Its simple

Today, as I was walking out for lunch, I saw a man cutting out the weeds. But it was not a sight I was familiar with, the man was using a device which was not really a lawn mower but something simillar. He had strapped it to his back and used the handles to point the blades at the end of a protruding rod to cut the overgrown undergrowth in our campus.

It caught my attention, because in India you are used to seeing people squatting down and cutting grass with sickles. Without realizing I started to think about the design of this thing. The first thing that came to my mind was, how did the manufacturer ensure that the blades did not get damaged on contact with the ground. May be the blades are not at the tip as it appeared, but there is a small part of the rod that that prevents it from touching the ground. Something like this:
And on the way back, I found the man taking rest leaving his tool on the grass. I walked over to have a closer look and this is what I found:

(click on the image to view a larger pic)

I can't figure out why I started thinking about blades etc.. The desired outcome was achieved by using 2 wires made of hard plastic. The motor strapped at the back rotates the mantle at the tip, which in turn get the two wires into action.

The simple point is, we often complicated things where they are not required. Most problems have a simpler solution..