Mr. Sargent's Patent Attorney's filed for the Mini-Crab's patent on May 3, 1965. The patent was granted on January 10, 1967. Click on any image to enlarge.
These are actual patent diagrams that William Sargent's Patent Attorney's drew for obtaining the patent. You can download and study the entire patent PDF (all 11 pages!) for the Mini-Crab Dolly at this link: http://www.google.com/patents/US3297337