Abstract:
A robust multi-wall tray which is easily retrofitable to a wheelchair. Due to the structural design, the tray is lightweight but yet more rigid than conventional solid wheelchair trays. The multi-wall tray can be secured to a wheelchair with conventional means or with several novel means that provide a smooth work surface free of screws or Velcro™. A novel prior art adjustable tray support structure can also be integrated into the multi-wall tray to allow the system to mount robustly to the frame of a wheelchair and also allow the tray to fold away to the side of the wheelchair when not in use. Additionally, the multi-wall tray can have a sealed perimeter to create an enclosure for protecting electronic devices. The design can support electronic devices for computer assisted living while also providing a tray work surface for reading, writing or eating.

Description:
RELATED APPLICATION  
     Priority Claim  
       [0001]     This application is a continuation-in-part of U.S. patent application Ser. No. 11/200,838, filed Aug. 10, 2005, which claims the benefit of U.S. provisional application Ser. No. 60/600,853, filed Aug. 12, 2004, both of which are hereby incorporated herein by reference in their entirety. This application also claims the benefit of U.S. provisional application Ser. No. 60/680,153, filed May 12, 2005, which is also hereby incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The invention relates generally to multi-wall trays. More specifically, the invention relates to a plastic wheelchair tray which is engineered to be lightweight, yet very strong, and can house various mechanical and electronic components.  
         [0004]     2. Description of Prior Art  
         [0005]     It can be appreciated that wheelchair trays have been in use for years. Wheelchair trays serve a multifunction role as an eating surface, work surface or general platform to perform everyday tasks. Typically, a wheelchair tray is comprised of a platform which is secured onto the top of the wheelchair armrests and contours around the torso of the wheelchair user. The prior art wheelchair tray is typically made of solid wood or plastic and is normally between ¼″ and ⅜″ thick. Wheelchair trays typically mount to the wheelchair with hook and loop (i.e. Velcro®) straps that wrap around the top of the tray (or through holes in the tray) and underneath the armrests of the wheelchair; alternate mounting means may include clamps or tubes that are permanently mounted to the underside of the tray and, when installed to the wheelchair, secure the tray to the wheelchair armrests.  
         [0006]     However, when the conventional solid wheelchair tray is secured to a wheelchair and an item such as a portable laptop computer is placed on top of this type of wheelchair tray, the tray flexes downward at the non-secured, cantilevered end. This flexing usage scenario can be improved slightly by manufacturing the tray from a thicker solid material. However, utilizing the same but only thicker material for the wheelchair tray also means that the tray will increase in weight. Existing ¼″ thick wheelchair trays made of acrylic or polycarbonate plastic which are sized for adults typically weigh between 4 lbs and 6 lbs. Utilizing the same plastic material which is only ⅛″ thicker can typically add another 1 lb to the weight of the tray. Any added weight due to the use of a thicker material will make it more difficult for the wheelchair user to hold onto the wheelchair tray during installation and removal to/from the wheelchair.  
         [0007]     Wheelchair trays manufactured from wood can be more rigid than plastic trays. However, one problem with conventional wooden wheelchair trays is that they do not provide transparency and thus prevent the user from seeing his/her feet during use. The provision of transparency in a wheelchair tray can relate directly to the ability of a wheelchair user to navigate the wheelchair and can also present psychological benefits to the user. The wooden trays which are more rigid than plastic are heavy and can, therefore, present another problem to the wheelchair bound individual. The weight of the wheelchair tray directly impacts the ability of the user or caregiver to remove and place the tray onto the wheelchair. Depending upon the thickness of current wooden and clear plastic wheelchair trays, the weight of the tray often ranges from 4 lbs. to 8 lbs and, consequently, a large portion of handicapped users need assistance from a caregiver to remove and install the tray onto the wheelchair.  
         [0008]     Conventional solid wheelchair trays have a limited amount of space available on the top surface of the tray for daily use. This limited amount of “real estate” often causes objects to fall from the surface, necessitating the need for a raised rim to contain objects. Current wheelchair trays typically use a raised rim to prevent objects from rolling from the top surface of the trays. However, this is not the only function that the rim may serve. A solid rim is often attached to the wheelchair tray to provide additional rigidity to the tray, due to flexing that occurs with standard solid trays when an object with any considerable weight is applied to the tray. This solid rim may be manufactured from aluminum or a high-durometer plastic. A rigid rim made of aluminum may pose a safety risk for individuals dining everyday use, due to the proximity of the arms on top of the tray. Current designs can injure someone through bumping, sliding or scraping of the arms against this rim. Due to poor circulation that may be present in many wheelchair users, skin breakdown and infection can occur from the slightest skin abrasion. In addition, some wheelchair users may have tremor disorders or trashing of the body due to a disability such as epilepsy—the use of a solid protruding rim may pose a high risk of injury and in many cases can prevent the use of this type of wheelchair tray altogether.  
         [0009]     Recent technologies have allowed electronics to be manufactured in a unitary construction, whereby the computer&#39;s microprocessor, visual display and associated hardware are combined into one compact unit. The iPod®, personal data assistant (PDA), notebook computer and tablet PC are examples of products utilizing this space-saving technology. It can be appreciated that such electronic devices have been in use for years. One would think that these compact electronics could be easily used by wheelchair users. However, these devices have unique mounting and liquid-protection requirements.  
         [0010]     While wheelchair trays and other conventional tray designs may be suitable for the particular purpose for which they serve, they are not as suitable for computer assisted living. Conventional wheelchair trays do not provide a robust means to support, secure, encase, and/or protect electronic devices. A portable computer or other electronic device that is simply placed onto the surface of a conventional wheelchair tray can easily fall from this mounting surface, potentially damaging the computer or injuring the computer user. Also, these electronics can be easily damaged by foreign elements such as liquids or foods which might accidentally spill onto the electronic device.  
         [0011]     Existing hand-held electronic devices can be difficult for a wheelchair user to hold while propelling a manual wheelchair or controlling an electronic wheelchair with a control joystick. In order for such electronic devices not be misplaced or damaged by wheelchair users, hand-held electronic devices have been affixed to wheelchairs with tubes or clamps, or attached to individuals&#39; arms with clips or Velcro®. However, these electronics can be damaged if water, soda or any foreign liquid get into the electronic devices&#39; protective enclosure.  
       OBJECTS AND ADVANTAGES OF THE INVENTION  
       [0012]     The present invention relates generally to a wheelchair tray and, more specifically, it relates to a modular multi-wall tray retrofitable to a wheelchair with provisions for housing various mechanical or electronic devices. The present invention generally comprises an engineered plastic tray, flexible trim molding along the outer perimeter of the tray and a mounting system means. The engineered sheet of plastic material utilized for the tray contains a hollow interior with a top and bottom panels joined by ribs and may be manufactured using traditional extrusion or injection molding techniques. One particular extruded plastic material is commonly referred to as a “multi-wall” panel. These multi-wall plastic panels are typically manufactured from polycarbonate or acrylic. Selection of the multi-wall material is novel for a wheelchair tray application due to the material&#39;s transparency, structural rigidity and low weight.  
         [0013]     Wheelchair trays made from existing prior art materials such as solid plastic may require a separate support means such as an aluminum rim secured to the perimeter of the tray or a separate metal bracket extended from the front of the wheelchair. Therafin Corporation&#39;s “Extenda-Arm” tray support is an example of prior art used to keep wheelchair trays from flexing downward during use with a heavy object. The primary benefit in the use of the multi-wall plastic material for a wheelchair tray is that this type of material does not require a separate element (made of aluminum or other rigid material) secured along its exterior to enhance the panel&#39;s rigidity. This multi-wall plastic material can support considerable weight without deflecting downward substantially when a load is applied to its top surface. This feature, combined with the fact that the wheelchair tray made of multi-wall plastic weighs less than one half the weight of a clear solid plastic tray with the same surface area, makes installation and removal of the tray from a wheelchair much easier for disabled individuals.  
         [0014]     Sometimes a conventional solid wheelchair tray must be secured more robustly to a wheelchair&#39;s armrest than with the standard Velcro® means wrapped entirely around the tray and wheelchair armrest. In the alternate mounting scenario, a pair of plastic or metal mounting brackets, which are designed and shaped to mount over the wheelchair armrest are attached to the underside of the wheelchair tray with screws, nuts, bolts or other mounting hardware. This tray/mounting bracket assembly is subsequently attached to the wheelchair armrests. Usage of such wheelchair tray mounting hardware typically requires that holes be drilled completely through the wheelchair tray; this, unfortunately, means that the top surface of a conventional wheelchair tray no longer has a smooth flush surface for the wheelchair user due to the exposed heads of the mounting screws. If a multi-wall wheelchair tray were used in place of the conventional solid wheelchair tray, the top surface of the tray would be perfectly smooth for the user with no exposed screws or Velcro™ straps.  
         [0015]     The internal openings in the tray provide a novel benefit: this open space can be utilized to house various mechanical, electronic and/or electro-mechanical devices. This feature not only keeps items within close-proximity to the user, but can also keep valuable electronics from being dropped or protecting the valuable electronics from solid or liquid contaminants. The inventions disclosed allow liquid or solid foods to be eaten, documents (either physical on the wheelchair tray or digital within a computer display) to be signed and read, or heavy objects to be placed onto its top surface of the tray without damaging the valuable electronic equipment housed inside. All of this can occur, while allowing the use of a fully-functional computer, cell phone, or other electronic accessories with enhanced communications and entertainment capabilities, as well as providing a comfortable and stable platform for the wheelchair user.  
         [0016]     Electronic devices can be protected inside the tray by a light-weight, flexible, low-durometer trim molding secured along the entire perimeter of the tray with a conventional adhesive. This preferred assembly technique can provide a robust water-resistant seal along the entire perimeter of the tray to an IP21 level of water and dust ingress protection or greater per IEC 60529. The benefit of such a seal is that electronics secured inside the internal openings of the modular wheelchair tray can be protected from contact with water or dust.  
         [0017]     A light-weight, flexible, low-durometer trim molding secured along the entire perimeter of the tray also provides safety benefits. Such trim molding can help to absorb the force of impact if, say, the wheelchair tray assembly is accidentally dropped. If dropped onto the ground, the edges and corners of the wheelchair tray are better protected from the impact; but, more importantly, if dropped onto a person&#39;s foot, less impact force will be imparted to the person. This trim molding, combined with the proposed light-weight wheelchair tray (which is 100%&#39;s lighter in weight than a traditional standard solid wheelchair tray due to the use of the multi-wall plastic material) will provide a safer wheelchair tray operating environment for wheelchair users and healthcare workers.  
