Patent Publication Number: US-7900566-B1

Title: Portable chair tray

Description:
BACKGROUND 
     1. Field 
     The information disclosed in this patent relates to a tray that may be attached to a portable chair. 
     2. Background Information 
     Portable chairs provide sitting convenience in a variety of situations. For example, electricians typically bring portable chairs to job sites to have a place to sit while eating lunch. However, most electricians use buckets or boxes to place their food on while eating. 
     Others use portable chairs in a variety of settings but often lack a stable, flat surface from which to eat or work. For example, homeowners, campers, anglers, and outdoor sporting event spectators utilize portable chairs but typically use a makeshift item to support their equipment or food. Handicap people confined to wheelchairs often have immediate needs for a tray that may function as an eating, writing, drawing, or studying table or platform, but lack the ability to find any makeshift item to serve that purpose. Thus, there is a need for a stable, flat surface that may be attached to a portable chair. 
     SUMMARY 
     Disclosed is a tray for a portable chair. The tray may include a table attached to a support rod by a first linkage and a second linkage. The first linkage may include a first linkage slot. The tray further may include a clamp attached to the support rod. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is an isometric view of a tray  100 . 
         FIG. 2  is an enlarged, isometric partial view of tray  100 . 
         FIG. 3  is an exploded isometric partial view of tray  100 . 
         FIG. 4  is rear view of tray  100 . 
         FIG. 5  is a right side view of tray  100 . 
         FIG. 6  is a top partial view of tray  100 . 
         FIG. 7  is a top partial view of tray  100  with clamp  110  attached to chair upright portion  14 . 
         FIG. 8  is an isometric view of a tray  800  attached to chair  10 . 
         FIG. 9  is a side view of tray  800 . 
         FIG. 10  is a section view of table  806  generally taken off line  10 - 10  of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is an isometric view of a tray  100 . Tray  100  may provide a flat work surface for those sitting in a chair  10  having a chair opening  12 . Chair  10  may be a portable chair, such as a folding chair, a lawn chair, and a wheelchair. Through an assembly of part, tray  100  may be attached to a chair upright portion  14  of chair  10  and manipulated into various positions to assist in sitting activities, such as eating, writing, drawing, and studying. Tray  100  may be rotated away from chair opening  12  to permit a person to sit and leave chair  10 . Tray  100  may be removed from chair  10  and collapsed into a low profile that takes up minimal storage and transportation space. 
       FIG. 2  is an enlarged, isometric partial view of tray  100 . Tray  100  may include a support rod  102 , a first linkage  104 , a second linkage  106 , a table  108 , and a clamp  110 . First linkage  104  and second linkage  106  may be attached between table  108  and support rod  106 . Support rod  106  may be attached to clamp  110  to form tray  100 . Clamp  110  may be utilized to attach tray  100  to chair upright portion  14  of chair  10 . 
       FIG. 3  is an exploded isometric partial view of tray  100 . Support rod  102  may be an elongated hollow tube having a first cap  112 , a second cap  114 , an offset  116 , a first threaded hole  118 , and a second threaded hole  120 . Support rod  102  may be defined approximate measurements, including a support rod length  122  as measured between first cap  112  and second cap  114 , a support rod diameter  124 , an offset length  126  as measured from first cap  112  an offset width  128 , and an offset clearance  130 . 
     First cap  112  and second cap  114  may be covers that may enclose a hollow interior  132  of support rod  102 . If hollow interior  132  were left open, children might hurt their fingers by inserting them into hollow interior  132 . First cap  112  and second cap  114  work to prevent harm to children and others who might stick their fingers in hollow interior  132 . 
     Offset  116  may be a bend formed into support rod  102  within a horizontal plane  134  passing through a first support rod centerline  136  and a second support rod centerline  138 . This bend assists in centering table  108  on chair opening  12  ( FIG. 1 ). In addition, offset  116  may provide an open gap  140  ( FIG. 1 ) between chair upright portion  14  of chair  10  and an edge of table  108  to reduce a feeling of being trapped within chair  10 . 
