Abstract: A hinge assembly for supporting the back part of a motor-vehicle seat on the fixed seat part comprises two hinges. Each of these hinges comprises a first hinge element pivotal on the seat part about a first axis between a rest position and a pivoted position and a second hinge element on the back part and pivotal on the respective first hinge element about a second axis through a plurality of angularly offset adjustment positions. Each second hinge element is provided with a plurality of teeth and each first hinge element has a pivotal pawl with teeth engageable with the teeth of the respective second element so as to hold the second element when these teeth are engaged in any of a plurality of angularly off-set adjustment positions. Mechanism is provided connected to both of these pawls for displacing the teeth thereof into and out of engagement with the respective teeth of the second formation.