Patent Publication Number: US-2020288870-A1

Title: Folding chair

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 108108625 filed in Taiwan, R.O.C. on Mar. 14, 2019, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates to folding chairs and, more particularly, to a folding chair not only can be folded to store but can also be unfolded to use. 
     2. Description of the Related Art 
     A conventional folding chair consists of a frame, two legs, a pad and a back rest. The legs movably cross the frame. The pad movably fits to the frame. The back rest is mounted on the top of the frame. Therefore, the legs and the pad are unfolded on one side of the frame such that a sitter can sit on the pad. Alternatively, the legs and the pad can press against each other toward the frame, thereby allowing the folding chair to be folded. 
     However, the conventional folding chair has drawbacks described below. Folding the conventional folding chair involves pressing the legs and the pad against each other toward the frame; as a result, the width of the frame and the width of the pad remain unchanged, regardless of whether the conventional folding chair is folded or unfolded, and thus the conventional folding chair takes up much space and is not portable. Furthermore, after the folding chair has been unfolded, only the bottom of the frame and the legs are in contact with the ground to bear the weight of the folding chair, thereby compromising the stability and load-bearing capability of the folding chair. 
     Therefore, it is imperative to provide a folding chair which can be folded up like an umbrella and thus takes up little space and is portable and can be unfolded to demonstrate high stability and high load-bearing capability. 
     BRIEF SUMMARY OF THE INVENTION 
     In view of the aforesaid drawbacks of the prior art, it is an objective of the present disclosure to provide a folding chair which can be folded up like an umbrella and thus takes up little space and is portable and can be unfolded to demonstrate high stability and high load-bearing capability. 
     In order to achieve the above and other objectives, the present disclosure provides a folding chair, comprising a left frame rod, a right frame rod, a left frame rotating element, a right frame rotating element, a left rear leg sliding element, a right rear leg sliding element, a left rear leg rod, a right rear leg rod, a left rear leg fixing element, a right rear leg fixing element, a left back rest rod, a right back rest rod, a left back rest rod sliding element, a right back rest rod sliding element, a left front leg rod, a right front leg rod, a left front leg terminal, a right front leg terminal, a left connecting rod, a right connecting rod, a left rear leg terminal, a right rear leg terminal, a left handrail rod, a right handrail rod, a left handrail fixing element, a right handrail fixing element, a left handrail supporting rod, a right handrail supporting rod, a left supporting rod sliding element, a right supporting rod sliding element, a left front limiting element, a right front limiting element, a left rear limiting element, a right rear limiting element, a left sliding element, a right sliding element, a first front supporting rod, a second front supporting rod, a first rear supporting rod, a second rear supporting rod, a pad portion and a back rest portion. The left frame rotating element is movably coupled to one end of the left frame rod substantially. The left rear leg sliding element is movably coupled to the other end of the left frame rod. The left rear leg rod is movably, penetratingly disposed at the left rear leg sliding element. The left rear leg fixing element is coupled to one end of the left rear leg rod and movably coupled to left front leg rod. The left back rest rod sliding element movably fits to the left back rest rod. The left front leg rod is movably coupled to the left frame rod. One end of the left front leg rod is movably coupled to the left back rest rod sliding element. The left front leg terminal is movably coupled to the other end of the left front leg rod. One end of the left connecting rod is movably coupled to the left front leg rod. The left rear leg terminal is movably coupled to the other end of the left rear leg rod. One end of the left handrail rod is movably coupled to the left back rest rod. The left frame rotating element is movably disposed at the left handrail supporting rod. The left handrail fixing element is disposed in the vicinity of the other end of the left handrail rod. One end of the left handrail supporting rod is movably coupled to the left handrail fixing element. The left supporting rod sliding element is coupled to the other end of the left handrail supporting rod. The left supporting rod sliding element movably fits to the left front leg rod. The left front limiting element is disposed at the left handrail supporting rod. The left frame rotating element presses against the left front limiting element. The left rear limiting element is disposed at the left rear leg rod. The left sliding element is movably disposed at the left rear leg rod. Two sides of the left sliding element are pivotally connected to one end of the left back rest rod and the other end of the left connecting rod, respectively. The left sliding element presses against the left rear limiting element. The right frame rotating element is movably coupled to one end of the right frame rod substantially. The right rear leg sliding element is movably coupled to the other end of the right frame rod. The right rear leg rod is movably, penetratingly disposed at the right rear leg sliding element. The right rear leg fixing element is coupled to one end of the right rear leg rod and movably