Abstract: A support arm system for selectively positioning relatively heavy objects such as television sets consisting of articulated forward and rear arms each comprised of parallelogram linkages which are each sprung to counterbalance the load weight. A special mounting of the forward arm springs enables a compact configuration, but which introduces slight unbalance conditions in some arm positions. An adjustable friction brake arrangement is incorporated in a pivot point of each linkage which applies a braking force to insure stable positioning of each of the arms in any position throughout the motion of the arm system notwithstanding unbalanced conditions. Also disclosed is a quick connect feature for mounting the supported load to the forward arm, which is combined with a parking lock securing the forward arm in a folded position, which parking lock is released during the connecting feature.

Abstract: An equipoising arm structure which can support relatively heavy objects, yet is compact in shape, and which can be counterbalanced by commercially available springs. The mechanism employs conventional parallelogram linkages for its lower and upper arms, with the lower arm being connected between a base bracket and a floating bracket, and the upper arm being connected between the floating bracket and a support bracket for the object. The upper arm includes a unique springing arrangement in which the ends of the springs attached to the brackets are connected beyond the conventional point of connections so as to maximize the lift of the springs when the upper arm is horizontally disposed. Means are provided for compensating for the non-linearity of such a springing arrangement over the range of angles of the upper arm that would otherwise normally occur.