Bridge detection device suitable for load detection of main beam

The invention discloses a bridge detection device suitable for load detection of a main beam. The bridge detection device comprises a vehicle body, supporting mechanisms are installed on the two sides of the vehicle body, a cavity A is formed in one side of the top of the vehicle body, a transmission device is installed in the cavity A, and the top end of the transmission device penetrates through the cavity A to be fixedly provided with a rotating disc. An installed lifting mechanism drives a rectangular sleeve rod to ascend and descend, the rectangular sleeve rod ascends and descends to drive a transverse plate to ascend and descend, a vibration pickup installed at the top end of the transverse plate makes contact with the bottom end of a bridge, an installed servo motor B rotates to drive a second bevel gear to rotate, the second bevel gear is meshed with a first bevel gear, and therefore a forward and reverse lead screw is driven to rotate; a sliding block is driven to move through the rotation of the for