     In one example, support rod length  122  approximately may be sixteen inches, support rod diameter approximately may be ½ to one inch, offset length  126  approximately may be three to five inches, support rod diameter  124  may be ¼ inch to one inch, preferably ½ inch, offset width  128  as measured from second support rod centerline  138  to first support rod centerline  136  approximately may be three inches, and offset clearance  130  as measured from first cap  112  along second support rod centerline  138  approximately may be one to four inches. In another example, a ratio of support rod length  122  to offset length  126  may be 4:1. When table  108  is positioned parallel to support rod  102 , table  108  may be parallel to offset  116 . 
     First threaded hole  118  and second threaded hole  120  may be internally threaded openings within support rod  102  configured to receive an externally threaded bolt. Alternatively, first threaded hole  118  and second threaded hole  120  each may receive a grommet that includes an extended internally threaded interior. In one example, support rod  102  contains no holes other than first threaded hole  118 , second threaded hole  120 , and those openings closed by first cap  112  and second cap  114 . 
     First linkage  104  and second linkage  106  may permit a user to raise and lower table  108  relative to their lap, move table  108  closer to and away from their torso, and tilt table  108  at an angle relative to horizontal plane  134  ( FIG. 3 ), or adjust table  108  to be horizontal. 
     First linkage  104  may include first linkage bottom  142 , a first linkage top  144 , a first linkage front side  146 , a first linkage back side  148 , a first linkage length  150 , a first linkage slot  152  extending from first linkage bottom  142  along more than ¾ of first linkage length  150 , a first linkage through hole  153 , and first linkage cams  154  interleaved with first linkage grooves  156 . Second linkage  106  may include second linkage bottom  158 , a second linkage top  160 , a second linkage front side  162 , a second linkage back side  164 , a second linkage length  166 , a second linkage slot  168  extending from second linkage bottom  158  along more than ¾ of second linkage length  166 , a second linkage through hole  170 , and second linkage cams  172  interleaved with second linkage grooves  174 . First linkage  104  and second linkage  106  may have similar constructions. For example, each approximately may be ¼-inch thick. 
     In one example, first linkage length  150  approximately may be seven to ten inches and first linkage slot  152  approximately ma be ¼-inch wide. First linkage cams  154  and first linkage grooves  156  both may extend away from first linkage front side  146 , but first linkage cams  154  may extend further away from first linkage front side  146  than first linkage grooves  156  to create projections. First linkage cams  154  and first linkage grooves  156  may radiate outward from first linkage through hole  153  to a first linkage perimeter  176  to form wedge projections and wedge indentations. 
     Table  108  may be a platform having a table top  178  and a table underside  180 . Both table top  178  and table underside  180  may be smooth and flat. Attached to table underside  180  may be a first bracket  182  having a first bracket threaded hole  183  and first bracket cams  184  interleaved with first bracket grooves  186  and a second bracket  188  having a second bracket threaded hole  189  and second bracket cams  190  interleaved with second bracket grooves  192 . First bracket  182  and second bracket  188  may be L-shaped and may have similar construction. Both brackets may extend far enough away from table underside  180  to receive linkages  104 ,  106  and permit them to rotate. 
     Tray  100  may include a first knob  194 , a second knob  196 , a third knob  198 , a fourth knob  200 , and a fifth knob  202 . Knobs  194 ,  196 ,  198 , and  200  may include a head with one side of the head having radial teeth and a threaded bolt extending from that side having radial teeth. The radial teeth may grip and seat a mating surface. 
     First linkage  104  and first bracket  182  may be secured together by inserting first knob  194  through first linkage through hole  153  and screwing first knob  194  into first bracket threaded hole  183 . Second linkage  106  and second bracket  188  similarly may be secured together by second knob  196 . First linkage cams  154  may be configured to mate with first bracket grooves  186  and first linkage grooves  156  may be configured to mate with first bracket cams  184  such that, when compressed together by the tightening action of first knob  194 , first linkage  104  and first bracket  182  may be prevented from rotating relative to each other. Along with a similar interaction between second linkage  106  and second bracket  188 , this may prevent table  108  from moving away from or closer to the user. 
       FIG. 4  is rear view of tray  100 . As illustrated, second linkage cams  172  mate with second bracket grooves  192  and second linkage grooves  174  may be configured to mate with second bracket cams  190  such that, when compressed together by the tightening action of second knob  196 , second linkage  106  and second bracket  188  may be prevented from rotating relative to each other. 
