Posted 7 years ago
Jacobwaco
(5 items)
What is it? Its really heavy, big, cool. Thanks for your help! My imagination tells me it could be used to tighten tracks on a tank? All I can find about Duff relates to jacks and this seems to be an antijack.
https://www.google.com/patents/US2771787
Similar models made by simplex.
Modern versions are advertised as useful tools for welding shops, likely to hold material together while welding or spread parts?
Update 11/25/18: it is a sill straightener patented by Duff Manufacturing in 1923-1925. Google Patents: Sill Straightener.
Thank you bobby725 for the info, I never imagined it would be related to logging. Do you have a guess as to what time period it is from? Thanks again for taking the time to help.
They make such a thing to join long sections of pipe which need to be tightened together or slid into a coupling. Clamps are put around the sections to be joined and the tool is hooked onto specially designed surfaces on the clamps and cranked together.
The moveable parts can also be reversed on the threaded rod to work in the opposite direction.
Thank you UncleRon! Do you imagine it has a specific tool name? Thanks for sharing your knowledge.
I think it's Bob. No, seriously, I have no idea. If you haunt the plumbing /construction tool sites you may find it. If my guess is correct I think it would be for fairly large pipe - say three or four inches, or more.
Haha, thanks UncleRon. I'll update here if I find more information.
I have concluded that the official term is Push Pull Screw Jack. I have found models made by Simplex that appear to be more recent. I cannot yet locate any reference of this model by Duff. I found a patent that is attributed to Duff Norton around 1955 for a more advanced version based on the same principle. https://www.google.com/patents/US2771787
I assume this is pre 1955.
Will update as I learn more!
I have solved the mystery through patent research. Thank you everyone for your advice and interest.