What is this part on the eccentric?

[10k]

Does anyone recognize the screw / oiler / whatever that's on the eccentric on this Robertson Semi-Rotary Steam Engine? It's to the left of "H" on the eccentric. I think it may be there to allow you to reverse the direction of the engine. Perhaps there are two indentions on the crankshaft at 90 degree offsets? I don't think it's an oiler - it's in the wrong place.

Note that the eccentric linkage can be disconnected from the rocker arm "I" near "B" by using the handles. The original description says "The eccentric rod is hooked to the rocker arm I, the latter being provided with a handle, whereby to operate the valve by hand when starting the engine."

Maybe you disconnect the rocker arm, rotate the eccentric on the shaft, then operate the steam valve by hand to get the engine realigned?

Any ideas?

-10k

 

[RonGinger]

There were a number of steam engines, particularly very big ones, that had a handle like that. The operator lifted the rod off the pin and manually rocked the valve back and forth until he had enough momentum, then dropped the handle onto the pin. Very big beam engines worked that way as well.

A couple of the big Corliss engines at the New England Museum of wireless and steam are operated that way, and will be in action next weekend for the annual Yankee Steamup.

There is a locomotive in Maine, the LION, that operated that way with two cylinders. The engineer stood and operated the valves until he was going the way he wanted, then dropped the links onto the lever from the eccentric. Its on my list of models I really want to make.

The pin by H appears to be part of the mechanism to set the clearance between the strap and the eccentric to allow for wear and still keep it tight to prevent slack.

 

[ausdier]

Looks like it is just an oiler ?

 

[10k]

Thanks for the info on the linkage disconnect.

Regarding the bolt shaped thing on the eccentric - I don't think it's an oiler. The part is on the eccentric. The eccentric rotates with the flywheel and the crankshaft. Why would you attach an oiler to a part that rotates? Wouldn't it just sling out all the oil?

I think that it's something else. I just don't know what.

 

[GYoung]

Just looks like a collar with set screw. Purpose--

 

[GYoung]

Just looks like a collar with set screw. Purpose--it is part of the eccentric, used to position it on the shaft. Instead of putting a set screw into the eccentric, which usually comes in at a diagonal from the side or straight through the eccentric's groove to the shaft, they just machined a collar and set screw hole as part of the eccentric. Six of one, half dozen of the other in a way to fasten the eccentric to the shaft.

 

[Jasonb]

Pat Jorgensen did have quite a bit about this engine on his website, His father has made a model of it and he had a lot of it drawn up in CAD but I can't locate the thread at the moment.

His farthers original sketches are still in the download section

http://www.homemodelenginemachinist.com/downloads/robertson-semi-rotary-steam-engine-195.html

There is also a short clip of it running on youtube

J