Swinging door hinge

Claim 1

A SWINGING DOOR HINGE COMPRISING: A FIRST PIVOT ELEMENT ADAPTED TO BE FASTENED TO THE BOTTOM EDGE OF A DOOR, SAID ELEMENT HAVING A PINTLE ACCOMMODATING BORE AND BEING TRUNCATED TO DEFINE A FLAT SURFACE DISPOSED AT AN ANGLE WITH RESPECT TO SAID BOTTOM EDGE, SAID SURFACE DEFINING A PLANE THAT INTERSECTS THE PLANE OF SAID BOTTOM EDGE, SAID BORE PASSING CENTRALLY THROUGH SAID FLAT SURFACE, SAID SURFACE TERMINATING IN A HORIZONTAL SHELF AT ITS LOWER EXTREMITY; A SECOND PIVOT ELEMENT ADAPTED TO BE FASTENED ADJACENT ONE SIDE JAMB OF A DOORFRAME SPACED APART THEREFROM AND ALIGNED BENEATH SAID FIRST PIVOT ELEMENT IN SUPPORTING RELATIONSHIP, SAID SECOND PIVOT ELEMENT HAVING A PINTLE ACCOMMODATING BORE VERTICALLY ALIGNED WITH THE PINTLE ACCOMMODATING BORE OF SAID FIRST PIVOT ELEMENT AND BEING TRUNCATED TO DEFINE A FLAT SURFACE ARRANGED TO BE IN SUBSTANTIALLY FULL CONTACT WITH THE FLAT SURFACE OF SAID FIRST PIVOT ELEMENT WHEN SAID DOOR ASSUMES ITS POSITION CLOSING SAID DOORFRAME, THE BORE OF SAID SECOND PIVOT ELEMENT PASSING CENTRALLY THROUGH THE FLAT SURFACE THEREOF, THE FLAT SURFACE OF SAID SECOND PIVOT ELEMENT TERMINATING IN A HORIZONTAL SHELF AT ITS UPPER EXTERMITY; AND PINTLE MEANS FIXED WITH RESPECT TO ONE OF SAID ELEMENTS AND ADAPTED TO ENTER SAID BORES FOR MAINTAINING AXIAL ALIGNMENT OF SAID ELEMENTS, WHEREBY PARTIAL OPENING OF SAID DOOR CAUSES A VERTICAL DISLOCATION OF SAID PIVOT ELEMENTS, SAID FIRST PIVOT ELEMENT RIDING ON SAID SECOND PIVOT ELEMENT WITH LINE CONTACT THEREBETWEEN, SAID DISLOCATION SITUATING SAID DOOR IN AN UNSTABLE POSITION FROM WHICH GRAVITY TENDS TO RETURN SAID DOOR TO ITS POSITION CLOSING SAID DOORFRAME AND WHEREBY ENGAGEMENT OF SAID SHELVES AT THE EXTREME POSITIONS OF THE ARCUATE TRAVEL OF SAID DOOR ESTABLISHES TWO STABLE, OPEN POSITIONS OF SAID DOOR.