Abstract:
An improved foldable stadium seat having a seat portion and a backrest. The stadium seat has adjustable hooks that can engage different width bleachers. The hooks also reverse to secure the backrest to the seat portion for easy carrying. The hooks have retention pins that engage securing holes to conveniently lock the hooks in their predetermined desired locations. The hooks can also serve as feet for an elevated chair for use on any flat surface.

Description:
FIELD OF THE INVENTION 
     The present invention relates to stadium seats, and in particular, it relates to foldable stadium seats that attach to stadium bleacher seats so as to provide the user with a padded seat cushion and a padded backrest. 
     BACKGROUND OF THE INVENTION 
     Many stadiums today have bench seats (bleachers) instead of individual seats. Bleachers have traditionally been made of long wooden planks with no backrest. Many modern and refurbished stadiums use bleachers made of metal, still with no backrest. 
     Sitting on bleachers for long periods of time can be uncomfortable in two ways. First, the bleacher is hard and can be uncomfortable to sit on for long periods of time. Secondly, sitting on a seat with no backrest can strain the upper and lower back. 
     To help solve this problem, cushions can be placed on the hard wooden or metal surface. These cushions address the pain of sitting on a hard surface, but they do not address strain on the upper and lower back. 
     Prior art solutions to back pain in bleacher seating provided the user with a padded seat combined with a backrest. The most widely used design is a foldable seat that has a seat portion and a backrest that are foldably connected. Hook(s) on the seat portion engage the front underneath portion of the bleacher to allow the user to lean back in the seat and not tip backwards. The seat portion can have a single hook in the center of the seat portion, or there can be two hooks, as set forth in U.S. Pat. No. 2,509,420 and U.S. Pat. No. 3,066,980, with one hook on each side of the seat portion. 
     There are drawbacks to these designs, however. First, the hook openings must match the thickness of the bleacher. If the hook opening is too small, it will not engage the bleacher. If the hook opening is too large, then the user will tilt backwards until the hook engages the bottom of the bleacher, which is undesirable. Therefore, prior art designs can be used only with stadiums with bleacher thicknesses that match the size of their hook opening. The user cannot use a single seat in two different stadiums that have two different bleacher thicknesses. Or, if a stadium retrofits its bleachers with thicker bleacher widths, then the seat becomes obsolete. 
     There is a need for a stadium seat that can effectively be used with varying thicknesses of bleachers. 
     Another drawback to the prior art devices is that they do not adequately secure the backrest to the seat portion for easy carrying when the stadium seat is in its folded/closed position. Some designs use the hook under the seat to engage a loop on the backrest, or to engage the backrest itself. But those designs fail to securely hold the backrest to the seat portion securely in a manner whereby the hooks cannot inadvertently become undone. 
     There is a need to provide an easy and effective way to secure the backrest to the seat portion for easy carrying when the seat is in its folded position. 
     SUMMARY OF THE INVENTION 
     The foregoing problems have been overcome by present invention, which is an improved foldable stadium seat. The improved stadium seat has a seat assembly comprising a seat pad secured to two parallel, spaced apart, seat rods. A backrest assembly, comprising a backrest pad secured to two parallel, spaced apart, backrest rods, is swingably attached to the seat assembly by a hinge. 
     The seat has two positions, an open position and a closed position. In the open position, the seat assembly and the backrest assembly form an approximate right angle. To put the stadium seat in its closed position, the backrest assembly swings toward the seat assembly so that the backrest pad lies flat against the seat pad. 
     There are two U-shaped hooks each having a spring loaded retention pin protruding from one side of the U. The seat rods are hollow in the ends farthest away from the hinge such that the one side of each U-hook with the retention pin inserts into the seat rods. The U-hooks rotate about the seat rods. 
     There are a series of retention pin holes in a line around each of the U-hooks whereby the retention pin protrudes through one of the retention pin holes to engage a securing hole in the seat rod thereby fixing the angular position of the U-hook relative to the seat pad. Each retention pin hole position represents a different desired angular position of the U-hooks as they rotate relative to the seat rods. Changing this angle changes the effective width of the opening between the hook end and the seat pad. Therefore, hooks can be set to properly engage different bleachers having different thickness by changing and locking in different U-hook angles. 
