Patent Publication Number: US-8973938-B2

Title: Universal foot tray for wheelchairs

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention pertains to the field of wheelchairs. More particularly, the invention pertains to a universal foot tray for wheelchairs. 
     2. Description of Related Art 
     As of 1993, there were 35 million people in nursing homes worldwide. In 2004, there were approximately 1.5 million people in nursing homes in the US. Many of these people have mobility issues, and require the use of a wheelchair. 
     Conventional wheelchairs include two foot pedals that can be flipped to the side when not in use. An example of a wheelchair  1  with prior art foot pedals  2  is shown in  FIG. 1 . The wheelchair  1  includes a seat  3 , a back  4  and side panels  13 . The wheelchair  1  also includes an armrest  5  and an arm  6 . It includes two wheels  7  with hand rims  8 , as well as smaller wheels or casters  9 . A cross brace  10  is the mechanism that collapses the chair  1  and a brake or wheel lock  12  permits the user to lock the wheelchair  1  in place. A push handle or hand grip  14  permits another person to push the wheelchair  1 . Front rigging  11  connects the foot plate  2  to the rest of the wheelchair  1 . The foot pedals  2  are also removable from the wheelchair  1 . 
     Pedals  2  for wheelchairs come in “left foot” pedals and “right foot” pedals, as well as elevating pedals (the pedals  2  in  FIG. 1  are examples of elevating pedals  2  with calf rests  16 ). While foot pedals  2  can be useful, they are not useful for everyone at all times, and often they are removed. Sometimes, something is needed to assist, or to keep the feet safe, during transport. Unfortunately, when the foot pedals  2  are flipped up, the user of the wheelchair  1  can not access the brake  12  or the hand rim  8  anymore. In designs where the pedals are flipped out when not in use, the rods stick out causing problems. 
     In addition, since the foot pedals  2  are removable, they can get misplaced, and are heavy to remove and reinstall. One reason to remove the foot pedals  2  is to allow the user to maintain leg strength and mobility. Each foot pedal  2  is approximately six pounds, and there are at least three different manufacturers of foot pedals. If pedals  2  are removed and left on the floor, they become a tripping hazard. In a nursing home, the pedals  2  are put in storage, creating a huge pile of assorted styles of pedals  2 . Different wheelchairs  1  have different spacings of pins. If foot pedals  2  are not used, some people fatigue from holding their feet up during transport. If their feet fall to the floor, there is a serious potential for harm. 
     Foot pedals  2  are also dangerous when they are in place. If someone is confused, and stands up with the standard foot pedals  2  on the wheelchair  1 , the person and the wheelchair  1  are thrown forward. The person is then on the floor, with the wheelchair  1  on top of them. With elevating foot pedals, if the pedals  2  are released and swung to the side of the wheelchair  1 , the lifting rods  15  can tear the skin of a bystander&#39;s leg. With the foot pedal  2  swung to the side, not only is the brake  12  inoperable, but the self propulsion wheel  8  on the wheelchair  1  is also blocked. 
     There is a need in the art for a universal foot tray that is easily installed on any design of wheelchair and can be stored on the wheelchair when not in use. 
     SUMMARY OF THE INVENTION 
     The universal tray apparatus includes a tray and mounting components. The mounting components preferably include at least one arm that connects to the tray, as well as at least one mounting portion that can be reversibly fastened to an existing portion of a wheelchair. One or more of the arms between the tray and the mounting portion is preferably made such that it can retract and extend, depending upon where the person using the tray apparatus prefers the tray to be in relation to the wheelchair. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a wheelchair with prior art foot pedals. 
         FIG. 2   a  shows a side perspective view of a wheelchair with a universal foot tray in an embodiment of the present invention. 
         FIG. 2   b  shows a side view of a wheelchair with the universal foot tray of  FIG. 2   a.    
         FIG. 2   c  shows a top down view of the wheelchair of  FIG. 2   a.    
         FIG. 3   a  shows a side perspective view of the tray in an embodiment of the present invention. 
         FIG. 3   b  shows another side perspective view of the tray of  FIG. 3   a.    
         FIG. 3   c  shows a bottom view of the tray of  FIG. 3   a  with wheels. 
         FIG. 3   d  shows the base and rod of the tray portion of the tray apparatus in embodiments with a base. 
         FIG. 4   a  shows the tray apparatus, including the tray and its mounting components. 
         FIG. 4   b  shows a side perspective view of the tray and its mounting components. 
         FIG. 4   c  shows the mounting components attached to a wheelchair. 
         FIG. 4   d  shows one part of the mounting clamp of the tray apparatus. 