         [0018]     The light-weight, flexible, low-durometer trim molding can be pigmented to produce various colors. However, if the trim molding is transparent or translucent, the tray can house a series of light emitting diodes along the tray&#39;s perimeter. The system can also be sealed from contaminants to prevent damage to the electronics.  
         [0019]     Inherent to the design of the wheelchair tray, power and data lines may be routed along the perimeter of the tray, between the tray material and the edge trim molding; these electrical connections can be individual wires or even integrated into a flex circuit.  
         [0020]     The electronics in the modular wheelchair tray are powered either by rechargeable batteries or by rechargeable batteries and solar cells to provide power without any external connections. The solar charging aspect of the present invention also allows the tray to charge the wheelchair, life support equipment, cell phones etc. Photovoltaic cells have achieved efficiencies approaching the 50% mark. The amount of surface area available in the modular wheelchair tray allows for many solar panels to be mounted inside the tray. This, combined with a connector port along the perimeter of the tray, allows many electronic devices to be powered by the tray&#39;s charging system.  
         [0021]     A modular multi-wall tray retrofitable to a wheelchair can function as an electronic device for personal training, entertainment, rehabilitation, or as an integrated communication platform with cell phone/wireless internet technology. At the same time, the tray may also function as a dinner tray or a document support for reading, etc. A modular multi-wall tray retrofitable to a wheelchair can be used by individuals with limited mobility in schools, hotels, businesses, meeting rooms, homes, nursing homes, manufacturing environments, hospitals, etc. The product allows users to listen to compact discs or MP3 players, view digital video disk (DVD) movies, play games, read and/or send e-mail from multiple viewing positions. As with many computer devices, wireless connectivity also exists for connection to the Internet or communication within a business environment (e.g. medical information tracking and billing). Integrated speakers and a microphone can also be incorporated into the tray, and the tray can be sealed along its perimeter to prevent infiltration of contaminants into the tray itself. In doing so, the product can function as a portal of communication between the user and the outside world from the confines of a wheelchair, and between the user and the healthcare professional if special needs exist, such as for hearing or visually impaired individuals.  
         [0022]     The term “electronic display” in this document describes a tablet Personal Computer (tablet PC, either convertible or slate), portable laptop/notebook computer, PDA, gaming console, cellular phone, flat panel television, flat panel monitor, a flexible display or other small-profile, microprocessor-controlled device. An electronic display can be an electronic device which contains either a liquid crystal display (LCD), plasma screen or TFT (thin-film transistor) screen and separate electronic hardware necessary to process, display and send/receive information to/from another remote computer processor. Another remote display technology (under 1/16″ thick) is an LCD or organic-light-emitting-diode (LED) flexible screen, which combines polymer and metal-foil substrates with printable TFT backplanes. The thinnest and most recent display screen technology is actually a flexible substrate known as E-ink, which is a screen thin enough to be integrated into a watch band.  
         [0023]     The remote viewing configuration of the remote display enables the electronic display to essentially function as a “dummy terminal”, without taking up the space typically required for a complete computer system. The remote display requires a separate remote computer processor to transmit the data, images or video to/from the remote display and may require a separate user-input device such as a keyboard, mouse, or keypad to control the information transmitted. The remote computer processor contains a Central Processing Unit (CPU) with corresponding auxiliary input and storage device(s). The remote computer processor also contains electronic hardware to transmit data to and receive data from the remote display via a wireless link (e.g. via 802.11b protocol, Bluetooth protocol) or a wired link (e.g. Cat. 6 RJ45 copper cable). One example of a remote display which functions in conjunction with a remote computer processor is the wireless Sony LocationFree™ TV product. In one embodiment described in this document, the remote display is mounted into the multi-wall wheelchair tray and the remote computer processor is placed within operating range of the remote display. This allows the wheelchair occupant to utilize a completely functional remote display without the added weight or clutter of a PDA, DVD player or computer attached to the wheelchair or wheelchair tray.  
         [0024]     Typically, electronic displays such as PDA&#39;s utilize a technology whereby a touch-screen display can be used as the sole computer input device. The primary input device on a tablet PC, however, differs from that found on a PDA. The stylus pen on a PDA is typically a passive pen-shaped instrument with no internal electronics that operates the microprocessor by depressing a touch-sensitive display screen. The stylus pen on a tablet PC, however, typically has electronics built in which allow the pen to operate the computer at a distance from the display screen without actually depressing the display screen, otherwise known as “hovering”. The tablet PC stylus pen can operate a computer while hovering from the display a distance of up to approximately 0.38 inch utilizing present-day technology. The invention described in this document utilizes this tablet PC stylus pen technology to an advantage not heretofore known and incorporates it into a robust wheelchair tray.  
         [0025]     Integration of electronic devices into the multi-wall tray can occur with a trim molding sealed with adhesive along the tray&#39;s outer perimeter. Such an assembly can create a water-resistant tray assembly with embodiment with at least an IP21 level of ingress protection per IEC 60529, “Degrees of Protection Provided by Enclosures (IP Code)” document by the International Electrotechnical Commission.  
         [0026]     The IEC 60529 document specifies a degree of protection 1) for persons against access to hazardous parts inside an enclosure and 2) for equipment inside an enclosure against a) the ingress of solid foreign objects and b) the harmful effects due to the ingress of water. The IP Code is a designation that indicates the level, or amount, of protection. The IP Code designation consists of the letter IP (International Protection) followed by two numerals. The first numeral of the IP Code (IPX_) indicates the degree of protection provided by the enclosure to persons having access to hazardous parts and with respect to solid foreign objects entering the enclosure; this first numeral is rated from a value of zero (0), which designates a non-protected device, to six (6), which designates a device with protection against access to hazardous parts with a wire and also designates a dust-tight device. The second numeral of the IP Code (IP_Y) indicates the degree of protection provided by the enclosure with respect to the harmful ingress of water entering the enclosure; this second numeral is rated from a value of zero (0), which designates a non-protected device, to eight (8), which designates a device with protection against the effects of continuous immersion of water.  
         [0027]     The IP21 level of protection designates that a device is protected against access to hazardous parts with a finger, protected against solid foreign objects=12.5 mm in diameter, and protected against vertical falling water drops. Many types of electronic devices normally placed across the top surface of a solid wheelchair tray can now have an additional layer of safety to an IP21 (or even greater) level of protection from the use of a multi-wall tray embodiment depicted in this document. This type of multi-wall tray design can be quite beneficial in a hospital or nursing home environment where foods and liquids are constantly in use.  
         [0028]     To further prevent objects from falling from the top surface of the tray, an optional raised flexible rim can extend from the top of the trim molding. This raised flexible rim can be a safety feature in the fact that it is a flexible rim, manufactured from a low-durometer plastic, unlike many traditional trays which utilize an aluminum rim. The durometer of the raised flexible rim material will prevent objects from falling from the top of the tray but will not cut or injure the user upon physical contact. The raised flexible rim can either be co-extruded with the trim molding or be secured as a separate component to the trim molding with any known traditional adhesive, heat bonding or ultrasonic welding processes.  
         [0029]     Mounting systems to secure the multi-wall tray assembly to the wheelchair using traditional Velcro® straps, traditional rigid mounting hardware and a prior art tubular mounting system is also employed.  
         [0030]     In these respects, a modular multi-wall tray retrofitable to a wheelchair according to the present inventions substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus developed for the purpose of enhanced safety, computer-assisted living, computer assisted communication, business and/or entertainment.  
         [0031]     In view of the foregoing disadvantages inherent in the known types of wheelchair trays now present in the prior art, the present invention provides a new modular wheelchair tray which secures a computer, communications and other electronic devices in a design and construction wherein the same can be utilized for computer assisted living. The present invention provides a modular multi-wall tray retrofitable to a wheelchair that will overcome the shortcomings of the prior art devices.  
         [0032]     The general purpose of the present inventions, which will be described subsequently in greater detail, is to provide a new modular wheelchair tray that has many of the advantages of conventional solid wheelchair trays and many novel features that result in a new modular multi-wall tray retrofitable to a wheelchair which is not anticipated, rendered obvious, suggested, or even implied by any prior art, either alone or in any combination thereof.  
       SUMMARY OF THE INVENTION  
       [0033]     A specific embodiment of the present invention provides a wheelchair tray which comprises an engineered multi-wall tray, edge trim molding and a mounting system. The engineered multi-wall tray has a top panel and bottom panel joined by support members; the internal cross-section is essentially comprised of ribs spaced between openings that can also serve as storage compartments. The tray can be manufactured using traditional extrusion or injection molding techniques. The types of plastic recommended for use in this design are polycarbonate or acrylic. The multi-wall material is the preferred choice for this application because of its transparency, structural strength and low weight. More importantly, the multi-wall material provides a robust tray which is self-supporting and lighter in weight than conventional trays. Edge trim molding can be added to the perimeter of the tray to provide a raised lip to prevent objects from falling off the top of the multi-wall tray, to cap the ends of the tabletop for aesthetic or cleanliness purposes, or to help absorb the impact force of a falling tray onto a person&#39;s extremities.  
         [0034]     Conventional wheelchair trays contain similar design methodologies to secure wheelchair trays to wheelchair armrests. Several of the design elements presented in this document utilize conventional wheelchair tray mounting means in a fashion not previously conceived for use with multi-wall trays. Conventional mounting means to secure the multi-wall wheelchair tray to a wheelchair may include Velcro® straps or rigid mounting hardware. The use of the multi-wall material allows the proposed tray to be mounted to a wheelchair using these conventional means with a very practical benefit: the wheelchair tray hardware can be secured to the bottom panel of the multi-wall tray, providing a smooth top panel work surface. Another novel mounting means embodiment presented allows the multi-wall tray to be rotated away and folded to the side of the wheelchair wheel when not in use.  
         [0035]     The geometry of the multi-wall material allows various mechanical and electronics devices to be installed into the openings inside the tray. The tray can therefore be used as a protective enclosure. If the multi-wall panel is combined with an edge trim molding that is sealed along the perimeter of the tray, the tray can be used as a dust-resistant and water-resistant enclosure to IP21 per document IEC 60529.  
         [0036]     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways.  
         [0037]     It is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting. Other objects and advantages of the present invention will become obvious to the reader and it is intended that these objects and advantages are within the scope of the present invention.  
         [0038]     To the accomplishment of the above and related objects, this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only and that changes may be made in the specific construction illustrated.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0039]     Various other objects, features and attendant advantages of the present invention will become fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:  
         [0040]      FIG. 1  is an isometric view of the preferred I-Tray embodiment.  
         [0041]      FIG. 2  is an exploded isometric view of the preferred I-Tray embodiment.  
         [0042]      FIG. 3  is a plan view of the multi-wall tray.  
         [0043]      FIG. 4  contains isometric views of the preferred edge trim molding shape and the preferred edge trim molding installed onto a multi-wall panel.  
