Abstract:
The present invention is directed to a bi-folding wheelchair ( 10 ) with side frames ( 12 ) and ( 14 ) that fold together with a compound scissor action moving the large rear wheels ( 96 ) to a central location while the backrest ( 50 ) is folding downwardly. Two separate locking mechanisms ( 28 ) and ( 40 ) hold the frame apart in the upright position while two additional locking mechanisms ( 77 ) hold the backrest ( 50 ) upright or down in the collapsed position. All the major components of the conventional wheelchairs like the foot rests, the arm rests, large wheels, caster wheels and the backrest fit into a compact package narrower than the unfolded wheelchair and slightly larger than the diameter of the back wheels with all parts folding in and out simultaneously. The large rear wheel assemblies can be quickly removed further reducing the size and weight of the device for shipping or storage.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention is directed to the new design and improved convenience of the folding wheelchairs presently used by the handicapped. The multiple folding capabilities and dismantling features that come together in this design create as compact and lightweight wheelchair as possible. The novelty of this device is that all the major components of the conventional wheelchairs like the feet rests, the arm rests, wheels and back rest all fit into a compact package narrower than the existing wheelchair and slightly larger than the diameter of the back wheels with all parts fold in and out simultaneously. The device is locked in four separate places in the upright position and two places in the compact position. It can easily be handled by an elderly adult. 
       BACKGROUND OF THE INVENTION 
       [0002]    A significant number of the people are confined to move about in wheelchairs all or part of the time and face many challenges. While some of their problems are solved by the limited mobility afforded them through the wheelchair, other problems stem from the design, the weight and the amount of storage space required for conventional cumbersome wheelchairs. 
         [0003]    This invention relates to portable wheelchairs capable of folding or collapsing that have been in use for many years to accommodate wheelchair users who travel and need to take their wheelchairs with them or store them in space limited compartments. Typically, the wheelchairs that are designed to fold or collapse incorporate a pair of diagonally extending cross members, secured between a right and left frame member which scissor together to collapse the wheelchair sides. Although increasing the portability of the wheelchair, the typical cross member frame sacrifices strength and stability. Additionally, standard cross member frame construction for portable wheelchairs is bulky and heavy, making transportation or storage difficult at best. Consequently, portable wheelchairs have not been designed for easy storage in standard luggage compartments on airlines, small to medium sized automobiles, trains and other forms of transportation. 
         [0004]    Wheelchairs are generally designated as either “active” or “passive” depending upon how they are used. An active wheelchair is a wheelchair that is operated by the wheelchair user. Active wheelchairs generally have large rear wheels with a circular handgrip ring attached to the wheels. The wheelchair occupant propels the wheelchair himself by applying a force to the handgrip ring to turn the rear wheels. 
         [0005]    On the other hand, a passive wheelchair is designed to be pushed by an individual to transport the wheelchair occupant sitting in the wheelchair. These passive wheelchairs generally have much smaller rear wheels than the active wheelchair and usually include a bar attached to the back seat of the wheelchair for the individual to grip while pushing the passive wheelchair. 
       SUMMARY OF THE INVENTION 
       [0006]    This invention has the unique capability of folding in two separate directions at the same time with the foot rests attached and rotating to an internal position putting the device into a compact state. Additionally, the large rear wheel assemblies can be quickly removed to reduce the size and weight even further. Front and rear scissor over center locking mechanisms spread the device and lock it in the open position while a back rest locking mechanisms locks the back rest in an upright position along with locking it in the collapsed position. When locked in the collapsed position the wheelchair cannot be opened without releasing the backrest locking assembly release rings. 
         [0007]    With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. 
       OBJECTS OF THE INVENTION 
       [0008]    The principal advantage of the invention is to produce a wheelchair that will fold in two separate directions into a compact state and is easy to handle. 
         [0009]    Another advantage of the invention is to provide a compact bi-folding wheelchair that is sufficiently compact in design to enable its storage in standard luggage compartments in automobiles, airlines, trains and other means of transportation. 
         [0010]    Another advantage of the invention is to produce a wheelchair that folds in two different directions with the foot rests attached, so that when folded it is only slightly larger than the diameter of the large rear wheels, having the handle bar grips extending for easy manipulation. 
         [0011]    Another advantage of the invention is to produce a wheelchair with a front and back over center locking mechanism to hold the device in the open position. 
         [0012]    Another advantage of the invention is to produce a wheelchair with two additional spring-loaded locking mechanisms to lock the backrest up in the open position and lock it down in the closed position. 
         [0013]    Another advantage of the invention is to produce a wheelchair that in the extended or compact state is light enough for an elderly adult to handle. 
