Seat back hinge mounting for a forwardly foldable motor vehicle seat

1. A seat back hinge mounting for a forwardly foldable motor vehicle seat comprising: a first hinge arm and a second hinge arm adapted for relative rotation about a hinge pin, a locking cam, which is disposed on said second hinge arm and is movable between a locking position and a release position, a first stop flange and a second stop flange being provided on said first hinge arm and said locking cam cooperating with said second stop flange in the locking position and does not cooperate with said second stop flange in the release position, wherein

a retainer lug, which is bound in a circumferential direction by said first stop flange and by said second stop flange, is provided on said first hinge arm;

a limit stop cooperating with said first stop flange and being spaced in a same radial distance apart from said hinge pin as said first stop flange is disposed on said second hinge arm; and

a retainer device that prevents said locking cam from moving from the release position into a forbidden region defined by an area bounded by (i) an arc of a circle about said hinge pin having a radius extending from said hinge pin to a free end of said retainer lug, (ii) a line extending from said hinge pin to said limit stop and (iii) a second line extending from said hinge pin to said first stop flange.

2. The hinge mounting as set forth in claim 1 , wherein, if the locking cam is in the locking position, a distance measured in the circumferential direction between the first stop flange and the second stop flange of the retainer lug corresponds to a distance between the locking cam and the limit stop.

3. The hinge mounting as set forth in claim 1 , wherein a spring is associated with the locking cam, said spring elastically biasing the locking cam in the locking position.

4. The hinge mounting as set forth in claim 1 , wherein the locking cam is disposed on the second hinge arm so as to be pivotal about a cam axle.

5. The hinge mounting as set forth in claim 4 , wherein the cam axle is spaced a greater distance apart from the hinge pin than the free end of the retainer lug.

6. The hinge mounting as set forth in claim 5 , wherein a disengagement lever is provided on the seat back and that there is provided a slaving means connecting the disengagement lever to the control arm.

7. The hinge mounting as set forth in claim 1 , wherein there is provided a control arm disposed on the second hinge arm so as to be pivotal about a control arm axle and comprising a control region and that a slaving region cooperating with said control region is formed on the locking cam.

8. The hinge mounting as set forth in claim 1 , wherein the retainer device comprises a control arm and a retainer arm.

9. The hinge mounting as set forth in claim 1 , wherein the retainer device retains the locking cam in its release position.

10. The hinge mounting as set forth in claim 1 , wherein there is provided a round member that is interposed between the first hinge arm and the second hinge arm, the round member comprising: (a) a first round plate connected to the first hinge arm; (b) a second round plate associated with the second hinge arm; (c) a clamp forming a partial grip around a rim of the two round plates to hold them together; and (d) a stop device located between the two round plates.

11. The hinge mounting as set forth in claim 10 , wherein the clamp comprises a cutout for a stopper nose to extend through.

12. The hinge mounting as set forth in claim 1 , wherein there is provided a plate that is connected to the second hinge arm and has a window as well as an opening for the retainer device.