Cylinder head assemblies for spark ignition internal combustion engines

Claim 1

IN A SPARK IGNITION INTERNAL COMBUSTION ENGINE, THE COMBINATION COMPRISING: A CYLINDER HEAD ASSEMBLY INCLUDING A CYLINDER HEAD BLOCK HAVING AT LEAST ONE HEMISPHERICAL COMBUSTION CHAMBER THE CENTER OF WHICH LIES ON THE AXIS OF THE CYLIDNER; INLET AND EXHAUST PORTS OPENING INTO SAID CHAMBER ON OPPOSITE SIDES OF A CENTRAL LONGITUDINAL PLANE THROUGH THE CHAMBER AND SO DISPOSED THAT THE AXIS OF THE INLET PORT LIES IN A SECOND PLANE EXTENDING LONGITUDINALLY OF THE COMBUSTION CHAMBER AND INCLINED TO SAID CENTRAL LONGITUDINAL PLANE AND THE AXIS OF THE EXHAUST PORT LIES IN A THIRD PLANE EXTENDING LONGITUDINALLY OF THE COMBUSTION CHAMBER AND INCLINED TO SAID CENTRAL LONGITUDINAL PLANE ON THE OPPOSITE SIDE THEREOF FROM SAID SECOND PLANE, THE THREE PLANES INTERSECTING IN A COMMON LINE ON WHICH LIES THE CENTER OF THE HEMISPHERICAL COMBUSTION CHAMBER; INLET AND EXHAUST POPPET VALVE MEANS CONTROLLING THE FLOW OF GAS THROUGH SAID INLET AND EXHAUST PORTS RESPECTIVELY, THE AXIS OF EACH OF SAID VALVE MEANS BEING COINCIDENT WITH THE AXIS OF THE CORRESPONDING PORT AND EACH OF SAID VALVE MEANS INCLUDING A STEM, A VALVE HEAD CARRIED BY SAID STEM, SAID HEAD BEING LOCATED WITHIN THE SAID CHAMBER; GUIDE MEANS IN SEAT FORMED IN A WALL OF SAID CHAMBER; GUIDE MEANS IN SAID HEAD BLOCK SLIDABLY RECEIVING SAID VALVE STEMS; AT LEAST ONE OF SAID VALVE MEANS BEING ARRANGED WITH ITS AXIS IN A PLANE PARALLEL TO AND OFFSET FROM A CENTRAL TRANSVERSE PLANE THROUGH THE CHAMBER NORMAL TO THE CENTRAL LONGITUDINAL PLANE; MEANS DEFINING A POCKET IN THE WALL OF SAID COMBUSTION CHAMBER, THE VALVE SEAT FOR SAID OFFSET VALVE BEING LOCATED IN SAID POCKET AND THE SURFACE OF SAID SEAT BEING A SURFACE OF REVOLUTION ABOUT THE AXIS OF THE OFFSET VALVE; A SPARK PLUG MOUNTED IN SAID CYLINDER HEAD BLOCK AND PROJECTING INTO SAID COMBUSTION CHAMBER, THE ELECTRODES OF SAID SPARK PLUG BEING NEAR THE CENTRAL VERTICAL AXIS OF THE COMBUSTION CHAMBER; AND VALVEOPERATING MEANS INCLUDING A SINGLE CAM SHAFT MOUNTED ON THE CYLINDER HEAD BLOCK AND HAVING A SEPARATE ROCKER FOR OPERATING EACH OF SAID VALVES, A SEPARATE SUPPORT FOR EACH OF SAID ROCKERS, SAID SUPPORTS BEING ELONGATED MEMBERS ARRANGED TO SUPPORT THE ROCKERS WHILE SUFFERING SUBSTANTIALLY ONLY LONGITUDINAL STRESSES.