Gearless Mechanism--4 stroke i.c. engine

[Brian Rupnow]

In the last video I posted it shows a couple of really top notch ideas that I have been wondering about. First, instead of a spring holding the gearless mechanism in contact with the cam, the large end of the rod which runs to the cam totally encircles the cam, similar to early steam engine valve rods. This means that no spring is needed. The revolving cam can now not only push the rod in it's upward travel. but also pull it back down again. Secondly, instead of some strange shaped cam, the cam is a perfect circle, simply offset by some calculated amount from the central axis of the crankshaft. And---(best of all) it has a true ratchet and pawl system to turn the ratchet wheel with a nice positive action, and then hold it by spring pressure to prevent rotational drift of the star wheel.

[Brian Rupnow]

I have decided to use the Duclos method to keep the star and ratchet wheel from getting out of rotational position. I have machined an 8 sided shape onto the side of the ratchet wheel and used a piece of .030" diameter spring wire (in red) held in place by a washer (dark blue) and #4-40 shcs. (yellow). When the ratchet wheel is forced to rotate 22.5 degrees (by a mechanism not yet shown), the wire will spring away, then snap back into place against the next flat face. The light blue "fork" that supports the star and ratchet wheel has had a small "ear" added to one side to provide a place for the #4-40 shcs to thread into. It also has a very slight groove machined into it for the .030 wire to set in to keep it from moving.

[Brian Rupnow]

To give some idea of scale, here are the parts we have been looking at with a "to scale" model of my hand.

[Brian Rupnow]

I'm getting to the "hinky" part of this design now. Assume for a moment, that the gearless mechanism has not yet stopped moving down---The star wheel is clear of the bottom of the valve-stem so it can rotate, but it hasn't rotated yet. The spring loaded pivoting "pawl arm" is swung in by the spring pushing on the back of it and you can see that the bent end of it is going to catch the tip of the ratchet wheel below the centerline of the ratchet wheel. If my downward travel is calculated correctly, then when the gearless mechanism continues it's downward travel and is fully bottomed out, the ratchet wheel and consequently the star wheel is going to be rotated by an amount equal to 22.5 degrees of rotation. --When that happens, then the gearless mechanism will move upwards due to influence from the cam, and since it has rotated 22 1/2 degrees, one of the lobes on the star wheel is going to contact the stem of the valve and lift it.---Clear so far??:eek::eek:

[Brian Rupnow]

I have absolutely no intention of building an engine for this gearless mechanism to go on. That being said, it is such an interesting mechanical device that I'm sure someone will want to build an engine to try it on. BE WARNED---This is not for any kind of high speed engine. This type of device was used on either hit and miss engines or old stationary thumpers that sat all day running about 600 to 750 rpm. I am going to do a "quick and dirty" design of a 1" bore x 1.5" stroke engine to mount it on. This will purely be a "guide" for anybody who may decide to take the design and run with it, and to give me some frame of reference for placement of parts.---Brian

[Brian Rupnow]

I suppose if it was easy, everybody'd be doing it!!! This is getting complicated----and no, I haven't shown any fins on that engine. That's why it looks so skinny.--and the head isn't on it yet.

[Brian Rupnow]

So----There we have it at about 99%. It ends up at about 10" tall, overall. The more I modeled, the more it began to look like the Philip Duclos engine. There is a good reason for that. Distance from underside of base up to center of crank has to be tall enough to allow for a flywheel. Overall cylinder length is determined by length of piston and stroke.  The carburetor/valve body has to be positioned so that it can feed directly into the cylinder head, and the length of the 4 round pillars supporting the cylinder is determined by the minimum amount of room required to fit something like the gearless mechanism into the space between the crankshaft and the stem of the exhaust valve.

[Brian Rupnow]

So, here we have it. a single cylinder four stroke engine 1" bore x 1.5" stroke, air cooled, large enough to accommodate the gearless mechanism. Again, as I said, I don't plan on building the engine, only the gearless mechanism. However, I wanted to ascertain that if someone ever actually did want to use it on an engine, it would be possible. It makes a good looking model.

[Brian Rupnow]

Someone has asked for everything I have done on this project as .stl files. You will need 3D cad software to do anything with these, and remember that nothing is proven here--it is all a "work in progress". I am confident about the gearless mechanism. The engine itself, is as I have said "Quick and dirty" but is sized to work with the gearless mechanism.---Brian
http://www.mediafire.com/download/o1x03gjh59119ak/OVERALL_GEARLESS_ON_ENGINE-X_-1.zip

[Brian Rupnow]

Not exactly huge, is it!! I wanted to make the star wheel, but didn't have any material the right size. I was able to cut this ratchet wheel from a short length of 1" diameter cold rolled.

[Brian Rupnow]

It's a cute little devil, so far.

[Tennessee Whiskey]

Brian, you're moving so swiftly the new mill must really be working out for you.  You know,  it's going so good you might as well build the engine also  .

Cletus

[Brian Rupnow]

Cletus--I don't want to get tied into another large project right now. That is why I posted a link to all of the solid models I created so others could download them and build the engine if they wanted to. The gearless mechanism is a nice little (and very interesting) project, which doesn't require a large time investment. I have been intrigued by gearless mechanisms ever since I first heard about them, and by modeling and building one I get a much better understanding of how they work. Even within the last week I have learned a lot of things about them that I never knew before. I'm not inventing anything new here----these are all tried and proven designs that I am basically gleaning from other peoples videos, etcetera and putting them into  a context I can build from. I have built enough complete i.c.engines now that I don't have any interest in building another----right now anyways!!!----Brian

[Brian Rupnow]

Okay kids and turtles!!! Some folks are asking me (I post on three different forums) why I don't build the complete engine.---I don't want to build another engine right now. There is plenty of work involved in building the demonstration model---trust me. The demonstration model will be hand cranked, but it will most definitely show the complete operation of the gearless mechanism. Note that in this model, I haven't shown the springs which hold the gearless mechanism in contact with the cam.---Brian

[Brian Rupnow]

Following my policy of "Never throw anything away---ever!!" I hunted around in a box of junk and recovered a one piece crankshaft I made a few years ago that turned out too crooked to work in an engine----But---it will work fine for a hand cranked demo model. You can see the big strange looking cam setting on one end of the crankshaft.