         FIG. 4   e  shows a second part of the mounting clamp of the tray apparatus. 
         FIG. 4   f  shows the swinging tube frame of the tray apparatus of  FIG. 4   a.    
         FIG. 4   g  shows a close up view of one of the mounting clamps and a knob of the mounting portion of the tray apparatus. 
         FIG. 5   a  shows a top down view of a wheelchair with the tray in an extended position. 
         FIG. 5   b  shows a top down view of the wheelchair of  FIG. 4   a  in a less extended position. 
         FIG. 5   c  shows the space taken by casters as they turn. 
         FIG. 5   d  shows another view of the space taken by the casters as they turn. 
         FIG. 6   a  shows a side perspective view of the tray in a storage position with the wheelchair open. 
         FIG. 6   b  shows a side view of the tray in a storage position with the wheelchair open. 
         FIG. 6   c  shows another side perspective view of the tray stored with the wheelchair open. 
         FIG. 6   d  shows a back view of the tray stored with the wheelchair open. 
         FIG. 7  shows a portion of the wheelchair with the tray portion removed and the wheelchair folded. 
         FIG. 8   a  shows an alternative embodiment of a universal tray apparatus with a swinging tube frame attached to a wheelchair. 
         FIG. 8   b  shows a top down view of the wheelchair of  FIG. 8   a.    
         FIG. 9   a  shows a top down view of the universal tray apparatus of  FIGS. 8   a  and  8   b.    
         FIG. 9   b  shows a view from the bottom of the universal tray apparatus of  FIG. 9   a.    
         FIG. 9   c  shows a side perspective view of the universal tray apparatus of  FIG. 9   a.    
         FIG. 9   d  shows a view of the swinging tube frame of the universal tray apparatus of  FIG. 9   a.    
         FIG. 9   e  shows a cross-sectional view along lines E-E of  FIG. 9   g.    
         FIG. 9   f  shows a cross-sectional view along lines F-F of  FIG. 9   g.    
         FIG. 9   g  shows some preferred dimensions for the swinging tube frame of  FIG. 9   a.    
         FIG. 10   a  shows a side perspective view of a tray apparatus in an alternative embodiment of the present invention. 
         FIG. 10   b  shows a top down view of the tray apparatus of  FIG. 10   a.    
         FIG. 10   c  shows a side perspective view of the tray apparatus of  FIG. 10   a , without the tray. 
         FIG. 10   d  shows another view of the tray apparatus of  FIG. 10   a , without the tray. 
         FIG. 10   e  shows a top down view of the tray apparatus of  FIG. 10   a , without the tray. 
         FIG. 10   f  shows another view of the tray apparatus of  FIG. 10   a , without the tray. 
         FIG. 11   a  shows a side perspective view of a first example of a mounting block for the tray apparatus in an embodiment of the present invention. 
         FIG. 11   b  shows a top down view of the first example of a mounting block shown in  FIG. 11   a.    
         FIG. 11   c  shows a notch side view of the first example of a mounting block shown in  FIG. 11   a.    
         FIG. 11   d  shows a side perspective view of a second example of a mounting block for the tray apparatus in an embodiment of the present invention. 
         FIG. 11   e  shows a top down view of the second example of a mounting block shown in  FIG. 11   d.    
         FIG. 11   f  shows a notch side view of the second example of a mounting block shown in  FIG. 11   d.    
         FIG. 11   g  shows a side view of the mounting block, showing the horizontal notch. 
         FIG. 11   h  shows a top down view of the mounting block, showing the vertical notch. 
         FIG. 12   a  shows a top front view of the universal tray apparatus on the front of a wheelchair. 
         FIG. 12   b  shows a close up view of the mounting block and clamp plates of the tray apparatus on a wheelchair. 
         FIG. 12   c  shows a view of the tray of the tray apparatus of  FIG. 12   a  folded under the wheelchair. 
         FIG. 12   d  shows a top down view of a wheelchair with the tray apparatus. 
         FIG. 12   e  shows a side perspective view of a wheelchair with the tray apparatus. 
         FIG. 13   a  shows a cross-sectional view of the two arms of the tray apparatus that connect to the tray. 
         FIG. 13   b  shows a side perspective view of the two arms of  FIG. 13   a.    
         FIG. 14   a  shows a cross-sectional view of the other arms of the tray apparatus. 
         FIG. 14   b  shows a side perspective view of the arms of  FIG. 14   a.    
         FIG. 15   a  shows an example of a clamp plate that fastens to the mounting block in an embodiment of the invention. 
         FIG. 15   b  shows a side view of the clamp plate of  FIG. 15   a.    
