A light supporting frame and a carriage therefor mounted for vertical movements on a hollow tower having an upwardly tapering hollow base which contains a power operated winding drum on which is wound a pair of frame and carriage supporting cables. A transverse support arm extends in opposite directions from the top of the tower. Cooperating latch and strike elements releasably lock the light supporting frame to the transverse support arm, and latch releasing devices are carried by the frame and carriage. Tower engaging stabilizers on the frame and carriage hold the same against lateral movement relative to the tower. The winding drum is provided with an automatic brake to stop rotation of the winding drum when power is cut off therefrom.