Abstract:
A portable folding chair suitable for travel and leisure can be used, e.g., in households, outdoors, and in a garden. The folding chair includes a chair support frame, a surface fabric, a backrest, arms, and shoes. The chair support frame includes seating frame tubes, back-rest tubes, arm front support tubes, front support legs, front cross tubes, rear support legs, connection sliding blocks, locking sliding blocks, arm sliding blocks, rear cross tubes, locking fixtures, fixing elements, sliding locating blocks, rotating support blocks, and U-shaped hinging pieces. The front and rear support legs form an inverted V-shaped support structure when unfolded, and are drawn in when folded, because the chair is connected by cross tubes and inverted V-shaped support legs.

Description:
FIELD OF THE INVENTION 
   This invention relates to a portable folding chair and, more particularly, to a portable folding chair that is suitable for travel and leisure and that can be used in a variety of environments including, for example, in households, outdoors, and in a garden. 
   BACKGROUND ART 
   The existing folding chair suitable for travel and leisure mainly has two structures. One uses an assembly-type structure composed of multiple U-shaped rectangular frames, with the chair fabric being stretched tight. This is comfortable for sitting and resting, but has a large volume when folded, and thus is inconvenient for carrying and depositing. The other uses a plurality of crossed supports connected together, and has a small volume when folded, but its arms are soft because the chair fabric is connected to the chair support frame via some fixing points and therefore cannot be easily stretched tight. When a person sits in the chair, the person is likely to sink undesirably, thus causing poor comfort. In addition, the chair body support structure has poor strength and therefore can bear only a relatively small load. Thus, after a period of use or upon bearing a heavy load, the chair surface is likely to tear. 
   SUMMARY OF THE INVENTION 
   The present invention provides a portable folding chair that overcomes the above drawbacks. In one embodiment, the portable folding chair includes a chair support frame, rigid arms, a seating plane, front support legs, and rear support legs. The chair support frame forms an inverted V-shaped support structure when unfolded and is merged together when folded, with front and rear crossed tubes being connected to the front and rear V-shaped support legs, and the back-rest tubes and seating frame tubes being connected to and sleeved over the rear support legs. The entire chair can be folded at once by means of the front and rear crossed tubes, various movable blocks and rotating elements, and occupies a small volume after being folded, and is therefore convenient for carrying. Meanwhile, the chair fabric is sleeved over the seating frame tubes and back-rest tubes, and the fabric is stretched tight naturally by human body&#39;s weight when a person sits on the chair, with the force being distributed uniformly. 
   In one embodiment, the portable folding chair structure includes a chair support frame, a surface fabric, a backrest, arms, seating frame tubes, back-rest tubes, arm front support tubes, front support legs, front cross tubes, rear support legs, connection sliding blocks, locking sliding blocks, arm sliding blocks, rear cross tubes, locking fixtures, fixing elements, sliding locating blocks, rotating support blocks, U-shaped hinging pieces, and plastic shoes. The rear support legs are connected to the front support legs through the rotating support blocks. Each of the seating frame tubes and back-rest tubes are connected to one of the rear support legs through one of the connection sliding blocks, such that they can slide freely along the rear support legs. The middle portion of each of the seating frame tubes is connected to the middle portion of one of the front support legs. The upper end of each of the front cross tubes is fixed to one of the fixing elements of one of the seating frame tubes via one of the U-shaped hinging pieces, and the lower end of each of the front cross tubes is fixed to one of the locking fixtures on one of the front support legs via one of the U-shaped hinging pieces. The upper end of each of the rear cross tubes is fixed to one of the sliding locating blocks on one of the back-rest tubes via one of the U-shaped hinging pieces, and the lower end of each of the rear cross tubes is connected to one of the rear support legs via one of the U-shaped hinging pieces. Both the front support legs and the rear support legs are equipped with plastic shoes. The fabric is fixed to the chair support frame through the seating frame tubes and the back-rest tubes. The lower end of each of the arm front support tubes is connected to one of the locking sliding blocks sleeved on one of the front support legs, and the middle portion of each of the arm front support tubes is connected to one of the fixing elements. The front end of each of the arms is connected to the upper end of one of the arm front support tubes, and the rear end of each of the arms is fixed to the upper portion of one of the front support legs via one of the arm sliding blocks slidably mounted in the sliding groove located under each of the arms. 
   When a person wants to use the portable folding chair of this invention, he can hold the front end of the seating frame tube, and pull the upper end of the back-rest tube toward both sides to bring the front cross and rear cross tubes rotationally open, and to make the rear support leg rotate outwards. At the same time the front support tube of the arm slides downward along the front support leg. When the rotating support block on the rear support leg gets stuck in the front support leg, the support frame is fully opened, and the folding chair is ready for use. To fold the chair, one can fold inward the seating frame tube and back-rest tube to make the arm front support tube slide upward along the front support leg through the arm and the locking sliding block of the front support tube, then push the front end of the arm backward so that the arm slides backward along the arm sliding block located under the arm tube. At the same time, the front and rear cross tubes are folded inward to collapse the support frame into the folded position. Once the chair is folded, the chair may be put into a bag for convenient carrying. 
