Chair backrest

Abstract

Provided is a two-sectional ergonomic chair backrest comprising a vertical backrest support, an upper back unit releasably secured to the backrest support, a waist unit including a front waist member, an intermediate frame, and a rear plate releasably secured to the backrest support, and a bent, resilient connecting member including a lower portion releasably secured to the waist member and the frame, and an upper portion releasably secured to the backrest support such that in response to the waist of a seated person urged against the waist unit, the connecting member is elastically deformed so as to provide a great degree of comfort to the waist.

1 . A chair backrest comprising: 
 a vertical backrest support;    an upper back unit formed of an elastomeric material and releasably secured to the backrest support;    a waist unit including a front waist member formed of an elastomeric material, an intermediate frame, and a rear plate releasably secured to the backrest support, and    a bent, resilient connecting member including a lower portion releasably secured to the waist member and the frame, and an upper portion releasably secured to the backrest support.    
   
   
       2 . The chair backrest of  claim 1 , wherein the backrest support comprises a plurality of upper hollow locating cylinders, and the back unit comprises a plurality of rear pegs shaped to neatly insert into the locating cylinders for fastening.  
   
   
       3 . The chair backrest of  claim 1 , wherein the frame comprises a plurality of peripheral locating holes, and the plate comprises a plurality of peripheral, hollow locating cylinders shaped to neatly insert into the locating holes for fastening.  
   
   
       4 . The chair backrest of  claim 1 , wherein the upper portion of the connecting member is disposed between the back unit and the backrest support, and the lower portion of the connecting member is disposed between the frame and the plate.