Gravity return hinge having an axle rod in an axle sleeve

An automatic return hinge comprising one primary hinge and one secondary hinge, and said primary hinge including a left side primary hinge piece to be attached to a suitable upper portion of the jamb, and a right side primary hinge piece to be attached to a suitable upper portion of the door, and a locating piece of said right side primary hinge piece being furnished with a sleeve in which an axle sleeve being fitted, and around said axle sleeve, three locating balls being mounted at an equal distance of 120.degree. angle, and in said axle sleeve fitting an axle rod with three slantingly upwards spiral grooves separated at an equal distance of 120.degree. angle so as to match said three locating balls;

• and at one side of a locating piece of the left side primary hinge piece, having two axle seats with locating grooves in corresponding position;
• and when the sleeve of said right side primary hinge piece being placed in between the two axle seats of the left side primary hinge piece, the flat ends of the axle rod then being inserted into said locating grooves, and being fixed with screws;
• and when opening the door moving upwards slightly as a result of the matching function of said spiral grooves and said locating balls, and upon the door opening being over, the door automatically returning to shutting position as a result of door gravity effect.