coupled to the right front leg rod. The right back rest rod sliding element movably fits to the right back rest rod. The right front leg rod is movably coupled to the right frame rod. One end of the right front leg rod is movably coupled to the right back rest rod sliding element. The right front leg terminal is movably coupled to the other end of the right front leg rod. One end of the right connecting rod is movably coupled to the right front leg rod. The right rear leg terminal is movably coupled to the other end of the right rear leg rod. One end of the right handrail rod is movably coupled to the right back rest rod. The right frame rotating element is movably disposed at the right handrail supporting rod. The right handrail fixing element is disposed in the vicinity of the other end of the right handrail rod. One end of the right handrail supporting rod is movably coupled to the right handrail fixing element. The right supporting rod sliding element is coupled to the other end of the right handrail supporting rod. The right supporting rod sliding element movably fits to the right front leg rod. The right front limiting element is disposed at the right handrail supporting rod. The right frame rotating element presses against the right front limiting element. The right rear limiting element is disposed at the right rear leg rod. The right sliding element is movably disposed at the right rear leg rod. Two sides of the right sliding element are pivotally connected to one end of the right back rest rod and the other end of the right connecting rod, respectively. The right sliding element presses against the right rear limiting element. The first front supporting rod and the second front supporting rod cross each other and are movably coupled together. One end of the first front supporting rod is movably coupled to the left frame rotating element. The other end of the first front supporting rod is movably coupled to the right front leg terminal. One end of the second front supporting rod is movably coupled to the right frame rotating element. The other end of the second front supporting rod is movably coupled to the left front leg terminal. The first rear supporting rod and the second rear supporting rod cross each other and are movably coupled together. One end of the first rear supporting rod is movably coupled to the left back rest rod sliding element. The other end of the first rear supporting rod is movably coupled to the right rear leg terminal. One end of the second rear supporting rod is movably coupled to the right back rest rod sliding element. The other end of the second rear supporting rod is movably coupled to the left rear leg terminal. The pad portion is disposed at the left frame rod and the right frame rod. The back rest portion is disposed at the left back rest rod and the right back rest rod. 
     In an embodiment of the folding chair, the left frame rotating element has a first pivotal connection portion, a first pivotally connecting and straddlingly connecting portion and a first fitting portion. The first pivotally connecting and straddlingly connecting portion is disposed on the top surface of the first pivotal connection portion. The first fitting portion is disposed on one side of the first pivotal connection portion. One end of the first front supporting rod is movably coupled to the first pivotal connection portion. The left frame rod is movably coupled to the first pivotally connecting and straddlingly connecting portion. The left handrail supporting rod is movably, penetratingly disposed at the first fitting portion. 
     In an embodiment of the folding chair, the left rear leg sliding element has a second fitting portion and a second pivotal connection portion. The second pivotal connection portion is disposed on one side of the second fitting portion. The left rear leg rod is movably, penetratingly disposed at the second fitting portion. The other end of the left frame rod is movably coupled to the second pivotal connection portion. 
     In an embodiment of the folding chair, the left rear leg fixing element has a third pivotally connecting and straddlingly connecting portion and a ninth fitting portion. The third pivotally connecting and straddlingly connecting portion is disposed on one side of the ninth fitting portion. The left front leg rod is movably coupled to the third pivotally connecting and straddlingly connecting portion. One end of the left rear leg rod is coupled to the ninth fitting portion. 
     In an embodiment of the folding chair, the left back rest rod sliding element has a third fitting portion, a fifth pivotal connection portion and a sixth pivotal connection portion. The fifth pivotal connection portion is disposed at one end of the third fitting portion. The sixth pivotal connection portion is disposed on one side of the third fitting portion. The left back rest rod is movably, penetratingly disposed at the third fitting portion. One end of the left front leg rod is movably coupled to the fifth pivotal connection portion. One end of the first rear supporting rod is movably coupled to the sixth pivotal connection portion. 
     In an embodiment of the folding chair, the left sliding element has a fourth fitting portion, a seventh pivotal connection portion and an eighth pivotal connection portion. The seventh pivotal connection portion and the eighth pivotal connection portion are disposed on two sides of the fourth fitting portion, respectively. The left rear leg rod is movably, penetratingly disposed at the fourth fitting portion. One end of the left back rest rod is movably coupled to the seventh pivotal connection portion. The other end of the left connecting rod is movably coupled to the eighth pivotal connection portion. 
