The invention discloses a dropping prevention mechanism of a device for lifting a four-corner
drill tower from the ground. The dropping prevention mechanism comprises a column, a lifting bracket, a dropping prevention rack, a trailer, a guiding wheel, a traction
rope, a traction pin, a pawl, a fixing pin, a spring and a bolt, wherein an opening is formed in the side face of a column, teeth of the dropping prevention rack are zigzag, a working face is a right-angle side or an approximately right-angled bevel side, the other side is a bevel side greater than 90 degrees, the dropping prevention rack is installed on the side face of the column, the trailer is movably installed in the column, the guiding wheel is installed at the front end of the trailer in a rotary mode, the pawl is rotatably installed on the trailer by utilizing the fixing pin, and the fixing pin is located in the middle of the pawl. A
ratchet is arranged at one end of the pawl and faces the dropping prevention rack, the other end of the pawl is rotatably provided with a connector by utilizing the traction pin, and the traction
rope is connected with the connector. After the traction
rope breaks, the springs rapidly presses the
ratchet, the
ratchet is matched with the dropping prevention rack due to the fact that the
upper tooth-shaped side of the dropping prevention rack is the right-angle side, the right-angle side serves as a supporting surface for supporting the trailer, the trailer rapidly stops to prevent dropping.