Folding chair

Abstract

A folding chair comprises a seat frame, a front leg bracket and a rear leg bracket, wherein the seat frame comprises at least two support tubes, and the front leg bracket and the rear leg bracket are articulated crosswise to form a foldable support structure. The rear leg bracket and the front leg bracket each have two upper ends corresponding to the two support tubes. The two upper ends of the rear leg bracket are pivoted to the two support tubes respectively. The two upper ends of the front leg bracket are slidably connected to the two support tubes respectively, are limited to first positions of the two support tubes when the foldable support structure is in an unfolded state, and to slide along the two support tubes away from the upper ends of the rear leg bracket when the foldable support structure in the unfolded state is gradually folded.

What is claimed is: 
     
         1 . A folding chair, comprising a seat frame, a front leg bracket and a rear leg bracket, wherein the seat frame comprises at least two support tubes which are located on two sides in parallel, the front leg bracket and the rear leg bracket are articulated crosswise to form a foldable support structure for supporting the seat frame, the rear leg bracket and the front leg bracket each have two upper ends corresponding to the two support tubes, the two upper ends of the rear leg bracket are pivoted to the two support tubes respectively, and the two upper ends of the front leg bracket are slidably connected to the two support tubes respectively, and are arranged to be limited to first positions of the two support tubes when the foldable support structure is in an unfolded state, and to slide away from the upper ends of the rear leg bracket along the two support tubes from the first positions when the foldable support structure changes from the unfolded state to a folded state. 
     
     
         2 . The folding chair according to  claim 1 , wherein the two upper ends of the front leg bracket are pivoted to slide-positioning components respectively, each said slide-positioning component comprises a connecting part to be in sliding fit with the corresponding support tube and a limiting part for limiting the connecting part to the first position of the corresponding support tube, and each said support tube is provided at the first position with a limited part for matching with the limiting part of the corresponding slide-positioning component. 
     
     
         3 . The folding chair according to  claim 2 , wherein the connecting part of each said slide-positioning component is a casing tube part, the limiting part of each said slide-positioning component is a protrusion, and the limited parts of the two support tubes are depressions matched with the protrusion. 
     
     
         4 . The folding chair according to  claim 3 , wherein each said slide-positioning component also comprises an operation part for clamping the protrusions  42  into the depressions to achieve limitation or to disengage the protrusions  42  from the pressions to release the limitation. 
     
     
         5 . The folding chair according to  claim 4 , wherein each said slide-positioning component also comprises an elastic member which provides an elastic force to drive the protrusion into the depression. 
     
     
         6 . The folding chair according to  claim 5 , wherein each said casing tube part comprises a first sleeving hole allowing the support tube to be sleeved therein, and a mounting hole perpendicular to and communicated with the first sleeving hole; and the operation part is inserted into the mounting hole, the operation part comprises a second sleeving hole allowing the support tube to be sleeved therein and slightly larger than an outer diameter of the support tube, the second sleeving hole is provided with the protrusion on a side in a moving direction of the operation part, and the elastic member acts on the operation part and the casing tube part such that the protrusion of the operation part moves towards the depression of the support tube in the mounting hole of the casing tube part. 
     
     
         7 . The folding chair according to  claim 6 , wherein an inner diameter of the first sleeving hole is equivalent to an outer diameter of the support tube. 
     
     
         8 . The folding chair according to  claim 6 , wherein the elastic member is a spring, and a joint between the operation part and the spring comprises a limiting boss for limiting a position of the spring. 
     
     
         9 . The folding chair according to  claim 2 , wherein each said support tube is provided with an auxiliary limiting device for limiting the slide-positioning component at a position corresponding to the slide-positioning component at the first position. 
     
     
         10 . The folding chair according to  claim 9 , wherein each said auxiliary limiting device comprises a third sleeving hole allowing the support tube to be sleeved therein and at least one fixing hole perpendicular to and communicated with the third sleeving hole, and the auxiliary limiting device is fixed on the support tube through the fixing hole.