Protective device

The utility model relates to the technical field of bridge construction protection, and discloses a protection device which comprises a base, a supporting column and a fixing column, a height adjusting assembly is arranged on the inner wall of the fixing column, and a rocker is manually rotated to drive a third gear to rotate in the inner wall of the fixing column. Gear teeth of a third gear are meshed with gear teeth of a fourth gear, so that the third gear rotates and drives the fourth gear to rotate at the top of the base at the same time, a threaded rod fixedly welded to the top of the fourth gear is driven to rotate, and then a connecting rod which is in threaded connection with the outer edge of the threaded rod and is in sliding connection with the inner wall of a fixing column is utilized; the inner wall of a protection rod welded and fixed through the inner wall of the fixing column is slidably connected with the outer wall of the limiting rod, so that the limiting rod can ascend and descend in the i