Recliner of a backrest with a locking- and unlocking device, which locks two fitting parts (10, 20) of the recliner in a locking position, wherein a worm screw having worm gearing is associated with one of the fitting parts (10, 20) and a worm wheel is associated with the other fitting part (10, 20), wherein the worm gearing meshes with the worm wheel, wherein the locking- and unlocking device has two locking mechanisms (50, 50R; 60, 60A), wherein the first locking mechanism (50, 50R), in the locking position, acts on the worm screw radially to the longitudinal extension of the worm screw, and the second locking mechanism (60, 60A), in the locking position, acts on the worm screw axially in the longitudinal extension of the worm screw, so that, in its locking position, the worm screw having its worm gearing is arranged so as to be doubly braced in the worm wheel, wherein the first locking mechanism (50, 50R) has an actuating element which acts on a radial clamping element which braces the worm screw in the locking position in a radial operative direction to its longitudinal extension, and the second locking mechanism (60, 60A) has an actuating element which acts on an axial clamping element which braces the worm screw in the locking position in an axial operative direction in its longitudinal extension, wherein the locking position of the locking mechanisms (50, 50R; 60, 60A) is effected by an operating action of an actuating member which is in operative connection with one of the locking mechanisms (50, 50R; 60, 60A), and the unlocking position of the locking mechanisms (50, 50R; 60, 60A) is effected by an operating action which is the reverse of the operating action of the actuating member in the locking position, characterized in that the actuating elements (50, 60) in the locking position are arranged with play relative to one another, wherein the actuating elements (50, 60) have noses (50.1, 60.1) which, in the locking position, are arranged with play relative to one another, wherein the play is only abolished when the actuating elements (50, 60) are actuated by means of the actuating member into the unlocking position, since the locking- and unlocking device has an actuating member which is in direct operative connection with one of the actuating elements (50, 60), so that the actuation of the actuating member from the locking position into the unlocking position leads to an actuation of the actuating element (50, 60) in direct operative connection with the one of the actuating elements (50, 60) leads to an indirect entrainment of the other actuating element (50, 60), wherein the indirect entrainment of the other actuating element (50, 60) is effected by overcoming the play between the noses (50.1, 60.1) of the actuating elements (50, 60), wherein the actuating elements (50, 60) are eccentric elements, the eccentric regions of which act on the clamping elements (50R, 60A) during the actuation by means of the one operating action of the actuating member from the unlocking position into the locking position, wherein the locking position of the clamping elements (50R, 60A) is adjusted by the eccentric elements independently of one another in the radial and axial direction (R, A) to the longitudinal extension of the worm screw, wherein locking forces are generated which, viewed from the longitudinal extension of the worm screw, act on the worm screw.