I remember this lawn edger my dad used when I was a tiny kid.
allow me to describe it. I just failed my google-fu and didn't find a picture.
okay. it had a long handle with two wheels in the back. it was nothing but a platform with an electric motor on it. same motor you would find in a swamp cooler. on/off, and that is it. that motor spun a rubber V-belt, that turned a wheel. the wheel had a hub on it you could push down to install 3 metal spike things. basically the spikes were thicker than say a 16d nail with the end pointy on one end, and twisted into a hoop on the other end to clip into the hub. you would have to change spikes periodically. they would bend damn near immediately. you plugged it in to an extension cord. here is the fun part. it had a toggle switch inline on the cord hanging off the handle. you turned it on and it stayed on unless you reach down to the cord and toggle the switch.
it would fling cutting out away from you..you know for safety.
no safety cage around the spinning parts. none.
I remember my parents making me edge the yard when I was about 11. may as well make me work dynamite or a chainsaw.
you remember that edger? have a pic? I want to see if my younger brother remembers it.