         [0044]      FIG. 5  is an isometric view of the I-Tray embodiment assembled to wheelchair armrests.  
         [0045]      FIG. 6  is a partial bottom isometric view of the I-Tray embodiment assembled to wheelchair armrests.  
         [0046]      FIG. 7  is an isometric view of the I-Tray embodiment with slotted cutouts and Velcro™.  
         [0047]      FIG. 8  is a bottom isometric view of the I-Tray embodiment with slotted cutouts and Velcro™ assembled to wheelchair armrests.  
         [0048]      FIG. 9  is an isometric view of a Velcro™ strap formed into a hem.  
         [0049]      FIG. 10  is a partial cross-sectional view of the I-Tray embodiment with slotted cutouts and hemmed Velcro™ installed.  
         [0050]      FIG. 11  is a bottom front isometric view of the I-Tray embodiment with slotted cutouts and hemmed Velcro™ assembled to the armrest of a wheelchair.  
         [0051]      FIG. 12  is a bottom front isometric view of the bracket mounting means embodiment assembled to the armrest of a wheelchair.  
         [0052]      FIG. 13  is an exploded bottom isometric view of the bracket mounting means embodiment.  
         [0053]      FIG. 14  is a top view of the multi-wall tray with a joystick control cutout.  
         [0054]      FIG. 15  is an isometric view of the rectangular multi-wall tray.  
         [0055]      FIG. 16  is an isometric view of the Eco-Tray embodiment.  
         [0056]      FIG. 17  is an isometric view of the low-cost Eco-Tray mounting means embodiment.  
         [0057]      FIG. 18  is an exploded isometric rear view of the fold away Eco-Tray mounting means embodiment around the upper support assembly.  
         [0058]      FIG. 19  is an exploded isometric view of the fold away Eco-Tray mounting means embodiment.  
         [0059]      FIG. 20  is an exploded isometric view of the upper support assembly.  
         [0060]      FIG. 21  is an exploded isometric view of the lower support assembly.  
         [0061]      FIG. 22  is an exploded isometric view of the standard inner mounting clamp assembled to the short clamping tube and the wheelchair frame.  
         [0062]      FIG. 23  is an exploded isometric view of the standard outer mounting clamp assembled to the short clamping tube and lower support assembly.  
         [0063]      FIG. 24  is an isometric view of the fold away Eco-Tray mounting means embodiment assembled to the wheelchair frame.  
         [0064]      FIG. 25  is an isometric view of the fold away Eco-Tray mounting means embodiment assembled to the wheelchair.  
         [0065]      FIG. 26  is an isometric view of the fold away Eco-Tray mounting means embodiment assembled to the wheelchair and rotated 180 degrees.  
         [0066]      FIG. 27  is a top view of the fold away Eco-Tray mounting means embodiment assembled to the wheelchair and rotated 180 degrees.  
         [0067]      FIG. 28  is an isometric view of the fold away Eco-Tray mounting means embodiment assembled to the wheelchair and rotated 270 degrees in a fold-away orientation.  
         [0068]      FIG. 29  is a top view of the fold away Eco-Tray mounting means embodiment assembled to the wheelchair and rotated 270 degrees in a fold-away orientation.  
         [0069]      FIG. 30  is an end view of an alternate multi-wall tray material with three panels and additional diagonal support rib.  
         [0070]      FIG. 31  is an end view of the preferred multi-wall tray material.  
         [0071]      FIG. 32  is an end view of an alternate multi-wall tray material with three panels.  
         [0072]      FIG. 33  is an exploded isometric view of the hinge from the folding tray embodiment.  
         [0073]      FIG. 34  contains end views of various edge trim molding shapes.  
         [0074]      FIG. 35  contains end views of the preferred edge trim molding shapes.  
         [0075]      FIG. 36  is an isometric view of the multi-wall tray cup holder embodiment.  
         [0076]      FIG. 37  is a partial cross-sectional view of a cup installed into the multi-wall tray cup holder embodiment.  
         [0077]      FIG. 38  is an isometric view of the folding tray embodiment in an unfolded orientation.  
         [0078]      FIG. 39  is an isometric view of the folding tray embodiment in a folded orientation.  
         [0079]      FIG. 40  is a top view of the Ad-Tray embodiment.  
         [0080]      FIG. 41  is an exploded isometric view of the Ad-Tray embodiment.  
         [0081]      FIG. 42  is a top view of the carrying handle embodiment.  
         [0082]      FIG. 43  is a partially exploded isometric view of the carrying handle embodiment.  
         [0083]      FIG. 44  is an isometric view of the electronics docking station embodiment with an Apple iPod® Shuffle™ awaiting installation.  
         [0084]      FIG. 45  is an isometric view of the electronics docking station embodiment with the top panel removed and an Apple iPod® Shuffle™ installed.  
         [0085]      FIG. 46  is an exploded top view of the electronics docking station embodiment with an Apple iPod® Shuffle™.  
         [0086]      FIG. 47  is an isometric view of the solar panel charging system embodiment with the top panel and edge trim molding removed.  
         [0087]      FIG. 48  is an isometric view of the solar panel charging system embodiment with an installed cellular phone.  
         [0088]      FIG. 49  is a top view of the solar panel charging system embodiment with the top panel edge trim molding removed.  
         [0089]      FIG. 50  is a bottom isometric view of the electronic display embodiment.  
         [0090]      FIG. 51  is an exploded bottom isometric view of the electronic display embodiment.  
         [0091]      FIG. 52  is a block diagram of the solar panel embodiment.  
     
    
       [0092]     The following is a list of reference symbols as set forth in the foregoing Specification:  
         [0000]     Numerals Refers to:  
         [0000]    
       
           1  “I-Tray” embodiment  
           2  Multi-wall tray  
           3  Edge trim molding  
           4  Top panel of multi-wall tray  
           5  Bottom panel of multi-wall tray  
           6  Connecting support ribs  
           7  Rectangular “torso” cutout  
           8  Left arm extension of multi-wall tray  
           9  Right arm extension of multi-wall tray  
           10  Perimeter of the multi-wall tray  
           11  Internal corner radii of multi-wall tray  
           12  External corner radii of multi-wall tray  
           13  “C” shape of edge trim molding  
           14  Hollow openings of multi-wall tray  
           15  Left wheelchair armrest  
           16  Right wheelchair armrest  
           17  Double-sided Velcro® strap  
           18  Double-sided Velcro® strap  
           19  Top of I-Tray  
           20  Bottom of left wheelchair armrest  
           21  Bottom of right wheelchair armrest  
           22  Slotted cutout in left arm extension  
           23  Slotted cutout in left arm extension  
           24  Slotted cutout in right arm extension  
           25  Slotted cutout in right arm extension  
           26  Alternate double-sided hemmed Velcro® strap  
           27  Distal end of alternate double-sided Velcro® strap  
           28  Hem of alternate double-sided Velcro® strap  
           29  First Velcro® mounting means embodiment  
           30  Second Velcro® mounting means embodiment  
           31  Wheelchair tray mounting bracket  
           32  Bracket mounting means embodiment  
           33  Clearance holes in bottom panel of multi-wall tray  
           34  Mounting inserts inside multi-wall tray  
           35  Screws for mounting brackets  
           36  Female receptacles in mounting inserts  
           37  Internally threaded fastener in mounting insert  
           38  Screw mounting holes in conventional wheelchair tray mounting bracket  
           39  Wheelchair  
           40  Tray front corner  
           41  Joystick control cutout  
           42  “Eco-Tray” embodiment  
           43  Multi-wall rectangular tray  
           44  Top panel of multi-wall rectangular tray  
           45  Bottom panel of multi-wall rectangular tray  
           46  Connecting support ribs of multi-wall rectangular tray  
           47  Hollow openings of multi-wall rectangular tray  
           48  External corner radii of multi-wall rectangular tray  
           49  Perimeter of multi-wall rectangular tray  
           50  Slotted cutouts in multi-wall rectangular tray  
           51  Distal end of the multi-wall tray  
           52  “Fold Away Eco-Tray Mounting Means” embodiment  
           53  Eco-Tray assembly with brackets and inserts  
           54  “Half-moon” Eco-Tray mounting bracket  
           55  Holes in “half-moon” Eco-Tray mounting bracket  
           56  Eco-Tray mounting bracket  
           57  Spring-loaded plunger  
           58  Knob of spring-loaded plunger  
           59  Spring-loaded plunger tip  
           60  Standard push button  
           61  Button  
           62  Outermost left edge of Eco-Tray assembly  
           63  Left wheel of wheelchair  
           64  Upper support assembly  
           65  Lower support assembly  
           66  Standard inner mounting clamp  
           67  Short clamping tube  
           68  Short vertical tube  
           69  Horizontal tube  
           70  Tube collar  
           71  Slot  
           72  Hole  
           73  Threaded hole  
           74  Set screw  
           75  Bent tube  
           76  Spring-loaded plunger  
           77  Hole in bent tube  
           78  Tip of spring-loaded plunger  
           79  Standard outer mounting clamp  
           80  Top clamp section  
           81  Center clamp section  
           82  Bottom clamp section  
           83  Fasteners  
           84  Circular recesses  
           85  Wheelchair frame  
           86  Threaded holes  
           87  Top clamp section  
           88  Center clamp section  
           89  Bottom clamp section  
           90  Fasteners  
           91  Circular recesses  
           92  Top end of bent tube  
           93  Clearance holes  
           94  Threaded holes  
           95  Hole in short vertical tube  
           96  Hole in tube collar  
           97  End of horizontal tube  
           98  Clearance holes in top clamp section  
           99  Right wheel of wheelchair  
           100  Bend at an angle on “half-moon” Eco-Tray mounting bracket  
           101  Flat surface of “half-moon” Eco-Tray mounting bracket  
           102  Cutout at the center of “half-moon” Eco-Tray mounting bracket  
           103  Curved surface of Eco-Tray mounting bracket  
           104  Short mounting inserts  
           105  Fasteners  
           106  Clearance holes in “half-moon” Eco-Tray mounting bracket  
           107  Clearance holes in Eco-Tray mounting bracket  
           108  Clearance holes in multi-wall rectangular tray  
           109  I-shaped cross sections of multi-wall trays  
           110  Additional panels  
           111  Alternate rib angles  
           112  Circular hole  
           113  Cup  
           114  Folding tray embodiment  
           115  Left tray half  
           116  Hinge  
           117  Right tray half  
           118  Radiused edges of hinge  
           119  Ad-Tray embodiment  
           120  Printable material  
           121  Carrying handle embodiment  
           122  Handle  
           123  Holes for handle  
           124  Flat surface of Eco-Tray mounting bracket  
           125  Electronics docking station embodiment  
           126  Apple iPod® Shuffle™ 
           127  Electronics docking multi-wall tray  
           128  Small support rib  
           129  Circular mounting hole in small support rib  
           130  Stereo male plug  
           131  Circular cutout in bottom panel  
           132  Top panel of electronics docking multi-wall tray  
           133  Bottom panel of electronics docking multi-wall tray  
           134  Speakers  
           135  Wires in electronics docking multi-wall tray  
           136  Opening in electronics docking multi-wall tray  
           137  Wheelchair user side of electronics docking multi-wall tray  
           138  Far side perimeter edge  
           139  Optional wire recess groove  
           140  Solar panel charging system embodiment  
           141  Solar panel arrays  
           142  Openings in solar panel multi-wall tray  
           143  Solar panel multi-wall tray  
           144  Battery pack  
           145  Charging port  
           146  Cellular phone with charging cable  
           147  Voltage regulator between solar panel arrays and battery pack  
           148  Cable  
           149  Optional wire recess groove  
           150  Plastic housing  
           151  Voltage regulator between battery pack and charging port  
           152  Far side perimeter edge of solar panel multi-wall tray  
           153  Electronic display embodiment  
           154  Electronic display multi-wall tray  
           155  Rectangular cutout  
           156  Bottom panel of electronic display multi-wall tray  
           157  Electronic display  
           158  Rear side of top panel from electronic display multi-wall tray  
           159  Screen of electronic display  
           160  Mounting plate  
           161  Fasteners  
           162  Holes in mounting plate  
           163  Optional rubber gasket  
           164  Optional USB port with cable  
           165  Hole for USB port  
           166  Hinge pin  
           167  Left hinge section  
           168  Right hinge section  
           169  Holes in left hinge knuckle  
           170  Holes in right hinge knuckle  
           171  Mounting flat of left hinge section  
           172  Mounting flat of right hinge section  
           173  Connector from USB port with cable  
           174  USB port from electronic display  
           175  Alternative multi-wall configurations  
           176  Alternative edge trim moldings  
           177  Raised flexible rim  
           178  Wheelchair user vantage point  
       
     
       DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0271]     Turning now descriptively to the drawings, in which similar referenced characters denote similar elements throughout the several views, the attached figures illustrate the multi-wall wheelchair tray. This embodiment is termed the “I-Tray”  1 , due to the I-beam shape of the internal support structure.  
