Energy-saving concealed tandem cylinder

The invention discloses an energy-saving concealed tandem cylinder, aiming at solving the problems of overlarge longitudinal dimension, an overlong pull rod, poor overall structural rigidity, high return energy consumption and high impact noise of an existing energy-saving unconcealed tandem cylinder. The energy-saving concealed tandem cylinder is characterized in that a cylinder body serves as a moving component, and a fixed piston-piston rod component is concealed inside the cylinder body to form a front air chamber and a back air chamber for providing push force and a middle air chamber for providing return force. The energy-saving two-stage concealed tandem cylinder has the advantages that the longitudinal dimension of the energy-saving two-stage concealed tandem cylinder is about half of that of an existing two-stage unconcealed tandem cylinder, and accordingly the energy-saving two-stage concealed tandem cylinder is high in structural rigidity and low in manufacturing cost; since the energy-saving two-s