Universal lighting fixture replaceable with diversified lamps

A lighting fixture comprising:

• a lamp secured with a connecting tube having a coupling plug integrally formed with the connecting tube;
• and
• a supporting base having a coupling socket formed on an end portion of said base detachably engageable with said coupling plug formed on the connecting tube of said lamp, and having a transformer adapter mounted in said base for reducing voltage from an input power source;
• said coupling plug coaxially rotated in said coupling socket as limited by a limiting screw adjustably fixed in said socket;
• said adapter having a first pole electrically connected with a core conductor formed in each said socket, said plug and said connecting tube for connecting a first pole of said lamp, and having a second pole of said adapter electrically connected with an outer portion formed in each said base, said socket, said plug and said connecting tube for connecting a second pole of said lamp;
• said coupling socket including:
• an outer cylindrical wall defining a socket portion within said cylindrical wall, a core female connector generally cylindrical shaped connected with a first core conductor clad with insulative material to be positioned in a core portion of said coupling socket, a first insulative packing packed between said female connector and said outer cylindrical wall, and said limiting screw adjustably fixed in said cylindrical wall;
• and
• said coupling plug including:
• an outer plug portion engageable with said socket portion of said coupling socket, an inner plug portion protruded axially beyond said outer plug portion to be engageable with said female connector of said socket, a second core conductor connected with said inner plug portion positioned in a core portion in said coupling plug, a second insulative packing packed between said second core conductor and said outer plug portion, and an annular groove circumferentially recessed in said outer plug portion generally perpendicular to an axis of said plug, said annular groove operatively engaged with said limiting screw then inwardly plugged into said groove from said outer cylindrical wall of said socket for rotatably limiting said plug and preventing a releasing of said plug from said socket, the improvement which comprises:
• said outer plug portion of said coupling forked to form a plurality of forked slits longitudinally formed in said outer plug portion for resiliently engaging said outer plug portion of said coupling plug in said socket portion of said coupling socket;
• and
• said outer plug portion of said coupling plug formed with a plurality of shallow grooves longitudinally recessed in said circumference surface of said outer plug portion for slidably guiding said limiting screw on said socket for coupling said plug into said socket.