Abstract: A lift apparatus for supporting a C-arm or a U-arm of an X-ray machine is provided. The lift apparatus includes an outer shell and an inner shell disposed within the outer shell and configured to slide upward and downward within the outer shell. The C-arm or U-arm is connected to the inner shell. A gas spring is disposed within the inner shell. A first end of the gas spring is connected to a top of the inner shell, and a second end of the gas spring is connected to a bottom of the outer shell through a bottom of the inner shell. Upward and downward movement of the inner shell is driven by expansion and compression of the gas spring.