Abstract:
A folding chair having adjustable rear legs for use on flat, even ground and in addition, on sloping terrain from about zero degrees to twenty degrees and being continuously adjustable over this range by a user in a seated position.

Description:
[0001]    This application claim benefit of U.S. Provisional Patent Application No. 60/220,626, filed Jul. 25, 2001. 
     
    
     
       BACKGROUND OF INVENTION  
         [0002]    This invention relates to rugged, yet lightweight, outdoor furniture that is continuously adjustable to accommodate varying terrain.  
           [0003]    Spectators of various outdoor events, such as golf, baseball, soccer, fireworks displays and parades, for example, typically use lawn furniture for seating during the event. Seating is commonly placed on nearby grass areas that may or may not be flat. A broad range of portable, folding and compact outdoor furniture is available in today&#39;s market but their designs are optimized for level or horizontal surfaces. The chairs are not the problem. Rather it is the way the various portable chairs are used on sloping ground.  
           [0004]    Depending on the angle of the ground or slope, the seat of most chairs remains roughly parallel (actually around  6 ?? relative to the ground upon which it is situated. As the slope of the ground increases, the angle of an individual&#39;s seated position relative to horizontal decreases. As the seating angle decreases (to below 0°), the seated individual&#39;s constant attempt to brace himself to keep from sliding out of the chair or to keep the chair from toppling does not create a situation of relaxed comfort, the goal of sitting in a chair in the first place. At some point of discomfort, individuals with nothing more than a fixed-leg lawn chair will elect to sit on the ground or try to find flatter ground for their chairs rather than fight the slope.  
           [0005]    Unfortunately, flatter ground simply may not be available or may offer an inferior viewing perspective of the event being observed.  
           [0006]    In order to compensate for various slopes, the legs of a chair must be easily and continuously adjustable to adapt to a wide degree of slopes in order to maintain a somewhat normal and comfortable seating angle. In addition, since a portable chair may be subject to rules and restrictions at certain spectator events, a chair&#39;s capacity to adapt to sloping terrain seating may be subject to certain physical limitations. For example, the rules covering portable seating at the Memorial Golf Tournament held at the Muirfield Village Golf Club in Dublin, OH. prohibit, among other things, chairs with arms and chairs over a certain height.  
           [0007]    Several attempts to solve this seating problem have resulted in patents being granted patents for adjustable portable chairs. However, as will be evident from the discourse below, each of these attempts have shortcomings, which prevent them from fully achieving a solution to the slope problem.  
           [0008]    For example, U.S. Pat. No. 4,772,068, issued to Glecker et al., discloses a portable fishing chair intended for use on sloping terrain by fishermen and campers. Glecker et al.&#39;s chair employs and adjustable extension, which is limited to three fixed positions, which accommodates only three different degrees of slope. The chair is not easily adjustable from the multiple, fixed seating positions and appears relatively complicated. In addition, the chair has arms, which would prevent it from being used at certain events.  
           [0009]    U.S. Pat. No. 5,494,333, issued to Wilson, discloses a chair, which provides either three or four individually adjustable legs such that the chair can be used on a variety of terrain. Like Glecker et al. the number of positions is fixed and thus cannot conform continuously to a wide degree of slopes. The legs do not appear to be easily adjustable by a user in a seated position. Like the Glecker chair, the Wilson chair has arms and thus would not conform to events where armed chairs are not permitted.  
