<p>The carriage (1) has a beam (3) pivoted at the center and a lever (8) pivoted at one end. An adapter element (10) is fastened to the beam and carries a further adapter (11). The system includes an angled drive adaptor (7). The carriage can fit in a groove in the door- or window-frame with the adapters adjusting the position of the wheels with respect to the frame.</p>
