The Australian patent bestseller has located is No. 29516 of 1957.
A PDF copy is attached below.
It's clear from the description that this used a friction drive from the blade disc. However, it sure looks like a gear in the drawing!
But it would appear that the edger design for the Victa Model 5 may have been a bit different, as the one described in the patent had an outrigger bearing at the outer edge of the deck. It would have needed quite a big cutout in the deck to accommodate the edger blades, too.
It would be most valuable if bestseller has info on the final edger design, for which the Model 5 deck was originally cast.
Cheers, Gadge
"ODK Mods can explain it to you, but they can't understand it for you..."
"Crazy can be medicated, ignorance can be educated - but there is no cure for stupid..."