         FIG. 15   c  shows the clamp plate of  FIG. 15   a  with some preferred dimensions. 
     
    
    
     The drawings are not drawn to scale. 
     DETAILED DESCRIPTION OF THE INVENTION 
     A universal tray apparatus includes a tray for a wheelchair user to place his feet on either when the wheelchair is stationary or moving. The universal tray apparatus can be extended or retracted to a comfortable location for the person in the wheelchair. The mount portion of the universal tray apparatus is mounted on a portion of the wheelchair so that the universal tray apparatus can extend in and out depending on a person&#39;s height. The universal tray apparatus is also designed to fold under the wheelchair when not in use. The universal tray apparatus is easily removable from the wheelchair and preferably lightweight. The universal tray apparatus can preferably be quickly attached or detached from the wheelchair. The tray apparatus can be mounted on the bottom frame found on all wheelchairs. In embodiments with a swing arm, the tray can be adjusted to a person&#39;s height. 
     The entire universal tray device can be easily stored under the wheelchair while it is in the open position. If the user wants to fold the wheelchair, it is simple to remove the tray only, which is lightweight and easy to store elsewhere, while the mounting bracket/system remains on the chair. 
     The foot trays described herein are preferably lightweight, universal by fitting both feet on one tray, easy to take on and off the wheelchair, adjustable for different leg lengths, adjustable for different makes of chairs, and are easily cleaned. 
     In addition, the mounting bracket of the tray folds up with the chair when the chair is folded. The tray is easily stored in the empty space under the wheelchair seat. 
     All of these advantages allow for independent mobility, as well as foot safety when a person becomes fatigued. 
     The universal tray apparatus includes a tray and mounting components. The mounting components preferably include at least one arm that connects to the tray, as well as at least one mounting portion that can be reversibly fastened to an existing portion of a wheelchair. One or more of the arms between the tray and the mounting portion is preferably made such that it can retract and extend, depending upon where the person using the tray apparatus prefers the tray to be in relation to the wheelchair. 
     In preferred embodiments, some or all of the mounting components are made of aluminum. 
     In one preferred embodiment, the tray is 9 inches×14 inches. The number of inches between the casters on wheelchairs is generally constant (11.5 inches between the casters). The distance between the back wheels of chairs and the distance between the front and back wheels of chairs varies. The transport trays described herein include adjustable mounting to accommodate for these variables. In another preferred embodiment, the tray is made of plastic. The top of the tray is preferably made of plastic, and the bottom has casters to effectively turn corners. In one preferred embodiment, the plastic tray is poured or injection molded. 
     In other preferred embodiments, the tray is made of other materials, including aluminum or other metals. Preferably, the foot tray supports at least 70 pounds. In one preferred embodiment, the tray portion of the universal tray device is supported by the floor and wheels. 
     In one preferred embodiment, the tray is on two wheels. In one preferred embodiment, the two wheels are 3 inch wheels. In other embodiments, other numbers (for example, one, three, or more than three wheels) and sizes of wheels could be used to make the tray easily transportable along the floor as the wheelchair moves. The number and size of wheels need to provide sufficient stability so if someone stands up, the tray does not pitch forward, dumping the user out of the chair. The number and size of the wheels are also chosen to maximize the freedom of motion that the user experiences while using the tray in combination with the wheelchair. In one preferred embodiment, a double or multiple wheel where each individual wheel works independently, could be used. These wheels permit maximum maneuverability. One example of single, double, and triple wheel with great maneuverability are the Rotacaster® multi-directional wheels (Rotacaster Wheel Limited, Newcastle, Australia). 
     In some preferred embodiments, there is a steel plate or base on the underside of the tray, which supports the tray and the weight of the user. In other embodiments, no plate is necessary. The plastic trays are preferably designed to be able to hold up to 190 pounds (a 190 pound person standing straight on the tray) without breaking. The tray will flex, but it will not break. The shape of the tray may vary, as long as the tray can comfortably hold both feet of a variety of sizes of people. The tray may have pointed edges, for example edges cut at a right angle, but can alternatively have softer edges on any portion of the tray. In some embodiments, there are softer edges on the back lip of the tray than the front of the tray. 
     The universal tray embodiments described herein can preferably be used on any standard wheelchair. In other preferred embodiments, the universal tray apparatus can be designed for use on bariatric wheelchairs. In these embodiments, the tray may be wider, and would need more than two wheels in order to support the user of the bariatric wheelchair. The tray apparatus in this embodiment may also preferably include a steel or other metal support on the underside of the tray. 
