I sent this message to Carl Harris, but it kicked back to me as unsendable. Maybe he will see it on this forum, or maybe it will be interesting to some other collector. If it's old news, my apologies.
"Carl ââ,¬â€œ Iââ,¬â,,¢m a relative new-comer to the Cletrac business and have just recently purchased a 20-K. In my general enthusiasm I have spent much time looking at the Cletrac.org web site and have learned a great deal. I got a repro parts book from Zimmerman and was interested to see the list of patents by Cletrac. I got on the official web site for U.S. Patents and started looking them up. I got down to patent number 1,641,331 and when I saw the drawings it rang a bell about one of the String of Pearl tractors from the Cletrac site. I went back and found your different model F with the extra wheel, and it looks a lot like the one in the patent. If this is already old news to you, forgive my enthusiasm. If it is not, take a look on the site at:
http://www.uspto.gov/index.html (http://www.uspto.gov/index.html).
The full link for the image Iââ,¬â,,¢m talking about is:
http://patimg1.uspto.gov/.piw?docid=US0 ... PN/1641331 (http://patimg1.uspto.gov/.piw?docid=US001641331&SectionNum=2&IDKey=F788EE814957&HomeUrl=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1%2526Sect2=HITOFF%2526d=PALL%2526p=1%2526u=/netahtml/srchnum.htm%2526r=1%2526f=G%2526l=50%2526s1=1641331.WKU.%2526OS=PN/1641331%2526RS=PN/1641331).
Thanks for reading my ramblings. ââ,¬â€œ Jack Janzen"
I see it was invented by Jim Heaslet. He invented many things for Cletrac. I believe my Gramps worked with him.
I guess the fact that there is a patent for a design like Carl's "string of pearls" model F doesn't mean that his is not a one-of-a-kind machine. It still might be the only one built by the company to test the design.
There is a model F, owned by a collector in the Cleveland area, that has two different track frames - the right is different from the left. I believe I saw it many years ago and don't remember the details, but it may have one like Carl's on one side. Not sure of the other side.
Blake