         [0014]    And still another advantage is to create a wheelchair with the large rear wheel assemblies that are easily removable by the means of pressing a plunger in the center of the axle to release the spring-loaded ball detent holding the wheel assembly to the frame. 
         [0015]    A further advantage of the invention is to produce a collapsible wheelchair that is substantial enough to comfortably support an average adult. 
         [0016]    A final advantage of this invention is to add a new and unique bi-folding wheelchair to the area of medical devices used to assist the handicapped. 
         [0017]    These together with other advantages of the invention, along with the various features of novelty, which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention. There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The accompanying drawings, which are incorporated in and form a part of this specification, illustrate certain embodiments of the invention and together with the description, serve to explain the principles of certain embodiments of this invention. 
           [0019]      FIG. 1  depicts a front perspective view of the bi-folding wheelchair, constructed in accordance with the present invention. 
           [0020]      FIG. 2  depicts a rear perspective view of the bi-folding wheelchair, constructed in accordance with the present invention. 
           [0021]      FIG. 3  depicts a side perspective view of a partially collapsed bi-folding wheelchair, constructed in accordance with the present invention. 
           [0022]      FIG. 4  depicts a side perspective view of a partially collapsed bi-folding wheelchair with one of the large rear wheels with the circular grip ring exploded away, constructed in accordance with the present invention. 
           [0023]      FIG. 5  depicts a side perspective view of the completely collapsed bi-folding wheelchair, constructed in accordance with the present invention. 
           [0024]      FIG. 6  depicts a side view of the spring-loaded locking mechanism located within the backrest support bars, constructed in accordance with the present invention. 
           [0025]      FIG. 7  depicts a side view of the bi-folding wheelchair frame in the upright position with the large rear wheel having the circular grip ring removed and the front caster wheels broken away displaying the sliding support mechanism and the breaking lever arm, constructed in accordance with the present invention. 
           [0026]      FIG. 8  depicts a side view of the bi-folding wheelchair in the folded position with the large rear wheel with the circular grip ring removed and the front caster wheels broken away. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]    Referring now to the drawings, wherein similar parts of the bi-folding wheelchair  10  are identified by like reference numerals, there is seen in  FIG. 1  a front perspective view of the bi-folding wheelchair  10  in the upright position, consisting of a right side frame member  12  and a left side frame member  14 . Attached to the front of the frame members  12  and  14  are conventional swivel casters  16  and  18 . Foot support extensions  20  and  22  holding foot supports  24  and  26  attached above swivel casters  16  and  18  have the ability to swivel separately from the casters to extend out for the support of the feet or swivel back out of the way when they are not needed or when the device is in the compact state. 
         [0028]    The right side frame member  12  and the left side frame member  14  are locked in the extended position by the front over center locking mechanism  28 . This is accomplished by the means of the right side locking arm  30  with the hand knob  32  going past the center line position to be held in place by the stop pin  34  on the left side locking arm  36 . The seat fabric  38  is stretched tightly when the front over center locking mechanism  28  is in the extended position. Additional support is achieved by the means of the back over center locking mechanism  40 . The backrest fabric  50  is stretched tightly when the back over center locking mechanism  40  is in the extended position. The right side locking arm  42  is attached to the right back rest support bar  52  by the means of the stanchion  54  and the left side locking arm  48  shown in  FIG. 2 , is attached to the left back rest support bar  56  by the means of the stanchion  58 . At the distal ends of the right and left backrest support bars  52  and  56  are the handgrips  60  and  62 . Attached to the sides of the backrest support bars  52  and  56  are the armrests  64  and  66 . The armrests  64  and  66  are pivotally attached to back rest support bars  52  and  56 . 
         [0029]      FIG. 2  depicting a rear perspective view of the bi-folding wheelchair  10  illustrates clearly the back over center locking mechanism  40  that operates in like manner to the front over center locking mechanism  28  where the right side locking arm  42  with the hand knob  44  goes past the center line position to be held in place by the stop pin  46  on the left side locking arm  48 . The wheel assemblies  92  and  94  uses conventional wheels  96  and spokes  98  equipped with handgrip rings  100 . The breaking disks  102  and  104  are attached to the inside of the wheel hubs  106  and  108 . The lower folding capability of the bi-folding wheelchair  10  is facilitated by the means of a compound scissor action with the right front pivot arm  148  and the right rear pivot arm  150  connecting to the right sliding wheel and break mounting unit  118  and the center folding member  152 . The left front pivot arm  154  and the left rear pivot arm  156  are connected to the left sliding wheel and break unit  120  and also attach to the center folding member  152 . Actuating arms  158  and  160  by being fixably attached to frame members  12  and  14  at pivot points  162 ,  164 , and on center folding member  152  at pivot points  166  and  168  exert pressure on the right and left sliding wheel and break unit  118  and  120  when the device is folded, moving the right and left wheel assemblies  92  and  94  forward to a more central location on the framework of the device. 
