A reclining device engaged on a vehicle seat, the vehicle seat having a seat back and a seat cushion, the seat back adjustably inclinable by the reclining device with respect to the seat cushion, said reclining device comprising:
- a movable plate means fixed to said seat back;
- a base plate means fixed to said seat cushion;
- a shaft means having a first end connected rotatably to either said movable plate means or said base plate means and a second end secured to the other of said movable plate means or said base plate means;
- said movable plate means being rotatable about said shaft means with respect to said base plate means;
- a first lock gear means in either said movable plate means or said base plate means at a point to which said first end of said shaft means is rotatably connected;
- a second lock gear means which is slidably fitted about said shaft means such as to be slidingly movable in a longitudinal direction of said shaft means and thereby be brought to a meshed engagement with or disengaged from said first lock gear means;
- both said first lock gear means and second lock gear means being interposed between said movable and base plate means;
- an elastic biasing means disposed between said second lock gear means and one of said movable plate means on said base plate means, said elastic biasing means being for biasing said second lock gear means towards said first lock gear means, to thereby normally keep the meshed engagement therebetween;
- a lever means;
- an interlocking means provided between said second lock gear means and said lever means, said interlocking means including:
- (a) a slide guide means which is so disposed between said movable plate means and said base plate means as to be rotatable relative to a central axis of said shaft means, said slide guide means being connected to a base end portion of said lever means, said slide guide means being formed with a first helical guide hole and a second helical guide hole at opposite sides of said slide guide means, said first helical guide hole having one end area from which other remaining area of the first guide hole extends helically along a peripheral wall of said slide guide means, whereas said second helical guide hole has one end area disposed in alignment with said one end area of said first helical guide hole, other remaining area of said second guide hole extending helically in an opposite direction to said other remaining area of said first guide hole, along a peripheral wall of said slide guide means, said other remaining area of each said first guide hole and second guide hole being oriented in a same direction away from said direction in which said second lock gear means is biased to the meshed engagement with said first lock gear means;
- (b) a slider means integral with said second gear means, said slide means being slidably fitted about said shaft means and having a securing hole perforated therein;
- (c) a pair of elongated guide holes which are formed on opposite sides of said shaft means, said pair of elongated guide holes extending along the longitudinal direction of the shaft means;
- and
- (d) a guide means which is inserted through said first helical guide hole, said second helical guide hole, securing hole and pair of elongated guide holes,
- wherein a vertically rotational operation of said lever means produces a horizontal or lateral displacement of said second gear means, against a biasing force of said elastic biasing means, in a direction to be disengaged from said first gear means.