Identifying Farm Implement?

From what I can see from the picture the triangle piece you are asking about does not look like it could be used to dig or even cut with because it really looks way to thick. This looks more like a piece that belonged to another piece of equipment that was used as a stand to help support the blade when it was in the sitting position. There are many images of hand does and machines that tuned the ground for planting. Each time you look at one of these pieces of equipment there is a piece such as you are asking about that was in the middle of the arm that they could put the plow down and it would not fall over.