 5  is a side view of the front tensioning assembly viewed from the inboard side. 
         FIG. 6  is a top view of the front tensioning assembly showing the belts and hooks in the stowed position. 
         FIG. 7  is an elevation view of the front tensioning assembly, showing the belts in the stowed position. 
         FIG. 8  is a side view of the front tensioning assembly, showing a stowed belt and hook, viewed from the inboard side. 
         FIG. 9  is a perspective view of the control box. 
         FIG. 10  is a perspective view of electrically powered rear tensioning elements. 
         FIG. 11  is a perspective view of manually operable rear tensioning elements. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference first to  FIG. 1 , a wheelchair station  100  is provided in a vehicle having a floor  104  and one or more side walls  102 . The wheelchair station is located between a front tensioning assembly  12  and one or more rear tensioning assemblies  14 . A control system  60  is provided for providing tension to the front tensioning assembly  12  and rear tensioning assemblies  14 . Together, the tensioning assemblies, with the associated controls and wiring constitutes the system  10  of the invention, designed to secure wheelchair  11  and its occupant to the station  100 . 
     With reference now to  FIGS. 1–9 , the detailed elements of the front tensioning assembly  12  will be better understood. To provide suitable elements for securing and tensioning the front portion of a wheelchair  11 , front tensioning assembly  12  comprises a front floor plate  44  secured to the floor  104  of a vehicle utilizing fasteners  54  which may be screws, rivets, bolts, or other well-known fastening means. The front floor plate  44  includes an enclosure portion  48 , beveled edges  46 , and cover plate  50  which is movable between an open position as shown in  FIG. 3  and a closed position as shown in  FIG. 6 . Associated with front tensioning assembly  12  is a pair of tensioning belts, front outboard belt  16  and front inboard belt  18 , both of which are provided with wheelchair-engaging hooks  34  attached to belts  16  and  18  by outboard belt loop  35  and inboard belt loop  37 . Belts  16  and  18  are routed through belt guides  38  and  40  respectively. Belt guide  40  is attached to pivot assembly  42 . Pivot assembly  42  is hinged at hinge point  49  permitting pivot assembly  42  to articulate through angle ⊖. Belt guide  40  is attached to pivot assembly  42  through pivot pin  51 , thereby allowing belt guide  40  to rotate around the axis of pivot pin  51 . In this fashion, belt  18  and belt guide  40  and pivot assembly  42  may be rotated into appropriate orientation for stowing the hook  34 , belt  18 , belt guide  40  and pivot assembly  42  underneath cover plate  50  when cover plate  50  is in the closed position as shown in  FIG. 6 . Preferably, the position of belt guide  40 , belt  18  and belt hook  34  are located on the opposite end of front floor plate  44  from belt guide  38 , and belt  16 . This positioning insures that lateral support is provided to the front of the wheelchair  11  by belts  16  and  18  and their associated hooks  34 . 
     As shown best in  FIG. 4 , a pivoting outboard belt guide  38  is affixed to front drive housing  28 , which is in turn affixed to front floor plate  44 . It will be appreciated that front floor plate  44  and front drive housing  28  will be attached to the floor  104  of the vehicle using appropriate fasteners  54  to insure that the front tensioning assembly  12  provides the necessary support to restrain the wheelchair  11  from movement in the event of a collision. The front drive housing  28  is provided with a hanger  36  adapted to support the hook  34  affixed to front outboard belt  16  when the front tensioning assembly  12  is not in use. 
