Stackable chair with modular slide-on seat back

Abstract

A stackable chair includes first, second, and third frame members. Each of the first and second frame members forms a front and rear chair leg joined by a seat side rail. The third frame member has opposed side portions respectively joined to the seat side rails, a transverse front nose portion, and a pair of upwardly-extending back stiles. A cushioned and upholstered seat module assembly is attached to the seat side rails. A back module assembly includes a contoured, cushioned, and upholstered back base element having a pair of channels formed therein that are configured and located so as to receive and conceal the stiles when the back module assembly is slid onto the stiles, whereby the back module assembly is attachable to the stiles along the channels. A lower lumbar support element is advantageously attached to the lower portion of the back base element.

1 . A chair, comprising: 
 a first frame member forming a first front chair leg and first rear chair leg joined by a first seat side rail;    a second frame member forming a second front chair leg and a second rear chair leg joined by a second seat side rail;    a third frame member having first and second side portions respectively joined to the first and second seat side rails, a transverse front nose portion, and a pair of upwardly-extending back stiles;    a seat module assembly attached to the first and second seat side rails; and    a back module assembly having a pair of channels configured and located so as to receive the stiles, whereby the back module assembly is attachable to the styles.    
   
   
       2 . The chair of  claim 1 , wherein the back module assembly comprises: 
 a back base element having the channels formed therein and having a lower portion; and    a lower lumbar support element attached to the lower portion of the back base element.    
   
   
       3 . The chair of  claim 2 , wherein the back base element is molded from a rigid plastic material.  
   
   
       4 . The chair of  claim 3 , wherein the back base element has a concave front face.  
   
   
       5 . The chair of  claim 3 , wherein the back base element is formed with an integral structural webbing.  
   
   
       6 . The chair of  claim 4 , wherein the back module further comprises: 
 a main back cushion attached to the front face of the back base element; and    an upper lumbar cushion attached to front face of the back base element between the main back cushion and the lower lumbar support element.    
   
   
       7 . The chair of  claim 1 , wherein the seat module comprises: 
 a rigid seat base;    a lower cushion layer; and    an upper cushion layer bonded to the lower cushion layer.    
   
   
       8 . The chair of  claim 7 , wherein lower cushion layer includes a front edge, and wherein the upper cushion layer includes a nose piece that laps down over the front edge of the lower cushion layer and the transverse front nose portion of the third frame element.  
   
   
       9 . The chair of  claim 1 , further comprising: 
 a front torsion bar connecting the first and second front legs; and    a rear torsion bar connecting the first and second rear legs.    
   
   
       10 . A chair, comprising: 
 a first frame member forming a first front chair leg and first rear chair leg joined by a first seat side rail;    a second frame member forming a second front chair leg and a second rear chair leg joined by a second seat side rail;    a third frame member having first and second side portions respectively joined to the first and second seat side rails, a transverse front nose portion, and a pair of upwardly-extending back stiles;    a seat module assembly attached to the first and second seat side rails; and    a back module assembly, comprising: 
 a back base element having a pair of channels formed therein configured and located so as to receive and conceal the stiles, whereby the back module assembly is attachable to the stiles along the channels, the back base element having a lower portion; and  
 a lower lumbar support element attached to the lower portion of the back base element.  
   
   
   
       11 . The chair of  claim 10 , wherein the back base element is molded from a rigid plastic material, and has a concave front face that includes an integral structural webbing.  
   
   
       12 . The chair of  claim 11 , wherein the back module further comprises: 
 a main back cushion attached to the front face of the back base element; and    an upper lumbar cushion attached to front face of the back base element between the main back cushion and the lower lumbar support element.    
   
   
       13 . The chair of  claim 10 , wherein the seat module comprises: 
 a rigid seat base;    a lower cushion layer; and    an upper cushion layer bonded to the lower cushion layer.    
   
   
       14 . The chair of  claim 13 , wherein lower cushion layer includes a front edge, and wherein the upper cushion layer includes a nose piece that laps down over the front edge of the lower cushion layer and the transverse front nose portion of the third frame element.  
   
   
       15 . The chair of  claim 10 , further comprising: 
 a front torsion bar connecting the first and second front legs; and    a rear torsion bar connecting the first and second rear legs.    
   
   
       16 . A chair back module assembly for attachment to a chair frame having a pair of upstanding stiles, comprising: 
 a back base element having a pair of channels formed therein configured and located so as to receive and conceal the stiles, whereby the back module assembly is attachable to the stiles along the channels, the back base element having a lower portion; and    a lower lumbar support element attached to the lower portion of the back base element.    
   
   
       17 . The chair back module assembly of  claim 16 , wherein the back base element is molded from a rigid plastic material, and has a concave front face that includes an integral structural webbing.  
   
   
       18 . The chair back module assembly of  claim 17 , further comprising: 
 a main back cushion attached to the front face of the back base element; and    an upper lumbar cushion attached to front face of the back base element between the main back cushion and the lower lumbar support element.    
   
   
       19 . The chair back module assembly of  claim 18 , further comprising a fabric covering that covers main back cushion, the upper lumbar cushion, and the lower lumbar support element.  
   
   
       20 . The chair back module assembly of  claim 19 , wherein the fabric covering includes a pair of tack strips including a plurality of tacks that are located and oriented to attach the fabric covering to the back base element.