Height-adjustable washstand

A height-adjustable washstand, comprising:

• a cylinder 20 fixedly installed on the bottom of a washstand 10, said cylinder containing a piston 21 integrally coupled with a lifting rod 22 and a compression spring 23, said piston being moved by water pressure in an up and down direction within said cylinder;
• a rod casing 25 having an open upper portion and a lower portion thereof fixedly installed on a floor 15 and, said lifting rod 22 of said cylinder 20 being inserted into said open upper portion of said rod casing 25 to be moved in said up and down direction and to be fixed at a desired level so that the height of said lifting rod can be adjusted;
• solenoid valves SA, SB of a valve body 30 for simultaneously controlling an amount of water supplied through a water supplying pipe 31 flexibly connected to a water main 11 on the side of a wall 14 and for controlling an amount of water discharged through a water discharging pipe 32, by means of opening and closing operations of said solenoid valves;
• booster tanks DA, DB of said valve body 30 constructed such that pressure plates 33, 34 in said booster tanks are vertically moved by means of supply and discharge of said water controlled by said solenoid valves SA, SB in order to move said piston 21 of said cylinder 20 in said up and down direction by water pressure;
• a power supply PW for supplying electric power to said solenoid valves SA, SB that are opened and closed in opposite manners according to up and down movement of said piston;
• and
• a lift-operating switch SW for selectively actuating said up and down movement of said piston 21.