         [0272]     The I-Tray embodiment  1  shown in  FIGS. 1 and 2  is comprised of three main elements:  
         [0273]     1) multi-wall tray  2   
         [0274]     2) edge trim molding  3   
         [0275]     3) double-sided Velcro® straps  17 , 18   
         [0276]     The multi-wall tray  2  shown in  FIG. 3  is preferably made of a contiguous plastic or carbon fiber panel which has a) a top panel  4 , b) a bottom panel  5 , and c) connecting support ribs  6 . As a result of this design, the multi-wall tray  2  has hollow openings  14 .  
         [0277]     The shape of the multi-wall tray  2  is defined in the layout shown in  FIG. 3  and is similar to other industry-standard wheelchair trays. The multi-wall tray  2  contains a rectangular “torso” cutout  7  that contours around a wheelchair occupant&#39;s body, one left arm extension  8 , and one right arm extension  9 . The perimeter  10  of the multi-wall tray  2  is contoured at the corners with internal corner radii  11  and external corner radii  12  to provide comfort to the wheelchair occupant. Dimensions C, D, E, F, G, H, I, J and K are only guidelines to establish the overall shape of the multi-wall wheelchair tray  2 . For reference, if the multi-wall wheelchair tray  2  was used with an adult wheelchair occupant, dimension C could be 23 inches, dimension D could be 22 inches, dimension E could be 13.5 inches, dimension F could be 9 inches, dimension G could be 4.75 inches, dimension H could be 0.63 inch, dimension I could be 1.5 inches, dimension J could be 1 inch, and dimension K could be 0.06 inches. Dimension I is representative of the internal  11  and external  12  corner radii of the multi-wall tray  2 .  
         [0278]     The edge trim molding  3  is preferably made of plastic or rubber and has a general “C” shape  13 . See  FIG. 4 . In the preferred embodiment, the edge trim molding  3  assembles to the perimeter  10  of the multi-wall tray  2  with traditional adhesives, heat bonding, or ultrasonic welding processes. Any of the following traditional adhesives can be used: cyanoacrylate, urethane, epoxy (2-part or heat-cured), acrylic (1 part, 2-part or UV-curable) or anaerobic. The use of an adhesive ensures that foreign contaminants do not enter into the openings  14  in the multi-wall tray  2 .  
         [0279]     The I-Tray  1  embodiment is secured across the top of the left wheelchair armrest  15  and right wheelchair armrest  16  with the industry-standard attachment means. See  FIGS. 5 and 6  (which has parts of the wheelchair  39  removed for clarity). The industry-standard mounting means requires the use of double-sided Velcro® straps  17 ,  18  wrapped across the top  19  of the I-Tray  1  and across the bottom  20  of the left wheelchair armrest  15  and the bottom  21  of the right wheelchair armrest  16 .  
       Description of Alternative Velcro® Mounting Means Embodiments  
       [0280]     The I-Tray embodiment  1  can be secured to the wheelchair in novel ways that do not expose the wheelchair user&#39;s arms to the rough surface of the Velcro® straps  17 ,  18 . In the first Velcro® mounting means embodiment  29 , the bottom panel  5  of the I-Tray  1  contains two pairs of slotted cutouts  22 ,  23 ,  24 ,  25 . See  FIG. 7 . The first pair of slotted cutouts  22 ,  23  is located on the bottom panel  5  of the left arm extension  8  and the second pair of slotted cutouts  24 ,  25  is located on the bottom panel  5  of the right arm extension  9 . One Velcro® strap  17  is positioned into the first slotted cutout  22  of the left arm extension  8  and then fed thru the second slotted cutout  23  of the left arm extension  8 . The Velcro® strap  17  is then wrapped around the bottom  20  of the left wheelchair armrest  15 . The same task is performed with a second Velcro® strap  18  fed through the second pair of slotted cutouts  24 ,  25  in the bottom panel  5  of the right arm extension  9 . This second Velcro® strap  18  is then also wrapped around the bottom  21  of the right wheelchair armrest  16 , completing assembly of the first Velcro® mounting means embodiment  29 . See  FIG. 8  for a view of the final assembly with the wheelchair  39  removed for clarity.  
         [0281]     In a second Velcro® mounting means embodiment  30 , a double-sided Velcro® (strap  26  can have one end stitched or folded back onto itself to form a hem  28 . See  FIG. 9  with edge molding  3  removed for clarity. The hem  28  of this double-sided hemmed Velcro® strap  26  can be fed into the slotted cutouts  22 ,  23 ,  24 ,  25  at the bottom  5  of the I-Tray  1 . Once inside the opening  14  of the tray, the hem  28  acts as a retention means, preventing the double-sided hemmed Velcro® strap  26  from releasing from any of the slotted cutouts  22 ,  23 ,  24 ,  25  when a force is applied to the distal end  27  of the double-sided hemmed Velcro® strap  26 . See  FIG. 10  with edge molding  3  removed for clarity. This alternate assembly embodiment provides a secure means to retain the double-sided hemmed Velcro® strap  26  to the bottom  5  of the I-Tray  1 . To assemble the second Velcro® mounting means embodiment  30  to the I-Tray  1 , the distal ends  27  of two adjacent double-sided hemmed Velcro® strap  26  would be wrapped around the bottom  20 ,  21  of the wheelchair armrests  15 ,  16  and secured to one another. See  FIG. 11  for final installation.  
       Description of Alternative Bracket Mounting Means Embodiment  
       [0282]     Any wheelchair tray mounting bracket  31  can be rigidly secured to the bottom panel  5  of the multi-wall tray  2  in a novel way that does not expose the wheelchair user to an uneven tray surface or expose one to any mounting screws along the top of the tray.  
         [0283]     The alternative bracket mounting means embodiment  32  is comprised of five main elements shown in  FIGS. 12 and 13 :  
         [0284]     1) multi-wall tray  2   
         [0285]     2) screw clearance holes  33  in multi-wall tray bottom panel  5   
         [0286]     3) mounting inserts  34   
         [0287]     4) wheelchair tray mounting brackets  31   
         [0288]     5) screws  35   
         [0289]     6) optional edge trim molding  3   
         [0290]     The mounting inserts  34  depicted in  FIG. 13  are preferably made of plastic or metal, which a) are shaped and sized (preferably rectangular in cross-section) to fit into the hollow openings  14  of the multi-wall tray  2  and b) contain female receptacles  36  to accept screws  35 , preferably of the flat head type. The female receptacle  36  (preferably two in quantity) in each mounting insert  34  is a simple hole with a separate internally threaded fastener  37  assembled into the female receptacle  36 . Alternatively, the female receptacle  36  can be any of several conventional types, including a nut or simply a tapped hole that accepts the screw  31 .  
         [0291]     The mounting inserts  34  are installed into the hollow openings  14  in the multi-wall tray  2 . The female receptacles  36  in the mounting inserts  34  are aligned above the corresponding screw clearance holes  33  in the bottom panel  5  of the multi-wall tray  2 . The wheelchair tray mounting brackets  31  are then positioned such that the screw mounting holes  38  in the mounting brackets  31  are also aligned above the corresponding screw clearance holes  33  in the bottom panel  5  of the multi-wall tray  2 .  
         [0292]     The preferably flat head screws  35  are installed through the screw mounting holes  39  in the wheelchair tray mounting brackets  31 , through the clearance holes  33  in the bottom panel  5  of the multi-wall tray  2  and then fastened to the female receptacles  36  and corresponding internally threaded fasteners  37  found in the mounting inserts  34 . Final assembly of the bracket mounting means embodiment  32  is shown in  FIG. 12 . The wheelchair tray mounting brackets  31  and correspondingly attached multi-wall tray  2  are then slid over the wheelchair armrests  15 ,  16  to secure the bracket mounting embodiment  32  to the wheelchair  39 .  
       Description of Alternate Tray Size Embodiment  
       [0293]     Alternate dimensional sizes of the multi-wall tray  2  are possible beyond those depicted in the preferred I-tray embodiment  1 . If the multi-wall tray  2  were to be used on a child&#39;s wheelchair, the tray size could be modified to better contour around the torso of a smaller person; in this case, the values for dimensions E and F from  FIG. 3  would be decreased. In addition, the overall size of the tray could be modified to fit onto a wide-body wheelchair which has wheelchair armrests  15 ,  16  further apart from one another; in this case, the overall width of the multi-wall tray, dimension C, and corresponding dimension G would be increased.  
