Abstract:
A backrest for a seat is disclosed having a first plurality of forwardly facing openings  8  arranged in an array  7  and second plurality of protrusions  10  arranged in a second array  9.  The arrays are rectangular with substantially equal spacing so that the openings and protrusions are inter-mingled. The arrangement reduces solar heating of the unoccupied seat and allows air flow and perspiration drainage of the occupied seat.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to outdoor chairs, and particularly, but not exclusively, stadium seats installed in those stadia which are not provided with a roof or other covering. 
       BACKGROUND ART 
       [0002]    Such open air stadium seats can be subjected to intense solar radiation making the seat itself very hot when a spectator arrives at a seat to commence viewing a match, such as a cricket match, or other performance. As a consequence, the spectator finds that not only is the general atmosphere hot, but the backrest of the seat is already hot from being subjected to solar radiation. Under these conditions of an elevated temperature, the spectator normally perspires and the perspiration is trapped between the backrest of the seat and the back of the spectator, thereby leading to a shirt back which is sodden and damp with perspiration. 
       GENESIS OF THE INVENTION 
       [0003]    The genesis of the present invention is a desire to provide an improved backrest which to at least some extent ameliorates the above described situation. 
       SUMMARY OF THE INVENTION 
       [0004]    In accordance with a first aspect of the present invention there is disclosed a backrest for outdoor chairs including stadium seats, said backrest comprising a first plurality of forward facing openings formed in the front of said backrest, and a second plurality of protrusions formed on the front facing inter-opening portions of said backrest, said openings reducing the area of said backrest front on which sunlight can be incident and said protrusions reducing the area of contact of said backrest with a sitter. 
         [0005]    In accordance with a second aspect of the present invention there is disclosed a method of cooling a seat having a backrest subjected to solar radiation, said method comprising: 
         [0006]    (i) forming a first plurality of forward facing openings in the front of said backrest, and 
         [0007]    (ii) forming a second plurality of protrusions on the front facing inter-opening portions of said backrest, 
         [0008]    wherein said openings reduce the area of said backrest front on which sunlight can be incident and said protrusions reduce the area of contact of said backrest with a sitter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Some embodiments of the invention will now be described, with reference to the accompanying drawings in which: 
           [0010]      FIG. 1  is a perspective view of the front of a stadium seat, or other outdoor chair, having the backrest of the first embodiment, 
           [0011]      FIG. 2  is a partly sectional and partly perspective view showing a substantially vertical section through a part of the backrest of  FIG. 1  and illustrating the front of the backrest in perspective, 
           [0012]      FIG. 3  is a partial vertical cross-sectional view through the backrest of the chair of  FIG. 1 , and 
           [0013]      FIG. 4  is a view similar to  FIG. 2  but of a second embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    As seen in  FIG. 1 , the outdoor chair  1  has a seat  2  and a backrest  3 . The backrest  3  has a front surface  4  and a rear surface  5  ( FIG. 3 ). The backrest  3  has a first regular rectangular array  7  of forward facing openings  8  and a second regular rectangular array  9  of protrusions  10 . As illustrated, the two arrays  7 ,  8  are substantially rectangular and substantially equally spaced so that each pair of protrusions  10  has a forward facing opening  8  therebetween and each pair of openings  8  has a protrusion  10  therebetween. This applies moving both vertically and horizontally across the back rest  3 . However, other array shapes or patterns can be used to achieve a different appearance from that illustrated in  FIG. 1 . 
         [0015]    Turning now to  FIG. 2 , it will be seen that the openings  8  preferably extend all the way through the backrest  3  and thus define a passageway  18  having a rear facing aperture  28 . As best seen in  FIG. 3 , the passageway  18  is inclined downwardly moving from front to rear so that for each passageway  18  the corresponding forward facing opening  8  is located above the corresponding rear facing aperture  28 . 
         [0016]    In addition, each of the protrusions  10  preferably has three dimples, bumps or crowns  12  which may be substantially hemispherical, but need not be. The protrusions  10  could also have either two crowns or only a single crown. 