     One preferred embodiment for a universal tray apparatus is shown in  FIGS. 2 through 7 . Most of the components of the universal tray apparatus  110  can be seen in  FIGS. 4   a  and  4   b . More specifically, a tray  120 , preferably having wheels or casters  114 , is connected to an inner tube or rod  115  with bushings  123 . The inner tube  115  is also connected to a swinging tube frame  116 . The swinging tube frame  116  is attached to two mounting blocks  118 . Knobs or fasteners  122 , an end plug  124  and a locking knob  125  (shown in  FIG. 4   c ) are also included. 
       FIGS. 2   a  through  2   c  show a wheelchair  100  with the tray apparatus  110  attached to the bottom frame  131  of the wheelchair  100 . The wheelchair  100  has many of the same components as discussed with respect to the wheelchair  1  and the same reference numerals are being used herein for those components of the wheelchair  100  not otherwise described. However, the foot pedals  2  and front rigging  11  are replaced with the tray apparatus  110 . 
     The tray apparatus  110  and its individual components are shown in  FIGS. 3   a  through  3   c  and  4   a  through  4   g .  FIGS. 3   a  and  3   b  show perspective top and bottom views of the tray  120 , respectively. Note that, while the tray  120  has a particular six sided shape in these figures, the tray  120  may be of any shape that permits the comfortable placement of a wheelchair user&#39;s feet on the tray without impeding the movement of the wheelchair  100 . Some tray  120  shapes include square, rectangular, oval, or round trays  120 . While a lip  102  is preferred, it is not required. 
     In one preferred embodiment, the tray is preferably approximately 14 inches long and 9.5 inches wide. In another preferred embodiment, the tray is preferably approximately 12.5 inches long and 9.5 inches wide. Some preferred dimensions for the particular shaped tray  120  in  FIGS. 3   a  through  3   c  also include the angled portions  101  of the tray  120  on either side being preferably each approximately 2.5 inches wide and cut at an approximately 30 degree angle. The tray is preferably 1.3 inches high in its narrow portion  103  and 2.2 inches high on its elevated edge or lip  102 , which are approximately 4.75 long (from its highest to where it meets the narrow portion  103 ). 
     As shown in  FIG. 3   c  and  FIG. 3   d , on the underside of the tray  120 , there is preferably a base  112  and a rod or tube  113 . In some preferred embodiments, the base  112  and/or the rod  113  are made of steel, aluminum, or another sturdy metal, to add strength to the tray  120 . While the base  112  is shown in the figures, in other preferred embodiments, the base  112  is not required as part of the tray  120 . Since the tray  120  is made of sturdy plastic, it does not require a base  112  for strength. The rod  113  is permanently affixed directly to the bottom of the tray  120  in embodiments without a base  112 . Wheels, or casters,  114  are preferably attached to the base  112 . In embodiments without a base  112 , the wheels  114  are permanently fastened or otherwise attached directly to the underside of the tray  120 . While two wheels  114  are shown in the figures, any number of wheels  114  that permit smooth movement of the tray  120  across the floor could be used. The wheels or casters  114  preferably swivel and turn 360°. 
     In one preferred embodiment, the rod  113  preferably fits within a hole  111  centered lengthwise on the tray  120 . In one preferred embodiment, the rod has a 0.777 inch diameter and the hole  111  in the tray  120  has a 0.875 inch diameter. In embodiments with a base  112 , the rod  113  also fits through holes  111  in the base  112 . 
     As shown in  FIGS. 4   a  through  4   g , the tray apparatus  110  also includes mounting components that permit a reversible connection between the tray  120  of the tray apparatus  110  and a wheelchair  100 . An inner tube  115  is received by the rod  113  to connect the tray  120  the rest of the mounting portion of the apparatus  110 . The inner tube  115  fits into the rod  113  and also into a swinging tube frame  116 . In alternative embodiments, the inner tube  115  could have a wider diameter than either the rod  113  or the swinging tube frame  116 , such that the swinging tube frame  116  and/or the rod  113  fit inside the ends of the inner tube  115 . In one preferred embodiment, the inner tube has a 0.652 inch inner diameter and a 0.750 inch outer diameter. However, the inner tube  115  can be any diameter that permits it to fit into the rod  113  of the tray  120  and the swinging tube frame  116 . In one preferred embodiment, the inner tube is approximately 23.25 inches long. 