     Preferably, the front floor plate  44  is provided with beveled edges  46  and cover plate  50 , which, when the system is in its stowed or retracted position, provides a relatively smooth and unimpeding surface for other passengers to walk over without tripping. With further reference to  FIGS. 1 ,  3  and  4 , it will be appreciated that the configuration therein displayed is typical of the configuration in which the front tensioning assembly  12  would appear when in use. The two hooks  34  appear in the position that they would occupy if engaged with the front portion of a wheelchair  11 . Under these circumstances, belts  16  and  18  extend from one or more storage reels located within drive housing  28 . Sufficient belt webbing is provided for belt  16  and  18  to insure that they may be extended and retracted to accommodate a wide range of wheelchair styles and sizes. Within housing  28  is a roller guide (not shown) which guides belts  18  and  16  onto one or more storage reels (not shown) to prevent belts  16  and  18  from fouling or jamming during extension and retraction from and to the belt reel within housing  28 . Cover plate  50  preferably slides over opening  53 . The edges of cover plate  50  engage the edges of opening  53  in a secure fashion to prevent cover plate  50  from lifting upward away from front floor plate  44 , or from downward movement into belt enclosure portion  48  through opening  53 . This result may be easily accomplished by providing a tongue and groove-type engagement between the edges of opening  53  and cover plate  50 . Cover plate  50  may also be provided with additional guides and rollers (not shown) to provide a low friction guiding action to that portion of belt  18  which passes through the belt enclosure portion  48 . 
     In use, cover plate  50  is slid to the retracted position shown in  FIG. 3 , exposing belt guide  40 , pivot assembly  42 , belt  18  and belt hook  34 . Likewise, belt  16  and belt hook  34  are removed from their stowed position on hanger  36  and attached to the wheelchair  11  in the approximate orientation shown in  FIG. 1 .  FIG. 5  shows a typical orientation of belt guide  40  and belt guide  38 , with belts  16  and belt  18  removed for clarity. 
     With reference now to  FIG. 1 , as well as to  FIG. 4 , it will be easily understood that tension may be applied to belts  16  and  18 , thereby drawing those portions of belts  16  and  18  located between hooks  34  and guides  38  and  40  closer to guides  38  and  40 , thereby tending to pull a wheelchair  11  affixed to hooks  34  in a forward direction. Assuming that the rear of the wheelchair  11  is secured from the rear, belts  16  and  18  will thereby provide tension to secure the wheelchair  11  from both forward and aft and lateral movement. In one embodiment, this tension is provided by front tension motor assembly  24  which is operatively coupled to a drive mechanism (not shown) located within front drive housing  28 . In this embodiment, a simple gear train provides a speed reduction for motor assembly  24  and a corresponding increase in mechanical advantage to the belt storage reels contained within front drive housing  28 . Motor  24  is operative in both clockwise and counter-clockwise directions, permitting tension on belts  16  and  18  to be selectively applied and released. 
     Although the preferred embodiment contemplates the use of electrical power as the motor driving source, it will be obvious to those skilled in the art that other power sources, such as pneumatic or hydraulic power may be used for motor  24 . Further, as shown in  FIGS. 1 and 3 , belts  16  and  18  may be operated from separate storage reels driven by a common motor assembly  24  utilizing the necessary separate drive gear trains within housing  28 . It can also be appreciated from  FIG. 3  and  FIG. 5  that manual tensioning screws  56  may be provided to manually drive the necessary gear trains within housing  28  to manually tighten or loosen the belts  16  and  18  when not using a powered system or in the event of a power failure in the system. It will also be appreciated that it is beneficial to provide a drain  52  in floor plate  44  to permit water and debris which may collect within the belt enclosure portion  48  to be removed from the vehicle. 
     With reference now to  FIGS. 2 ,  6  and  7 , the stowed position of the front tensioning assembly belts will be easily understood. By providing sufficient tension to belts  16  and  18 , belts  16  and  18  and their associated hooks  34  are drawn toward belt guides  38  and  40 . When fully retracted, inboard belt hook  34  is stowed on hanger  36 , and belt  18  and its associated hook  34  are stowed within belt enclosure portion  48 . Cover plate  50  is slidably moved to cover opening  53  which will enclose both belt  18  and its associated hook  34 . Passengers in the vehicle are then presented with a relatively flat and unimpeding surface comprising front floor plate  44  and cover plate  50 . 
