Dual-use bleacher seat

1. A dual-use bleacher seat, comprising a backrest, a cushion assembly and two L-shaped hooks, wherein the backrest is connected to the cushion assembly, and the two L-shaped hooks are arranged on left and right sides of a front end of a bottom surface of the cushion assembly respectively; and the dual-use bleacher seat further comprises two U-shaped leg tubes which are rotatably connected to left and right sides of the bottom surface of the cushion assembly respectively; and further comprising four U-shaped elastic connectors, wherein a U-shaped metal sheet is wrapped and mounted in an inner cavity of each of said U-shaped elastic connectors, the four U-shaped elastic connectors are symmetrically mounted at four corners of the bottom surface of the cushion assembly, wherein an upper end of each of said two L-shaped hooks is rotatably connected to an outer wall of each of two of said four U-shaped elastic connectors on a front side of the cushion assembly, and two ends of each said U-shaped leg tube are arranged in the inner cavities of two of said four U-shaped elastic connectors on a left or right side of the cushion assembly respectively and are rotatably connected to the U-shaped elastic connectors.

2. The dual-use bleacher seat according to claim 1 , wherein a concave cavity is formed in the bottom surface of the cushion assembly, and when rotated to be folded on the cushion assembly, the U-shaped leg tubes are received in the concave cavity.

3. The dual-use bleacher seat according to claim 2 , wherein the L-shaped hooks are rotatably connected to the bottom surface of the cushion assembly, and the L-shaped hooks and the U-shaped leg tubes are folded in a staggered manner to be received in the concave cavity.

4. The dual-use bleacher seat according to claim 3 , wherein the backrest is rotatably connected to the cushion assembly.

5. The dual-use bleacher seat according to claim 4 , further comprising a metal connecting piece, wherein an upper end of the metal connecting piece is riveted to a lower left end or a lower right end of the backrest, and a lower end of the metal connecting piece is riveted to a left rear end or a right rear end of the cushion assembly.

6. The dual-use bleacher seat according to claim 2 , wherein the cushion assembly comprises a seat cloth and a rectangular cushion frame, left and right sides of the seat cloth are fixedly mounted on left and right sides of the cushion frame, and the concave cavity is formed between a lower surface of the seat cloth and the cushion frame.

7. The dual-use bleacher seat according to claim 6 , wherein the backrest is rotatably connected to the cushion assembly.

8. The dual-use bleacher seat according to claim 7 , further comprising a metal connecting piece, wherein an upper end of the metal connecting piece is riveted to a lower left end or a lower right end of the backrest, and a lower end of the metal connecting piece is riveted to a left rear end or a right rear end of the cushion assembly.

9. The dual-use bleacher seat according to claim 6 , further comprising L-shaped elastic leg pads which are mounted on sides, towards a ground, of two bent parts of a cross tube of each said U-shaped leg tube.

10. The dual-use bleacher seat according to claim 2 , wherein the backrest is rotatably connected to the cushion assembly.

11. The dual-use bleacher seat according to claim 10 , further comprising a metal connecting piece, wherein an upper end of the metal connecting piece is riveted to a lower left end or a lower right end of the backrest, and a lower end of the metal connecting piece is riveted to a left rear end or a right rear end of the cushion assembly.

12. The dual-use bleacher seat according to claim 1 , further comprising elastic pieces with round pins, wherein the elastic pieces with the round pins are mounted in open ends of outer tubes of the U-shaped leg tubes, and the round pin of each said elastic piece is clamped in a through hole in one side of the corresponding U-shaped elastic connector and is opposite to a press protruding point in the inner cavity of the U-shaped elastic connector; and press marks are arranged on outer walls, corresponding to the press protruding points, of the U-shaped elastic connectors.

13. The dual-use bleacher seat according to claim 12 , wherein oblique concave faces and clamping protrusions are further arranged in the inner cavities of the U-shaped elastic connectors; and when the U-shaped leg tubes are in an unfolded state, outer walls of tube ends of the U-shaped leg tubes abut against the oblique concave faces and the clamping protrusions.

14. The dual-use bleacher seat according to claim 12 , further comprising L-shaped elastic leg pads which are mounted on sides, towards a ground, of two bent parts of a cross tube of each said U-shaped leg tube.

15. The dual-use bleacher seat according to claim 1 , wherein oblique concave faces and clamping protrusions are further arranged in the inner cavities of the U-shaped elastic connectors; and when the U-shaped leg tubes are in an unfolded state, outer walls of tube ends of the U-shaped leg tubes abut against the oblique concave faces and the clamping protrusions.

16. The dual-use bleacher seat according to claim 1 , further comprising L-shaped elastic leg pads which are mounted on sides, towards a ground, of two bent parts of a cross tube of each said U-shaped leg tube.

17. The dual-use bleacher seat according to claim 1 , wherein the backrest is rotatably connected to the cushion assembly.

18. The dual-use bleacher seat according to claim 17 , further comprising a metal connecting piece, wherein an upper end of the metal connecting piece is riveted to a lower left end or a lower right end of the backrest, and a lower end of the metal connecting piece is riveted to a left rear end or a right rear end of the cushion assembly.

19. The dual-use bleacher seat according to claim 1 , further comprising L-shaped elastic leg pads which are mounted on sides, towards a ground, of two bent parts of a cross tube of each said U-shaped leg tube.