Patent ID: 7977595

Claim:
An automatic discharging apparatus for a closing spring in an air circuit breaker comprising a main body, a cradle for supporting the main body to be pushed in or pulled out, and a switching mechanism which includes a closing spring for applying elastic energy to close the air circuit breaker, a cam for allowing the closing spring to charge elastic energy or discharge the charged elastic energy, and a cam shaft for rotatably supporting the cam, the apparatus comprising: a cam shaft rotation preventing unit configured to restrict the rotation of the cam shaft by an elastic restoring force of the closing spring, the cam shaft rotation preventing unit comprising: a ratchet wheel installed on the cam shaft to be rotatable together with the cam shaft, and at least one ratchet rotatable to a position at which the ratchet wheel and the cam shaft are allowed to be rotated such that the closing spring discharges elastic energy, or a position at which the ratchet wheel and the cam shaft are restricted from being rotated such that the closing spring charges elastic energy; and a unit for releasing the cam shaft rotation preventing unit connected to the cam shaft rotation preventing unit and configured to allow the cam shaft to be rotated by the elastic restoring force of the closing spring according to positions where the main body is pulled out of the cradle, the unit for releasing the cam shaft rotation preventing unit comprising: a lever coaxially connected to a rotational shaft of the at least one ratchet and configured to rotate the at least one ratchet according to the rotation thereof to the position at which the ratchet wheel and the cam shaft are allowed to be rotated, a link mechanism being in contact with the lever, and configured to rotate the lever to make elastic energy of the closing spring discharged by allowing the rotations of the ratchet wheel and the cam shaft at a position at which the main body is pulled out, and a spring configured to provide elastic energy for rotating the lever to the link mechanism at the position at which the main body is pulled out.