The handle is simply a hollow tube, and a rather beefy one at that. At the control valve end of the handle, a pin is situated across the hollow area. The pin actuates the valve by rotation of the handle.
A model SJ-23 with a jointed yoke does have a control knob with an associated actuation rod. Illustrated parts diagrams even suggest that this jack should have a control knob with an actuation rod. However, in my experience with these, all 1.5 ton units with a solid yoke were not configured this way.