Angular vibration isolator for seat back

Angular vibration isolation is provided for a seat back member in combination with a mechanism for adjusting the seat back angle. Eccentrically mounted cylindrically shaped cam members located at each side of the seat back frame can be adjustably rotated within a guide channel carried by the seat back frame. The cams are positioned at a distance from a pivot axis on the seat frame around which the seat back can tilt in order to adjust the angle of tilt. One of the parallel, opposed flanges which define each of the guide channels is spaced from its respective cam member by a resilient means such as a thick pad of elastomeric material which fills the space between the cam member and said one flange. The elastomeric pads are compressed as the seat back is forced forwardly against the seat occupant's back due to vehicle vibration, thus permitting the seat back to be driven rearwardly while the occupant's position in space remains relatively fixed.