Telescopic arm for bridge detection

The invention provides a telescopic arm for bridge detection. In the working process, a telescopic motor is driven to drive a second sliding sleeve through a driving lead screw to drive a rotating mechanism and a second telescopic mechanism to move front and back along a first sliding sleeve, and the second telescopic mechanism is adjusted to the proper height; a rotating motor drives the second telescopic mechanism to rotate through a rotating disc and a connecting plate to adjust the second telescopic mechanism to a proper angle; a first driving motor drives a first driving disc to rotate through a first driving shaft, and meanwhile, a second driving motor drives a second driving disc to rotate through a second driving shaft; and in other words, the first driving disc and the second driving disc rotate simultaneously to drive a steel coil penetrating through a driving through hole to move up and down so as to drive the telescopic rod with the smallest size to move, then the height ofthe telescopic rod with