     In an embodiment of the folding chair, the right frame rotating element has a ninth pivotal connection portion, a second pivotally connecting and straddlingly connecting portion and a fifth fitting portion. The second pivotally connecting and straddlingly connecting portion is disposed on the top surface of the ninth pivotal connection portion. The fifth fitting portion is disposed on one side of the ninth pivotal connection portion. One end of the second front supporting rod is movably coupled to the ninth pivotal connection portion. The right frame rod is movably coupled to the second pivotally connecting and straddlingly connecting portion. The right handrail supporting rod is movably, penetratingly disposed at the fifth fitting portion. 
     In an embodiment of the folding chair, the right rear leg sliding element has a sixth fitting portion and a tenth pivotal connection portion. The tenth pivotal connection portion is disposed on one side of the sixth fitting portion. The right rear leg rod is movably, penetratingly disposed at the sixth fitting portion. The other end of the right frame rod is movably coupled to the tenth pivotal connection portion. 
     In an embodiment of the folding chair, the right rear leg fixing element has a fourth pivotally connecting and straddlingly connecting portion and a tenth fitting portion. The fourth pivotally connecting and straddlingly connecting portion is disposed on one side of the tenth fitting portion. The right front leg rod is movably coupled to the fourth pivotally connecting and straddlingly connecting portion. One end of the right rear leg rod is coupled to the tenth fitting portion. 
     In an embodiment of the folding chair, the right back rest rod sliding element has a seventh fitting portion, a thirteenth pivotal connection portion and a fourteenth pivotal connection portion. The thirteenth pivotal connection portion is disposed at one end of the seventh fitting portion. The fourteenth pivotal connection portion is disposed on one side of the seventh fitting portion. The right back rest rod is movably, penetratingly disposed at the seventh fitting portion. One end of the right front leg rod is movably coupled to the thirteenth pivotal connection portion. One end of the second rear supporting rod is movably coupled to the fourteenth pivotal connection portion. 
     In an embodiment of the folding chair, the right sliding element has an eighth fitting portion, a fifteenth pivotal connection portion and a sixteenth pivotal connection portion. The fifteenth pivotal connection portion and the sixteenth pivotal connection portion are disposed on two sides of the eighth fitting portion, respectively. The right rear leg rod is movably, penetratingly disposed at the eighth fitting portion. One end of the right back rest rod is movably coupled to the fifteenth pivotal connection portion. The other end of the right connecting rod is movably coupled to the sixteenth pivotal connection portion. 
     In an embodiment of the folding chair, the folding chair further comprises a left connecting element and a right connecting element. The left connecting element is disposed at the left frame rod. The left connecting element movably fits to the left front limiting element. The right connecting element is disposed at the right frame rod. The right connecting element movably fits to the right front limiting element. 
     Therefore, the folding chair of the present disclosure can be folded up like an umbrella and thus takes up little space and is portable and can be unfolded to demonstrate high stability and high load-bearing capability. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a folding chair unfolded according to the present disclosure. 
         FIG. 2  is a schematic view of the folding chair unfolded according to the present disclosure, omitting a pad portion and a back rest portion. 
         FIG. 3  is a schematic view of the folding chair folded according to the present disclosure, omitting a pad portion and a back rest portion. 
         FIG. 4  is another schematic view of the folding chair folded according to the present disclosure, omitting a pad portion and a back rest portion. 
     
    
    
     DETAILED DESCRIPTION OF THE INVETION 
     Objectives, features, and advantages of the present disclosure are hereunder illustrated with specific embodiments, depicted with drawings, and described below. 
     Referring to  FIG. 1  through  FIG. 4 , the present disclosure provides a folding chair comprising a left frame rod  100 , a right frame rod  200 , a left frame rotating element  101 , a right frame rotating element  201 , a left rear leg sliding element  102 , a right rear leg sliding element  202 , a left rear leg rod  103 , a right rear leg rod  203 , a left rear leg fixing element  104 , a right rear leg fixing element  204 , a left back rest rod  105 , a right back rest rod  205 , a left back rest rod sliding element  106 , a right back rest rod sliding element  206 , a left front leg rod  107 , a right front leg rod  207 , a left front leg terminal  108 , a right front leg terminal  208 , a left connecting rod  109 , a right connecting rod  209 , a left rear leg terminal  110 , a right rear leg terminal  210 , a left handrail rod  111 , a right handrail rod  211 , a left handrail fixing element  112 , a right handrail fixing element  212 , a left handrail supporting rod  113 , a right handrail supporting rod  213 , a left supporting rod sliding element  114 , a right supporting rod sliding element  214 , a left front limiting element  115 , a right front limiting element  215 , a left rear limiting element  116 , a right rear limiting element  216 , a left sliding element  117 , a right sliding element  217 , a first front supporting rod  300 , a second front supporting rod  301 , a first rear supporting rod  400 , a second rear supporting rod  401 , a pad portion  500  and a back rest portion  501 . 
