Height-adjustable folding chair

Abstract

A height-adjustable folding chair comprises a first support, a second support, and a seat plate. A middle section of the first support is connected to a middle section of the second support through a hinge shaft, a lower section of the first support and a lower section of the second support each have a bending angle, and two ends of the seat plate are pivotally secured with a first support upper cross rod and a second support upper cross rod respectively. The seat plate has a side A and a side B. When the first support and the second support are unfolded in an X shape, a bent section of the first support and a bent section of the second support are bent facing each other or are bent facing away from each other.

What is claimed is: 
     
         1 . A height-adjustable folding chair, comprising a first support, a second support, and a seat plate, wherein a middle section of the first support is connected to a middle section of the second support through a hinge shaft, a lower section of the first support and a lower section of the second support each have a bending angle, and two ends of the seat plate are pivotally secured with a first support upper cross rod and a second support upper cross rod respectively; the seat plate has a side A and a side B facing away from the side A; and when the first support and the second support are unfolded in an X shape, a bent section of the first support and a bent section of the second support are bent facing each other, in which case the side B of the seat plate faces upwards, or the bent section of the first support and the bent section of the second support are bent facing away from each other, in which case the side A of the seat plate faces upwards. 
     
     
         2 . The height-adjustable folding chair according to  claim 1 , wherein the seat plate is a soft-body seat plate comprising two tubes and a soft connecting body, the two tubes are coupled and fixed to the first support upper cross rod and the second support upper cross rod respectively, and two ends of the soft connecting body are connected to the two tubes respectively. 
     
     
         3 . The height-adjustable folding chair according to  claim 1 , wherein the seat plate is a hinge seat plate comprising a front plate and a rear plate, a front end of the front plate is pivotally secured with the first support upper cross rod, a rear end of the rear plate is pivotally secured with the second support upper cross rod, a rear end of the front plate and a front end of the rear plate have square wave shapes engaging each other, and engaging portions are connected to each other through a transverse hinge shaft. 
     
     
         4 . The height-adjustable folding chair according to  claim 1 , wherein the seat plate is a sliding seat plate which is a rigid plate, the sliding seat plate is provided with a slotted hole at a front side portion for pivotal secure with the first support upper cross rod, allowing the first support upper cross rod to slide within the sliding seat plate, and the sliding seat plate is provided with a round hole at a rear end for pivotal secure with the second support upper cross rod. 
     
     
         5 . The height-adjustable folding chair according to  claim 1 , wherein the first support comprises two parallel first support connecting rods and the first support upper cross rod, the first support connecting rods each comprise a first support first connecting rod and a first support second connecting rod, two ends of the first support upper cross rod are connected to upper ends of the two first support first connecting rods respectively, a lower section of the first support first connecting rod is movably inserted into an upper end of the first support second connecting rod, a pin hole is provided at a side portion of a lower end of the first support first connecting rod, two pin holes are provided at a side portion of an insertion-receiving section of the first support second connecting rod, and relative positions of the first support first connecting rod and the first support second connecting rod are secured by inserting a pin into the corresponding pin holes. 
     
     
         6 . The height-adjustable folding chair according to  claim 1 , wherein the second support comprises two parallel second support connecting rods and the second support upper cross rod, the second support connecting rods each comprise a second support first connecting rod and a second support second connecting rod, two ends of the second support upper cross rod are connected to upper ends of the two second support first connecting rods respectively, a lower section of the second support first connecting rod is movably inserted into an upper end of the second support second connecting rod, a slotted hole is provided at a side portion of an inserted section of the second support first connecting rod, a pin hole is provided at a side portion of an upper end of the second support second connecting rod, and a pin passing through the slotted hole is provided in the pin hole. 
     
     
         7 . The height-adjustable folding chair according to  claim 1 , wherein the second support comprises two second support connecting rods, two fixing sleeves, and one second support upper cross rod, the two second support connecting rods are disposed in parallel, the two fixing sleeves are fixed to two ends of the second support upper cross rod respectively, the two fixing sleeves are slidably sleeved on upper ends of the two second support connecting rods respectively, and a fixing point is provided at the upper end of each of the second support connecting rods to prevent the corresponding fixing sleeve from slipping, thereby ensuring the lowest position of the corresponding fixing sleeve. 
     
     
         8 . The height-adjustable folding chair according to  claim 1 , further comprising a backrest support and a backrest fixing plate, wherein a lower end of the backrest support is pivotally secured with an upper section of the second support, a snap point is provided above a portion of the second support hinged to the backrest support, one end of the backrest fixing plate is pivotally secured with a lower section of the backrest support, and a snap opening fitting with the snap point is provided at the other end of the backrest fixing plate. 
     
     
         9 . The height-adjustable folding chair according to  claim 1 , further comprising an armrest support and a backrest support, wherein a lower end of the armrest support is pivotally secured with an upper end of the first support, an upper end of the backrest support is pivotally secured with an upper end of the armrest support, a snap point is provided at an upper end of the second support, and a snap opening fitting with the snap point is provided at a lower end of the backrest support.