Another gear-less cam mechanism

[BillTodd]

Following on from Myrickmans discovery of the Wright gear-less cam mechanism, this is another similar mechanism I saw in Hiscox's  "Mechanical Movements, Devices and Appliances" (pub. 1899)

Here, as the worm turns the follower wheel it only operates the valve every turn.


Bill

[fumopuc]

Hi Bill, very interesting. Not so easy to manufacture. Presumably some wear but I am sure it will work in a model IC engine.

[Allen Smithee]

I'd struggle to see that as "gear-less" for two reasons:

1. It's essentially a combined cam and worm gear, so it's really just an alternative form of reduction gear.

2. To implement it you'd need either a belt or gear drive from the crankshaft to the worm/cam shaft since the camshaft has to be above the valves and it's mechanically problematic to put the crankshaft above the valve stems! You could possibly do it with a side-valve layout, but it's really too bulky to fit there.

Given that it will almost certainly need a gear/belt drive there seems to be little benefit in NOT putting the required 2:1 reduction ratio in the gear/belt system!

AS

[Allen Smithee]

Actually I suppose you *could* incorporate this mechanism into the cam followers (rather than the valve stems) of an OHV layout, but I'd still regard it as a reduction gear.

AS

[moerman]

Bill,
That is a very nice animation, did you make it yourself?

I also think it makes an engine more complicated to make than a reduction gear, but it is very inventive!

Wout

[BillTodd]

I'd struggle to see that as "gear-less" ...

Oh it is not gear less at all really, I just used that expression to link it to the Wright Bros Idea ;-)
 (I should have put gear-less in quotes perhaps)

There are many silly idea that catch my imagination - I like to try to animate them when I can

That is a very nice animation, did you make it yourself?

Yes, I've done a few over the years ;-) 

(http://wktodd.webspace.virginmedia.com/animations/  & http://www.douglas-self.com/MUSEUM/POWER/rotaryengines/rotaryeng.htm)

[smfr]

Very nice animations, Bill! I know I've run across them before seeing your links. 

Can you say a little about the tools you use to create them?

Simon

[BillTodd]

Very nice animations, Bill! I know I've run across them before seeing your links. 

Can you say a little about the tools you use to create them?

Simon

I use a combination of a 3d modeller and a photo manipulator/ gif editor.

it's really just a typical stop frame process: moving parts to where they should be for each frame . the modeller does some tweening, but is often more of a hindrance than a help.

[moerman]

The reflection on the metal, is that a result from using 3d modeller? Or do you do that in the photo editor?

[BillTodd]

The reflection on the metal, is that a result from using 3d modeller? Or do you do that in the photo editor?

I believe, the simple raytracing is done by the openGL graphics card hardware, because that file is produced from the screen output, although the software does have the option of a full software rendered o/p.

[b.lindsey]

Those are some really nice graphics Bill. If a picture is worth a thousand words, those should be worth ten thousand with the animation

Bill

[BillTodd]

Another one from the same book.

There's no indication in the patent of how the author was going to constrain the push rod while it slide side to side

ISTR Chuck(?) had built a model with a similar eccentric face cam ????

[Dave Otto]

That is very similar to what is used on the Pacific engine and it's relatives (Union, Regan, Globe, etc.). The difference is there is a shoe that runs in the track, the shoe is on a swing arm that moves the valve lifter over the cam on one revolution and away on the next.

Dave