     The left frame rotating element  101  is movably coupled to one end of the left frame rod  100  substantially. The left rear leg sliding element  102  is movably coupled to the other end of the left frame rod  100 . The left rear leg rod  103  is movably, penetratingly disposed at the left rear leg sliding element  102 . The left rear leg fixing element  104  is coupled to one end of the left rear leg rod  103  and movably coupled to left front leg rod  107 . The left back rest rod sliding element  106  movably fits to the left back rest rod  105 . The left front leg rod  107  is movably coupled to the left frame rod  100 . One end of the left front leg rod  107  is movably coupled to the left back rest rod sliding element  106 . The left front leg terminal  108  is movably coupled to the other end of the left front leg rod  107 . One end of the left connecting rod  109  is movably coupled to the left front leg rod  107 . The left rear leg terminal  110  is movably coupled to the other end of the left rear leg rod  103 . One end of the left handrail rod  111  is movably coupled to the left back rest rod  105 . The left frame rotating element  101  is movably disposed at the left handrail supporting rod  113 . The left handrail fixing element  112  is disposed in the vicinity of the other end of the left handrail rod  111 . One end of the left handrail supporting rod  113  is movably coupled to the left handrail fixing element  112 . The left supporting rod sliding element  114  is coupled to the other end of the left handrail supporting rod  113 . The left supporting rod sliding element  114  movably fits to the left front leg rod  107 . The left front limiting element  115  is disposed at the left handrail supporting rod  113 . The left frame rotating element  101  presses against the left front limiting element  115 . The left rear limiting element  116  is disposed at the left rear leg rod  103 . The left sliding element  117  is movably disposed at the left rear leg rod  103 . Two sides of the left sliding element  117  are pivotally connected to one end of the left back rest rod  105  and the other end of the left connecting rod  109 , respectively. The left sliding element  117  presses against the left rear limiting element  116 . 
     The right frame rotating element  201  is movably coupled to one end of the right frame rod  200  substantially. The right rear leg sliding element  202  is movably coupled to the other end of the right frame rod  200 . The right rear leg rod  203  is movably, penetratingly disposed at the right rear leg sliding element  202 . The right rear leg fixing element  204  is coupled to one end of the right rear leg rod  203  and movably coupled to right front leg rod  207 . The right back rest rod sliding element  206  movably fits to the right back rest rod  205 . One end of the right front leg rod  207  is movably coupled to the right back rest rod sliding element  206 . The right front leg rod  207  is movably coupled to the right frame rod  200 . The right front leg terminal  208  is movably coupled to the other end of the right front leg rod  207 . One end of the right connecting rod  209  is movably coupled to the right front leg rod  207 . The right rear leg terminal  210  is movably coupled to the other end of the right rear leg rod  203 . One end of the right handrail rod  211  is movably coupled to the right back rest rod  205 . The right frame rotating element  201  is movably disposed at the right handrail supporting rod  213 . The right handrail fixing element  212  is disposed in the vicinity of the other end of the right handrail rod  211 . One end of the right handrail supporting rod  213  is movably coupled to the right handrail fixing element  212 . The right supporting rod sliding element  214  is coupled to the other end of the right handrail supporting rod  213 . The right supporting rod sliding element  214  movably fits to the right front leg rod  207 . The right front limiting element  215  is disposed at the right handrail supporting rod  213 . The right frame rotating element  201  presses against the right front limiting element  215 . The right rear limiting element  216  is disposed at the right rear leg rod  203 . The right sliding element  217  is movably disposed at the right rear leg rod  203 , and Two sides of the right sliding element  217  are pivotally connected to one end of the right back rest rod  205  and the other end of the right connecting rod  209 , respectively. The right sliding element  217  presses against the right rear limiting element  216 . 
