Door operating mechanism

Claim 1

IN AN OVERHEAD DOOR OPERATING MECHANISM THAT INCLUDES AN ELECTRIC MOTOR DRIVEN RECIPROCABLE CARRIAGE FOR OPENING AND CLOSING OF A DOOR, A LINK FOR CONNECTING A CARRIAGE TO A DOOR COMPRISING A COMBINATION, A HYDRAULIC SHOCK ABSORBER INCLUDING A CYLINDER HAVING A PISTON RECIPROCABLE THEREIN AND A CONNECTING ROD CONNECTED AT ONE END TO SAID PISTON AND HAVING THE OTHER END EXTENDING EXTERNALLY OF SAID CYLINDER, A FIRST PIVOTAL CONNECTION AT THE ROD FREE END OF SAID CYLINDER FOR CONNECTION WITH A DOOR, AN OFFSET BRACKET CONNECTED AT AN END PORTION OF SAID CONNECTING ROD, A SECOND PIVOTAL CONNECTION ON SAID BRACKET FOR CONNECTION WITH A RECIPROCABLE CARRIAGE, A COLLAR MOUNTED ON SAID PISTON ROD BETWEEN SAID CYLINDER AND SAID PIVOTAL CONNECTION ON SAID ROD, AND A COMPRESSION SPRING INTERPOSED BETWEEN SAID COLLAR AND SAID CYLINDER URGING SAID CYLINDER AWAY FROM SAID COLLAR TO DISPOSE SAID PISTON INTERMEDIATE THE ENDS OF SAID CYLINDER TO PROVIDE FOR EXTENSION OF THE SHOCK ABSORBER IN ONE DIRECTION OF MOVEMENT AND COMPRESSION IN THE OPPOSITE DIRECTION OF MOVEMENT THEREOF ON OPENING OR CLOSING OF A DOOR, SAID COMPRESSION SPRING BEING AXIALLY ALIGNED WITH SAID PISTON ROD, SAID PISTON ROD BEING AXIALLY ALIGNED WITH SAID FIRST PIVOTAL CONNECTION, SAID OFFSET BRACKET LOCATING SAID END PORTION OF SAID CONNECTING ROD INWARDLY OF THE DOOR A GREATER DISTANCE THAN SAID FIRST PIVOTED CONNECTION WHEN THE DOOR IS CLOSED TO LOCATE THE LONGITUDINAL AXIS OF SAID SHOCK ABSORBER AT A PREDETERMINED INCLINATION WITH RESPECT TO THE CLOSED DOOR, SAID SPRING BEING COMPRESSED BETWEEN SAID COLLAR AND SAID CYLINDER WHEN SAID SHOCK ABSORBER IS AT SAID PREDETERMINED INCLINATION TO APPLY A DOWNWARD DOOR CLOSING FORCE ON THE DOOR THROUGH SAID SECOND PIVOTAL CONNECTION FOR BIASINGLY POSITIONING THE DOOR TOWARD A FULLY CLOSED POSITION.