     Tube bushings or connectors  123  connect the rod  113  of the tray  120  to the inner tube  115 , as well as connecting the inner tube  115  to the swinging tube frame  116 . The swinging tube frame permits movement of the tray apparatus  110 . The inner tube  115  and the rod  113  also permit the tray apparatus  110  to extend and retract, as shown in  FIGS. 5   a  and  5   b . The inner tube  115  slides in and out of the rod  113  for adjustability. In some preferred embodiments, a spring plunger or button can be used in combinations with holes to change the length of the inner tube  115 . The tube diameter of the swinging tube frame  116  is preferably large enough to accommodate the inner tube  115 . In one preferred embodiment, where the inner tube has an approximately ⅞ inch diameter, the swinging tube frame has an approximately one inch diameter. 
     The swinging tube frame  116  preferably includes two sets of parallel arms  140 ,  141 ,  142 . The longer  141  of the two parallel arms  141 ,  142  connects to the inner tube  115 . The other two arms or braces  140  are the same length as each other and perpendicularly extend from the end of long arm  141  opposite the end that attaches to the inner tube  115 . The second arm  142  runs perpendicular to the arms  140  on the end of the arms  140  opposite the long arm  141 . The four arms  140 ,  141 ,  142  of the swinging tube frame  116  make a flag or P shape. 
     The short arm  142  of the swinging tube frame  116  fits into two mounting clamps  118 , each mounting clamp  118  formed by two parts  117  and  119 , shown in  FIGS. 4   d  and  4   e . Each of the larger mounting clamp parts  119  includes a hole  130  through which the swinging tube frame  116  is placed. The swinging tube frame is preferably permanently connected to the larger mounting clamp part  119  through the hole  130 . The mounting clamp part  119  also includes a channel  133  that mates with a corresponding channel  132  in the mounting clamp part  117  to hold the mounting clamp  118  and the tray apparatus  110  in place on the wheelchair bar  131 . An end plug  124  is preferably located at the end of the swinging tube frame  116 , to hold the mounting clamps  118  on the swinging tube frame  116 . While two mounting clamps  118  are shown in the figures, one mounting clamp  118  or more than two mounting clamps  118  could alternatively be used to contact the tray apparatus  110  to the wheelchair bar  131 . 
     Some preferred dimensions for the mounting clamp parts  117  and  119  include a total height of approximately 1.500 inches for part  119  at its highest point. The height of part  119  at its lower portion is preferably approximately 0.600 inches. The diameter of the hole for the swinging tube frame  116  is preferably approximately 0.770 inches. The total height of part  117 , including the lip  138 , is preferably approximately 0.600. The height of the portion without the lip  138  is preferably approximately 0.540 inches. In embodiments with a lip  138 , the lip  138  helps lock the part  117  to the part  119 , to effectively attach the parts  117  and  119  to the wheelchair  100 . The lip  138  aligns the two halves  117  and  119  of the mounting clamp  118  to one another and allows the mounting clamp  118  to go completely around the rod of the wheelchair  100 . In one preferred embodiment, the width of parts  117  and  119  are preferably approximately 1.00 inch. Parts  117  and  119  are also preferably approximately 1.5 inches high and 3 inches long in one preferred embodiment. 
     Although the mounting clamps  118  and their parts  117  and  119  are shown as specific shapes in the figures, any shape that permits the mounting clamps  118  to hold the swinging tube frame  116  and to reversibly fasten to a bar  131  of a wheelchair  100  could be used. 
     At least one knob  122  fastens the two parts  117  and  119  of the mounting clamps  118  to a back rod  131  of the wheelchair  100 . The knob  122  fits through the mating holes  135  of the two clamping parts  117  and  119 . In one preferred embodiment, the knob  122  is a four prong plastic knob  122 . A second knob  125 , shown in  FIG. 4   g , locks the tray apparatus  110  in place when it is in storage mode when placed through the hole  136  in mounting clamp part  119 . The knob  125  needs to be lifted (pulled) to release the tray apparatus  110  and convert it from storage mode to being able to let the tray  120  ride on the floor. 
       FIGS. 5   a  and  5   b  show a top down view of the tray  120  attached to the wheelchair  100  in an extended  400  and retracted  410  position, respectively. Expansion and retraction of the tray  120  is preferably accomplished by lengthening and shortening the inner tube  115 , which moves within the rod  113  and or swinging tube frame  116 . The adjustment is made in one embodiment by loosening the bushings  123  to expand or retract the inner tube  115 , then tightening the bushings  123  again when the inner tube  115  is at the desired length. In another embodiment, a spring plunger or button on the inner tube  115 , and a number of holes on the rod  113  or the swinging tube frame  116 , into which the spring plunger fits, are used, so that the inner tube  115  can be adjusted by choosing a hole in the swing tube frame or rod  113  in which the spring plunger is fit to get the desired length of the inner tube  115 . 
