Abstract: An articulation joint is disclosed for use for example on back hoe boom assemblies wherein an articulated tool arm (2) is hinged-jointed to a boom fork (1) on the boom assembly in such a manner that shocks, knocks and vibrations to which said tool arm (2) is subjected cannot to a damaging extent propagate from said tool arm (2) to said boom fork (1). To this end the bearings of the articulation joint, comprising roller bearing (5) with ball bearing (7) at either end, are via their outer bearing race (6) and possibly a circumscribed metal ring (9) held in a circumscribed elastic shock ring (8) which is suitably formed as to permit installation within the eye of said tool arm (2).