referring to the drawings and initially to fig1 there is shown a perspective view of a wheeled cart usefull for storing tennis balls or the like which is provided with a shading device 30 according to one aspect of the present invention . in this figure is shown the ball storage compartment 28 which includes a front wall portion 2 , a rear wall portion 4 , a left side wall portion 6 , a right side wall portion 8 , and floor portion 10 . the top portion 12 is open by virtue of the absence of any wall portion . thus , the ball storage compartment resembles an open box . there is a handle means 14 disposed at the upper portion of the rear wall 4 . each of the front wall portion 2 , rear wall portion 4 , left side wall portion 6 , right side wall portion 8 and floor portion 10 includes an inner surface which faces the interior of the storage compartment and an outer surface which faces the exterior of the storage compartment . the shading device comprises a first generally u - shaped member 16 , a second generally u - shaped member 18 ( fig3 - 5 ) and a first means for securing the members together 20 a , and a second means for securing the members together 20 b . there is a means for attaching the first member to the inner portion of the left side wall portion 22 . also shown in fig1 are wheels 24 and the canopy 26 disposed about the second generally u - shaped member . in fig2 there is shown a perspective view of a ball cart according to the prior art , which includes a ball storage compartment 28 which includes a front wall portion 2 , a rear wall portion 4 , a left side wall portion 6 , a right side wall portion 8 , and floor portion 10 . the top portion 12 is open by virtue of the absence of any wall portion . thus , the ball storage compartment resembles an open box . there is a handle means 14 disposed at the upper portion of the rear wall 4 . each of the front wall portion 2 , rear wall portion 4 , left side wall portion 6 , right side wall portion 8 and floor portion 10 includes an inner surface which faces the interior of the storage compartment and an outer surface which faces the exterior of the storage compartment . [ 0020 ] fig3 shows a perspective view of shading device 30 according to one form of the invention which comprises a first generally u - shaped member 16 , second generally u - shaped member 18 , first means for securing the first generally u - shaped member to the second generally u - shaped member 20 a , second means for securing the first generally u - shaped member to the second generally u - shaped member 20 b , and canopy 26 disposed about the second generally u - shaped member . [ 0021 ] fig4 shows a perspective view of the frame portion of a shading device 30 according to the invention which frame portion comprises a first generally u - shaped member 16 , second generally u - shaped member 18 , first means for securing the first generally u - shaped member to the second generally u - shaped member 20 a , and second means for securing the first generally u - shaped member to the second generally u - shaped member 20 b . [ 0022 ] fig5 shows and exploded view of the frame portion of a shading device 30 according to the invention which frame portion comprises a first generally u - shaped member 16 , second generally u - shaped member 18 , first means for securing the first generally u - shaped member to the second generally u - shaped member 20 a , and second means for securing the first generally u - shaped member to the second generally u - shaped member 20 b . the present invention generally comprises a framework comprising two generally u - shaped members which are connected to one another by a pair of means for securing the members together , and in which there is a canopy disposed about one of the members . the generally u - shaped members and means for connecting them to one another ( collectively “ the frame members ”) may be constructed of any material which is of sufficient strength to be attached to the wall of a basket or ball cart while supporting the weight of the remaining members of the frame and canopy . preferred materials of construction include without limitation metals such as steel or aluminum , woods , and polymeric materials such as pvc , polypropylene , polyethylene , etc . in one preferred form of the invention the frame members comprise aluminum . in another preferred form of the invention , the frame members comprise pvc . according to one preferred form of the invention , the frame members are constructed of hollow tubular stock , wherein the generally u - shaped members and means for securing them to one another are of such diameter to enable one to slidably fit into the other . for example , in the embodiment shown in fig5 the inner diameter y of the first generally u - shaped member 16 is slightly larger than the outer diameter of the end x of the securing means 20 a . such dimensioning enables an adjustable height dimension for the shading device 30 when there are holes 31 disposed about the securing means 20 a which may be selectively locked into a desired position by means of a pin 33 which passes through the diameter of the first generally u - shaped member 16 by selecting which hole the pin is disposed through when the securing means 20 a is engaged in the first generally u - shaped member 16 . other means for providing an adjustable fit between concentric tubes known to those skilled in the art are functionally equivalent , such as a threaded screw being located at 33 which may be turned against the outer surface of the securing means 20 a . similar dimensioning may be effected for the end portions p and q of the securing means 20 a and the ends of the second generally u - shaped member 18 , as well as provisions 31 and 33 for adjusting the length l of the overhang of the canopy portion . the inner diameter of the first generally u - shaped member may be larger than the outer diameter of the securing means . the inner diameter of the securing means may be larger than the outer diameter of the first generally u - shaped member . the inner diameter of the second generally u - shaped member may be larger than the outer diameter of the securing means . the inner diameter of the securing means may be larger than the outer diameter of the second generally u - shaped member . whichever dimensions are selected , for such an embodiment , the result is that the means for securing the first member and the second member together is slidably engageable with at least one of the first member or said second member , or both . according to yet another embodiment , the frame members may be all of a single construction . according to another form of the invention , only the second generally u - shaped member is slidably engageable with the means for securing and the first generally u - shaped member and securing means are of a single construction . according to another form of the invention , only the first generally u - shaped member is slidably engageable with the means for securing and the second generally u - shaped member and securing means are of a single construction . the invention also contemplates frame members having cross sections different from circular , including without limitation , square cross sections , rectangular cross sections , oval cross sections , hexagonal cross sections , etc . the means for attaching 22 the first generally u - shaped member 16 to the side wall portion of the ball storage compartment 28 may be any means known to those skilled in the fastener arts , such as brackets and screws , clamps , rivets , twine , nylon zip - strips , wire ties , welds , etc . according to a preferred form of the invention , removable clamp brackets are employed . the canopy portion 26 may be comprised of any material which is capable of blocking the rays of the sun , and includes without limitation wood , plastic sheet , metal sheet , screens , canvas , vinyl sheet , cotton , or other cloth materials . according to one preferred form of the invention , the canopy portion 26 comprises canvas . the canopy portion 26 may be affixed to the second generally u - shaped member 18 by means of stitching , glues , twine , ties , or a sleeve which is sewn - in to the fabric of the canopy portion 26 when a fabric is selected , so as to enable the canopy to be slid over the second generally u - shaped member 18 in a snug fit . as mentioned above , the shading means comprises a first generally u - shaped member which defines a first plane , a second generally u - shaped canopy - supporting member which defines a second plane , and a means for securing the first member and the second member together . the means for securing is configured so that the first member , second member , and means for securing all reside only within the first plane or the second plane , and wherein a single angle is defined by the intersection of said first plane and said second plane . preferably , the angle of intersection of the first and second planes is any angle in the range of about 45 to 120 degrees . more preferably , the angle of intersection of the first and second planes is any angle in the range of about 60 degrees to 100 degrees . in one preferred form of the invention , the angle of intersection of the first and second planes is about 80 degrees .
provided herein is a shading device useful in conjunction with wheeled carts which are used by tennis instructors to train students . a shading device according to the invention is adapted to be retrofitted to existing tennis ball storage carts . use of the present invention provides a tennis ball storage cart having a shaded area external to the left or the right side of the cart , where an instructor may stand , shaded from the sun while serving balls to a student or otherwise observing court activity . by use of the invention , an instructor may spend many hours instructing students on sunlit days without being effected by the harmful effects of the sunlight .