     The first front supporting rod  300  and the second front supporting rod  301  cross each other and are movably coupled together. One end of the first front supporting rod  300  is movably coupled to the left frame rotating element  101 . The other end of the first front supporting rod  300  is movably coupled to the right front leg terminal  208 . One end of the second front supporting rod  301  is movably coupled to the right frame rotating element  201 . The other end of the second front supporting rod  301  is movably coupled to the left front leg terminal  108 . The first rear supporting rod  400  and the second rear supporting rod  401  cross each other and are movably coupled together. One end of the first rear supporting rod  400  is movably coupled to the left back rest rod sliding element  106 . The other end of the first rear supporting rod  400  is movably coupled to the right rear leg terminal  210 . One end of the second rear supporting rod  401  is movably coupled to the right back rest rod sliding element  206 . The other end of the second rear supporting rod  401  is movably coupled to the left rear leg terminal  110 . 
     The pad portion  500  is disposed at the left frame rod  100  and the right frame rod  200 . The back rest portion  501  is disposed at the left back rest rod  105  and the right back rest rod  205 . The back rest portion  501  is connected to the pad portion  500 . The pad portion  500  and the back rest portion  501  is made of a soft material, such as fabric or plastic. Therefore, a user can sit on the pad portion  500  with his back pressing against the back rest portion  501  to enhance user experience, as shown in  FIG. 1 . 
     Referring to  FIG. 2  through  FIG. 4 , to fold the folding chair, the user grips one end of the left back rest rod  105  (or the right back rest rod  205 ) and one end of the left frame rod  100  (or the right frame rod  200 ), moves the left frame rod  100  toward the left back rest rod  105  such that the left frame rod  100  moves out of the left frame rotating element  101  and rotates relative to the left frame rotating element  101 , allowing the left frame rod  100  to rotate relative to the left front leg rod  107  and thus allowing the left front leg rod  107  to drive the movement of the left sliding element  117 . Afterward, owing to the left sliding element  117 , the left back rest rod  105  and the left connecting rod  109  move toward the left rear leg rod  103  such that the left rear leg rod  103  moves toward the left front leg rod  107 . Hence, the left frame rotating element  101  moves away from the left front limiting element  115  to thereby cause the separation of the left connecting element  118  and the left front limiting element  115 . Hence, the first front supporting rod  300  drives the right front leg terminal  208  to move toward the left front leg terminal  108 , causes the left rear leg sliding element  102  to slide the left rear leg fixing element  104  relative to the left rear leg rod  103 , and causes the left frame rotating element  101  to drive the left handrail supporting rod  113  to move up because of the left supporting rod sliding element  114 . While the left handrail supporting rod  113  is moving up, the left handrail rod  111  moves toward the left back rest rod  105  because of the left handrail fixing element  112 . The movement of the left front leg rod  107  causes the left back rest rod sliding element  106  to move up relative to the left back rest rod  105 . The upward movement of the left back rest rod sliding element  106  causes the first rear supporting rod  400  and the right rear leg terminal  210  to move toward the left back rest rod  105 . While the aforesaid events are in progress, the right frame rod  200  moves toward the right back rest rod  205  such that the right frame rod  200  moves out of the right frame rotating element  201  and rotates relative to the right frame rotating element  201 , not only causing the right frame rod  200  to rotate relative to the right front leg rod  207 , but also causing the right front leg rod  207  to drive the right sliding element  217 . Furthermore, owing to the right sliding element  217 , the right back rest rod  205  and the right connecting rod  209  move toward the right rear leg rod  203 , causing the right rear leg rod  203  to move toward the right front leg rod  207 . In addition, the right frame rotating element  201  moves away from the right front limiting element  215  to thereby cause the separation of the right connecting element  218  and the right front limiting element  215  such that the second front supporting rod  301  drives the left front leg terminal  108  to move toward the right front leg terminal  208 , cause the right rear leg sliding element  202  to slide away from the right rear leg fixing element  204  relative to the right rear leg rod  203 , and cause the right frame rotating element  201  to drive the right handrail supporting rod  213  to move up because of the right supporting rod sliding element  214 . While the right handrail supporting rod  213  is moving up, the right handrail rod  211  moves toward the right back rest rod  205  because of the right handrail fixing element  212 . The movement of the right front leg rod  207  causes the right back rest rod sliding element  206  to move up relative to the right back rest rod  205 . The upward movement of the right back rest rod sliding element  206  causes the second rear supporting rod  401  and the left rear leg terminal  110  to move toward the right back rest rod  205 . Therefore, the folding chair can be folded up like an umbrella and thus takes up little space and is portable. 
