The invention relates to a weight box with adjustable
mass and maintenance of the position of a
mass center. The weight box comprises a box body, the upper surface of the box body is open so that different balancing weights are conveniently replaced, balancing weight components are arranged in the box body, and comprise narrow supporting plates, eccentric balancing weights, hollow balancing weightgroups and / or
solid balancing weights; the box body is formed by connecting a left side plate, a right side plate, a bottom plate and a rear baffle through screws, the front surface of the box body is connected with a collision device, the rear baffle of the box body is provided with a
threaded rod for compressing the balancing weight components in the box body, and the upper portions of the leftside plate and the right side plate of the box body are respectively provided with hanging plates. The box body structure is used as the counterweight, and the counterweight
mass is adjusted by adopting a mode of replacing the hollow counterweight and the
solid counterweight. Compared to a traditional mode, the weight box with the adjustable mass and maintenance of the position of the mass centerhas the following advantages in that: 1. the mass is adjustable, and can ensure the adjusting precision, 2, when the mass is adjusted, the position of the
mass center is kept unchanged in the up-downdirection and the left-right direction, 3, the structure is firm and fast, and the rigidity can be ensured, 4, the counterweight adjustment is convenient and fast to operate, and 5, the weight box has expansibility.