| a pair of hoisting drums of different diameter turning at the same rate, such that a pulley suspended below them on a line wound on the larger drum and unwound from the smaller drum is raised with mechanical advantage. |
differential windlass  (click for larger image in new window) n. A hoisting device that has two drums of different sizes on the same axis. A line wound on the larger and unwound from the smaller drum provides extra lifting power. Also called Chinese windlass. |