Adjustable lifting writing board

An adjustable lifting writing board, comprising a writing panel (101), bottom transverse frames (102) symmetrically arranged under the writing panel and self-locking universal wheels (101) symmetrically installed on the bottom surface of the bottom transverse frames, vertical casings (105) are fixedly installed on the upper surfaces of the bottom transverse frames (102), a bottom connecting frame (104) is fixedly connected between the bottom transverse frames (102), and a support plate (106) is arranged under the writing panel (101), and characterized by the following:

• a sliding tube body (201) is arranged inside the vertical casing (105), a first outer tube (213) and a first inner tube (212) are arranged inside the sliding tube body (201), the first inner tube (212) and the first outer tube (213) are connected in a sliding way and maintain sealing, and two groups of first outer tubes (213) and first inner tubes (212) extend and retract synchronously so that the writing panel (101) rises and falls;
• a folding extension tube (219) is arranged under the first outer tube (213) and changes the pressure of the first outer tube (213) and the first inner tube (212) through folding extension, so that liquid flows inside the first outer tube (213) and the first inner tube (212) and then extension and retraction occur between the first outer tube (213) and the first inner tube (212);
• a connecting cross tube (202) is arranged between the two sliding tubes (201), an adjusting block (301) is arranged inside the connecting cross tube (202), a plurality of channels are provided inside the adjusting block (301) for liquid flowing, adjusting plugs (301) are symmetrically arranged inside the adjusting block (301), and a check valve (306) is installed on the surface of the adjusting plug (305) for controlling the flow direction of the liquid;
• a rotating receiving box (203) is fixedly connected to the top of the sliding tube body (201) and an incomplete inner gear ring (204) and a gear block (208) are arranged inside the rotating receiving box to adjust the tilt angle of the writing panel (101).