Abstract: The belt or belts of a passive vehicle occupant restraint belt system are moved from a restraining to a releasing position by a motion transmission system which transmits opening motion of a vehicle door to a belt transfer guide and includes a motion amplifier, the output of which drives the guide, and a folding linkage which remains folded and transmits door motion to the motion amplifier input device when the door moves between the closed position and a partly open position and unfolds and substantially ceases to transmit door motion to the motion amplifier when the door is moved between partly and fully open positions.