a joint for an articulated mechanism includes a housing and a rotatable member within the housing . there is a friction member mounted on the housing between the housing and the rotatable member . there is a spring normally biasing the friction member against the rotatable member to inhibit the rotation of the rotatable member . there is an actuator within the housing operatively coupled to the housing . the actuator member moves the friction member away from the rotatable member when actuated to facilitate rotation of the rotatable member . a plurality of joints are used to connect together a series of shafts , some of which may be equipped with clamps or other tools for securing workpieces .