Patent ID: 7966693

Claim:
A hinge apparatus having an automatic return function, the automatic return hinge apparatus comprising: an upper body on a circumferential surface of which a first hinge which is fixed to a door is integrally formed and whose upper end portion is blocked by an upper cap on the inner side surface of which a recess is formed; a lower body on a circumferential surface of which a second hinge which is fixed to a door frame is integrally formed and whose lower end portion is blocked by a lower cap which is connected in a sealing manner; a shaft whose lower end portion is rotatably installed in the upper portion of the lower body and whose upper end portion is inserted into the recess of the upper cap; a piston whose outer circumference is slidably installed along the inner circumferential surface of the lower body and which divides the inner portion of the lower body into upper and lower chambers; a rotational/linear motion converter which converts a rotational motion of the shaft into an axial linear motion of the piston when the rotational force of the door is applied to the shaft according to the rotation of the door; a damping unit which provides a damping function selectively in the case that the piston descends/ascends according to opening/closing of the door; and a return unit which provides a restoring force to the rotational/linear motion converter in order to return the door to an initial position at the time when the door is closed.