           [0010]    U.S. Pat. No. 5,522,642, issued to Herzog, discloses a folding stool, with individually adjustable legs, that is adaptable for use on various sloped terrains. However, like the other chairs in the cited art, the legs are not adjustable from a seated position and adjustment is limited to a fixed number of angles based upon predetermined, fixed hole spacings. While Herzog has no arms, its ability of increasing the height of the stool for better viewing over crowds would violate chair policies for events, which regulate the maximum allowable seat height for portable seating.  
           [0011]    U.S. Pat. No. 6,036,148, issued to Shank, discloses a folding outdoor chair having four, independently adjustable legs. However, like the other chairs in the cited art, the legs do not appear to be easily adjustable from a seated position and would require multiple settings of the various legs.  
           [0012]    What is needed is a sturdy, durable and portable lawn chair that has a comfortable seat and which can be easily adjustable to varying terrain from a seated position.  
         SUMMARY OF THE INVENTION  
         [0013]    The present invention provides:  
           [0014]    A chair for maintaining a normal seated position on flat, horizontal ground continuously up to twenty degree grades or slopes by utilizing a quick and sturdy rear leg leveling adjustment;  
           [0015]    A portable chair that has a comfortable and flexible seat;  
           [0016]    A chair that is easily adjustable from a seated position;  
           [0017]    Solid construction, high quality materials, lightweight and portable;  
           [0018]    A portable chair that folds flat for storage and easy portage;  
           [0019]    A portable chair designed within specified limitations on chair seat height and width and chair back height for select events prohibiting certain chairs, i.e., lawn chairs, solid chairs and chairs with arms;  
           [0020]    A portable chair that can be used on flat ground in addition to sloped terrain; and  
           [0021]    A portable chair with suitability for commercial and rental applications with sleek look, durability, function and design.  
           [0022]    Another feature of one aspect of the invention is to provide a folding chair having adjustable legs for use on flat, even ground and in addition, on sloping terrain from about zero degrees to twenty degrees continuously comprising front leg assembly having two leg members with a first, upper fixed horizontal cross support to support a portion of a seating material. A lower fixed horizontal cross brace is located near the bottom of the leg members, and a back support assembly is pivotally attached to the upper rear leg assembly. The back support assembly is comprised of: two parallel sides pivotally attached at one end to the outer sides of the front leg assembly; a horizontal back support member connected between the upper extents of said two parallel sides and providing a user with back support when unfolded; and a lower horizontal stop member located near the lower extents of said parallel sides providing for a predetermined angle of said back support when unfolded. Also included is an upper rear leg assembly consisting of two leg members attached near their upper extents by a second, fixed horizontal cross support to support a portion of said seating material, a horizontal cross brace fixed near the bottom of the legs. C-type structural channel are provided and fixed to the rear facing surface of each upper rear leg to slidably receive at least one channel slide member. A lower rear leg assembly is also provided and consists of: two lower leg members, each containing two channel slide members, one of which is slidably fixed within the upper portion of each of said channels and the other being attached to a screw-type knob, providing for positioning adjustment of said lower leg members with respect to said upper rear leg members and having two horizontal cross braces, one fixed between and near the tops of the leg members and the other near the bottom of the leg members. This aspect of the invention also includes a seat consisting of a seating material suspended between the first and second upper fixed horizontal cross supports. The seating material is comprised of a flexible material, which can be either natural or man-made.  
           [0023]    These and other features, aspects and advantages of the present invention will become better understood with the regard to the following description, appended claims and accompanying drawings. 
       
