The invention discloses a free tensioning discharging frame for automatic feeding, and relates to a production line of an air pipe adjusting valve outer frame. The free tensioning discharging frame is applied to discharging of outer frame steel plates. The free tensioning discharging frame comprises a base, a rolling shaft, a discharging plate and a tensioning control rocking handle; the rolling shaft is arranged on the base; the discharging plate is arranged at the far end of the rolling shaft; and the position, opposite to the discharging plate, of the other end of the rolling shaft is connected with the tensioning control rocking handle. The free tensioning discharging frame further comprises a power device controlling the rolling shaft to operate. The power device is composed of a motor and a belt; an electrical switch is arranged on the motor; and the motor is connected with the rolling shaft through the belt. The free tensioning discharging frame has the beneficial effects that due to the structure of a single cantilever, roll materials can be rapid and convenient to replace; a core of the roll materials is controlled by the material core tensioning control rocking handle, and matched adaptation can be carried out on the inner diameter of the roll materials; discharging is driven by the motor, and the electrical switch is adopted to control discharging to be matched with speed of the production line of an air pipe adjusting valve; and labor intensity is reduced, and the production efficiency is improved.