Gallery, Projects and General > The Design Shop
Second post and already I need help
BillTodd:
Does the idler do anything other than connect the crank and rollers? (does it drive anything else?)
If not, then the the speed of the rollers is set by the size of the Crank gear and the Roller gear - the idler size does not effect this.
You've pushed the crank to the left by a couple of inches, so the idler has to be a couple of inches bigger (roughly) to fill the gap between the crank and roller gear. The idler will revolve slower for a given crank speed, but it will not change the speed of the roller.
If you have room, top & bottom, for the bigger idler gear the it seems like the simplest solution.
AdeV:
Ed,
All the idler is doing is transferring drive from one wheel to another, and reversing the rotation. It can be any size, because it transfers exactly the same "number of teeth of rotation" from the drive wheel to the driven wheel.
Consider:
Imagine your drive wheel has 100 teeth, and your driven wheel 50. So the driven wheel goes around twice for every rotation of the driver.
Now put an idler gear in, with 100 teeth. Every single rotation fo the driving wheel will turn the idler once. As the idler has 100 teeth, it will turn the driven wheel twice for every rotation - i.e. the same as if it were being driven directly.
Now put a 50 tooth idler in; the driver will turn the idler around twice for every single rotation; but the idler will only turn the driven wheel once for each of it's rotations: i.e. your 1:2 ratio is preserved.
Now put a 500 tooth idler in. The driver must turn 5 full rotations to make the 500 tooth idler turn once. And every single rotation of the idler will turn the driven wheel 10 times (500:50). So 5 turns of the driver = 10 turns of the driven, 2:1.
It doesn't matter how many idlers you put between driver & driven, or what size they are, they ratio of drive to driven will always remain the same; what WILL change is the direction of drive.
e.g. with no idlers, the driver turns clockwise (CW), the driven turns counter-clockwise (CCW)
With one idler, the driver turns CW, the idler turns CCW, so the driven turns CW.
2 idlers it goes CW, CCW, CW, CCW
3 idilers you get CW, CCW, CW, CCW, CW
and so on.
ed in cny:
Well with replies like these it is clear to me. I had envisioned it be be reducing the speed, which it will around it's own shaft, but outside speed will travel as fast as it originally did. :doh: Thanks guys for the corrections. I'll look into this idea and see if I have clearance.
I am also still looking for gearing as well but seem to find them hard to get in what I need. Maybe I would be able to make the. However they would need to be made of something I can work like wood or plastic as I haven't the capabilities to machine yet.
Rob.Wilson:
Hi Ed
You could make wooden gears http://woodgears.ca/gear/howto.html
http://woodgears.ca/gear_cutting/template.html :thumbup: interesting site :dremel:
Rob
ed in cny:
Yes that is the site that I got my idea from. I have a number of CNC's and a waterjet for cutting stone and solid surface countertops where I work. The waterjet could cut the aluminum but it's a gamble as it's geared to cut stone and the tolerances are may to big to be of any use to me. The CNC's are geared for the product being cut and to do anything for most of them would be not work the time. I may be able to use one that cuts wood but will have to work up a program. I also may find that the gears will be to noisy for the small organ and opt for something else. Working with this site how does one make the the size gear that you want? I can find where you state diameter?
I didn't think this was so hard. I though just a quick fix with a couple gears and done. I didn't figure I'd be trying to reinvent the wheel. I'm getting ready to set this thing aside as it's is getting me fed up.
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