The plunger used as the upper enclosure in a preparative chromatography column is suspended by one or more rods that are supported by a frame through coupling connections on the frame that can fix the position of the rod(s) relative to the frame, while the position of the rod(s) is controlled by a motorized drive system that is suspended above the column. The drive system is mounted either to the column lid or to a functional plate positioned a short distance above the column lid. These constructions allow the plunger to be raised and lowered so that the column and its parts can be exchanged, all without the need for a hoist or crane.