Triple-crossed horizontal folding cart

A triple-crossed horizontal folding cart, comprising:

• a cart frame;
• wherein the cart frame comprises a frame body formed by a front wall, a rear wall, and two symmetrical side walls;
• a chassis disposed at a bottom of the frame body;
• wherein a left end and a right end of the front wall being each provided with a wheel;
• wherein a left end and a right end of the rear wall being each provided with a wheel;
• wherein a front end and a rear end of the chassis are rotatably connected to the front wall and the rear wall respectively;
• wherein each of the side walls comprises a front cross tube, a middle cross tube and a rear cross tube all of which are rotatably connected in sequence;
• wherein a first and second straight tubes of each said cross tube are rotatably connected;
• wherein an upper and lower sides of the front cross tube are rotatably connected to the front wall and the chassis respectively;
• wherein an upper and lower sides of the rear cross tube are rotatably connected to the rear wall and the chassis respectively;
• wherein the first straight tube of the front cross tube or the rear cross tube is a
• a) long tube, or
• b) short tube, and is connected to the chassis;
• the second straight tube of the front cross tube or the rear cross tube is a short tube, and is connected to the front wall or the rear wall;
• wherein an upper section of the long tube is riveted to the short tube;
• wherein each said bottom frame comprises a long horizontal rod, a short horizontal rod and two side rods, and front and rear ends of each said side rod are connected to the front wall or the rear wall, and one said bottom frame connector respectively;
• wherein two ends of the long horizontal rod are fixed to sides, close to the front wall or the rear wall, of the two side rods respectively, and two ends of the short horizontal rod are fixed to sides, close to the bottom frame connectors, of the two side rods respectively;
• wherein two ends of a connecting rod are fixed to a middle of the long horizontal rod and a middle of the short horizontal rod respectively;
• wherein each said bottom frame connector comprises a U-shaped connecting piece which is open downward, and a rivet, one side of the U-shaped connecting piece is disposed around and fixed at ends of the side rods of one said bottom frame, through holes in a left-right direction are formed in two symmetrical walls on the other side of the U-shaped connecting piece, shaft sleeves are disposed on lower surfaces of ends of the side rods of the other bottom frame, and the rivet penetrates through the through holes and the shaft sleeves to rotatably connect the U-shaped connecting piece and the other bottom frame;
• and
• when the short horizontal rod is pulled upward or downward, the ends of the side rods of the other bottom frame are separated from or inlaid in an opening of the U-shaped connecting piece, and the two bottom frames are folded or unfolded.