Abstract: A bidirectional transfer mechanism is provided for independent or simultaneous X-axis and Y-axis precision displacement of a mobile component, such as a video cassette pick-up unit for retrieving or returning video cassettes from a cassette library. The transfer mechanism comprises an upright column assembly supported on a machine frame for X-axis displacement and carrying the pick-up unit for Y-axis displacement. A first drive cable is connected to the upper and lower ends of the column assembly and threaded over a first set of pulleys on the machine frame, with a portion of the first cable being wrapped about a motor-driven winding drum for displacing the column assembly in the X-axis direction. A second drive cable has a portion thereof wrapped about another motor-driven winding drum and is threaded about a second set of pulleys on the column assembly and the pick-up unit, whereby drum rotation displaces the pick-up unit along the column assembly in the Y-axis direction.