Locking device for doors, shutters and the like

Claim 1

A LOCKING DEVICE FOR DOORS, SHUTTERS AND THE LIKE, COMPRISING: A LOCK PLUNGER; SAID LOCK PLUNGER CONSISTING OF A LEVER HAVING TWO RIGIDLY CONNECTED ARMS, SAID ARMS FORMING AN OBTUSE ANGLE WITH EACH OTHER, ONE OF SAID ARMS BEING A LOCKING ARM HAVING A FREE END, AND THE OTHER BEING AN OPERATING ARM HAVING A FREE END; SAID LOCK PLUNGER BEING PROVIDED AT THE VERTEX OF SAID OBTUSE ANGLE WITH TWO PINS WHICH PROTRUDE FROM THE SIDES OF THE LOCK PLUNGER; A CASING ENCLOSING SAID LOCKING DEVICE; AND HAVING SIDE WALLS; SAID TWO PINS BEING SLIDABLE IN SLOTS PROVIDED IN SAID SIDE WALLS; THE FREE END OF SAID OPERATING ARM BEING HINGED BY A JOINT TO ONE END OF A PRESSURELOADED LINK; A LOCK MEANS, SUCH AS A LOCK PLATE FASTENED TO A DOOR FRAME, OR THE LIKE; SAID LOCK PLUNGER BEING ADAPTED TO SWING, DURING CLOSING OF THE DOOR OR THE LIKE, AROUND THE FREE END OF SAID LOCKING ARM, SAID LOCK MEANS SERVING AS BEARING FOR SAID SWING; SAID PINS, AT THE SAME TIME, SLIDING IN SAID SLOTS IN A DIRECTION AWAY FROM SAID LOCK MEANS, WHILE THE LOCK PLUNGER TURNS SIMULTANEOUSLY AROUND SAID PINS, SAID OPERATING ARM BEING SIMULTANEOUSLY AND GRADUALLY REMOVED FROM ITS INITIAL POSITION, SAID REMOVAL OF SAID OPERATING ARM BEING FIRST COUNTER-ACTED BY SAID PRESSURE-LOADED LINK AND BEING FINALLY COMPLETED BY THE ACTION OF THE LATTER.