   Compared with the prior art, the portable folding chair of this invention has the following advantages and characteristics: 
   1. When the support frame is unfolded, it has numerous locking points, and when rotating the fixture and the arm support tube locking element, the support frame has a uniform force distributed all over, with a stable structure; 
   2. The arms can slide backward, and thus the chair can be packed in a small volume; 
   3. The locking of the arm front support tube makes the arms completely fixed, and thus provides good stability; and 
   4. The support frame can be folded and unfolded all at once, and is therefore easy to fold and unfold. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic diagram of the structure of a portable folding chair according to one embodiment of this invention. 
       FIG. 2  is a schematic diagram of the support frame of a portable folding chair according to this invention. 
       FIG. 3  is a schematic diagram of the locking sliding block in a portable folding chair according to this invention. 
       FIG. 4  is a schematic diagram of the locking fixture of a portable folding chair according to this invention. 
       FIG. 5  is a schematic diagram of the connection sliding block of a portable folding chair according to this invention. 
       FIG. 6  is a schematic diagram of the slidable locating block of a portable folding chair according to this invention. 
       FIG. 7  is a schematic diagram of the local amplification of portion I in  FIG. 2 , showing the connection state of the fixture. 
       FIG. 8  is a schematic diagram of the local amplification of portion II in  FIG. 2 , showing the connection state of the slidable locating block. 
       FIG. 9  is a schematic diagram of the local amplification of portion III in  FIG. 2 , showing the connection state of the rotating support block. 
       FIG. 10  is a schematic diagram of the local amplification of portion IV in  FIG. 2 , showing the connection state of the locking sliding block and locking fixture. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In the following discussion, the present invention will be further described in conjunction with the drawings. 
     FIGS. 1 and 2  show a portable folding chair of this invention. The portable folding chair of this invention includes a support frame, chair surface  19 , back-rest tube  1 , arm  2 , seating frame tube  3 , arm front support tube  4 , front support leg  6 , front cross tube  7 , rear support leg  8 , connection sliding block  9 , locking sliding block  10 , arm sliding block  11 , rear cross tube  12 , locking fixture  13 , fixing element  14 , sliding locating block  15 , rotating support block  16 , U-shaped hinging piece  17 , and plastic shoe  18 . 
     FIGS. 3-6  are schematic views of locking sliding block  10 , locking fixture  13 , connection sliding block  9 , and sliding locating block  15 , respectively, in the portable folding chair according to this invention. It can be seen from  FIG. 3 , the main body of locking sliding block  10  is a ring, and the ring is provided with a sliding hole  103 , which is sleeved on the front support leg  6  (see FIGS.  1  and  2 ). At the perimeter of the ring is provided two wings extending in parallel along the radial direction of sliding hole  103 , and the two wings are symmetrically disposed with pivoting holes  101 . Two recesses  102  are correspondingly disposed at the lower edge of the ring of locking sliding block  10 . 
   Referring to  FIG. 4 , the main body of the locking fixture  13  of this invention is a ring, in which is provided a hole  131 , which is sleeved and fixed to the front support leg  6  (see FIGS.  1  and  2 ). Two protrusions  132 , which extend in parallel with the axial direction of the hole  131 , are provided at the two sides of the top of the locking fixture  13 . 
   Referring to  FIG. 5 , the main body of the connection sliding block  9  is a ring, and the ring is disposed with a sliding hole  92 , which is mounted on the rear support leg  8 . Two parallel projections  94  extending along the radial direction of the sliding hole  92  are provided at one end of the perimeter of the ring of connection sliding block  9 . The projections  94  are correspondingly disposed with pivoting holes  93 . Two parallel wings  95  extending along the radial direction of the sliding hole  92  are provided at the other end of the perimeter of the ring of connection sliding block  9 . The wings  95  are correspondingly disposed with pivoting holes  91 . As shown in  FIGS. 1 and 2 , seating frame tube  3  and back-rest tube  1  are respectively connected to the pivoting holes  93 ,  91  of the connection sliding block  9 . 
