The present invention relates generally to door hinges, and more particularly to gravity activated, self closing door hinges. Such hinges may be used in high traffic, restaurant kitchen swing doors requiring a full range of swing to both sides of the door frame, and in refrigerator doors requiring a range of motion to only one side of the door frame.
A typical gravity activated, self closing door hinge has a door jamb mounting structure and a pivot post for supporting a door panel. The hinge also has a complementary cam arrangement coupling the jamb mounting structure and the pivot post together in a manner which biases the door panel to a closed position. When closed, the weight of the door panel is transferred through the pivot post to thehostile conditions, the Hentzi hinge is vulnerable to damage due to the exposed nature of Hentzi's cam arrangement. The impact of a heavy object on the exposed cam could cause imbalance or damage the cam faces, resulting in a rapid degradation of the hinge. The closing speed of Hentzi's door may be too slow for some applications because the cam mechanism is the sole provider of the closing force.
The possibility of cam damage is minimized in the hinges of U.S. Pat. Nos. 4,631,777 to Takimoto, and 4,030,161 to Loikitz, which teach the shielding and sealing of the cam area. These hinges, however, are undesirable for use in a two way traffic door because they are not designed to enable a door panel to swing to both sides of