One piece plastic chair

Abstract

A one piece integrally formed moulded plastic chair ( 11 ) is disclosed having a seat ( 2 ), backrest ( 3 ) and legs ( 4 - 7 ). A U-shaped rib ( 19 ) extends between the upper regions of the rear legs ( 6, 7 ) to cross-brace same. A gap ( 24 ) is proved between the cross piece ( 20 ) of the rib ( 19 ) and the underside of the seat ( 2 ). In use the seat ( 2 ) deforms to reduce the size of the gap ( 24 ) under the weight of a sitter. This deformation thereby provides a more comfortable seat.

1 . An injection moulded one piece plastic chair comprising:
 a seat having a front region and a rear region, a pair of front legs, and a pair of rear legs;   wherein said seat and legs are integrally connected to each other,   the upper portions of said front legs are interconnected by a first rib which projects from the underside of said seat across substantially the width of said seat front region and provides a support for said seat front region and a cross-brace for said front legs; and   the upper portions of said rear legs are connected by a second substantially U-shaped rib which is located below said seat rear region, which forms a cross-brace for said rear legs, which extends across substantially the width of said seat rear region, and which is connected with said seat only adjacent said rear legs, so that a first opening is formed between the underside of said seat and said second rib,   whereby said rear region of said seat can flex toward said second rib under the load of the weight of a sitter.   
     
     
         2 . The chair as claimed in  claim 1  wherein the second rib is shaped to have an increased stiffness relative to a planar rib moulded together with said seat. 
     
     
         3 . The chair as claimed in  claim 2  wherein said second rib has at least one portion of appreciable thickness in a front to rear direction relative to said seat. 
     
     
         4 . The chair as claimed in  claim 3  wherein said second rib is at least partially hollow. 
     
     
         5 . The chair as claimed in  claim 2  wherein said second rib has a cross-sectional shape which is bent or curved or kinked. 
     
     
         6 . The chair as claimed in  claim 1  and having a backrest extending upwardly from said seat rear region. 
     
     
         7 . The chair as claimed in  claim 6  and having a second opening between said backrest and said seat whereby said backrest can flex relative to said seat.