A pole shaft is provided with continuous loop drive chain means to raise and lower a luminaire ring assembly mounted thereon. A detachable fixed head assembly is provided at the top of the pole shaft and has locating and locking means for fixedly retaining the luminaire ring in its fully raised position. The detachable fixed head assembly is provided with radially extending support arms having sheaves which support lifting and lowering suspension cables that engage the luminaire ring. The suspension cables extend inside the pole shaft and operatively engage a transition plate provided in association with the continuous loop drive chain means. A motor drive assembly is provided in the base of the pole shaft which operates the continuous loop drive chain means and associated limit switch positioning means which control the amount of travel of the continuous loop drive chain. A safety lock assembly is provided on said transition plate so as to selectively engage a safety cable provided in the pole shaft in the event of failure of the continuous loop drive chain.