Hinge fittings for seats with adjustable back rests

Claim 1

A HINGE FITTING FOR A SEAT WITH AN ADJUSTABLE BACK REST, ESPECIALLY FOR MOTOR VEHICLES, COMPRISING A FIRST HINGE MEMBER ADAPTED TO BE SECURED TO ONE SIDE OF THE BACK REST, A SECOND HINGE MEMBER ADAPTED TO BE SECURED TO THE SAME SIDE OF THE SEAT AND INCLUDING A PAIR OF MEMBERS ADAPTED TO BE CONNECTED TO EACH OTHER TO FORM A CASING, SAID FIRST AND SECOND HINGE MEMBERS BEING PIVOTABLY CONNECTED TO EACH OTHER, A FIRST CONICAL LOCKING MEMBER NONROTATABLY MOUNTED IN SAID SECOND HINGE MEMBER AND HAVING A FIRST SET OF TEETH ON THE CONICAL PART THEREOF, A SHAFT ROTATABLY MOUNTED IN SAID FIRST LOCKING MEMBER AND HAVING ON ITS PERIPHERY A SECOND SET OF TEETH, A TUBULAR SECOND LOCKING MEMBER MOUNTED ON SAID SHAFT SO AS TO BE MOVABLE IN THE AXIAL DIRECTION THEREOF AND HAVING ON THE WALL OF ITS BORE A THIRD SET OF TEETH ENGAGING WITH SAID SECOND SET OF TEETH ON SAID SHAFT SO THAT SAID SECOND LOCKING MEMBER IS NONROTATABLY MOUNTED ON SAID SHAFT, SAID SECOND LOCKING MEMBER HAVING AN INNER CONICAL SURFACE PROVIDED WITH A FOURTH SET OF TEETH ADAPTED WHEN SAID SECOND LOCKING MEMBER IS SHIFTED IN THE AXIAL DIRECTION TO ENGAGE WITH OR DISENGAGE FROM SAID FIRST SET OF TEETH ON SAID FIRST LOCKING MEMBER, SAID FIRST SET OF TEETH ON SAID FIRST LOCKING MEMBER AND SAID FOURTH SET OF TEETH ON SAID SECOND LOCKING MEMBER HAVING SUCH A SHAPE THAT THE PLANE OF EACH OF THEIR TOOTH FLANKS IS INCLINED RELATIVE TO THE AXIS OF SAID SHAFT AT A MAXIMUM ANGLE OF