"Class 72g, 4
An Authorship Certificate for an Invention
Description of a collapsible single seat tracked tank, attached to the authorship certificate for A.N. Yermolovich, submitted on June 15th, 1931 (inquiry #90258). The issuing of the authorship certificate was announced on September 30th, 1933.
The proposed one-seat tank has a mobile weight that moves the rear half of the tank up and down in order to achieve the ability to bend itself along the central joint, which will assist in movement on cross-country terrain.
The schematic in fig. 1 shows the tank from the side, fig. 2 shows it reversing over an obstacle, and fig. 3 shows a diagram of the mobile weight mechanism.
The proposed tank (figs. 1-3) is equipped with three wheels, with which it can move about off road. In order to bend about the central joint A (fig. 2), the tank is equipped with a sliding weight Д and a weight Б (fig. 3). The latter automatically raises or lowers the rear of the tank when on off-road terrain (fig. 2).
The tank is equipped with a rubberized cloth track E, and covered on the side by caps Ж. 3 machineguns and one gunner (also driver) are positioned in the front of the tank. The engine И, fuel tank K, and muffler L are placed in the rear of the tank."
The solution seems unconventional, and went unused for many decades, but it did find application in modern military robots.