       FIG. 5  is a right side view of tray  100 . First linkage  104  may be attached to support rod  102  by passing third knob  198  through first linkage slot  152  and screwing third knob  198  into first threaded hole  118  ( FIG. 3 ). Second linkage  106  may be attached to support rod  102  by passing fourth knob  200  through second linkage slot  168  and screwing fourth knob  200  into second threaded hole  132  ( FIG. 3 ). 
     As noted above, first linkage  104  and second linkage  106  may permit a user to raise and lower table  108  relative to their lap, move table  108  closer to and away from their torso, and tilt table  108  at an angle relative to horizontal plane  134  ( FIG. 3 ) or adjust table  108  to be horizontal. Each of these may be accomplished by loosening different combinations of first knob  194 , second knob  196 , third knob  198 , and fourth knob  200 , raising, rotating, and/or angling table  108 , then tightening first knob  194 , second knob  196 , third knob  198 , and fourth knob  200  to secure table  108  in position. When table  108  is positioned parallel to support rod  102 , table  108  may be parallel to offset  116 . 
       FIG. 6  is a top partial view of tray  100 . As noted above, clamp  110  may be utilized to attach tray  100  to chair upright portion  14  of chair  10 . Clamp  110  also may permit a user to raise and lower table  108  along chair upright portion  14  and rotate table  108  about chair upright portion  14  to move table  108  into position for use and move table  108  out of the way so that a user may get in and out of chair  10  ( FIG. 1 ) more easily. 
     Clamp  110  may include fifth knob  202 , a stopper  204 , a push plate  206 , and a clamp housing  208 . Fifth knob  202  may include a knob head  210  and a threaded bolt  212  extending from knob head  210 . Stopper  204  may be a solid cylindrical cap having a flat stopper end  214  and a concave end  216  configured to engage a profile of chair upright portion  14 . Concave end  216  may be semicylindrical, U-shaped, or V-shaped, for example, to better mate with a curved or rectangular profile of chair upright portion  14 . Stopper  204  may be attached to push plate  206  and push plate  206  may be attached to threaded bolt  212 . Stopper  204  may be rubber or metal. 
     Clamp housing  208  may include a clamp wall  218  welded to a clamp mounting surface  220 . Clamp housing  208  also may include a door  222  attached to clamp wall  218  by a hinge  224  and a clamp housing threaded hole  228  located in clamp wall  218  opposite of clamp mounting surface  220 . Clamp  110  may be secured to support rod  102  by a weld  230  located between clamp mounting surface  220  and support rod  102 . 
       FIG. 7  is a top partial view of tray  100  with clamp  110  attached to chair upright portion  14 . In operation, door  222  may be opened (as in  FIG. 6 ) to permit clamp housing  208  to receive chair upright portion  14 . With chair upright portion  14  positioned within clamp housing  208 , fifth knob  202  may be tightened to cause concave end  216  of stopper  204  to engage chair upright portion  14 . Door  222  then may be closed to further limit movement of chair upright portion  14  and secured to clamp mounting surface  220  by a door hook  232  that may mate with a hole. Fifth knob  202  then may be tightened until tray  100  is secured to chair  10  ( FIG. 1 ). 
       FIG. 8  is an isometric view of a tray  800  attached to chair  10 . Tray  800  may have features similar to tray  100  with some differences. In this example, the support rod of tray  800  may be “L” shaped rather than include offset  116  to permit moving the tray up and down and rotating the tray relative to chair  10  without having to release clamp  110 . In addition, the table may be formed from two halves, hinges to permit folding the two halves together for shipping. In this regard, tray  800  may include a support rod  802 , a support rod clamp  804 , and a table  806  having a first leaf  808 , a second leaf  810 , and hinges  812 . 
       FIG. 9  is a side view of tray  800 . Support rod  802  may be an “L” shaped support rod that may support table  806  through brackets  104 ,  108  to chair  10  through support rod clamp  804  and clamp  110 . Support rod  802  may include a support rod horizontal portion  814  and a support rod vertical portion  816  connected approximately at ninety degrees to support rod horizontal portion  814 . 