    
    
     DETAILED DESCRIPTION OF DRAWINGS  
       [0024]    [0024]FIG. 1 is a perspective view of one embodiment of the claimed invention shown on a twenty-degree slope;  
         [0025]    [0025]FIG. 2 is a perspective view of one embodiment of the claimed invention with the back support fully unfolded on a twenty-degree slope;  
         [0026]    [0026]FIG. 3 is a side elevational view of one embodiment of the claimed invention nearly fully folded for storage or portage;  
         [0027]    [0027]FIG. 4 is a side elevational view of one embodiment of the claimed invention with the back support folded on level ground;  
         [0028]    [0028]FIG. 5 is a side elevational view of one embodiment of the claimed invention with the back support fully unfolded on level ground; and  
         [0029]    [0029]FIG. 6 is a side elevational view of one embodiment of the claimed invention with the back support fully unfolded on a twenty-degree slope. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]    Referring to FIG. 5, a folding chair  10  according to a first embodiment of the present invention is shown. The front leg assembly  12  consists of two front parallel leg members  14 ,  14 ′ (not shown) extending to the height of the seat and being permanently connected together at the bottom by a horizontal cross brace  16  and at the top by a horizontal cross support  17 . The lower horizontal cross brace  16  may be fixed nominally one inch above the bottom of the front leg members  14 ,  14 ′ in order to provide a solid foot rest, and to limit the amount the legs penetrate soft ground  50 . The upper horizontal cross support  17  strengthens and stabilizes the front leg assembly  12  and provides support and a means for attaching the rear portion of the seat material  23 .  
         [0031]    Pivotally attached to the front leg assembly  12  is the back rest assembly  13  consisting of two parallel sides  21 ,  21 ′ (not shown) that are movably retained as at point “A” toward the lower extent of one end to the outer sides of the front leg assembly  12  and the other end by a horizontal back support  18 , which further strengthens and stabilizes the chair and provides sufficient back support when fully unfolded. Details of the pivoting mechanism is not shown, but may consist of a number of various nut and bolt arrangement, as would be appreciated and understood by one skilled in the art. A lower horizontal cross brace  19  (shown in phantom) may be supplied to provide structural stability and a physical stop for the backrest assembly against the front leg members  14 ,  13 ′ when fully unfolded. Alternately, horizontal cross support member  17  may be constructed to extend beyond the width of the front leg members  14 ,  14 ′, to provide a back rest stop when engaging rearward faces of parallel sides  21  and  21 ′.  
         [0032]    The rear leg assembly  20  consists of two separate sub-assemblies. The upper or forward rear assembly  22  comprises two forward rear assembly leg members  24 ,  24 ′ (not shown) that are pivotally attached in a conventional manner, as at point “B”, to the front leg assembly  12 . To provide stability, a cross brace  28  is fixed horizontally near the bottom of and between the two forward rear assembly leg members  24 ,  24 ′ and at the top by a fixed, horizontal cross support  26 , which also provides support and means for attaching the front portion of seat material  23 . Attached to the rear facing surfaces of the fixed forward rear assembly  22  are slotted “C” channels  30 ,  30 ′ (not shown), such as may be commercially available as UNISTRUT™. A stop mechanism (not shown) is provided within each channel  30 ,  30 ′, at about their lower extents, to prevent the lower rear leg assembly  32  from completely disengaging the channels during adjustment of adjusting knob  46 . The stop mechanism is positioned to provide a user with a chair that sits on a horizontal, i.e. 0°, surface when the lower leg assembly is fully extended.  
         [0033]    The lower rear leg assembly  32  comprises two vertical leg members  36 ,  36 ′ (not shown), which are permanently connected by an upper cross brace  38  and lower cross brace  40 . The lower cross brace  40  is fixed approximately one inch above the bottom of the leg members  36  to provide structural stability and to limit the amount the ends of the leg members penetrate soft ground  50 . In addition, each lower rear leg member  36 ,  36 ′ has an upper channel slide member (not shown) located near the tops of the respective leg members and an adjustable, lower channel slide member (not shown) secured with an adjusting knob  46 , each channel slide member having a head porting slidably engaged within the flanges of the slotted “C” channels,  30 ,  30 ′. Loosening and then tightening adjustable knob  46  enables engagement between the upper rear leg assembly  22  and the lower rear leg assembly and provides for variable and easy adjustment of the angle of the chair by the user while in a seated position (see also FIG. 6). Referring additionally to FIG. 6, the folding chair  10  is shown with the lower rear leg assembly  32  in a nearly fully retracted position to accommodate a 20° slope. Carrying strap  48  may be provided, preferably attached at its ends to pivot point “A”. So attached, when the rear leg assembly is in the retracted position, the chair will automatically collapse under the force of gravity, into its fully folded, carrying configuration.  
         [0034]    The seat material  23  preferably consists of natural and/or man-made fabric or other suitable material which is attached to the front leg assembly&#39;s top horizontal cross support  17  and the rear leg assembly&#39;s top cross supports  15 ,  23 , which when unfolded, provides a sturdy, yet flexible and comfortable seat which has been weight tested to 260 pounds. The seat material  23  may be secured to cross supports  15  and  23  with fasteners, such as nails, screws, staples or the like or sewn with loops on the front and rear portions to accommodate the cross supports passing through the loops without being securely fastened.  
         [0035]    The chair  10  in FIG. 5 is preferably constructed from any combination of metal, wood, composite materials, or molded from a variety of suitable plastic material and includes a flexible seat  23 , preferably manufactured from canvas, or other woven fabric, plastic, or other flexible and durable material.  
         [0036]    It is to be understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangements of parts described and shown.