I wouldn't say its impossible to use a Landscape Rake on grass, but I'd get one with gauge wheels, and start out on a part of the lawn you didn't mind tearing up.
Speaking from experience.
I had to take my son to work today, and noticed a "Clearance" sign in back of the TSC store, where all their implements are kept. They had their 6' King Kutter landscape rakes marked down from $470 to $350, so I bought one.
Charles, you're probably right. I noticed how heavy and stiff the tines are on landscape rakes. But if it doesn't work out for that purpose, I can use it for other projects around the place. I've seen on other threads where Leinbach makes a Pine Straw Rake, which they say is good to use on grassy areas for picking up small limbs & debris. So I may get one of them or else try to make something. If I made it though, it wouldn't be pretty.
RBD, I was going to hold out for a Fred Cain rake because I like the looks of the heavy tubular frame better, but I couldn't pass up a deal like that.
I bought mine at the TSC in Longview, but there may also be clearances in the TSC stores in the Beaumont area, too.
Ronnie