Crawling ladder lifting device of vehicle transportation semitrailer

The utility model belongs to the field of lifting of crawling ladders of vehicle transportation semitrailers, particularly relates to a crawling ladder lifting device of a vehicle transportation semitrailer, and aims to solve the problem that a crawling ladder of an existing vehicle transportation semitrailer needs to be manually put down and put away, the following scheme is provided: the crawling ladder lifting device comprises a carriage, and the bottom end of the carriage is fixedly connected with a hollow chassis; a multi-stage telescopic hydraulic oil cylinder is fixedly connected to the inner side of the hollow chassis, a crawling ladder is rotationally connected to the end of the multi-stage telescopic hydraulic oil cylinder, a bridge plate is rotationally connected to the bottom of the carriage, a fixing shaft is fixedly connected into the hollow chassis, and the horizontal position of the inner side of the hollow chassis is perpendicular to the fixing shaft. The ladder lifting device for the vehicle