WINDOW LIFT MECHANISM

A window positioning apparatus for a vehicle comprising a window panel, a frame in which the window panel is guided between a closed position closing a window opening in the frame and an open position opening the window opening, and a multi-stage telescoping screw actuator mechanism connected between the window panel and the frame, the actuator mechanism being extendible to move the window panel from its open position to its closed position and collapsible to move the window panel from its closed position to its open position. The multi-stage telescoping screw actuator mechanism includes a plurality of screw members of progressively decreasing diameter respectively telescopically disposed within a next adjacent screw member of larger diameter. The plurality of screw members includes a first stage screw member that is rotatably supported and axially constrained in a housing fixed with respect to the frame, a last stage screw member attached to the window panel, and at least one intermediate stage screw member, and each intermediate stage screw member has internal and external threads respectively for engaging external and internal threads on next adjacent screw members, such that rotation of the first stage screw member in a first direction relative to the last stage screw member will cause the intermediate and last stage screw members to extend telescopically along an extension axis from the first stage screw member and rotation in a second direction opposite the first direction will cause the intermediate and last stage screw members to telescopically retract.