Anti-falling structure of drainage tube

The utility model discloses an anti-drop structure of a drainage tube, which comprises a sleeve seat sleeved at the joint of the drainage tube and an external tube, the end part of the drainage tube is provided with an integrated plug inserted into the inner side of the external tube, the upper and lower surfaces of the sleeve seat are respectively and fixedly provided with a T-shaped guide pillar, the T-shaped guide pillar is sleeved with a clamping plate in a sliding manner, and the clamping plate is fixed on the outer side of the external tube. Two anti-falling insertion blocks are fixed to the inner side of the clamping plate, annular grooves are formed in the surfaces of the drainage tube and the external connection tube, the ends of the anti-falling insertion blocks penetrate to the inner sides of the annular grooves, limiting structures are further arranged on the two sides of the T-shaped guide column, and each limiting structure comprises a side groove, a spring and an isosceles trapezoid telescopic