         [0030]      FIG. 3  depicts a side perspective view of the bi-folding wheelchair  10  in a partially collapsed position displaying the location of the right backrest locking assembly release ring  72  and the left backrest locking assembly release ring  74  of the back rest locking assembly  77 .  FIG. 4  depicts a similar view of the bi-folding wheelchair  10  in a partially collapsed position with the wheel assembly  92  exploded away from the right side frame member  12 . By removing the wheel hubcaps  112  and pushing in the spring loaded ball detent ends  114  the axles  110  will slide out of the orifices  116  in the right and left sliding wheel and break mounting units  118 . Hand break arms  124  and  126  actuate the breaking mechanism  122  that is attached to the break mounting unit  118  with a similar breaking mechanism  120  not visible on the opposite side. It must be noted that the wheel hubcaps  112  may be made of a rigid material to be removed prior to pushing the spring loaded ball detent end  114  for removing the wheel assembly  92 , or the wheel hubcaps  112  may be made from a flexible material. When the wheel hub caps  112  are made of a flexible material they will be left in place where pressure will deform them enough that the spring loaded ball detent end  114  will be actuated through them. 
         [0031]      FIG. 5  depicts a side perspective view of the completely collapsed bi-folding wheelchair  10 . This view illustrates the fact that the device is narrower than in the expanded condition and almost all the mechanisms fall within the diameter of the wheels  96 , with only a portion of the backrest locking mechanism  77  exposed. The hand grips  60  and  62  do extend and are used for rolling and manipulating the device when it is in the collapsed state. 
         [0032]      FIG. 6  shows right side view of the backrest locking assembly  77  with the left side being symmetrical. This view with areas broken away shows the mechanism located within the backrest support bar  52 . Release rings  72  and  74  are held in place by the means of the screws  76  attached to the spring loaded locking rods  78 . The springs  80  on the spring-loaded locking rods  78  maintains pressure on the spring-loaded locking rod tips  82  within the upright orifices  84  holding the backrest in the upright position. The upright locking orifices  84  and the collapsed locking orifices  86  are an integral part of the right and left locking plates  88  and  90  that are welded on the right and left frame members  12  and  14 . Directional arrow  70  indicates the direction that the backrest support bar  52  will rotate when the device is collapsed. A portion of the armrest  64  is shown attached to the backrest support bar  52 . 
         [0033]      FIG. 7  depicts a right side view of the bi-folding wheelchair  10  with the back rest support bar  52  in the upright position, and with the large rear wheel  96  and the circular handgrip ring  100  removed, and the swivel caster  16  broken away displaying the sliding support mechanism  118  and the breaking mechanism  122 . The breaking mechanisms  122  consist of the handbrake arms  124  and  126  that are attached to the break lever arms  128  and  130  and the break actuator arms  132  that are attached to the break mounting arms  134  operating the break shoes  136 . The armrests  64  and  66  are pivoted upwardly depicted by the rotational arrow  68  when the backrest support bars  52  and  56  are pivoted downwardly depicted by the rotational arrow  70  for storing the device 
         [0034]    The right and left sliding wheel and break mounting unit  118  facilitate the collapsibility of the device illustrated in the upright state in  FIG. 7  and in the collapsed state in  FIG. 8 . These figures show the right side only, with the right and left sides being symmetrical. The device collapses in the direction indicated by the direction arrows  68  and  78  by the means of the rear sliding member  138  and the front sliding member  140  of the sliding wheel and break mounting unit  118  sliding on the upper horizontal slide rod  142 . The lower portion of the sliding wheel and break mounting unit  118  is guided by the lower sliding member  144  that slides along the lower horizontal rail  146  of the frame member  12 . 
         [0035]      FIG. 8  depicts a side view of the bi-folding wheelchair  10  in the folded position with the large rear wheel  96  and the circular grip ring  100  removed, and the front caster wheels  16  and  18  broken away. Directional arrow  71  indicates the direction that the sliding wheel and break mounting unit  118  moves to achieve the collapsed state and where the wheel  96  is also centrally located on the frame member  12 . 
         [0036]    The bi-folding wheelchair  10  shown in the drawings and described in detail herein disclose arrangements of elements of particular construction and configuration for illustrating preferred embodiments of structure and method of operation of the present invention. It is to be understood, however, that elements of different con-struction and configuration and other arrangements thereof, other than those illustrated and described may be employed for providing a bi-folding wheelchair  10  in accordance with the spirit of this invention, and such changes, alternations and modifications as would occur to those skilled in the art are considered to be within the scope of this invention as broadly defined in the appended claims. 
         [0037]    Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.