     In the closed position, the seat and seat back are locked together by means of a detente in the U-hook that engages the corresponding back rest rod. By compressing the seat and seat back together, the U-hook can be rotated to disengage the back rest rod and thus allowing the seat back to swing out of its closed position. 
     In an alternate embodiment, the stadium seat has 4 U-hooks, one on each corner of the seat. The 4 U-hooks can fully secure the seat to the bench for activities such as rowing a row boat. The 4 U-hooks can also serve as feet for an elevated seat for use on any flat surface. 
     This seat is advantageous over the prior art because the effective hook opening can be changed and locked to match different bleacher thickness. Further, the seat utilizes the hooks to secure the backrest to the seat pad when the seat is in its closed position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevated perspective view of the foldable stadium seat in its open position. 
     FIG. 2 is an elevated perspective view of the foldable stadium seat in its closed and locked position. 
     FIG. 3 is a side view of the hinge plate of the seat. 
     FIG. 4 is a composite side view showing the stadium seat in its open position and in phantom in its closed position. 
     FIG. 5A is a side schematic view illustrating how the U-hook engages a thick bleacher seat. 
     FIG. 5B is an end view of the hook in FIG. 5A taken along line 5B--5B in the direction of the arrows and illustrating in phantom the position of the hook for a thinner bleacher seat. 
     FIG. 5C is a cross sectional view of a portion of the structure shown in FIG. 5A taken along line 5C in the direction of the arrows. 
     FIG. 6A is a top view of the hinge. 
     FIG. 6B is a rear elevational view of the hinge plate. 
     FIG. 7 is a composite side view of the stadium seat illustrating the alternate embodiment having four U-hooks. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 and 2, the preferred embodiment of the stadium seat is designated in its entirety by the number 1. The stadium seat 1 has a backrest assembly 10, a hinge 20, and a seat assembly 30. 
     The backrest assembly 10 has a backrest pad 12 and two parallel spaced apart backrest rods 14. The backrest pad 12 can be made of any rigid material. Preferably the front surface of the backrest pad 12 is padded for comfort. 
     The backrest rods 14 are attached to the backrest pad 12 and extend down to the hinge 20. The backrest pad 12 is most comfortable when it does not extend all the way down the backrest rods 14 to the hinge means 20. 
     The seat assembly 30 has a seat pad 32 and two parallel spaced apart seat rods 34 which are attached to the underneath surface of the seat pad 32 and held in a substantially parallel configuration. The seat pad 32 can be made of any rigid material and is preferably padded on its top surface for comfort. 
     The hinge 20 is illustrated in FIGS. 3, 4, 6A and 6B. The preferred embodiment uses two hinges 20, one for each side of the stadium seat 1. Each of the hinges 20 includes a hinge plate 21 which is bolted, riveted, or otherwise attached to the backrest rods 14 through boltholes 22 and 24, and pivotally connected to the seat rods 34 at bolthole 26. 
     The hinge plate 21 has a semicylindrical channel adaptor 27 into which the back rest rod 14 nests when it is attached to the hinge plate 20 to provide a superior means to secure the back rest rod 14 to the hinge 20. 
     The hinge plate 21 has a horizontal gusset 28 on its bottom surface that extends away from the seat rod. The gusset 28 has a bottom surface 29 that contacts the top surface of bleacher seat B during use to prevent the stadium seat 1 from sliding forward once it is engaged onto the bleacher. 
     When the stadium seat 1 is in its open position, the hinge 20 secures the backrest assembly 10 relative to the seat assembly 30 such that the two assemblies form an angle that is slightly larger than 90 degrees. The hinge 20 pivots around bolthole 26 such that the backrest pad 12 tilts forward until it lays flat against the seat pad 32. When the stadium seat 1 is in this closed position, the seat rods 34 and the backrest rods 14 are substantially parallel to each other. While it is desirable to have a hinge design that allows the backrest to lay flat against the seat pad by making the seat rods and backrest rods parallel in the folded position, it is not necessary to the design of the chair. 
