Looking for help choosing/designing gear set(s) to prototype product

[SHartman]

Hi Gearheads,

I'm looking for someone with lots of gear knowledge, especially with bevel gears, to advise/consult on a project I have. Would like guidance on what type of gears will be best for my application, and then possibly to design or select those gears from existing products.

I'm building a simple consumer product which will be hand operated. A wheel rolling on the ground will rotate the primary gear at about 120 rpm. I believe there may be 2 good options to achieve my goal:
Primary gear 1 would spin a smaller pinion on a shaft to a second gear, which would spin a second pinion. Desired output speed is between 4,000-9,000 rpm.
Primary gear 1 could be a hub (with internal planetary gears if useful/needed), driving a belt to a second gear, which would spin a second pinion. Same goal of 4,000-9,000 rpm.
Plane from gear 1 to pinion 2 will be a 90 degree shift (vertical to horizontal) with about a 12" span. Max diameter of gear 1 & 2 will be around 8".

One of these options, or a combination of may work, or an entirely different arrangement may be needed/best. That's where I'm looking for expertise. What type of arrangement, and what type of gears. It could be a transmission of some type to get the speeds I'm looking for in the easiest most efficient way possible.

My goal for the gears is to be efficient as possible with reasonable cost. Low energy loss, low noise, low wear, low maintenance. Minimal force will be used, and I believe composite materials should be fine, but I'm not opposed to metal gears if easier/better. Initially I believed Hypoid would be needed and would be the best fit, but I now believe more simple bevel or spiral bevel may be better.

Hopefully this describes the goal I'm trying to achieve well enough. I'm limiting full disclosure of the project without an NDA, but can easily provide if you would want/need more detail. Please let me know additional questions and I'll answer if I can.

I'm bootstrapping this project, but willing to pay fair market for consulting and/or design work. I'm also able to offer an internship if a student had the correct skillset & goals and was looking for an internship opportunity.

Thank you,
Scott

[ArtF]

Hi Scott:

  I dont think Im qualified to design such a thing, a 75:1 transmission would
have properties available that make it really tied to the project as to which way to go.
Theres just too many ways to do that, but in the end the rule is always the fewer
moving parts the better. More so when you need 75:1 step up in speed.
Hopefully, someone round here has some experience in such a device...

Art