These drives have been around for a while, after electrical service I moved onto structural steel and engineering, and in doing that I built and maintained a number of different machines in wool processing, and used electric motors with that variable drive system attached to them, to vary the speed of some of the machines.
I am blowed if I can think of the name at the moment but am fairly sure they were made in Melbourne and were completely trouble free, you changed the speed as it was running by turning a wheel attached to a worm that in turn moved the cone across the drive wheel, you could get them in a number of different sizes.
Beech.