         [0017]    As indicated in  FIG. 3 , solar radiation  14  which is incident upon the front  4  of the backrest  3  is not incident on the entire backrest but is only incident on that portion of the backrest which interconnects the openings  8 . As a result, the surface area of the backrest  3  which actually receives the solar radiation  14  is substantially reduced relative to an equivalent backrest without openings  8 . As a consequence, the total amount of solar energy incident upon the backrest  3  is reduced since some of the rays of the solar radiation  14  pass directly through the backrest  3  and thus their heating energy is expended elsewhere. 
         [0018]    Furthermore, since the passageways  18  are upwardly inclined, the heating of the material of the backrest  3  caused by the solar radiation  14  incident upon it, warms the air in the passageway  18  which thus rises and thereby exits the passageway  18  via the forward facing openings  8 . In this way, a natural convective air flow is created which cools the entire backrest  3  prior to the arrival of a spectator. 
         [0019]    Once the spectator does arrive and sits on the seat  3 , the back of the spectator is incident upon the backrest  3 . However, the back of the spectator only comes into contact with the tops of the crowns  12  so that the surface area of the backrest  3  in contact with the shirt of the spectator is very much reduced. Furthermore, the abovementioned convective air flow can continue since the upwardly flowing air can move out of the forward facing openings  8  and between the protrusions  10  and continue on in an upward path until it eventually reaches the top of the backrest  3 . 
         [0020]    In addition, should the spectator perspire, any perspiration can enter the forward facing openings  8  and move downwardly through the passageway  18  and exit the backrest by the rear facing aperture  28  as schematically illustrated by the downwardly directed arrows in  FIG. 3 . 
         [0021]    In a similar manner, the passageways  18  enable rain falling upon the seat when unoccupied, to wash dirt and water into the passageways  18  and thereby assist in keeping clean the front  4  of the backrest  3 . 
         [0022]    Furthermore, the crowns  12  of the protrusion  10  are preferably asymmetrical and have a more gradual curve on the upper portion and a more pronounced curve on the lower portion. This asymmetry assists gravity induced shedding of water and dirt from the front  4  of the backrest  3 . 
         [0023]    Turning now to  FIG. 4 , a second embodiment in the form of a backrest  33  is illustrated in which equivalent portions have their designation member increased by  30  relative to the corresponding portion of the first embodiment. The passageways  48  are approximately frusto-conical in shape to provide an improved draft angle for extraction from the mould. In addition, the rear facing apertures  58  are now considerably larger in diameter than the forward facing openings  38 . Also at least the lower rim of the rear facing apertures  58  is preferably bevelled. 
         [0024]    Furthermore, in the arrangement of  FIG. 4  an alternative flow path for hot air generated either by the sun or by a sitter is available. The alternative path is into the forward facing openings  38 , from front to rear via the passageways  48 , and exiting from the backrest  33  via the top portions of the passageways  48 . 
         [0025]    Still further, the passageways  48  are angled more steeply than the passageways  18  with the consequence that more sunlight is available to pass directly through the passageways  48  without striking the backrest  33  at all. 
         [0026]    The foregoing describes only two embodiments of the present invention and modifications, obvious to those skilled in the furniture arts, can be made thereto without departing from the scope of the present invention. For example, although the invention had its conception in regard to outdoor furniture, the invention is not limited to such furniture and can be used for indoor furniture, especially within non air conditioned buildings in hot climates. Similarly, the invention is also applicable to seats in addition to backrest. 
         [0027]    Now that embodiments of the invention have been described and the invention ascertained, it will be appreciated that the invention differs from those prior art seats having backrests woven from cane strips to provide an aesthetically pleasing pattern, or moulded plastic backrests having openings therein to save material costs, since neither of these backrests provide the thermodynamic advantages described above. 
         [0028]    The term “comprising” (and its grammatical variations) as used herein is used in the inclusive sense of “including” or “having” and not in the exclusive sense of “consisting only of”.