Rapid attach and release clamps for attaching to supports include a threaded rod, an arm pivotally attached to the threaded rod, and a knob having an exterior surface and an interior surface. The knob defines a passageway sized to fit the threaded rod. A lock comprises at least one thread and is rotatably attached to the interior surface of the knob. The lock is constructed and arranged to move between a closed position with the thread entering the passageway and engaging the threaded rod and an open position with the thread not entering the passageway. A lever is moveably attached to the clamp and constructed and arranged to rotate the lock about a pivot point.