     Support rod clamp  804  may include a support rod clamp tube  818  having a sixth knob  820  removeably secured there through. Support rod clamp tube  818  may be hollow to receive support rod vertical portion  816  and permit support rod vertical portion  816  to move up and down and rotate relative to support rod clamp tube  818 . Similar to knobs  194 ,  196 ,  198 , and  200 , sixth knob  820  may include a head with one side of the head having radial teeth and a threaded bolt extending from that side having radial teeth. The radial teeth may grip and seat a mating surface of support rod clamp tube  818 . When screwed tight, the threaded bolt of sixth knob  820  may touch and restrain support rod vertical portion  816  from moving through compression. Support rod clamp tube  818  may be attached to clamp mounting surface  220  through a weld  822 . 
       FIG. 10  is a section view of table  806  generally taken off line  10 - 10  of  FIG. 8 . As noted, table  806  may include a first leaf  808 , a second leaf  810 , and hinges  812 . Table  806  may be a platform having a table top  824  to receive work items and a table underside  826 . First leaf  808  and second leaf  810  each may be a hinged flat section of table  806  that may abut one another to form a flat surface having a table cavity  828  and may fold on top of each other to reduce a size of table  806 . 
     Hinges  812  may be a jointed or flexible device that may permit pivoting first leaf  808  relative to second leaf  810 . Hinges  812  may include a first L-bracket  830 , a second L-bracket  832 , and a pivot  834 . First L-bracket  830  may include a first L-bracket base  836  and a first L-bracket projection  838  extending approximately ninety degrees from first L-bracket base  836 . Second L-bracket  832  may include a second L-bracket base  840  and a second L-bracket projection  842  extending approximately ninety degrees from second L-bracket base  840 . 
     First L-bracket base  836  and second L-bracket base  840  may be attached to table underside  826 . First L-bracket  830  and second L-bracket  832  each may be attached to pivot  834 . First L-bracket projection  838  and second L-bracket projection  842  may be configured to abut each other and pivot  834  may be positioned in table cavity  828  when table  806  is in an open position. Abutting first L-bracket projection  838  and second L-bracket projection  842  may maintain table  806  in a flat position and prevent the respective leafs from over rotating. 
     To reduce a size of table  806 , table  806  may be removed from brackets  104 ,  106  by removing first knob  194  and second knob  196  ( FIG. 5 ), respectively. With table  806  free from brackets  104 ,  106 , first L-bracket projection  838  and second L-bracket projection  842  may be configured to move about pivot  834  in a direction of first arrow  844  and second arrow  846 , respectively so that table top  824  of first leaf  808  and table top  824  of second leaf  810  may come into contact with one another. 
     The tray may be secured to a portable chair such as a wheelchair and may function as an eating, writing, drawing, or studying table or platform. The tray may be produced from a durable plastic or aluminum and may measure 12 to 16 inches long, ½ inch wide, and may feature an adjustable height. The tray may include a clamp that may enable the tray to be secured to one of the front uprights of a chair. This clamping mechanism may feature a twist knob that may enable the tray to be secured to the upright. This clamp may secure a lower support of the tray to the chair. 
     Two upward extending uprights may be connected to the support with pivoting hardware. This hardware may enable the uprights and the tray mounted to the top of them to be pivoted up and down on demand. When the tray is pivoted upward, it may be in a functional position. A person may now utilize the tray to eat, write, read, and study. A level is an indicator that may establish the horizontal when a bubble is centered in a tube of liquid. The tray may include a level attached to the table to assist a user to position the table horizontally or at a desired angle with more precision. Thus, even if the chair is not level, the table may be adjusted to be level. The tray may include sports logos, such as for football and baseball. 
     When the tray is collapsed, the tray may feature a low profile. This low profile may create a compact unit that may be easily carried and stored after it had been removed from the chair. The tray may include a carrying case and a spring clip may be attached to a top of the table. Metal and/or rubber washers may be provided between mating surfaces. 
     The tray may fulfill a need for a tray that may be secured to a portable chair that may function as an eating, writing, drawing, and/or studying platform. Appealing features of the tray may include its compactness and portability, ease of attachment and use, convenience, durability, functional versatility, and ease of storage. The tray may be utilized by homeowners, campers, anglers, and outdoor sporting event spectators. Disabled persons in a wheelchair may use the tray as well 
     The information disclosed herein is provided merely to illustrate principles and should not be construed as limiting the scope of the subject matter of the terms of the claims. The written specification and figures are, accordingly, to be regarded in an illustrative rather than a restrictive sense. Moreover, the principles disclosed may be applied to achieve the advantages described herein and to achieve other advantages or to satisfy other objectives, as well.