       FIGS. 5   c  and  5   d  show the space  160  the casters  150  need to turn. A caster (or castor) is an undriven, single, double, or compound wheel that is designed to be mounted to the bottom of a larger object (the “vehicle”) so as to enable that object to be easily moved. They are available in various sizes, and are commonly made of rubber, plastic, nylon, aluminum, or stainless steel. Casters may be fixed to roll along a straight line path, or mounted on a pivot such that the wheel will automatically align itself to the direction of travel. 
     The casters  150  need a lot of space  160  to turn and they will not have full motion if the tray  120  is in close to the wheelchair  100 . In one preferred embodiment, the tray  120  has a slight taper so there is less chance of interfering with the casters  150 . Retraction of the tray  120  may be limited with small wheelchairs  100  because the tray  120  needs to clear the casters  150  of the wheelchair  100 . For taller people using the wheelchair  100 , the inner tube  115  can be made longer, especially in smaller model wheelchairs  100 . In embodiments with a spring plunger, the spring plunger is pulled up and put in a hole that increases the extension of the inner tube  115  and the tray  120 . As shown in  FIGS. 6   c  and  6   d , when stored, the tray  120  is stored above the casters  160  so that it does not interfere with the movement of the casters. 
       FIGS. 6   a  through  6   d  show the tray stored when the wheelchair is in the open position.  FIGS. 6   c  and  6   d  show the tray stored above the casters so they can swing, but the support rod is below the X brace  170  on the back of the wheelchair. The room between the X brace and the front of the chair is what makes the tray preferably just 9 inches front to back. 
       FIG. 7  shows the folded mode, where the tray portion of the universal tray  120  has been removed, and the tray support arm  115  and swing arm  116  have been rotated vertically, as shown in the Figure. 
     An alternative shape for the swinging tube frame  216  for the universal tray apparatus  110  is shown in  FIGS. 8   a  through  9   d . The universal tray apparatus attaches to the wheelchair in a similar manner as discussed with respect to  FIGS. 2 through 7 , but the shape of the swinging tube frame  216  is different than the swinging tube frame  116  shown in the previous embodiment. More specifically, instead of a swinging tube frame shape  116  having two parallel braces  140  perpendicular to two parallel rods or tubes  141 ,  142 , the swinging tube frame  216  is J-shaped, with the long side  241  of the J connecting to the inner tube  115  and the shorter side  242  of the J including the mounting clamps  118 . In one preferred embodiment, the swinging tube frame  216  the dimensions shown in  FIGS. 9   e  through  9   g.    
     In preferred embodiments, the inner tube  115 , swinging tube frame  116 ,  216 , and the mounting blocks  117 ,  118 ,  119  are preferably made of sturdy aluminum, steel, another preferably lightweight metal, or a sturdy plastic material. 
     The tray  120  must extend past the front wheels of the wheelchair  100  so that the wheelchair  100  can make turns. The swinging tube frame  216  mounts to the wheelchair, while the inner tube  115  makes the adjustments for the person in the wheelchair  100  to that person&#39;s leg length. In one preferred embodiment, there is a knob or spring plunger as part of the inner tube  115  that can be lifted up so that it can be moved to alternative holes in the swinging tube frame  116 ,  216 , or the rod  113  to adjust the length of the inner tube  115  and subsequently how far the tray  120  extends from the wheel chair  100 . The embodiments shown in  FIGS. 2-9  are preferred on older Everest and Jennings wheelchairs. 
     An alternative embodiment for the universal tray device is shown in  FIGS. 10 through 15 . In this embodiment, the universal tray apparatus  310  is reversibly connected to a wheelchair  300  using four arms  315 ,  316 ,  317 , preferably made of aluminum, and a block  330  that attaches to the back of the wheelchair using one or more clamp plates  334 . 
     Most of the components of the universal tray apparatus  310  can be seen in  FIGS. 10   a  and  10   b . More specifically, a tray  320 , preferably having wheels or casters  314 , is connected to two arms  315 , which preferably include hinges  318  and a vertical portion  319 . A second arm  316  connects to the vertical portion  319  of the arm  315 . A third arm  317  connects to a mounting block  340 ,  350 , with two notches  332  and  333  (shown in  FIGS. 11   a  through  11   f ). Two clamp plates  334 , fasteners  338 , and magnets  323  are also preferably included. 
     The frame of the universal tray apparatus in this embodiment is preferably made of aluminum. 
