I have an LR84 and the tines are straight in line and not offset and staggered like the one in the photo.
Beats me but it almost looks like two things clamped together?
**Edit--I'll add it is two pieces clamped together. You can see where some tines were removed and apparently bolted to a piece in front that is clamped on. Only some of the tines are actually clamped to the LR72. Lookm close.
It's an interesting design concept, however, and with thinner and sharpened tines would make a great industrial quality de-thatcher or scarifier type thing.