A simple cam

[path_finder]

Dear triplock,
Many thanks for your encouragement.
The replacement of the hard shaped cam by a simple half-ellipse has been already studied several times.
One answer was here :http://www.besslerwheel.com/forum/viewt ... 8816#58816
On a strict geometrical point of view the ideal curve could be an half-ellipse as shown in this drawing hereafter:
The calculations give the exact parameters of the ellipse:
Rw is the radius of the main wheel
Rc is the radius of the left part of the cam. Rc is equal to (Rw - L -r) if L is the length of the rigid rod and r the radius of the weight).
The small axis of the ellipse is equal to Rc.
The big axis of the ellipse if equal to (Rw - 2r), in fact minus an epsilon for eliminating the simultaneous contact of the weight with the cam and the main wheel rim at 3:00.
The position of the springs center is the point S, located at the middle of the big axis of the ellipse.
For a better understanding the position B at 1:00 has been represented in grey, and the position of the weight at 3:00 also in grey.

One of the reason why I did not build this wheel, is perhaps a lack of confidence but also the more elegant design, seen here:
http://www.besslerwheel.com/forum/download.php?id=6184
where the active area is much more greater (therefore giving more power) and where no corner exist anymore in the path of the weights.
But it was perhaps a big mistake, and perhaps this design in that state (with the half ellipse) works really well. I don't know so long no model has been tested.

edited: drawing updated

[triplock]

my half circle / half oval bearing guide.

RIP.........


Chris

[path_finder]

Dear triplock,
With a deep respect, I cannot understand neither the double cage and neither the bearing.
Where is your main wheel, where are the weights and the springs?

and just a stupid question: what about a chain around the weights instead the springs?
(in violet on the picture)

[triplock]

Path-Finder,

Please find attached a photo showing an attempt, in it's simplist forms, at trying to utilise the ovals natural elongation to extend a lever arm to gain ma.

Although your design is much more deserving of acclaim, it all boils down to the same thing. The falling weight, after 3 oclock is\ having its lever arm reduced, with the up weight lever 'arm' increasing proportionately. It invariable locks off at about 45 degrees.

Also, just study the weights in their opposing pair groups, you'll see that any advantage gained at one position is immediately paid back.

IMO, the chain wrap suggested instead of springs will not overcome this fundamental problem.

But hey, what the @;./ do I know. My don't work either ;-))

Regards, Chris

[ruggerodk]

Triplock:
Are you turning it CW or CCW?

[triplock]

It turns ccw.

Pre-loaded, one weight starts at 11 oclock, and falls. The lever arm extends doing so, with the opposite arm remaining at a constant length.

Falling thru 9 0clock, the arm contracts losing lever advantage.

Due to a combination of side wall friction on the bearing race and reducing ma, it's stops at the position shown.

Chris

[nicbordeaux]

Stick an elastic band on it. And a load of WD40.

No kidding, I admire you guy's thinking and building, but sometimes I get the impression that you see one setup not work as planned, and give up on it, whereas if you know why it's failing, there is room for improvement. Let's take a simple example, you have a wheel with an elastic band, it stalls at 7 and that's it. Forget it. Whereas it might be as simple as you are using too big a mass, too strong an elastic band. Analogies, sure. And not criticism. Just an impression.

Anyhow, don't worry, I'll sell you free energy for a discount rate.

[triplock]

I'll be more happy with a 1% equity stake in the working design ;-)))

[rlortie]

Innovation to the extreme! This one is for Nick.

[AB Hammer]

Ralph

I feel sorry for the guy when he hits a pothole. He would be a real basket case.

[ruggerodk]

Due to a combination of side wall friction on the bearing race and reducing ma, it's stops at the position shown.

Dear Chris,
To me it seems more like you are trying to lift 2 weights at the same time.

In plain words: From 11 to 9 the falling weight has enough momentum to BOTH extract its own radius (actually sliding down and outward) AND lift the opposite weight.
Trough 9 it contracts and by that, it's actually BOTH falling and LIFTING itself upward and inward while - at the same time - trying to lift the opposite weight. This is going well untill around 7:30.
This is the spot where downward force equals lifting (of both weights).

regards
ruggero ;-)

[nicbordeaux]

Ralph, I do have a delivery tricycle from the 20's, but that gizmo has already been tried : the 6 wheel F1 Tyrell. As soon as it looked like winning races, the FIA outlawed it.

[path_finder]

One of the reason why I did not build this wheel, is perhaps a lack of confidence

Being frustrated by a possible enormous mistake, I decided to build the scheme.
It's not fully finished but the beast is moving with some strange convulsions.
In any case you will have tomorrow the shots and the results of my experiments (the cam today has the same shape as my avatar, then I will test the ellipsoidal shape). May be a good surprise?

[rlortie]

Path_finder,

your above depiction followed with the comment;

and just a stupid question: what about a chain around the weights instead the springs?

Reminded me of Simon Stevin's Example of why it will not work.

http://en.wikipedia.org/wiki/File:StevinEquilibrium.svg

Ralph

[path_finder]

Dear riortie,
With an excentered COG coming from the cam, some springs and the rotation, it could be different. The answer tomorrow.