     Every wheelchair  300  includes two bars: one horizontal bar  337  and one vertical bar  336 , on the back of the wheelchair  300 . The diameter of these bars  336  and  337  differ depending on the make and manufacture of the particular wheelchairs  300 . In many wheelchairs, these bars  336  and  337  have a one inch angle from front to back. 
     In this embodiment, a mounting block  330  attaches to the back of the wheelchair  300 . The mounting block  330  preferably has two notches  331  and  332 . These two notches  331  fit the vertical bar  336  and the horizontal bar  337  of the wheelchair  300 , respectively. The notches  331  and  332  are each able accommodate a lot of different diameters of wheelchair bars  336  and  337 . 
     At least one clamp plate  334  is preferably used to reversibly attach the universal tray apparatus  310  to the wheelchair  300 . The clamp plate  334  is attached to the mounting block  330  using at least one fastener. In one embodiment, there is a first clamp plate  334  that is placed horizontally on an opposite side of the horizontal bar  337  from the mounting block  330 , to sandwich and hold the horizontal bar  337  in place between the mounting block  330  and the clamp plate  334 . A second clamp plate  334  is placed vertically on an opposite side of the vertical bar  336  from the mounting block  330 , to sandwich and hold the vertical bar  336  in place between the mounting block  330  and the clamp plate  334 . 
     Some preferred dimensions for the device are found in  FIGS. 10   e  and  10   f.    
     Two examples  340 ,  350  of a mounting block  330  are shown in  FIGS. 11   a  through  11   f . The mounting block  350  fits most wheelchairs. However, the mounting block  340  is more universal, because it can also fit on certain wheelchairs that can raise the axle on the wheelchair (for example, the Invacare® Tracer® wheelchair). Since the mounting block  340  is longer, the extended block  340  can go up when the axle of the wheelchair goes up. 
     The mounting blocks  330  are preferably made of aluminum. Both of the mounting blocks  340  and  350  are also shown as alternatives in  FIGS. 10   c - 10   f , but only one mounting block is preferably a part of each tray apparatus  310 . The mounting block  340  is rectangular and is larger than the mounting block  350 , which is preferably square. In a preferred embodiment, the mounting block  350  is a three inch square aluminum block  350 . The mounting blocks  340 ,  350  each include a vertical notch  331  and a horizontal notch  332  for holding the vertical bar  336  and the horizontal  337  of the wheelchair  300 , respectively. Each of these blocks  340 ,  350  also each preferably include two pairs of holes  333  for fastening two clamp plates  334  to the mounting blocks  340 ,  350  and sandwiching the vertical  336  and horizontal  337  bars between the mounting block  340 ,  350  and the clamp plates  334 .  FIGS. 11   c  and  11   f  show some preferred dimensions for the two different mounting block  340 ,  350  embodiments. 
       FIGS. 11   g  and  11   h  show some preferred dimensions of the horizontal notch  332  and the vertical notch  331 , respectively for the mounting blocks,  330 ,  340 ,  350 . The angle in  FIG. 11   h  is also preferably 90 degrees. A 90 degree angle is important as the diameter of the bottom rail varies a little from wheelchair to wheelchair. A 90 degree notch allows for the difference so the mounting block can be universal. 
     An arm  317 , preferably made of aluminum, attaches to the mounting block  330 , preferably using one or more fasteners  339 . The arm  317  also attaches to a second arm  316 , placed perpendicular to the first arm  317 . The second arm  316  attaches to two additional arms  315 , with vertical portions  319  of each of the additional arms  315  spaced evenly from each other and located at approximately a center of the second arm  316 . The two arms  315  also each include a horizontal portion  322  that connects to the vertical portion  319  via a hinge  318 , and is preferably fastened to a tray  320  by at least one fastener  321  on an end of the horizontal portion  322  opposite the hinges  318 . The fasteners  321  preferably permit the tray  320  to be easily unfastened from the arms  315  such that the tray apparatus  310  without the tray can be easily stored under the wheelchair  300  with or without the tray  320 . There are also preferably at least one additional set of hinges  318  on the horizontal portion  322  of the two arms  315 , which allow the tray  320  to fold under the wheelchair  300  when not in use, as shown in  FIG. 12   c . The hinges  318  preferably include nylon bushings, which permit the tray apparatus to ride smoothly over various floor types. For example, the tray apparatus  310  is able to go over carpets smoothly. 
     In one preferred embodiment, the tray  320  has a slight taper so there is less chance of interfering with the casters  150 . Retraction of the tray  320  may be limited with small wheelchairs  300  because the tray  320  needs to clear the casters  150  of the wheelchair  300 . For taller people using the wheelchair  300 , the two arms  315  can be made longer, especially in smaller model wheelchairs  300 . 
