Door closer

Claim 1

A DOOR CLOSER ADAPTED TO BE OPERATIVELY CONNECTED TO A DOOR TO CONTROL THE OPENING AND CLOSING OF THE DOOR WHICH COMPRISES A HOUSING HAVING A PISTON CHAMBER, A PISTON OPERATIVELY MOVABLE IN SAID PISTON CHAMBER WHEREBY MOVEMENT OF SAID PISTON IN SAID PISTON CHAMBER FORCES FLUID FROM SAID PISTON CHAMBER THROUGH A VALVING ARRANGEMENT IN SAID HOUSING TO CONTROL THE SPEED AT WHICH THE DOOR OPENS AND CLOSES, AND VALVING ARRANGEMENT COMPRISING A GROUP OF PASSAGEWAYS WITHIN SAID HOUSING, EACH OF SAID PASSAGEWAYS IN SAID GROUP COMMUNICATING WITH SAID PISTON CHAMBER AT SPACED POINTS ALONG THE LONGITUDINAL AXIS OF SAID PISTON CHAMBER, A MAIN PASSAGEWAY IN SAID HOUSING COMMUNICATING WITH EACH OF SAID PASSAGEWAYS IN SAID GROUP, SAID MAIN PASSAGEWAY HAVING A VALVE THEREIN, A BY-PASS PASSAGEWAY HAVING ENDS WHICH COMMUNICATE WITH SAID MAIN PASSAGEWAY ON OPPOSITE SIDES OF SAID VALVE IN SAID MAIN PASSAGEWAY, SAID BY-PASS PASSAGEWAY HAVING A ONE-WAY VALVE THEREIN, SAID ONE-WAY VALVE PERMITTING FLUID TO FLOW THROUGH SAID BY-PASS PASSAGEWAY IN ONLY ONE DIRECTION, SAID GROUP OF PASSAGEWAYS COMPRISING A FIRST PASSAGEWAY, A SECOND PASSAGEWAY, A THRD PASSAGEWAY AND A FOURTH PASSAGEWAY EACH OF WHICH COMMUNICATES WITH SAID PISTON CHAMBER AND SAID MAIN PASSAGEWAY AT DIFFERENT POSINTS ALONG ITS LONGITUDINAL AXIS, SAID FIRST AND FOURTH PASSAGEWAYS COMMUNICATING WITH SAID PISTON CHAMBER AT OPPOSITE ENDS OF THE MOVEMENT OF SAID PISTON IN SAID PISTON CHAMBER, SAID MAIN PASSAGEWAY HAVING A FIRST VALVE AND A SECOND VALVE THEREIN, SAID FIRST VALVE BEING POSITIONED BETWEEN WHERE SAID FIRST PASSAGEWAY AND SAID SECOND PASSAGEWAY COMMUNICATE WITH SAID MAIN PASSAGEWAY, SAID SECOND VALVE BEING POSITIONED BETWEEN WHERE SAID SECOND PASSAGEWAY AND SAID THIRD PASSAGEWAY COMMUNICATE WITH SAID MAIN PASSAGEWAY.