     Regardless of whether the folding chair is folded or unfolded, the left front leg terminal  108 , the left rear leg terminal  110 , the right front leg terminal  208  and the right rear leg terminal  201  provide protection to the left front leg rod  107 , the second front supporting rod  301 , the left rear leg rod  103 , the second rear supporting rod  401 , the right front leg rod  207 , the first front supporting rod  300 , the right rear leg rod  203  and the first rear supporting rod  400 , respectively. Furthermore, they are prevented from coming into direct contact with the ground to otherwise get damaged, and their movement is insusceptible to skidding, thereby allowing the folding chair to demonstrate high stability and high load-bearing capability. 
     In an embodiment of the present disclosure, as shown in  FIG. 2  through  FIG. 4 , the left frame rotating element  101  has a first pivotal connection portion  1011 , a first pivotally connecting and straddlingly connecting portion  1012  and a first fitting portion  1013 . The first pivotally connecting and straddlingly connecting portion  1012  is disposed on the top surface of the first pivotal connection portion  1011 . The first fitting portion  1013  is disposed on one side of the first pivotal connection portion  1011 . One end of the first front supporting rod  300  is movably coupled to the first pivotal connection portion  1011 . The left frame rod  100  is movably coupled to the first pivotally connecting and straddlingly connecting portion  1012 . The left handrail supporting rod  113  is movably, penetratingly disposed at the first fitting portion  1013 . Therefore, to unfold the folding chair, the left frame rod  100  moves into the first pivotally connecting and straddlingly connecting portion  1012  to fit thereto, and the first front supporting rod  300  is driven by the first pivotal connection portion  1011  of the left frame rotating element  101 , not only allowing the left frame rotating element  101  to drive the first front supporting rod  300  easily, but also allowing the left frame rod  100  and the first front supporting rod  300  to have high stability and high load-bearing capability after the folding chair has been unfolded. 
     In an embodiment of the present disclosure, as shown in  FIG. 2  through  FIG. 4 , the left rear leg sliding element  102  has a second fitting portion  1021  and a second pivotal connection portion  1022 . The second pivotal connection portion  1022  is disposed on one side of the second fitting portion  1021 . The left rear leg rod  103  is movably, penetratingly disposed at the second fitting portion  1021 . The other end of the left frame rod  100  is movably coupled to the second pivotal connection portion  1022 . Therefore, regardless of whether the folding chair is folded or unfolded, the left rear leg sliding element  102  slides down or slides up relative to the left rear leg rod  103  because of the second fitting portion  1021 , whereas the left frame rod  100  moves away from or moves into the first pivotally connecting and straddlingly connecting portion  1012  because of the second pivotal connection portion  1022 . Therefore, not only does the left rear leg sliding element  102  move smoothly, but the left frame rod  100  also has high stability and high load-bearing capability after the folding chair has been unfolded. 
     In an embodiment of the present disclosure, as shown in  FIG. 2  through  FIG. 4 , the left rear leg fixing element  104  has a third pivotally connecting and straddlingly connecting portion  1041  and a ninth fitting portion  1042 . The third pivotally connecting and straddlingly connecting portion  1041  is disposed on one side of the ninth fitting portion  1042 . The middle of the left front leg rod  107  is movably coupled to the third pivotally connecting and straddlingly connecting portion  1041 . One end of the left rear leg rod  103  is coupled to the ninth fitting portion  1042 . Therefore, regardless of whether the folding chair is folded or unfolded, the left rear leg rod  103  moves toward the left front leg rod  107  or moves away from the left front leg rod  107  because of the ninth fitting portion  1042 , and the left front leg rod  107  moves toward the left rear leg rod  103  or moves away from the left rear leg rod  103  because of the third pivotally connecting and straddlingly connecting portion  1041 , not only allowing the left rear leg rod  103  and the left front leg rod  107  to move smoothly, but also allowing the left rear leg rod  103  and the left front leg rod  107  to have high stability and high load-bearing capability after the folding chair has been unfolded. 
