A pivoting support assembly with a selective position locking capability may comprise a base, a first support arm movable with respect to the base, a first pivot joint pivotally mounting the first support arm to the base, and a first position locking assembly configured to lock a selected position of the first support arm with respect to the base. The first position locking assembly may comprise a first hydraulic motor mounted on the first pivot joint and having a fluid input and a fluid output with a fluid path defined therebetween such that fluid movement on the fluid path between the fluid input and the fluid output operates the first hydraulic motor. The first position locking assembly may comprise a first lock valve in communication with the first hydraulic motor and configured to selectively block fluid movement through the fluid path of the motor.