     Similar to the tray  120  in earlier embodiments, the tray  320  preferably includes at least two casters or wheels  314 . While the tray  320  is shown as six-sided in the figures, the tray could be of any size and shape that would effectively hold a person&#39;s feet while in the wheelchair  300 . 
     In one preferred embodiment, the tray in its folded position is held secure by one or more magnets  323 , which are shown in  FIGS. 10   a  and  10   b . In one preferred embodiment, the magnets  323  are preferably approximately nickel size. In other preferred embodiments, the magnets are preferably neodymium rare earth magnets. In one preferred embodiment, the magnets are disc-shaped or ring magnets. In one preferred embodiments, the magnets are 1″×¼″ countersunk ring magnets, preferably with a plastic coating, from K&amp;J Magnetics (K&amp; J Magnetics, Inc., Jamison, Pa.). 
       FIGS. 13   a  and  13   b  show a preferred design for the arms  315 . The design has a cross-section with an interior shape  341  shown in  FIG. 13   a . The cross-section shows a groove through the middle of the arms. An alien wrench can be used to adjust the distance that these arms  315  extend during use, thereby allowing the tray  320  to retract or extend as needed. These arms are preferably made of aluminum, although other sturdy materials, such as plastic or steel could be used. Other designs that have the strength to withstand weight are also possible. 
       FIGS. 14   a  and  14   b  show a preferred design for the arms  316 ,  317 . Either or both of the arms  316 ,  317  preferably have this design for the beam or arm  316 ,  317 . The design has a cross-section with an interior shape  342  shown in  FIG. 14   a . These arms are preferably made of aluminum, although other sturdy materials, such as plastic or steel could be used. Other designs that have the strength to withstand weight are also possible. 
     In one preferred embodiment, the arms  315 ,  316 ,  317  are made of MiniTec T-slotted aluminum profiles (MiniTec Framing Systems, LLC, Victor, N.Y.), like the cross-sections shown in  FIGS. 13   a  and  14   a . This permits the arms to connect to each other without the need for fasteners and also permits easy adjustment of the arms. In embodiments using MiniTec arms, the arms have set screws that are fit to an alien wrench. The screws allow for adjustments to raise or lowering any of the arms  315 ,  316 ,  317 . The arms  315 ,  316 ,  317  are connected by their hinges. The set screws are out of reach in the channels of the arms  315 ,  316 ,  317  so they can not be tampered with by accident. In other preferred embodiments, the hinges  318  are preferably made by MiniTec (MiniTec Framing Systems, LLC, Victor, N.Y.). 
     However, other types and materials of bars, rods, or tubes, for example steel, aluminum, or sturdy plastic, could be used for the arms  115 ,  116 ,  315 ,  316 ,  317  in any of the embodiments described herein. 
       FIGS. 15   a  through  15   c  show a clamp plate  334 . Some preferred dimensions for the clamp plate  334  are shown in  FIG. 15   c . In one preferred embodiment, the width of the clamp plate (shown in  FIG. 15   b ) is preferably 0.25 inches. Although the shape is shown as an octagon in the figure, the clamp plate can be of any shape that effectively clamps the wheelchair bars between the clamp plate and the mounting block. For example, the clamp plate could be oval or rectangular. In preferred embodiments, two clamp plates are used. Each clamp plate  334  preferably has two holes, so that four fasteners  339 , or screws, go through the block  330  to hold the wheelchair bars  331  and  332  in place between the block  330  and the clamp plates  334 . In preferred embodiments, each clamp plate is a one inch aluminum plate. 
     The fasteners  339  that attach the arm  317  to the mounting block  330  are preferably the same type of fasteners  339  that are used to clamp the clamp plate  334  to the block  330 . 
     Similar to the first embodiment, the tray device in this embodiment folds up into dead space under wheelchair. This is accomplished using the hinges  318  on the arms  315 . 
     In one preferred embodiment, the universal tray device includes a remote control that controls the tray. The remote control allows the tray to be extended, adjusting the extension, or put into a storage position under the wheelchair. In one preferred embodiment, the remote control unfolds the tray  120 ,  320  from the stored position under the seat  3  and extend the length of the tray  120 ,  320  to the correct length for the person using the wheelchair  100 ,  300 . 
     In one alternative embodiment, instead of a tray, foot sliders can be put on the user&#39;s feet, to slide them along the floor. These sliders may be similar to furniture sliders attached to easily slip on and slip off shoes, such as flip flops. 
     In one preferred embodiment, the tray is in a storage bag on the side of the wheelchair, to take it on or off. 
     Accordingly, it is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.