Automatic grounding device

An automatic grounding device is characterized in that a plurality of resistor assemblies are arranged in parallel, sliding guide columns are sleeved below the resistor assemblies, springs are attached to the lower ends of the sliding guide columns, the bottom ends of the springs are placed in grooves of a base, an upper cover plate is arranged at the upper end of the base, and the upper sections of the plurality of parallel sliding guide columns penetrate through the upper cover plate and a mounting frame to be arranged on the base and are screwed and fixed through screws; an attaching plate is mounted on the mounting frame, and the plurality of resistor assemblies are clamped on the attaching plate. When assembling operation is carried out one by one, the size error of the shell can be automatically lifted along with the combined action of the operation pressure and the elastic force of the spring until the shell is in interference fit with the part on the resistor assembly, so that the shell is tightly att