Hi, your design is great. The sides of the dustpan will get chewed up quick by a big horizontal spinner, you may be better with just a sharp flat plate/wedge that stuff rides up onto and gets clamped. Sort of like a wedge with a clamp arm sticking up out of it. The setup will work a lot more naturally.

Sort of a bit more like this type of shape. If you look closely, there is a vertical wall at the end of the wedge to stop the horizontal spinner blades without damaging the grab/crush arm.

http://vignette4.wikia.nocookie.net/...20130920120304