       Description of Optional Control Cutout Embodiment  
       [0294]     The multi-wall tray  2  can be manufactured with a front corner  40  that has a joystick control cutout  41 , as depicted in  FIG. 14 . The multi-wall tray  2  with added joystick control cutout  41  is shown with added edge trim molding  3 . The rectangular-shaped joystick control cutout  41  would be used on electric wheelchairs which utilize an electronic joystick control for navigation. The joystick control cutout  41  is essentially clearance on the multi-wall tray  2  for the wheelchair user to be able to access the joystick control.  
       Description of Rectangular Eco-Tray Embodiment  
       [0295]     The multi-wall material can also be used to create a tray with a simple rectangular shape. This embodiment is termed the “Eco-Tray”  42 , due to the ecologically-friendly and economical use of less plastic in this tray embodiment.  
         [0296]     The Eco-Tray embodiment  42  shown in  FIGS. 15 and 16  is comprised of two main elements:  
         [0297]     1) multi-wall rectangular tray  43   
         [0298]     2) edge trim molding  3   
         [0299]     The multi-wall rectangular tray  43  shown in  FIG. 15  has a similar structure as the multi-wall tray  2  in the I-Tray embodiment  1 . The multi-wall rectangular tray  43  is preferably made of a contiguous plastic or carbon fiber panel which also has a) a top panel  44 , b) a bottom panel  45 , and c) connecting support ribs  46 . This multi-wall rectangular tray  43 , similar to the multi-wall tray  2 , also has hollow openings  47 .  
         [0300]     The multi-wall rectangular tray  43 , as its name implies, has a generally rectangular shape. The perimeter  49  of the multi-wall rectangular tray  43  is also contoured at each of the four corners with external corner radii  48 . An edge trim molding  3  can also be assembled to the perimeter  49  of the multi-wall rectangular tray  43  to complete the Eco-Tray embodiment  42 .  
       Description of Low-Cost Eco-Tray Mounting Means Embodiment  
       [0301]     The Eco-Tray embodiment  42  can be used as a normal T.V. (a.k.a. television) lap tray when sitting on a couch, so the mounting means to attach the Eco-Tray embodiment  42  to a wheelchair or other device are considered optional. The Eco-Tray embodiment  42  could be attached to the wheelchair armrests  15 ,  16  with any of the aforementioned Velcro® embodiments  29 ,  30  or mounting bracket embodiments  32 . Suffice it is to say that the multi-wall rectangular tray  43  from the Eco-Tray embodiment  42  would need to be modified for the aforementioned embodiments  29 ,  30 ,  32  to be secured to the left and right wheelchair armrests  15 ,  16 . The bottom panel  45  of the Eco-Tray embodiment  42  would require either slotted cutouts  50  to function with the Velcro® embodiments  29 ,  30  or clearance holes to function with the mounting bracket embodiments  32  (latter not shown). See  FIG. 17  for view of the bottom panel  45  of the Eco-Tray with slotted cutouts  50 .  
       Description of a Fold Away Eco-Tray Mounting Means Embodiment  
       [0302]     The following embodiment claims the benefit of U.S. patent application Ser. No. 11/200,838, entitled “Modular Tube and Table Retrofitable to a Wheelchair”.  
         [0303]     The Eco-Tray embodiment  42  can be used in conjunction with a prior art means to secure a tray to a wheelchair. This novel embodiment is entitled “Fold Away Eco-Tray Mounting Means”  52  and is depicted in FIGS.  18  thru  29 .  
         [0304]     The fold away Eco-Tray mounting means embodiment  52  is comprised of six main elements:  
         [0305]     1) Eco-Tray assembly with brackets and inserts  53   
         [0306]     2) upper support assembly  64   
         [0307]     3) lower support assembly  65   
         [0308]     4) standard inner mounting clamp  66   
         [0309]     5) short clamping tube  67   
         [0310]     6) standard outer mounting clamp  79   
         [0000]     The fold away Eco-Tray mounting means embodiment  52  for mounting the Eco-Tray  42  contains:  
         [0311]     1) The Eco-Tray assembly with brackets and inserts  53 , depicted  FIGS. 18 and 19 , comprised of: 
        multi-wall rectangular tray  43      “half-moon” Eco-tray mounting bracket  54      Eco-Tray mounting bracket  56      short mounting inserts  104      fasteners  105      edge trim molding  3         
 
         [0318]     The “half-moon” Eco-Tray mounting bracket  54  is preferably made of metal or plastic, which has a) a bend at an angle  100 , b) a flat surface  101  for mounting to the bottom panel  45  of the multi-wall rectangular tray  43  c) a cutout at the center  102  for mounting to the horizontal tube  69  from the upper support assembly  64 , and d) holes  55  spaced evenly along an arc to engage the retractable, spring-loaded plunger  57  from the upper support assembly  64  for tilting the multi-wall rectangular tray  43 .  
         [0319]     The Eco-Tray mounting bracket  56  is preferably made of metal or plastic that a) has a curved surface  103  (for mounting to the horizontal tube  69  from the upper support assembly  64 ) and b) flat surfaces  124  to mount to the bottom panel  45  from the multi-wall rectangular tray  43 .  
         [0320]     Assembly of the Eco-Tray assembly with brackets and inserts  53  is as follows, per  FIG. 18 . First, the short mounting inserts  104  are installed into the hollow openings  47  of the multi-wall rectangular tray  43 . The short mounting inserts  104  are essentially shorter versions of the mounting inserts  34  described previously. The “half-moon” Eco-Tray mounting bracket  54  and the Eco-Tray mounting bracket  56  are positioned along the bottom panel  45  of the multi-wall rectangular tray  43 . Fasteners  105  are installed through the a) clearance holes  106  in the “half-moon” Eco-Tray mounting bracket  54 , b) clearance holes  107  in the Eco-Tray mounting bracket  56  and c) additional clearance holes  108  in the multi-wall rectangular tray  43 . The fasteners  105  are then threaded into the receptacles  36  from the short mounting inserts  104 , securing the brackets  54 ,  56  to the bottom panel  45  of the multi-wall rectangular tray  43 . The final assembly step of the Eco-Tray assembly with brackets and inserts  53  is the addition of the edge trim molding  3  to the perimeter  49  of the multi-wall rectangular tray  43 .  
         [0321]     Note that the short mounting inserts  104  and fasteners  105  are the most rigid means of securing the “half-moon” Eco-Tray mounting bracket  54  and the Eco-Tray mounting bracket  56  to the bottom panel  45  of the multi-wall tray  43 . Alternatively, the brackets  54 ,  56  can also be attached to the bottom panel  45  of the multi-wall tray  43  without use of the short mounting inserts  104 ; these brackets  54 ,  56  can also be assembled to the bottom panel  45  of the multi-wall rectangular tray  43  by means of Velcro®, a pressure-sensitive adhesive (i.e. PSA), welds, self-clinching screws, self-clinching nuts, double-sided tape, rivets, or with any known prior art mounting techniques.  
         [0322]     2) The upper support assembly  64 , depicted in  FIGS. 19 and 20 , which is comprised of: 
        short vertical tube  68      horizontal tube  69      retractable, spring-loaded plunger  57      tube collar  70      standard push-button  60         
 
         [0328]     The upper support assembly  64 , comprised of five main components, a) supports the underside of the Eco-Tray assembly with brackets and inserts  53 , b) telescopes inside of the lower support assembly  65  for vertical height adjustment and c) rotates inside of the lower support assembly  65  to allow the Eco-Tray assembly with brackets and inserts  53  to be oriented away from the wheelchair. Rotating the Eco-Tray assembly with brackets and inserts  53  away from the front of the wheelchair allows an individual to enter and exit the wheelchair without difficulty—see additional FIGS.  26  to  28 .  
         [0329]     The short vertical tube  68 , preferably made of metal, aluminum, fiberglass or plastic, a) is a section of rectangular, square or round tube (as shown in  FIG. 20 ), b) is generally vertical, c) contains a slot  71  (or thru holes, not shown) for accepting the front tip  78  of a retractable, spring-loaded plunger  76  from the lower support assembly  65  (see  FIG. 21 ).  
         [0330]     The horizontal tube  69 , preferably made of metal, aluminum, fiberglass or plastic, a) is a section of rectangular, square or round tube, b) is positioned roughly orthogonal to the short vertical tube  68 , and c) contains a hole  72  for a standard push button  60 , as depicted in  FIG. 20  (or for use with a spring-loaded ball plunger—not shown).  
         [0331]     A retractable, spring-loaded plunger  57 , typically of metal construction, a) is threaded into a tapped hole  95  in the short vertical tube  68 , b) has a spring-loaded plunger tip  59  which engages into the holes  55  from the “half-moon” mounting bracket  54  from the Eco-Tray assembly with brackets and inserts  53  when fully extended, and c) has a knob  58  (or pull-ring not shown) for retracting the spring-loaded plunger tip  59 . See  FIGS. 19 and 20 .  
         [0332]     When the knob  58  from the retractable, spring-loaded plunger  57  is pulled, the spring-loaded plunger tip  59  disengages from the holes  55  in the “half-moon” Eco-Tray mounting bracket  54  allowing the Eco-Tray assembly with brackets and inserts  53  to rotate about the horizontal tube  69 . This provides the wheelchair user multiple desired viewing, working, and reading angles.  
         [0333]     The tube collar  70 , of standard construction, as shown in  FIG. 20 , generally has a round shape with an inner hole  96  (circular inner hole shown, but can be other shapes based on the short vertical tube  68  shape) which allows the short vertical tube  68  to mount into the tube collar  70 . The tube collar  70  also has a threaded hole  73  which allows a set screw  74  to tighten into it. After installation of the short vertical tube  68  into the tube collar  70 , the set screw  74  can be tightened, thereby fastening the tube collar  70  onto the short vertical tube  68 .  
         [0334]     The standard push-button  60 , of standard construction, is located inside the horizontal tube  69  at the end  97  for retaining Eco-Tray assembly with brackets and inserts  53  onto the horizontal tube  69 . The standard push-button  60  inside of the horizontal tube  69  has one button  61  inside of the hole  72  from the horizontal tube  69 . In a default position, the button  61  protrudes beyond the exterior surface of the horizontal tube  69 . In this configuration, the protruding button  61  prevents the Eco-Tray mounting bracket  56  of the Eco-Tray assembly with brackets and inserts  53  from sliding off of the horizontal tube  69 , thereby securing the associated Eco-Tray assembly with brackets and inserts  53 . (See  FIG. 18  for detailed views of the Eco-Tray assembly with brackets and inserts  53 .) Pushing the button  61  inward allows the Eco-Tray mounting bracket  56  and Eco-Tray assembly with brackets and inserts  53  associated to slide off the horizontal tube  69 , thus allowing the product to be disassembled.  
