The stopper component of a swivel joint, for example, can be formed on the inner circumference of the outer bearing component. The stopper component is engaged in a locking manner corresponding to at least one groove-like depression on the outer circumference of the bearing component, within a specific adjustment position. Relative to this depression, particularly to the depression located on the outer circumference of the swivel joint bearing component, the stopper...PartAdopt pre-set positions or orientations, particularly the end positions when the cushion is in a horizontal or vertical position.It is also the end position of the rotatable bearing component of the swivel joint. The stop component located on the outer surface of the bearing component of the swivel joint forms, for example, a deformable thickened portion of the material or, for example, a rib.