Hinge joint for the seats of motor vehicles and the like

Abstract

The stationary component of a hinge joint between the lower part and the back of a seat in a motor vehicle is coupled to a pivotable component of the back of the seat by a shaft which carries an eccentric for the inner race of a ball bearing whose outer race is non-rotatably secured to a spur gear forming an integral part of the stationary component and mating with one or more teeth of an internal gear in the pivotable component. The outer race has a frustoconical internal surface engaged by the convex surface of a lever which is pivotally connected to and rotates with the shaft when the latter is turned by an operator to change the inclination of the back of the seat. An elastic pad or one or more springs are used to bias the eccentric radially of the shaft. The shaft is non-rotatably connected with but can move radially of the eccentric. The eccentric ensures that the teeth of the spur gear mate with the teeth of the internal gear without any play, and the lever ensures that the play between the teeth of the two gears is eliminated even if the tolerances in machining of these gears very in the circumferential direction of the gears.