Rotatable head for luminaires

Claim 1

A LUMINAIRE COMPRISING, IN COMBINATION, A HEAD HAVING AN EXTERIOR CIRCUMFERENTIALLY EXTENDING FLANGE PORTION, AN OPTICAL ASSEMBLY INCLUDING A REFRACTOR HAVING A PLURALITY OF PRISMS ARRANGED THEREON AND A REFLECTOR, A LIGHT SOURCE SUPPORTED FROM SAID HEAD AND POSITIONED WITHIN SAID OPTICAL ASSEMBLY AND RELATIVE TO SAID PRISMS SO THAT SAID OPTICAL ASSEMBLY TRANSMITS LIGHT IN A PREDETERMINED PATTERN, AN ADAPTER MEMBER INTERPOSED BETWEEN SAID OPTICAL ASSEMBLY AND SAID HEAD AND HAVING AN EXTERIOR CIRCUMFERENTIALLY EXTENDING FLANGE PORTION, MEANS FOR RELEASABLY CONNECTING IN A FIXED ORIENTATION SAID OPTICAL ASSEMBLY TO SAID ADAPTER MEMBER, A GENERALLY U-SHAPED IN CROSS SECTION CLAMPING RING EMBRACINGLY ENGAGING SAID FLANGE PORTIONS OF BOTH SAID HEAD AND SAID ADAPTER, AND MEANS FOR SELECTIVELY TIGHTENING SAID CLAMPING RING ON SAID FLANGE PORTIONS TO FIXEDLY CONNECT SAID ADAPTER MEMBER TO SAID HEAD AND LOOSENING SAID CLAMPING RING TO SUPPORT SAID ADAPTER FROM SAID HEAD FOR ROTATION RELATIVE TO SAID HEAD, WHEREBY SAID OPTICAL ASSEMBLY IS ROTATABLY ADJUSTABLE RELATIVE TO SAID LIGHT SOURCE TO VARY THE POSITION OF SAID PREDETERMINED PATTERN OF LIGHT.