Collapsible chair with adjustable backrest

Abstract

A chair includes a support assembly comprised of a first leg set having two space first leg bars and a second leg set having two space second leg bars that are located between and pivoted to the first leg bars. A backrest has lower ends pivoted to the second leg bars and is thus rotatable with respect to the support assembly to selectively change a tilting angle of the backrest with respect to the support assembly. A tubular slide is movably fit over a free end of each first leg bar and is pivoted to the backrest. The tubular slide has a fastening device to selectively secure the tubular slide with respect to the first leg bar thereby releasably securing the backrest with respect to the support assembly.

1 . A chair comprising: 
 a support assembly comprising: 
 a first leg set comprising two spaced first leg bars;  
 a second leg set comprising two spaced second leg bars which are located between and pivoted to the first leg bars;  
   a backrest having lower ends pivoted to the second leg bars and rotatable with respect to the support assembly to selectively change a tilting angle of the backrest with respect to the support assembly; and    a slide movably fit over and receiving therein a free end of each first leg bar and pivoted to the backrest, the slide further comprising fastening means to selectively secure the slide with respect to the first leg bar thereby releasably securing the backrest with respect to the support assembly.    
     
     
         2 . The chair as claimed in  claim 1  further comprising a constraint element mounted between the free end of the first leg bar and the slide to prevent the slide from sliding off the first leg bar.  
     
     
         3 . The chair as claimed in  claim 1 , wherein the fastening means comprise a friction based fastening device.  
     
     
         4 . A chair comprising: 
 a support assembly comprising: 
 a first leg set comprising two spaced first leg bars;  
 a second leg set comprising two spaced second leg bars which are located between and pivoted to the first leg bars;  
   a backrest having lower ends pivoted to the second leg bars and rotatable with respect to the support assembly to selectively change a tilting angle of the backrest with respect to the support assembly;    a slide movably fit over a free end of each first leg bar and pivoted to the backrest, the slide further comprising fastening means to selectively secure the slide with respect to the first leg bar thereby releasably securing the backrest with respect to the support assembly; and 
 a base on which the support assembly is mounted, the base being partially accommodated in the support assembly and adapted to support the support assembly above a fixture surface, swing arms having opposite ends rotatably mounted to the base and the support assembly to allow for to-and-fro movement of the support assembly and the backrest with respect to the base.  
   
     
     
         5 . The chair as claimed in  claim 4 , wherein the base comprises two inverted U-shaped bar members adapted to be positioned on a fixture surface, each U-shaped bar member having a top section and wherein the support assembly comprises an elongate bar mounted to and extending between the first leg bar and the associated second leg bar at a location below the top section of the corresponding U-shaped member and substantially parallel to the top section, the swing arms being rotatably mounted to the top section and the elongate bar to allow for the to-and-fro movement of the support assembly with respect to the base.  
     
     
         6 . The chair as claimed in  claim 5 , wherein the U-shaped bar member comprises two legs depending from opposite ends of the top section, each leg telescopically receiving an inner leg member that is selectively secured at upper and lower positions to support the support assembly at high and low positions with respect to the fixture surface.  
     
     
         7 . The chair as claimed in  claim 1 , wherein the first leg bars have convex arc configuration whereby a portion thereof functioning as an armrest.  
     
     
         8 . The chair as claimed in  claim 7  further comprising an armrest pad mounted to the armrest.  
     
     
         9 . The chair as claimed in  claim 1  further comprising a seat member made of flexible fabric mounted between the second leg bars.  
     
     
         10 . The chair as claimed in  claim 1 , wherein the backrest comprises two back bars spaced from each other to support a flexible fabric member therebetween as a back support member.  
     
     
         11 . The chair as claimed in  claim 10  further comprising a head pillow mounted to the backrest.  
     
     
         12 . The chair as claimed in  claim 10 , wherein the back bars are tubular and wherein the backrest further comprises a U-shaped top member having limbs telescopically received in the back bars, securing means being provide between the limbs and the back bars to selectively secure the U-shaped top member with respect to the back bars.  
     
     
         13 . The chair as claimed in  claim 12  further comprising a head pillow mounted to the U-shaped top member and partially overlapping the flexible fabric member.  
     
     
         14 . The chair as claimed in  claim 13 , wherein the securing means comprises a spring-biased pin.  
     
     
         15 . The chair as claimed in  claim 1 , wherein each of the first and second leg bars has an end adapted to be positioned on a fixture surface.  
     
     
         16 . The chair as claimed in  claim 15 , wherein the end of each leg bar has an expanded sphere.  
     
     
         17 . A chair comprising: 
 a support assembly comprising: 
 a first leg set comprising two spaced first leg bars;  
 a second leg set comprising two spaced second leg bars which are located between and pivoted to the first leg bars;  
   a backrest having lower ends pivoted to the second leg bars and rotatable with respect to the support assembly to selectively change a tilting angle of the backrest with respect to the support assembly;    a slide movably fit over a free end of each first leg bar and pivoted to the backrest, the slide further comprising fastening means to selectively secure the slide with respect to the first leg bar thereby releasably securing the backrest with respect to the support assembly; and 
 a joint member comprising two spaced lugs receiving each second leg bar therein, a pivot extending through both the lugs and the second leg bar to pivotally connect the joint member to the second leg bar, the joint member comprising a cylindrical projection removably fit into a tubular portion of each lower end of the backrest, releasable securing means securing the cylindrical projection of the joint member to the lower end of the backrest.  
   
     
     
         18 . The chair as claimed in  claim 17 , wherein the securing means comprises a spring-biased pin.  
     
     
         19 . The chair as claimed in  claim 6 , wherein means for selectively securing the inner leg member at upper and lower positions comprises a spring-biased pin.