Hammer

This is a picture of a helve-hammer. A foot operated hammer. I want to make one like it. Details that I really like....the foot pedal is a round ring, not so likely to hurt my shin if I walk too close to it. The link between the hammer and the foot lever seems almost infinitely adjustable. The springs can be tightened up if desired, and more can be added if necessary. The whole hammer can be raised a few inches in back. (Though I don't know why....) And I believe the big 6 inch pipe under the anvil can be filled with sand to soak up the blows, and protect the floor.
Things I don't like about this hammer design...
I don't know how I would change anvils. Some of the anvils I use are not metal anvils at all, but rubber, sand bags, or wood blocks. Not sure how adaptable this set up is to swop out anvils. I would like to see a safety stop, where if I suddenly leaned back, a prop would drop in and keep the anvil up and out of harms way. Or maybe a high tech laser/photocell which would do the same. I saw one of those once to keep fingers out of a punch press, and again, to keep fingers out of the blade of a table saw. The distance between the arm and hammer face is a little short for comfort. I would like a longer hammer head to clear edges of metal.
I like the idea of the foot operated hammer. A little safer than a power hammer.

Sort of thinking about hammers this morning...and the arthritics in my shoulder.