Suction device

A suction device comprising:

• a suction cup comprising a top plane and a bottom plane attaching to a surface;
• a vertical bar installed with a through hole and connected with the suction cup, for pulling the suction cup;
• a first support cap having an opening in a center of the first support cap which the vertical bar is able to be placed through and a first pair of gaps symmetrical with respect to the center in a rim of the first support cap;
• a sleeve installed with a pair of guiders and connected with the first support cap, for containing the vertical bar;
• a linkage unit combined with the sleeve and the vertical bar, for controlling the vertical bar to move in the sleeve to pull the suction cup, to enable a suction functionality of the suction cup;
• and
• a second support cap installed between the suction cup and the first support cap, combined with the first support cap through relative rotation, and having an opening in a center of the second support cap which the vertical bar is able to be placed through and a second pair of gaps symmetrical with respect to the center of the second support cap in a rim of the second support cap.