     With reference now to  FIGS. 1 and 2 , the orientation, mounting and operation of rear tensioning assemblies will be better understood. In the preferred embodiment, two rear tensioning assemblies  14  are provided with belts  20  and hooks  34 . Again, it is desirable to locate one rear tensioning assembly  14  near the right rear of the wheelchair station  100  and one near the left rear of the wheelchair station  100 , separated by sufficient distance to provide lateral support to the wheelchair  11  when the tensioning assemblies  14  are under tension. Within each rear tensioning assembly housing  30  is a spring biased reel adapted to spool and provide selective tension to belts  20 . Preferably, belts  20  can be extended or retracted selectively by pulling on or releasing tension from said belts. Again, hooks  34  are affixed to belts  20  by loops sewn in the ends of belts  20 . 
     As shown in  FIGS. 10 and 11 , each rear tensioning assembly  14  is provided with a belt  20  and a spring biased reel (not shown) within a housing  30  and cooperating with the belt  20 . Each rear tensioning assembly is affixed to the vehicle using fasteners, such as nuts  110  washers  111  and bolts  112 , suitable for securing each rear tensioning assembly  14  to a suitable anchor point  114  on the vehicle. In one embodiment, this attachment point may be the support for a modesty panel  130   130  or seat frame. The rear tensioning assemblies  14  are provided with a selective release mechanism  116  cooperating with the spring biased reel inside housing  30 . In this embodiment, the selective release mechanism  116  is secured to the rear tensioning assembly  14 . A pawl within the selective release mechanism  116  may be selectively engaged with a portion of the spring biased reel, selectively preventing or allowing movement of the spring biased reel. Operation of the pawl within the selective release mechanism  116  is regulated by a flexible cable assembly  118 . The distal end of each flexible cable assembly  118  engages a cable actuator assembly  120 ,  121 . Cable actuator assembly  120 ,  121  may be provided with power means, or may be operated manually. Operation of the cable actuator assembly  120 ,  121  applies or releases tension from cable assemblies  118 , thereby selectively applying or releasing tension to the selective release mechanism  116  associated with each rear tensioning assembly  14 . The cable actuator assembly  120 ,  121  has a “locked” and a “release” position. When the cable actuator assembly  120 ,  121  is operated to the “lock” position, no tension is supplied to the cable assemblies  118 , thereby allowing the pawl within the selective release mechanism  116  to be in its normally locked position, and preventing the spring biased reel within assembly  14  from movement. Operation of the cable actuator assembly  120 ,  121  to the “release” position applies tension on the cable assemblies  118 , causing the pawl within the selective release mechanism  116  to be withdrawn from engagement with the spring biased reel, thereby permitting the belt  20  to be extended or withdrawn into the housing  30  of the rear tensioning assembly  14 . 
     The basic operation of the system is shown in  FIG. 1  and  FIG. 9 , which includes a simplified and stylized view of both a front tensioning assembly  12 , two rear anchor assemblies  14  and a control box  60 . In the preferred embodiment control box  60  includes both a means for providing an operating signal such as a drive circuit  66  and a means for measuring tension such as a sensing or feedback circuit  67 . The front tensioning assembly  12  is provided with an electric motor assembly  24 , in the present embodiment, to provide rotational motion and the necessary torque to tension and relax the belts. It will be readily understood that providing electrical power and controls to such electric motor assemblies is a task easily accomplished by a micro controller  65  with associated circuitry. Cooperating with the drive motor circuit  66  is a sensing circuit  67  which is designed as a means for measuring the amount of current being drawn by the electric motor in the invention. Drive motor current is known to be directly proportional to the motor torque, which in turn, is directly proportional to applied belt tension. It is known that when a desired belt tension is reached that the desired current level is also presented to the motor drive circuit  66 . Referring to  FIG. 9 , a micro controller unit  65  within the control box  60  is preprogrammed to sense this desired current level, and to turn off the drive motor when this current level has been reached. The micro control unit  65  is completely automatic, and will continue to sample the tension on the belts  16  and  18  when the system is in operation. When the micro controller unit  65  determines that the belts  16  and  18  are appropriately tensioned, it will provide a signal in the form of indicator lights  68  which will visually confirm for the wheelchair occupant or vehicle operator that the wheelchair  11  is secured. The control box  60  is provided with a two-position selector switch  62 . In one position, the system is configured for tensioning of the belts  16  and  18 . In the other position, the system is configured for release of the belts  16  and  18 . After selecting the desired operation, (tension or release) the start switch  64  is utilized to energize the circuit and provide the necessary drive signals to the tensioning motor. In the tension mode, if for some reason one or more belts  16  and  18  are not tensioned, means for indicating the condition of the operating signal such as the two indicator lights  68  will illuminate simultaneously indicating that the system has malfunctioned. The circuit is provided with means for electronically varying the amount of tension, such as potentiometers  69  for adjustments which allows the circuit to be easily calibrated for different belt tensions. In one embodiment, motor assembly  24  contains two separate motors. Separate drive circuits for each motor permit each belt  16  and  18  to be calibrated in such a way as to be tensioned independently from each other belt. 