         [0335]     3) The lower support assembly  65  depicted in  FIGS. 19 and 21  is comprised of: 
        bent tube  75      retractable, spring-loaded plunger  76         
 
         [0338]     The bent tube  75 , preferably made of metal, aluminum, fiberglass or plastic a) is a section of rectangular, square or round tube (shown), b) contains a roughly 30 degree bend and c) contains a hole  77  to mount the retractable, spring-loaded plunger  76 . The retractable, spring-loaded plunger  76  can be attached to the bent tube  75  with welds, screws, nuts, self-clinching screws, self-clinching nuts, rivets, or with any known prior art mounting techniques.  
         [0339]     The following paragraph describes the use and movement of the upper support assembly  64  relative to the lower support assembly  65 . The short vertical tube  68  from the upper support assembly  64  is slid into the top end  92  of the bent tube  75  from the lower support assembly  65 . The tube collar  70  fastened to the short vertical tube  68  from the upper support assembly  64  stops the upper support assembly  64  from dropping down into the lower support assembly  65 . The upper support assembly  64  and corresponding Eco-Tray assembly with brackets and inserts  53  can be raised or lowered relative to the lower support assembly  65  by unscrewing the set screw  74 , adjusting the height of assemblies  53  and  64  accordingly, and tightening the set screw  74 . To rotate the upper support assembly  64  and corresponding Eco-Tray assembly with brackets and inserts  53  around the stationary lower support assembly  65  (and away from the corresponding wheelchair  39 ), simply pull the retractable, spring-loaded plunger  76  from the lower support assembly  65 ; doing so will disengage the tip  78  of the spring-loaded plunger  76  from the slot  71  found on the short vertical tube  68 , which will allow the upper support assembly  64  and Eco-Tray assembly with brackets and inserts  53  to freely rotate.  
         [0340]     For aesthetic purposes, an endcap (not shown) may be inserted into the bottom end of the short vertical tube  68  or the distal end of the horizontal tube  69 .  
         [0341]     4) The standard inner mounting clamp  66 , of standard construction, depicted in  FIGS. 19, 22  and  23 , preferably made of metal or aluminum, is comprised of: 
        top clamp section  80      center clamp section  81      bottom clamp section  82      fasteners  83         
 
         [0346]     The circular recesses  84  (can be square or rectangular, not shown, depending on the wheelchair frame  85  type) from the center clamp section  81  and bottom clamp section  82  of the standard inner mounting clamp  66  are positioned on either side of the wheelchair frame  85  and secured with fasteners  83 . (See  FIG. 23  for assembled standard inner mounting clamp  66 .)  
         [0347]     5) The short clamping tube  67 , depicted in  FIGS. 19, 22  and  23  is preferably made of metal, aluminum, fiberglass or plastic, and is of square, rectangular or circular shape (depicted). The short clamping tube  67  attaches into the circular recesses  84  from the top clamp section  80  and the center clamp section  81  of the standard inner mounting clamp  66 . Once the fasteners  83  are secured through clearance holes  98  in the top clamp section  80  and into threaded holes  86  in the center clamp section  81 , the short clamping tube  67  is secured in place to the standard inner mounting clamp  66 .  
         [0348]     6) The standard outer mounting clamp  79 , of standard construction, depicted in  FIGS. 19 and 23 , preferably made of metal or aluminum, is of the same design as the standard inner mounting clamp  66 , and is comprised of: 
        top clamp section  87      center clamp section  88      bottom clamp section  89      fasteners  90         
 
         [0353]     The circular recesses  91  (can be square or rectangular, not shown, depending on the wheelchair frame  85  type) from the bottom clamp section  89  and center clamp section  88  of the standard outer mounting clamp  79  are positioned around the bent tube  75  from the lower support assembly  65 . Once the fasteners  90  are secured through clearance holes  93  in the bottom clamp section  89  and into threaded holes  94  in the center clamp section  88 , the bent tube  75  (and corresponding lower support assembly  65 ) is secured to the standard outer mounting clamp  79 .  
         [0354]     The Eco-Tray assembly with brackets and inserts  53 , upper support assembly  64 , lower support assembly  65 , standard inner mounting clamp  66 , standard outer mounting clamp  79 , and short clamping tube  67  described above can be retrofit by a customer to a wheelchair  39  without drilling or welding. The customer can receive these six components  53 ,  64 ,  65 ,  66 ,  67  and  79  individually-wrapped. The customer&#39;s first step would be to secure the standard inner mounting clamp  66  onto the wheelchair frame  85 . The second step would be to secure the short clamping tube  67  into the standard inner mounting clamp  66 . The third step would be to secure the standard outer mounting clamp  79  onto the short clamping tube  67 . The fourth step would be to install the bent tube  75  from the lower support assembly  65  into the standard outer mounting clamp  79 . Somewhere away from the wheelchair, the Eco-Tray assembly with brackets and inserts  53  would be assembled onto the upper support assembly  64 . The final assembly step would be to install the short vertical tube  68  from the upper support assembly  64  (which is already attached to the Eco-Tray assembly with brackets and inserts  53 ) into the lower support assembly  65 . Height adjustments of the Eco-Tray assembly with brackets and inserts  53  can be made two ways: 1) the set screw  74  from the tube collar  96  is loosened, which allows the tube collar  70  to be re-positioned up or down along the short vertical tube  68  from the upper support assembly  64  or 2) the fasteners  90  from the standard outer mounting clamp  79  are loosened, which allows the bent tube  75  from the lower support assembly  65  to be re-positioned up or down within the standard outer mounting clamp  79 .  
         [0355]     Novel uses of the fold away Eco-Tray mounting means embodiment  52  are depicted in FIGS.  25  to  29 . If the wheelchair occupant desires to move the Eco-Tray assembly with brackets and inserts  53  away from the front of the wheelchair  39 , the occupant simply pulls a handle on the retractable, spring-loaded plunger  76  and rotates the Eco-Tray assembly with brackets and inserts  53  and attached upper support assembly  64  away from the wheelchair  39 .  FIGS. 26 and 27  depict the Eco-Tray assembly with brackets and inserts  53  and upper support assembly  64  rotated 180 degrees (relative to the position shown in  FIG. 19 ).  FIGS. 28 and 29  depict the Eco-Tray assembly with brackets and inserts  53  and upper support assembly  64  rotated nearly 270 degrees (relative to the position shown in  FIG. 25 ) with the Eco-Tray assembly with brackets and inserts  53  oriented nearly vertical. In the 270-degree orientation, the outermost left edge  62  of the Eco-Tray assembly with brackets and inserts  53  only extends approximately 2 inches (50.8 centimeters) beyond the left wheel  63  of the wheelchair  39 . The distance from the outermost left edge  62  of the Eco-Tray assembly with brackets and inserts  53  to the outermost edge of the right wheel  99  of a typical 26 inch (660.4 centimeter) wide wheelchair would therefore be approximately 28 inches (711.2 centimeters)—as depicted in  FIG. 29 .  
         [0356]     The two orientations (180-degree and 270-degree) of the Eco-Tray assembly with brackets and inserts  53  and the upper support assembly  64  discussed above are practical for: 1) a caretaker/nurse who wishes to perform a “lateral transfer” or “pivot transfer” of a patient into or out of the wheelchair or 2) the wheelchair occupant to enter and exit the wheelchair using his/her own strength. In addition, the latter, compact, 270-degree orientation provides a very practical use for a wheelchair occupant who must travel from one room to another room in a home: the wheelchair  39  with attached fold away Eco-Tray mounting means embodiment  52  measures only approximately 28 inches (711.2 centimeters), thus allowing the wheelchair  39  with attached fold away Eco-Tray mounting means embodiment  52  to pass through a standard 29 inch (736.6 centimeter) wide door frame opening.  
       Description of Alternative Internal Connecting Support Rib Orientation Embodiments  
       [0357]     The connecting support ribs  6  of the multi-wall tray  2  shown in  FIG. 3  and the connecting support ribs  46  of the multi-wall rectangular tray  43  shown in  FIG. 15  are oriented in the preferred direction parallel to the length of the left and right wheelchair armrests  15 ,  16  when in use by the wheelchair occupant. Note that the connecting support ribs  6 ,  46  can also be oriented perpendicular to the length of the wheelchair armrests  15 ,  16  or at any other angle (not shown). The spacing between the ribs  6 , dimension J from  FIG. 3 , can also be modified to allow for a smaller or larger hollow opening  14 .  
         [0358]     The preferred orientation of the connecting support ribs  6 ,  46  parallel to the length of the left and right wheelchair armrests  15 ,  16 , as depicted in  FIG. 3 , is completely intentional. When the multi-wall tray  2  is secured to the top of the wheelchair armrests  15 ,  16  the distal end  51  of the multi-wall tray  2  opposite the left and right arm extensions  8 , 9  extends out beyond armrests  15 ,  16 . This overhanging distal end  51  of the multi-wall tray  2  is a scenario known in mechanical engineering terms as a “cantilevered beam”.  
         [0359]     The preferred orientation of the connecting support ribs  6 ,  46  is engineered to provide multi-wall trays  2 ,  43  that are able to support heavy objects placed onto the top panels  4 ,  44  without bending the top panels  4 ,  44  or bottom panels  5 ,  45  of the multi-wall trays  2 ,  43 . The intended orientation of the connecting support ribs  6 ,  46  provides a similar support mechanism as found in a typical transportation vehicle bridge. In such a bridge, the cross-section of the structural concrete or metal is typically manufactured in an “I” shape and the concrete beams or metal beams lay parallel to the length of the bridge. The multi-wall trays  2 ,  43  are also manufactured with individual I-shaped cross-sections  109  due to geometry created by the support ribs  6 ,  46  and corresponding panels  4 ,  44 ,  5 ,  45 , as shown in  FIG. 31 . As with the bridge structure, the I-shaped cross-sections  109  ensure that the multi-wall trays  2 ,  43  remain rigid when a heavy item is placed on the top panels  4 ,  44  of the multi-wall trays  2 ,  43 .  
       Description of Alternative Multi-Wall Tray Design Embodiments  
       [0360]     The multi-wall trays  2 ,  43  have been described as having top panels  4 ,  44  and bottom panels  5 ,  45  with connecting support ribs  6 ,  46 , as depicted in  FIG. 31 . However, the multi-wall trays  2 ,  43  can be also manufactured with additional support panels  110  beyond the top and bottom panels  4 ,  44 ,  5 ,  45  described, as depicted in  FIGS. 30 and 32 . These additional panels  110  would provide additional structural support. Also, the connecting support ribs  6 ,  46  were previously depicted in a generally vertical orientation. However, the connecting support ribs  6 ,  46  can be oriented at alternate rib angles  111  other than vertical.  FIGS. 30 and 32  depict alternate multi-wall configurations  175  which can also be utilized for a wheelchair tray.  
