Hot melt adhesive extruder

Claim 1

IN A HOT MELT ADHESIVE EXTRUDER HAVING A HOT MELT ADHESIVE APPLYING MEMBER, HAVING AN ORIFICE THROUGH WHICH MOLTEN ADHESIVE IS ADAPTED TO FLOW, A HEATING CHAMBER FOR PLACING THE ADHESIVE IN MOLTEN CONDITION, A SCREW IN SAID CHAMBER FOR FORCING THE MOLTEN ADHESIVE WITHIN SAID CHAMBER THROUGH SAID ORIFICE, DRIVE MEANS FOR ROTATING THE SCREW, AND MEANS FOR FEEDING HOT MELT ADHESIVE INTO SAID CHAMBER, THE IMPROVEMENT OF MEANS FOR COOPERATING TO INHIBIT THE FLOW OF MOLTEN ADHESIVE FROM SAID CHAMBER INTO SAID ORIFICE UPON CESSATION OF OPERATION OF SAID SCREW, THE INHIBITING MEANS COMPRISING IN COMBINATION A VALVE INCLUDING A VALVE PLUG ON SAID SCREW AND VALVE SEAT AT SAID ORIFICE FOR RECEIVING SAID PLUG, THE VALVE PLUG BEING AN INTEGRAL EXTENSION OF SAID SCREW AND THE VALVE SEAT BEING DISPOSED WITHIN SAID CHAMBER IN CONCENTRIC RELATIONSHIP WITH RESPECT TO THE ORIFICE, SCREWSHIFTING MEANS COOPERATING TO SHIFT THE SCREW TO OPEN AND CLOSE THE VALVE, THE SCREW-SHIFTING MEANS BEING COUPLED TO ONE END OF THE SCREW AND BEING SO CONSTRUCTED AND ARRANGED THAT IT NORMALLY SHIFTS SAID SCREW TO CAUSE SAID PLUG TO REST ON SAID SEAT TO CLOSE SAID VALVE AND UPON ACTUATION THEREOF TO SHIFT SAID SCREW TO WITHDRAW SAID PLUG FROM SAID SEAT TO OPEN SAID VALVE, THE SAID DRIVE MEANS INCLUDING A MAIN DRIVE, A DRIVE CONNECTION COUPLING SAID DRIVE AND SAID SCREW SUCH THAT NORMALLY PREVENTS THE DRIVE FROM ROTATING THE SCREW AND UPON ACTUATION THEREOF, SAID DRIVE IS ADAPTED TO ROTATE SAID SCREW, AND SYNCHRONIZATION MEANS INTERCONNECTING SAID SCREW-SHIFTING MEANS AND SAID DRIVE CONNECTION FOR OPENING SAID VALVE SUBSTANTIALLY SIMULTANEOUSLY WITH THE ACTUATION OF SAID DRIVE CONNECTION AND CLOSING OF SAID VALVE SUBSTANTIALLY SIMULTANEOUSLY WITH THE RETURN OF SAID DRIVE CONNECTION TO ITS NORMAL CONDITION.