Drum 1 rotates about fixed axis A-A. Chain sheave 3 has a spiral conical groove and rotates about fixed axis B-B. One end of chain 2 is secured to drum 1 at point C and the other end to sheave 3 at point D. When drum 1 rotates at uniform speed, chain 2 is wound on the drum and unwound from sheave 3 which rotates at variable (gradually decreasing) speed.
$3488$SFL,4L$