Hello Ballarinelawns
I can assist here, because I have met the engineers who designed it!
It may come as a shock but this is not a scarifier.
It is a flail mower, designed, manufactured and sold by Rover
for a couple of years.
In the early eighties, flail mowers were the rage.
Their main selling feature was that they deflected projectiles downward,
rather than outward, making them popular for roadside work.
Flail mowers are still sold today.
Unfortunately the Rover Flail never sold.
Expensive to make, it could not dent the sale of the traditional
rotary slashers.
These are rare machines, and this one is in great condition.
I hope you acquire it for your collection, and give us a
photo record of its design.
Nothing has been written about them, apart from what I have said
here. An exciting find in my books.
Hope this helps.
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Jack.