Folding Chair with Back Angle Adjustment Structure

Abstract

A chair has a backrest assembly, a foot tube assembly, and an armrest assembly. The armrest assembly comprises an armrest slidably connected with an armrest base. The armrest base is operatively connected to an upper portion of the foot tube assembly. A back end of the armrest is operatively hingedly connected to the backrest assembly. An elastic member is operatively connected to the armrest and the armrest base. The elastic member extends in a direction of sliding of the armrest relative to the armrest base. A lock is moveable between an engagement position wherein the armrest is fixed to the armrest base and a disengagement position wherein the armrest is slidable relative to the armrest base under bias from the elastic member. The chair may be foldable.

What is claimed is: 
     
         1 . A chair comprising a backrest assembly, a foot tube assembly, and an armrest assembly, the armrest assembly comprising an armrest slidably connected with an armrest base, the armrest base being operatively connected to an upper portion of the foot tube assembly, a back end of the armrest being operatively hingedly connected to the backrest assembly, the armrest assembly further comprising an elastic member operatively connected to the armrest and the armrest base, the elastic member extending in a direction of sliding of the armrest relative to the armrest base, the armrest assembly further comprising a lock, the lock being moveable between an engagement position wherein the armrest is fixed to the armrest base and a disengagement position wherein the armrest is slidable relative to the armrest base under bias from the elastic member. 
     
     
         2 . The chair according to  claim 1 , wherein one end of the elastic member is operatively connected to the armrest and an opposite end of the elastic member is operatively connected to the armrest base. 
     
     
         3 . The chair according to  claim 1 , wherein the elastic member is one of a spring, an elastic rope, or a gas strut. 
     
     
         4 . The chair according to  claim 1 , wherein the armrest comprises a top panel with opposite side panels defining a hollow interior of the armrest, and an inner tube is disposed within the hollow interior of the arm rest. 
     
     
         5 . The chair according to  claim 4 , wherein the inner tube is slidably arranged with the armrest base. 
     
     
         6 . The chair according to  claim 5 , wherein the inner tube has a long-strip-shaped through hole, the armrest base has a fastener that is fixed in the armrest base and extends into the long-strip-shaped through hole, the fastener of the armrest base is configured to slide in the long-strip-shaped through hole when the armrest slides relative to the armrest base. 
     
     
         7 . The chair according to  claim 6 , wherein one end of the elastic member is operatively connected to the fastener of the armrest base. 
     
     
         8 . The chair according to  claim 7 , wherein the inner tube has a fastener, an opposite end of the elastic member is operatively connected the fastener of the inner tube. 
     
     
         9 . The chair according to  claim 6 , wherein the fastener of the armrest base is one of a pin, bolt, or post. 
     
     
         10 . The chair according to  claim 7 , wherein the fastener of the inner tube is one of a pin, bolt, or post. 
     
     
         11 . The chair according to  claim 1  wherein, when the backrest assembly is moved away from the armrest base, tension in the elastic member increases; and when the backrest assembly is moved toward the armrest base, tension in the elastic member decreases. 
     
     
         12 . The chair according to  claim 1 , wherein the elastic member is a spring, and opposite ends of the spring are operatively connected to the armrest and the armrest base, respectively. 
     
     
         13 . The chair according to  claim 1 , wherein the lock comprises a lever and a clamping block arranged in the armrest base, the lever actuates the clamping block to engage the armrest when the lock is the engagement position, the lever actuates the clamping block to release from the armrest, when the lock is the disengagement position. 
     
     
         14 . The chair according to  claim 5 , wherein the lock comprises a lever and a clamping block arranged in the armrest base, the lever actuates the clamping block to engage the innertube when the lock is the engagement position, the lever actuates the clamping block to release from the innertube, when the lock is the disengagement position. 
     
     
         15 . The chair according to  claim 1 , wherein the backrest assembly is foldable between a folded configuration and an expanded configuration. 
     
     
         16 . The chair according to  claim 1 , wherein the foot tube assembly is foldable between a folded configuration and an expanded configuration.