Middle beam and underframe

The middle beam comprises an upper cover plate, a lower cover plate and webs, the lower cover plate and the upper cover plate are oppositely arranged in a spaced mode, the webs are arranged between the upper cover plate and the lower cover plate in pairs, a cavity is defined by the upper cover plate, the lower cover plate and the webs, a first opening is formed in the upper cover plate, and a second opening is formed in the lower cover plate. A cavity is formed in the middle beam, a first opening is formed in the middle beam, the first opening is communicated with the cavity, a second opening is formed in the position, corresponding to the first opening, of the web, and the first opening and the second opening are communicated up and down so that part of goods to be transported can fall into the lower portion of the middle beam through the first opening and the second opening. 本发明公开了一种中梁以及底架，所述中梁包括上盖板、与所述上盖板相对间隔设置的下盖板、以及成对设置在所述上盖板和所述下盖板之间的腹板，所述上盖板、所述下盖板和所述腹板围成腔体，所述上盖板开设有第一开口，所述第一开口与所述腔体连通，在所述腹板与所述第一开口相对应的位置开设