Patent ID: 7506474

Claim:
A door opening and closing mechanism for pivotably supporting a first door in front of an opening formed in a main unit of an appliance in such a way that the first door can be opened and closed, wherein a first end of the first door and a first end of the main unit are located at a side of the main unit where a hinge pin, about which the first door pivots, is arranged, and wherein said first end of the first door and said first end of the main unit constitute a first end portion and wherein a second end of the first door and a second end of the main unit are located at a side of the main unit opposite said side of the main unit where the hinge pin is arranged and constitute a second end portion, the mechanism comprising: said hinge pin provided on one of the main unit and the first door, the hinge pin having the first door pivoted thereon; a cam member provided on another one of the main unit and the first door not having the hinge pin, the cam member having first and second cam surfaces formed thereon, the second cam surface being a convex cylindrical surface, the first cam surface extending from the second cam surface; a camming structure provided on the one of the main unit and the first door having the hinge pin, the camming structure making a constant engaging contact with the cam member and having an inner curved surface concentric with the hinge pin, the camming structure being arranged along the cylindrical surface so as to slide on the cylindrical surface when in contact with the second cam surface of the cam member, the hinge pin being arranged on a side of the camming structure facing a center of the cylindrical surface; and a hinge groove comprising an elongate hole closed at both ends, the hinge groove being formed in the cam member, the hinge groove having the hinge pin loosely fitted thereinto, and the camming structure being located outside the hinge groove, wherein, as the camming structure moves along the first cam surface toward the second cam surface, the hinge pin moves relative to the hinge groove to permit the first door to slide toward the first end of the main unit from the second end of the main unit so that the hinge pin and the hinge groove engage with each other and at the same time the camming structure and the second cam surface slide-engage with each other and thereby restrict movement of the hinge pin relative to the hinge groove.