My dad and I have an old Case backhoe that we got with bad brakes. Turns out they're very similar to this design, with a ball and ramp assembly that pushes clutch discs outward into friction surfaces. A couple notable differences are that they use a a band around the disc assembly, connected to the pedal, that slows the disc assembly causing the ramps to engage. And also, they're attached to a couple of splined shafts coming out of each side of the differential, rather than on the wheels/axles. Anyway, apparently they're notoriously troublesome, and were a lot more difficult to rebuild than I would have thought.