     In operation, therefore, once the wheelchair  11  has been positioned in the station, the wheelchair occupant or the vehicle operator operates the system to release tension and unstow each of the belts from their retracted position and attach each associated hook to the appropriate corner portion of the wheelchair. If a manual cable actuator  120  is included with the system, the wheelchair occupant or vehicle operator will move the cable actuator control handle  124  to the “lock” position, thereby restricting the rear belts  20  from further extension from their respective housings  30 . If a power cable actuator  121  is included with the system, actuation of the selector switch  62  to the tension position locks the selective release mechanisms  116 . Once the four belts have been so positioned, the wheelchair occupant or vehicle operator will position the switch  62  to the tension position and operate switch  64 . This operation sets into motion the automatic tensioning and feedback logic contained within the controller unit, sending a “lock” signal to an electronically powered cable actuator assembly  120 , driving the appropriate belt tensioning motors of motor assembly  24  to their desired tensions, thereby securing the wheelchair  11  from both fore and aft and lateral movement within the vehicle. Power to the motors is then removed, effectively locking the tensioning belts  16  and  18  in their desired tensioned position. 
     Release of the wheelchair from the wheelchair station is accomplished by moving the switch  62  to the “release” position and operating the start switch  64  which results in a release of the tension on all belts, as a result of driving the motor  24  associated with the tensioning assembly  12  in the reverse direction from the tensioning direction. As soon as sufficient slack has been created in the belt tensioning system, the motors of motor assembly  24  are automatically de-energized, allowing the hooks  34  and belts  16  and  18  to be released from the wheelchair. If the system is equipped with a power cable actuator assembly  121 , at the same time, the cable actuator assembly  121  is provided with a “release” signal, actuating the selective release mechanism  116  to permit the rear belts  20  to be extended from and retracted into their housings  30 . If the system is equipped with a manual cable actuator assembly  120 , the wheelchair occupant or vehicle operator will release the manual release handle  124  to accomplish the same result. Once the hooks  34  and belts  20 ,  16  and  18  have been released from the wheelchair, the switch  62  is again moved to the “tension” position and the start switch  64  operated. Stops built into the rear anchor assembly housing  30  prevents hooks  34  from retracting into the housing. Hanger  36  secures the hook  34  associated with belt  16  from retracting into guide  38 . Guide  40  prevents hook  34  from excess movement. Accordingly, operation of the start switch  24  when a wheelchair  11  is no longer located in the wheelchair station  100  results in application of tension to the front belts  16  and  18  to place them in their fully retracted position. Once belt  18  is fully retracted, cover plate  50  can be positioned over opening  53 , thereby completing the stowing process. 
     Another aspect of the system shown in  FIG. 1  is the provision for standard occupant restraints in association with the invention to insure that a wheelchair occupant remains restrained in the wheelchair  11  being secured to the vehicle according to the present invention, in the form of conventional seat belt elements  145 ,  142  and  148 . A quick release buckle  150  allows for securement and release of these conventional seat belt elements in relation to the passenger.