Gasket and dispensing head assembly for cartridge grease guns

Claim 1

A HAND GREASE GUN INCLUDING THE COMBINATION OF: A CYLINDRICAL BARREL HAVING AN OPEN FRONT END FOR RECEIVING A GREASE CARTRIDGE, THE FORWARD END PORTION OF SAID BARREL PROVIDING EXTERNAL THREADS FOR CONNECTING SAID BARREL FRONT END TO A DISPENSING HEAD; A GREASE CARTRIDGE HAVING AN OPEN REAR END AND BEING INSERTABLE IN SAID BARREL BY EXTENDING SAID REAR END THROUGH SAID BARREL FRONT BED, THE FRONT END EDGE PORTION OF SAID CARTRIDGE BEING PROVIDED WITH A MOUNTING RIM FOR A REMOVABLE CLOSURE, SAID RIM HAVING AN OUTER ANNUALR ATTACHMENT PORTION ENCLOSING THE SAID FRONT END EDGE PORTION AND AN INWARDLY-EXTENDING ANNULAR FLANGE PORTION SURROUNDING A CENTRAL OPENING; AND A DISPENSING HEAD HAVING A REARWARDLY-EXTENDING CYLINDRICAL MOUNTING PORTION RECEIVED OVER SAID BARREL FORWARD END PORTION, SAID HEAD MOUNTNG PORTION HAVING INTERNAL THREADS ADJUSTABLY ENGAGING THE THREADS OF SAID BARREL FORWARD END PORTION, SAID HEAD PROVIDING AN ANNULAR GASKET SEAT WITHIN SAID CYLINDRICAL PORTION AT THE FORWARD END THEREOF; WHEREIN THE IMPROVEMENT COMPRISES AN ANNULAR GASKET OF RESILIENT, FLEXIBLE MATERIAL DISPOSED WITHIN SAID CYLINDRICAL MOUNTING PORTION AND SUPPORTED BY SAID SEAT, SAID GASKET PROVIDING A LATERALLY OUTER ANNULAR PORTION, AND A LATERALLY INNER ANNULAR PORTION PORVIDING A REARWARDLY-EXTENDING CYLINDRICAL PORTION, SAID OUTER ANNULAR PORTION ON ITS REARWARD SIDE BEARING AGAINST AND SEALINGLY ENGAGING SAID RIM ATTACHMENT PORTION AND ALSO ON ITS FORWARD SIDE BEARING AGAINST AND SEALINGLY ENGAGING SAID GASKET SEAT, AND SAID GASKET CYLINDRICAL PORTION HAVING A REARWARD SIDE BEARING AGAINST AND SEALINGLY ENGAGING THE FORWARD SIDE OF SAID RIM FLANGE PORTION INWARDLY OF SAID RIM ATTACHMENT PORTION; WHEREBY SAID HEAD MOUNTING PORTION IS GUIDED INTO THREADED ENGAGEMENT WITH SAID BARREL FORWARD END PORTION AS SAID CARTRIDGE IS INSERTED, AND THE TIGHTENING OF SAID HEAD ON SAID BARREL ACHIEVES A DOUBLE SEAL BETWEEN SAID GASKET AND SAID CARTRIDGE RIM.