Some kind of vetch, maybe. Hairy vetch has purple flowers.

Interesting observation. I would like to know too.
I don't know the name but they grow as "weed" everywhre around her.
But the beans are tiny, although edible.

It looks like one of the vetches, which are legumes. Vetches are used as forage, fodder, ground cover and green manure crops.

Jim

Here is a link that might be useful: Vetch Images

Yep, it's a vetch. They can grow wild and are considered to be a weedy pest in some places, while others buy vetch and plant it. It's good for preventing soil erosion, and I think for an addition to cattle feed as Jim says. Since it is a legume, it's also used sometimes for its nitrogen-fixing characteristics, then plowed under.