Sorry this took so long, Chris. I had the builder's plate on my home laptop, which for some reason decided to download new system software and delete everything in my documents and pictures folders, along with the desktop, all of my solid model files, and the 3d printer software I'd downloaded. I'm now finally getting to the documents and photos, which I had backed up. Attaching them below...I hope. I also lost the MS-Paint application which I could use to resize the photos. IF they don't come through I will bring them in to work on Tuesday and try uploading them again.
Below, the first photo should be the builder's plate for the cable-driven shovel (SPEEDER MACHINERY CORPORATION CEDAR RAPIDS IOWA) and a list of patents, the last of which might put an earliest date on the rig - US Pat. 1753567 or possibly 1753367. Hmm, google patent search doesn't make sense for either of those, but the 1753xxx to 1758xxx patent date range is the 1930's, so it's sometime after that.
Also the bucket has a builder's plate, second picture below - PETTIBONE MILLIKEN CHICAGO ILLINOIS. And what I think read "1.38 YARDS CUBIC CAPACITY"
Ok, the pictures are not going thru, will try again on Tuesday.