     The stadium seat 1 is held in place on the bleacher seat by two U-hooks 40 at the front of the seat assembly as illustrated in FIGS. 4-5. The U-hook 40 has three sections: the bleacher hook portion or side 42, the extension portion 44, and the swivel portion or side 46. The bleacher hook portion 42 engages the bottom front side of the bleacher B to prevent the stadium seat 1 from moving or tilting backwards during use. The extension portion 44 has a length equal to the thickness of the thickest bleacher intended to be used with the stadium seat 1. The preferred embodiment has an extension portion 44 with a length of 2.75 inches, which is the width of a standard metal bleacher. 
     The swivel portion 46 is round and has an outside diameter slightly less than the inside diameter of the seat rods 34. The ends of the seat rods 34 opposite from the hinges 20 are hollow such that the swivel portion 46 of the U-shaped hooks 40 inserts therein. The U-hooks 40 rotate about the seat rod 34 such that the effective opening between the side portion 42 of the U-hook 40 and the seat rods 34 can be reduced to accommodate smaller bleacher thicknesses, as illustrated in FIG. 5B. 
     The swivel or side portion 46 has a spring loaded retention pin 50 that protrudes from the side of the swivel side portion 46 adjacent to the end of the U-shaped hook 40, through one of three retention pin holes 52, as illustrated in FIGS. 5A-5C. The retention pin 50 is flush with the swivel portion 46 of the U-hook 40 when sufficient inward pressure is exerted onto the pin 50. 
     The U-hooks 40 have three retention pin holes 52 in a line around the swivel portion 46 as shown in FIG. 5C. The retention pin 50 protrudes through a retention pin hole 52 to engage a securing hole 54 in the seat rod 34, which secures the angular position of the U-hooks 40 as they rotate about the seat rods 34. The three retention pin holes 52 are positioned such that the U-hooks 40 alternately have effective opening widths from the seat rods of 1.00 inches, 1.50 inches, or 2.75 inches (when the U-hooks are fully extended downwards). 
     The preferred embodiment has two opposing securing holes 54 substantially in the horizontal plane, and retention pin holes 52 as illustrated in FIG. 5C. The retention pins use one securing hole for the 90° and 30° positions, and the other securing hole for the 45° position. 
     The U-hooks 40 swivel around such that they engage the backrest rods 14 when the stadium seat 1 is in its closed position, as illustrated in FIG. 2, and as illustrated in phantom in FIGS. 4 and 7. U-hooks 40 have detents 48 that engage the backrest rods 14. The U-hooks securely hold the backrest rods 14 in place, which in turn secures the stadium seat 1 in its closed position. The stadium seat 1 can be conveniently carried in the closed and locked position whereby the user cannot inadvertently unlock and unfold the seat without first disengaging the U-hooks 40 from the backrest rods 14. By compressing the backrest and seat pads 12 and 32 together, detente 48 can be swiveled away from the backrest rods 14 to unfold the seat 1 into operable position. 
     While the preferred embodiment has only 3 retention pin holes 52 on each U-hook 40, the number of retention pin holes 52 and their positions can be varied depending on the number of bleacher thicknesses the user wants to accommodate and the thicknesses of those bleachers. 
     In the event that bleacher seats are built that have different widths from the front to the back, different sets of holes 54&#39; can be provided along the length of either the seat rods 34 or the U-hooks 40 to accommodate different lengths of the swivel portion 46 inside the seat rods 34 to accommodate the different bleacher seat widths. 
     In an alternate embodiment, the stadium seat 1 has four U-hooks 40, as illustrated in FIG. 7. The opposing four U-hooks 40 have two purposes. First, four U-hooks 40 secure the stadium seat around both sides of a bleacher seat for added stability. This embodiment is especially good for use on row boats that have bleacher type seats. Second, rubber pads 60 can be added to the outside bottom surface of the U-hooks 40, as illustrated in FIG. 5A. When all four U-hooks are in their downward position, the seat can be placed on any flat surface and used as an elevated seat. This is especially useful for outdoor uses such as backpacking. 
     It is to be understood that the present invention is not limited to the sole embodiment described above and illustrated herein, but encompasses any and all variations falling within the scope of the appended claims.