Tamper-proof door latching mechanism

Claim 1

IN A LATCH MECHANISM FOR LATCHING A DOOR, A DOOR AND A DOOR FRAME WHERE THE DOOR IS HINGEDLY MOUNTED TO THE DOOR FRAME ALONG ONE EDGE THEREOF, THE DOOR FRAME INCLUDING A LATCH MECHANISM HAVING A MOVABLE LATCH MEANS AND A SWINGING HANDLE MEMBER FOR MOVING THE LATCH MEANS BETWEEN A LOCKED AND AN UNLOCKED POSITION, THE DOOR INCLUDING A KEEPER MEANS FOR ENGAGEMENT BY THE LATCH MEANS FOR LOCKING THE DOOR IN A CLOSED POSITION; THE INVENTION COMPRISES A LOCKING MEANS FOR HOLDING THE HANDLE OF THE LATCH MECHANISM IN THE LOCKED POSITION, SAID HANDLE HAVING A MAIN PORTION AND A REMOVABLE KEY PORTION THAT MUST BE INSERTED IN THE MAIN HANDLE PORTION IN ORDER TO BE ABLE TO MOVE THE LATCH MECHANISM, THE MAIN HANDLE PORTION BEING CONNECTED TO THE LATCH MEANS OF THE LATCH MECHANISM, AND A GUIDE RAIL COOPERATING WITH THE MAIN HANDLE PORTION THROUGHOUT THE EXTENT OF THE MOVEMENT THEREOF, THE MAIN HANDLE PORTION HAVING SLOT MEANS INTERFITTED WITH A GUIDE RAIL, THE REMOVABLE KEY PORTION ALSO HAVING SLOT MEANS THAT IS REGISTRABLE WITH THE FIRST-MEMTIONED SLOT MEANS AND INTERFITTED WITH THE GUIDE RAIL EXCEPT WHEN THE HANDLE IS IN ITS LOCKED POSITION, WHEREBY THE REMOVABLE KEY MAY ONLY BE INSERTED AND REMOVED FROM THE MAIN HANDLE PORTION WHEN THE HANDLE IS IN ITS LOCKET POSITION, AND A SLIDING BOLT MEMBER WITHIN THE MAIN HANDLE PORTION, BIASING MEANS EXERTED ON THE BOLT MEMBER TO CAUSE INTERFERENCE WITH THE GUIDE RAIL SO AS TO HOLD THE HANDLE MEMBER IN THE LOCKED POSITION WHEN THE KEY MEMBER IS ABSENT THEREFROM.