Thermally controlled door-checks

Claim 1

IN A DOOR CLOSING DEVICE FOR URGING A DOOR TO A CLOSED POSITION WITH A DOOR FRAME, A PAIR OF ARMS, A VERTICAL PIVOT PIN INTERCONNECTING THE ADJACENT ENDS OF SAID ARMS, THE OPPOSITE END OF ONE OF SAID ARMS BEING PIVOTALLY CONNECTED TO THE DOOR, THE OPPOSITE END OF THE OTHER OF SAID ARMS BEING PIVOTALLY CONNECTED TO THE DOOR FRAME, SAID ARMS ASSUMING A SUBSTANTIALLY RIGHT-ANGLE POSITION WHEN THE DOOR REMAINS IN AN OPEN POSITION RELATIVE TO THE DOOR FRAME, TENSIONING MEANS IN ASSOCIATION, WITH ONE OF SAID ARMS FOR INDUCING RELATIVE ANGULAR SHIFTING MOTION TO SAID ARMS FOR BRINGING THE LATTER TO A SUBSTANTIALLY ACUTEANGLED MUTUAL RELATION FOR THEREBY SWINGING THE DOOR TO A CLOSED RELATION WITH RESPECT TO THE FRAME, AN OBLONG CONNECTING MEMBER, MEANS FOR ENGAGING ONE END OF SAID CONNECTING MEMBER WITH THE LOWER END OF SAID PIVOT PIN, SAID OBLONG CONNECTING MEMBER TERMINATING IN AN OPPOSITE END FIXEDLY CARRYING A TERMINAL DISENGAGEABLE CONNECTING DEVICE FOR DISENGAGEABLY CONNECTING THE SAID OPPOSITE END OF THE OBLONG MEMBER TO A FIXED CONNECTING MEMBER LOCATED AT A POINT WHICH IS IN SPACED DISTANCED RELATION WITH SAID PIVOT PIN, SASID DEVICE BEING SPACED FROM CONTACT WITH SAID ARMS, SAID MEANS FOR ENGAGING ONE END OF SAID CONNECTING MEMBER WITH THE LOWER END OF SAID PIVOT PIN AND SAID DEVICE BOTH SUPPORTING SAID OBLONG CONNECTING MEMBER UPON A PLANE DISPOSED BELOW THE PLANE UPON WHICH SAID ARMS SHIFT AND IN A SUBSTANTIALLY TRANSVERSE RELATION WITH ONE, OF SAID ARMS WITH WHICH SAID TENSIONING MEANS IS ASSOCIATED FOR RENDERING SAID TENSIONING MEANS INOPERATIVE FOR MAINTAINING SAID ARMS IN A SUBSTANTIALLY RIGHT-ANGLE POSITION FOR THEREBY MAINTAINING THE DOOR IN A FIXED OPEN POSITION RELATIVE TO THE DOOR FRAME, AND AND INSERT OF FUSIBLE METAL INTERMEDIATELY OF THE ENDS OF SAID OBLONG CONNECTING MEMBER, SAID INSERT BEING CAPABLE OF MELTING BY AN INCREASED TEMPERATURE RESULTING FROM FIRE IN THE VICINITY OF THE DOOR FOR THEREBY SEVERING SAID OBLONG CONNECTING MEMBER FOR RECONDITIONING THE OPERATION OF SAID TENSIONING MEANS FOR SHIFTING SAID ARMS TO A SUBTANTIALLY ACUTE-ANGLED MUTUAL RELATION FOR THEREBY BRINGING THE DOOR TO A CLOSED RELATION WITH RESPECT TO THE DOOR FRAME, THE SEVERED PARTS OF THE OBLONG MEMBER BEING MAINTAINED BY SAID PIN AND THE COOPERABLE RELATION OF SAID CONNECTING DEVICE AND SAID CONNECTING MEMBER IN POSITIONS WHICH ARE OUT OF THE PLANES OF MOVEMENT OF THE DOOR AND THE ARMS TO THEREBY PREVENT SAID SEVERED PARTS FROM INTERFERING WITH AUTOMATIC CLOSING OF THE DOOR.