This BULL DOG helped me sort out a couple of patent entries for DATAMP. Not knowing Michigan geography, I had to look up Benton Harbor, Holland & Kalamazoo in a road atlas. Not real close to each other. But a patent (Mull #1,557,864) & manufacturer both in Benton Harbor strongly suggests those go together. Especially since the design in patent #1,557,864 looks like the BULL DOG wrench. That leaves HOLLAND STEEL wrench & Morris patent #1,551,763 as contemporary & possibly otherwise not related. It would not be the first time two independent inventor / manufacturer sets were developing nearly identical products at the same time.
I'd had an example of the BULL DOG in the MVWC Newsletter years ago (pg. 11, Dec. 2003 -- one had sold on eBay back then) but never looked closely at it in comparison to the HOLLAND STEEL until now.
Since Disney got Congress to re-write copyright law to generate a "perpetual" copyright starting with works "published" in 1923, anything more recent than that is harder to research using google book search because Google does not want to get sued for copyright infringement & so blocks access (except for "snippet view" and a very few publications which have signed "free to view" agreements -- like POPULAR MECHANICS & POPULAR SCIENCE