     In an embodiment of the present disclosure, as shown in  FIG. 2  through  FIG. 4 , the left back rest rod sliding element  106  has a third fitting portion  1061 , a fifth pivotal connection portion  1062  and a sixth pivotal connection portion  1063 . The fifth pivotal connection portion  1062  is disposed at one end of the third fitting portion  1061 . The sixth pivotal connection portion  1063  is disposed on one side of the third fitting portion  1061 . The left back rest rod  105  is movably, penetratingly disposed at the third fitting portion  1061 . The left front leg rod  107  has one end movably coupled to the fifth pivotal connection portion  1062 . The first rear supporting rod  400  has one end movably coupled to the sixth pivotal connection portion  1063 . Therefore, regardless of whether the folding chair is folded or unfolded, the left back rest rod sliding element  106  slides down or slides up relative to the left back rest rod  105  because of the third fitting portion  1061 , allowing the left front leg rod  107  to move toward the left rear leg rod  103  or move away from the left rear leg rod  103  because of the coordination of the fifth pivotal connection portion  1062  and the sixth pivotal connection portion  1063 , allowing the first rear supporting rod  400  to move toward the left back rest rod  105  or move away from the left back rest rod  105 . Therefore, not only does the left back rest rod sliding element  106  move smoothly, but the left back rest rod  105 , the left front leg rod  107  and the first rear supporting rod  400  also have high stability and high load-bearing capability after the folding chair has been unfolded. 
     In an embodiment of the present disclosure, as shown in  FIG. 2  through  FIG. 4 , the left sliding element  117  has a fourth fitting portion  1171 , a seventh pivotal connection portion  1172  and an eighth pivotal connection portion  1173 , The seventh pivotal connection portion  1172  and the eighth pivotal connection portion  1173  are disposed on two sides of the fourth fitting portion  1171 , respectively. The left rear leg rod  103  is movably, penetratingly disposed at the fourth fitting portion  1171 . The left back rest rod  105  has one end movably coupled to the seventh pivotal connection portion  1172 . The other end of the left connecting rod  109  is movably coupled to the eighth pivotal connection portion  1173 . Therefore, the left sliding element  117  slides relative to the left rear leg rod  103  because of the fourth fitting portion  1171 , whereas the left back rest rod  105  and the left connecting rod  109  move toward the left rear leg rod  103  because of the coordination of the seventh pivotal connection portion  1172  and the eighth pivotal connection portion  1173 . Therefore, not only do the left back rest rod  105  and the left connecting rod  109  move smoothly, but the left back rest rod  105  and the left connecting rod  109  also have high stability and high load-bearing capability after the folding chair has been unfolded. 
     In an embodiment of the present disclosure, as shown in  FIG. 2  through  FIG. 4 , the right frame rotating element  201  has a ninth pivotal connection portion  2011 , a second pivotally connecting and straddlingly connecting portion  2012  and a fifth fitting portion  2013 . The second pivotally connecting and straddlingly connecting portion  2012  is disposed on the top surface of the ninth pivotal connection portion  2011 . The fifth fitting portion  2013  is disposed on one side of the ninth pivotal connection portion  2011 . One end of the second front supporting rod  301  is movably coupled to the ninth pivotal connection portion  2011 . The right frame rod  200  is movably coupled to the second pivotally connecting and straddlingly connecting portion  2012 . The right handrail supporting rod  213  is movably, penetratingly disposed at the fifth fitting portion  2013 . Therefore, to unfold the folding chair, the right frame rod  200  moves into the second pivotally connecting and straddlingly connecting portion  2012  to fit thereto, whereas the ninth pivotal connection portion  2011  of the right frame rotating element  201  drives the second front supporting rod  301 , not only allowing the right frame rotating element  201  to drive the second front supporting rod  301  easily, but also allowing the right frame rod  200  and the second front supporting rod  301  to have high stability and high load-bearing capability after the folding chair has been unfolded. 
     In an embodiment of the present disclosure, as shown in  FIG. 2  through  FIG. 4 , the right rear leg sliding element  202  has a sixth fitting portion  2021  and a tenth pivotal connection portion  2022 . The tenth pivotal connection portion  2022  is disposed on one side of the sixth fitting portion  2021 . The right rear leg rod  203  is movably, penetratingly disposed at the sixth fitting portion  2021 . The other end of the right frame rod  200  is movably coupled to the tenth pivotal connection portion  2022 . Therefore, when the folding chair is folded or unfolded, the right rear leg sliding element  202  slides down or slides up along the right rear leg rod  203  because of the sixth fitting portion  2021 , whereas the right frame rod  200  moves away from or moves into the second pivotally connecting and straddlingly connecting portion  2012  because of the tenth pivotal connection portion  2022 . Therefore, not only does the right rear leg sliding element  202  move smoothly, but the right frame rod  200  also has high stability and high load-bearing capability after the folding chair has been unfolded. 
