Abstract: An adjustably lockable hinge for motor-vehicle seats comprises first and second hinge elements and a pintle between these elements defining a pivot axis therefor. A first arcuate row of equispaced first abutments is carried on the first element spaced from the main axis and facing axially in one direction. A body carrying a second arcuate row of equispaced second abutments facing axially from the body opposite to the one direction and axially aligned with the first row is rotationally linked to the second element. The abutments of the second row are spaced apart by a predetermined distance different from the spacing between the first elements, so that only a limited number of the second abutments can mesh at one time with the first abutments. An adjustment device rotatable about the axis relative to the elements is engageable with the body for precession of the second row on the first row. These rows may be annular arrays of gear-type teeth and the body may be a ring around the hinge pintle.

Abstract: A first mounting member can be secured to a backrest member of a seat, such as a seat of an automotive vehicle, and a second mounting member can similarly be secured to the seat member of the seat. A ring gear is provided on one of the mounting members and has inwardly directed teeth, and the other mounting member has a spur gear received within the ring gear and having outwardly directed teeth which mesh with play with the inwardly directed teeth. The spur gear has an outer diameter smaller than the root diameter of the ring gear by at least the height of one tooth and the number of inwardly directed teeth is different from the number of outwardly directed teeth by at least one. An eccentric arrangement is provided, extending through the gears and being movable to and from a position in which it effects relative radial displacement of the gears to such an extent as to eliminate the aforementioned play.

Abstract: A pair of hinge fittings is mounted at opposite lateral sides of the seat. Each fitting includes a first strap that is fixedly connected with the seat member and a second strap that is fixedly connected with the back member. A pivot connects the straps of each for relative pivotal movement. One strap of each fitting carries an arcuate gear segment and the other strap carries an engaging member which is permanently biased into engagement with the respective gear segment by a biasing spring. A control arrangement is provided which permits the engaging member to be moved out of contact with the respective gear segments. This control arrangement includes on each fitting a pivotal first arm that can be moved into and out of engagement with the respective engaging member and, when it is in such engagement, prevents the engaging member from moving out of engagement with the gear segment.