Hit and Miss push rod lifter....

[10K Pete]

Maybe that's not the right term.

I'm working through various aspects of this hit and miss stuff and, through
this board and others, have pretty much figured things out in general.

There is, however, one detail that I don't have firmly in my mind; the
various mechanisms use to 'lift' the push rod (?) to hold the exhaust valve
open. I've got the flyball governor thing but there seems to be more than
one way to actually hold open the exhaust valve.

I've read the Tiny IC thread (what a beautiful little engine!) and the way
that GaillnNM rigged it to be a hit and miss. Nice and simple. But I know
there are other ways and I'd like to familiarize myself with them.

Most photos I see don't show that detail.

Can anyone direct me to drawings or photos of ways they have done this? Maybe to posting here or on other boards? Or to on-line plans?

Thanks,
Pete

 

[Jasonb]

I took this video when I made my Galloway, shows how the weight moves the spool and then the levers that work the latch.

[ame]https://www.youtube.com/watch?v=t9bpsDyQ5D8[/ame]

This shows the method used on the Gade

[ame]https://www.youtube.com/watch?v=b3InhC_WiaI[/ame]

And the Monitor that uses a single weight that pivots from one of the spokes and pushed the "L" shaped latch

[ame]https://www.youtube.com/watch?v=qNFKEhrn0lY[/ame]

 

[10K Pete]

Jason, those are super vids! They clearly show how those machines do
that job. And it's obvious that my term 'lifter' isn't at all correct as the
mechanism is really a latch. The only one I need to study more is the
vertical engine; the flyweight seems to hit the latch arm intermitently
instead of the 'pull' of the collar mechanisms on the other engines and I
don't understand yet how that works.

Thank you for posting those, they really help me figure this out.

Pete

 

[Jasonb]

Maybe this will help

Each time the cam comes round it lifts the roller and arm to open the valve, at about the same time the pivoting weight comes round and if the engine is rulling fast enough it will lift the horizontal; leg of the "L" shaped larch which then engages with teh mating latch plate on teh rocker arm and holds it open

If the speed stays high each time the cam will lift the rocker slightly then the latch gets knocked back into the hopen position. As the speed gets less the cam will still lift but after a while the weight won't knock the latch back into place so the rocker arm drops closing the exhaust valve so you get compression and the engine fires.

Here is another of mine, sorry its sideways. This engine has a tapered edge to the spool, a roller on the end of teh L shaped latch arm runs up and down th etaper as the spool moves and moves the latch. This one is an ignitor equiped engine too

[ame]https://www.youtube.com/watch?v=tfnNj3aa8uc[/ame]

 

[10K Pete]

Yes, that pic helped! I see how it works now. The system on the vertical
engine is another way. Still a spool and flyweights but a totally different
actuator.

So it seems to me that back in the day almost anything that worked was
fair game. Probably each guy trying to establish his own patent or work
around another.

Fascinating stuff!

Thank you,
Pete