Seat reclining mechanism

A seat reclining mechanism comprising:

• first and second hinge plates for mounting on a seat and a backrest respectively, said first and second hinge plates in rotatable contact with each other;
• a pair of internally toothed ring gears spaced axially apart from each other, one of said internally toothed ring gears being carried on one of the hinge plates and the other being carried on the other of the hinge plates, one of said internally toothed ring gears having more teeth than the other ring gear;
• a shaft extending through said pair of ring gears;
• a drive gear being in the space within said pair of ring gears, said drive gear being mounted on said shaft;
• a plurality of planetary gears in mesh with both of said ring gears and said drive gear;
• a pair of carrier members each having a central aperture complementary to said shaft so that said shaft can rotate within each of said carrier members, said carrier members each having a plurality of partially circular, equiangularly spaced openings thereby providing a plurality of radially extending arms with substantially concave surfaces extending between neighboring arms, each of said carrier members being at an opposite side of said drive gear with each of said planetary gears snugly received between neighboring arms and in contact with said concave surface, said concave surfaces constructed to urge said planetary gears into mesh with said ring gears;
• and
• means to rotate said shaft and said drive gear to effect relative angular adjustment of the two hinge plates through concurrent meshing of said planetary gears with both of said ring gears.