Track lighting fixture

A fixture adapter for securing a lighting fixture to a lighting track, said adapter comprising a base, at least one actuating member pivotally secured to said base and including a depending engaging member, said actuating member being pivotable between a first position and a second position in which said actuating member lies substantially flush with the lighting track, resilient retention means mounted on said base in operative engagement with said actuating member and movable in response to the pivoting of said actuating member to a locking position in which said resilient retention means frictionally engages the lighting track and said depending engaging member of said actuator member engages the lighting track so as to retain said adapter to the lighting fixture, a stem affixed at its upper end to said base and at its other lower end to a lamp housing, locking means affixed to the lower end of said stem to restrict horizontal and vertical movement of the lamp housing, said locking means including first and second friction plates, and an actuator arm operatively connected to one of said friction plates to cause, when said actuator arm is moved from an open position to a locking position, said one friction plate to move into frictional engagement with the other of said friction plates, thereby to limit movement of the lamp housing in the vertical direction, and first and second clamp means movable upon movement of said actuator arm to its said locking location into operative engagement with said stem, thereby to limit movement thereof in the horizontal direction.