Adjustable backrest mechanism

Claim 1

A SEAT, PARTICULARLY A MOTOR VEHICLE SEAT, COMPRISING A SEAT PORTION; A SEAT BACK HAVING SUPPORTING FRAME COMPRISING TWO SPACED APART SUBSTANTIALLY UPRIGHT MEMBERS AND A TUBULAR CROSS MEMBER CONNECTING SAID SUBSTANTIALLY UPRIGHT MEMBERS IN THE REGION OF THE LOWER ENDS THEREOF; PIVOT MEANS COAXIAL WITH SAID TUBULAR CROSS MEMBER FOR MOUNTING THE LATTER TURNABLY ABOUT ITS AXIS SO THAT SAID SEAT BACK MAY BE TURNED RELATIVE TO SAID SEAT PORTION BETWEEN A SUBSTANTIALLY UPRIGHT POSITIONS AND A PLURALITY OF REARWARDLY INCLINED POSITIONS, SAID PIVOT MEANS COMPRISING A HINGE FITTING ON ONE SIDE OF SAID SEAT PORTION AND INCLUDING AJUSTING AND RELEASABLE LOCKING MEANS FOR ADJUSTING THE POSITION OF SAID SEAT BACK RELATIVE TO SAID SEAT PORTION AND FOR LOCKING SAID SEAT BACK IN ANY ADJUSTED POSITION,, AND A SIMPLE PIVOT BEARING ON THE OTHER SIDE OF THE SEAT PORTION; AND A SINGLE LOADING SPRING IN SAID TUBULAR CROSS MEMBER AND COOPERATING WITH THE LATTER TO BIAS THE SAME IN ONE DIRECTION TO AUTOMATICALLY TURN SAID SEAT BACK IN SAID ONE DIRECTION UPON RELEASE OF SAID LOCKING MEANS.