     In an embodiment of the present disclosure, as shown in  FIG. 2  through  FIG. 4 , the right rear leg fixing element  204  has a fourth pivotally connecting, a straddlingly connecting portion  2041  and a tenth fitting portion  2042 . The fourth pivotally connecting and straddlingly connecting portion  2041  is disposed on one side of the tenth fitting portion  2042 . The middle of the right front leg rod  207  is movably coupled to the fourth pivotally connecting and straddlingly connecting portion  2041 . One end of the right rear leg rod  203  is coupled to the tenth fitting portion  2042 . Therefore, when the folding chair is folded or unfolded, the right rear leg rod  203  moves toward the right front leg rod  207  or moves away from the right front leg rod  207  because of the tenth fitting portion  2042 , whereas the right front leg rod  207  moves toward the right rear leg rod  203  or moves away from the right rear leg rod  203  because of the fourth pivotally connecting and straddlingly connecting portion  2041 , thereby not only allowing the right rear leg rod  203  and the right front leg rod  207  to move smoothly, but also allowing the right rear leg rod  203  and the right front leg rod  207  to have high stability and high load-bearing capability after the folding chair has been unfolded. 
     In an embodiment of the present disclosure, as shown in  FIG. 2  through  FIG. 4 , the right back rest rod sliding element  206  has a seventh fitting portion  2061 , a thirteenth pivotal connection portion  2062  and a fourteenth pivotal connection portion  2063 . The thirteenth pivotal connection portion  2062  is disposed at one end of the seventh fitting portion  2061 . The fourteenth pivotal connection portion  2063  is disposed on one side of the seventh fitting portion  2061 . The right back rest rod  205  is movably, penetratingly disposed at the seventh fitting portion  2061 . The right front leg rod  207  has one end movably coupled to the thirteenth pivotal connection portion  2062 . The second rear supporting rod  401  has one end movably coupled to the fourteenth pivotal connection portion  2063 . Therefore, when the folding chair is folded or unfolded, the right back rest rod sliding element  206  slides up or slides down relative to the right back rest rod  205  because of the seventh fitting portion  2061  to thereby allow the right front leg rod  207  to move toward the right rear leg rod  203  or move away from the right rear leg rod  203  because of the coordination of the thirteenth pivotal connection portion  2062  and the fourteenth pivotal connection portion  2063 , and allow the second rear supporting rod  401  to move toward the right back rest rod  205  or move away from the right back rest rod  205  because of the coordination of the thirteenth pivotal connection portion  2062  and the fourteenth pivotal connection portion  2063 . Therefore, not only does the right back rest rod sliding element  206  move smoothly, but the right back rest rod  205 , the right front leg rod  207  and the second rear supporting rod  401  also have high stability and high load-bearing capability after the folding chair has been unfolded. 
     In an embodiment of the present disclosure, as shown in  FIG. 2  through  FIG. 4 , the right sliding element  217  has an eighth fitting portion  2171 , a fifteenth pivotal connection portion  2172  and a sixteenth pivotal connection portion  2173 . The fifteenth pivotal connection portion  2172  and the sixteenth pivotal connection portion  2173  are disposed on two sides of the eighth fitting portion  2171 , respectively, the right rear leg rod  103  is movably, penetratingly disposed at the eighth fitting portion  2171 . The right back rest rod  205  has one end movably coupled to the fifteenth pivotal connection portion  2172 . The other end of the right connecting rod  209  is movably coupled to the sixteenth pivotal connection portion  2173 . Therefore, the right sliding element  217  slides relative to the right rear leg rod  203  because of the eighth fitting portion  2171 , whereas the right back rest rod  205  and the right connecting rod  209  move toward the right rear leg rod  203  because of the coordination of the fifteenth pivotal connection portion  2172  and the sixteenth pivotal connection portion  2173 . Therefore, not only do the right back rest rod  205  and the right connecting rod  209  move smoothly, but the right back rest rod  205  and the right connecting rod  209  also have high stability and high load-bearing capability after the folding chair has been unfolded. 
     In an embodiment of the present disclosure, as shown in  FIG. 2  through  FIG. 4 , the folding chair further comprises a left connecting element  118  and a right connecting element  218 . The left connecting element  118  is disposed at the left frame rod  100 . The left connecting element  118  and the left front limiting element  115  are connected when the folding chair is unfolded but separated when the folding chair is folded. The right connecting element  218  is disposed at the right frame rod  200 . The right connecting element  218  and the right front limiting element  215  are connected when the folding chair is unfolded but separated when the folding chair is folded. Therefore, the left connecting element  118  and the right connecting element  218  have high stability and high load-bearing capability when the folding chair is unfolded. 
     While the present disclosure has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the present disclosure set forth in the claims.