A drive screw system comprising - a stationary track, - a drive screw mounted for rotation relative to the stationary track about a screw axis, - a nut threadingly engaging the drive screw for linear displacement parallel to the screw axis in response to rotation of the drive screw, and - at least a first slide bearing for radially supporting and guiding the drive screw, the slide bearing being moveable on the stationary track parallel to the screw axis, wherein the first slide bearing is provided with - at least a first friction pad moveable relative to the first slide bearing in at least a first transverse direction transverse to the screw axis, - a second friction pad moveable relative to the first slide bearing in a second transverse direction opposed to first transverse direction, and - spring means (36, 38) biasing the first friction pad in said first transverse direction against the stationary track, and biasing the second friction pad in the second transverse direction against the stationary track; characterised in that: - the first slide bearing is provided with a first guide wall (32.5) perpendicular to the screw axis for guiding the first friction pad and preventing movement of the first friction pad relative to the first slide bearing parallel to the screw axis; - the first slide bearing is provided with a second guide wall (32.5) parallel to the first guide wall (32.5) for guiding the second friction pad and preventing movement of the second friction pad relative to the first slide bearing parallel to the screw axis; - the spring means (36, 38) includes a compression spring between the first and second friction pads for biasing the first and second friction pads in the first and second transverse directions, respectively; and - the compression spring is charged between two parallel faces of the first and second friction pads oriented such as to bias the first and second friction pads against the first and second guide walls (32.5), respectively. - a stationary track, - a drive screw mounted for rotation relative to the stationary track about a screw axis, - a nut threadingly engaging the drive screw for linear displacement parallel to the screw axis in response to rotation of the drive screw, and - at least a first slide bearing for radially supporting and guiding the drive screw, the slide bearing being moveable on the stationary track parallel to the screw axis, wherein the first slide bearing is provided with - at least a first friction pad moveable relative to the first slide bearing in at least a first transverse direction transverse to the screw axis, - a second friction pad moveable relative to the first slide bearing in a second transverse direction opposed to first transverse direction, and - spring means (36, 38) biasing the first friction pad in said first transverse direction against the stationary track, and biasing the second friction pad in the second transverse direction against the stationary track; - at least a first friction pad moveable relative to the first slide bearing in at least a first transverse direction transverse to the screw axis, - a second friction pad moveable relative to the first slide bearing in a second transverse direction opposed to first transverse direction, and - spring means (36, 38) biasing the first friction pad in said first transverse direction against the stationary track, and biasing the second friction pad in the second transverse direction against the stationary track; - the first slide bearing is provided with a first guide wall (32.5) perpendicular to the screw axis for guiding the first friction pad and preventing movement of the first friction pad relative to the first slide bearing parallel to the screw axis; - the first slide bearing is provided with a second guide wall (32.5) parallel to the first guide wall (32.5) for guiding the second friction pad and preventing movement of the second friction pad relative to the first slide bearing parallel to the screw axis; - the spring means (36, 38) includes a compression spring between the first and second friction pads for biasing the first and second friction pads in the first and second transverse directions, respectively; and - the compression spring is charged between two parallel faces of the first and second friction pads oriented such as to bias the first and second friction pads against the first and second guide walls (32.5), respectively.