       Description of Alternative Edge Trim Molding Embodiments  
       [0361]     Many different edge trim molding shapes and styles can be assembled along the perimeters  10 ,  49  of the multi-wall trays  2 ,  43 .  FIG. 34  depicts various alternative shapes and styles of edge trim moldings  176  that can be utilized: U-shaped, flat and L-shaped. The top item in  FIG. 35  depicts the preferred C-shaped edge trim molding  3  utilized in this document, while the bottom item in  FIG. 35  depicts the C-shaped edge trim molding  3  with a raised flexible rim  177  adhered at the side. The edge trim moldings  3 ,  176  can be made of plastic, rubber, or other material which is easy to bend, cut and/or assemble. The edge trim moldings  3 ,  176  can be attached with any known prior art adhesives (e.g. cyanoacrylates, epoxies, TV-cured adhesives, double-sided tape, etc.). These various trim shapes and styles can a) keep wheelchair occupants from sticking fingers inside the openings  14 ,  47  of the multi-wall trays  2 ,  43 , b) keep the openings  14 ,  47  of the multi-wall trays  2 ,  43  free from contaminants, c) provide a raised edge to keep items such as pencils from falling off the multi-wall trays  2 ,  43  during normal use, or d) provide a smooth edge around the perimeter  10 ,  49  of the multi-wall trays  2 ,  43  for general safety of the wheelchair tray user.  
       Description of Cup Holder Embodiment  
       [0362]     A circular hole  112  can be cutout into the top surface of the multi-wall trays  2 ,  43  as depicted in  FIGS. 36 and 37 . This circular hole  112  can be used for receiving a cup  113  or other container which contains a beverage. The circular hole  112  passes thru the top panel  4 ,  44  and the connecting support ribs  6 ,  46  but does not proceed completely thru the entire thickness of the multi-wall tray  2 ,  43 , leaving the bottom panel  5 ,  45  in tact.  
         [0363]     As seen in  FIG. 37 , the remaining bottom panel  5 ,  45  of the multi-wall tray  2 ,  43  supports the underside of a cup  113  and the connecting support ribs  6 ,  46  provide support at the sides. To prevent liquids or other contaminants from entering the hollow openings  14 ,  47  in the multi-wall trays  2 ,  43  the circular hole  112  can be filled along its perimeter with edge trim molding  3  or any filler material (not shown).  
       Description of Folding Tray Embodiment  
       [0364]     The width of the multi-wall tray  2 ,  43  can be decreased by half of its original size for easy storage by allowing the tray  2 ,  43  to fold at the center, as depicted in  FIGS. 33, 38  and  39 .  
         [0365]     The folding tray embodiment  114  is comprised of three main elements:  
         [0366]     1) left tray half  115   
         [0367]     2) hinge  116   
         [0368]     3) right tray half  117   
         [0369]     The left tray half  115  and right tray half  117  are made of the same material used in the multi-wall tray  2  and each is essentially a full multi-wall tray  2  cut in half.  
         [0370]     The hinge  116  shown in  FIGS. 33 and 39  can be manufactured from plastic or metal. The hinge  116  is comprised of a hinge pin  166 , left hinge section  167  and right hinge section  168 . The mounting flat  171  of the left hinge section  167  is secured to the edge of the left tray half  115  with a conventional adhesive, while the mounting flat  172  of the right hinge section  168  is secured to the edge of the right tray half  117  in the same fashion. The left hinge section  167  and right hinge section  168  are aligned such that the holes in the left hinge knuckle  169  and holes in the right hinge knuckle  170  are concentric. The hinge pin  166  is then installed thru the holes in the left hinge knuckle  169  and the holes in the right hinge knuckle  170 . Finger pinch points are eliminated due to the design of the hinge  116 , which contains radiused edges  118  that push the user&#39;s fingers away from the hinge  116  when folding the two tray halves  115 ,  117  together.  FIG. 39  shows the two halves  115 ,  117  of the tray folded over.  
         [0371]     In the open position during normal intended use, as depicted in  FIG. 38 , the tray halves  115 ,  117  are unfolded parallel and collinear to one another. When not in use in the closed position, as depicted in  FIG. 39 , the two halves are folded about the hinge  116  which acts as pivot point. The folding tray embodiment  114  stays closed when weight is applied to the top surface of the tray and cannot accidentally unfold. The folding tray embodiment  114  can be installed onto the armrests  15 ,  16  of the wheelchair  39  with any of the previous mounting means presented.  
       Description of Printed Advertisement Embodiments  
       [0372]     Paper, plastic or any other printable material  120  can be placed inside the openings  14  of the multi-wall tray  2  to produce the Ad-Tray embodiment  119 . See  FIGS. 40 and 41 . The printed side of the printable material  120  can be adhered to the inside of the top panel  4  of the multi-wall tray  2  with liquid adhesive, double-side tape or pressure-sensitive adhesive (a.k.a. PSA) found on the printable substrate. Alternately, the printable material  120  can be a removable electrostatic substrate. The printable material  120  can be removed and replaced via an opening  14  or hinged door (not shown) found along the outer perimeter  10  of the multi-wall tray  2 . The use of these printable materials  120  can be for advertising or playing games (such as checkers) on the top panel  4  of the multi-wall tray  2 . The printed materials can also be printed, for example, to suggest the various wheelchairs styles and models that the multi-wall wheelchair tray is compatible with.  
       Description of Functional Entertainment Embodiments  
       [0373]     Pens, pencils or gaming devices such as dice, game pieces or dominoes (not shown) can also be installed into the openings of the multi-wall tray  2 . Alternately, these items can be installed into a small box (not shown), which would assemble into the openings  14  of the multi-wall tray  2 . When not in use, a hinged door (not shown) can be utilized to keep these components from falling out of the multi-wall tray  2 .  
       Description of Carrying Handle Embodiment  
       [0374]     A handle  122  can be installed along the perimeter  10  of the I-tray embodiment  1  for easy carrying of the tray  1 ,  2 , as depicted in  FIGS. 42 and 43 . The preferred embodiment entails securing the handle  122  into holes  123  in the edge trim molding  3 . If an edge trim molding  3  is not used, then the handle  122  can be installed directly into a hole (not shown) in one of the connector support ribs  6  of the multi-wall tray  2 . Alternatively, the handle  122  can also be attached to the edge trim molding  3  or connector support ribs  6  with any known prior art heat staking process or adhesive (e.g. cyanoacrylates, epoxies, UV-cured adhesives, double-sided tape, etc.).  
       Description of Electronics Docking Station Embodiment  
       [0375]     The previously depicted I-Tray embodiment  1  is modified to create a new design known as the electronics docking station embodiment  125 , depicted in FIGS.  44  thru  46 . The existing hollow openings  14 ,  47  in the multi-wall trays  2 ,  43  can be used to house electronic devices such as an MP3 player, cell phone, AM/FM radio, satellite radio receiver, DVD player, radio-frequency identification (a.k.a. RFID) device, etc. The electronics docking station embodiment  125  is depicted in  FIG. 44  with an Apple iPod® Shuffle™  126  awaiting installation.  
         [0376]      FIG. 45  depicts the electronics docking station embodiment  125  with the top panel  132  of the electronics docking multi-wall tray  127  removed for clarity. A small support rib  128  with circular hole  129  is permanently installed between and perpendicular to the opening  14  in the electronics docking multi-wall tray  127  with any conventional adhesive. The small support rib  128  serves two purposes: a) prevent the iPod® Shuffle™  126  or any other electronic device from sliding or falling into the center of the electronics docking multi-wall tray  127  and b) provide a circular mounting hole  129  for the attachment of a component such as a stereo male plug  130 .  
         [0377]     The iPod® Shuffle™  126  is shown installed into the opening  136  at the wheelchair user side  137  of the electronics docking multi-wall tray  127  in  FIG. 45  with approximately 12 inch of the iPod® Shuffle™  126  protruding from the front of the opening  136 . The female jack from an Apple iPod® Shuffle™  126  is connected to the stereo male plug  130 , which is secured to the small support rib  128  inside the electronics docking multi-wall tray  127 . The stereo male plug  130  is shown attached to two wires  135  which are located inside the openings  136  of the electronics docking multi-wall tray  127 . The opposite end of the wires  135  are connected to water-resistant speakers  134 . The wires  135  are held in place between the far side perimeter edge  138  of the electronics docking multi-wall tray  127  and the edge trim molding  3 . An optional wire recess groove  139  is shown along the far side perimeter edge  138  of the electronics docking multi-wall tray  127 . The speakers  134  can be secured to the bottom panel  133  of the electronics docking multi-wall tray  127  with an industrial-grade adhesive.  
         [0378]     An optional circular cutout  131  is shown in the top panel  132  of the electronics docking multi-wall tray  127 . Any combination of round, square or rectangular cutouts can be located along the top panel  132 , bottom panel  133  or edge trim molding  3  of the electronics docking multi-wall tray  127  to allow access to volume, channel, on/off buttons or a headphone jack from any electronics device.  
         [0379]     When an electronic device such as the iPod® Shuffle™  126  is installed into the opening  136  in the electronics docking multi-wall tray  127  and pushed forward, the electronic device becomes mated with the stereo male plug  130 . The electronic signal from the electronic device is transmitted from the male plug  130 , through the wires  135  and into the speakers  134 . This allows the electronics docking station embodiment  125  to be used as an amplification means for an installed electronic device. Alternatively, a microphone (not shown) can be used in place of one speaker  134 —this would allow the electronics docking station embodiment  125  to be used as a recording device as well as an amplification means.  
       Description of Solar Panel Charging System Embodiment  
       [0380]     Solar panel arrays  141  are typically wafer-thin rigid or flexible elements that contain individual photovoltaic cells which convert photonic energy to electrical energy. Solar panel arrays  141  can be housed inside the openings  142  of the solar panel multi-wall tray  143  to form the solar panel charging system embodiment  140  shown in FIGS.  47  thru  49  and  52 . Any electronic device installed inside of or external to the solar panel multi-wall panel tray  143  can be powered and/or recharged by photonic energy from the sun or any other lighting means. In this embodiment  140 , it is preferred that the plastic material used for the solar panel multi-wall tray  143  be translucent or transparent in order for light to reach the solar panel arrays  141  stored inside of the tray  143 .  
         [0381]     Solar panel arrays  141  are connected to a battery pack  144  or capacitors (not shown) found inside the solar panel multi-wall panel tray  143  to store the converted electrical energy. A user&#39;s external electronic device, such as the cellular phone with charging cable  146  shown in  FIG. 48 , can be plugged into the charging port  145  located along the outer perimeter of the solar panel multi-wall tray  143 . The charging port  145  depicted in these drawings is the ubiquitous female Universal Serial Bus (a.k.a. USB) connector.  
