Crank Substitute Engine
Like the Coomber, this engine also came from Marlyn Hadley’s wonderful book.6I can do no better than to quote him:
“This elaborate arrangement of gears and linkages enabled the builder to eliminate the crank as we know it. While this engine required more labor to construct, it did make a compact engine which did not require a heavy crosshead as the connecting rod connection on the bar between the two gears moves but a very small amount. This means the piston rod guides can be made of a lighter construction.
I do not know who invented it, when, or what prompted the inventor to think this arrangement is better than a crank…”
A few visitors have noted that there was actually a patent on the crank mechanism in the very early days of steam technology. This may have been the reason for the oddball design, but I still don’t have a definitive source of information. If anyone knows of a good book on the subject, please email me!