Recent content by gravesity

Hi Zekeman, We did choose the notch-and-constrained-actuator approach instead of the cam, because it requires far less precise alignment when we are building up the machine. But I agree with you about not ruling a good design out for lack of math. Newton didn't just work it all out for his...

Zekeman, you've outdone yourself on this one. I'll have to return to this on Monday, so it may be a while before I get a chance to validate it. Thank you for your dedication. I hope it's been fun for you. Before you go further, I have to warn you that we just decided the actuator bearing...

Zekeman, will you please upload a sketch to illustrate your terms? I'm not quite getting it. As I understand you: R is a function of @, a polar equation with its origin at the axis of rotation. Are you suggesting that w is a constant that can be eliminated between the two equations? Also...

Zekeman, thanks for the equation. I'll chug through it and see how it fits. -Simon

Yes, that sketch was simplified for clarity. If I mounted the actuator rigidly, then contact area would be chosen so that the contour is concave, rather than convex, so there would be bias against deflecting left and right. That is, of course, if everything is aligned perfectly, which would...

btrueblood, extremely astute point about balancing a ball on a ball. To build the machine like I have described it, the actuator would have to make first contact beyond the pivot axis plane, and then the always-normal contoured surface as I described it could be concave instead of convex. But...

Hello any math wizards out there, I'm designing a machine that includes a large, heavy arm which pivots on a shaft. When the unit is in operation, we hold the arm up with an electromagnet; when the magnet is shut off, gravity swings the arm down through 35 degrees until it hits a stop. To...

Hi Chicopee, This is a water turbine; the enclosure is consequently full of water splash. No need for cooling, but any lubrication effects will be bonus. Thanks!

I am redesigning a micro-hydro educational tool that is essentially a Pelton wheel runner spinning in a polycarbonate enclosure. Our current design uses a steel axle spinning inside a boss in the enclosure. We're considering changing that to a polycarbonate axle so we can reduce our part count...