         [0382]      FIGS. 47 &amp; 49  depict two solar panel arrays  141 , a battery pack  144 , two voltage regulators  147 ,  151  and cables  148  installed inside the solar panel multi-wall tray  143 . It would be preferred that each solar panel array  141  contain at least thirty (30) photovoltaic cells, so that charging can occur even under standard office lighting conditions. Each cable  148  contains two twenty-two (22) gage wires for proper transmission of the electricity. See  FIG. 52  for a block diagram of the flow of electricity through the components in the solar panel charging system embodiment  140 .  
         [0383]     Thirty (30) photovoltaic cells are installed in series on each solar panel array  141 . Each cell provides 0.5 Volts @ 450 mA. Therefore, the solar panel array with thirty cells in series provides 15 Volts at 450 mA when used under optimal lighting conditions.  
         [0384]     In this solar panel charging system embodiment  140 , it is preferred that the battery pack  144  contains a plastic housing and internal wiring to accommodate six (6) recharge-able AAA (a.k.a. triple A) batteries. The batteries can also be Nickel-Metal-Hydride (NIMH), Lithium-Ion (Li-Ion), Nickel-Cadmium (NiCd), alkalyd, or alkaline. Each non-alkaline, re-chargeable AAA battery provides 1.2 Volts (alkaline provides 1.5V). Stacking six (6) re-chargeable AAA batteries in series in the battery pack  144  provides 7.2 Volts of power with 650 milli-amp hours of storage. This is advantageous because most Direct Current (DC) electronic components (e.g. integrated circuits, cell phones, MP3 players, etc.) run at 5 Volts.  
         [0385]     Two voltage regulators  147 ,  151  are utilized in the embodiment to limit the risk of overcharging the internal battery pack  144  or any external electronic device plugged into the charging port  145 . The first voltage regulator  147  is connected between the solar panel arrays  141  and battery pack  144  and limits the power delivered from the solar panel arrays  141  to the battery pack  144 . The second voltage regulator  151  is connected between the battery pack  144  and the charging port  145  and controls the amount of power delivered from the battery pack  144  to the charging port  145 . A current limiting resistor limits the current. Output from the USB interface standard is 5 Volts at 500 mA of output.  
         [0386]     The battery pack  144 , voltage regulators  147 ,  151 , cables  148  and the solar panel arrays  141  are slid into the openings  142  in the solar panel multi-wall tray  143  and secured with a pressure-sensitive adhesive (i.e. PSA) or any other conventional adhesive means. See  FIG. 49  with the top panel  158  removed from clarity.  
         [0387]     The cables  148  between the solar panel arrays  141  and voltage regulators  147  are held in place between the far side perimeter edge  138  of the solar panel multi-wall tray  143  and the edge trim molding  3 . An optional wire recess groove  149  is also shown along the far side perimeter edge of the solar panel multi-wall tray.  
       Description of Electronic Display Embodiment  
       [0388]     The multi-wall tray  2 ,  43  can be used to store and protect an electronic display  157  in a configuration known as the electronic display embodiment  153 , which is depicted in  FIGS. 50 and 51 . The electronic display  157  can be a fully-functional independent device such as a Tablet PC or a dependent remote display such as the Sony LocationFree™ TV.  
         [0389]     In the electronic display embodiment  153 , the electronic display multi-wall tray  154  has a generally rectangular cutout  155  located across the bottom panel  156 , whereby several ribs and a portion of the bottom panel  156  are removed. See  FIG. 51  with edge trim molding  3  removed for clarity. The electronic display  157  is installed into the rectangular cutout  155  from the rear of the electronic display multi-wall tray  154 . In this orientation, the electronic display screen  159  faces towards the back side of the top panel  158  from the electronic display multi-wall tray  154 . Let it be known that the wheelchair user would view the screen  159  of the electronic display  157  from the vantage point  178  depicted in  FIG. 50 .  
         [0390]     A transparent or translucent material is preferred for the electronic display multi-wall tray  154 , so that one can see through the top panel  158  of the tray  154  to view the electronic display screen  159 . The electronic display  157  is held in place inside the rear rectangular cutout  155  of the tray  154  with a mounting plate  160 . See  FIG. 51 . The mounting plate  160  can be secured to the bottom panel  156  of the tray  154  with fasteners  161  which install through holes  162  in the mounting plate  160 . Alternate mounting means for the plate  160  are also possible, such as double-sided adhesive tape, Velcro® or any other prior art means. Aluminum material is the preferred material for the mounting plate  160  due to aluminum&#39;s good thermal transfer properties which can keep the installed electronic display  157  cool—however, the mounting plate  160  can be made with other material types besides aluminum.  
         [0391]     The top panel  158  of the tray  154  (the rear side of which is shown in  FIG. 51 ) and the mounting plate  160  protect the electronic display  157  from mechanical damage on either side. An optional rubber gasket  163  can be installed between the electronic display  157  and mounting plate  160  to prevent spilled liquids from contacting and possibly damaging the electronics. Solid-state electronics (i.e. flash-ROM) or a hard-drive can also be installed into the multi-wall tray  154  utilizing similar mounting and protection means.  
         [0392]     Lastly, an optional USB port with cable  164  can be installed at the perimeter of the electronic display embodiment  153  via a hole  165  which extends through the multi-wall tray  158  and edge trim molding  3 . Note that the electronic display  157  would need to contain an accessible USB port  174  to be used with the optional USB port with cable  164 . The USB port with cable  164  can be secured to either the edge trim molding  3  or to the multi-wall tray  158  with traditional adhesives, since a USB port can be procured with an outer protective housing manufactured from plastic. The connector  173  from the USB port with cable  164  is mated into the USB port  174  from the electronic display  157  before final assembly of the electronic display  157  to the multi-wall tray  154 . An external device such as a keyboard can be plugged into the optional USB port with cable  164 , allowing the external device to communicate with the electronic display  157 .  
       Modular Multi-Wall Tray Retrofitable to a Wheelchair Conclusion  
       [0393]     The novel design embodiments disclosed in this document address many of the disadvantages associated with the use of traditional wheelchair trays.  
         [0394]     A traditional solid wheelchair tray can pose a safety hazard if accidentally dropped onto a person&#39;s extremities and can also be difficult for a wheelchair occupant to lift due to the inherent weight of the material. The traditional wheelchair tray can also flex during usage with an electronic device such as a portable computer, which can allow the electronics to fall from a bent tray. The wheelchair tray design presented is at least 100% lighter than traditional solid wheelchair trays of similar overall thickness, but more than twice as rigid. This is due to the cross-sectional design of the multi-wall panel, which has been engineered to withstand substantial weight at a given thickness.  
         [0395]     The wheelchair tray presented does not require separate support means such as an exterior aluminum rim along tray&#39;s outer perimeter or additional support brackets to buttress its cantilevered end. In addition, the reduced weight of the proposed wheelchair tray can reduce the harming of individuals if the wheelchair tray were to be dropped onto a person&#39;s extremities. This can provide safer living conditions for the wheelchair occupant and safer working conditions for care-takers, physical therapists, nurses, doctors or other rehabilitation personnel.  
         [0396]     Existing wheelchair trays have a limited capacity in securing and protecting electronics, since the electronics are usually simply placed along the top surface of the tray. Currently, due to the traditional manufactured construction of a solid sheet of material, a typical wheelchair tray does not include any provision for internally housing electronic devices which may benefit the user. Cell phones, computers, PDA&#39;s, music playing devices, lighting systems and their associated power sources such as batteries, solar cells/panels or inductive charging systems must be used as external accessories. These electronics are typically placed on the top surface of a solid tray and are not protected from foreign contaminants which may damage the electronic equipment.  
         [0397]     Electronics can be installed into the openings of the engineered multi-wall wheelchair tray to create many electronic embodiments not previously available to the wheelchair tray user. In addition, the wheelchair tray embodiments with adhered trim molding can keep valuable internal electronics safe and also provide an IP21 level of water and dust ingress protection per IEC 60529.  
         [0398]     The design depicted in this document is specifically geared to be retrofitable to most manufactured wheelchairs (manual or electric), but one skilled in the art can modify this design to work in other applications as well. For example, the fold away Eco-Tray mounting means embodiment  52  can be retrofit onto a bed frame (for hospital or home usage), onto a table (for restaurant usage, etc.) or onto a seat (for usage at an airport bus terminal, etc.).  
         [0399]     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.  
         [0400]     For example, although specific means of mounting the multi-wall tray have been disclosed, many other means of attaching the tray to a wheelchair or other object are possible. These other mounting means may be broken down into two categories: 1) passive and 2) active. The passive mounting means may include 1a) magnets stored inside the openings of the multi-wall tray that attach to conductive brackets located around the wheelchair armrests or frame, 1b) suction cups that attach to the wheelchair armrests, frame or separate bracket installed on the wheelchair, 1c) brackets or tubes that extend from inside the openings of the multi-wall tray or secure to the bottom panel of the multi-wall tray and mount to the axle of a wheelchair wheel, 1d) brackets or tubes that extend from inside the openings of the multi-wall tray or secure to the bottom panel of the multi-wall tray and mount to a bracket or tube secured to a wheelchair frame or armrest, 1e) a hinge that extends from inside the openings of the multi-wall tray or secures to the bottom panel of the multi-wall tray and mounts to a wheelchair frame, armrest or bracket installed onto the wheelchair, or 1f) an upper support assembly  64  as described earlier with a longer vertical tube  68  that mounts directly into a mounting tube secured to the wheelchair footrest (reference U.S. patent application Ser. No. 11/200,838, filed Aug. 10, 2005 for details of a mounting tube means configured to mount to the footrest of a wheelchair). The active mounting means possible to secure the multi-wall tray to a wheelchair may include 2a) conductive fasteners secured to both the multi-wall tray and wheelchair that are electrically coupled and activated with an external power means or 2b) an electronically-activated solenoid, linear actuator, rotary actuator or servomotor, a mechanical spring, a pneumatic or hydraulic strut secured inside the openings of the wheelchair tray or secured to the bottom panel of the multi-wall tray that engages into a corresponding mating feature on the wheelchair frame, armrest or separate bracket installed onto the wheelchair. Any of the passive mounting means may also be combined with an active mounting means to secure the multi-wall tray to a wheelchair.  
         [0401]     In addition, while many of the components are described as being plastic, it is possible to provide that the components are instead made of carbon fiber. Note that the I-Tray embodiment  1  and Eco-Tray  42  embodiment are depicted with edge trim molding  3 ; however, these embodiments can also be manufactured without the use of edge trim molding  3 . Also, the Eco-Tray embodiment  42  depicted in the fold away EcoTray mounting means  52  can be replaced with the I-Tray embodiment  1 . Many other variations are fully possible while staying within the scope of the present invention.