   Referring to  FIG. 6 , in the middle portion of the sliding locating block  15  is provided sliding hole  152 , and the sliding hole  152  is sleeved on the back-rest tube  1 , which can slide up and down freely. Two parallel wings  154  extending along the radial direction of sliding hole  152  are provided at one end of the sliding locating block  15 , and at the wings are symmetrically provided pivoting holes  153 . At the other end of the sliding locating block  15  is provided an extending wing  155 , which extends along the radial direction of sliding hole  152 . The extending wing  155  is disposed with another pivoting hole  151 . As shown in  FIGS. 1 and 2 , the upper end of the rear cross tube  12  is connected to the pivoting hole  151  on the sliding locating block  15  via a U-shaped hinge  17 . 
     FIGS. 7-10  are the local schematic views of the connection relationships and structures of the fixing element  14 , sliding locating block  15 , connection sliding block  9 , rotating support block  16 , locking sliding block  10 , and locking fixture  13 . 
   Referring to  FIGS. 1 ,  2  and  9 , the rear support leg  8  is connected to the front support leg  6  via a rotating support block  16 . The seating frame tube  3  and back-rest tube  1  are respectively connected to the pivoting holes  93  and  91  of the connection sliding block  9 . The sliding hole  92  of the connection sliding block  9  is sleeved on the rear support leg  8 , and connected to the rear support leg  8  via connection sliding block  9 . The seating frame tube  3  and back-rest tube  1  can slide freely along the rear support leg, and the middle portion of the seating frame tube  3  is connected to the middle portion of the front support leg  6  (see FIG.  7 ). The upper ends of the front cross tubes  7  are fixed to the fixing elements  14  of the seating frame tube  3  respectively via a U-shaped hinging piece  17 , and the lower ends are fixed respectively to the locking fixtures  13  of the two front support legs  6  via a U-shaped hinging piece  17 . The hole  131  on the main body of the locking fixture  13  is sleeved and fixed to the lower portion of the front support leg  6  such that the projections  132  are in an upward orientation, as shown in FIG.  10 . 
   As shown in  FIGS. 1 ,  2  and  8 , the upper ends of the rear cross tubes  12  are connected respectively to the pivoting hole  151  on the sliding locating block  15  via another U-shaped hinging piece  17 . The sliding hole  152  of the sliding locating block  15  is sleeved on the back-rest tube  1  and can slide up and down freely. Another pivoting hole  153  on the sliding locating block  15  is pivoted to the upper end of the front support leg  6 , and the lower ends of the rear cross tubes  12  are connected respectively to the rear support leg  8  via another U-shaped hinging piece  17 . The lower ends of the front support leg  6  and rear support leg  8  are equipped with plastic shoes  18 . The chair surface  19  is fixed to the chair support frame via the seating frame tube  3  and back-rest tube  1 , and the lower end of the arm support tube  4  is connected to the pivoting hole  101  on the locking sliding block  10 . The sliding hole  103  on the locking sliding block  10  is sleeved on the front support leg  6 , and the recess  102  thereon is in a downward orientation. The middle portion of the arm support tube  4  is connected to the fixing element  14  (as shown in FIG.  7 ). The front end of the arm  2  is connected to the upper end of the arm front support tube  4 , and the rear end is connected to the upper portion of the front support leg  6  via the slidable arm sliding block  11  mounted in the sliding groove under the arm  2 . 
   The portable folding chair will be an inverted V-shaped structure when the front and rear support legs are unfolded, and will be drawn in when folded, because the chair is all connected by cross tubes and support legs. The portable folding chair of this invention is a symmetrical structure, and therefore it will be apparent to one skilled in the art that the opposing sides of the chair are symmetrically configured even if that is not explicitly stated herein. 
   To use the portable folding chair of this invention, one can hold the front end of the seating frame tube  3 , and pull the upper end of the back-rest tube  1  toward both sides to bring the front cross tube  7  and rear cross tube  12  rotationally open, and to make the rear support leg  8  rotate outwards. At the same time the front support tube  4  of the arm slides downward along the front support leg  6 . When the rotational support block  16  on the rear support leg  8  gets stuck in the front support leg, as shown in  FIG. 10 , and when the recess  102  is arranged downward and sleeved through the locking sliding block  10  of the front support leg and is fitted tight with the protrusion  132  arranged upward on the locking fixture  13  at the lower portion of the front support leg  6 , the support frame is fully opened, and the folding chair is ready for use. To fold the chair, one can fold inward the seating frame tube  3  and back-rest tube  1  to make the arm front support tube  4  slide upward along the front support leg  6  through the arm  2  and the locking sliding block  10  of the front support tube, then push the front end of the arm backward so that the arm  2  slides backward along the arm sliding block  11  located under the arm  2 . At the same time, the front and rear cross tubes  7 ,  11  are drawn in to fold the support frame. Once the chair is folded, the chair may be put into a bag for convenient carrying. 
   The invention has been described herein in terms of several exemplary embodiments. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention. The embodiments and preferred features described above should be considered exemplary, with the invention being defined by the appended claims and equivalents thereof.